High-temperature water vapor corrosion behavior of Lu4Hf3O12 phase

High-temperature water vapor corrosion behavior of Lu4Hf3O12 was studied at 1500 °C in 30 wt.% H2O environment for 50 h. The rate of weight loss for this sample during the corrosion test was 1.347×10−6 g/cm2 h. On the surface of corrosion-tested specimen, a localized smooth surface was observed in some places and the grain boundary interface was covered by other phase that appears like string shape. The melted phase when measured by EDX method contained 37.2 mol% of Lu2O3 that was slightly lower than that of Lu2O3 content in Lu4Hf3O12 stoichiometric composition. And the Lu2O3 content of the string like melted phase was as higher as 53.7 mol% revealing a Lu-rich composition. The X-ray diffraction analysis of the after corrosion-tested sample showed very small peaks corresponding to melted phase.