EFFECT OF ARC CURRENT AND VOLTAGE ON PROD UCTION-RATE OF ULTRAFINE PARTICLES BY AR-H-2 ARE PLASMA METHOD

The are current and voltage were taken as influence factors on the gen eration rate of ultrafine particles using an Ar-H-2 are plasma method and the effect of these factors on the ultrafine particle generation r ate was studied. Two types of the electrode tip shape, that is, the ve rtex angle of 90 degrees and hemisphere, were used to investigate its shape effect on the generation rate. Experiments were mainly carried o ut under Ar-50%H-2 mixed gas at atmospheric pressure, the are generati on condition of 25-40 V and 90-220 A. The generation rate of ultrafine particle under the condition of constant are voltage gives the maximu m value with respect to the are current. The are current which provide s the maximum generation rate has the tendency that does not depend on the are voltage when the electrode of acute shape is used. The are cu rrent dependence of the generation rate under constant are voltage, th ree kinds of the voltage dependence were observed; the generation rate decreases monotonously, increases monotonously and have the minimum v alue with increasing are voltage. The are current and voltage dependen ce of the generation rate is discussed from the view point of the magn itude of velocity of the plasma jet which generates from both the elec trode and the anode heating by electrons.