Effects of annealing temperature on the microstructure, mechanical and tribological properties of CrAlTiN coatings

The microstructure, mechanical properties and tribological properties of CrAlTiN coatings with various atmospheric annealing temperature are systematically investigated. The results show that the hardness of the coating decrease with the annealing temperature increasing from room temperature to 800 °C, however, the elastic strain resistance H/E value increase firstly and then decrease. The deposited CrAlTiN coating is face-centered cubic structure, (111) and (200) planes show competition growth, while high annealing temperature promotes the growth of (200) planes. The main wear mechanisms of CrAlTiN coating against Si3N4 ball are adhesive and oxidative. The coatings annealed at 400 °C has the lowest wear rate and annealed at 800 °C peeled off during the friction process. The chromium oxide, aluminium oxide and titanium oxide with lubricating and high hardness adhered on the wear tracks, playing the role of supporting the counterballs, a low COF of the coating is obtained. The coatings annealed above 600 °C are more easily to form extensive smooth and dense oxide adhesives, but it takes longer to reach stable wear stage. Thus, the preferred annealing temperature could effectively regulate the microstructure and improve the mechanical and tribological properties of CrAlTiN coating.