Effects of SPS Mold on the Properties of Sintered and Simulated SiC-ZrB 2 Composites

Silicon carbide (SiC)-zirconium diboride (ZrB2) composites were prepared by subjecting a 60:40 vol% mixture of β-SiC powder and ZrB2 matrix to spark plasma sintering (SPS) in 15 mmΦ and 20 mmΦ molds. The 15 mmΦ and 20 mmΦ compacts were sintered for 60 sec at 1500 °C under a uniaxial pressure of 50 MPa and argon atmosphere. Similar composites were simulated using Flux ® 3D computer simulation software. The current and power densities of the specimen sections of the simulated SiC-ZrB2 composites were higher than those of the mold sections of the 15 mmΦ and 20 mmΦ mold simulated specimens. Toward the centers of the specimen sections, the current densities in the simulated SiC-ZrB2 composites increased. The power density patterns of the specimen sections of the simulated SiC-ZrB2 composites were nearly identical to their current density patterns. The current densities of the 15 mmΦ mold of the simulated SiC-ZrB2 composites were higher than those of the 20 mmΦ mold in the center of the specimen section. The volume electrical resistivity of the simulated SiC-ZrB2 composite was about 7.72 times lower than those of the graphite mold and the punch section. The power density, 1.4604 GW/m 3 , of the 15 mmΦ mold of the simulated SiC-ZrB2 composite was higher than that of the 20 mmΦ mold, 1.3832 GW/m 3 . The ZrB2 distributions in the 20 mmΦ mold in the sintered SiC-ZrB2 composites were more uniform than those of the 15 mmΦ mold on the basis of energy-dispersive spectroscopy (EDS) mapping. The volume electrical resistivity of the 20 mmΦ mold of the sintered SiC-ZrB2 composite, 6.17 × 10 -4 Ω cm, was lower than that of the 15 mmΦ mold, 9.37 × 10 -4 Ω ·cm, at room temperature.