Tribological studies of soft and hard alternated composite coatings with different layer thicknesses

In order to study the potential tribology using of composite coatings in which soft and hard layers are alternated, three common self-lubricating and anti-wear materials are deposited on bearing material matrix. Coatings with three different thicknesses are engineered to contain alternated layers of MoS2, WC and Cu. They are tested by different contact loads and sliding velocities. The damage and failure of composite coatings are analyzed by finite element analysis. Results show that loads and velocities have significant effects on coating frictional properties. The soft layer decrease frictional coefficients, and the hard layer bear heavy loads. Frictional coefficients can be adjusted by loads, velocities and coating thicknesses. The matrix is protected effectively by alternated coatings. •The mechanisms, functions and tribological properties of composites coatings are illustrated.•Equivalent stress, crack generation and thermal rise are shown.•CoFs can be adjusted by contact loads, sliding velocities and coating thicknesses.