超音波励振された板状アーク電極からの金属微粒子生成法

Abstract

In recent years, various kinds of powder metal production methods have been developed. The plasma rotating electrode process (PREP) is a typical method but it needs a particular high-speed motor. Authors have proposed a metallic powder production method from an arc-discharge electrode vibrated in an ultrasonic frequency. In this paper, I intend to make production time longer and to produce larger amount of metallic powder. I have adopted a metallic plate of 50×150×6mm in size as a processed ingot instead of a short cylindrical one in my previous trial. The iron plate is energized at its center by a 15kHz-600W ultrasonic power oscillator in this experiment. Both ends of the plate oscillate with amplitude of about 60μm. One end is now heated by an anode spot which is formed by an arc discharge established between the plate and another cathode. When the arc current is taken as 40A, total processing time is attained to 2min and 20g of iron powder is obtained. Diameter of the produced powder is distributed between 30 to 160μm with an average value of 67μm. Remarkable cooling effect are brought about by injecting water drops at a rate of 1ml/s and by blowing He gas at a rate of 50l/min. Processing time as well as producing amount will be expected to be improved with larger arc current and larger plate associated with effective cooling.