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Heinrichs, Jannica
Publications (10 of 48) Show all publications
Roizard, X., Heinrichs, J., Buteri, A., Jacobson, S., Borgeot, M., Carpentiar, L., . . . Lallemand, F. (2018). Friction behavior of ferritic stainless steel in a strongly diluted alcohol solution of alkylphosphonic acid. Paper presented at 17th Nordic Symposium on Tribology (NORDTRIB), JUN 14-17, 2016, Hameenlinna, FINLAND. Tribology International, 118, 465-473
Open this publication in new window or tab >>Friction behavior of ferritic stainless steel in a strongly diluted alcohol solution of alkylphosphonic acid
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2018 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 118, p. 465-473Article in journal (Refereed) Published
Abstract [en]

The present study investigates the potential for using this more environmentally friendly lubrication at an industrial scale forming of stainless steel. Against this background we analyze the characteristics of the tribofilm formed on a stainless steel surface during sliding experiments performed in solutions containing alkylphosphonic acids, under various contact conditions. Specific tribological tests were designed to analyze the dynamics of the lubricating mechanism. It was found that both the grafting of molecules and the transformation of these into an efficient tribofihn are quick processes, irrespective of substrate roughness or contact pressure, systematically leading to low friction coefficient.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2018
Keywords
Stainless steel, Forming, Low friction, Phosphonic acids
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-343790 (URN)10.1016/j.triboint.2017.04.027 (DOI)000423004700047 ()
Conference
17th Nordic Symposium on Tribology (NORDTRIB), JUN 14-17, 2016, Hameenlinna, FINLAND
Funder
Swedish Research Council, 2009-15941-70482-35
Available from: 2018-03-07 Created: 2018-03-07 Last updated: 2018-03-07Bibliographically approved
Roizard, X., Heinrichs, J., Buteri, A., Jacobson, S., Borgeot, M., Carpentiar, L., . . . Lallemand, F. (2018). Friction behavior of ferritic stainless steel in a strongly diluted alcohol solution of alkylphosphonic acid. Paper presented at 17th Nordic Symposium on Tribology (NORDTRIB), JUN 14-17, 2016, Hameenlinna, FINLAND. Tribology International, 118, 465-473
Open this publication in new window or tab >>Friction behavior of ferritic stainless steel in a strongly diluted alcohol solution of alkylphosphonic acid
Show others...
2018 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 118, p. 465-473Article in journal (Refereed) Published
Abstract [en]

The present study investigates the potential for using this more environmentally friendly lubrication at an industrial scale forming of stainless steel. Against this background we analyze the characteristics of the tribofilm formed on a stainless steel surface during sliding experiments performed in solutions containing alkylphosphonic acids, under various contact conditions. Specific tribological tests were designed to analyze the dynamics of the lubricating mechanism. It was found that both the grafting of molecules and the transformation of these into an efficient tribofihn are quick processes, irrespective of substrate roughness or contact pressure, systematically leading to low friction coefficient.

Keywords
Stainless steel, Forming, Low friction, Phosphonic acids
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-343657 (URN)10.1016/j.triboint.2017.04.027 (DOI)000423004700047 ()
Conference
17th Nordic Symposium on Tribology (NORDTRIB), JUN 14-17, 2016, Hameenlinna, FINLAND
Available from: 2018-05-09 Created: 2018-05-09 Last updated: 2018-05-09Bibliographically approved
Elo, R., Heinrichs, J. & Jacobson, S. (2018). Surface texturing to promote formation of protective tribofilms on combustion engine valves. Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, 232(1), 54-61
Open this publication in new window or tab >>Surface texturing to promote formation of protective tribofilms on combustion engine valves
2018 (English)In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 232, no 1, p. 54-61Article in journal (Refereed) Published
Abstract [en]

In a combustion engine, the valve system controls the flow of gases in to and out of the combustion chamber.The contacting surfaces experience a harsh tribological situation with high temperatures, high speed impacts, corrosiveenvironment and high closing forces causing micro sliding in the interface. The components have to endure in the rangeof hundreds of millions to a billion operational cycles, resulting in extreme demands on low wear rate. Such low wearrates can be accomplished by the protective action from tribofilms forming from oil residues, avoiding a pure metal-tometalcontact. Such tribofilms are found on well-functioning engine valves from a variety of engines, but some stationarygas engines experience problems with wear occurring seemingly randomly at normal running conditions. For somereason, the tribofilm has not protected the surfaces sufficiently, causing wear. One way to combat the random behaviourcould be to promote robust function of the protective tribofilms by texturing the valve sealing surfaces to improve thecapture and storage of oil residues. By stabilising the supply in this way, the damage from periods with low access totribofilm forming material could be reduced. The present work demonstrates that turning of the valve seat inserts,creating valleys perpendicular to the sliding motion, can be developed into a useful solution. The amount and localisationof tribofilms became more predictable and stable than without the texture, leading to reduced component wear. Thevalleys should not be too wide, since this increased the amount of exposed metal if the tribofilm flaked off. When havingthe same width, the deeper valleys showed less flaking off of the tribofilm.

