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

Publication date: 5 October 2018
Source:Materials & Design, Volume 155
Author(s): Zhenyang Cai, Yonghuang Wu, Huyun Liu, Gengyu Tian, Rong Pu, Shengming Piao, Xinyang Tang, Sainan Liu, Xiaojun Zhao, Lairong Xiao
A new YSZ (yttria stabilized zirconia) modified silicide coating was prepared on Mo-based alloy through a two-step 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, the mass gain was 0.96 mg/cm² after being exposed at 1725 °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.

Graphical abstract

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