Highly electroconductive TiN/Si_3N_4 composite ceramics fabricated by spark plasma sintering of Si_3N_4 particles with a nano-sized TiN coating

摘要

Si_3N_4 particles coated with 20 nm TiN have been sintered by spark plasma sintering (SPS) at 1600 deg 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 Si_3N_4 particles plays a role in densification. Ceramics derived from TiN/Si_3N_4 composite particles containing 25 and 32.5 vol.% TiN posses continuous TiN networks in a Si_3N_4 matrix and their electrical resistivity is of the orderr of 1 X 10~(-4) omega cm, much lower than that of a mechanical mixtuer of nano-sized TiN particles and Si_3N_4 particles (1 omega m).