Phase selection during rapid solidification of plasma-sprayed alumina splats on an alumina substrate

摘要

The nucleation and phase selection during rapid solidification of plasma-sprayed alumina on an alumina substrate at a high initial temperature was investigated theoretically by a model based on one dimensional heat transfer and the classic nucleation theory. The model involves under-cooling phenomenon, heterogeneous nucleation and kinetics. The effect of the substrate initial temperature on the phase selection of alumina splat was examined. Results clearly revealed that the only contact quality influences the nucleation temperature. The selection of the metastable phase is observed when the contact angle is high, and at a low contact angle less than 30°α phase is selected. The correlation with the observed results revealed that the effect of the substrate initial temperature on the phase selection of alumina splat is primarily based on the catalytic effect of the alumina substrate on crystalline nucleation of various phases in terms of the contact angle.