Abstract
Silicon carbide materials undergo an oxidation reaction in a high-temperature oxidizing environment and show different characteristics depending on the test temperature and time. In particular, the added oxides form a secondary phase within the sintering process and exhibit different oxidation characteristics depending on the added sintering materials. Therefore, to evaluate the oxidation characteristics, the weight of the test piece and the thickness of the oxidation layer were observed, and the structure and oxidation characteristics of the material were analyzed using SEM. SEM observation showed that an oxide layer was formed on the surface of the liquid sintered silicon carbide material after it was oxidized at 1200 ℃, 1300 ℃, and 1400 ℃ for 10 hours, respectively. Then, a bending test was performed at each temperature on the test piece with the oxidation layer formed to evaluate the change in flexural strength. The strength was 466.6 MPa at 1200 ℃, 363.1 MPa at 1300 ℃, and 350.8 MPa at 1400 ℃. Al2O3-SiO2 oxidized at 1200 ℃ for 10 hours showed an increase in strength of about 21.0 MPa compared to the data before the oxidation test.