Single-crystal diamond is composed of carbon in which a concentration of a carbon isotope .sup.12C is not lower than 99.9 mass % and a plurality of inevitable impurities other than carbon. The inevitable impurities include nitrogen, boron, hydrogen, and nickel, and a total content of nitrogen, boron, and hydrogen of the plurality of inevitable impurities is not higher than 0.01 mass %. In order to manufacture single-crystal diamond, initially, a hydrocarbon gas in which a concentration of the carbon isotope .sup.12C is not lower than 99.9 mass % is subjected to denitrification.

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.

A measurement tool having a tip part consisting of polycrystalline diamond, in which the polycrystalline diamond contains at least one of dispersed nitrogen, boron, and phosphorus, the tool includes a shank part, and the tip part is provided at an end portion of the shank part.

A super hard polycrystalline construction is disclosed as comprising a body of super hard material having a first fraction of super hard grains in a matrix of a second fraction of super hard grains. The average grain size of the first fraction is between around 1.5 to around 10 times the average grain size of the second fraction and the first fraction comprises around 5 vol % to around 30 vol % of the grains of super hard material in the body.

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.

In an embodiment, a polycrystalline diamond table includes a plurality of bonded diamond grains and a plurality of interstitial regions defined by the plurality of bonded diamond grains. The polycrystalline diamond table may be at least partially leached such that at least a portion of at least one interstitial constituent has been removed from at least a portion of the plurality of interstitial regions by exposure to a leaching agent. The leaching agent may include a mixture having a ratio of weight % hydrofluoric acid to weight % nitric acid of about 1.0 to about 2.4, and water in a concentration of about 50 weight % to about 85 weight %. Various other materials, articles, and methods are also disclosed.

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.

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.

In an embodiment, a polycrystalline diamond table includes a plurality of bonded diamond grains and a plurality of interstitial regions defined by the plurality of bonded diamond grains. The polycrystalline diamond table may be at least partially leached such that at least a portion of at least one interstitial constituent has been removed from at least a portion of the plurality of interstitial regions by exposure to a leaching agent. The leaching agent may include a mixture having a ratio of weight % hydrofluoric acid to weight % nitric acid of about 1.0 to about 2.4, and water in a concentration of about 50 weight % to about 85 weight %. Various other materials, articles, and methods are also disclosed.

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.