A Novel Method to Generate Multicomponent Metal Ions by Anodic and Cathodic Vacuum Arc Plasmas with Pure Electrodes

Usually multicomponent ions are generated from cathodic vacuum arc plasma with compound cathodes. In this paper, a novel method to produce multicomponent ions by simultaneous anodic and cathodic vacuum arc plasmas with pure electrodes has been studied. The vacuum arc discharge has been operated with Al anode and W cathode. To characterize the plasma plume generation, a combination of high-speed camera and time-of-flight mass spectrometer has been used to measure the spot phenomenon and multicomponent ions, respectively. Luminous spots have been simultaneously found on the anode and cathode to produce multicomponent ions, which has been verified by the examination of electrode erosion using SEM. The ion charge state distribution and multicomponent ions have also been measured. For comparison, the characteristic of vacuum arc discharge operated with the exchange of electrodes has been studied, which exhibits obvious discrepancies. This behavior of vacuum arc is considered to be controlled by the difference of cohesive energy, because the heat flow to the electrodes is sufficient to evaporate the electrode, and the ionization process by the plasma occurs in the nonequilibrium layers near the evaporated surface in cathode and anode regions. This interesting result is proposed to use for the synthesis of compound films.