Keywords
Tribofilm formation, combustion engine valve, surface texture, rig testing, scanning electron microscopy
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-335323 (URN)10.1177/1350650117739738 (DOI)000419852700006 ()
Available from: 2017-12-04 Created: 2017-12-04 Last updated: 2018-02-22Bibliographically approved
Heinrichs, J., Olsson, M. & Jacobson, S. (2017). Initial deformation and wear of cemented carbides in rock drilling as examined by a sliding wear test. INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, 64, 7-13
Open this publication in new window or tab >>Initial deformation and wear of cemented carbides in rock drilling as examined by a sliding wear test
2017 (English)In: INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, ISSN 0263-4368, Vol. 64, p. 7-13Article in journal (Refereed) Published
Abstract [en]

Due to a combination of high hardness and toughness, resulting in excellent wear resistance, cemented carbides are commonly used as the rock crushing component in rock drilling. The present paper presents a unique study where the very initial stages of deformation and wear of cemented carbide in sliding contact with rock are followed in small incremental steps. After each step, a pre-determined area within the wear mark is characterized using high resolution SEM and EDS. This facilitates analysis of the gradual deformation, material transfer, degradation and wear. The deterioration mechanisms found in this sliding test are similar to those observed in actual rock drilling. Cemented carbide grades with different microstructures show significant differences, where a higher amount of Co and a larger WC grain size both are associated to more wear.

Keywords
Cemented carbides, Sliding, Wear, Deformation, Granite, Rock drilling
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-321423 (URN)10.1016/j.ijrmhm.2016.12.011 (DOI)000397364600002 ()
Available from: 2017-05-16 Created: 2017-05-16 Last updated: 2017-05-16Bibliographically approved
Olsson, M., Yvell, K., Heinrichs, J., Bengtsson, M. & Jacobson, S. (2017). Surface degradation mechanisms of cemented carbide drill buttons in iron ore rock drilling. Paper presented at 17th Nordic Symposium on Tribology (NORDTRIB), JUN 14-17, 2016, Hameenlinna, FINLAND. Wear, 388-389, 81-92
Open this publication in new window or tab >>Surface degradation mechanisms of cemented carbide drill buttons in iron ore rock drilling
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2017 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 388-389, p. 81-92Article in journal (Refereed) Published
Abstract [en]

The wear behavior of cemented carbide rock drill buttons is influenced by many factors, which include the composition and microstructure of the cemented carbide material, the nature of the rock material, and the conditions of the rock drilling operation. Depending on the type of rock and on the drilling procedure used, the cemented carbide is exposed to substantially differing mechanical and thermal conditions. In the present study, the surface degradation and wear mechanisms of cemented carbide drill buttons exposed to iron ore rock drilling have been characterized based on a combination of high resolution scanning electron microscopy (SEM), focused ion beam cross-sectioning (FIB), energy-dispersive X-ray spectroscopy (EDS) and electron back scatter diffraction (EBSD). The results show a significant difference in surface degradation and wear between the front and peripheral buttons of the drill bits. While the front buttons display a relatively smooth worn surface with shallow surface craters the peripheral buttons display a reptile skin pattern, i.e. plateaus, 200-300 gm in diameter, separated by valleys, typically 40-50 gm wide and 15-30 gm deep, The reptile skin pattern is obtained in regions where the peripheral buttons are in sliding contact against the drill hole walls and exposed to high surface temperatures caused by the frictional heating. The results indicate that the reptile skin pattern is related to friction induced thermal stresses rather than mechanical contact stresses, i.e. the reptile skin pattern is formed due to thermal fatigue, rather than mechanical fatigue, caused by the cyclic frictional heating generated at the cemented carbide button/iron ore interface.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2017
Keywords
Cemented carbide, Rock drilling, Iron ore, Reptile skin, Wear mechanisms
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-337108 (URN)10.1016/j.wear.2017.03.004 (DOI)000412614900010 ()
Conference
17th Nordic Symposium on Tribology (NORDTRIB), JUN 14-17, 2016, Hameenlinna, FINLAND
Funder
Knowledge Foundation, 20150193
Available from: 2017-12-20 Created: 2017-12-20 Last updated: 2017-12-20Bibliographically approved
Elo, R., Heinrichs, J. & Jacobson, S. (2017). Wear protective capacity of tribofilms formed on combustion engine valves with different surface textures. Wear, 376-377, 1429-1436
Open this publication in new window or tab >>Wear protective capacity of tribofilms formed on combustion engine valves with different surface textures
2017 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376-377, p. 1429-1436Article in journal (Refereed) Published
Abstract [en]

