Effect of Y2O3 content in the pack on microstructure and hot corrosion resistance of Y-Co-modified aluminide coating

Y-Co-modified aluminide coatings on nickel base superalloys were prepared by pack cementation method. Effect of Y2O3 content in the pack mixture on microstructure and hot corrosion resistance of the coatings was investigated. The results show that with the increase in Y2O3 content, the content of Co in the coatings increases. The mass gain of the coatings with Y2O3 addition of 1, 2 and 3 wt.% is 0.6, 0.55 and 0.42 mg/cm(2) after hot corrosion at 1173 K for 100 h, respectively. Y2O3 addition accelerates the diffusion of Co and thus increases the hot corrosion resistance of the coating. (C) 2014 Elsevier Ltd. All rights reserved.