Fabrication of Highly Transparent Y2O3 Ceramics via Colloidal Processing Using ZrO2-Coated Y2O3 Nanoparticles

Abstract

An easy approach is described for the preparation of ZrO2-coated Y2O3 nanopowder from a solution of zirconium nitrate with commercial Y2O3 nanopowder. The evolution process of the ZrO2 coating layer upon calcination, such as the phase and microstructure of the particles’ surface, was studied. Calcination of the powder at 700 °C resulted in ZrO2-coated Y2O3 nanopowder. The rheological properties of the suspensions of ZrO2-coated Y2O3 powders were studied. A well-dispersed suspension with a solid loading of 35.0 vol% using ZrO2-coated Y2O3 nanopowder was obtained. The consolidated green body obtained by the centrifugal casting method showed improved homogeneity with a relative density of 50.2%. Transparent ceramic with high transparency and an average grain size of 1.7 µm was obtained by presintering at 1500 °C for 16 h in air, followed by post-HIP at 1550 °C for 2 h under 200 MPa pressure. The in-line transmittance at the wavelength of 1100 nm (1.0 mm thick) reached 81.4%, close to the theoretical transmittance of Y2O3 crystal.