THE EFFECT OF AN ELECTRIC-FIELD ON SELF-SUSTAINING COMBUSTION SYNTHESIS .2. FIELD-ASSISTED SYNTHESIS OF BETA-SIC

Self-sustaining combustion synthesis of beta-SiC is shown to be possib le in the presence of an electric field. Above a threshold field of si milar to 6.8 V . cm(-1), a combustion wave resulting from the reaction between silicon and graphite powders can be self-sustaining. A linear relationship between the applied field and the measured wave velocity is observed, in qualitative agreement with the model (as discussed in the previous article). At relatively high fields, >21 V . cm(-1) simu ltaneous combustion occurs. Microstructural examinations of quenched c ombustion fronts provided evidence of melting of the Si reactants. Thi s experimental work provides evidence of the validity of a model in wh ich chemical and electrical heat generation are contributing inside th e combustion front.