Influence of terminal pH value on co-precipitated nanopowders for yttria-stabilized ZrO2 transparent ceramics

Abstract Y0.16Zr0.84O1.92 nanopowders were co-precipitated from the mixed solution of zirconium oxychloride and yttrium nitrate using ammonia as the precipitant. The influences of terminal pH value on the chemical composition and morphology of the Y0.16Zr0.84O1.92 precursors and powders were characterized. The precursors with terminal pH = 8.5–9.25 completely transform to cubic ZrO2 phase when calcined at 800 °C. The Y0.16Zr0.84O1.92 powder with terminal pH = 9.0 shows the best dispersity, which is beneficial to the fabrication of transparent ceramics. Using the synthesized nanopowders as starting materials, Y0.16Zr0.84O1.92 ceramics were prepared by pre-sintering at 1350 °C for 2 h in air and HIP post-treatment at 1800 °C for 3 h under 200 MPa Ar without sintering additives. The Y0.16Zr0.84O1.92 ceramic sample fabricated from the powder with terminal pH = 9.0 shows the best optical quality, and its in-line transmittance exceeds 56.4% in the region of 400–850 nm, reaching 67.8% at 800 nm.