A study of zirconium plasma flow generated by a vacuum arc evaporator

Abstract

In the industry of hard coatings, the vacuum arc evaporator is one of the commonly used devices due to its high productivity, reliability and ability to operate in a non-gaseous medium. Apart from this, the imposition of an external magnetic field allows to control the localization of the arc spots both on the simple and sectioned (i.e. made from different materials) cathode surfaces. Another important feature of the vacuum arc evaporators is their capability to generate multi-charged ions. Applying a high voltage negative bias to the substrate, there can be formed the coatings with high adhesion due to the implantation effect. This paper presents some results of the study of the plasma flows generated by an industrial vacuum arc evaporator with a sectioned disk cathode composed of a zirconium in its central part with a titanium ring surrounding it. The mode of evaporator functioning is such that the arc spot motion gets limited by the zirconium disk, which results in producing the zirconium plasma flow. The quantitative characteristics and the energy distribution function of ions have been measured by a multigrid probe with a retarding potential. It has been proved that the multiply charged ions make up a significant part of the flow. The relations between the detected ion components are found as 87.4% Zr+, 10.6% Zr2+, 1.5% Zr3+ and 0.3% Zr4+. The presence of multi-charged ions is also confirmed by optical spectrometry measurements.