A diamond sintered material includes diamond grains, wherein a content ratio of the diamond grains is more than or equal to 80 volume % and less than or equal to 99 volume % with respect to the diamond sintered material, an average grain size of the diamond grains is more than or equal to 0.1 μm and less than or equal to 50 μm, and a dislocation density of the diamond grains is more than or equal to 1.2×10.sup.16 m.sup.−2 and less than or equal to 5.4×10.sup.19 m.sup.−2.

Disclosed is a method for separating nanodiamond clusters synthesized by a detonation method having a size of 100 nm˜1,000 nm into nanodiamonds of 100 nm or less—more specifically, into uniformly sized nanodiamonds in the range of 5 nm˜50 nm, free of metal and alkaline impurities and ready to quantitatively attach functional groups on the surface of the nanodiamonds for applications such as thin film precursor materials, drug delivery systems and cosmetics compositions.

Disclosed is a method for separating nanodiamond clusters synthesized by a detonation method having a size of 100 nm˜1,000 nm into nanodiamonds of 100 nm or less—more specifically, into uniformly sized nanodiamonds in the range of 5 nm˜50 nm, free of metal and alkaline impurities and ready to quantitatively attach functional groups on the surface of the nanodiamonds for applications such as thin film precursor materials, drug delivery systems and cosmetics compositions.

The present disclosure relates to a method of making fancy orange synthetic CVD diamond material. Among other things, the method may involve (i) providing a single crystal diamond material that has been grown by CVD and has a [N.sub.s.sup.0] concentration less than 5 ppm; (ii) irradiating the provided CVD diamond material so as to introduce isolated vacancies V into at least part of the provided CVD diamond material such that the total concentration of isolated vacancies [V.sub.T] in the irradiated diamond material is at least the greater of (a) 0.5 ppm and (b) 50% higher than the [N.sub.s.sup.0] concentration in ppm in the provided diamond material; and (iii) annealing the irradiated diamond material to forming vacancy chains from at least some of the introduced isolated vacancies.

The present disclosure relates to a method of making fancy orange synthetic CVD diamond material. Among other things, the method may involve (i) providing a single crystal diamond material that has been grown by CVD and has a [N.sub.s.sup.0] concentration less than 5 ppm; (ii) irradiating the provided CVD diamond material so as to introduce isolated vacancies V into at least part of the provided CVD diamond material such that the total concentration of isolated vacancies [V.sub.T] in the irradiated diamond material is at least the greater of (a) 0.5 ppm and (b) 50% higher than the [N.sub.s.sup.0] concentration in ppm in the provided diamond material; and (iii) annealing the irradiated diamond material to forming vacancy chains from at least some of the introduced isolated vacancies.

A method of modifying surfaces of diamond particles comprises forming spinodal alloy coatings over discrete diamond particles, thermally treating the spinodal alloy coatings to form modified coatings each independently exhibiting a reactive metal phase and a substantially non-reactive metal phase, and etching surfaces of the discrete diamond particles with at least one reactive metal of the reactive metal phase of the modified coatings. Diamond particles and earth-boring tools are also described.

A method of modifying surfaces of diamond particles comprises forming spinodal alloy coatings over discrete diamond particles, thermally treating the spinodal alloy coatings to form modified coatings each independently exhibiting a reactive metal phase and a substantially non-reactive metal phase, and etching surfaces of the discrete diamond particles with at least one reactive metal of the reactive metal phase of the modified coatings. Diamond particles and earth-boring tools are also described.

Methods of forming composite particles include forming a source material over a plurality of nucleation cores and forming a catalyst material over the source material. Compositions of matter include a plurality of composite particles, each particle of the plurality comprising a plurality of nucleation cores, a source material disposed over the nucleation cores, and a catalyst material disposed over the source material. Methods of forming earth-boring tools include forming a plurality of composite particles, combining the plurality of composite particles with a plurality of grains of hard material, and catalyzing the formation of inter-granular bonds between the composite particles and the grains of hard material to faun a polycrystalline material. The plurality of in situ nucleated grains of hard material and the plurality of grains of hard material may be interspersed and inter-bonded.

Disclosed herein is a surface treating method using a Taylor reactor wherein a washing, neutralization, heavy metal removal, etc. can be efficiently carried out, while saving a surface treating time and a treatment liquid and enhancing a treatment efficiency by using a Taylor eddy current which in general is formed at a Taylor reactor. The surface treatment method using a Taylor reactor formed of a cylindrical reaction chamber and a cylindrical rotation body which is configured to rotate in the reaction chamber may include (1) a supply step wherein a surface treatment thing and a surface treatment liquid are supplied into the reaction chamber; and (2) a treatment step wherein the surface treatment thing is stayed in the reaction chamber while rotating the cylindrical rotation body, and the stay time of the surface treatment thing is in a range of 1 minute to 6 hours.

A suspension of nanodiamond aggregates according to the present invention is a suspension of detonation nanodiamond aggregates. The suspension has such a pH and an electric conductivity as to meet one of conditions (1) and (2) as follows. (1) The suspension has a pH of 4 to 7 and an electric conductivity of 50 μS/cm or less per weight percent of the solids concentration of the suspension; and (2) the suspension has a pH of 8 to 10.5 and has an electric conductivity of 300 μS/cm or less per weight percent of the solids concentration of the suspension.