Hardness and elastic moduli of high pressure synthesized MoB₂and WB₂compacts

Abstract

High pressure and high temperature synthesized MoB2 and WB2 compacts were investigated using X-ray diffraction, energy dispersive spectroscope, scanning electron microscope, Vickers indentation test and ultrasonic measurements. Experiments showed that both MoB2 and WB2 compacts are phase pure and with a grain size of 100–200 nm. Vickers indentation test under a large loading force of 49 N showed that the Vickers hardness of MoB2 and WB2 are about 21 and 22 GPa, respectively. The bulk modulus and shear modulus are about 296 GPa, and 190 GPa for MoB2 and 349 and 200 GPa for WB2 through ultrasonic measurements. Our results indicate that MoB2 and WB2 are both hard materials with a hardness similar to that of tungsten carbide, which is widely used in industry.