Highly electroconductive TiN/Si3N4 composite ceramics fabricated by spark plasma sintering of Si3N4 particles with a nano-sized TiN coating

Si3N4 particles coated with 20 nm TiN have been sintered by spark plasma sintering (SPS) at 1600 °C. The 25 vol.% TiN ceramic achieved a relative density of 91% without sintering additives. TEM and HREM observations indicate that a glassy phase derived from the Si3N4 particles plays a role in densification. Ceramics derived from TiN/Si3N4 composite particles containing 25 and 32.5 vol.% TiN possess continuous TiN networks in a Si3N4 matrix and their electrical resistivity is of the order of 1 × 10−4 Ω cm, much lower than that of a mechanical mixture of nano-sized TiN particles and Si3N4 particles (1 Ω cm).