Wear acceleration of a-C:H coatings by molybdenum-derived particles: Mixing and temperature effects. (July 2021)

• Record Type: Journal Article
• Authors: Kassim, K.A.M.; Tokoroyama, T.; Murashima, M.; Lee, W.-Y.; Umehara, N.; Mustafa, M.M.B.
• Is Part Of: Tribology international. Volume 159(2021)
• Publication Date: 2021-07
• Subjects: SERS -- MoDTC -- Hydrogenated amorphous carbon -- Wear acceleration; Tribology -- Periodicals; 621.89
• DOI: 10.1016/j.triboint.2021.106944
• Languages: English
• ISSNs: 0301-679X

Abstract

Abstract: MoDTC has also been reported to degrade into other Mo-derived compounds. It is essential to analyze the effects of each type of MoDTC-degraded material on DLC. Therefore, we chose powder-type MoDTC, MoS2, Mo, MoO3, and Mo2 C additives to be dispersed individually into a base oil and tested on an a-C:H sliding against a steel ball under boundary lubrication conditions at 80 °C. We then obtained surface-enhanced Raman scattering (SERS), which proved that MoS2 has the possibility of extracting hydrogen from the topmost surface as chemical wear (hydrogen content decreased from 30 to 35 at.% to 20 at.% of as-deposited) and that MoO3, MoDTC, and Mo have the possibility of catalytic reactions with carbon atoms. Mo2 C exhibited abrasive accelerate of the a-C:H wear. Highlights: MoDTC, MoS2, MoO3, Mo2 C, and, Mo to determine which Mo-derived compounds play significant roles in enhancing the wear of a-C:H was performed at 80°C. Only MoS2 showed a great reduction of the hydrogen content. The SERS analysis allowed us to obtain Raman data from less than 2 nm depth within the topmost surface.