Mechanical and thermal properties of porous yttria-stabilized zirconia

Abstract

ABSTRACTThis paper reports on analyses of the compressive Young’s modulus (Ep), compressive strength (σp) and thermal conductivity (κ) of sintered porous yttria-stabilized zirconia compacts (YSZ). The Ep and σp values are affected by the number of grains and the grain boundary area in sintered YSZ ceramics. The measured porosity dependence of the Ep and σp values was compared with that of the theoretical Ep and σp values derived for the open pore structure. The tendency of Ep and σp values to increase at low porosity was clarified by the proposed theoretical porosity dependence of Ep and σp. The strain at fractures also increased with increases in the grain boundary area and depended on the crack propagation mode affected by the degree of grain growth. The κ values for porous YSZ, which decreased at high porosity, were analyzed theoretically with two model structures: a pore-dispersed YSZ continuous phase system (F model) and a YSZ-dispersed pore continuous phase system (G model). The measured κ values at 0–30% porosity were in good agreement with the κ values calculated for the model F structure. In the high porosity range above 50%, the measured κ values approached the κ value curve for the model G structure with increases in porosity.