Development of spark plasma sintered conductive SiC-TiB2 composites for electrical discharge machining applications

Highly dense electrically conductive silicon carbide (SiC)-(0, 10, 20, and 30 vol%) titanium boride (TiB2) composites with 10 vol% of Y2O3-AlN additives were fabricated at a relatively low temperature of 1800 degrees C by spark plasma sintering in nitrogen atmosphere. Phase analysis of sintered composites reveals suppressed beta ->alpha phase transformation due to low sintering temperature, nitride additives, and nitrogen sintering atmosphere. With increase in TiB2 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 x 10(3) (omega cm)(-1) for SiC-30 vol% TiB2 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-TiB2 composites toward extending the application regime of conventional SiC-based ceramics.

Automated summary

Highly dense electrically conductive silicon carbide-titanium boride composites with Y2O3-AlN additives were fabricated via spark plasma sintering in a nitrogen atmosphere. Increasing TiB2 content improved hardness and fracture toughness, while sintering in nitrogen atmosphere increased electrical conductivity of the composites.