PRODUCTION METHOD FOR LOW OXYGEN SPHERICAL METAL POWDER USING DC THERMAL PLASMA PROCESSING

摘要

PROBLEM TO BE SOLVED: To provide a production method for low oxygen spherical metal powders with its oxygen content controlled to the amount of 1000 ppm or less by DC thermal plasma processing.;SOLUTION: This is a production method for low oxygen spherical metal powders containing 1000 ppm or less oxygen, using a DC power supply to generate DC thermal plasma through which raw material metal powders are passed and processed. The plasma operation gas of this production method uses a mixed gas comprising an inert gas having purity of 99.9% or more in volume and hydrogen gas having purity of 99.9% or more in volume. The amount of hydrogen is 0.5-20 vol.% of the mixed gas. Under this production method the maximum temperature of the zone of the DC thermal plasma through which raw material metal powders pass my be retained at the melting point of the metal powder or higher but not higher than 10000°C. Furthermore, it may be possible to combine the conditions mentioned above. In concrete, any practice should control the oxygen content in the raw material metal powder to 1000 ppm or less.;COPYRIGHT: (C)2002,JPO