Improving oxidation resistance and fracture strength of MgO–C refractory material through precursor coating

An Al precursor was coated onto the surface of graphite in a MgO–C refractory material to improve the oxidation resistance and the fracture strength by controlling the amount of antioxidant and the coating thickness. To enhance the coating efficiency, the surface of the graphite used as the carbon source was treated with an acid. In oxidation tests, the Al-coated graphite showed a smaller weight loss than the pristine graphite. The MgO–C refractory material with the Al-coated graphite showed a similar fracture strength to that with commercial graphite, despite the use of a smaller amount of antioxidant. The highest fracture strength of the MgO–C refractory material was about 17 MPa; it was obtained with the Al-coated graphite. The increase in fracture strength was a result of the homogeneos coating of Al precursor in the modified MgO-C refractory material. Based on the properties observed, we discuss the relationship between fracture strength and process parameters.