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

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 microstruc-ture 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.