1989 Volume 29 Issue 11 Pages 966-972
Our previous research suggests that the interfacial segregation of S during high temperature oxidation is detrimental to the adherence of oxide scale to metal substrate. But the effect of S is often perturbed by other complex factors affecting the scale adherence. In this work the surface segregation of S and the spalling of Al2O3 coating layer were examined on 18 sorts of alloys with and without REM doping or Y2O3 dispersion. It was found that the segregated S promotes the spalling of Al2O3 coating lager, and that REM and Y2O3 suppress concurrently the segregation of S and spalling of Al2O3 coating layer. These detrimental effect of S and suppression effect of REM were confirmed much more clearly on Al2O3 coating layer than oxide scale. On the other hand P had no detrimental effect on the adherence. For practical coating technique it is recommended to suppress the segregation of S. The difference in the effect between REM and Y2O3 will be discussed.
