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

摘要

Gadolinium zirconate (Gd_2Zr_2O_7) prepared by solid state reaction exhibited a defect fluorite-type structure. Reactions between Gd_2Zr_2O_7 ceramic and vanadium pentoxide (V_2O_5), sodium sulfate (Na_2SO_4), and V_2O_5 + Na_2SO_4 mixture were investigated from 700 to 1000 ℃ in air using an X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). V_2O_5 reacts with Gd_2Zr_2O_7 to form gadolinium vanadate (GdVO_4) and monoclinic zirconia (m-ZrO_2) at 900 and 1000 ℃ in air. However, no chemical reaction product between Na_2SO_4 and Gd_2Zr_2O_7 is found at 900 and 1000℃ in air. V_2O_5 reacts with equal molar Na_2SO_4 to form sodium vanadate (NaVO_3 ) at 610℃. In the temperature range of 700-1000℃, Na_2SO_4 + V_2O_5 mixture reacts with Gd_2Zr_2O_7 in air to form the final reaction products of GdVO_4 and m-ZrO_2.