The Effect of Lubricant Chemistry on Wear and Scuffing of Coated Surfaces

This study focuses on the effect of lubricant chemistry on wear and scuffing of coated surfaces. The coated surfaces in the present work include TiAlN, TiN, and CrN in the presence of different lubricants including high-oleic sunflower oil, high-oleic corn oil, fully-formulated sunflower oil, fully-formulated corn oil, and a synthetic base oil. The tests are conducted using the four-ball wear test to study the wear and scuffing properties. The scanning electron microscope (SEM) and optical microscope with MicroXAMR are used to study the wear mechanism. The study shows that coatings do not affect the friction coefficient at severe test conditions. However, some coatings, TiN and CrN, improve the wear properties even in base fluids without additives. All coatings improve the scuffing properties and increase the contact severity index. The vegetable-based lubricants perform comparably to commercially available synthetic lubricants.