Stability of oxide crucibles and implications for the fabrication of Zr-based bulk metallic glass master alloys

In this study, a systematic evaluation was conducted on the performance of Al2O3, MgO, BaZrO3 and Y2O3 crucibles for melting Zr-based bulk metallic glass master alloys. The interaction between the crucibles and the alloy melts was investigated, focusing on the effect of crucible type and the addition of Y element on the interaction. The results indicated that the relative stability of the evaluated oxide crucibles, in order of decreasing interaction extent, followed the sequence: MgO -> Y2O3 -> Al2O3 -> BaZrO3. The grading did not follow the free energy data of the formation of these oxides. It was because that the Y combined with O in the alloy melts to form Y2O3 products, which adhered to the inner surface of the crucible. This further prevented the dissolution of the crucible refractory. Among the tested crucibles, the Y2O3 product layer exhibited the most complete structure on the surface of BaZrO3 crucible, thereby minimizing both the corrosion of the crucible and the contamination of the alloy melts.