Superior Oxidation Resistance of (Al0.34Cr0.22Nb0.11Si0.11Ti0.22)50N50High-Entropy Nitride

The oxidation resistance of (Al0.34Cr0.22Nb0.11Si0.11Ti0.22)50N50 high-entropy nitride coating prepared by reactive magnetron sputtering was studied. The oxide layer on the coating surface was 290 nm after 50 h annealing at 900°C. The weight gain after thermal ramping to 1300°C was merely 0.015 mg cm−2. Such oxidation resistance is superior to reported nitride coatings. Eight layers of oxides with different compositions were observed in the scale by TEM. The superior oxidation resistance is owing to the protection of the dense Al2O3 layer and inner Si-rich amorphous network.