Wettability and Interfacial Reaction between the K492M Alloy and an Al[sub.2]O[sub.3] Shell

In this study, wettability behavior and the interaction between the K492M alloy and an Al[sub.2]O[sub.3] shell were investigated at 1430 °C for 2~5 min. The microstructural characterization of the alloy–shell interface was carried out by optical microscopy (OM) and scanning electron microscopy (SEM). The results indicated that the interaction could cause a sand adhesion phenomenon affecting the alloy, and the attached products were Al[sub.2]O[sub.3] particles. In addition, the wetting angles of the alloys located on the shell were 125.2°, 109.4°, 97.0°, and 95.0°, respectively, as the contact time was increased from 2 to 5 min. Apparently, the wettability of the alloy in relation to the shell had a relationship with the contact time, where a longer contact time was beneficial to the permeation of the alloy into the shell and the interaction between the two components. No significant chemical products could be detected in the interaction layer, indicating that only the occurrence of the physical dissolution of the shell took place in the alloy melt.