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 Al 2 O 3 –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 Al 2 O 3 –C refractories. The phases composition, microstructure, mechanical properties, thermal shock, and slag corrosion resistance of low‐carbon Al 2 O 3 –C refractories were investigated. The results show that the thermal shock and slag corrosion resistance of low‐carbon Al 2 O 3 –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 Al 2 O 3 –C slide gate plates used in continuous casting technology.