High‐temperature Na2SO4 deposit‐assisted corrosion of silicon carbide–II: Effects of B,C, and Si

The effects of boron, carbon, and silicon on the induced hot corrosion of sintered‐α (Hexoloy) and CVD‐SiC coupons were studied to elucidate the hot corrosion of SiC‐based ceramic matrix composites. The extent of corrosion was quantified after 24 hour exposures at 1000°C using mass change measurements, inductively coupled plasma optical emission spectrometry analysis of corrosion products, and optical profilometry of pitting on the substrate surface. In addition, scanning electron microscopy and X‐ray diffraction were used to better understand the morphology, distribution, and phase composition of corrosion products. It was found that Si was more resistant to hot corrosion than SiC, indicating that residual Si in a ceramic matrix composites matrix should not negatively impact hot corrosion resistance of the composite in highly oxidizing conditions. Carbon did not have a large impact on hot corrosion of SiC, whereas the presence of boron made the hot corrosion attack more severe.