Effect of Porosity on the Rate of Thermal Oxidation of Silicon Carbide Ceramics Produced by Spark Plasma Sintering

The process of high-temperature oxidation of silicon carbide-based ceramic materials synthesized by spark plasma sintering without any sintering-activating additives has been studied. Analysis of the microstructure of the oxidized ceramic samples and the data on the change in their mass indicate the formation of a protective SiO₂ layer on the SiC surface, which is characteristic of passive oxidation of silicon-containing oxygen-free compounds. The results of the comparative study of oxidation of the SiC ceramic samples with different porosity in air at a temperature of 1200°C have revealed a linear relationship between the growth rate of the oxidized sample mass and the volume of open pores in the sample.