Formation mechanism and supersonic flame erosion behavior of SiC and SiC-SiC_(nano) single-layer oxidation protective coatings for carbon materials by reactive melt infiltration (RMI) method

摘要

In this study, chemical and mechanical erosion mechanism of SiC single-layer coatings were evaluated using supersonic flame erosion test, X-ray diffraction, and scanning electron microscopy. In the first step, the formation mechanism of SiC coating on graphite substrate was investigated by HSC Chemistry software version 6.0 and then the effects of infiltration temperature and SiC nanoparticles addition on erosion behavior of the coatings were studied. The results of erosion test under supersonic flame at a 90 degrees angle after 120 s indicated that chemical and mechanical erosion occur simultaneously during erosion test but mechanical erosion is the dominant mechanism which causes to sample destruction. However, with SiC nanoparticles addition and increasing the infiltration temperature, mechanical erosion decreased. By increasing of infiltration temperature, mass erosion rate and linear erosion rate decreased from 2.52 x 10(-3) g cm(-2) s(-1) and 32.7 mu m s(-1) to 1.09 x 10(-3) g cm(-2) s(-1) and 3.33 mu m s(-1) respectively. Also, with addition of SiC nanoparticles, mass and linear erosion rate decreased from 2.52 x 10(-3) g cm(-2) s(-1) and 32.7 mu m s(-1) to 1.04 x 10(-3) g cm(-2) s(-1) and 2.17 mu m s(-1) respectively.