REGULARITIES OF ELECTROSPARK SINTERING OF COMPOSITES OF SIC - TIC, SIC - VC SYSTEMS

Abstract

The kinetic regularities of electric spark sintering of SiC-TiC, SiC-VC composites at a pressure of 45 MPa and temperatures of 1900 and 2000 °C have been established. At the first stage of the composite compaction process, the addition of TiC, VC impurities in the amount of 20 vol.% to silicon carbide with a dispersion of 2 μm increases the compaction rate by 1.3 and 1.1 times, respectively, the addition of Ti, V carbides in the amount of 40 vol.% increases the compaction rate by 1.7 and 1.2 times, respectively. At the second stage of the compaction process, when Ti, V carbides are added in the amount of 40 vol.%, the compaction increases from 70 % in silicon carbide to 99.9 % in the 60 SiC-40 TiC composite and 91.2 % in the 60 SiC-40 VC composite. Solid-phase sintering in composites with an admixture of titanium carbide is better than in composites with an admixture of vanadium carbide due to an increase in interaction at the phase boundaries: the interaction zone increases from ~ 1.0 μm at the boundaries of silicon carbide and vanadium carbide grains to ~ 1.5 μm at the boundaries of silicon carbide and titanium carbide grains.