POLYCRYSTALLINE CUBIC BORON NITRIDE (PCBN) COMPRISING MICROCRYSTALLINE CUBIC BORON NITRIDE (CBN) AND METHOD OF MAKING

摘要

Polycrystalline cubic boron nitride compact include a body having sintered microcrystalline cubic boron nitride in a matrix of binder material. The microcrystalline cubic boron nitride particles have a size ranging from 2 microns to 50 microns. The particles of microcrystalline cubic boron nitride include a plurality of sub-grains, each sub-grain having a size ranging from 0.1 micron to 2 microns. The compacts are manufactured in a high pressure - high temperature (HPHT) sintering process. The compacts exhibit intergranular defect formation following introduction of wear. The sub-grains promote crack propagation based on micro-chipping rather than on a cleavage mechanism and, in sintered bodies, cracks propagate intergranularly rather than intragranularly, resulting in increased toughness and improved wear characteristics as compared to monocrystalline cubic boron nitride. The compacts are suitable for use as abrasive tools.