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  • 1.
    Andersson, Matilda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Urbonaite, Sigita
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Magnetron sputtering of Zr-Si-C thin films2012In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, no 20, p. 6375-6381Article in journal (Refereed)
    Abstract [en]

    The phase composition and chemical bonding of Zr-C and Zr-Si-C films deposited by magnetron sputtering has been studied. The results show that the binary Zr-C films at higher carbon contents form nanocrystallites of ZrC in an amorphous carbon matrix. The addition of Si induces a complete amorphization of the films above a critical concentration of about 15 at.%. X-ray diffraction and transmission electron microscopy confirm that the amorphous films contain no nanocrystallites and therefore can be described as truly amorphous carbides. The amorphous films are thermally stable but start to crystallize above 500 degrees C. Analysis of the chemical bonding with X-ray photoelectron spectroscopy suggests that the amorphous films exhibit a mixture of different chemical bonds such as Zr-C, Zr-Si and Si-C and that the electrical and mechanical properties are dependent on the distribution of these bonds. For higher carbon contents, strong Si-C bonds are formed in the amorphous Zr-Si-C films making them harder than the corresponding binary Zr-C films.

  • 2.
    André, Benny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Friction and contact resistance of nanocomposite Ti-Ni-C coatings2011In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 270, no 9-10, p. 555-566Article in journal (Refereed)
    Abstract [en]

    Ceramic nanocomposite coatings in the Ti-Ni-C were deposited using PVD and studied with respect to tribological properties and contact resistance. It was shown that coatings could be deposited combining of a low contact resistance and a low friction coefficient against silver, making them suitable for use in high performance electrical contacts.Nine coatings with different amounts of C and Ni were deposited. Coatings on flat Ni plated copper substrates were tested in a tribological ball-on-disc setup against ball bearing steel balls. Depending on primarily the amount of carbon the coatings showed very different friction coefficient and wear rate. The coatings were also deposited on cylindrical Ni plated copper substrates. Using geometrically identical silver plated cylinders as counter surface these were evaluated in a test setup better resembling a real life electrical contact. For most coatings a low electrical contact resistance was measured. The evolution of friction coefficient and contact resistance was correlated to wear marks and contact tracks, with their generated tribofilms, as examined after testing using electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy.

  • 3.
    André, Benny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Lindquist, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Tribological testing of ceramic coatings boosted for low friction and for use in electrical contacts2008Conference paper (Refereed)
  • 4.
    Barker, Paul Michael
    et al.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Konstantinidis, Stephanos
    Chimie des Interactions Plasma-Surface (ChIPS), Université de Mons, Belgium.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Britun, Nikolay
    Chimie des Interactions Plasma-Surface (ChIPS), Université de Mons, Belgium.
    Patscheider, Jörg
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    An investigation of c-HiPIMS discharges during titanium deposition2014In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 258, p. 631-638Article in journal (Refereed)
    Abstract [en]

    Abstract A modified version of high power impulse magnetron sputtering (HiPIMS) has been used to deposit titanium films at higher deposition rates than for conventional HiPIMS whilst maintaining similar pulse voltages and peak currents. This process, named chopped-HiPIMS (c-HiPIMS) utilises pulses decomposed into several short single pulses instead of single HiPIMS pulses. Experiments show that manipulating the pulse sequence during c-HiPIMS, i.e. the tÎŒon and tÎŒoff times (explained in the glossary) allows for an increase of the deposition rate; increases of up to 150% are reported here for selected conditions. Further, deposition rates higher than those measured using direct current magnetron sputtering are also shown. Investigations by optical emission and optical absorption spectroscopy at the substrate show that the increase of deposition rate is not a consequence of different ion concentrations arriving at the substrate when changing the micro-pulse-off times of c-HiPIMS. Thus alternative reasons for the enhanced deposition rate during c-HiPIMS deposition of metal films are discussed. It is demonstrated that film micro-structure maintains the void free, dense nature typically demonstrated by HiPIMS deposited coatings whilst at enhanced deposition rates. Thus c-HiPIMS allows for the preparation of dense films with the benefit of faster growth rates.

  • 5. Barker, Paul Michael
    et al.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Patscheider, Jorg
    Modified high power impulse magnetron sputtering process for increased deposition rate of titanium2013In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 31, no 6, p. 060604-Article in journal (Refereed)
    Abstract [en]

    A modified version of high power impulse magnetron sputtering (HiPIMS) has been used to deposit titanium films at higher deposition rates than for conventional HiPIMS while maintaining similar pulse voltages and peak currents. In the present study, additional control parameters are explored through the chopping of the HiPIMS pulse into a pulse sequence. Experiments show that the use of sequences allows for an increase of the deposition rate of more than 45% compared to conventional HiPIMS. The increase in deposition rate is ascribed to a combination of reduced gas rarefaction effects, prevention of sustained self-sputtering, and a relaxation of ion trapping.

  • 6.
    Bijelovic, Stojanka
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Råsander, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Wilhelmsson, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wear-resistant magnetic thin film material based on a Ti1−xFexC1−y nanocomposite alloy2010In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 81, no 1, p. 014405-Article in journal (Refereed)
    Abstract [en]

    In this study we report on the film growth and characterization of thin films deposited on amorphous quartz. The experimental studies have been complemented by first-principles density-functional theory metastable Ti-Fe-C film changes. With increasing annealing time, there is a depletion of iron close to the surface of the film, while regions enriched in iron are simultaneously formed deeper into the film. Both the magnetic ordering temperature and the saturation magnetization changes significantly upon annealing. The DFT calculations show that the critical temperature and the magnetic moment both increase with increasing Fe and C-vacancy concentration. The formation of the metastable iron-rich Ti-Fe-C compound is reflected in the strong increase in the magnetic ordering temperature. Eventually, after enough annealing time nanocrystalline -Fe starts to precipitate, the amount and size of which can be controlled by the annealing procedure; after 20 min of annealing, the experimental results indicate a nanocrystalline iron-film embedded in a wear-resistant TiC compound. This conclusion is further supported by transmission electron microscopy studies on epitaxial Ti-Fe-C films deposited on single-crystalline MgO substrates where, upon annealing, an iron film embedded in TiC is formed. Our results suggest that annealing of metastable Ti-Fe-C films can be used as an efficient way of creating a wear-resistant magnetic thin film material. approximately 50-nm-thick Ti-Fe-CDFT calculations. Upon annealing of as-prepared films, the composition of the10 min, nanocrystalline -Fe starts to precipitate, the amount and size of which can be controlled by the annealing procedure; after 20 min of annealing, the experimental results indicate a nanocrystalline iron-film embedded in a wear-resistant TiC compound. This conclusion is further supported by transmission electron microscopy studies on epitaxial Ti-Fe-C films deposited on single-crystalline MgO substrates where, upon annealing, an iron film embedded in TiC is formed. Our results suggest that annealing of metastable Ti-Fe-C films can be used as an efficient way of creating a wear-resistant magnetic thin film material.

