Oxidation resistance of (Ti,Al,Cr)N coatings at 800 ℃

The composite metastable(Ti0.5Al0.5)N,(Ti0.45Al0.45Cr0.1)N and(Ti0.35Al0.35Cr0.3)N coatings were respectively deposited on a wrought martensite steel 1Cr11Ni2W2MoV for aero-engine compressor blades by arc ion plating technique with pulse substrate bias. All the coatings have B1NaCl phase with a(200) preferred orientation and dense structures. The results show that the introduction of Cr into(Ti,Al)N gives rise to a minute shrinkage of crystal lattice. The incorporation of chromium into the coatings dramastically improves the oxidation-resistance of the coatings. For(Ti0.5Al0.5)N,a layered oxide scale forms after 100 h oxidation and the outer layer is the blend oxide of TiO2 and Al2O3,and the middle layer is rich in Al and the inner layer is rich in Ti. For(Ti0.45Al0.45Cr0.1)N,the oxide scale possesses a double-layered structure and the outer layer is rich in Ti. For(Ti0.35Al0.35Cr0.3)N,a Cr-rich compound oxide scale of Ti,Al and Cr forms,and a out-diffusion of Fe from steel to the nitride coating and oxide film during the oxidation takes place.

The composite metastable （Ti0.5Al0.5）N, （Ti0.45Al0.45Cr0.1）N and （Ti0.35Al0.35Cr0.3）N coatings were respectively deposited on a wrought martensite steel 1Crl 1 Ni2W2MoV for aero-engine compressor blades by arc ion plating technique with pulse substrate bias. All the coatings have B1NaCl phase with a （200） preferred orientation and dense structures. The results show that the introduction of Cr into （Ti,Al）N gives rise to a minute shrinkage of crystal lattice. The incorporation of chromium into the coatings dramastically improves the oxidation-resistance of the coatings. For （Ti0.5Al0.5）N, a layered oxide scale forms after 100 h oxidation and the outer layer is the blend oxide of TiO2 and Al2O3, and the middle layer is rich in AI and the inner layer is rich in Ti. For （Ti0.45Al0.45Cr0.1）N, the oxide scale possesses a double-layered structure and the outer layer is rich in Ti. For （Ti0.35Al0.35Cr0.3）N, a Cr-rich compound oxide scale of Ti, AI and Cr forms, and a out-diffusion of Fe from steel to the nitride coating and oxide film during the oxidation takes place.