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

Abstract: This paper concentrates on the influence of gadolinia on structure and thermal expansion property of ZrO2–4.5mol%Y2O3 (YSZ) ceramics. The YSZ–xGd2O3 (0≤ x ≤7.5 in mol%) ceramics were synthesized by solid state reaction method at 1500°C for 2h in air. The relative density, phase structure and thermal expansion property of YSZ–xGd2O3 ceramics were investigated by the Archimedes method, X-ray diffraction and high-temperature dilatometer. The thermal expansion coefficients of YSZ–xGd2O3 ceramics increase with the increase in temperature. The thermal expansion coefficients of YSZ–xGd2O3 ceramics first decrease with increasing the mole fraction (x) of gadolinia from x =0 (YSZ) to x =4.5 (YSZ–4.5Gd2O3), and then increase from x =4.5 (YSZ–4.5Gd2O3) to x =7.5 (YSZ–7.5Gd2O3) in the temperature range of 50–1200°C. The YSZ–4.5Gd2O3 ceramics have the lowest thermal expansion coefficient in YSZ–xGd2O3 ceramics, which is due to formation of the () ionic vacancy clustering. [Copyright &y& Elsevier]