Dual-functional application of Al2O3–B2O3 composite bubble in Al2O3–SiC–C castables as antioxidant and mechanical reinforcement agents

Abstract In the present work, the influence of low-cost self-synthesized Al2O3–B2O3 composite bubble on the oxidation resistance and mechanical properties of Al2O3–SiC–C (ASC) castables were investigated. The pre-fabricated composite bubble were characterized in detail. The properties of the ASC castables were measured, including their oxidation indexes, ambient and high-temperature mechanical properties, and microstructural evaluations. The results showed that the introduction of moderate contents of Al2O3–B2O3 composite bubble effectively improved the oxidation resistance and mechanical properties of the ASC castables by volumetric expansion, improved powder filling performance, and the in-situ formation of a high-strength whisker network in the high-temperature flowing liquid phase. These results demonstrated the dual-functional application of Al2O3–B2O3 composite bubble in ASC castables as antioxidants and mechanical reinforcements simultaneously.