Friction and wear performance of diamond-like carbon films grown in various source gas plasmas

Erdemir, Ali; Nilufer, I.B.; Eryilmaz, O. L.; Beschliesser, M.; Fenske, G.R.

doi:10.1016/s0257-8972(99)00444-2

Cited by 76 publications

(29 citation statements)

References 40 publications

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“…The amorphous carbon coatings were deposited from a mixture of methane and hydrogen gas plasma. By varying the ratio of hydrogen to methane, the properties and tribological behavior of the carbon coating can be controlled [3]. The three variations of the carbon coatings evaluated in the present study and some of their properties are shown in Table 1.…”

Section: Methodsmentioning

confidence: 99%

“…One possible means is surface modification of lubricated components, which can be done by coatings and other methods. Amorphous carbon coatings with exceptional friction and wear properties were recently developed at Argonne National Laboratory (ANL) [1][2][3]. The coatings have shown promise in mitigating tribological problems associated with low-lubricity diesel fuels.…”

Section: Introductionmentioning

confidence: 99%

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Friction and Wear Performance of Low-Friction Carbon Coatings Under Oil Lubrication

Kovalchenko¹,

Ajayi²,

Erdemir³

et al. 2002

SAE Technical Paper Series

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Abstract:Amorphous carbon coatings with very low friction properties were recently developed at Argonne National Laboratory. These coatings have shown good promise in mitigating excessive wear and scuffing problems associated with low-lubricity diesel fuels. To reduce the negative effect of sulfur and other lubricant additives in poisoning the after-treatment catalyst, a lubricant formulation with a low level of sulfur may be needed. Exclusion of proven sulfur-containing extreme pressure (EP) and antiwear additives from oils will require other measures to ensure durability of critical lubricated components. The low-friction carbon coating has the potential for such applications. In the present study, we evaluated the friction and wear attributes of three variations of the coating under a boundary lubrication regime. Tests were conducted with both synthetic and mineral oil lubricants using a ball-on-flat contact configuration in reciprocating sliding. Although the three variations of the coating provided modest reductions in friction coefficient, they all reduced wear substantially compared to an uncoated surface.The degradation mode of oxidative wear on the uncoated surface was replaced by a polishing wear mode on the coated surfaces.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Friction and Wear Performance of Low-Friction Carbon Coatings Under Oil Lubrication

Kovalchenko¹,

Ajayi²,

Erdemir³

et al. 2002

SAE Technical Paper Series

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“…Further studies explored the effect of source gases on tribological properties. 31,32,33 Later, high-temperature chlorination of silicon carbide was explored as a route towards DLC film creation, resulting in a disordered graphitic surface layer. …”

Section: Deposition Processmentioning

confidence: 99%

Near-frictionless carbon coatings for spark-ignited direct-injected fuel systems. Final report, January 2002.

Hershberger¹,

Öztürk²,

Ajayi³

et al. 2002

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EXECUTIVE SUMMARYThis report describes an investigation by the Tribology Section of Argonne National Laboratory (ANL) into the use of near-frictionless carbon (NFC) coatings for spark-ignited, direct-injected (SIDI) engine fuel systems. Direct injection is being pursued in order to improve fuel efficiency and enhance control over, and flexibility of, spark-ignited engines. SIDI technology is being investigated by the Partnership for a New Generation of Vehicles (PNGV) as one route towards meeting both efficiency goals and more stringent emissions standards. Argonne's approach to these friction and wear issues was to investigate the applicability of NFC to fuel system parts. In collaboration with Delphi Automotive Systems and BP Amoco plc, Argonne carried out two tasks: optimize the deposition of NFC onto standard flats and balls as well as production fuel injectors, and perform both industry-standard lubricity tests and customized wear tests designed to simulate the engine environment. These tests were performed with several gasolines and other fuels, and the NFC performance was compared to that of uncoated parts and other commercially available coatings, all applied to production fuel injectors. Finally, to understand the wear mechanisms, Argonne applied advanced characterization techniques to the worn and unworn coatings, the steel against which they wore, and the wear debris. The industry-standard lubricity tests included the Falex ball-on-three-disc (BOTD) test, while the customized wear testing was performed in a sealed reciprocating system designed to perform fretting wear tests. Long-duration reciprocating tests were performed with a ii total sliding distance of 2 km in order to determine the steady-state performance of the NFC coatings. The worn surfaces were examined by 3D optical profilometry to determine wear rates.The advanced characterization methods applied included Raman spectroscopy and laser scanning measurement of residual stresses in the NFC coatings.In the customized reciprocating tests, comparisons between two varieties of NFC and three commercially available diamondlike carbon (DLC) coatings showed that the NFCs gave consistently high performance and were generally the best choice for reducing friction and wear, although one of the commercial DLCs achieved performance comparable to the NFCs in several individual tests. The other commercial DLCs displayed poor performance under certain conditions. In dry or ethanol-lubricated wear, NFC6 performed the best; when subjected to E85 or M85 fuel, the commercial DLC gave the best results; and NFC2 displayed the lowest friction and wear rate of the three in regular gasoline, the most relevant condition for fuel injector applications. NFC2 reduced friction in all the liquids tested, compared to tests of uncoated materials in the same fluids; NFC6 did also but not to as great an extent.The long-duration tests designed to determine the ultimate wear lifetime of the NFC coatings on injectors in current-and next-generation gasolines showed that NFC6 pro...

