| 摘要 |
A film of a carbide of at least one of Ta, Nb, W, Hf, Mo and V is formed on the internal surface of a carbon container by heating the container having therein a mixture of the metal, sufficient to form a film at least 0.1 mil thick, and silicon in amount at least one quarter the weight of metal, in an inert atmosphere at a temperature sufficient to melt the mixture and react the metal with the carbon surface and to volatilize the silicon, but below the boiling point of the carbide film. The metal and silicon may be introduced as compounds, e.g. the metal halide and silicon tetrachloride which yield the metal and silicon and volatile by-products under the reaction conditions. The inert atmosphere may be e.g. neon or nitrogen or a reduced pressure of 10-4 to 10-6 mm. Hg. A one-stage heating process may be carried out within the range 2500-3000 DEG C. at atmospheric pressure or 2000-2500 DEG C at the above reduced pressure. Alternatively the mixture may be heated at a minimum of 1450 DEG C. to melt the mixture and form the metal carbide followed by heating at a higher temperature, up to 200 DEG C. below the boiling point of the film, e.g. about 3700 DEG C. to evaporate the silicon.ALSO:A film of a carbide of at least one of Ta, Nb, W, Hf, Mo and V is formed on the internal surface of a carbon container by heating the container having therein a mixture of the metal, sufficient to form a film at least 0.1 mil thick, and silicon in amount at least one quarter the weight of metal, in an inert atmosphere at a temperature sufficient to melt the mixture and react the metal with the carbon surface and to volatilize the silicon, but below the boiling point of the carbide film. The metal and silicon may be introduced as compounds, e.g. the metal halide and silicon tetrachloride which yield the metal and silicon and volatile by-products under the reaction conditions. The inert atmosphere may be e.g. neon or nitrogen or a reduced pressure of 10-4 to 10-6 mm. Hg. A one-stage heating process may be carried out within the range 2500-3000 DEG C. at atmospheric pressure or 2000-2500 DEG C. at the above reduced pressure. Alternatively the mixture may be heated at a minimum of 1450 DEG C. to melt the mixture and form the metal carbide followed by heating at a higher temperature, up to 200 DEG C. below the boiling point of the film, e.g. about 3700 DEG C., to evaporate the silicon. |
