Исследование процесса компактирования нано- и микропорошков карбида кремния в аппарате высокого давления

The results of the investigation into compacting (sintering) in high-pressure apparatus of the DO-138 model of nanopowders and micropowders of silicon carbide are presented. Compacting modes for both types of materials were identical (pressure of 3.5–4.0 GPa, temperature of 1600–1700 °C, and holding time of 10 s). The influence of cladding the SiC nanopowders and micropowders with titanium and titanium nitride on the properties of compacts (cakes) fabricated in the same sintering modes is also considered. It is established that when compacting the silicon carbide nanopowder, the formed cakes differ by the higher density, hardness, and lower porosity compared with the samples of finely dispersed silicon carbide of technical grade. High activity of titanium with respect to SiC allows one to bond chemically the grains of the latter due to the formation of intermediate layers of titanium compounds between them. This is resulted in that the formed ceramics possesses high density, hardness, and wear resistance. Wear resistance of synthesized composites based on nano-SiC is higher by a factor of 4.5 than that one of polycrystalline material made of silicon carbide micropowder.