Kinetics Model for the Growth of Silicon Carbide by the Reaction of Liquid Silicon with Carbon

The kinetics and mechanism of reaction of glassy carbon with a pure silicon melt or a Si + Mo melt were investigated. The results showed that the growth of a continuous reaction‐formed SiC layer followed a fourth‐power rate law in the temperature range of 1430° to 1510°C. A model that could explain the fourth‐power rate law was developed. In this model, an internal electric field was assumed to be set up over the reaction‐formed SiC layer through a negative space charge, and then the diffusion of the carbon‐ion vacancies across this layer, driven predominately by this electric field, was considered as the rate‐limiting step for the SiC growth. Neither an increase in the processing temperature nor an addition of 10 wt% Mo into the silicon melt had a significant influence on the reaction kinetics. X‐ray diffraction analysis revealed that the reaction products were β‐SiC, and β‐SiC + MoSi 2 for the Si‐C and Si‐C‐Mo reactions, respectively.