High-temperature hot corrosion behavior of gadolinium zirconate by vanadium pentoxide and sodium sulfate in air

Gadolinium zirconate (Gd2Zr2O7) prepared by solid state reaction exhibited a defect fluorite-type structure. Reactions between Gd2Zr2O7 ceramic and vanadium pentoxide (V2O5), sodium sulfate (Na2SO4), and V2O5 + Na2SO4 mixture were investigated from 700 to 1000 degrees C in air using an X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). V2O5 reacts with Gd2Zr2O7 to form gadolinium vanadate (GdVO4) and monoclinic zirconia (m-ZrO2) at 900 and 1000 degrees C in air. However, no chemical reaction product between Na2SO4 and Gd2Zr2O7 is found at 900 and 1000 degrees C in air. V2O5 reacts with equal molar Na2SO4 to form sodium vanadate (NaVO3) at 610 degrees C. In the temperature range of 700-1000 degrees C, Na2SO4 + V2O5 mixture reacts with Gd2Zr2O7 in air to form the final reaction products of GdVO4 and m-ZrO2. (C) 2010 Elsevier Ltd. All rights reserved.