Effects of Nanometer Carbon Black on Performance of Low-Carbon MgO-C Composites

The low-carbon magnesia-carbon (MgO-C) composites containing 3% (mass fraction, the same below) carbon were prepared by adding various types of carbon black (CB). The mechanical properties, oxidation resistance at 1100 °C in oxidizing atmosphere, and thermal shock resistance after 5 times dipping in 1600 °C molten steel of the low-carbon composite samples were investigated, compared with a commercial high-carbon MgO-C composite containing carbon of 16%. The results show that the mechanical properties, oxidation resistance and thermal shock resistance of the low-carbon samples are improved with the decrease of CB particle size. Thermal shock resistance of the low-carbon sample containing nanometer CB N220 is obviously better than that of other low-carbon samples, and reaches the level of the high-carbon samples.