Improved stability of BaZrO3 refractory with Y2O3 additive and its interaction with titanium melts

Abstract

Two kinds of refractory (BaZrO3 and Y2O3 (Y)-doped BaZrO3) were prepared to melt two titanium alloys (TiNi and Ti2Ni), respectively. The influence of Y2O3 on the phase constitution and microstructure of BaZrO3, as well as the interaction between the refractory and the titanium alloys, were investigated using the XRD and SEM. The results revealed that the Y-doped BaZrO3 consisted of BaZr1-xYxO3 and Ba2YZrO6-d, no erosion phenomenon was observed for two kinds of refractory after melting TiNi alloys, however, a 275 μm thick reaction layer of BaZrO3 crucible was observed after melting Ti2Ni alloy, whereas, there existed only a 45 μm erosion layer for the Y-doped BaZrO3 crucible. The dissolution of BaZrO3 in the titanium melts was the main reason of the alloy-crucible interaction, and the dissolution equation was determined: TixNi(l)+x2BaZrO3(s)→TixNi[x2Zr,xO](l)+x2BaO(l), doping Y2O3 into BaZrO3 could reduce the dissolution amount of refractory in the titanium melts by improving its thermodynamic stability. This fact may imply that the Y-doped BaZrO3 was more suitable for induction melting of the titanium alloys.