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.

An electrode comprising synthetic high-pressure high-temperature diamond material, the diamond material comprising a substitutional boron concentration of between 1×10.sup.20 and 5×10.sup.21 atoms/cm.sup.3 and a nitrogen concentration of no more than 10.sup.19 atoms/cm.sup.3. The electrode has a ΔE.sub.3/4-1/4 as measured with respect to a saturated calomel reference electrode in an aqueous solution containing 0.1 M KNO.sub.3 and 1 mM of Ru(NH.sub.3).sub.6.sup.3+ selected any of less than 70 mV, less than 68 mV, less than 66 mV, and less than 64 mV, and/or a peak to peak separation ΔE.sub.p as measured with respect to a saturated calomel reference electrode in an aqueous solution containing 0.1 M KNO.sub.3 and 1 mM of Ru(NH.sub.3).sub.6.sup.3+ selected any of less than 70 mV, less than 68 mV, less than 66 mV, and less than 64 mV.

A method of making molecularly doped nanodiamond. A versatile method for doping diamond by adding dopants into a carbon precursor and producing diamond at high pressure, high temperature conditions. Molecularly doped nanodiamonds that have direct incorporation of dopants and therefore without the need for ion implantation. Molecularly-doped diamonds that have fewer lattice defects than those made with ion implantation.

Methods and apparatuses for making nanomaterials are disclosed. The methods involve passing one or more source materials through a high pressure and high temperature chamber with an open throat, and then allowing the reactants to expand into a lower pressure, lower temperature zone. The source material is non-stoichiometric and fuel-rich so that excess un-combusted primary source material can form the nanomaterials. In some cases, the apparatus may be in the form of a modified rocket engine. The methods may be used to make various materials including: carbon nanotubes, boron nitride nanomaterials, titanium dioxide, and any materials that are currently produced by flame synthesis, including but not limited to electrocatalysts. The methods may also be used to make nanomaterials outside the Earth's atmosphere. The methods can include making, coating, or repairing structures in space, such as antennae.

An apparatus for the manufacture of cubic Boron Nitride includes a pressure vessel having a chamber therein, and a body located in the chamber. The pressure vessel and the body are formed of materials having different coefficients of expansion. The coefficient of expansion of the body is greater than the coefficient of expansion of the pressure vessel. The pressure vessel is formed from a material having a melting point in excess of 1327° C. and capable of withstanding a pressure of at least 4.4Gpa at a temperature of at least 1327° C. The chamber is configured to receive the body, and a Boron Nitride source, the apparatus further comprising a furnace configured to heat at least the body to a temperature at least of 1327° C. The coefficient of expansion of the body is selected such that upon heating thereof to at least 1327° C. the pressure exerted on the Boron Nitride source is at least 4.4Gpa.

Polycrystalline diamond constructions are formed from a mixture of diamond grains including a first volume of fine-sized diamond grains, and a second volume of coarse-sized diamond grains. The fine-sized diamond grains are partially graphitized, and the coarse-sized diamond grains are not graphitized. The mixture of diamond grains is subjected to high pressure/high temperature sintering process conditions in the presence of a sintering aid thereby forming polycrystalline diamond. Contact areas between coarse-sized diamond grains in the polycrystalline diamond construction are substantially free of graphite.

Embodiments relate to polycrystalline diamond compacts (“PDCs”) including a polycrystalline diamond (“PCD”) table having a diamond grain size distribution selected for improving performance and/or leachability. In an embodiment, a PDC includes a PCD table bonded to a substrate. The PCD table includes a plurality of diamond grains exhibiting diamond-to-diamond bonding therebetween. Other embodiments are directed to methods of forming PDCs, and various applications for such PDCs in rotary drill bits, bearing apparatuses, and wire-drawing dies.

A diamond polycrystal includes diamond grains, the diamond polycrystal including a cubic diamond and a 6H type hexagonal diamond, wherein the cubic diamond and the 6H type hexagonal diamond exist in the same or different diamond grains, and a ratio Ab.sub.1/Ab.sub.2 is more than or equal to 0.4 and less than or equal to 1, Ab.sub.1 representing a maximum value of absorption in a range of more than or equal to 1200 cm.sup.−1 and less than or equal to 1300 cm.sup.−1 in an infrared absorption spectrum, Ab.sub.2 representing a maximum value of absorption in a range of more than or equal to 1900 cm.sup.−1 and less than or equal to 2100 cm.sup.−1.

In a diamond polycrystal, a value of a ratio (a′/a) of a′ to a is less than or equal to 0.99 in a Knoop hardness test performed under a condition defined in JIS Z 2251:2009, where the a represents a length of a longer diagonal line of a first Knoop indentation formed in a surface of the diamond polycrystal when a Knoop indenter with a test load of 4.9 N is pressed onto the surface of the diamond polycrystal, and the a′ represents a length of a longer diagonal line of a second Knoop indentation remaining in the surface of the diamond polycrystal after releasing the test load.

Embodiments relate to polycrystalline diamond compacts (“PDCs”) including a polycrystalline diamond (“PCD”) table having a diamond grain size distribution selected for improving performance and/or leachability. In an embodiment, a PDC includes a PCD table bonded to a substrate. The PCD table includes a plurality of diamond grains exhibiting diamond-to-diamond bonding therebetween. The plurality of diamond grains includes a first amount being about 5 weight % to about 65 weight % of the plurality of diamond grains and a second amount being about 18 weight % to about 95 weight % of the plurality of diamond grains. The first amount exhibits a first average grain size of about 0.5 μm to about 30 μm. The second amount exhibits a second average grain size that is greater than the first average grain size and is about 10 μm to about 65 μm. Other embodiments are directed to methods of forming PDCs, and various applications for such PDCs in rotary drill bits, bearing apparatuses, and wire-drawing dies.