NANOCRYSTALLINE HIGH-MELTING POINT COMPOUND-BASED MATERIALS

The different preparation methods of ultrafine powders of high melting point compounds (carbides, borides, nitrides, and oxides with melting temperatures higher than 2000-degrees-C) are reviewed. Some propertie s of these powders are discussed and compared. The consolidation behav iour of these compounds in the nanocrystalline (nc) state is described in detail. Compaction by hot pressing, including high pressures and h igh temperatures, sintering, and high-energy consolidation methods, is analysed. The microstructure, recrystallization, mechanical and physi cal properties of nc-carbides, nitrides, and oxides are characterized. Special attention is focused on relationships between structure and p roperties.