Microstructure, mechanical properties and tribological behaviors of TiAlN-Ag composite coatings by pulsed magnetron sputtering method

TiAlN-Ag composite coating was prepared by pulsed magnetron sputtering method on cemented carbide surface. The effect of silver content on the microstructure, mechanical properties and tribological behaviors of TiAlN-Ag composite coatings was studied. Results show that doping an appropriate amount of Ag into TiAlN coating can significantly refine the grain size of TiN nanocrystalline, reduce the internal stress, and improve hardness, plasticity and toughness, as well as the coating/substrate bond strength and tribological properties of the coating. Under dry friction conditions, the wear forms of TiAlN-Ag coating transfers from severe adhesion wear and brittle spalling of TiAlN coating to slight adhesion wear and abrasive wear, whereas the wear mechanism under oil lubrication changes from the comprehensive form of brittle fracture, fatigue peeling and abrasion to the mainly abrasive wear with slight fatigue spalling. Overall, the TiAlN-Ag composite coating with 2.40 at.% Ag exhibits the best comprehensive mechanical properties and wear resistance.