  • 7.
    Boettger, P. H. M.
    et al.
    Laboratory of Crystallography, Department of Materials, ETH Zürich, Zürich, Switzerland.
    Lewin, Erik
    Laboratory of Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Patscheider, J.
    Laboratory of Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Shklover, V.
    Laboratory of Crystallography, Department of Materials, ETH Zürich, Zürich, Switzerland.
    Cahill, D. G.
    Department of Materials Science and Engineering, University of Illinois, Urbana, USA.
    Ghisleni, R.
    Laboratory for Mechanics of Materials and Nanostructures, Empa, Thun, Switzerland.
    Sobiech, M.
    Oerlikon Balzers Coating AG, Balzers, Liechtenstein.
    Thermal conductivity of hard oxynitride coatings2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 549, p. 232-238Article in journal (Refereed)
  • 8.
    Bottger, P. H. M.
    et al.
    Laboratory of Nanoscale Materials Science, EMPA, Dübendorf, Switzerland .
    Braginsky, L.
    Laboratory of Crystallography, ETH Zürich, Zürich, Switzerland.
    Shklover, V.
    Laboratory of Crystallography, ETH Zürich, Zürich, Switzerland.
    Lewin, Erik
    Laboratory of Nanoscale Materials Science, EMPA, Dübendorf, Switzerland .
    Patscheider, J.
    Laboratory of Nanoscale Materials Science, EMPA, Dübendorf, Switzerland .
    Cahill, D. G.
    Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois, USA .
    Sobiech, M.
    Oerlikon Balzers Coating AG, Balzers, Principality of Liechtenstein .
    Hard wear-resistant coatings with anisotropic thermal conductivity for high thermal load applications2014In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, no 1, p. 013507-Article in journal (Refereed)
    Abstract [en]

    High thermal load applications such as high speed dry cutting lead to high temperatures in the coated tool substrate that can soften the tool and high temperature gradients that can put stress on the coating/tool interface. In this work, theoretical considerations are presented for multilayer and graded protective coatings that can induce a significant anisotropy in their thermal conductivity. Solution of the heat equation shows that anisotropy of thermal conductivity has the potential to reduce temperatures and temperature gradients arising due to brief, localized heat at the coating surface ("hot-spots"). Experimental realization of high anisotropy is demonstrated in TiN/AlCrN multilayer coatings with variable layer thickness. In the coating with 50 nm bilayer periodicity, the highest anisotropy was obtained with a value of kappa(parallel to)/kappa(perpendicular to) = 3.0 +/- 0.9. Time-domain thermoreflectance is used to measure in-plane and cross-plane thermal conductivity of fabricated coatings. The observed high values of anisotropy of thermal conductivity are compared with theoretical predictions and its realisation is discussed with regard to the coating microstructure.

  • 9.
    Cedervall, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Ivanov, Sergey A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Karpov Inst Phys Chem, Ctr Mat Sci, Vorontsovo Pole 10, Moscow 105064, Russia;Uppsala Univ, Dept Engn Sci, Box 534, S-75121 Uppsala, Sweden.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, S-75121 Uppsala, Sweden.
    Beran, Premysl
    ESS, Tunavagen 24, S-22363 Lund, Sweden;Acad Sci Czech Republ, Nucl Phys Inst, Rez 25068, Czech Republic.
    Andersson, Mikael S.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Faske, Tom
    Tech Univ Darmstadt, Inst Mat & Geowissensch, Alarich Weiss Str 2, D-64287 Darmstadt, Germany.
    Bazuev, Gennadii V.
    Russian Acad Sci, Inst Solid State Chem, Ural Branch, Ekaterinburg 620990, Russia.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    On the structural and magnetic properties of the double perovskite Nd2NiMnO62019In: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 30, no 17, p. 16571-16578Article in journal (Refereed)
    Abstract [en]

    The structural, electronic and magnetic properties of phase pure and stoichiometric samples of the double perovskite Nd2NiMnO6. Photoectron spectroscopy revels a mixed valence of the transition metal sites where Ni has 3+/2+ oxidation states and Mn has 3+/4+. The compound orders ferromagnetically at 195 K. The magnetic structure was determined from the refinement of the neutron diffraction data. The results suggests that the B-site magnetic moments align along the crystallographic a-direction.

  • 10.
    Folkenant, Matilda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nygren, Kristian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Malinovskis, Paulius
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Palisaitis, Justinas
    Persson, Per
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Structure and properties of Cr-C/Ag films deposited by magnetron sputtering2015In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 281, p. 184-192Article in journal (Refereed)
    Abstract [en]

    Cr-C/Ag thin films with 0-14 at% Ag have been deposited by magnetron sputtering from elemental targets. The samples were analyzed by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) to study their structure and chemical bonding. A complex nanocomposite structure consisting of three phases; nanocrystalline Ag, amorphous CrCx and amorphous carbon is reported. The carbon content in the amorphous carbide phase was determined to be 32-33 at% C, independent of Ag content Furthermore, SEM and XPS results showed higher amounts of Ag on the surface compared to the bulk. The hardness and Young's modulus were reduced from 12 to 8 GPa and from 270 to 170 GPa, respectively, with increasing Ag content. The contact resistance was found to decrease with Ag addition, with the most Ag rich sample approaching the values of an Ag reference sample. Initial tribological tests gave friction coefficients in the range of 0.3 to 0.5, with no clear trends. Annealing tests show that the material is stable after annealing at 500 degrees C for 1 h, but not after annealing at 800 degrees C for 1 h. In combination, these results suggest that sputtered Cr-C/Ag films could be potentially applicable for electric contact applications.

  • 11.
    Fritze, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Koller, Christian M.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    von Fieandt, Linus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Malinovskis, Paulius
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Johansson, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mayrhofer, Paul H.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Influence of Deposition Temperature on the Phase Evolution of HfNbTiVZr High-Entropy Thin Films2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 4, article id 587Article in journal (Refereed)
    Abstract [en]

    In this study, we show that the phase formation of HfNbTiVZr high-entropy thin films is strongly influenced by the substrate temperature. Films deposited at room temperature exhibit an amorphous microstructure and are 6.5 GPa hard. With increasing substrate temperature (room temperature to 275 degrees C), a transition from an amorphous to a single-phased body-centred cubic (bcc) solid solution occurs, resulting in a hardness increase to 7.9 GPa. A higher deposition temperature (450 degrees C) leads to the formation of C14 or C15 Laves phase precipitates in the bcc matrix and a further enhancement of mechanical properties with a peak hardness value of 9.2 GPa. These results also show that thin films follow different phase formation pathways compared to HfNbTiVZr bulk alloys.

  • 12.
    Fritze, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Malinovskis, Paulius
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Riekehr, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    von Fieandt, Linus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Hard and crack resistant carbon supersaturated refractory nanostructured multicomponent coatings2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 14508Article in journal (Refereed)
    Abstract [en]

    The combination of ceramic hardness with high crack resistance is a major challenge in the design of protective thin films. High entropy alloys have shown in earlier studies promising mechanical properties with a potential use as thin film materials. In this study, we show that small amounts of carbon in magnetron-sputtered multicomponent CrNbTaTiW films can lead to a significant increase in hardness. The film properties were strongly dependent on the metal composition and the most promising results were observed for TaW-rich films. They crystallised in a bcc structure with a strong (110) texture and coherent grain boundaries. It was possible to deposit films with 8 at.% C in a supersaturated solid-solution into the bcc structure without carbide formation. A major effect of carbon was a significant grain refinement, reducing the column diameter from approximately 35 to 10 nm. This resulted in an increase in hardness from 14.7 to 19.1 GPa while the reduced E-modulus stayed constant at 322 GPa. The carbon-containing films exhibited extremely little plastic deformation around the indent and no cracks were observed. These results show that supersaturation of carbon into high entropy films can be a promising concept to combine superior hardness with high crack resistance.

  • 13.
    Garlisi, Corrado
    et al.
    Khalifa Univ Sci & Technol, Dept Chem Engn, Masdar Inst, POB 54224, Abu Dhabi, U Arab Emirates..
    Szlachetko, Jakub
    Jan Kochanowski Univ Humanities & Sci, Inst Phys, Kielce, Poland.;Polish Acad Sci, Inst Phys Chem, Warsaw, Poland..
    Aubry, Cyril
    Khalifa Univ Sci & Technol, Dept Mech Engn, Masdar Inst, POB 54224, Abu Dhabi, U Arab Emirates..
    Fernandes, Daniel L. A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hattori, Yocefu
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Paun, Cristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Pavliuk, Mariia V.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Rajput, Nitul S.
    Khalifa Univ Sci & Technol, Dept Mech Engn, Masdar Inst, POB 54224, Abu Dhabi, U Arab Emirates..
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Sá, Jacinto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Polish Acad Sci, Inst Phys Chem, Warsaw, Poland.
    Palmisano, Giovanni
    Khalifa Univ Sci & Technol, Dept Chem Engn, Masdar Inst, POB 54224, Abu Dhabi, U Arab Emirates..
    N-TiO2/Cu-TiO2 double-layer films: Impact of stacking order on photocatalytic properties2017In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 353, p. 116-122Article in journal (Refereed)
    Abstract [en]

    In this work, we report for the first time a unique configuration of N-doped and Cu-doped TiO2 bilayer. The activity of TiO2 was improved by combining Cu- and N-doping in a layered thin-film structure. The impact of the stacking order was studied, pointing out how the best arrangement is by far the one with Cu-TiO2 as the top layer. The results reveal a unique and simple way to enhance the photocatalytic response of TiO2 in the visible domain.

