Materials based on nanosized β-Si3N4 composite powders

Nanomaterials offer the possibility to improve properties like hardness, wear resistance or offer some advantages in production and microstructure formation. The commercial realisation of such materials depends on the one hand on the realisation of improved properties, on the other hand on realisation of the production of powders having constant properties with acceptable prices, as well as reproducible processing. The use of nonoxide nanopowders request additionally a careful control of the oxygen content. In this paper the concept of production of nano beta-Si3N4 composite powders containing besides the nano crystallites of beta-Si3N4. also the grain boundary phase, their processing and resulting micro structures are discussed. The grain boundary phase coating the surface of the powders protect them from further hydrolysis. This possibility allows the production of nanostructured Si3N4-ceramics or composites. The densification of such powders, microstructures and properties will be explained. (C) 2003 Elsevier Ltd. All rights reserved.