Conditions for preparing large blanks of hexanite-R and their properties

Sintering of pure wurzitic boron nitride [99% (wt.) BN^sub w^] was performed under high static pressure at high temperature (P=8-9 GPa, T=1700-2000 K). The "double toroid" equipment is used at high pressure. Compact single- and two-layer plates 14-15 mm in diameter are fabricated. It is shown that sintering of BN^sub w^ is accompanied by the phase transformation BN^sub w^[arrow right]BN^sub sp^ (cubic boron nitride). The phase composition, microstructure, density, Young's modulus, and wear resistance during cutting are also studied. It is found that sintered materials have the same physical and chemical properties as the well-known superhard material Hexanite-R but due to the larger blank dimensions there are greater cutting possibilities.[PUBLICATION ABSTRACT]