Arc process (vacuum arc deposition)
The arc technology is one of the standard methods for producing nitride hard coatings and can be advantageously used for many other types of layers. Numerous developments around the arc technology have been applied in the IWS.
Vacuum arc discharge
The vacuum arc is a highly ionized gas discharge, which burns in the vapor, generated by itself. It is now the dominant source for industrial hard coating.
Vacuum arc discharge, left: focal spots move over the cathode, which is successively removed
Right: Schematic diagram of a vacuum arc discharge
The principal components of operating a vacuum arc discharge are shown in the picture, especially the vacuum chamber, the cathode, the anode and the current source. The discharge burns in the ionized vapour of the cathode material and is, therefore, mainly independent of the ambient pressure. Principally, vacuum arc discharges can be operated from ultrahigh vacuum to atmospheric pressure in the area. The characteristics of the discharge at higher pressures approach the atmospheric arc discharge.
The industries use the vacuum arc primary for hard coating of tools.
Diagram of a vacuum arc coating system, main components are the vacuum chamber with pumping system, the arc sources (usually installed inside of the chamber walls) and the usually rotating substrate holder with multiple axes.
In addition, gases may be fed to the deposition reactive generated layers.