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

Abstract

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°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 TiB2 content, hardness increased from 20.6 to 23.7 GPa and fracture toughness increased from 3.6 to 5.5 MPa m1/2. The electrical conductivity increased to a remarkable 2.72 × 103 (Ω 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.

Mechanism Analysis of Discharge Energy in the Electrostatic-Field-Induced Electrolyte Jet Micro-EDM

“…When the electric field intensity exceeds 1 × 10 6 V/m, the discharge can be generated in the air [30]. Figure 9 presents that the discharge energy increases with the growing interelectrode distance.…”

“…From Figure 9, it can also be found that the effective discharge distance of the interelectrode decreases with the increasing discharge concentration. When the electric field intensity exceeds 1 × 10 6 V/m, the discharge can be generated in the air [30]. Figure 9 presents that the discharge energy increases with the growing interelectrode distance.…”