Strengthening mechanism and slag corrosion-resistance of low-carbon Al2O3–C refractories: Role of h-BN

Abstract

The corrosion resistance of low-carbon Al2O3–C refractories was improved by a novel preparation method to satisfy the requirements of a newly developed smelting process. Improving the corrosion resistance of Al2O3–C refractories is crucial for extending the service life of industrial furnaces and reducing carbon emissions. In this study, the effects of graphite-like h-BN on the microstructure, mechanical properties and corrosion resistance of low-carbon Al2O3–C refractories were investigated. The results shows that the mechanical properties of low-carbon Al2O3–C refractories can be improved by adding h-BN. This was due to the fact that the microstructure of the material was regulated by h-BN to form the Sialon structure of the folded space. Simultaneously, the corrosion resistance of low-carbon Al2O3–C refractories was enhanced by h-BN, resulting in an increase of up to 70.3 %. According to phase change and microstructure analysis, the introduction of h-BN was beneficial to avoid the formation of decarbonized layer and promote the continuous structure precipitation of Al8B2O15, spinel and anorthite. This change promoted the densification of the slag/refractories interface, thereby hindering the corrosion of the slag. Thermodynamic simulations verified that by introducing h-BN, the generation of the high-melting-point material was increased and the absolute content of each phase material was reduced. As a result, the low-carbon Al2O3–C refractories exhibited enhanced corrosion resistance.

Keywords

• Corrosion-resistance
• h-BN
• Low-carbon Al2O3–C refractories
• Microstructure
• Thermodynamic simulation