Role of annealing temperatures on the evolution of microstructure and properties of Cr2O3 films

Cr2O3 films were deposited on Ni-based high-temperature alloy substrates by using a cathodic arc ion plating system and then annealed in air at different temperatures. The effects of different annealing temperatures on the microstructure, mechanical and tribological properties of the films were examined. Results showed that the as-deposited Cr2O3 films were primarily amorphous with crystallization and vaporization temperatures of 360 °C and 940 °C, respectively. Annealing above the crystallization temperature improved the hardness, adhesion, and wear life of the Cr2O3 films. A mesh-like heave structure comprising Cr2O3 and Cr2Ti7O17 phases formed on the film surface after annealing above the vaporization temperature. The mesh-like heave structure endued the film with excellent tribological properties in a wide temperature range from room temperature (RT) to 1000 °C.