Improving thermal stability of SiC whiskers via nanoscale Ti3SiC2 coatings

Effects of SiC whiskers (SiCw) on the mechanical properties of composites largely depend on their thermal stability at high temperature. In this study, pure SiCw and Ti3SiC2 coated SiCw were thermal treated at 1600-1800 degrees C for 1 h. Their phase assemblage, morphology, and structural evolution were investigated. Oxygen partial pressures in the graphite furnace resulted in the breakdown of SiCw into particles at 1600 degrees C, and the degradation became more pronounced with temperature increasing. The thermal stability of SiC whiskers at 1600-1700 degrees C was significantly improved by a thin Ti3SiC2 coating on them, as both thermodynamic calculations and experimental observations suggest Ti3SiC2 coating could be preferentially oxidized/decomposed, prior to the active oxidation of SiC. At 1800 degrees C, the protective role of the coating on the whiskers became weakened. SiC was converted into gaseous SiO and CO, with the remaining of interconnected TiC micro-rods and amorphous carbon.

Automated summary

The thermal stability of SiC whiskers on the mechanical properties of composites is crucial. The introduction of a thin Ti3SiC2 coating on SiC whiskers significantly improves their thermal stability at 1600-1700 degrees Celsius.