Densification mechanism and thermal shock resistance improvement of MgF2-doped Y2O3 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.