| 摘要 |
PURPOSE: To inexpensively obtain a carbon material having excellent resistance to oxidation by mixing B4 C fine powder and SiC fine powder, subjecting to a rubber press molding, baking to form a glassy protecting film on the surface in kneading carbon fine powder with a binder. CONSTITUTION: In kneading carbon fine powder having a grain size of <=12μm such as petroleum coke, carbon black or artificial graphite with a binder such as coal-tar pitch, SiC having a grain size of <=2μm is kneaded with B4 C of <=5μm in a mixing ratio of C: 76-40%, B4 C: 9-25% and SiC: 15-35%, molded in a rubber press method and baked at 700-100 deg.C to obtain a carbon material. A glassy protecting film is formed on the surface of the carbon material. The carbon material is coated with an aqueous solution of a mixture of glassy material, ceramic powder and metallic powder, heat-treated and dried to generate a glassy layer having a viscosity of 10<3> -10<7> P on the surface at an using high temperature to increase resistance to oxidation more. This carbon material is used as a protecting tube of a thermocouple for a molten metal.
|
