Aiming at the goal of preparing high-quality coatings, this paper reviews the progress on circular arc source structure and magnetic field arc controlling technology in arc ion plating (AIP), with a focus on design characteristics of the different structures and configuration optimization of the corresponding magnetic fields. The circular arc source, due to its simple structure, convenient installation, flexible target combination, high cooling efficiency, and high ionization rate and deposition rate, has shown significant application potential in AIP technology. In terms of magnetic field arc controlling technology, this paper delves into the design progress of various magnetic field configurations, including fixed magnetic fields generated by permanent magnets, dynamic rotating magnetic fields, axially symmetric magnetic fields, rotating transverse magnetic fields, and multi-mode alternating electromagnetic coupling fields. By designing the magnetic field distribution reasonably, the trajectory and velocity of the arc spot can be controlled precisely, thus reducing the generation of macroparticles, improving target utilization, and enhancing coating uniformity. In particular, the introduction of multi-mode magnetic field coupling technology has broken through the limitations of traditional single magnetic field structures, achieving comprehensive optimization of arc spot motion and plasma transport. Hopefully, these research advances provide an important theoretical basis and technical support for the application of AIP technology in the preparation for high-quality decorative and functional coatings.

The proper control of cathode spot motion is the key issue in the application of vacuum arc deposition (VAD). Improving the arc spot discharge requires considering the structure and properties of the deposited films/coatings as well as the deposition velocity, target utilization, etc. To achieve this goal, it is necessary to precisely observe cathode spots during discharge at both microscopic and macroscopic scales. However, how to capture the motion and splitting behavior of cathode spots using simple equipment remains an open question. In this work, we analyze the motion and the splitting behavior of cathode spots considering industry application on a Cr target for VAD under arc currents in the direct mode (70 A, 100 A, 150 A 200 A) and 400 A as a peak value in the pulse mode with two applied magnetic fields (20 Gs and 40 Gs) at the macroscopic scale using a high-speed digital camera, employing different exposure times under an extracted interval of 1 ms ranging from 0.01 ms to 20 ms. Furthermore, the images are also compared when the interval is extended to 2 ms and 4 ms. Considering all factors in the available data, 0.05 ms is suggested as the best exposure time, and 1 ms is suggested as the most suitable extracted interval for cathode spot observation under these conditions. Hopefully, this paper provides a suitable technique for observing the motion and splitting behavior of cathode spots at a macroscopic scale with the purpose of suppressing/eliminating the injection of macroparticles at the source for industrial VAD coating products of high quality.