Microstructure and thermal stability of Ti1-xAlxN coatings deposited by reactive magnetron co-sputtering

Ti1-xAlxN (0.25≤x≤0.75) coatings were deposited by reactive DC/RF magnetron co-sputtering. The phase structure, microstructure, surface roughness and chemical composition were investigated. The anti-oxidation behavior of coatings at high temperature was also studied. It has been shown that the coatings with high Al content (x≥0.67) consisted of hexagonal-AlN and cubic-TiAlN phases, while it has cubic-TiAlN phase for the coatings with low Al content (x < 0.67). The roughness of surface of coatings was 1.89∼ 4.80 nm and it decreased with increasing the Al content. The thermal-stability of the Ti1-xAlxN coatings increased with increasing Al content.