Abstract: An apparatus for depositing a diamond film on a substrate includes a first electrode formed as an enclosed body having a nozzle for jetting thermal plasma opening therefrom and a second electrode of opposite polarity positioned in the nozzle. The apparatus additionally includes a power source for applying a direct current voltage between the electrodes. A gas is fed between the electrodes as a direct current voltage is applied thereto, whereby the gas is formed into a thermal plasma which is jetted through the nozzle. A starting gas feed system is included for feeding gaseous starting compounds for vapor phase deposition to the plasma jet and a powder supplying pipe is provided for feeding a metal powder between the electrodes.

Abstract: A process for forming a diamond gas phase synthesized coating film which is easily controlled and affords a high quality, good adhesion strength diamond film includes a step of forming a mixed layer of a plasma spraying material and diamond by simultaneously conducting plasma injection by a plasma spraying, a first torch and plasma CVD by a CVD plasma, second torch to thereby form a mixed layer on the substrate. The first and second torches are structurally distinct and have respective, separately and selectively controlled plasma generation operating conditions.

Abstract: A diamond film is deposited on a surface of a substrate. The diamond film is attached securely to the substrate by forming a first layer on the surface comprising a mixture of a main component of the substrate and a sintering reinforcement agent for diamond, then forming a second layer comprising a mixture of said agent and diamond on said first layer, and finally forming the diamond film on the second layer.