Microstructural and mechanical properties of microwave sintered bulk titanium nitride nanoceramics.

In the present work nano-sized TiN powders were consolidated and sintered in nitrogen, argon and air using microwave power of 900 W at frequency 2.45 GHz. Green compacts were exposed to microwave energy, and heated at an in-situ temperature of 1500 °C without holding time. The relative density achieved was ∼92 %. X-ray diffraction analysis showed presence of TiN as the dominant major phase. The microstructures indicate that the sintered samples retained their nanocrystallinty, though aggregates comprising clusters of nanoparticle was noticed with size in the range of 80–400 nm due to high heating rate. Micro indentation assessment indicates average Vickers hardness of 15.2 ± 0.5 GPa. The lengths of cracks originating from the indentation edges were measured; the indentation fracture toughness were obtained between 4.0 and 4.5 MPa.m1/2. The observed properties indicate the suitability of the sintered material in tribological applications. [Display omitted] • TiN ceramics without binders and additives was processed using microwave energy. • Use of SiC and graphite powder susceptors significantly reduced processing time. • Compacts sintered at high heating rate attained ∼92 % relative density. • Sintering was accomplished with comparable mechanical properties while retaining nanocrystallinity. [ABSTRACT FROM AUTHOR]