Facilitated synthesis of cubic boron nitride by a mechanochemical effect

摘要: Abstract A superhard cubic boron nitride (c-BN), which is now an industrially important material used in preference to diamond especially for cutting and lapping steel products, has so far been synthesized by heating a starting powder of hexagonal (h-BN) under high pressure at temperature. In the present study we have mechanically milled h-BN introduce lattice defects prior its conversion c-BN. The synthesis c-BN then facilitated prominently owing mechanochemical effect; 7.7 GPa formation starts 1250°C with pre-milled powders, 1450°C non-milled powders. High resolution transmission electron microscopy clarified that variety form during milling. changes w-BN compression c direction, slight tilt interface between (0002)h (0002)w partially compensates misfit basal planes both phases. Characteristic stacking ...