Erosion behaviors of BaZrO3 and BaZrO3/Y2O3 dual-phase refractories within Nb–Si melts during vacuum induction melting

Abstract

To develop a potential refractory for preparing Nb–Si alloy, the Nb–16Si (at.%) alloy was melted using BaZrO3 and BaZrO3/Y2O3 dual-phase crucibles through vacuum induction melting (VIM). The interfacial behavior of BaZrO3 and BaZrO3/Y2O3 dual-phase refractories against Nb–16Si alloy melts was investigated by utilizing scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). The results show that the improved performance of the BaZrO3/Y₂O₃ crucible can be attributed to Y replacing Zr in BaZrO3, forming a BaZr1-xYxO₃ solid solution. The Gibbs free energy of BaZr1-xYxO₃ is lower than that of BaZrO3, indicating higher thermodynamic stability. Furthermore, Y2O3 acted as a barrier, isolating BaZrO3 from the Nb–16Si melts. The dissolution of BaZrO3 was the primary mechanism of crucible erosion. The thickness of erosion layer of BaZrO3 crucible caused by Nb–16Si melts was about 186 μm, while the erosion layer of BaZrO3/Y2O3 dual-phase crucible was negligible, resulting in alloy ingots with significantly lower contamination. The BaZrO3/Y2O3 dual-phase refractory exhibited superior high-temperature stability to Nb–16Si melts compared with BaZrO3.

Keywords

• Nb-Si alloy
• Barium zirconate
• Yttrium oxide
• Dual-phase refractory
• Interfacial behavior