Increasing the Sintering Rate and Strength of ZrO2–Al2O3 Ceramic Materials by Iron Oxide Additions

Abstract

We have prepared powders and ceramic composite materials in the ZrO2–Al2O3 system containing 10 and 20 wt % Al2O3 and examined the effect of ferric oxide additions on the linear shrinkage, phase composition, porosity, microstructure, and mechanical properties of the ZrO2–Al2O3 ceramic materials. The results demonstrate that the addition of ferric oxide leads to a considerable increase in linear shrinkage and ensures porosity as low as under 1% even at a sintering temperature of 1450°C in both composite materials. Moreover, small amounts of the additive stabilize the tetragonal phase of ZrO2, whereas increasing the Fe content to 3 mol % leads to an increase in the amount of the monoclinic phase. We have obtained densely sintered ZrO2–10% Al2O3 and ZrO2–20% Al2O3 ceramic materials at 1450°C, with a bending strength of up to 760 and 475 MPa, respectively.