Transparent yttria produced by spark plasma sintering at moderate temperature and pressure profiles

Transparent yttria (Y2O3) bodies were fabricated by spark plasma sintering, and the effects of the sintering temperature on relative density, microstructure, and the optical and mechanical properties of Y2O3 bodies were investigated. Fully dense Y2O3 bodies were obtained at sintering temperatures 1473–1873 K. The average grain size was 0.24–0.32 μm at 1473–1573 K, and steadily increased to 1.97 μm with an increase in temperature to 1823 K. The highest transmittance was obtained in the Y2O3 body sintered at 1573 K and annealed at 1323 K, showing 81.7% (99% of the theoretical value) at a wavelength of 2000 nm.