Anti-oxidation performance of mini SiC/SiC composites containing ZrSiO4 multilayer interphase

Mini SiC/SiC composites with ZrSiO4 containing 0-4 sublayers as interphase were fabricated. The prepared specimens were treated severally at 600 degrees C-1000 degrees C in air environment. The oxidation resistance effect and antioxidant mechanism of the ZrSiO4 interphase in the prepared composites were investigated according to their tensile strength and microstructures. Results indicated that mini SiC/SiC composites with ZrSiO4 containing 0-4 sublayers as interphase presented different variation trend of the tensile strength at different oxidation temperatures. Due to the slow reaction kinetics of the SiC pyrolyzed from PCS at 600 degrees C, the ZrSiO4 interphase did not make an obvious antioxidant effect. In contrast, owing to the more rapid reaction kinetics of SiC pyrolyzed from PCS at temperatures higher than 800 degrees C, the generated SiO2 bonded the SiC fibers and ZrSiO4 interphase together, which provided antioxidant protection for the SiC fibers. Therefore, the multilayer ZrSiO4 interphase only plays an obvious antioxidant role at temperatures higher than 800 degrees C.