Ulterra Drilling Technologies, L.p.

John Martin Clegg

William Henry Dubose

Andrew David Murdock

Neal Alan Bowden

Matthew Douglas Mumma

A polycrystalline diamond compact (PDC), which is attached or bonded to a substrate to form a cutter for a drill bit, is comprised of sintered polycrystalline diamond interspersed with a seed material which has a hexagonal close packed (HCP) crystalline structure. A region of the sintered polycrystalline diamond structure, near one or more of its working surfaces, which has been seeded with an HCP seed material prior to sintering, is leached to remove catalyst. Selectively seeding portions or regions of a sintered polycrystalline diamond structure permits differing leach rates to form leached regions with differing distances or depths and geometries.

Diamond cutting elements for drill bits seeded with HCP crystalline material

The rate of leaching of a polycrystalline diamond (PCD) cutting layer for cutting elements or other wear parts is varied by introduction into the PCD of an additive prior to leaching. Selective introduction of the additive into one or more regions of a PCD cutting structure allows controlling leaching rates of selective leaching of parts of the PCD structure, which allows for creating of a boundary between the leached and non-leached regions of a PCD structure to be made so that is not parallel to the surface or surfaces exposed to the leaching solution. The additive is comprised of a material that increases the permeability of the PCD or acceptance of the PCD to the leaching solution, such as a hydrophile.

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Fort Worth, TX, United States of America

John Martin Clegg