Enhanced oxidation resistance of low‐carbon MgO–C refractories with Al3BC3–Al antioxidants: A synergistic effect

Abstract

AbstractThe synergistic effects of Al3BC3–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 Al3BC3–Al additions were 13% and 1.10 × 10−4 cm2 min−1 at 1400°C for 3 h, respectively, which is much lower than that of Al or Al3BC3 containing ones. Single Al3BC3 is not a suitable antioxidant for low‐carbon MgO–C refractories; however, if Al3BC3 was initially protected and Al reacted as the antioxidant, enhanced oxidation resistance at high temperature can be achieved. The formation of dense MgO–MgAl2O4–Mg3B2O6 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 Al3BC3–Al. Furthermore, a self‐repairing function was achieved at 1600°C with the combination of Al3BC3–Al additions in spite of the faster oxidation rate.