Superhard Nanophase Cutter Materials for Rock Drilling Applications

40979 November 19, 1996 Diamond Materials, Inc. This project will fabricate a new class of "binderless" polycrystalline diamond compact (PDC) rock cutters, in which (1) a thin piece of the PDC material is bonded to a nanophase tungsten carbon/cobalt (WC/Co) substrate, and (2) a solid piece of binderless PDC material is inserted into a nanophase WC/Co tool holder. The hardness and toughness of the binderless PDC material are expected to at least match, if not exceed, those of natural polycrystalline diamond (carbonado), and be stable up to temperatures of at least 1200oC. This should enable higher rock cutting rates and ensure longer cutter lifetimes. Phase I will focus on high pressure/high temperature sintering of "sub-micron sized" diamond powder, with the objective of obtaining a sintered PDC product that has superior fracture toughness, because of the expected smaller sintered grain size. In Phase II, this effort will be expanded to include ultra-high pressure consolidation of "nanocrystalline" diamond and "fullerene" powders. In addition, Phase II will fabricate several drag bits for performance testing in a fully instrumented drill rig. Anticipated Results/Potential Commercial Applications as described by the awardee: The availability of such cutters would yield significant economic benefits in oil and gas exploration, coal mining, and minerals extraction.