EFFECT OF OXIDES ON NUCLEATION BEHAVIOR IN SUPERCOOLED IRON.

Abstract

As part of a study of the effect of oxides on heterogeneous nucleation during solidification of iron, the degree of critical supercooling was measured on 300 g melts of electrolytic iron under a slag in a Tammann furnace. The degree of critical supercooling in heterogeneous nucleation was much lower than in homogeneous nucleation. With RE additions, it was 3 C, compared with 14 degree C for Al//2O//3 additions, 30 degree C for SiO//2 additions, and 53 degree C for MnO additions. The heterogeneous nucleation ″potency″ of oxides is related to the interfacial energy between the nucleation substrate and delta iron.