Transparent tetragonal zirconia prepared by sinter forging at 950 °C

Transparent tetragonal ZrO2 (3-mol% yttria-stabilized zirconia [3YTZ]) was fabricated by sinter forging of nanoparticles at 950 °C with applied stress of 200 MPa. In this study, the initial compact prepared by gel-casting had a densely packed structure of nanoparticles, and the calcined compact exhibited slight translucency. The grain size of the resulting dense sample was approximately 47 nm. In-line transmittance for a 0.9-mm-thick sample was 28% at a wavelength of 640 nm, representing 37% of the theoretic value. Meanwhile, the sample with the best transparency in this study was slightly whitish. This study demonstrated that combining nanoparticle gel-casting with external pressure to lower the sintering temperature is an effective method for obtaining transparent tetragonal zirconia.