Influence of gadolinia on thermal expansion property of ZrO2-4.5 mol%Y2O3 ceramics

This paper concentrates on the influence of gadolinia on structure and thermal expansion property of ZrO2-4.5 mol%Y2O3 (YSZ) ceramics. The YSZ-xGd(2)O(3) (0 <= x <= 7.5 in mol%) ceramics were synthesized by solid state reaction method at 1500 degrees C for 2 h in air. The relative density, phase structure and thermal expansion property of YSZ-xGd(2)O(3) ceramics were investigated by the Archimedes method, X-ray diffraction and high-temperature dilatometer. The thermal expansion coefficients of YSZ-xGd(2)O(3) ceramics increase with the increase in temperature. The thermal expansion coefficients of YSZ-xGd(2)O(3) ceramics first decrease with increasing the mole fraction (x) of gadolinia from x = 0 (YSZ) to x = 4.5 (YSZ-xGd(2)O(3)) and then increase from x = 4.5 (YSZ-xGd(2)O(3)) to x = 7.5 (YSZ-xGd(2)O(3)) in the temperature range of 50-1200 degrees C. The YSZ-xGd(2)O(3) ceramics have the lowest thermal expansion coefficient in YSZ-xGd(2)O(3) ceramics, which is due to formation of the (Gd-Zr'V(O) over barYZr') ionic vacancy clustering. (C) 2008 Elsevier B.V. All rights reserved.