Substantially pore-free shaped articles of polycrystalline silicon carbide, and a process for their manufacture by isostatic hot-pressing

摘要

The invention is substantially pore-free shaped articles consisting essentially of polycrystalline silicon nitride and polycrystalline silicon carbide in the form of a homogeneous microstructure having grain sizes of not more than 10 mu m manufactured from mixtures of Si3N4 powder and SiC powder in a weight ratio of from 5:95 to 95:5 without the concomitant use of sintering aids by isostatic hot pressing in a vacuum-sealed casing at temperatures of from 1800 DEG to 2200 DEG C. and a pressure of from 100 to 400 MPa.