Corrosion protection methods
The aim of corrosion protection is to prevent as far as possible any damage that can occur as a result of rust to construction or machine parts. Total resistance to corrosion is, however, not achievable in practice. The challenge is therefore to ensure the longest possible protection for the part to be protected in order to extend its service life. Two approaches are used to achieve this:
Corrosive agents, i.e. substances that promote corrosion such as oxygen and salts, get directly influenced in the corrosion reaction by appropriate protective mechanisms. This can be achieved by using inhibitors, which, by the way they work, reduce the corrosiveness of such substances. Another way of granting active protection can be achieved through the build-up of so-called sacrificial anodes, which protect a component from corrosion by cathodic means. Another option for cathodic protection is offered by the use of current from an external source. Here any different electrochemical potentials between components and surroundings get compensated.
Substances that lead to corrosion are kept at bay by measures taken to shield the component to be protected. A protective coat is often applied to them. A key requirement for effective passive corrosion protection is appropriate pre-treatment of the surface.
Each measure can be used on its own. However, a combination of several measures is frequently essential for effective protection – and can also often be inexpensively achieved. Some measures also work both actively as well as passively.
The literature offers a large number of strategies for active and passive corrosion avoidance.
 Vgl. Baeckmann, W.v., Schwenk, W., Handbuch des kathodischen Korrosionsschutzes, Wiley-VCH Verlag, Weinheim, 1999