Corrosion and recession mechanism of Lu2Si2O7/mullite eutectic

A Lu2Si2O7/Al6Si2O13 (mullite) eutectic oxide was discovered by the authors in the Lu2O3–SiO2–Al2O3 ternary system. The composition of the eutectic was Lu2O3:SiO2:Al2O3 = 18.1:54.6:27.3 in molar ratio. The eutectic point was at approximately 1500–1550 °C. Since this eutectic system has no boundary phase even if this system contains silicate component, no selective corrosion of the mullite phase occurred during static state water vapor corrosion test at 1300 °C. However, a selective recession of mullite phase was observed under a high velocity steam jet environment at 1200 °C.