Study on microspot splitting characteristics in cathode spot motion of vacuum arc

Abstract

The control of cathode arc spot and the removal of macroparticles have always been key problems in the preparation of coatings of vacuum arc ion plating. This work aims to explore the internal structure and the formation mechanism of cathode arc spot as well as the effects of different parameters on its characteristics. Moreover, the work attempts to find a way to improve the arc spot discharge fundamentally from the inside of the spot by photographing the cathode arc spot dynamically with a high-velocity digital camera. The results show that there are the microscopic phenomena of microspot splitting, microspot accompanying motion and periodic motion in the interior of the cathode arc spot. The continuous self-splitting characteristic of microspot is unstable under the intermittent microexplosive emission mechanism, resulting in periodic splitting and merging. Although the stability of microspot splitting can be relatively improved by adjusting the deposition parameters, the nature of the phenomenon that relatively concentrated discharge occurs periodically under the DC arc cannot be changed. In this work, the idea of promoting arc spot splitting is further analyzed and proposed in the mechanism level, and the feasibility of reducing and refining MPs defects by arc spot splitting is also discussed.