Phase and microstructural evolution of BaZrO ₃ ‐CaZrO ₃ refractory and its interaction with titanium alloy melt

Abstract In this study, the effect of CaZrO ₃ additives on the phase and microstructure of BaZrO ₃ refractory were investigated as well as the interaction with titanium alloy melts. Results revealed that no second phase was observed in the BaZrO ₃ refractory with 10 and 20 mol% CaZrO ₃ additives, respectively, and the incorporation CaZrO ₃ additives promoted the densification and the growth of grains due to the generation of BaZrO ₃ ‐CaZrO ₃ solid solutions. Whereas, the appearance of CaZrO ₃ phase was in the BaZrO ₃ refractory with 30 mol% additive, indicating that the additive content excessed the solid solubility limit in the BaZrO ₃ refractory. Interaction analysis indicated that CaZrO ₃ additive could improve the performance of BaZrO ₃ refractory for resisting the penetration of Ti ₂ Ni alloy melt. Meanwhile, an increasing extent of melt contamination by the BaZrO ₃ refractory was also detected with the increasing content of CaZrO ₃ additive. According to the thermodynamic calculation, an obvious increase in Gibbs free energy of formation for the BaZrO ₃ refractory was confirmed with the CaZrO ₃ additive, resulting in the increasing extent of the dissolution‐corrosion between the refractory and the titanium alloy melts.