IVD coating processes are performed as follows: First of all, the components to be coated are degreased to remove any machining or dewatering oils. The next process step consists in fine sandblasting. On the one hand, the surface is mechanically cleaned; on the other hand, a profile with a large surface is created. The latter supports the coating’s physical bonding with the substrate.
During the process, the parts remain fixed on an electroconductive rack inside a vacuum coating chamber. The parts are moved into the coating chamber, which is then evacuated. Inert gas is then led into the chamber, while electric voltage is applied. This leads to plasma glow discharge, which manifests itself in a violet glow inside the chamber. The result: a very clean surface on the substrate.
After this process has been completed, the actual coating process can start. Aluminum wire is now added to a series of overheated ceramic crucibles. High voltage is then applied to generate very high temperatures, whereupon the aluminum turns into electrically charged vapor. The negatively charged aluminum atoms move through the vacuum and deposit themselves onto the parts to be coated, which are electrically grounded.