Abstract: An interrupting layer of inorganic powder other than diamond is formed on the surface of a substrate and a surface of the interrupting layer is contacted with excited raw material gases containing a carbon source, under conditions suited to depositing of diamond on the interrupting layer. The diamond which is synthesized is separated from the substrate. The use of the interrupting layer, composed of the inorganic fine powders, allows ready separation of the diamond from the substrate and the diamond separated is suitable for diaphragms for speakers, heat conductive plates, cutting tools, semiconductors, etc. by appropriately choosing shapes of the substrate. Further, the resulting diamond film can be pulverized, thereby yielding diamond powders which are useful for abrasive tools, cutting tools, etc.

Abstract: The following are disclosed:a method for synthesis of diamond which is characterized by contacting a gas obtained by excitation of carbon monoxide and hydrogen in such a ratio as carbon monoxide being at least 1 mole % per total of carbon monoxide and hydrogen with a substrate in the presence of a reducing metal.A method for synthesis of diamond which is characterized by contacting with a substrate a gas obtained by excitation of carbon dioxide and hydrogen mixed at such a ratio of carbon dioxide being 0.1-20 mol % per hydrogen.A method for synthesis of diamond by depositing diamond on the surface of a substrate by introducing onto the surface of the substrate a plasma obtained from hydrogen and carbon source gas by irradiation of microwave in a plasma generator which is characterized in that progress of microwave oscillated from one microwave oscillator is divided and thus divided respective microwaves and led to a plurality of plasma generators.

Abstract: The following are disclosed:A method for synthesis of diamond which is characterized by contacting a gas obtained by excitation of carbon monoxide and hydrogen in such a ratio as carbon monoxide being at least 1 mol % per total of carbon monoxide and hydrogen with a substrate in the presence of a reducing metal.A method for synthesis of diamond which is characterized by contacting with a substrate a gas obtained by excitation of carbon dioxide and hydrogen mixed at such a ratio of carbon dioxide being 0.1-20 mol % per hydrogen.A method for synthesis of diamond by depositiong diamond on the surface of a substrate by introducing onto the surface of the substrate a plasma obtained from hydrogen and carbon source gas by irradiation of microwave in a plasma generator which is characterized in that progress of microwave oscillated from one microwave oscillator is divided and thus divided respective microwaves and led to a plurality of plasma generators.