Electrical percolation and infrared emissivity of pressureless sintered SiC-MoSi2 composites tailored by sintering temperature

SiC-MoSi2 composites with low electrical resistivity and high infrared emissivity were fabricated via pressureless sintering. The relationship between microstructure evolution and electrical behaviors along with infrared emission properties of the resulting composites is investigated at various sintering temperatures. The electrical resistivity undergoes two significant drops with increasing sintering temperature. Pore elimination bears responsible for the initial decrease in electrical resistivity. Transmission electron microscopy (TEM) observation manifests that the thinned amorphous layers at SiC/MoSi2 interface decrease grain boundary resistivity and allow for electrical percolation to occur when sintering temperature further rises. Additionally, increasing sintering temperature leads to a higher infrared emissivity owing to the formation of Mo4.8Si3C0.6 and the decreased boundaries. The lowest electrical resistivity of 7.2 Omega cm and the highest infrared emissivity of 0.721 are recorded for composite sintered at 2000 degrees C. Overall, SiC-MoSi2 composites exhibit a promising prospect as infrared source elements that must endure harsh environments.