Abstract: The paper presents results of the structure analysis and tribological testing of a-C:H type diamond-like carbon (DLC) coatings produced by the Plasma Assisted Chemical Vapour Deposition (PACVD) technology on 100Cr6 specimens. PACVD methods allow both deposition of thin films on the materials that can conduct an electrical current, and for non-conductive materials, electricity, using a radio frequency discharge currents and low. Essentially, the PACVD process aimed at the production of the hard surface layer or layers having specific properties: e.g. the protective, anticorrosive, tribological. This article discusses the properties of DLC coatings. The surface and cross-sectional microstructure and the chemical composition were assessed by means of a scanning electron microscope (SEM). The structure was studied using a JSM 7100F microscope with an EDS detector manufactured by JEOL. The coatings were analyzed by means of a Talysurf CCI-Lite non-contact 3D profiler. The wear resistance was established under dry friction conditions and in the presence of boundary lubrication conditions with polyalphaolefin PAO-8 oil and was studied by a ball-on-disc T-01M tribometer with the ball being made of 100Cr6 steel and the disc being made of the of 100Cr6 steel coated with DLC. The tribological tests conducted under technically dry friction and lubrication conditions showed that the diamond-like carbon coating had better properties than substrate material. The application of lubricants caused a decrease in the wear of the elements in friction pair. The use of lubricants in combination with a DLC coating has shown that this type of association of the grater greatly affects the smaller friction resistance.
B I B L I O G R A F I A[1] Neville A., Morina A., Haque T., Voong M.: Compatibility between tribological surfaces and lubricant additives. How friction and wear reduction can be controlled by surface/lube synergies. Tribology International 40 (2007) 1680÷1695.
[2] Madej M., Ozimina D., Kasińska J., Hawlena J.: The structure and characteristics of tribological systems with diamond like carbon coatings under ionic liquid lubrication conditions. Archives of Metallurgy and Materials 61/2B (2016) 273÷278.
[3] Kalin M., Vizintin J.: The tribological performance of DLC-coated gears lubricated with biodegradable oil in various pinion/gear material combinations. Wear 259 (2005) 1270÷1280.
[4] Fujii M., Kumar M. A., Yoshida A.: Influence of DLC coating thickness on tribological characteristics under sliding rolling contact condition. Tribology International 44 (2011) 1289÷1295.
[5] Yakabe F., Jinbo Y., Kumagai M., Horiuchi T., Kuwahara H., Ochiai S.: Excellent durability of DLC film on carburized steel (JIS-SCr420) under a stress of 3.0 GPa. Journal Physics Conference Serie 100 (2008) 082049.
[6] Milewski K., Kudliński J., Madej M., Ozimina D.: The interaction between diamond like carbon (DLC) coatings and ionic liquids under boundary lubrication conditions. Metalurgija 56 (2017) 255÷258.
[7] Mahmud K., Kalam M., Masjuki H., Mobarak H., Zulkifili N.: An unpdated overview of diamond-like carbon coating in tribology. Critical Reviews in Solid State and Materials Sciences 40 (2015) 90÷118.
[8] Aisenberg S., Chabot R.: Ion-beam deposition of thin films of diamond like carbon. Journal of Applied Physics 42 (1971) 2953÷2958.
[9] Zhiqiang F., Jian S., Chengbiao W., Wei Z., Wen Y., Zhijian P., Xiang Y., Songsheng L., Mingjiang D.: Tribological performance of DLC coatings deposited by ion beam deposition under dry friction and oil lubricated conditions. Vacuum 94 (2013) 14÷18.
[10] Madej M.: The effect of TiN and CrN interlayers on the tribological behavior of DLC coatings. Wear 317 (1-2) (2014) 179÷187.
[11] Ohana T., Suzuki M., Nakamura T., Tanaka A., Koga Y.: Tribological properties of DLC films deposited on steel substrate with various surface roughness. Diamond & Related Materials 13 (2004) 2211÷2215.
[12] Adamczak S.: Measurements of the surface geometry. WNT, Warszawa (2009).
[13] Tamura Y., Zhao H., Wang C., Morina A., Neville A.: Interaction of DLC and B4C coatings with fully formulated oils in boundary lubrication conditions. Tribology International 93 (2016) 666÷680.
[14] Podgornik B., Jacobson S., Hogmark S.: Influence of EP additive concentration on the tribological behaviour of DLC-coated steel surfaces. Surface and Coatings Technology – Journal Elsevier 191 (2005) 357÷366.
[15] Podgornik B., Hren D., Vizintin J., Jacobson S., Stavlid N., Hogmark S.: Combination of DLC coatings and EP additives for improved tribological behavioiur of boundary lubricated surfaces. Wear 261 (2006) 32÷40.
[16] Gangopadhyay A., Zdrodowski R. J., Simko S. J.: Interactions of diamond- like carbon coatings with fully formulated engine oils. Tribology Transactions 57 (2014) 503÷514.
[17] de Barros’Bouchet M. I., Martin J. M., Le-Mogne T., Vacher B.: Boundary lubrication mechanisms of carbon coatings by Mo DTC and ZDDP additives. Tribology International 38 (2005) 257÷264.
[18] Topolovec-Miklozic K., Lockwood F., Spikes H.: Behaviour of boundary lubricating additives on DLC coatings. Wear 265 (2008) 1893÷1901.
[19] Kosarieh S., Morina A., Laine E., Flemming J., Neville A.: Tribological performance and tribochemical processes in a DLC/steel system when lubricated in a fully formulated oil and base oil. Surface and Coatings Technology – Journal Elsevier 217 (2013) 1÷12.
[20] Erdemir A.: Review of engineered tribological interfaces for improved boundary lubrication. Tribology International 38 (2005) 249÷256.
[21] Dvorak S. D., Wahl K. J., Singer I. L.: Friction behavior of boric acid and annealed boron carbide coatings studied by in situ Raman tribometry. Tribology Transactions 45 (2002) 354÷362.
[22] Haque T., Morina A., Neville A.: Effect of friction modifiers and antiwear additives on the tribological performance of a hydrogenated DLC coating. Journal of Tribology 132 (2010) 1÷13.
[23] Schwan S. U. J., Batori V., Ehrhardt H., Silva S. R. P.: Raman spectroscopy on amorphous carbon films. Journal of Applied Physics 80 (1996) 440÷447. 
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