Effect of Microstructure and Composition of Molybdenum and Tungsten-Doped Vacuum Ion-Plasma Carbon Coatings on Their Tribotechnical Properties under Dry Friction and Boundary Lubrication

The paper presents the results of a study of the chemical and phase composition, structure, physical-mechanical and tribological characteristics of two types of vacuum ion-plasma antifriction carbon coatings alloyed with molybdenum and tungsten, respectively. The first of these types of coatings has a highly oriented linear-chain structure; the second type is an amorphous hydrogenated carbon. The tribotechnical characteristics of the studied coatings were evaluated on a four-ball machine with a modernized friction unit and were carried out both under dry friction and under friction in the boundary lubrication mode in inactive (polyalphaolefin oil PAO-4), surface-active (PAO-4 + 1 % by weight of oleic acid) and chemically active (the same oil + 2 % by weight of DF-11 additive) lubricating environments. It was found that the coating with both “monocrystal” carbon and diamond-like carbon, both alloyed and unalloyed, significantly reduced friction losses and wear of the steel samples to which the coatings were applied, and alloying of these coatings reduced friction almost as much as the studied lubricants. Thus, under dry friction of a ball made of ShKh-15 steel on the cylindrical surfaces of rollers made of the same steel, the friction coefficient obtained was ~ 0.8; when a ball rubs against rollers coated with a molybdenum-doped “monocrystalline carbon” coating, the dry friction coefficient is ~ 0.7; additionally, in an inactive oil environment, this friction pair provides a friction coefficient of 0.12—0.14; and in a chemically active sulfur-containing oil environment, the friction coefficient decreases to 0.05. For a friction pair of steel — molybdenum-doped diamond-like coating, with boundary lubrication by a surface-active composition, the minimum friction coefficient is 0.09. Taking into account the obtained results of the proposed study will allow optimizing the process of creating highly effective lubricants for heavily loaded friction units.

1. Bewilogua K. and Hoffman D. History of Diamond-Like Carbon Films – from Experiments to Wordwise Application // Surf. Coating Technol. — 2014 (242), 214—235. doi: 10.1016/j.surfcoat.2014.01.031

2. Tyagi A., Walia R.S., Oasim M., Pandey S.M., Tyagi M.K., and Bharat B. A critical Review of Diamond-Like Carbon Coatings for Wear Resistance Applications // Int. J. Refract. Met. Hard Mater. — 2019 (78), 107—122

3. Modern Technologyes for modifying the surface of machine parts / Ed by G.K. Moskvitin. — Moscow: URSS/LENAND. — 2013 (in Russian)

4. Goryacheva I.G., Torskaya E.V., Kornev Yu.V., Kovaleva I.N., and Myshkin N. K. Theoretical and Experimental Study of the Mechanical Properties of Bicomponent Metal Vapor Deposited Coatings// Journal of Friction and Wear. — 2015 (36), no. 3, 262—265. DOI: 10.3103/S1068366615030058

5. Semenov A.P. and Khrushchov M.M. Influence of the External Media and Temperature on the Tribological Properties of Diamond and Diamond-Like Coatings // Friction and Wear. — 2010 (31), no. 2, 195—217 (in Russian).

6. Kalin M., Velkarvrh I., and Vizintin J. Role of Adsorption and Tribophysical Parameters in Lubrication of DLC // Proceedings on the Tribology Congress IV (WTC 2009). — Kyoto. — 2009, 25.

7. Streletskiy O.A., Ivanenko I.P., Khvostov V.V., Savchenko N.F., Nishak O.Yu., Alexandrov A.F. Structural features of carbon materials synthesized by various methods // Solid State Physics. — 2016 (58), 2044—2049 (in Russian)

8. Kalin M., Velkavrh I., Vizintin J., and Osbolt L. Review of Boundary Lubrication Mechanisms of DLC Coatings Used in Mechanical Application // Meccanica. — 2008 (43), no. 6, 623—637

9. Miyake S., Mitsuyoshi K., Kurosaka W., Matsumoto Y., Saito Y., Yasuda Y., and Okamoto Y. Boundary Lubrication Characteristic of Metal-Containing Diamond-Like Carbon (DLC) Films with Poly Alpha Olefin (PAO) Lubricant // Tribol. Online. — 2008 (3), no. 5, 310—315 10. Zapid R., Zapid R., Masjuki H.H., Varman H., Mufti K.A., Kasam M.A., and Guslar M. Effect of Lubricant Formulation on the Tribological Performance of Self-Mated Dropped DLC Contacts. A Review // Tribol. Letter. — 2015 (58), no. 2, 1—28

10. Buyanovskii I.A., Khrushchov M.M., and Samusenko V.D. Tribological Behavior of Diamond-Like Carbon Coatings under Boundary Friction. Part I. Structure, Testing methods. Lubrication by Adsorption Layers. Part II. Lubrication with Chemical Modified Layers // Inorganic Materials: Applied Research. — 2021 (13), no. 4, 893—913

11. Semenov A.P. Tribological Properties and Vacuum Ion-Plasma Methods of Application of Diamond and Diamond-Like Coatings // Journal of Friction and Wear. — 2009 (30), no. 1, 62—75

12. Antifriction coating: patent of the Russian Federation for an invention. RU 2528449 C1. 07.29.2020. / A.Yu. Albagachiev, I.A. Buyanovskiy, V.A. Levchenko, V.D. Samusenko (in Russian)

13. Topolyansky P.A., Topolyansky A.P., Ermakov S.A., Kanaev A.T., Biyzhanov S.K., Sarsembayeva T.E. Certification of materials and coatings by physical and mechanical characteristics of the surface layer // Bulletin of modern studies. — Omsk: NC “Orka”. — 2018, no. 10-1 (25), 354—366 (in Russian)

14. Avdyukhina V.M., Khrushchov M.M., Sulyandziga D.A., Levin I. S. X-ray Diffraction Studies of the Effect of Phase Composition and Structural State Characteristics on the Tribological Behavior of the Molybdenum- and Tungsten-Based Strengthening Coatings // Crystallography Reports. — 2023 (68), no. 3, 468—477