摘要 |
<p>Porous refractory articles resistant to degradation at high temperatures for example by oxygen, chlorine and the like, are composed of a main body of a porous sintered carbide, nitride, boride or silicide which is coated with silicon nitride or silicon oxynitride. The coating is not only on the surface of the main body of the porous refractory article, but also penetrates the article to a depth at least greater than the depth of the surface pores.</p> |