Enhancing the thermal shock and corrosion resistance of low‐carbon Al₂O₃–C refractories: The role of h‐BN composite powder

Abstract

Developing low‐carbon and high‐performance Al2O3–C refractories is vital for extending the service life of slide gate plate refractories and reducing carbon emissions. In this study, hexagonal boron nitride (h‐BN) composite powder was prepared using the magnesiothermic reduction combustion synthesis route and introduced into low‐carbon Al2O3–C refractories. The phases composition, microstructure, mechanical properties, thermal shock, and slag corrosion resistance of low‐carbon Al2O3–C refractories were investigated. The results show that the thermal shock and slag corrosion resistance of low‐carbon Al2O3–C refractories enhanced by adding h‐BN composite powder. Due to the introduced h‐BN, consequent in situ formed spinel and AlN whiskers, the crack propagation in the refractories was deflected, branched forming more fine cracks, then the thermal shock resistance was enhanced. In addition to the chemical inertness of h‐BN, in situ formed spinel and AlN whiskers, the consequent decrease in pore size plays an important role in enhancing the slag corrosion resistance of the refractories. The h‐BN composite powder synthesized via the combustion synthesis in this study demonstrated potential application in high‐performance Al2O3–C slide gate plates used in continuous casting technology.