Abstract:
An improved high pressure apparatus can include a plurality of complementary die segments. The die segments can have inner surfaces which are shaped to form a die chamber upon assembly of the die segments. A pair of anvils can be oriented such that an anvil is at each end of the die chamber. To prevent the die segments from being forced apart during movement of the anvils, force members can be connected to the die segments. The force members can apply discrete forces to the die segments sufficient to retain the die segments in substantially fixed positions relative to each other during application of force by the pair of anvils. Using such a high pressure apparatus can achieve pressures as high as 10 GPa with improved useful die life and larger reaction volumes.
Abstract:
An improved method for synthesizing superabrasive particles provides high quality industrial superabrasive particles with high yield and a narrow size distribution. The synthesis method can include forming a growth precursor of a substantially homogeneous mixture of raw material and catalyst material or layers of raw material and metal catalyst. The growth precursor can have a layer of adhesive over at least a portion thereof. A plurality of crystalline seeds can be placed in a predetermined pattern on the layer of adhesive. The growth precursor can be maintained at a temperature and pressure at which the superabrasive crystal is thermodynamically stable for a time sufficient for a desired degree of growth. Advantageously, the patterned placement of crystalline seeds and disclosed processes allow for production of various morphologies of synthetic diamonds, including octahedral and cubic diamonds, and improved growth conditions generally. As a result, the grown superabrasive particles typically have a high yield of high quality particles and a narrow distribution of particle sizes.
Abstract:
The present invention provides a method of preparation for diamond, graphite or mixtures of diamond and graphite by reduction of CO or CO2. Said method comprises a step of contacting an active metal capable of reducing a carbon source into elementary carbon with carbon source (such as CO and/or CO2 and/or their origin) under conditions suitable to reduce the carbon source to elementary carbon in the course of a reduction reaction. After the raw diamond or mixtures of diamond and graphite thus obtained are subjected to intensive heat treatment with perchloric acid, pure diamond granules are obtained. The present method employs relatively low reaction temperature and pressure and the facilities needed in the method are simple and easy to operate. Diamond finally obtained has good crystallinity and free of impurities with granule size of several hundred micrometer. In addition, the present invention makes use of the industrial by-product of CO and CO2 which not only turns wastes into valuables and is low in cost, but also improves the environment and thus possesses both good social benefits and economical benefits.
Abstract:
Multi-layered superabrasive tools and methods for the making thereof are disclosed and described. In one aspect, superabrasive particles are chemically bonded to a matrix support material according to a predetermined pattern by a braze alloy. The brazing alloy may be provided as a powder, thin sheet, or sheet of amorphous alloy. A template having a plurality of apertures arranged in a predetermined pattern may be used to place the superabrasive particles on a given substrate or matrix support material.
Abstract:
Superabrasive tools and methods for the making thereof are disclosed and described. In one aspect, superabrasive particles are chemically bonded to a matrix support material according to a predetermined pattern by a braze alloy. The brazing alloy may be provided as a powder, thin sheet, or sheet of amorphous alloy. A template having a plurality of apertures arranged in a predetermined pattern may be used to place the superabrasive particles on a given substrate or matrix support material.
Abstract:
An element-doped diamond crystal is disclosed herein. The crystal includes at least one dopant element which has a greater concentration toward or near an outermost surface of the crystal than in the center of the crystal. The concentration of the dopant element is at a local minimum at least about 5 micrometers below the surface. The concentration-profile of the dopant element for these diamond crystals causes an expansion of the diamond lattice, thereby generating tangential compressive stresses at the surface of the diamond crystal. These stresses beneficially increase the compressive fracture strength of the diamond.
Abstract:
Superabrasive tools and methods for the making thereof are disclosed and described. In one aspect, superabrasive particles are chemically bonded to a matrix support material according to a predetermined pattern by a braze alloy. The brazing alloy may be provided as a powder, thin sheet, or sheet of amorphous alloy. A template having a plurality of apertures arranged in a predetermined pattern may be used to place the superabrasive particles on a given substrate or matrix support material.
Abstract:
A colorless and transparent, substantially inclusion-free diamond crystal which can be applied to decorative uses and optical parts is synthesized by a process using a temperature gradient method in an ultra-high pressure apparatus. This process comprises using, as a solvent for the growth of the crystal, at least one metal selected from the group consisting of Fe, Co, Ni, Mn and Cr (at least two metals in the case of containing Fe) and as a nitrogen getter for the removal of nitrogen in the solvent, at least one metal selected from the group consisting of Al, Ti, Zr, Hf, V, Nb and Ta in a proportion of 0.5 to 7% by weight (at most 2% by weight when using only Al) to the solvent metal.
Abstract:
A reaction vessel for use in producing large diamond crystals of good quality and yield includes a reaction volume and a reaction mass located in the volume. The reaction mass comprises a plurality of seed particles located in or on a surface in the reaction volume and a carbon source separated from the seed particles by a mass of metallic catalyst/solvent for diamond synthesis. The mass comprises alternating layers of carbon-rich and carbon-lean metallic catalyst/solvent which lie parallel or substantially parallel to the surface. There is also provided a mass of alternating layers of carbon-rich and carbon-lean metallic catalyst/solvent.
Abstract:
A method of producing diamond crystal growth on a seed crystal is provided. The method includes the steps of providing a seed crystal containing at least one twin plane and re-entrant growth surfaces associated therewith and applying high temperature/high pressure synthesis conditions to the seed crystal to cause diamond growth to occur preferentially on the re-entrant surfaces. The diamond growth on the seed crystal results in a diamond crystal being produced which has an aspect ratio greater than 1.