Structure stability of Si-Zr-B coating and its nucleation inhibition effect on superalloy melt

A Si-Zr-B glass coating was prepared with shell-molding technique, sol-gel processing and dipping class heat treatment procedure. It is found that B₂O₃ can inhibit crystallization of Si-Zr-B coating. The XRD patterns of Si-Zr-B coating show that the amount of crystalline at 1500%deg;C is only 1-3%, indicating that the coating is of high structure stability. The under cooling testing for DD3 single crystal superalloy melt with Si-Zr-B coating was performed at as much as 140 K. The SEM micrograph and XRD pattern of the contacting surface between the superalloy melt and the coating, and morphology of DD3 single crystal superalloy after rapid solidification show that Si-Zr-B coating makes the rapid solidification of the superalloy melt possible, which means Si-Zr-B has a good nucleation inhibition effect on DD3 single crystal superalloy melt.