The use of zinc for corrosion protection is problematic in terms of zinc availability.
This is why Daimler AG only uses galvanized panels (and even then, only in combination with organic protective coatings) in locations where extreme corrosion strain can be expected, e.g. due to road salt.
Corrosion protection using zinc
There are numerous ways of galvanizing steel (plate).
The corrosion protection that is provided by coating with zinc occurs because of the electrochemical reaction between the protective metal (zinc) and the basic material (steel).
The zinc represents the anode and the steel base metal represents the cathode.
Being a base metal, the zinc goes into solution.
The surface of the steel is therefore not attacked.
By accurately checking and weighing economic and ecological aspects, a composite design (a combination of different materials) depending on the profile of requirements has proven its worth.
Different plastics and aluminum are being used more frequently as basic materials in areas that are susceptible to corrosion.
The cathodic protective effect of the zinc can be explained by examining positions of zinc and steel in the electrochemical series.
This is known as zinc acting as the sacrificial anode.
In combination with organic protective coatings, this produces the best possible corrosion protection.
If the protective zinc coating is broken through at any point, a local galvanic cell is created because of the effect of the electrolyte (aqueous, electrically conductive solution).