Pressureless Sintering of Boron Carbide-based Superhard Materials

摘要

Boron carbide-based materials B_4C-Me_xB_y were densified by pressureless sintering in avacuum furnace. Some transition metal carbides (TiC, ZrC, HfC, Cr_3C_2and WC) from groups IV-VI were used as sintering aids. The optimal sintering temperature in the range 2220-2250°C wasused for any composition. Here we show the possibilities to activate the mass transport of the B4Cby the mechanism of liquid phase sintering. The method of reactive sintering of B_4C in the presenceof additives of some transition metal carbides allows in situ synthesis of dense B_4C-Me_xB_ymaterials. Structural properties and fracture toughness of the B_4C-based composite materials werediscussed. The properties of some of these materials and the possibilities for their application arealso discussed.