Effect of humidity and oxygen on friction, wear and durability of a polymer-bonded molybdenum disulfide (MoS2)-based dry film lubricant (DFL) coating system in large amplitude fretting

Laolu-Balogun, E.; Owen, S.; Read, S.; Shipway, P.H.; Voisey, K.T.

Abstract

Investigations into effects of humidity and oxygen on a polymer-bonded MoS2-based dry film lubricant (DFL) coating, on grit-blasted Ti-6Al-4V using a cylinder-on-flat configuration, are reported. Sustained low friction and low wear occurred in both low-humidity air and low-humidity argon, producing significant extension of fretting wear lifetimes. A cracked-paved structure was observed in low-humidity air which was not observed in low-humidity argon. The Mo-DFL coatings were observed to be highly sensitive to humidity. As humidity increased, a notable rise of friction and wear ensued which reduced the system lifetime. Different friction evolution was observed in high-humidity air and high-humidity argon before failure, with a short-lived but established low friction phase in high-humidity air and a consistent high friction phase in high-humidity argon. Although oxidation of the MoS2 to MoO3 is a key process of degradation of DFLs of this type, this oxidation reaction does not operate in the absence of humidity.

Citation

Laolu-Balogun, E., Owen, S., Read, S., Shipway, P., & Voisey, K. (2024). Effect of humidity and oxygen on friction, wear and durability of a polymer-bonded molybdenum disulfide (MoS2)-based dry film lubricant (DFL) coating system in large amplitude fretting. Wear, 552-553, Article 205426. https://doi.org/10.1016/j.wear.2024.205426

• Journal Article Type: Article
• Acceptance Date: May 26, 2024
• Online Publication Date: May 30, 2024
• Publication Date: Aug 15, 2024
• Deposit Date: Jun 6, 2024
• Publicly Available Date: Jun 12, 2024
• Journal: Wear
• Print ISSN: 0043-1648
• Electronic ISSN: 1873-2577
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 552-553
• Article Number: 205426
• DOI: https://doi.org/10.1016/j.wear.2024.205426
• Keywords: Dry film lubricant; Fretting; Humidity; Oxygen; Molybdenum disulphide; Environment
• Public URL: https://nottingham-repository.worktribe.com/output/35712765
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0043164824001911?via%3Dihub