Carbon and ceramic-containing layers for use in sintering of silicon nitride article

摘要

Sintering of an article molded from a first particulate material comprising silicon nitride employs carbon and ceramic-containing layers. At least one outer layer comprising a second particulate material is positioned with respect to the article so as to be closely adjacent to but not contacting the article, and at least one inner layer comprising a third particulate material is intermediate to the outer layer and the article so as to at least partially surround the article. The second particulate material comprises at least about 90 weight percent carbon, and the third particulate material comprises a ceramic compound selected from a nitride, a carbide, and mixtures thereof. The article is heated while positioned with respect to the outer and inner layers as described above so as to result in a sintered article.