Abstract: A production method is provided that enables to produce a large-sized bulk silicon carbide (SiC) crystal of high quality at low cost. A large-sized bulk silicon carbide (SiC) crystal of high quality can be obtained at a lower temperature by reacting silicon (Si) and carbon (C) produced from a lithium carbide such as dilithium acetylide (Li2C2) with each other in an alkali metal melt and thereby producing or growing a silicon carbide (SiC) crystal. FIG. 17 shows a high-resolution TEM (HR-TEM) image of the resultant 2H—SiC crystal. A preferable lithium carbide is dilithium acetylide (Li2C2). A preferable alkali metal melt is a melt of lithium alone.

Abstract: A raw material mixture containing an easily oxidizable material is weighed. The raw material mixture is melted and then solidified within a reaction vessel 1 set in a non-oxidizing atmosphere to thereby produce a solidified matter 19. The reaction vessel 1 and the solidified matter 19 are heated in a non-oxidizing atmosphere within a crystal growth apparatus to melt the solidified matter to thereby produce a solution. A single crystal is grown from the solution.

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 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 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: 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.

Abstract: A method for temporarily securing superabrasive particles to a substrate such as a tool substrate or a growth precursor and articles formed therefrom are provided. The method can include applying an array of adhesive droplets onto at least a portion of a substrate in accordance with a predetermined pattern. The pattern may be uniform grid equally spacing each adhesive droplet. The adhesive droplets can be suitable to each secure only a single superabrasive particle. The method may further include adhering a single superabrasive particle to each adhesive droplet. As a result of the method can yield a tool substrate and grow precursor having enhance particle growth and wear properties.

Abstract: An improved method for controlling nucleation sites during superabrasive particle synthesis can provide high quality industrial superabrasive particles with high yield and a narrow size distribution. The synthesis method can include forming a raw material layer, forming a particulate catalyst layer adjacent the raw material layer, and placing crystalline seeds in a predetermined pattern at least partially in the catalyst layer or raw material layer to form a growth precursor. Alternatively, the raw material and catalyst material can be mixed to form a particulate crystal growth layer and then placing the crystalline seeds in a predetermined pattern in the growth layer. Preferably, seeds can be substantially surrounded by catalyst material. 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.

Abstract: High pressure synthesis of various crystals such as diamond, cBN and the like can be carried out using reaction assemblies suitable for use in methods such as temperature gradient methods. The reaction assembly can be oriented substantially perpendicular to gravity during application of high pressure. Orienting the reaction assembly in this manner can avoid detrimental effects of gravity on the molten catalyst, e.g., convection, hence increasing available volumes for growing high quality crystals. Multiple reaction assemblies can be oriented in series or parallel, each reaction assembly having one or more growth cells suitable for growth of high quality crystals. Additionally, various high pressure apparatuses can be used. A split die design allows for particularly effective results and control of temperature and growth conditions for individual crystals.

Abstract: A method of producing a nitride single crystal includes the step of forming a material transport medium layer containing a compound of rare earth element on a surface of a nitride crystal, and the step of making a seed crystal in contact with the material transport medium layer to grow a nitride single crystal on the seed crystal. The material transport medium layer contains the compound of rare earth element and at least one compound selected from a group of aluminum compound, alkaline earth compound and transition metal compound. With this producing method, a large nitride single crystal having a crystal size of at least 10 mm is obtained.

Abstract: The present invention provides a manufacturing method in which high quality GaN crystals and GaN crystal substrates can be manufactured under mild conditions of low pressure and low temperature. In a method of manufacturing GaN crystals in which in a gas atmosphere containing nitrogen, gallium and the nitrogen are allowed to react with each other to generate GaN crystals in a mixed melt of the gallium and sodium, the gallium and the nitrogen are allowed to react with each other under a pressurizing condition that exceeds atmospheric pressure, and pressure P1 (atm(×1.013×105 Pa)) of the pressurizing condition is set so as to satisfy the condition that is expressed by the following conditional expression (I): P?P1<(P+45),??(I) where in the expression (I), P (atm(×1.013×105 Pa)) denotes the minimum pressure that is required for generating GaN crystals at a temperature T° C. of the mixed melt.

Abstract: In a crystal preparing device, a crucible holds a mixed molten metal containing alkali metal and group III metal. A container has a container space contacting the mixed molten metal and holds a molten alkali metal between the container space and an outside of the container, the molten alkali metal contacting the container space. A gas supply device supplies nitrogen gas to the container space. A heating device heats the crucible to a crystal growth temperature. The crystal preparing device is provided so that a vapor pressure of the alkali metal which evaporates from the molten alkali metal is substantially equal to a vapor pressure of the alkali metal which evaporates from the mixed molten metal.