  • 14.
    Glechner, T.
    et al.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    Mayrhofer, P. H.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    Holec, D.
    Univ Leoben, Dept Mat Sci, A-8700 Leoben, Austria.
    Fritze, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Paneta, Valentina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kolozsvari, S.
    Plansee Composite Mat GmbH, D-86983 Lechbruck, Germany.
    Riedl, H.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    Tuning structure and mechanical properties of Ta-C coatings by N-alloying and vacancy population2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 17669Article in journal (Refereed)
    Abstract [en]

    Tailoring mechanical properties of transition metal carbides by substituting carbon with nitrogen atoms is a highly interesting approach, as thereby the bonding state changes towards a more metallic like character and thus ductility can be increased. Based on ab initio calculations we could prove experimentally, that up to a nitrogen content of about 68% on the non-metallic sublattice, Ta-C-N crystals prevail a face centered cubic structure for sputter deposited thin films. The cubic structure is partly stabilized by non-metallic as well as Ta vacancies-the latter are decisive for nitrogen rich compositions. With increasing nitrogen content, the originally super-hard fcc-TaC0.71 thin films soften from 40 GPa to 26 GPa for TaC0.33N0.67, accompanied by a decrease of the indentation modulus. With increasing nitrogen on the non-metallic sublattice (hence, decreasing C) the damage tolerance of Ta-C based coatings increases, when characterized after the Pugh and Pettifor criteria. Consequently, varying the non-metallic sublattice population allows for an effective tuning and designing of intrinsic coating properties.

  • 15. Ingason, A. S.
    et al.
    Eriksson, A. K.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jensen, J.
    Olafsson, S.
    Growth and structural properties of Mg:C thin films prepared by magnetron sputtering2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 15, p. 4225-4230Article in journal (Refereed)
    Abstract [en]

    We investigate the growth and structure properties of Mg:C thin films. The films are prepared using a dc magnetron sputtering discharge where the electrical resistance over the films is monitored during growth in-situ with a four point probe setup. The structural properties of the films are investigated using X-ray diffraction measurements and the elemental composition and binding in the films is determined using elastic recoil detection analysis and X-ray photoelectron spectroscopy. The results show that during co-sputtering the carbon flux influences the initial stages of the film growth. The films are made of polycrystalline magnesium grains embedded in a carbon network, the size of which depends on the carbon content, but amorphous phases cannot be excluded. The XPS measurements show the presence of carbidic carbon whereas X-ray measurements find no Mg:C phases. The overall stability of the films is found to depend on the carbon content, where stable films capped with a 14 nm Pd layer cannot be obtained with carbon content above 18%.

  • 16.
    Ivanov, Sergey
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Karpov Inst Phys Chem, Ctr Mat Sci, Vorontsovo Pole 10, Moscow Russia.
    Andersson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Cedervall, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Bazuev, G. V.
    Russian Acad Sci, Inst Solid State Chem, Ural Branch, Ekaterinburg 620990, Russia.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Temperature-dependent structural and magnetic properties of R2MMnO6 double perovskites (R=Dy, Gd; M=Ni, Co)2018In: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 29, no 21, p. 18581-18592Article in journal (Refereed)
    Abstract [en]

    The structural and magnetic properties of the Dy2CoMnO6, Dy2NiMnO6 and Gd2CoMnO6 double perovskites are investigated using X-ray powder diffraction and squid magnetometry. The materials adopt an orthorhombic structure (space ground Pnma) with disordered Co(Ni)/Mn cations, and exhibit ferrimagnetic transitions near T(C)85, 95, and 115K respectively. T-C was found to monotonously depend on the orthorhombic distortion (a-c)/(a+c) of the compounds. The crystal structure of the compounds was investigated as a function of temperature (16-1100K range), evidencing changes in the BO6 octahedron near T-C. The magnetic entropy changes are estimated for comparison of the magnetocaloric properties to those from literature.

  • 17.
    Jansson, Ulf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Carbon-containing multi-component thin films2019In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 688, article id 137411Article, review/survey (Refereed)
    Abstract [en]

    High entropy alloys (HEAs) have been a hot research area for many years. They are solid solutions of at least five elements in approximately equimolar compositions. The HEAs are assumed to be stabilized by a high entropy of mixing favouring a solid solution phase instead of a mixture of intermetallic phases. The importance of entropy of mixing and the true nature of HEAs are debated but the concept has contributed to an interesting development of new alloys. They idea of stabilizing solid solutions with many elements have recently been expanded to nitrides, borides, oxides and carbides. Furthermore, a growing number of thin film studies of these compounds are now published. In this paper we summarise recent results from studies of carbon-containing multi-component thin films based on the HEA concept. We will summarise some general observations connected to "high-entropy" materials. We also describe some general trends in metal-carbon interactions for transition metals and discuss how they should influence the formation of multi-component carbides. A summary of results on bulk multi-component carbide materials is also presented. We review published studies of carbon-containing multi-component thin films mainly deposited with magnetron-sputtering. The crystal structure, microstructure and properties of these films are described. Finally, we highlight some interesting topics for future research.

  • 18.
    Jansson, Ulf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Sputter deposition of transition-metal carbide films - A critical review from a chemical perspective2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 536, p. 1-24Article, review/survey (Refereed)
    Abstract [en]

    Thin films based on transition-metal carbides exhibitmany interesting physical and chemical properties making them attractive for a variety of applications. The most widely used method to produce metal carbide films with specific properties at reduced deposition temperatures is sputter deposition. A large number of papers in this field have been published during the last decades, showing that large variations in structure and properties can be obtained. This review will summarise the literature on sputter-deposited carbide films based on chemical aspects of the various elements in the films. By considering the chemical affinities (primarily towards carbon) and structural preferences of different elements, it is possible to understand trends in structure of binary transition-metal carbides and the ternary materials based on these carbides. These trends in chemical affinity and structure will also directly affect the growth process during sputter deposition. A fundamental chemical perspective of the transition-metal carbides and their alloying elements is essential to obtain control of the material structure (from the atomic level), and thereby its properties and performance. This review covers a wide range of materials: binary transition-metal carbides and their nanocomposites with amorphous carbon; the effect of alloying carbide-based materials with a third element (mainly elements from groups 3 through 14); as well as the amorphous binary and ternary materials from these elements deposited under specific conditions or at certain compositional ranges. Furthermore, the review will also emphasise important aspects regarding materials characterisation which may affect the interpretation of data such as beam-induced crystallisation and sputter-damage during surface analysis. 

  • 19.
    Jansson, Ulf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Råsander, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    André, Benny
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Design of carbide-based nanocomposite thin films by selective alloying2011In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 206, no 4, p. 583-590Article in journal (Refereed)
    Abstract [en]

    This paper reviews a series of studies on alloying of sputtered TiC coatings with weak carbide-forming metals, Me, such as Al, Fe, Ni, Pt and Cu. Metastable solid solutions with Me on the Ti sites are easily obtained by magnetron sputtering at low temperatures (< 300 °C). First principles density functional theory (DFT) calculations of such carbides show that a driving force exists to remove carbon from the structure as an alternative and kinetically more favourable route compared to Me precipitation. This leads to a situation where additional control of the phase composition is given by annealing: both direct influence during film growth, as well as through subsequent annealing. Thus, alloying of the nanocomposite with weak carbide-forming metals can be used to tune many mechanical, electric and magnetic properties of a carbide-based nanocomposite film.

