Low-temperature β-SiC interlayer for diamond film on cemented carbide

The adhesion of protective diamond films to cemented carbide substrates used in fabrication of space drilling tools can be improved by the inclusion of beta-SiC interlayers. Conventional CVD methods for depositing the SiC interlayers lead to interface coarsening and heat stress resulting from high temperatures of deposition. In this work, a mid-frequency magnetron sputtering technique is used to deposit the beta-SiC interlayer at lower temperatures, and the effects of deposition temperature on the microstructure and properties of the interlayer and final diamond film are assessed. The results show that the beta-SiC interlayers deposited at temperatures exceeding 300 degrees C possess high compactness and crystallinity. Increasing crystal beta-SiC phase has beneficial effects on the nucleation and growth of diamond film. Based on the experimental data, a six-step reaction model is proposed to show the mechanism by which the beta-SiC interlayer promotes the nucleation and growth of diamond films.