Generation mechanism of Si–Y–B-Yb ceramics with enhanced water-oxygen corrosion resistance

This study systematically investigates the influence of preparation temperature on microstructure and generation mechanism of Si–Y–B-Yb ceramics as anti-corrosion matrix. Main phases of Si–Y–B-Yb ceramics are Y/YbB 4 , YSi 2 , and Si, where Y/YbB 4 is derived from the reaction between YSi 2 and YbB 6 . With increase in preparation temperature, open porosity of Si–Y–B-Yb ceramics gradually decreases, reaching 0.24 % at 1350 °C, and internal phases transform from a dispersed distribution to clearly defined boundary state. Based on this, high-temperature water-oxygen corrosion behavior of Si–Y–B-Yb ceramics is characterized in 50 vol% H 2 O+50 vol% O 2 environment at 1250 °C for 100 h. In this corrosive environment, silicate phase appears on the surface of Si–Y–B-Yb ceramics. With prolonged corrosion time, silicate phase gradually forms more complete protective layer, hindering further corrosion by water-oxygen environment. These results demonstrate the feasibility of proposed Si–Y–B-Yb materials for corrosion protection.