An object of the present invention is to provide composite particles capable of suppressing oxidation over time of a Si—C composite material. Composite particles (B) of the present invention contains composite particles (A) containing carbon and silicon; and amorphous layers coating surfaces thereof, where the composite particles (B) have I.sub.Si/I.sub.G of 0.10 or more and 0.65 or less, and have R value (I.sub.D/I.sub.G) of 1.00 or more and 1.30 or less, when a peak due to silicon is present at 450 to 495 cm.sup.−1, an intensity of the peak is defined as I.sub.Si, an intensity of a G band (peak intensity in the vicinity of 1600 cm.sup.−1) is defined as I.sub.G, and an intensity of a D band (peak intensity in the vicinity of 1360 cm.sup.−1) is defined as I.sub.D in a Raman spectrum, and where the composite particles (B) have a full width at half maximum of a peak of a 111 plane of Si of 3.0 deg. or more using a Cu-Kα ray in an XRD pattern.

A method of manufacturing a diamond substrate includes: forming an ion implantation layer at a side of a main surface of a diamond seed substrate by implanting ions into the main surface of the diamond seed substrate; producing a diamond structure by growing a diamond growth layer by a vapor phase synthesis method on the main surface of the diamond seed substrate, after implanting the ions; and performing heat treatment on the diamond structure. The performed heat treatment causes the diamond structure to be separated along the ion implantation layer into a first structure including the diamond seed substrate and failing to include the diamond growth layer, and a diamond substrate including the diamond growth layer. Thus, the method of manufacturing a diamond substrate is provided that enables a diamond substrate with a large area to be manufactured in a short time and at a low cost.

A method of manufacturing a diamond substrate includes: forming an ion implantation layer at a side of a main surface of a diamond seed substrate by implanting ions into the main surface of the diamond seed substrate; producing a diamond structure by growing a diamond growth layer by a vapor phase synthesis method on the main surface of the diamond seed substrate, after implanting the ions; and performing heat treatment on the diamond structure. The performed heat treatment causes the diamond structure to be separated along the ion implantation layer into a first structure including the diamond seed substrate and failing to include the diamond growth layer, and a diamond substrate including the diamond growth layer. Thus, the method of manufacturing a diamond substrate is provided that enables a diamond substrate with a large area to be manufactured in a short time and at a low cost.

An apparatus for fabricating diamond by carbon assembly, which comprises:

a) a hydrocarbon radical generator in operable connection with
b) a mass flow conduit extending from the hydrocarbon radical generator in a) to an interface and into a primary magnetic accelerator containing one or more electromagnets in operable connection with
c) a diamond fabrication reactor comprising a diamond forming deposition substrate.

Also disclosed is a method for fabricating diamond by shockwaves using the disclosed apparatus.

A diamond crystal substrate has a substrate surface that is one crystal plane among (100), (111), and (110) and that has atomic steps and terraces structure at an off-angle of 7° or less excluding 0°.

A diamond crystal substrate has a substrate surface that is one crystal plane among (100), (111), and (110) and that has atomic steps and terraces structure at an off-angle of 7° or less excluding 0°.

A method for forming a diamond product. Diamond material is provided and a damage layer comprising sp.sup.2 bonded carbon is formed in the material. The presence of the damage layer defines a first diamond layer above and in contact with the damage layer and a second diamond layer below and in contact with the damage layer. The damage layer is electrochemically etched to separate it from the first layer, wherein the electrochemical etching is performed in a solution containing ions, the solution having an electrical conductivity of at least 500 μS cm.sup.−1, and wherein the ions are capable of forming radicals during electrolysis. The diamond product is also described.

A method for forming a diamond product. Diamond material is provided and a damage layer comprising sp.sup.2 bonded carbon is formed in the material. The presence of the damage layer defines a first diamond layer above and in contact with the damage layer and a second diamond layer below and in contact with the damage layer. The damage layer is electrochemically etched to separate it from the first layer, wherein the electrochemical etching is performed in a solution containing ions, the solution having an electrical conductivity of at least 500 μS cm.sup.−1, and wherein the ions are capable of forming radicals during electrolysis. The diamond product is also described.

One variation of a method includes: ingesting an air sample captured during an air capture period at a target location for collection of a first mixture including carbon dioxide and a first concentration of impurities; conveying the first mixture through a liquefaction unit to generate a second mixture including carbon dioxide and a second concentration of impurities less than the first concentration of impurities; in a methanation reactor, mixing the second mixture with hydrogen to generate a first hydrocarbon mixture comprising a third concentration of impurities comprising nitrogen, carbon dioxide, and hydrogen; conveying the first hydrocarbon mixture through a separation unit configured to remove impurities from the first hydrocarbon mixture to generate a second hydrocarbon a fourth concentration of impurities less than the third concentration of impurities; and depositing the second hydrocarbon mixture in a diamond reactor containing a set of diamond seeds to generate a first set of diamonds.

One variation of a method includes: ingesting an air sample captured during an air capture period at a target location for collection of a first mixture including carbon dioxide and a first concentration of impurities; conveying the first mixture through a liquefaction unit to generate a second mixture including carbon dioxide and a second concentration of impurities less than the first concentration of impurities; in a methanation reactor, mixing the second mixture with hydrogen to generate a first hydrocarbon mixture comprising a third concentration of impurities comprising nitrogen, carbon dioxide, and hydrogen; conveying the first hydrocarbon mixture through a separation unit configured to remove impurities from the first hydrocarbon mixture to generate a second hydrocarbon a fourth concentration of impurities less than the third concentration of impurities; and depositing the second hydrocarbon mixture in a diamond reactor containing a set of diamond seeds to generate a first set of diamonds.