Characterization of TiC ceramics with SiC and/or WC additives using electron microscopy and electron probe micro-analysis

Abstract

This investigation aimed to assess the discrete and synergic impacts of SiC whiskers (SiCw) and nano-sized WC (WCn) on the microstructure of TiC-based materials. Three dense specimens of TiC−3 wt% WCn, TiC−30 vol% SiCw, and TiC−30 vol% SiCw−3 wt% WCn were yielded using the spark plasma sintering (SPS). The X-ray diffraction patterns (XRD), as well as the microstructural observations, suggested unreactive sintering processes; however, thermodynamic studies showed that some minor chemical interactions could take place, leading to surface oxide removal. Furthermore, the field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) micrographs, as well as the field emission electron probe micro-analyzer (FEEPMA) images, proved the WCn dissolution into the TiC matrix, forming (Ti,W)C solid solution in the TiC-WCn and TiC-SiCw-WCn ceramics, and also the graphite precipitation from the TiC in all samples. Glassy SiO2 phase, available as the surface oxide of starting SiCw or produced as the in-situ phase, could form some amorphous interfaces in the relevant composites.