Processing and microstructure characterization of SiCp/Hastelloy(Ni-Mo-Cr) composites prepared by pressureless infiltration

SiCp/Hastelloy composites were fabricated by pressureless Ti-activated infiltration process. The wetting and infiltration behaviors of Hastelloy on the SiC substrates and the interfacial reaction between the SiC particles and Hastelloy were investigated by real-time observation system, X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy X-ray dispersive spectroscopy (EDS) system. The results demonstrated that the Hastelloy had a good wettability on SiC ceramic and could spontaneously infiltrate into the Ti-activated SiC preform. Moreover, intensive interfacial reaction similar to SiC/Ni system was found between the SiC particles and Hastelloy, which induced defects in the microstructure. In order to inhibit the interfacial reaction, Al2O3 coating on SiC particles was adopted as a diffusion barrier, which effectively reduced the extent of the interfacial reactions.