METHOD FOR SYNTHESIZING TRANSPARENT DIAMOND BY COMBUSTION FLAME METHOD

摘要

PURPOSE:To synthesize diamond of high quality, especially high transparency by directly introducing Ar gas separately from a combustion gas into an inner flame of a combustion flame. CONSTITUTION:For example, in the case of an oxygen - acetylene-based gas, Ar gas is blown from an Ar blowing port 2 in the center of a downwardly fixed burner nozzle 1 and a raw material gas for synthesis is blown from raw material gas-blowing ports 3, arranged around the blowing port 2 and having a smaller diameter than that of the blowing port 2 to prepare a combustion flame shown in the figure. Ar gas is directly introduced into the part of an inner flame 6 in the combustion flame. The combustion flame is then blown toward a substrate 9 to provide a flow as shown in the figure. Excited Ar, together with C-containing active species, such as CH radicals, is converted into a pale radical flame 5 sealed in the interior of the inner flame 6. The activity is enhanced by contact of the Ar radicals with various C-containing radicals and atomic H to provide arrival of more active species at the substrate 9. It is thought that diamond of developed own shape with high quality and transparency is grown in a wide area at a high rate.