Compaction of nanodiamonds produced under detonation conditions and properties of composite and polycrystalline materials made on their basis

It is believed that materials based on ultrafine (nanoscale) diamond powders can possess high-level physical-mechanical and performance parameters characteristic of a nanocrystalline state. In certain cases, however, conventional methods for compacting ultrafine-dispersed diamonds (UDDs) fail and cannot be used to fabricate materials with desired properties. The difficulties associated with the ultrafine-dispersed state of the initial diamond powders can be surmounted by modifying the chemical and phase composition of the UDD surface. The possible use of UDDs as a catalyst that is conductive to the occurrence of chemical and phase transformations in certain substances at high pressures is analyzed. Sintering UDDs in the region of metastability of diamond makes it possible to produce porous polycrystalline aggregates with large specific surface area and very hard transparent particles. (C) 2004 MAIK "Nauka / Interperiodica".