Improvement of oxidation resistance property of C/SiCO nanoporous ceramic composites with TaSi2-MoSi2-ZrB2-borosilicate glass coating

To improve the oxidation resistance property of C/SiCO nanoporous ceramic composites, TaSi2-MoSi2-borosilicate glass coatings and TaSi2-MoSi2-ZrB2-Borosilicate glass coatings were prepared on the surface of C/SiCO nanoporous ceramic composites through slurry brushing combined with graphite powder embedding sintering process. The coatings are smooth, flat, without cracks, and tightly bonded to the substrate material. A study was conducted on the thermal stability of coated samples in an air atmosphere at 1600 degrees C and the high-temperature oxidation mechanism was analyzed. The results show that the coating effectively improves the thermal stability of SiCO nanoporous ceramic composites, and the addition of ZrB2 further improves the oxidation resistance and ablation resistance of the coated samples. At high temperatures, the borosilicate glass in the coating displays a viscous flow state, and the SiO2 glass layer formed on the coatings surface serves as an oxygen barrier. At the same time, the coating has a particle reinforced glass structure inside, which avoid the growth and propagation of cracks and reduce oxygen diffusion channels effectively.