Abstract:
Apparatus and procedures are presented for forging, or hot working bulk ceramics, including high temperature superconductors and other sensitive materials, under precisely controlled conditions of pressure, temperature, atmospheric composition, and strain rate. A capsule with massive end plates and an independent gas supply is located in a modified hot isostatic press (HIP). Essentially uniaxial deformation of a pre-compacted disc with forces of up to 500,000 Newtons (50 tons) and at temperatures of up to 1000 C. can be achieved. The separate gas supply to the capsule can maintain a specified gaseous atmosphere around the disc, up to the operating pressure of the HIP. The apparatus is designed to tolerate partial oxygen pressures of up to 20%.
Abstract:
The invention provides a method of making an abrasive compact using conventional compact synthesis conditions. The method is characterized by the use of an ultra-hard abrasive particle mass comprising at least 25 percent by mass of ultra-hard abrasive particles having an average particle size in the range 10 to 100 microns, and consisting of particles having at least three different average particle sizes, and at least 4 percent by mass of ultra-hard abrasive particles having an average particle size of less than 10 microns. The abrasive compact is preferably a diamond compact.
Abstract:
The present invention is directed to the production of single-crystal diamond consisting of isotopically pure carbon-12 or carbon-13. The product is believed to be like that diamond product in application Ser. No. 448,469, but is made by a different method. In the present invention, isotopically pure single-crystal diamond is grown on a single crystal substrate directly from isotopically pure carbon-12 or carbon-13. One method for forming isotopically pure single-crystal diamond comprises the steps of placing in a reaction chamber a single crystal substrate heated to an elevated CVD diamond-forming temperature. A gaseous mixture of hydrogen and a hydrocarbon of isotopically pure carbon-12 or carbon-13 is provided in the chamber. The gaseous mixture then is at least partially decomposed in the chamber to form an isotopically-pure single crystal diamond layer on the single crystal substrate disposed therein. The thus-formed isotopically-pure single crystal diamond layer optionally may be removed from the single crystal substrate. Another method for forming isotopically-pure single-crystal diamond comprises diffusing isotopically-pure carbon-12 or carbon-13 through a metallic catalyst/solvent under high pressure to a region containing a single crystal substrate to form an isotopically-pure single-crystal diamond layer on said single crystal substrate. The single crystal substrate is stable under the high pressure and elevated temperatures used during the diffusion process. The single crystal substrates optionally may be diamond, including the isotopically-pure single-crystal diamond films formed by the inventive method disclosed herein, thus forming multi-layered diamond structures.
Abstract:
Apparatus and methods are disclosed for the rapid generation of high hydrostatic pressures and the concurrent delivery of said pressures to a workpiece. The apparatus and methods comprise the rapid thermal expansion and vaporization of a volatile fluid. The volatile fluid is typically liquid argon and heated typically by means of a controllable electric heater, delivered to the workpiece typically by means of a pressure-rupturable membrane. The disclosed apparatus and methods permit the application of high hydrostatic pressures to commercial-scale workpieces, in an economic manner and with reduced cycle times.
Abstract:
A high pressure apparatus including a container internally provided with a cylindrical space capable of being closed, which container is constituted by a unitary member or an integral assembly of a plurality of members joined throughout its full axial length; a cotter member or a pin inserted radially in the container at one or both axial end portions of the container, which cotter member or pin serves as a structure for bearing an axial force induced by a high pressure load; and a plurality of flexible members wound round the outer periphery of the container axially of the latter to thereby exert a precompression on the entirety of the container.
Abstract:
A high temperature high pressure apparatus which comprises: an annular die having a straight cylindrical bore and a substantially conical face in adjacency outwards with each end thereof, a pair of tapered punches which are in opposed and axial alignment with the die so that a conical face of each punch is substantially in parallel with that of the die, a pair of inner gaskets, each of which is made of fired refractory and is arranged in direct abutment on the conical face of the punch and the bore of the die, a pair of outer gaskets, which are made of material of intermediate hardness level and is arranged in adjacency outside the inner gasket, and a pair of stopper rings of readily deformable but highly tough material and arranged in adjacency outwards to the outer gaskets.
Abstract:
Diamond-nondiamond carbon polycrystalline composites particularly useful as abrasives are made by sintering diamond particles at temperatures above about 1440*K but at pressures below which diamond is stable or metastable with respect to its conversion to graphite.
Abstract:
A method and apparatus for generating pressures wherein a highly anisotropic pyrolytic graphite body having its highest coefficient of linear thermal expansion in the direction of an axis thereof is confined in a pressing vessel together with a compactible material which is positioned along said axis. Heating of the anisotropic body expands the same along said axis to compress the compactible material. The pressing vessel is composed of a material having a low coefficient of thermal expansion relative to the anisotropic body. Preferably, the pressing vessel is composed of isotropic graphite, so that high pressures can be generated by furnacing the entire assembly at temperatures as high as 2200* C.
Abstract:
A method for leaching a PCD table for a cutter element includes (a) positioning a PCD table within a leaching chamber. The method also includes (b) submerging the PCD table in an acid within the leaching chamber. In addition, the method includes (c) sealing the leaching chamber. Further, the method includes (d) increasing the pressure within the leaching chamber to a pressure greater than or equal to 20,000 psi after (c).