  • 20.
    Johansson, E
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Platzer-Björkman, C
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Rensmo, H
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Sandell, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Stolt, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Gorgoi, M
    Svensson, S
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Schäfers, F
    Braun, W
    Eberhardt, W
    HIKE experiments at KMC-1: Studies of Solar Cell Materials2007In: Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung m.b.H. (BESSY) Annual Report (2006), no 508-509Article in journal (Refereed)
  • 21.
    Johansson, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Influence of oxygen content on structure and material properties of reactively sputtered Al-Ge-O-N thin films2018In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 738, p. 515-527Article in journal (Refereed)
    Abstract [en]

    Ternary Al-Ge-N and quaternary Al-Ge-O-N coatings were deposited by reactive dc magnetron cosputtering of Al and Ge targets in an Ar/N-2 or Ar/N-2/O-2 atmosphere at a substrate temperature of 250 degrees C. The structure and material properties of the coatings were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nanoindentation, UV-vis spectroscopy and optical profilometry. In agreement with literature, the ternary Al-Ge-N coatings were found to be nanocomposite materials with nanocrystalline (Al1-xGex) N-y solid solution phase in a Ge3N4-z amorphous matrix. The Al-Ge-O-N coatings consisted of a nanocrystalline wurzite-type (Al1-xGex)( N1-yOy) solid solution phase for low oxygen concentrations with a possible co-existence of an amorphous Ge-N matrix phase. For higher O contents, the coatings became X-ray amorphous. The mechanical properties of the Al-Ge-O-N films were improved for low oxygen content, as compared to the ternary Al-Ge-N samples, showing an increase in hardness up to 29 GPa and Young's modulus to 320 GPa. The oxygen addition also resulted in an additional design parameter of the optical properties compared to the ternary Al-Ge-N films. The optical absorption edge was thus tuneable towards both shorter and longer wavelength by changing the O and Ge content respectively, and ranged from 302 to 373 nm, corresponding to an optical bandgap (E-04) between 4.1 and 3.3 eV. After annealing of the Al-Ge-O-N coatings in ultra-high vacuum at 500 degrees C, indications of increased thermal stability for the coating with high oxygen content were observed. For the annealed Al-Ge-O-N films the mechanical properties were improved upon heat treatment, while the optical properties were only slightly changed. These results suggests that coatings of the Al-Ge-O-N system could be suitable as protective optical coatings at elevated temperatures.

  • 22.
    Johansson, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Structure-property correlations in reactively sputtered Al-Ge-O-N thin films2016Conference paper (Other academic)
  • 23.
    Johansson, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Riekehr, Lars
    Fritze, Stefan
    Multicomponent Hf-Nb-Ti-V-Zr nitride coatings by reactive magnetronsputter deposition2018In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 49, no 15 sept, p. 529-539Article in journal (Refereed)
    Abstract [en]

    Multicomponent nitride coatings of the Hf-Nb-Ti-V-Zr system with different Hf content (0–18 at.%) were deposited using reactive dc magnetron sputtering. Coatings with lower Hf content (0–7 at.%) were found to consist of a single solid solution phase with NaCl-type structure (space group Fm-3" role="presentation">m). Coatings with higher Hf content (10–18 at.%) showed a two-phase material consisting of cubic Fm-3" role="presentation">m and tetragonal I4/mmm solid solution phase. The lattice distortion, estimated by calculating the δ-parameter under the assumption of a single solid solution phase, varied between 3.8 and 4.0% and slightly decreased with increasing Hf content. SEM and TEM cross section images showed a columnar microstructure with columns that were frayed on the surface or throughout the whole column. The column size decreased as Hf content increased. The hardness increased from 8 to 19 GPa with increased Hf content, which most probably is related to the change in microstructure rather than change in lattice distortion. The electrical resistivity for all samples ranged between 231 and 286 μΩcm.

  • 24.
    Johansson, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Uppsala Univ, Angstrom Lab, Dept Chem, Inorgan Res Programme, Box 538, SE-75121 Uppsala, Sweden.
    Riekehr, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Fritze, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Multicomponent Hf-Nb-Ti-V-Zr nitride coatings by reactive magnetron sputter deposition2018In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 349, p. 529-539Article in journal (Refereed)
    Abstract [en]

    Multicomponent nitride coatings of the Hf-Nb-Ti-V-Zr system with different Hf content (0-18 at.%) were deposited using reactive dc magnetron sputtering. Coatings with lower Hf content (0-7 at.%) were found to consist of a single solid solution phase with NaCl-type structure (space group Fm-3m). Coatings with higher Hf content (10-18 at.%) showed a two-phase material consisting of cubic Fm-3m and tetragonal I4/m:run solid solution phase. The lattice distortion, estimated by calculating the delta-parameter under the assumption of a single solid solution phase, varied between 3.8 and 4.0% and slightly decreased with increasing Hf content. SEM and TEM cross section images showed a columnar microstructure with columns that were frayed on the surface or throughout the whole column. The column size decreased as Hf content increased. The hardness increased from 8 to 19 GPa with increased Hf content, which most probably is related to the change in microstructure rather than change in lattice distortion. The electrical resistivity for all samples ranged between 231 and 286 mu Omega cm.

  • 25.
    Kumar, Ankit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wetterskog, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Tai, Cheuk-Wai
    Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden.
    Akansel, Serkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Husain, Sajid
    Department of Physics, Indian Institute of Technology Delhi, New Delhi, India.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Brucas, Rimantas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Chaudhary, Sujeet
    Department of Physics, Indian Institute of Technology Delhi, New Delhi, India.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Effect of in situ electric-field-assisted growth on antiphase boundaries in epitaxial Fe3O4 thin films on MgO2018In: Physical Review Materials, ISSN 2475-9953, Vol. 2, no 5, article id 054407Article in journal (Refereed)
    Abstract [en]

    Antiphase boundaries (APBs) normally form as a consequence of the initial growth conditions in all spinel ferrite thin films. These boundaries result from the intrinsic nucleation and growth mechanism, and are observed as regions where the periodicity of the crystalline lattice is disrupted. The presence of APBs in epitaxial films of the inverse spinel Fe3O4 alters their electronic and magnetic properties due to strong antiferromagnetic (AF) interactions across these boundaries. We explore the effect of using in-plane in situ electric-field-assisted growth on the formation of APBs in heteroepitaxial Fe3O4(100)/MgO(100) thin films. The electric-field-assisted growth is found to reduce the AF interactions across APBs and, as a consequence, APB-free thin-film-like properties are obtained, which have been probed by electronic, magnetic, and structural characterization. The electric field plays a critical role in controlling the density of APBs during the nucleation process by providing an electrostatic force acting on adatoms and therefore changing their kinetics. This innovative technique can be employed to grow epitaxial spinel thin films with controlled AF interactions across APBs.

  • 26. Lauridsen, J.
    et al.
    Eklund, P.
    Jensen, J.
    Ljungcrantz, H.
    Öberg, A.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Flink, A.
    Högberg, H.
    Hultman, L.
    Microstructure evolution of Ti-Si-C-Ag nanocomposite coatings deposited by DC magnetron sputtering2010In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 58, no 20, p. 6592-6599Article in journal (Refereed)
    Abstract [en]

    Nanocomposite coatings consisting of Ag and TiCx (x < 1) crystallites in a matrix of amorphous SiC were deposited by high-rate magnetron sputtering from Ti-Si-C-Ag compound targets. Different target compositions were used to achieve coatings with a Si content of similar to 13 at.%, while varying the C/Ti ratio and Ag content. Electron microscopy, helium ion microscopy, X-ray photoelectron spectroscopy and X-ray diffraction were employed to trace Ag segregation during deposition and possible decomposition of amorphous SiC. Eutectic interaction between Ag and Si is observed, and the Ag forms threading grains which coarsen with increased coating thickness. The coatings can be tailored for conductivity horizontally or vertically by controlling the shape and distribution of the Ag precipitates. Coatings were fabricated with hardness in the range 10-18 GPa and resistivity in the range 77-142 mu Omega cm.

