Hot corrosion behavior of V2O5-coated Gd2Zr2O7 ceramic in air at 700-850 °C

Gd2Zr2O7 ceramic was prepared by solid state reaction at 1650 degrees C for 10 h in air, and exhibited a defect fluorite-type structure. Reaction between molten V2O5 and Gd2Zr2O7 ceramic was investigated at temperatures ranging from 700 to 850 degrees C using an X-ray diffractometer (XRD) and scanning electron microscopy (SEM). Molten V2O5 reacted with Gd2Zr2O7 to form ZrV2O7 and GdVO4 at 700 degrees C; however, in a temperature range of 750-850 degrees C, molten V2O5 reacted with Gd2Zr2O7 to form GdVO4 and m-ZrO2. Two different reactions observed at 700 degrees C and 750-850 degrees C could be explained based on the thermal instability of ZrV2O7. (C) 2009 Elsevier Ltd. All rights reserved.