Abstract
Chromium carbides (Cr 3C 2, Cr 7C 3 and Cr 23C 6) have been synthesized and consolidated simultaneously from mixtures of Cr and amorphous carbon powders by pulsed electric-current pressure sintering (PECPS). Dense ceramics thus obtained were composed of chromium carbides with a small amount of Cr 2O 3, which originates from a trace amount of oxygen adsorbed on the as-received starting Cr powder. Synthesis and consolidation processes, which were observed from their shrinkage curves during PECPS, have been examined using X-ray diffraction (XRD) and scanning electron microscopy for the powder compacts. Cr 3C 2 ceramics sintered at 1300 °C for 10 min under 30 MPa have a 98.9% of theoretical density and fine structures with a 3.6 μm grain size. They exhibit excellent mechanical properties: a bending strength σ b of 690 MPa, a Vickers hardness H v of 18.9 GPa and a fracture toughness K IC of 7.1 MPa m 1/2.
Published Version
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