Abstract: In a diamond manufacturing method, a melt of carbon and blue kimberlite is contained in a vessel at 1000° C. The vessel is pressurized by a gas of predominantly hydrogen to 200 atmospheres. A crystallization seed is drawn from the melt to generate a piece of diamond material.

Abstract: ?-ZrNCl polycrystalline powder prepared by chemical transport method and NH4Cl are mixed in a molar ratio of 1:2. The mixture is encapsulated in a Au capsule (6 mm in inner diameter and 6 mm in depth) of a reaction vessel 2, which is then enclosed in a highly heat-conductivitive sodium chloride block as an electrically insulating pressure medium 6. The mixture held in the sodium chloride block is placed in a carbon tube 8 for serving as a heater. In a cubic-pressing apparatus using a pyrophyllite 12 as a pressure-transmitting medium, the mixture is heated at 900° C. for 2 hours under an applied pressure of 3 GPa. After the mixture is allowed to stand until it is cooled down to room temperature, the Au capsule is taken out and light green ?-ZrNCl single crystals are obtained. A large single crystal among them had a hexagonal plate-like habit and is transparent with dimensions about 2 mm in diameter, and 0.3 mm in thickness.

Abstract: A process for growing by chemical vapor deposition a heteroepitaxial single crystal diamond is disclosed. The process provides a substrate which enables the growth of single crystal diamond which is vapor coated on an iridium film. An intermediate process for producing a composite composition with diamond nuclei is also described. Further described are composite compositions of metal oxide, iridium and single crystal diamond films or diamond nuclei. Single crystal diamond is useful in a variety of electronics and acoustics fields.

Abstract: The invention has as an object proving a carbon nanomaterial fabrication method that can continuously mass-produce a high purity carbon a nanomaterial. The tube-shaped or fiber-shaped carbon nanomaterial having carbon as the main constituent is fabricated with a compound that includes carbon (raw material) and an additive that includes a metal by using a fluidized bed reactor.

Abstract: A very-high pressure generator of construction such that the lower and upper guide blocks of the generator are each configured so as to form a pyramidal recess on the bottom surface and an upside-down pyramidal recess on the top surface accurately symmetrically, their pyramidal slopes given one and the same angle of inclination and are prevented from being deformed under high pressure not by enlarging the guide blocks and the press, but by making the support conditions of all the anvils of the generator uniform, the positions of the anvils can easily be adjusted and therefore the generator is capable of pressurizing a pressure transmitting medium into the shape of the desired cube accurately. Each of the lower and upper guide blocks has a pyramidal recess in its bottom surface and an upside-down pyramided recess in its top surface and us symmetric with respect to its horizontal center plane. Each of lower and upper base blocks has a lower upside-down pyramidal portion and an upper pyramidal portion.

Abstract: The invention provides a mass of crystals, particularly diamond crystals, having a size of less than 100 microns and in which mass the majority of the crystals are faceted single crystals. The invention further provides a method of producing such a mass of crystals which utilizes crystal growth under elevated temperature and pressure conditions, the supersaturation driving force necessary for crystal growth being dependent, at least in part, on the difference in surface free energy between low Miller index surfaces and high Miller index surfaces of the crystals. Preferably, the method is carried out under conditions where the Wulff effect dominates.

Abstract: A method of making a bonded, coherent material comprising a mass of crystals, preferably diamond crystals, in a matrix is provided. The steps include providing a source of the crystals of the type to be grown and which are substantially free of macroscopically faceted surfaces, producing a reaction mass by bringing the source crystals into contact with a suitable solvent/catalyst, subjecting the reaction mass to conditions of elevated temperature and pressure suitable for crystal growth in the reaction zone of a high temperature/high pressure apparatus to produce the material and removing the material from the reaction zone, the conditions of crystal growth being chosen such that the source crystals are converted to crystals having developed macroscopic facets of low Miller index. Preferably the conditions of elevated temperature and pressure used are such that the Wulff effect dominates.

Abstract: A method for improving the toughness of a CBN product made by a high temperature/high pressure (HP/HT) process commences by forming a blend of an oxygen getter and CBN product-forming feedstock. The blend is subjected to a CBN high temperature/high pressure (HP/HT) process for forming a CBN product. The amount of oxygen getter in the blend is sufficient to improve the toughness of the CBN product. The resulting CBN product desirably has an oxygen content of less than about 300 ppm. Oxygen getters include Al, Si, and Ti. The HP/HT process is conducted in the absence or presence of catalytic materials.

