Enhanced oxidation resistance of low‐carbon MgO–C refractories with Al ₃ BC ₃ –Al antioxidants: A synergistic effect

The synergistic effects of Al 3 BC 3 –Al antioxidants on optimizing the oxidation resistance of low‐carbon MgO–C refractories were investigated. The results indicated that the oxidation index and rate constant of low‐carbon MgO–C refractories with optimized Al 3 BC 3 –Al additions were 13% and 1.10 × 10 −4 cm 2 min −1 at 1400°C for 3 h, respectively, which is much lower than that of Al or Al 3 BC 3 containing ones. Single Al 3 BC 3 is not a suitable antioxidant for low‐carbon MgO–C refractories; however, if Al 3 BC 3 was initially protected and Al reacted as the antioxidant, enhanced oxidation resistance at high temperature can be achieved. The formation of dense MgO–MgAl 2 O 4 –Mg 3 B 2 O 6 layer contributed to superior oxidation resistance, and the temperature for the generation of this layer was as low as 1100°C due to liquid and vapor phase–assisted reactions with Al 3 BC 3 –Al. Furthermore, a self‐repairing function was achieved at 1600°C with the combination of Al 3 BC 3 –Al additions in spite of the faster oxidation rate.