Microstructure evolution and hot corrosion behavior of Zr-Y modified silicide coating prepared by two-step process

摘要

Zr-Y modified silicide coating on the Nb-Si based ultrahigh temperature alloy is prepared by firstly magnetron sputtering Ti-5Al-10Nb-2Zr (at.%) alloy film and then Si-Y co-deposition. The coating is mainly composed of a TiSi2 outer layer, a relatively thick (Nb,X)Si-2 inner layer and a thin transitional layer. The mass gain of the bare alloy, simple Si-Y coating and two-step coating is 97, 7.3 and 4.1 mg/cm(2) respectively after hot corrosion at 900 degrees C for 100 h in Na2SO4+NaCl molten salts. The hot corrosion mechanism of the coating has been revealed.