Formation and oxidation resistance of a new YSZ modified silicide coating on Mo-based alloy

A new YSZ (yttria stabilized zirconia) modified silicide coating was prepared on Mo-based alloy through a twostep process, including spraying of Si-Mo-YSZ slurry followed by reaction sintering. Microstructure and oxidation behavior of the coatings with different YSZ content (0, 5, 10 and 15%) were studied. The coating consists of a MoSi2-ZrSi2-SiO2 outer layer and a MoSi2 inner layer. The 10% YSZ modified coating possessed the best oxidation protection at ultra-high temperatures and, for the coating, themass gainwas 0.96 mg/cm(2) after being exposed at 1725 degrees C in air for 22 h, whereas the uncoated Mo-based alloy completely ablated for 0.35 h. The excellent oxidation resistance of the silicide coating was attributed to the compact and self-healing SiO2 protective scale, which contained the dispersed ZrO2 and ZrSiO4. (C) 2018 Elsevier Ltd. All rights reserved.