Development of spark plasma sintered conductive SiC–TiB 2 composites for electrical discharge machining applications

Highly dense electrically conductive silicon carbide (SiC)–(0, 10, 20, and 30 vol%) titanium boride (TiB 2 ) composites with 10 vol% of Y 2 O 3 –AlN additives were fabricated at a relatively low temperature of 1800°C by spark plasma sintering in nitrogen atmosphere. Phase analysis of sintered composites reveals suppressed β→α phase transformation due to low sintering temperature, nitride additives, and nitrogen sintering atmosphere. With increase in TiB 2 content, hardness increased from 20.6 to 23.7 GPa and fracture toughness increased from 3.6 to 5.5 MPa m 1/2 . The electrical conductivity increased to a remarkable 2.72 × 10 3 (Ω cm) –1 for SiC–30 vol% TiB 2 composites due to large amount of conductive reinforcement, additive composition, and sintering in nitrogen atmosphere. The successful electrical discharge machining illustrates potential of the sintered SiC–TiB 2 composites toward extending the application regime of conventional SiC‐based ceramics.