Highly Infrared Transparent Nanometric Tetragonal Zirconia Prepared by High‐Pressure Spark Plasma Sintering

Highly infrared transparent tetragonal ZrO 2 (3 mol% yttria‐stabilized) was prepared by means of high‐pressure spark plasma sintering ( HP‐SPS ). The crystallite size of the resulting dense sample was about 80 nm. In‐line transmittance for the 1.5 mm thick sample ranged between 63% and 67% in the wavelength of 3–5 μm, representing 81%–87% of the theoretic value. Meanwhile, the cutoff wavelength of tetragonal ZrO 2 was superior to the values of other high‐strength transparent ceramics. This study highlighted the efficiency and simplicity of HP‐SPS for obtaining transparent tetragonal ZrO 2 and the great potential of this ceramic applied for durable infrared windows.