Arc evaporation

The arc evaporation method is used to apply aluminum, titanium, zirconium and chromium-based hard-material coatings to tools. The starting material for this vacuum-based coating process takes the form of an arc cathode.

In a vacuum chamber, a voltage of several hundred volts is applied between an anode and the positively charged arc cathode. This generates an arc. This moves up and down at the arc cathode and melts or evaporates tiny quantities of material. Approximately 90 % of the evaporated cathode particles form positively charged metal ions. A bias voltage is now applied between the vacuum chamber and the substrate. This accelerates the metal ions in the direction of the workpiece. Here, they react with a reactive gas that is fed in externally (nitrogen, hydrocarbon or oxygen) and are deposited on the workpiece as a fine nitride, carbide or oxide hard-material layer.