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

The 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 x 10(-4) cm(2) min(-1) at 1400 degrees 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 degrees C due to liquid and vapor phase-assisted reactions with Al3BC3-Al. Furthermore, a self-repairing function was achieved at 1600 degrees C with the combination of Al3BC3-Al additions in spite of the faster oxidation rate.