  • 27. Lauridsen, J.
    et al.
    Eklund, P.
    Joelsson, T.
    Ljungcrantz, H.
    Öberg, Å.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Beckers, M.
    Högberg, H.
    Hultman, L.
    High-rate deposition of amorphous and nanocomposite Ti-Si-C multifunctional coatings2010In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, no 2, p. 299-305Article in journal (Refereed)
    Abstract [en]

    Amorphous (a) and nanocomposite Ti-Si-C coatings were deposited at rates up to 16 mu m/h by direct current magnetron sputtering from a Ti3SiC2 compound target, using an industrial pilot-plant system, onto high-speed steel. Si, and SiO2 substrates as well as NI-plated Cu cylinders, kept at a temperature of 200 or 270 degrees C. Electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analyses showed that TiC/a-C/a-SiC nanocomposites were formed consisting of textured TIC nanocrystallites (nc) embedded in a matrix of a-C and a-SiC. Elastic recoil detection analysis showed that coatings deposited at a target-to-substrate distance of 2 cm and an Ar pressure of 10 mTorr have a composition close to that of the Ti3SiC2 compound target, as explained by ballistic transport of the species Increased target-to-substrate distance from 2 cm to 8 cm resulted in a higher carbon-to-titanium ratio in the coatings than for the Ti3SiC2 compound target, due to different gas-phase scattering properties between the sputtered species The coating microstructure could be modified from nanocrystalline to predominantly amorphous by changing the pressure and target-to-substrate conditions to 4 mTorr and 2 cm, respectively. A decreased pressure from 10 mTorr to 4 or 2 mTorr at a target-to-substrate distance of 2 cm decreased the deposition rate up to a factor of similar to 7 as explained by resputtering and an increase in the plasma sheath thickness. The coatings exhibited electrical resistivity in the range 160-800 mu Omega cm, contact resistance down to 08 m Omega at a contact force of 40 N, and nanoindentation hardness in the range of 6-38 GPa.

  • 28.
    Lauridsen, J.
    et al.
    Dept. of Phys., Linkoping Univ., Linköping, Sweden.
    Jun, Lu
    Dept. of Phys., Linkoping Univ., Linköping, Sweden.
    Eklund, P.
    Dept. of Phys., Linkoping Univ., Linköping, Sweden.
    Hultman, L.
    Dept. of Phys., Linkoping Univ., Linköping, Sweden.
    Oberg, A.
    ABB Corporate Research, Västerås, Sweden.
    Lindgren, M.
    SP Technical Research Institute of Sweden.
    Fast, L.
    SP Technical Research Institute of Sweden.
    Lewin, E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Jansson, U.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Deposition of Ti-Si-C-Ag Nanocomposite Coatings as Electrical Contact Material2010In: 2010 Proceedings of the 56th IEEE Holm Conference on Electrical Contacts (Holm 2010), p. 7-7Article in journal (Refereed)
  • 29.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Design of carbide-based nanocomposite coatings2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis research on synthesis, microstructure and properties of carbide-based coatings is reported. These coatings are electrically conducting, and can be tailored for high hardness, low friction and wear, along with load-adaptive behaviour. Tailoring these properties is achieved by controlling the relative phase content of the material. Coatings have been synthesised by dc magnetron sputtering, and their structures have been characterised, mainly by X-ray photoelectron spectroscopy and X-ray diffraction.

    It has been shown that nanocomposites comprising of a nanocrystalline transition metal carbide (nc-MeCx, Me = Ti, Nb or V) and an amorphous carbon (a-C) matrix can result in low contact resistance in electrical contacts. Such materials also exhibit low friction and high resistance to wear, making them especially suitable for application in sliding contacts. The lowest contact resistance is attained for small amounts of the amorphous carbon phase.

    It has been shown that specific bonding structures are present in the interface between nc-TiCx and the a-C phases in the nanocomposite.  It was found in particular that Ti3d and C2p states are involved, and that considerable charge transfer occurs across the interface, thereby influencing the structure of the carbide.

    Further design possibilities were demonstrated for TiCx-based nanocomposites by alloying them with weakly carbide-forming metals, i.e., Me = Ni, Cu or Pt.  Metastable supersaturated solid solution carbides, (T1-xMex)Cy, were identified to result from this alloying process. The destabilisation of the TiCx-phase leads to changes in the phase distribution in the deposited nanocomposites, thus providing further control over the amount of carbon phase formed. Additional design possibilities became available through the decomposition of the metastable (Ti1-xMex)Cy phase through an appropriate choice of annealing conditions, yielding either more carbon phase or a new metallic phase involving Me. This alloying concept was also studied theoretically for all 3d transition metals using DFT techniques.

    It has also been demonstrated that Ar-ion etching (commonly used in the analysis of carbide based nanocomposites) can seriously influence the result of the analysis, especially for materials containing metastable phases. This implies that more sophisticated methods, or considerable care are needed in making these analyses, and that many of the earlier published results could well be in error.

    List of papers
    1. Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings
    Open this publication in new window or tab >>Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings
    Show others...
    2009 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 204, no 4, p. 455-462Article in journal (Refereed) Published
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) is a standard method of determining chemical bonding in e.g. nanocomposites. We demonstrate that sputter-cleaning of the sample prior to analysis can substantially alter the attained information. We present an in-depth analysis of sputter damage on binary and ternary TiC-based coatings in the Ti–Ni–C system. XPS was performed after sputter etching with different ion energies (0.15–4 keV). Results are compared to data from the bulk of undamaged samples attained using high kinetic energy XPS. We observe substantial sputter damage, strongly dependent on sputter energies and coating stability. Metastable samples exhibit severe sputter damage after etching with 4 keV. Additional samples from other Ti–Me–C (Me = Al, Fe, Cu or Pt) systems were also examined, and notable sputter damage was observed. This suggests that accurate analysis of any metastable nanocomposite requires careful consideration of sputter damages.

    Place, publisher, year, edition, pages
    Elsevier B.V., 2009
    Keywords
    Sputtering, X-ray photoelectron spectroscopy (XPS), Nanocomposite, Metastable phases, Sputtering artifacts
    National Category
    Chemical Sciences
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-109019 (URN)10.1016/j.surfcoat.2009.08.006 (DOI)000271337500010 ()
    Note
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala, Sweden Department of Physics, The Ångström Laboratory, Uppsala University, Box 530, SE-751 21 Uppsala, Sweden Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13
    2. On the origin of a third spectral component of C1s XPS-spectra for nc-TiC/a-C nanocomposite thin films
    Open this publication in new window or tab >>On the origin of a third spectral component of C1s XPS-spectra for nc-TiC/a-C nanocomposite thin films
    Show others...
    2008 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 202, no 15, p. 3563-3570Article in journal (Refereed) Published
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) spectra of sputter-etched nc-TiC/a-C nanocomposite thin films published in literature show an extra feature of unknown origin in the C1s region. This feature is situated between the contributions of carbide and the carbon matrix. We have used high kinetic energy XPS (HIKE-XPS) on magnetron-sputtered nc-TiC/a-C thin films to show that this feature represents a third chemical environment in the nanocomposites, besides the carbide and the amorphous carbon. Our results show that component is present in as-deposited samples, and that the intensity is strongly enhanced by Ar+-ion etching. This third chemical environment may be due to interface or disorder effects. The implications of these observations on the XPS analysis of nanocomposites are discussed in the light of overlap problems for ternary carbon based systems.

