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Jacobson, Staffan, Prof.ORCID iD iconorcid.org/0000-0002-3955-5746
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Publications (10 of 214) 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
Keyword
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.

Keyword
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.

Keyword
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
Larsson, E., Olander, P. & Jacobson, S. (2017). Boric acid as a lubricating fuel additive - Simplified lab experiments to understand fuel consumption reduction in field test. Paper presented at 21st International Conference on Wear of Materials (WOM), MAR 26-30, 2017, Long Beach, CA, USA. Wear, 376, 822-830
Open this publication in new window or tab >>Boric acid as a lubricating fuel additive - Simplified lab experiments to understand fuel consumption reduction in field test
2017 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376, p. 822-830Article in journal (Refereed) Published
Abstract [en]

In field tests, a boric acid based fuel additive has led to reduced fuel consumption. The reduction was substantial, an average of 6 and 10% in passenger cars and diesel generators respectively. Aiming towards improved understanding of mechanisms behind the fuel saving, three methods to mimic the effect of the additive in the piston-ring/cylinder contact have been evaluated. A reciprocating cylinder/flat configuration with ball bearing steel against grey cast iron was used, and it was lubricated with base oil. The different methods were as following: A) repeated spraying of a small amount of the boric acid solution onto the surfaces, B) predeposition of a boric acid layer on the flat surface and C) a combination of method A) and B). The three methods all showed effects of the additive, spanning from about 20% to 50% reductions (in the latter case, from roughly 0.1 to 0.05 in coefficient of friction averaged over the stroke). The greatest potential of the additive was seen with local coefficient of frictions lower than 0.020 in tests at room temperature with Method C. This means a reduction of around 75% compared to the lowest levels measured for the reference tests run without the additive. The most stable friction test was Method A, where a small amount of boric acid solution was repeatedly sprayed onto the lubricated sliding surfaces. In this type of test, friction reductions of roughly 20% and 40% were found at 100 C and room temperature respectively. The tribological and chemical mechanisms of boric acid in this test configuration are yet not fully understood and more studies are needed. However, the observed poor stability of the tribofilms containing boron and oxygen complicates such activities.

Keyword
Boric acid, Lubrication, Friction, Fuel consumption, Fuel additive
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-329131 (URN)10.1016/j.wear.2017.01.105 (DOI)000403904000093 ()
Conference
21st International Conference on Wear of Materials (WOM), MAR 26-30, 2017, Long Beach, CA, USA
Funder
VINNOVA
Available from: 2017-10-10 Created: 2017-10-10 Last updated: 2017-11-29Bibliographically approved
Larsson, E., Olander, P. & Jacobson, S. (2017). Boric acid as a lubricating fuel additive: Optimization of a lab test to understand fuel consumption reduction in field tests. In: : . Paper presented at Society of tribologists and lubrication engineers (STLE) 72nd Annual Meeting & Exhibition, 21–25 May 2017, Atlanta, Georgia, USA (pp. 1-1).
Open this publication in new window or tab >>Boric acid as a lubricating fuel additive: Optimization of a lab test to understand fuel consumption reduction in field tests
2017 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-330470 (URN)
Conference
Society of tribologists and lubrication engineers (STLE) 72nd Annual Meeting & Exhibition, 21–25 May 2017, Atlanta, Georgia, USA
Available from: 2017-09-29 Created: 2017-09-29 Last updated: 2017-12-29Bibliographically approved
Aiso, T., Wiklund, U., Kubota, M. & Jacobson, S. (2017). Effect of combined additions of Si, Mn, Cr and Al to carbon steel on material transfer in a steel/TiN coated tool sliding contact. Paper presented at NORDTRIB 2016: The 17th Nordic Symposium on Tribology,14th - 17th June 2016 - Aulanko, Hämeenlinna, Finland. Wear, 388-389, 9-17
Open this publication in new window or tab >>Effect of combined additions of Si, Mn, Cr and Al to carbon steel on material transfer in a steel/TiN coated tool sliding contact
2017 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 388-389, p. 9-17Article in journal (Refereed) Published
Abstract [en]

Material transferred from steel work materials onto the cutting tools largely affects tool life and machining performance. This material transfer is strongly influenced by the steel composition, and different alloying can have very different effects. Crossed cylinders sliding tests can be used to simulate the contact between the chip and the tool in machining. In this work such a test is used to evaluate material transfer and friction characteristics of a TiN coated tool sliding against five model steels. These model steels are especially designed to study the effects from specific combination of alloy elements, i.e. the steels, containing 0.55 mass% C and 1 mass% Si, are alloyed with one or more of 1 mass% Mn, Cr and Al. When using the steels alloyed without Al, Si-rich oxide layers are formed on the coating, resulting in a low friction coefficient. When using the steels alloyed with Al, almost pure Al–O layers are formed, resulting in a higher friction coefficient and rapid coating cracking. Essentially, the most easily oxidized alloy element is most strongly enriched in the oxide and decides the main mechanism of the material transfer and friction behavior.

Keyword
Sliding, Steel, PVD coatings, Cutting tools, Transfer
National Category
Materials Engineering
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-306189 (URN)10.1016/j.wear.2017.04.028 (DOI)000412614900003 ()
Conference
NORDTRIB 2016: The 17th Nordic Symposium on Tribology,14th - 17th June 2016 - Aulanko, Hämeenlinna, Finland
Available from: 2016-10-26 Created: 2016-10-26 Last updated: 2017-12-22Bibliographically 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.

Keyword
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
Toller, L., Jacobson, S. & Norgren, S. (2017). Life time of cemented carbide inserts with Ni-Fe binder in steel turning. Wear, 376, 1822-1829
Open this publication in new window or tab >>Life time of cemented carbide inserts with Ni-Fe binder in steel turning
2017 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376, p. 1822-1829Article in journal (Refereed) Published
Abstract [en]

Health concerns associated with cobalt powder are a strong motivator for conducting research on alternative binders for cemented carbides. It has previously been shown possible to make cemented carbides with alternative binders, which offer good hardness and toughness. However, it is not fully known if these cemented carbides can be successfully used as metal cutting tools. In this study we have tested turning inserts from cemented carbide with a nickel-iron binder and compared these with cobalt based reference inserts in dry face turning of steel in a pairwise comparison. To facilitate relevant comparisons, both the alternative binder and the reference cemented carbide are gradient sintered and coated in the same way as commercial turning grades. It is found that the life time in this dry face turning test is only approximately 15% shorter with the nickel-iron binder than with the cobalt reference, which motivates further studies with this alternative binder. Flaking of the coating and thus less coating adhesion was identified as one reason for the shorter life time.

Keyword
Cutting tools, Cemented carbide, Alternative binder, Face turning
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-329133 (URN)10.1016/j.wear.2017.02.018 (DOI)000403902000097 ()
Funder
VINNOVA
Available from: 2017-10-10 Created: 2017-10-10 Last updated: 2017-10-27Bibliographically 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
Keyword
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.

Keyword
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
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3955-5746

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