Provided are a luminescent diamond material and method of producing the same. The method may include the steps of providing a catalyst selected from one or more of the group of cobalt, iron, manganese and nickel; providing an enhancer selected from one or more of the group of boron, germanium, phosphorous, silicon and tin; providing graphite; blending the catalyst, enhancer and graphite to form a homogenized blend; and subjecting the homogenized blend to a high temperature, high pressure process to form a luminescent diamond material having a plurality of diamond particles having a plurality of defect centers, wherein the luminescent diamond material luminesces at a wavelength of about 700 nm to about 950 nm and energy of about 1.77 eV to about 1.30 eV.

Provided is polycrystalline diamond having a diamond single phase as basic composition, in which the polycrystalline diamond includes a plurality of crystal grains and contains boron, hydrogen, oxygen, and the remainder including carbon and trace impurities; the boron is dispersed in the crystal grains at an atomic level, and greater than or equal to 90 atomic % of the boron is present in an isolated substitutional type; hydrogen and oxygen are present in an isolated substitutional type or an interstitial type in the crystal grains; each of the crystal grains has a grain size of less than or equal to 500 nm; and the polycrystalline diamond has a surface covered with a protective film.

A method capable of obtaining pure single phase hexagonal diamond in an industrially usable size (bulk) is provided. Highly oriented and highly crystallized graphite having a mosaic spread of 5 or less is used as a starting material, and is subjected to a temperature ranging from 1000 to 1500 C. at a pressure ranging from 20 to 25 GPa. The size of the bulk sintered body of pure single-phase hexagonal diamond obtained by this method depends on the size of the starting graphite. However, as long as the pressure and temperature can be entirely provided (i.e., as long as the adequate high pressure and temperature are applied to the sample chamber of high pressure apparatus), any desired size can be obtained.

Disclosed herein is an apparatus and method for growing a diamond. The apparatus for growing a diamond comprises: a reaction cell that is configured to grow the diamond therein; a main heater including a main heating surface that is arranged along a first inner surface of the reaction cell; and a sub-heater including a sub-heating surface that is arranged along a second inner surface of the reaction cell, the second inner surface being non-parallel with the first inner surface.

In accordance with the present invention, there is provided a process for producing hydrogen and graphitic carbon from a hydrocarbon gas comprising: contacting at a temperature between 600? C. and 1000? C. the catalyst with the hydrocarbon gas to catalytically convert at least a portion of the hydrocarbon gas to hydrogen and graphitic carbon, wherein the catalyst is a low grade iron oxide.

Nano polycrystalline diamond is composed of carbon, an element of different type which is an element other than carbon and is added to be dispersed in carbon at an atomic level, and an inevitable impurity. The polycrystalline diamond has a crystal grain size not greater than 500 nm. The polycrystalline diamond can be fabricated by subjecting graphite in which the element of different type which is an element other than carbon has been added to be dispersed in carbon at an atomic level to heat treatment within high-pressure press equipment.

A polycrystalline diamond structure comprises a first region and a second region adjacent the first region, the second region being bonded to the first region by intergrowth of diamond grains. The first region comprises a plurality of alternating strata or layers, each or one or more strata or layers in the first region having a thickness in the range of around 5 to 300 microns. The polycrystalline diamond (PCD) structure has a diamond content of at most about 95 percent of the volume of the PCD material, a binder content of at least about 5 percent of the volume of the PCD material, and one or more of the layers or strata in the first region comprise and/or the second region comprises diamond grains having a mean diamond grain contiguity of greater than about 60 percent and a standard deviation of less than about 2.2 percent. There is also disclosed a method of making such a polycrystalline diamond structure.

A method of providing well-shaped diamond grains of at most about 100 microns in size. The method includes providing a synthesis assembly comprising a source of carbon material, a plurality of seed grains on which diamond material can crystallize, and solvent-catalyst material for promoting the crystallization of the diamond grains, and subjecting the synthesis assembly to a condition for growing the diamond grains. The synthesis condition is maintained long enough for at least about half of the carbon material to be converted into the diamond grains.

A capsule assembly for an ultra-high pressure furnace, comprising a containment tube having an interior side surface and defining a central longitudinal axis; a chamber suitable for accommodating a reaction assembly, a proximate and a distal end heater assembly, and a side heater assembly. When assembled, the chamber is contained within the containment tube and arranged longitudinally between the proximate and distal end heater assemblies. The side heater assembly is disposed adjacent the interior side surface and electrically connects the end heater assemblies with each other. Each end heater assembly has a respective peripheral side disposed adjacent the interior side surface Heat is produced in the chamber in response to an electric current flowing through the end and side heater assemblies. At least a proximate side heater barrier spaces apart the side heater assembly from at least the proximate end heater assembly, adjacent its peripheral side, operative to prevent a portion of the side heater assembly from intruding between the peripheral side of the proximate end heater assembly and the containment tube and short-circuiting at least part of the proximate end heater assembly, when the end heater assemblies move towards each other in response to a force applied by the ultra-high pressure furnace onto the capsule assembly along the central longitudinal axis.

A capsule assembly for an ultra-high pressure furnace, comprising a containment tube defining a central longitudinal axis, a chamber suitable for accommodating a reaction assembly, a proximate and a distal end heater assembly, and a side heater assembly. When assembled, the chamber and the side heater assembly are contained within the containment tube and arranged longitudinally between the proximate and distal end heater assemblies. Each end heater assembly comprises a respective conduction volume forming a respective electrical path through the end heat assembly. The side heater assembly electrically connects the respective conducting volumes to each other, and heat is produced in the chamber in response to an electric current flowing through the side heater assembly and the conducting volumes. At least the proximate end heater assembly comprises a first insulation component including an outer insulation volume. The conducting volume of at least the proximate end heater assembly includes an inner conducting volume, and the inner conducting volume is laterally spaced apart from the containment tube by the outer insulation volume.