Tribochemistry and Wear Life Improvement in Liquid-Lubricated H-DLC-Coated Bearings
Abstract
In contrast to typical DLC coatings, hydrogenated DLC (H-DLC) coatings exhibit extremely low friction in vacuum and dry atmospheres, suggesting their potential importance for spacecraft applications. We have conducted a study of H-DLC coated steel thrust bearings, lubricated with a multiply-alkylated cyclopentane oil, either unformulated, or formulated wit lead naphthenate or an aryl phosphate ester mixture. Data on uncoated steel thrust bearings were obtained for comparison. The surface chemistry of the additives on worn H-DLC surfaces was evaluated along with chemical analysis of the residual lubricant. In contrast with results on uncoated steel bearings, minimal additive-based tribofilm formation was detected on the surfaces of the H-DLC coatings in the wear tracks. The results indicate that additives optimized for steels may no be appropriate for H-DLC coatings. Although there were indications that H-DLC coatings increase endurance, the high roughness of the bearings contributed to statistical uncertainty. Future studies are planned with higher quality bearings.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 25, 2007
- Accession Number
- ADA471592
Entities
People
- A. Erdemir
- H. I. Kim
- J. R. Lince
- O. L. Eryilmaz
- P. A. Bertrand
Organizations
- The Aerospace Corporation