The valve system controls the flow of gases into and out of the cylinders of combustion engines. As the combustion chamber is repeatedly filled with air and emptied from combustion residues, the contacting surfaces of the valve and valve seat insert (VSI) are exposed to high temperatures, high speed impacts, corrosive environment and high closing forces. Since the expected wear life of the components is hundreds of millions of operational cycles, the wear rate has to be extremely low. Previous studies have shown that this is accomplished by the continual formation of protective tribofilms on the surfaces, formed from oil additive residues. For some stationary gas engines, seemingly random occurrence of severe wear, i.e. without correlation to special running conditions, calls for an improved understanding of the wear protective abilities of these tribofilms. Further, the potential of making the protection more robust by using simple textures on sealing surfaces is investigated. Real valves and VSI's were therefore run in a dedicated test rig, previously shown capable of forming tribofilms similar to those found in real engine valves. Two surface textures, turned or ground, were tested. After a running in phase where fully covering tribofilms were formed, the tests were continued without adding the oil residues needed for replenishing the tribofilm. The flow of oil residues was either completely stopped or only intermittently open. The resulting wear was monitored during testing and after finishing the tests remaining tribofilms were analysed with SEM and EDS. The severity of the wear was graded and the presence of tribofilm and localization of wear was correlated. The endurance of the tribofilms was surprisingly high for both textures. Typically the tribofilms exhibited better wear resistance than the underlying metals. Once fully formed, the tribofilms can therefore endure for a long time without addition of new tribofilm forming material. Both textures showed the first sign of wear after roughly the same time and then followed the same progression, when the flow of oil residues was cut. With the intermittent oil residue supply, both textures performed even better. Especially the turned texture showed only slow, mild wear.

Keywords
Combustion engine valves, Surface texturing, Protective tribofilms, Rig testing
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-329132 (URN)10.1016/j.wear.2016.12.060 (DOI)000403902000057 ()
Available from: 2017-10-10 Created: 2017-10-10 Last updated: 2018-02-22
Roizard, X., Heinrichs, J., Taouil, A. E., Jacobson, S., Olsson, M., Melot, J. M. & Lallemand, F. (2016). Insights into sliding wear and friction behavior of copper in ethanol containing alkylphosphonic acid molecules. Tribology International, 96, 141-148
Open this publication in new window or tab >>Insights into sliding wear and friction behavior of copper in ethanol containing alkylphosphonic acid molecules
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2016 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 96, p. 141-148Article in journal (Refereed) Published
Abstract [en]

In this work, the friction and wear behavior of bare copper was investigated for the first time under lubricated sliding conditions in diluted ethanol solutions of butylhosphonic (C4P), octylphosphonic (C8P), dodecylphosphonic (C12P), and hexadecylphosphonic (C16P) acids. The technique aims towards a more environmentally friendly lubrication to be used in shaping of copper sheets. Bare copper samples were subjected to unidirectional sliding using a tribometer with ball-on-disk contact geometry. Copper substrates (20 mm(2) x 1 mm) were run against 100Cr6 empty set10 mm ball bearing counterbodies. All tests were conducted using the same sliding conditions with a normal load of 10 N, tangential velocity of 0.01 m/s, at room temperature of 20 degrees C. Worn surfaces were analyzed by Scanning Electron Microscopy, Optical Microscopy and White Light Interference Profilometry. When comparing to sliding tests in the pure ethanol solvent, significant decreases in terms of wear track dimensions, transferred material on the ball and friction coefficients are observed when active molecules are present in the solution. These form protective tribofilms exhibiting lubricating and anti-wear properties. Deeper studies on the tribological behavior of copper in C4P solution show that both low friction and low transfer of work material to the ball prevail in a specific range of low molecule concentration (5 x 10(-4) M; 25 x 10(-4) M). Even if the molecules are introduced during the test, after a few cycles, the tribological behavior improves, regardless of both friction level and copper surface degradation. Finally, specific friction tests were performed to further investigate the mechanisms. It was found that two mechanisms are involved; firstly molecules grafting onto the surface directly reduces friction, and secondly transformation of these grafted molecules into a tribofilm during the first mechanical contact cycles reduces it even further.