    Keywords
    X-ray photoelectron spectroscopy (XPS), Nanocomposite coatings, Sputtering, Transmission electron microscopy (TEM)
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-16522 (URN)10.1016/j.surfcoat.2007.12.038 (DOI)000255492700016 ()
    Available from: 2008-05-28 Created: 2008-05-28 Last updated: 2017-12-08
    3. Electronic structure and chemical bonding of nanocrystalline-TiC/amorphous-C nanocomposites
    Open this publication in new window or tab >>Electronic structure and chemical bonding of nanocrystalline-TiC/amorphous-C nanocomposites
    2009 (English)In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 80, no 23, p. 235108-Article in journal (Refereed) Published
    Abstract [en]

    The electronic structure of nanocrystalline (nc-) TiC/amorphous C nanocomposites has been investigated bysoft x-ray absorption and emission spectroscopy. The measured spectra at the Ti 2p and C 1s thresholds of thenanocomposites are compared to those of Ti metal and amorphous C. The corresponding intensities of theelectronic states for the valence and conduction bands in the nanocomposites are shown to strongly depend onthe TiC carbide grain size. An increased charge transfer between the Ti 3d-eg states and the C 2p states hasbeen identified as the grain size decreases, causing an increased ionicity of the TiC nanocrystallites. It issuggested that the charge transfer occurs at the interface between the nanocrystalline-TiC and the amorphous-Cmatrix and represents an interface bonding which may be essential for the understanding of the properties ofnc-TiC/amorphous C and similar nanocomposites.

    Keywords
    Nanokomposit, RIXS, XES, XAS, TEY, TFY, XPS, XRD
    National Category
    Condensed Matter Physics Inorganic Chemistry
    Research subject
    Physics; Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-111387 (URN)10.1103/PhysRevB.80.235108 (DOI)000273228800029 ()
    Available from: 2009-12-14 Created: 2009-12-13 Last updated: 2019-06-19Bibliographically approved
    4. Nanocomposite nc-TiC/a-C thin films for electrical contact applications
    Open this publication in new window or tab >>Nanocomposite nc-TiC/a-C thin films for electrical contact applications
    2006 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, no 5, p. 054303-Article in journal (Refereed) Published
    Abstract [en]

    Thin film nanocomposites of nanocrystalline TiC embedded in a matrix of amorphous carbon have been prepared by nonreactive unbalanced dc-magnetron sputtering. These samples have been tested as coating materials for electrical contacts and show great potential as an alternative to traditional metallic coatings for contacts subjected to wear and friction. Through variation of composition and deposition temperature different microstructures have been attained. The coatings have been characterized using x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy. The performance of the coatings has been coupled to the microstructure whereby tuning and optimization possibilities have been identified.

    Keywords
    nanocomposites, titanium compounds, carbon, thin films, wear, friction, sputter deposition, crystal microstructure, X-ray diffraction, X-ray photoelectron spectra, Raman spectra, electrical contacts, contact resistance
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-82095 (URN)10.1063/1.2336302 (DOI)000240602500096 ()
    Available from: 2006-09-18 Created: 2006-09-18 Last updated: 2017-12-14Bibliographically approved
    5. Industrialisation Study of Nanocomposite nc-TiC/a-C Coatings for Electrical Contact Applications
    Open this publication in new window or tab >>Industrialisation Study of Nanocomposite nc-TiC/a-C Coatings for Electrical Contact Applications
    Show others...
    2009 (English)In: Plasma Processes and Polymers, ISSN 1612-8850, Vol. 6, no S1, p. S928-S934Article in journal (Refereed) Published
    Abstract [en]

    Nanocomposite nc-TiC/a-C coatings were prepared by non-reactive magnetron sputtering in industrial scale equipment, under varying deposition conditions in order to investigate upscaling and possible industrialisation. The coatings were found to have similar microstructure and performance compared to previous laboratory scale experiments. The samples were characterised with XRD, XPS and SEM as well with ball-on-disc, nanoindentation and electrical measurements. Coatings containing a small fraction of a-C matrix phase were found to have promising both electrical properties (rho < 400 mu Omega cm and contact resistances down to 0.34 m Omega at 40 N) and tribological properties (f < 0.3 for 10 000 laps).

    Place, publisher, year, edition, pages
    WILEY-VCH Verlag GmbH & Co, 2009
    Keywords
    conductivity, inorganic materials, nanocomposites, thin films, tribology
    National Category
    Chemical Sciences Inorganic Chemistry Engineering and Technology
    Research subject
    Inorganic Chemistry; Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-109022 (URN)10.1002/ppap.200932303 (DOI)000272302900178 ()
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2016-04-14
    6. Carbon Release by Selective Alloying of Transition Metal Carbides
    Open this publication in new window or tab >>Carbon Release by Selective Alloying of Transition Metal Carbides
    Show others...
    2011 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 23, no 35, p. 355401-+Article in journal (Refereed) Published
    Abstract [en]

    We have performed first principles density functional theory calculations on TiC alloyed on the Ti sublattice with 3d transition metals ranging from Sc to Zn. The theory is accompanied by experimental investigations, both as regards materials synthesis as well as characterization. Our results show that by dissolving a metal with a weak ability to form carbides, the stability of the alloy is lowered and a driving force for the release of carbon from the carbide is created. During thin film growth of a metal carbide this effect will favour the formation of a nanocomposite with carbide grains in a carbon matrix. The choice of alloying element as well as its concentration will affect the relative amount of carbon in the carbide and in the carbon matrix. This can be used to design the structures of nanocomposites and their physical and chemical properties. One example of applications is as low-friction coatings. Of the materials studied, we suggest the late 3d transition metals as the most promising elements for this phenomenon, at least when alloying with TiC.

    National Category
    Inorganic Chemistry
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-123136 (URN)10.1088/0953-8984/23/35/355401 (DOI)
    Available from: 2009-10-12 Created: 2009-10-12 Last updated: 2017-12-12Bibliographically approved
    7. Synthesis, structure and properties of Ni-alloyed TiCx-based thin films
    Open this publication in new window or tab >>Synthesis, structure and properties of Ni-alloyed TiCx-based thin films
    Show others...
    2010 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 20, no 28, p. 5950-5960Article in journal (Refereed) Published
    Abstract [en]

    By using non-reactive sputter deposition at low temperatures metastable solid solution phases in the Ti–Ni–C system were synthesized. Produced thin films were either single phase carbides or nanocomposite of nanocrystalline carbide and amorphous C. In the Ni-containing samples a supersaturated solid solution phase (Ti1−xNix)Cy was identified, and was present either as single phase or in a nanocomposite with amorphous C. By modification of the chemical stability of the carbide phase, the addition of Ni was found to strongly promote the formation of amorphous carbon phase in the coatings. Samples have been microstructurally analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Mechanical properties have been evaluated through nanoindentation and pin-on-disc measurements; electrical properties were determined by measurement of the resistivity and the contact resistance. Alloyed nanocomposite coatings were also found to exhibit enhanced tribological and electrical properties, with a decreased resistivity and friction. This makes these thin films very interesting for application in sliding electrical contacts. The mechanisms responsible for the reductions remain to be determined.

    National Category
    Inorganic Chemistry Engineering and Technology
    Research subject
    Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-109034 (URN)10.1039/c0jm00592d (DOI)000279565900025 ()
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    8. Friction and contact resistance of nanocomposite Ti-Ni-C coatings
    Open this publication in new window or tab >>Friction and contact resistance of nanocomposite Ti-Ni-C coatings
    2011 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 270, no 9-10, p. 555-566Article in journal (Refereed) Published
    Abstract [en]

    Ceramic nanocomposite coatings in the Ti-Ni-C were deposited using PVD and studied with respect to tribological properties and contact resistance. It was shown that coatings could be deposited combining of a low contact resistance and a low friction coefficient against silver, making them suitable for use in high performance electrical contacts.Nine coatings with different amounts of C and Ni were deposited. Coatings on flat Ni plated copper substrates were tested in a tribological ball-on-disc setup against ball bearing steel balls. Depending on primarily the amount of carbon the coatings showed very different friction coefficient and wear rate. The coatings were also deposited on cylindrical Ni plated copper substrates. Using geometrically identical silver plated cylinders as counter surface these were evaluated in a test setup better resembling a real life electrical contact. For most coatings a low electrical contact resistance was measured. The evolution of friction coefficient and contact resistance was correlated to wear marks and contact tracks, with their generated tribofilms, as examined after testing using electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy.

