Reactive sintering of B4C-TiB2 composites from B4C and TiO2 precursors

Abstract

The effect of sintering temperature in the interval from 1775 to 1850 °C on the density, microstructure, hardness and fracture toughness of ceramic composites consisting of a boron carbide matrix and titanium diboride secondary phase was studied. The composites were hot pressed using in situ reaction between boron carbide and 40 wt.% of titanium dioxide additive. The samples were hot pressed at different temperatures but for the constant time of 60 min, under the pressure of 35 MPa in vacuum of 10 Pa. Both Vickers hardness and fracture toughness of the composites increased with the sintering temperature. Maximal hardness of 29.8 GPa and fracture toughness of 6.9 MPa·m1/2 were achieved for the composite with 29.6 vol.% of titanium diboride secondary phase sintered at the highest sintering temperature of 1850 °C.