Study on the oxygen diffusion in the oxide layers of SiBCN ceramics by SIMS

SiBCN, SiC and SiC-BN ceramics/composites were prepared by mechanical alloyed combined hot-pressing sintering at 1900 degrees C, and the oxidation kinetics of SiBCN, SiC and SiC-BN were calculated based on the thickness of oxide layers at 1100 similar to 1500 degrees C. The oxide layer can be divided into outer and inner parts under 1300 degrees C. At 1100 degrees C, the oxygen molecules diffused in SiC through the gaps in lattice, while diffused in SiBCN by substituting the O in SiO2. Moreover, BN(C) phase in SiBCN can slow down the generation rate of gases such as CO, N-2, NO2 and B2O3.

Automated summary

SiBCN, SiC, and SiC-BN ceramics/composites were prepared using mechanical alloying combined with hot-pressing sintering method. The oxidation kinetics of SiBCN, SiC, and SiC-BN were analyzed by calculating the thickness of the oxide layers. The results showed that the BN(C) phase in SiBCN can slow down the generation rate of gases.