Abstract: A low free energy method for more rapidly diffusing an impurity as exemplified by boron, into a natural or synthetic diamond or other crystalline element in powdered or granular form, without degradation of the crystalline structure. The present method includes the steps of providing a mixture of the diamond or other crystalline element and the impurity in a solid phase; treating the mixture to bring the impurity into conforming contact with the outer surface of the crystalline element; and heating the mixture to a temperature between about 200° C. and about 2000° C. As an example, a diamond is disclosed having boron as an impurity diffused into the crystalline structure thereof by the present method, at a ratio of from about 0.1 part of the impurity per 1 million parts of the diamond to about 600 parts of the impurity per 1 million parts of the diamond.

Abstract: An apparatus for purifying metallurgical grade silicon to produce solar grade silicon has a container for holding molten silicon and one or more torches for providing oxygen and hydrogen gas to heat the molten silicon so that the reaction time is prolonged, to create turbulence, and to introduce silica powder and water vapor for reactions with molten silicon. The molten silicon is then directionally solidified.

Abstract: A method of making a bonded, coherent material comprising a mass of diamond crystals in a matrix, which optionally contains another phase. The method includes the steps of providing a source of diamond crystals, providing a plurality of diamond centers defined by diamond crystals, producing a reaction mass by bringing the source and growth centers into contact with a solvent/catalyst, subjecting the reaction mass to conditions of elevated temperature and pressure suitable for crystal growth in the reaction zone of a high temperature/high pressure apparatus to produce the material, and removing the material from the reaction zone. The method is characterized by providing the necessary supersaturation of carbon in the solvent/catalyst, at least in part and preferably predominantly, by a selection of particle size difference between the source crystal and the growth centers. The mass of diamond crystals in the matrix of the bonded, coherent material of the invention has a high concentration of twinned diamonds.

Abstract: The present invention describes a novel abrasive tool that contains abrasive particles distributed in a predetermined pattern. Such a pattern is produced by fabricating two-dimensional slices and subsequently assembling and consolidating them into a three-dimensional tool. Abrasive particles 20 may be incorporated during the process of making these two-dimensional slices, or they may be planted afterwards into these slices 100 that contains matrix powder. In the latter case, the planting may be guided by a template 110 with apertures 114 laid in a specific pattern.

Abstract: A germanium layer 19 is melted on top of a starting polycrystalline silicon ingot 18, at a temperature below the melting point of pure silicon. Silicon is dissolved at the interface and floats to the top of the germanium melt to form a silicon melt layer 11, from which a crystal 20 can be drawn. The process permits the production of large diameter crystal with low oxygen content and no more than one percent germanium.

Abstract: An apparatus for purifying metallurgical grade silicon to produce solar grade silicon has a container for holding molten silicon and one or more submergible torches for providing a flame surrounded by inert gas to heat the molten silicon so that the reaction time is prolonged, to create turbulence, and to introduce silica powder and water vapor for reactions with molten silicon. The molten silicon is then directionally solidified by providing the container in a coolant tank and controlling the coolant level with controllable valves so that further purification is achieved by segregating impurities.

Abstract: A method for producing cubic SiC monocrystals includes dissolving SiC powder or other starting material in a solvent at high overpressures and growing the monocrystals on a seed crystal.

Abstract: A process for preparing an oxide crystal by means of solution growth in the presence of a solvent is provided. The solvent includes a mixture of an oxide containing at least one member of those elements which constitute the oxide crystal, a halide containing at least one member of those elements which constitute the oxide crystal, and metallic silver.

Abstract: Articles with a tenaciously adherent diamond coating are made by forming a diamond coating on a base material by vapor-phase synthesis without causing any warpage of the coating. The diamond coating layer is formed on the surface of a base material having a number of pores formed by electric discharge or laser beams and having a depth of 0.0001-0.2 mm and a diameter of 0.001-0.02 mm. The pores may be connected to one another to form a groove. Suitable examples of the base material include molybdenum, tungsten, silicon, tungsten carbide, silicon carbide, silicon nitride, and cemented carbide mainly comprising tungsten carbide and cobalt and/or nickel.

