The effects of impregnating graphite with the oxides and carbides of silicon, zirconium, boron, and chromium on its high-temperature oxidation characteristics were investigated. All of these impregnants reduced the oxidation rate except the carbide and oxide of chromium, which increased it. The impregnation was accomplished by quenching the heated graphite into a prepared solution. The data show that impregnation of graphite with the following materials is effective in promoting oxidation resistance in a decreasing order: (1) silicon carbide, (2) zirconium carbide, (3) boron oxide, (4) silicon dioxide, (5) zirconium dioxide, (6) boron carbide. With silicon carbide it was found that multiple quenching, up to three, improves oxidation resistance.
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