Enhancement of oxidation resistance at 1000-1400 °C of low carbon Al2O3-C refractories with pre-synthesized SiCnw/Al2O3

The oxidation resistance of low carbon Al2O3-C refractories with the addition of SiCnw/Al2O3 composite powders and the enhancement mechanisms were investigated. The oxidation resistance was evaluated by oxidation index (O.I.) and oxidation rate constant (k). The enhancement mechanisms of SiCnw/Al2O3 on oxidation resistance were analyzed based on the phases and microstructures. The results showed that the SiCnw/Al2O3 can improve the oxidation resistance of Al2O3-C refractories, the O.I. and k of A6 (6 wt% SiCnw/Al2O3 addition) were 26.0% and 34.5% lower than those of reference sample A0, respectively. The oxidation resistance of refractories was improved in a range of 1000-1400 degrees C due to the introduction of SiCnw/Al2O3. The enhancement mechanisms can be explained that SiCnw is more susceptible to be oxidized due to its high specific surface area, which expanded the action temperature range of other antioxidants and itself. The mullite and dense protective layer generated during oxidation is also beneficial to impede the diffusion of O-2.