Graphite, used as a carbon source in a conventional magnesia-carbon (MgO-C) refractory, was coated with an inorganic precursor to prevent the contact between graphite and oxygen. The coating layer thus generated could effectively protect graphite from oxygen, compared to common antioxidants. The coating reagent was composed of silicate and metal alkoxide, generally called the inorganic precursor, which modified the graphite surface. The modified graphite showed excellent stability at 1000 oC in an ambient atmosphere, whereas the graphite in a conventional MgO-C refractory reacted with oxygen and showed a significant weight loss. The coating reagent was coated uniformly on the graphite surface and it was very efficient in preventing the oxidation of graphite. Furthermore, the shape of prepared refractory samples remained fixed, even when the content of phenol resin was low. Consequently, ecofriendly MgO-C refractories with high oxidation resistance were successfully prepared by the coating of an inorganic precursor onto graphite.

Keywords: Inorganic precursor, Sol-gel reaction, Refractory, Graphite, Coating, Oxidation resistance.