Abstract: Reaction vessel construction is provided whereby in the practice of the invention disclosed in U.S. Pat. No. 3,297,407 - Wentorf, Jr. diamond seed material is isolated from the main supply of catalyst-solvent metal by an inert barrier insoluble in the catalyst-solvent bath. One or more restricted diamond growth paths (e.g. small diameter wires of catalyst-solvent) are provided through the inert barrier interconnecting diamond seed material and the main supply of catalyst-solvent metal. In this way the diamond seed material cannot be eroded or destroyed by exposure to the bath of catalyst-solvent metal and a controllable limit can be placed on the size of the single diamond seed crystal ultimately presented to the bath via any given growth path.

Abstract: Extensive development of deformation bands in diamond crystals results from subjecting diamond material properly confined to reduce or eliminate brittle fracture thereof to the simultaneous application of high pressure and temperature in a defined region on the carbon phase diagram, the pressures and temperatures being incapable of bringing about significant crystal-to-crystal bonding of diamond. Plastic deformation resulting in work-hardening of these diamonds can be made to occur at temperatures as low as 900.degree. C. at pressures of about 60 kb. A work-hardened diamond for use in a single-point diamond tool would, for example, be prepared by embedding the diamond in diamond powder to fill the volume thereby inhibiting brittle fracture of the diamond being work-hardened.

Abstract: At a heat source, such as a nuclear reactor, methane and carbon dioxide are reacted (at about 800.degree.-900.degree.C) to form a mixture of carbon monoxide and hydrogen. This mixture of gases is cooled by heat exchange with incoming cold CH.sub.4 and CO.sub.2 and is then pumped through a first pipeline at ambient temperature to an energy use area. At the energy use end of the first pipeline the gas mixture is heated (to about 350.degree.-500.degree.C) in the presence of steam and a catalyst. The CO and H.sub.2 react exothermically to form CH.sub.4 and CO.sub.2. The heat evolved from this reaction is released across a heat exchanger for use as process heat or for conversion to electricity. Water is condensed and separated from the mixture of gaseous reactants and the dried, cooled CH.sub.4 /CO.sub.2 mixture is returned to the heat source end via a second pipeline for repetition of the closed loop process described.

Abstract: Diamond tools and superpressure processes for the preparation thereof are described wherein the diamond content is present either in the form of a mass comprising diamond crystals bonded to each other or of a thin skin of diamond crystals bonded to each other. In each instance the diamond content is supported on and directly bonded to an extremely stiff sintered carbide substrate in order to provide mechanical support therefor to more effectively utilize the high elastic modulus of the diamond.The questions raised in reexamination request No. 90/000,610, filed Aug. 15, 1984, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).