The effects of the temperature and pressure on ZrO2-doped transparent yttria ceramics fabricated by a hot-pressing method

Previously, we briefly reported the fabrication of highly transparent yttria ceramics with fine microstructures by a facile hot-pressing method. In this article, we systematically studied the hot-pressing sintering of transparent yttria ceramics in which the effects of the ZrO2 doping concentration, sintering temperature, and mechanical pressure on the transparency as well as the microstructures of the ceramic samples were investigated in detail. It was found that the optimal ZrO2 doping concentration for the hot-pressed transparent yttria ceramics is 1 at.%, which is much lower than that of transparent yttria ceramics fabricated by pressureless sintering routes. An increase in both the hot-pressing temperature and the mechanical pressure effectively promoted the densification and the optical transparency of the samples doped with 3 at.% ZrO2. However, when the mechanical pressure is too high, a substantial reduction of yttria occurs, which deteriorates the transparency of the samples.