A polycrystalline diamond and a polycrystalline diamond compact comprise nanostructured polycrystalline diamond particles (aggregates) and binder material. The nanostructured polycrystalline diamond particles (aggregates) are from starting raw materials of nanostructured polycrystalline diamond particles (aggregates) with a size of between 1 m-40 m. The polycrystalline diamond and the polycrystalline diamond compact may comprise micrometer-sized monocrystalline diamond particles. The binder material in the polycrystalline diamond or the polycrystalline diamond compact may be removed partially or completely by a leaching process. The method of making the polycrystalline diamond or the polycrystalline diamond compact comprises sintering diamond particles comprising the nanostructured polycrystalline diamond particles (aggregates) with a size of between 1 m-40 m under high temperature and high pressure in the presence of the binder material.

An apparatus for the manufacture of synthetic diamonds 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 4.4 Gpa at a temperature of at least 1327 C. The chamber is configured to receive the body, and a carbon source, the apparatus further comprising a heating means 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 carbon source is at least 4.4 Gpa.

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.

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.

A synthetic single crystal diamond contains nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less, and the nitrogen atoms do not include any isolated substitutional nitrogen atom.

Provided is a synthetic single crystal diamond containing nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less. The Raman shift (cm.sup.1) of a peak in a primary Raman scattering spectrum of the synthetic single crystal diamond and the Raman shift (cm.sup.1) of a peak in a primary Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a content of 1 ppm or less satisfy the following expression (1):

0.10(1).

A device (1) for generating high pressures in solid and liquid media is described. The device (1) includes a lower shell-shaped body half (2) and an upper shell-shaped body half (3). The device (1) further includes a lower elastic membrane (6) and an upper elastic membrane (7), which are each inserted into the lower body half (2) and into the upper body half (3), respectively. The respective body half (2, 3) and the respective membrane (6, 7) inserted into it each surround a pressure chamber (62, 73). The device (1) furthermore includes an opening and a channel (14) in the lower body half (2), in order to attach an oil line from an oil pump to the device and to pump the oil into the pressure chamber between the lower body half (2) and the elastic membrane (6) inserted into it. The pressure chambers (62, 73) in the lower body half (2) and in the upper body half (3) communicate by means of a line. The device (1) is distinguished in that the line connects the pressure chambers (62, 73) in the lower body half (2) and the upper body half (3) permanently with one another in both the open and the closed state of the device. The device is furthermore distinguished in that it includes a pipeline, which is embodied in the form of a helical spring line (17) and extends outside the lower shell-shaped body half (2) and the upper shell-shaped body half (3).

The present invention relates to a polycrystalline diamond and a polycrystalline diamond compact comprising a continuous network of interbonded diamond constituents comprising nanostructured polycrystalline diamond particles and catalyst material located at the interstitial space among the diamond constituents, and method of making the same. The nanostructured polycrystalline diamond particles are from starting raw materials of Carbonado-type nanostructured polycrystalline diamond particles with a size of between 1 m-40 m. The diamond constituents may comprise micrometer-scale monocrystalline diamond particles. The catalyst material in the polycrystalline diamond or the polycrystalline diamond compact may be removed partially or completely by a leaching process. The method of making the polycrystalline diamond or the polycrystalline diamond compact comprises sintering diamond particles comprising the Carbonado-type nanostructured polycrystalline diamond particles with a size of between 1 m-40 m under high temperature and high pressure in the presence of the catalyst material.

A composite polycrystal includes: a polycrystalline diamond phase including a plurality of diamond particles; and non-diamond phases composed of non-diamond carbon. The non-diamond phases are distributed in the polycrystalline diamond phase. An average value of projected area equivalent circle diameters of the non-diamond phases is not more than 1000 nm.

A polycrystalline diamond construction comprising a body of polycrystalline diamond material formed of a mass of diamond grains exhibiting inter-granular bonding, wherein between around 50 wt % to around 99 wt % of the diamond grains in a cross-section of the body of polycrystalline diamond material taken at any orientation have a sectorial growth structure. A method of making the polycrystalline diamond construction is also disclosed.