| 摘要 |
<p>Refractory parts or articles, even of very large dimensions, and exhibiting improved resistance to thermal shock are made from a starting material of carbon particles mixed with silicon particles in a predetermined ratio which is suspended in a solution of a binder, after which the suspension is squirted into a precipitating liquid to coat the particles with the binder. The solids are then separated and dried, molded under slight pressure, and coked (at 800 - 1,000.degree.C), and then rapidly raised in temperature (to 1,400 1,600.degree.C) for formation of silicon carbide throughout the article. It is useful to add powdered silicon carbide and mix it in before the coking step and, also, to hold the heated body at a temperature somewhat below 1,400.degree.C long enough to remove temperature gradients within it, followed by rapid heating up to a carbide-forming temperature. The porous bodies thus formed can be heated to reduce porosity after the coking step by impregnation with a suspension of silicon powder in a resin, after which the body is again coked, or impregnation may be carried out on the completely fired body, with a liquid resin or a molten metal, after evacuation of the porous body and the application of pressure to the impregnating fluid.</p> |
