Highly transparent Y 2 O 3 ceramics using TiO 2 as an additive were synthesized by presintering and hot isostatic pressing (HIP). The effects of TiO 2 contents and sintering conditions on the optical properties of the final transparent ceramics were investigated. A small amount (0.04-0.16 wt%) may decrease the densification temperature by about 200°C. The Y 2 O 3 ceramics doped with 0.16 wt% TiO 2 revealed a transparency of 82% in the wavelength range 1-6 μm. The thermal conductivity of the samples is about 11.8 W/m K at 25°C, which is close to that of the undoped Y 2 O 3 ceramics.
This paper aims to improve the density and thermal shock resistance of Y 2 O 3 ceramics for the preparation of ultra-pure high-temperature alloy crucible materials. The doping effect of MgF 2 content on the densification behavior, physical properties, and thermal shock resistance of Y 2 O 3 ceramics was systematically investigated in this paper. The results suggested that the presence of MgF 2 greatly promoted the growth of Y 2 O 3 grains and the transformation of the pore structure by liquid-phase sintering. And the mechanical properties of the MgF 2 -doped Y 2 O 3 ceramics were significantly improved. Besides, the marked improvement in the thermal shock resistance of MgF 2 -doped Y 2 O 3 ceramics was attributed to the synergistic action resulting from the growth of grain size and the enhancement of the crack deflection effect. In particular, the relative density of Y 2 O 3 ceramics doped with 1.5 wt% MgF 2 reached 96.4% and the residual flexural strength ratio after thermal shock achieved 45.0%, showing an excellent application prospect.
This paper presents the successful homogeneous processing of Y 2 O 3 green compacts by pressure-assisted alcoholic slip casting (PASC) method for the preparation of high-quality Y 2 O 3 transparent ceramics. The optimal Y 2 O 3 alcoholic slurry with 1.5 wt% polyethyleneimine as the dispersant and the solid load of 30.69 vol% was employed for PASC. Compared to dry-pressing green compact, PASC-prepared green compact exhibits high homogeneity and sinterability with less microstructural defects, such as large pores or particle agglomeration . Based on these advantages, we successfully prepared transparent Y 2 O 3 ceramic by simply vacuum sintering with low porosity, excellent optical homogeneity, and high in-line transmittance of 80.4% at the wavelength of 600 nm.