Patent ID: 8852546

Claim:
A method for making a diamond construction comprising the steps of: heating a volume of diamond grains to form graphite, wherein the diamond grains have a multimodal grain size distribution with an average particle size of greater than about 0.03 mm, and wherein the heating takes place in a vacuum environment; subjecting the volume of diamond grains to a high pressure/high temperature condition while the volume of diamond grains are positioned adjacent a metallic substrate comprising a catalyst material, wherein during the high pressure/high temperature condition the catalyst material infiltrates from the substrate into the volume of diamond grains to form a fully-sintered polycrystalline diamond body that is integrally joined to the metallic substrate; and treating at least a first region of the diamond body extending only a partial depth from a working surface to render the first region substantially free of the catalyst material while allowing the catalyst material to remain in an untreated second region of the diamond body, wherein the first region extends only a partial depth of from about 0.01 mm to 0.1 mm; wherein the metallic substrate is used to attach the diamond construction to subterranean drilling tool.