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

Y 0.16 Zr 0.84 O 1.92 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 Y 0.16 Zr 0.84 O 1.92 precursors and powders were characterized. The precursors with terminal pH = 8.5–9.25 completely transform to cubic ZrO 2 phase when calcined at 800 °C. The Y 0.16 Zr 0.84 O 1.92 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, Y 0.16 Zr 0.84 O 1.92 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 Y 0.16 Zr 0.84 O 1.92 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.