Corrosion and Surface Technology
Plasma electrolytic oxidation (PEO) coating
The WZK department develops fault-tolerant anti-corrosion coatings which remain effective even when subjected to mechanical damage as well as coatings for magnesium-based medical implants that dissolve in the body according to a set timetable. Although magnesium is not a precious metal, magnesium-based materials are corrosion resistant when exposed to air. In fact, protection against corrosion is only necessary when they are exposed to aggressive media such as sea water or a saline, humid atmosphere. A special care about protection of magnesium should be taken when it is used as a part of multi-material system being joined — by means of welding, for example — to other, more precious metals. Therefore development of active multi-functional coatings for hybrid-structures is one the main focus of WZK.
In addition to corrosion, mechanical loads can also lead to sudden failure when components crack due to stress corrosion or corrosion fatigue. Such failures, the nature of which the WZK department is currently investigating, are caused by hydrogen, which is the primary product of magnesium corrosion.