    Keywords
    TiC, TiNiC, Friction, Tribofilm, Electrical contacts, Contact resistance
    National Category
    Inorganic Chemistry Engineering and Technology
    Research subject
    Inorganic Chemistry; Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-109425 (URN)10.1016/j.wear.2010.12.006 (DOI)000290132500001 ()
    Available from: 2009-10-15 Created: 2009-10-15 Last updated: 2017-12-12
    9. Carbide and nanocomposite thin films in the Ti-Pt-C system
    Open this publication in new window or tab >>Carbide and nanocomposite thin films in the Ti-Pt-C system
    Show others...
    2010 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 18, p. 5104-5109Article in journal (Refereed) Published
    Abstract [en]

    Thin films in the Ti-Pt-C system were deposited by non-reactive, DC-magnetron sputtering. Samples were characterised using X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy. A previously not reported metastable solid solution carbide, (Ti1-xPtx)C-y with a Pt/Ti ratio of up to 0.43 was observed. This solid solution phase was present both as single phase in polycrystalline samples, and together with amorphous carbon (a-C) in nanocomposite samples. Annealing of nanocomposite samples leads to the decomposition of the solid solution phase and the formation of a nc-TiCx/a-C/nc-Pt nanocomposite. Test sensors for automotive gas exhausts manufactured from such a three-phase material suffer from complete oxidation of the coating at 400 degrees C with no observed sensor activity.

    Place, publisher, year, edition, pages
    Elsevier B.V., 2010
    Keywords
    Solid solution carbide, Nanocomposite, Sputtering, Gas sensor; Annealing, Transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction
    National Category
    Inorganic Chemistry
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-109234 (URN)10.1016/j.tsf.2010.03.017 (DOI)000279659900013 ()
    Available from: 2009-10-12 Created: 2009-10-12 Last updated: 2017-12-12Bibliographically approved
  • 30.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Nanokompositer - material med nya möjligheter2010Conference paper (Other (popular science, discussion, etc.))
  • 31.
    Lewin, Erik
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Nanostrukturierte Hartstoff-Schichten2012Conference paper (Other (popular science, discussion, etc.))
  • 32.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    On interfacial bonding in carbide based nanocomposites2013Conference paper (Other academic)
  • 33.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    André, Benny
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Urbonaite, Sigita
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Synthesis, structure and properties of Ni-alloyed TiCx-based thin films2010In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 20, no 28, p. 5950-5960Article in journal (Refereed)
    Abstract [en]

    By using non-reactive sputter deposition at low temperatures metastable solid solution phases in the Ti–Ni–C system were synthesized. Produced thin films were either single phase carbides or nanocomposite of nanocrystalline carbide and amorphous C. In the Ni-containing samples a supersaturated solid solution phase (Ti1−xNix)Cy was identified, and was present either as single phase or in a nanocomposite with amorphous C. By modification of the chemical stability of the carbide phase, the addition of Ni was found to strongly promote the formation of amorphous carbon phase in the coatings. Samples have been microstructurally analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Mechanical properties have been evaluated through nanoindentation and pin-on-disc measurements; electrical properties were determined by measurement of the resistivity and the contact resistance. Alloyed nanocomposite coatings were also found to exhibit enhanced tribological and electrical properties, with a decreased resistivity and friction. This makes these thin films very interesting for application in sliding electrical contacts. The mechanisms responsible for the reductions remain to be determined.

  • 34.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Buchholt, Kristina
    Lu, Jun
    Hultman, Lars
    Lloyd Spetz, Annika
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carbide and nanocomposite thin films in the Ti-Pt-C system2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 18, p. 5104-5109Article in journal (Refereed)
    Abstract [en]

    Thin films in the Ti-Pt-C system were deposited by non-reactive, DC-magnetron sputtering. Samples were characterised using X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy. A previously not reported metastable solid solution carbide, (Ti1-xPtx)C-y with a Pt/Ti ratio of up to 0.43 was observed. This solid solution phase was present both as single phase in polycrystalline samples, and together with amorphous carbon (a-C) in nanocomposite samples. Annealing of nanocomposite samples leads to the decomposition of the solid solution phase and the formation of a nc-TiCx/a-C/nc-Pt nanocomposite. Test sensors for automotive gas exhausts manufactured from such a three-phase material suffer from complete oxidation of the coating at 400 degrees C with no observed sensor activity.

  • 35.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Empa, Lab Nanoscale Mat Sci, Uberlandstr 129, CH-8600 Dubendorf, Switzerland.
    Counsell, Jonathan
    Kratos Analyt Ltd, Trafford Wharf Rd, Manchester M17 1G, Lancs, England.
    Patscheider, Jörg
    Empa, Lab Nanoscale Mat Sci, Uberlandstr 129, CH-8600 Dubendorf, Switzerland;Evatec AG, Trubbach, Switzerland.
    Spectral artefacts post sputter-etching and how to cope with them - A case study of XPS on nitride-based coatings using monoatomic and cluster ion beams2018In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 442, p. 487-500Article in journal (Refereed)
    Abstract [en]

    The issue of artefacts due to sputter-etching has been investigated for a group of AlN-based thin film materials with varying thermodynamical stability. Stability of the materials was controlled by alloying AlN with the group 14 elements Si, Ge or Sn in two different concentrations. The coatings were sputter-etched with monoatomic Ar+ with energies between 0.2 and 4.0 keV to study the sensitivity of the materials for sputter damage. The use of Ar-n(+) clusters to remove an oxidised surface layer was also evaluated for a selected sample. The spectra were compared to pristine spectra obtained after in-vacuo sample transfer from the synthesis chamber to the analysis instrument. It was found that the all samples were affected by high energy (4 keV) Ar+ ions to varying degrees. The determining factors for the amount of observed damage were found to be the materials' enthalpy of formation, where a threshold value seems to exist at approximately -1.25 eV/atom (similar to-120 kJ/mol atoms). For each sample, the observed amount of damage was found to have a linear dependence to the energy deposited by the ion beam per volume removed material. Despite the occurrence of sputter-damage in all samples, etching settings that result in almost artefact-free spectral data were found; using either very low energy (i.e. 200 eV) monoatomic ions, or an appropriate combination of ion cluster size and energy. The present study underlines that analysis post sputter-etching must be carried out with an awareness of possible sputter-induced artefacts.

  • 36.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Gorgoi, Mihaela
    Schäfers, Franz
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings2009In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 204, no 4, p. 455-462Article in journal (Refereed)
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) is a standard method of determining chemical bonding in e.g. nanocomposites. We demonstrate that sputter-cleaning of the sample prior to analysis can substantially alter the attained information. We present an in-depth analysis of sputter damage on binary and ternary TiC-based coatings in the Ti–Ni–C system. XPS was performed after sputter etching with different ion energies (0.15–4 keV). Results are compared to data from the bulk of undamaged samples attained using high kinetic energy XPS. We observe substantial sputter damage, strongly dependent on sputter energies and coating stability. Metastable samples exhibit severe sputter damage after etching with 4 keV. Additional samples from other Ti–Me–C (Me = Al, Fe, Cu or Pt) systems were also examined, and notable sputter damage was observed. This suggests that accurate analysis of any metastable nanocomposite requires careful consideration of sputter damages.

