Mechanism study on improving corrosion resistance of BaZrO3-Yb2O3 composite refractories to GH4169 superalloy melt

To address the issue of poor corrosion resistance for pure BaZrO 3 refractory, BaZrO 3 -Yb 2 O 3 composite refractory was designed and prepared in this study. The wettability of high-temperature alloy melt on the composite refractory, the interfacial reaction mechanism and the physical properties of the material were systematically studied. The wetting experimental results show that the wettability of the high temperature alloy melt on the surface of the BaZrO 3 -Yb 2 O 3 composite refractory is lower than that on the pure BaZrO 3 refractory. This phenomenon can be attributed to the synergistic effect of higher surface roughness and the better thermodynamic stability of the BaZrO 3 -Yb 2 O 3 composite refractory. The results of vacuum induction melting experiments show that the interfacial reaction products of the two refractory crucibles and the superalloy melt are ZrO 2 and BaAl 2 O 4 . Owing to the higher thermodynamic stability of BaZrO 3 -Yb 2 O 3 composite refractory, the thickness of the interfacial reaction layer between the BaZrO 3 -Yb 2 O 3 composite refractory and alloy melt is significantly reduced, which is about 1/3 of the thickness for the interfacial reaction layer than pure BaZrO 3 refractory. In addition, the yield strength of the GH4169 alloy melted in the BaZrO 3 -Yb 2 O 3 crucible is approximately 30% higher than that melted in the pure BaZrO 3 crucible. This is mainly due to the less consumption of the Al element during the reaction process between composite refractory and alloy melt, which increases the content of auxiliary strengthening phase in the alloy more, and thereby optimizes the mechanical properties of the alloy. Meanwhile, the thermal conductivity of the BaZrO 3 -Yb 2 O 3 composite refractory is reduced by approximately 45%, while the compressive strength is nearly doubled, which can effectively reduce the heat loss during the smelting process and significantly prolong the service life of the refractory. This study provides a new technical strategy and theoretical support for solving the technical problems of smelting of GH4169 alloy.