Effect of La2O3 on resistance to high-temperature oxidation and corrosion of aluminized and aluminum-chrome coating

In this paper, the effect of La2O3 on resistance to high-temperature oxidation and corrosion of aluminized and aluminum-chrome coating on the nickel-based superalloy GH625 was investigated. The results show that the addition of La2O3 can dramatically reduce the oxidation weight gain of coating, promote the formation of a protective oxide film and improve the adhesion of oxide film, which can enhance high-temperature oxidation resistance of the coating. In addition, La2O3 can also obviously improve the high-temperature corrosion resistance of the coating. After 100 h of the high-temperature corrosion, the corrosion weight gain of Al + La2O3 coating and Al-Cr + La2O3 coating was 6.01 mg cm(-2) and 4.49 mg cm(-2), respectively, with a decrease of 50% and 33% compared with La2O3 free coatings. The addition of La2O3 can refine the grain size, reduce the alkaline dissolution of Al2O3, and inhibit the diffusion of corrosive elements, which can increase the high-temperature corrosion resistance of the coating.