| 摘要 |
PURPOSE:To provide resistance to consumption due to oxidation and pickup resistance by press-molding a graphitic carbon material having specified bulk specific gravity, porosity, Shore hardness, graphitization degree and average grain size and by impregnating a mixed liq. consisting of magnesium phosphate and colloidal silica into the molded body. CONSTITUTION:A graphitic carbon material having 1.75-2 bulk specific gravity, 8-17% porosity, >=70 Shore hardness, >=0.6 graphitization degree and <=100mum average grain size is press-molded into the shape of a hearth roll for a heat treatment furnace. An impregnating agent prepd. by blending magnesium phosphate with colloidal silica is impregnated into the molded body to form a sealed surface layer contg. silica and having >=3mm. thickness. |
