Microstructure and hot corrosion behavior of Co-Si modified aluminide coating on nickel based superalloys

Co-Si modified aluminide coating on nickel based superalloys was prepared by pack cementation process, then microstructure and hot corrosion resistance were studied. The mass gain of Co-Si modified aluminide coating is 0.32 mg/cm2 after hot corrosion at 1173 K for 100 h. Si can boost the hot corrosion resistance by improving the formation of Al2O3 . SiO2 has low solubility over a wide range of salt acidity and good stability in the melting Na2SO4 + NaCl, preventing rapid corrosion attack and prohibiting the high fluxing rate.