Spark plasma sintering of zirconia-doped yttria ceramic and evaluation of the microstructure and optical properties

In the present study, 3.0 at% ZrO₂-Y₂O₃ nanopowder was prepared by ball milling for 20 h, and the particle size was reduced significantly down to 78±3.8 nm. Transparent pure yttria and zirconia-doped yttria ceramics were fabricated through spark plasma sintering (SPS) with a heating rate of 100 °C/min at 1500 °C for 20 min, under a pressure of 100 MPa. The average grain size of zirconia-added yttria ceramic decreased from 0.83±0.29 µm to 0.23±0.09 µm, whereas its lattice parameter slightly decreased. With addition of zirconia the transparency of yttria ceramics increased markedly in the visible region. The highest transmittance of the 3.0 at% zirconia–doped yttria ceramic reached 83.18% at the wavelength of 5 µm for 2.5 mm thick, which is very close to the theoretical value of yttria.