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“…Among others, oxygen and water molecules have the greatest effect on friction of both hydrogenated and hydrogenfree DLC films. For example, in dry air and inert gases, friction coefficients of 0.001-0.05 appear feasible with hydrogenated DLC films [8,12,14,15,[27][28][29][30]. However, in humid air, the friction coefficients may increase to more than 0.1.…”

Section: Major Causes Of Friction In Carbon Filmsmentioning

confidence: 99%

“…In fact, the systematic studies on carbon-based materials and coatings in our laboratory since the late 1980s have led to the discovery of amorphous carbon films that provide extremely low friction and wear coefficients 5 [8][9][10][11][12][13][14][15]. One of the films that we optimized over the years provided friction and wear coefficients of 0.001 to 0.005 and 10 -11 to 10 -10 mm 3 /N.m, respectively, when tested in inert gases or high vacuum [14,15,16].…”

Section: Introductionmentioning

confidence: 99%

Superlubricity and Wearless Sliding in Diamondlike Carbon Films

Erdemir

2001

MRS Proc.

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Diamondlike carbon (DLC) films have attracted great interest in recent years mainly because of their unusual optical, electrical, mechanical, and tribological properties. Such properties are currently being exploited for a wide range of engineering applications including magnetic hard disks, gears, sliding and roller bearings, scratch resistant glasses, biomedical implants, etc. Systematic studies on carbon-based materials in our laboratory have led to the development of a new class of amorphous DLC films that provide extremely low friction and wear coefficients of 0.001 to 0.005 and 10 -11 to 10 -10 mm 3 /N.m, respectively, when tested in inert-gas or high-vacuum environments. These films were produced in highly hydrogenated gas discharge plasmas by a plasma enhanced chemical vapor deposition process at room temperature. The carbon source gases used in the deposition of these films included methane, acetylene, and ethylene. Tribological studies in our laboratory have established a very close correlation between the composition of the plasmas and the friction and wear coefficients of the resultant DLC films. Specifically, the friction and wear coefficients of DLC films grown in plasmas with higher hydrogen-tocarbon ratios were much lower than films derived from source gases with lower hydrogento-carbon ratios. Fundamental tribological and surface analytical studies have led us to conclude that hydrogen (within the film, as well as on the sliding surfaces) is extremely 3 important for the superlubricity and wearless sliding behavior of these films. Based on these studies, a mechanistic model is proposed to explain the superlow friction and wear properties of the new DLC films.

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Friction and wear performance of diamond-like carbon films grown in various source gas plasmas

Cited by 76 publications

References 40 publications

Friction and Wear Performance of Low-Friction Carbon Coatings Under Oil Lubrication

Friction and Wear Performance of Low-Friction Carbon Coatings Under Oil Lubrication

Near-frictionless carbon coatings for spark-ignited direct-injected fuel systems. Final report, January 2002.

Superlubricity and Wearless Sliding in Diamondlike Carbon Films

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