Abstract:
A method for changing the color of colored Type I natural diamonds includes placing a Type I natural diamond into a high pressure/high temperature (HP/HT) press at elevated pressure and elevated temperature for a time sufficient to change or improve the color of the diamond.
Abstract:
An improved method for synthesizing superabrasive particles provides high quality industrial superabrasive I-,articles with high yield and a narrow size distribution. The synthesis method includes forming a substantially homogeneous mixture of raw material and catalyst material or layers of raw material and metal catalyst. A plurality of crystalline seeds is placed in a predetermined pattern in the mixture or one of the layers to form a growth precursor. The growth precursor is 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 synthetic octahedral 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:
A jadeite material has a thickness in excess of about 1.0 mm and CIELAB indices of L*>42, a* +6. The grain size of the jadeite material is less than about 30 microns and is an equiaxed grain structure. The jadeite material has an optical transmission peak between 500 and 565 nm with an I/IO optical transmission ratio of over 40%. The first step in making the jadeite material is to wrap a glass block, convertible by HP/HT into jadeite and having a nominal composition of NaAlSi2O6, with a graphite or refractive metal sheet. The wrapped glass block is placed in an HP/HT apparatus, rapidly heated, and subjected therein to a pressure in excess of about 3 GPa and a temperature in excess of about 1000° C. for a time adequate to convert the glass block into jadeite. The jadeite material then is cooled and the pressure subsequently released.
Abstract:
The present invention deals with the generation of sharp single crystal diamond tips and the arrays of these tips, and their fabrication technology. The invention combines the deposition of synthetic diamond films with reactive etching processes. Upon the diamond orientation prepared and reactive etching environment with considerable directivity of ions, single crystal diamond tips with different apical angles can be fabricated. Very sharp diamond tips with an apical angle of no more than about 28° and a tip radius smaller than 50 nm are fabricated on pyramidal-shaped [001]-textured diamond films by subsequent reactive etching., The technology is based on selective etching of sp2- and sp3- hybridized carbons by the activated constituents of an etching environment, in particular based on atomic hydrogen, in a way similar to ion bombardment, which contributes to overall etching and local conversion of diamond to graphitic phase promoting further etching with chemically activated species. This novel method is capable of forming diamond tip arrays over large areas with great uniformity and high reproducibility. The diamond tips prepared are single diamond crystals with their [001] axes parallel each other and normal to the substrate surface. The invented technology enables the control of the apical angle, radius and density of the diamond tips.
Abstract:
A process for producing single-crystal gallium nitride comprising the steps of performing congruent melting of gallium nitride at a high pressure between 6×104 atm. and 10×104 atm. and at a high temperature between 2,200° C. and 2,500° C. and then slowly cooling the obtained gallium nitride melt at the stated high pressure.
Abstract:
Polishing particles are made of artificial diamond produced by a shock method, having density of 3.0-3.35 g/cm3 and including secondary particles with average particle diameter of 30 nm-500 nm. Such polishing particles are produced by firstly obtaining a product containing artificial diamond by a shock method, then subjecting this product to an acid treatment by using one or more strong acids such as concentrated sulfuric acid, concentrated nitric acid and concentrated hydrochloric acid to thereby remove impurities from and wash the product, thereafter subjecting the product to a classification process to thereby separate artificial diamond of a first kind having secondary particles with particle diameters of 30 nm-500 nm and artificial diamond of a second kind having secondary particles with particle diameters in excess of 500 nm and selecting artificial diamond of a third kind having density of 3.0-3.35 g/cm3 out of the artificial diamond of the first kind. It is the artificial diamond of the third kind that is to be used as the diamond polishing particles.
Abstract translation:抛光颗粒由人造金刚石制造,其通过冲击法制备,密度为3.0-3.35g / cm 3,并且包括平均粒径为30nm-500nm的二次颗粒。 通过首先通过冲击法获得含有人造金刚石的产品,然后通过使用一种或多种强酸例如浓硫酸,浓硝酸和浓盐酸对该产物进行酸处理,从而除去杂质, 然后对产品进行洗涤,然后对产品进行分级处理,从而分离具有粒径为30nm-500nm的二次粒子的第一种人造金刚石和具有粒径超过二次粒子的第二种人造金刚石 并选择第三类人造金刚石,其中第三种人造金刚石具有3.0-3.35g / cm 3的密度,出自第一类人造金刚石。 是用作金刚石抛光颗粒的第三种人造金刚石。
Abstract:
A method for producing a semiconductor diamond containing boron by the high pressure synthesis method, wherein a graphite material to be converted to the semiconductor diamond is mixed with boron or a boron compound, formed and fired, in such a way that the resultant graphite material contains a boron component uniformly dispersed therein and has an enhanced bulk density, a high purity and a reduced content of hydrogen.
Abstract:
This invention presents a high-pressure high-temperature reaction vessel having a metallized graphite heater for improved performance. The metallized heater consists of a graphite tube comprising a refractory metal. Metallization of the graphite heater is accomplished either by coating the graphite tube with a refractory metal, by intermixing a refractory metal in the graphite, or by positioning a refractory metal sheet or cylinder adjacent the graphite heater. The refractory metal constrains the graphite heater, adds toughness to the heater, shields the heater from outside contamination, and provides an electrical contact for a thermocouple.
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:
Processes are disclosed for performing non-microwave, non-arcjet plasma-assisted chemical vapor deposition of diamond in which substantially no particles impact the growing diamond surface with energies sufficient to prevent the growth of diamond. The energies of the particles are limited by selecting frequency, pressure, magnetic fields, electrical bias, or a combination thereof to the deposition region of the chamber. Diamond materials formed by these processes are also disclosed.