Friction and Wear Mechanisms of Cu/ta-C Coatings Under PAO-4 and PAO-4 with MoDTC Lubrication

Decelyne Elly Binjua; Seock-Sam Kim; Young-Jun Jang; Jong-Kuk  Kim

doi:10.38032/jea.2020.04.009

Authors

Decelyne Elly Binjua Department of Mechanical Engineering, Universiti Malaysia Sabah, Malaysia
Seock-Sam Kim Department of Mechanical Engineering, Universiti Malaysia Sabah, Malaysia
Young-Jun Jang Department of Extreme Environmental Coatings, Korea Institute of Materials Science, South Korea
Jong-Kuk Kim Department of Extreme Environmental Coatings, Korea Institute of Materials Science, South Korea

DOI:

https://doi.org/10.38032/jea.2020.04.009

Keywords:

Friction, Wear, Cu/ta--C Coating, PAO-4, MoDTC, FCVA

Abstract

The tribological behavior of various types of DLC coatings in formulated and non-formulated lubricants are needed for proper usage of these coatings. In this research, the friction and wear mechanism of four different DLC coatings in poly-alpha-olefin type 4 (PAO-4) with and without MoDTC were investigated using ball-on-disc tribometer. One ta-C (tetrahedral amorphous carbon) and three Cu/ta-C (copper doped ta-C) with different sputter power of 50 W, 150 W, and 200 W coatings were deposited on silicon wafers by using FCVA (filtered cathodic vacuum arc) technique for this research. The results indicate that ta-C coating on silicon wafer has the lowest average friction coefficient (CoF) and better wear resistance than Cu/ta-C coating when lubricated under PAO-4 oil with MoDTC. Cu/ta-C with sputter powers of 150 W and 200 W exhibited the highest average friction coefficient under PAO-4 oil with MoDTC. Meanwhile, the average CoF for all samples were similar under PAO-4 base oil. In terms of wear, ta-C coating showed the highest wear rate under PAO-4 base oil then followed by Cu/ta-C with sputter power of 50 W. Nonetheless, Cu/ta-C with sputter powers of 150 W and 200 W exhibited significantly low wear rate under PAO-4 base oil compared to PAO-4 oil with MoDTC.

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