Method for forming a polycrystalline layer of ultra hard material

摘要

A polycrystalline diamond layer is bonded to a cemented metal carbide substrate by this process. A layer of dense high shear compaction material including diamond or cubic boron nitride particles is placed adjacent to a metal carbide substrate. The particles of diamond have become rounded instead of angular due to high shear compaction in a multiple roller process. The volatiles in the high shear compaction material are removed and binder decomposed at high temperature, for example, 950 DEG C., leaving residual amorphous carbon or graphite in a layer of ultra hard material particles on the carbide substrate. The substrate and layer assembly is then subjected to a high pressure, high temperature process, thereby sintering the ultra hard particles to each other to form a polycrystalline ultra hard layer bonded to the metal carbide substrate. The layer of high shear compaction material is also characterized by a particle size distribution including larger and smaller particles that are distributed uniformly throughout the layer.