Intrinsic reaction and self-diffusion kinetics for silicon carbide synthesis by rapid carbothermal reduction

A one-dimensional nonisothermal model has been developed for the "rapid carbothermal reduction" synthesis of fine silicon carbide powders. Intrinsic reaction and self-diffusion kinetics are identified through simulation of the model and comparison to experimental results. The reaction rate follows a shrinking-core mechanism and is described by the relation k(s-1) = (2.8)/d(p)(o) exp((-3.4 x 105)/(RTm)) The self-diffusion coefficient for SiC in the aerosol flow reactor is described by the relation D*(m(2)/s) = 1.4 x 10(-5) exp ((-4.46 x 105)/(RTm)).