  • 37.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    A contact element and a contact arrangement2013Patent (Other (popular science, discussion, etc.))
  • 38.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Gorgoi, M
    Schäfers, F
    Svensson, S
    Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings2009Conference paper (Refereed)
  • 39.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Joelsson, T
    André, B
    Ljungcrantz, H
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Industrialisation study of nanocomposite coatings for electrical contact applications2008Conference paper (Refereed)
  • 40.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Johansson, E
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Sandell, A
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Gorgoi, M
    Schäfers, F
    Braun, W
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Stüber, M
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Svensson, S
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Eberhardt, W
    HIKE experiments at KMC-1: Recent Analysis of Thin Film Nanocomposites2007In: Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung m.b.H. (BESSY) Annual Report (2006), p. 503-504Article in journal (Other academic)
  • 41.
    Lewin, Erik
    et al.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Loch, D
    HIPIMS Technology Centre, MERI, Sheffield Hallam University, UK.
    Ehiasarian, A.P.
    HIPIMS Technology Centre, MERI, Sheffield Hallam University, UK.
    Patscheider, J.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Hard and optically transparent Al-Si-N nanocomposites deposited with HIPIMS and DCMS2011Conference paper (Other academic)
  • 42.
    Lewin, Erik
    et al.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Loch, Daniel
    HIPIMS Technology Centre, MERI, Sheffield Hallam University, UK.
    Montagne, Alex
    Mechanics of Materials and Nanostructures, Empa, Thun, Switzerland.
    Ehiasarian, Arutiun P.
    HIPIMS Technology Centre, MERI, Sheffield Hallam University, UK.
    Patscheider, Joerg
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Comparison of Al-Si-N nanocomposite coatings deposited by HIPIMS and DC magnetron sputtering2013In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 232, p. 680-689Article in journal (Refereed)
    Abstract [en]

    This paper presents a comparative study between DC magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HIPIMS) of Al-Si-N. Coatings were synthesised through co-sputtering of Al and Si in a mixed Ar/N-2. One set of DCMS experiments and one set of hybrid HIPIMS (Al-target)/DCMS (Si-target) experiments were conducted. It was found that a higher partial pressure of N-2 was necessary to obtain fully nitrided material using the HIPIMS process. The Si content of the samples was varied between 0 and 16 at.%. All processes were characterised using optical emission spectroscopy (OES) as well as energy-resolved mass spectrometry (E-MS). The obtained coatings were characterised using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), as well as UV-Vis spectroscopy and nanoindentation. The HIPIMS processes were found to provide a highly activated growth environment, with Al+ comprising 87% of the total ion flux, compared to 0.6% for the DCMS case, where Ar+ was found to be the dominating species comprising 90% of the total ion flux. Coatings from both HIPIMS and DCMS processes were found to form nanocomposites of a solid solution phase (Al1-xSix)N and most likely a SiN, phase, as shown by XRD and XPS analyses. Compared to coatings from DCMS, samples deposited with HIPIMS had a slightly more textured AlN-phase with smaller grains, as well as smoother and, denser morphology as observed by SEM. In agreement with previous studies, the coatings had a high transparency in the visual and near IR range; an optical band gap (E-04) between 4.6 and 5.2 eV and a refractive index between 1.9 and 2.1 was observed. The ternary coatings studied here were found to be hard with the HIPIMS coatings (combined average 22 +/- 3 GPa) being harder than their DCMS counterpart (combined average 17 +/- 1 GPa). A maximum hardness of 27 GPa was observed for the sample deposited with HIPIMS and a Si-content of 7 at.%.

  • 43.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Olsson, Erik
    André, Benny
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Joelsson, Torbjörn
    Öberg, Åke
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ljungcrantz, Henrik
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Industrialisation Study of Nanocomposite nc-TiC/a-C Coatings for Electrical Contact Applications2009In: Plasma Processes and Polymers, ISSN 1612-8850, Vol. 6, no S1, p. S928-S934Article in journal (Refereed)
    Abstract [en]

    Nanocomposite nc-TiC/a-C coatings were prepared by non-reactive magnetron sputtering in industrial scale equipment, under varying deposition conditions in order to investigate upscaling and possible industrialisation. The coatings were found to have similar microstructure and performance compared to previous laboratory scale experiments. The samples were characterised with XRD, XPS and SEM as well with ball-on-disc, nanoindentation and electrical measurements. Coatings containing a small fraction of a-C matrix phase were found to have promising both electrical properties (rho < 400 mu Omega cm and contact resistances down to 0.34 m Omega at 40 N) and tribological properties (f < 0.3 for 10 000 laps).

  • 44.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Parlinska-Wojtan, M.
    Electron microscopy centrum, Empa, Dübendorf, Switzerland.
    Patscheider, J.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Alloying AlN with Ge or Sn: optically transparent hard nanocomposite coatings with variable absorption edge2013Conference paper (Other academic)
  • 45.
    Lewin, Erik
    et al.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Parlinska-Wojtan, M.
    Electron microscopy centrum, Empa, Dübendorf, Switzerland.
    Patscheider, J.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Nanocomposte coatings in the Al-Ge-N system: synthesis, structure and mechanical and optical properties2012Conference paper (Other academic)
  • 46.
    Lewin, Erik
    et al.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland .
    Parlinska-Wojtan, Magdalena
    Electron microscopy centre, Empa, Dübendorf, Switzerland .
    Patscheider, Joerg
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland .
    Nanocomposite Al-Ge-N thin films and their mechanical and optical properties2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 33, p. 16761-16773Article in journal (Refereed)
  • 47.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Patscheider, J.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Ion Beam Induced Damages on Metastable Nitride Coatings2014Conference paper (Other academic)
  • 48.
    Lewin, Erik
    et al.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Patscheider, J.
    Laboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland.
    Reactively sputtered Al-Sn-N nanocomposite coatings2012Conference paper (Other academic)
  • 49.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Patscheider, Jörg
    aboratory for Nanoscale Materials Science, Empa, Dübendorf, Switzerland..
    Controlling Mechanical and Optical Properties by Alloying: Ternary and Quaternary Oxynitride Coating2015Conference paper (Other academic)
  • 50.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Empa, Lab Nanoscale Mat Sci, Uberlandstr 129, CH-8600 Dubendorf, Switzerland..
    Patscheider, Jörg
    Empa, Lab Nanoscale Mat Sci, Uberlandstr 129, CH-8600 Dubendorf, Switzerland..
    Structure and properties of sputter-deposited Al-Sn-N thin films2016In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 682, p. 42-51Article in journal (Refereed)
    Abstract [en]

    Coatings consisting of Al, Sn and N have been deposited using co-sputtering from Al and Sn targets in a reactive atmosphere containing N-2. AlN was used as starting point, and the Sn content was gradually increased through higher cathode power on the Sn target, resulting in coatings with Sn-contents between 0 and 24 at.%. The coatings were analysed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) and also characterised using UV-vis spectroscopy and nanoindentation. All coatings show a nitrogen content of about 50 at.% and are thus fully nitrided, which is confirmed by bonding analysis with XPS. A combination of results from XRD and XPS leads to the conclusion that the coatings consist of a single phase solid solution based on wurzite (Al1-xSnx) N-y with x varying between 0 and 0.5, and y close to unity. The attained material is metastable with respect to decomposition into AlN, Sn and N-2, as shown by sputter damages occurring during Ar+ ion etching. The top surface and cross sections, as observed in SEM, were found to become smoother and the columnar structure less pronounced, changing to grainy and finally glass like morphology, as the Sn content is increased. The material is hard at room temperature, with nanoindentation values of 17-24 GPa. Coatings on silica substrates are transparent and yellow to red-brown in colour. This is quantified as a shifting absorption edge, which moves from 211 to 510 nm, corresponding to an optical band gap of 5.9 and 2.4, respectively, as the Sn-content is increased. The index of refraction varies between 2.0 and 2.6. The deposited materials are thus hard, and have a tuneable absorption edge, which could be applicable in optical applications as a multifunctional optical filter with scratch resistant properties.

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