Keywords
Lubricated, Additives, Low friction, Phosphonic acids
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-282283 (URN)10.1016/j.triboint.2015.12.040 (DOI)000371100800013 ()
Funder
Swedish Research Council, 2009-15941-70482-35
Available from: 2016-04-05 Created: 2016-04-05 Last updated: 2017-11-30Bibliographically approved
Westlund, V., Heinrichs, J., Olsson, M. & Jacobson, S. (2016). Investigation of material transfer in sliding friction-topography or surface chemistry?. Tribology International, 100, 213-223
Open this publication in new window or tab >>Investigation of material transfer in sliding friction-topography or surface chemistry?
2016 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 100, p. 213-223Article in journal (Refereed) Published
Abstract [en]

To differentiate between the roles of surface topography and chemical composition on influencing friction and transfer in sliding contact, a series of tests were performed in situ in an SEM. The initial sliding during metal forming was investigated, using an aluminum tip representing the work material, put into sliding contact with a polished flat tool material. Both DLC-coated and uncoated tool steel was used. By varying the final polishing step of the tool material, different surface topographies were obtained. The study demonstrates the strong influence from nano topography of an unpolished DLC coated surface on both coefficient of friction and material transfer. The influence of tool surface chemistry is also discussed.

Keywords
Sliding, Topography, Coating, Transfer
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-300443 (URN)10.1016/j.triboint.2016.01.022 (DOI)000379279600025 ()
External cooperation:
Funder
Swedish Research Council, 621-2013-5858
Available from: 2016-08-09 Created: 2016-08-09 Last updated: 2018-03-21Bibliographically approved
Heinrichs, J., Olsson, M. & Jacobson, S. (2015). Initial deformation and wear of cemented carbides for rock drilling as evaluated by a sliding wear test. In: : . Paper presented at International Tribology Congress, September 16-20, Tokyo, Japan.
Open this publication in new window or tab >>Initial deformation and wear of cemented carbides for rock drilling as evaluated by a sliding wear test
2015 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-264112 (URN)
Conference
International Tribology Congress, September 16-20, Tokyo, Japan
Available from: 2015-10-05 Created: 2015-10-05 Last updated: 2016-04-20
Olsson, M., Heinrichs, J., Yvell, K. & Jacobson, S. (2015). Initial degradation of cemented carbides for rock drilling - Model studies of the tribological contact against rock. International journal of refractory metals & hard materials, 52, 104-113
Open this publication in new window or tab >>Initial degradation of cemented carbides for rock drilling - Model studies of the tribological contact against rock
2015 (English)In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, ISSN 0263-4368, Vol. 52, p. 104-113Article in journal (Refereed) Published
Abstract [en]

Hardness and fracture toughness are often used as the prime material parameters to characterise cemented carbides used in rock drilling. However, the deformation and wear of cemented carbide are too complicated to be described by these parameters alone. The cemented carbide and the wearing rock mineral are both composite materials, containing phases with widely varying hardness. Moreover, the deformation behaviour of the individual phases may be strongly anisotropic, as for the WC grains in the cemented carbide. The wear of the cemented carbide typically occurs on the scale of individual grains or smaller. Contrastingly, the hardness stated for both is typically a macroscopic value, averaged over numerous grains, orientations, etc. The present investigation aims to contribute to the understanding of the relations between microstructure, properties and wear mechanisms of cemented carbide buttons in rock drilling. It is focused on the role of scale of deformation in relation to size of the different phases of the cemented carbide. This is achieved by simplifying the contact situation of the rock drill button to a single stylus sliding contact between a granite stylus and a polished cemented carbide surface. The deformation and wear of this well controlled contact is then evaluated on the sub-micrometer scale; using high resolution FEG-SEM with EBSD, FIB cross-sectioning and AFM. The results show that even an extremely local deformation, such as slip within individual WC grains, affects the tribological contact, and that the nominally much softer granite may cause deformation both within individual WC grains, and on the composite scale. The results are discussed with respect to their significance for wear of cemented carbides in rock drilling.

Keywords
Sliding contact, Granite stylus, Cemented carbide, Transfer, Initial degradation, Rock drilling
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-260802 (URN)10.1016/j.ijrmhm.2015.05.019 (DOI)000358625500017 ()
Funder
Swedish Foundation for Strategic Research , RMA08-0019
Available from: 2015-08-31 Created: 2015-08-25 Last updated: 2017-12-04Bibliographically approved
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