Abstract: A colorless, transparent low defect density, synthetic type IIa diamond single crystal, in which the etch pits due to needle-shaped defects are at most 3.times.10.sup.5 pieces/cm.sup.2, and which can be applied to uses needing high crystallinity of diamond, for example, monochromators, semiconductor substrates, spectroscopic crystals in X-ray range, electronic materials, etc., is provided by a process for the production of the colorless, transparent low defect density, synthetic diamond single crystal by growing new diamond crystal on a seed crystal of diamond by the temperature gradient method which comprises using a crystal defect-free diamond single crystal, as a seed crystal of diamond, and optionally subjecting to a heat treatment in a non-oxidizing atmosphere at a low pressure and a temperature of 1100 to 1600.degree. C.

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.

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.

Abstract: An improved plasma enhanced chemical vapor deposition (CVD) reactor is provided for the synthesis of diamond and other high temperature materials such as boron nitride, boron carbide and ceramics containing oxides, nitrides, carbides and borides, or the like. An aspect of the present method enables a plasma to substrate distance to be optimized for a given surface. This has been found to enable a substantially uniform thin film coating of diamond or like material to be deposited over a substrate.

Abstract: A method of making n-type semiconducting diamond is disclosed, which is doped with boron-10 at the time of diamond formation and bombarded with neutrons for in-situ conversion of boron-10 to lithium-7, while filtering the neutrons from high energy components during irradiation.

Abstract: Human-made diamond, as well as naturally found diamond, is a transparent, superhard, crystalline, and electrically nonconductive form of carbon. In this invention, an electrical current of supercritical density alone produces the transformation of graphite to diamond. The entire graphite-to-diamond transformation requires only a few millionths of a second. Using the principles of the invention, diamond can be produced in a variety of shapes, such as loose debris, rods, fibers, bars, dust, etc. In addition to diamond, Buckminster Fuller Balls, known also as C-60 carbon fullerines, are produced using the process and apparatus of the invention.

Abstract: A method produces a columnar, quasi-oriented diamond that exhibits the enhanced optical, thermal and mechanical properties of gem diamonds. This method allows diamond growth rates that are faster than those possible with high pressure diamond growth from a single diamond seed. The columnar, quasi-oriented diamond contains lower grain boundary density than chemically vapor deposited diamond.

Abstract: A method of growing a large single crystalline diamond film, in which a nickel substrate is disposed within a diamond growth chamber. After air has been evacuated from the chamber and the substrate has been heated to a temperature exceeding 1145 Celsius, atomic hydrogen is continuously generated from hydrogen gas supplied to the chamber and accelerated toward the substrate, implanting hydrogen atoms in the top substrate surface and converting it to a liquid film of nickel hydride. Then one of two layers of diamond particles of two to three nanometer cross section is deposited on the liquid nickel hydride film, whereby the diamond particles arrange themselves on the liquid nickel hydride film to their lowest free energy state, forming a nascent contiguous single-crystalline diamond film. Thereafter diamond is homoepitaxially grown on the nascent contiguous single-crystalline diamond film to the desired thickness.

Abstract: A method of epitaxially growing a surface layer on a substrate including the steps of coating the substrate surface, with a meltable film, melting the film and implanting ions into he melted film, to deposit ion material onto the coated substrate surface.

Abstract: A method of synthesizing single diamond crystals using a carbon source containing at least 99.9 atomic % carbon-12. This is accomplished by graphitizing carbon-12 to form a highly crystalline material which can be used as a carbon source in an ultra high pressure creating apparatus to produce single diamond crystals by means of a temperature difference process.

Abstract: A method of coating a material surface with thin film silicon comprises dissolving silicon in a metal solvent to form a solution and subsequently deposited the dissolved silicon from the solution by controlling the temperature of the solution and thereby depositing a layer of silicon onto the material surface. The metal solvent is preferably a mixture of gold and a metal or metals which either have a melting point below the deposition temperature range or which form a eutectic with gold and have a eutectic temperature below the deposition temperature range. The temperature of the solution is controlled so that the silicon becomes super saturated in the solution and is deposited out of solution onto the material surface.

Abstract: Single-crystal diamond consisting of isotopically pure carbon-12 or carbon-13 has been found to have a thermal conductivity higher than that of any substance previously known, typically at least 40% higher than that of naturally occurring IIA diamond. It may be prepared by a method comprising an initial step of low pressure chemical vapor deposition employing an isotopically pure hydrocarbon in combination with hydrogen, followed by comminution of the diamond thus obtained and conversion thereof to single-crystal diamond under high pressure conditions.