Interfacial microstructure of diamond/SiC composites fabricated by Si infiltration with gas flow guidance

Abstract

To preserve the structural and interfacial integrity of diamond, diamond/SiC composites were fabricated by Si infiltration under gas flow guidance. The characteristics of these materials are significantly affected by the interfacial reaction between Si and diamond. The interface formation was studied extensively by locally analyzing the microstructure of the interfacial regions via transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and X-ray diffraction (XRD). The results demonstrated that the extent of reactive erosion of diamond by Si weakened as the gas velocity increased during the infiltration process. Nanocrystalline Si5C3 and β-SiC grains with an orientation relationship were observed at the diamond/SiC interface. Furthermore, by employing gas flow guidance, the diamond/SiC composites exhibited a better specific stiffness, measuring up to 183.3 × 106 m2 s−2, which represents an exceptional 18 % improvement compared with the control group.