A novel Zr-Y modified silicide coating on Nb-Si based alloys as protection against oxidation and hot corrosion

y To protect Nb-Si based alloys from oxidation and hot corrosion attacks at high temperatures, a novel Zr-Y modified silicide coating is fabricated by combining magnetron sputtering and pack cementation. It has been shown that the coating exerts a superior oxidation resistance (mass gain of 1.6 mg/cm(2)) than Si-Y coating (mass gain of 4.2 mg/cm(2)), which is attributed to forming a thin, compact and continuous SiO2 scale and favorable scale/coating interface. Due to possessing much better scale adherence and reduced formation rate of scale, the coating possesses a better hot corrosion resistance than substrate alloy and Si-Y coating.