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P. Linhardt:
"Moderne Korrosionsschutzsysteme für erdüberdeckte Rohre aus duktilem Gusseisen";
Vortrag: Kongress Guss-Rohrsysteme 2016, Wien (eingeladen); 14.03.2016 - 15.03.2016.

The basic electrochemical corrosion mechanism is briefly introduced and with reference to the standard EN 12501, the corrosion scenarios relevant for buried cast iron pipes are reviewed:
> in homogenous soil
> in artificial soil
> under differential aeration
> by remote cathodes
> by stray currents
The principal corrosion protection methods are derived from these scenarios: (1) separation of the metal from the environment by a coating, and (2) cathodic protection.
The implementation of these two concepts in the standard EN 545 by barrier coatings and by duplex coatings is discussed with respect to advantages and disadvantages. The standard´s requirement related to "evidence for long term behaviour" is discussed for duplex coating systems.
Based on the corrosion protecting mechanism of duplex coatings, a possible practical approach for a testing methodology is presented. An example of testing for a specific parameter related to a duplex coating´s corrosion protection performance is provided.

ductile cast iron, corrosion protection, coatings, duplex coatings