CONTROL OF GRAIN-GROWTH USING INTERGRANULAR SILICATE PHASES IN CUBIC YTTRIA-STABILIZED ZIRCONIA

Grain growth kinetics for 8 mol% yttria stabilized cubic zirconia (8Y- CSZ) were investigated. Optimal process parameters required to achieve a small grain size and full density for cubic 8Y-CSZ included a rapid heating rate (100 degrees C/min) and hot isostatic pressing. Grain gr owth rates could also be controlled by the deliberate addition of 1 wt % of intergranular phases of borosilicate, barium silicate, and lithiu m aluminum silicate glasses. Lithium aluminum silicate, the intergranu lar phase with the highest solubility for yttria and zirconia, enhance d grain growth compared to control samples without grain boundary phas es. The borosilicate intergranular phase, with the lowest solubility f or yttria and zirconia, was the most effective in suppressing grain gr owth. Activation energies for grain growth were in the range of 400 kJ /mol, and the grain growth exponent ranged from 2 for Lithium aluminum silicate containing samples, to 3 for pure samples, to 4 for barium s ilicate and borosilicate containing samples. (C) 1998 Acta Metallurgic a Inc.