Effect of arc current and voltage on production rate of copper ultrafine particles by Ar-H-2 arc plasma method

Production of copper ultrafine particles by means of an Ar-H-2 are plasma m ethod was performed using a graphite crucible. The are voltage and the are current were taken as the influence factors affecting on the generation rat e of ultrafine particles and the effect of these factors on the generation rate was studied. The temperature of the crucible close to the melted sampl e was measured and the relation between the temperature and the generation rate was investigated. Experiments were carried out under an Ar-50%H-2 mixed gas at atmospheric pr essure and the are generation condition of 25 similar to 40 V and 90 simila r to 220 A. The generation rate of ultrafine particles at constant are voltage increase d with increasing are current and increased with increasing are voltage at constant are current. However, when the generation rate was arranged with a n electric power as a product of the voltage and the current, it depended s olely on the electric power. These results were discussed from the viewpoin t of the velocity of the plasma jet generated from the cathode and an anode heating by electrons. The temperature of the crucible increased with increasing electric power an d had a tendency to approach saturation. The temperature was affected inten sively by an average temperature of the melted sample, so that an evaporati on enthalpy of copper was obtained as a value of 170-230 kJ/mol using the r ate process based on the assumption that the measured temperature is the va porization temperature of the sample.