2009 Volume 117 Issue 1361 Pages 47-51
TiN-coated Al2O3 particles of different size, shape and crystal structure were prepared by depositing nano-size TiO2 on the Al2O3 surfaces from Ti(O-i-C3H7)4 solution (TiO2 precursor) by controlled hydrolysis, then nitrided with NH3 at 1000°C. Irrespective of the source of Al2O3 particles, a homogeneous TiO2 coating was achieved by heating from 10 to 40°C an ultrasonic suspension of the Al2O3 particles containing the precursor with 1.0 vol% H2O. After nitridation, the Al2O3 grains were coated with 10-20 nm TiN particles. Spark plasma sintering of the TiN/Al2O3 particles at 1500°C and 1600°C yielded the composite ceramics with a relative density of 94-97%. Composite TiN/Al2O3 ceramics with an electrical resistivity of ∼10-2 Ω cm were obtained at 25 vol% TiN composition.