Scientific Engineering of Anti-Corrosion Coating Systems based on Organic Metals (Polyaniline)

Dr. Bernhard Wessling
Ormecon Chemie GmbH & Co. KG, Ammersbek
(a subsidiary of Zipperling Kessler & Co.)

4. „Scientific Engineering“: a new research and development tool for anti-corrosion coatings

This was the reason why we continued to study and develop other techniques[33] for evaluating those properties which we consider being the key requirements for good corrosion protection performance with Organic Metal coatings,

  1. the ennobling (i.e., the potential shift)
  2. the passivation (i.e., the oxide layer formation)
  3. adhesion of primer (+ top coat) also under corrosive conditions, and resistance against underfilm corrosion (i.e., minimum underfilm corrosion propagation velocity)
  4. optimal barrier properties to be maintained as long as possible under corrosive conditions.

These 4 properties are now measured by us with the following methods:

  1. open circuit potential measurement
  2. a scratch test developed by us
  3. Scanning Kelvin potential measurement (SKP)
  4. electrochemical impedance spectroscopy (EIS), using a new routine FFT technique.

Test 1 and 2 are used as a first screening. Test 3 and 4 are used for advanced screening, before they are combined with an immersion cycling, cycling climate test or salt spray test for those systems which pass the advanced screening successfully.

Industrially useful coating systems have been developed by us following this „Scientific Engineering Method“. The results reported below were found on test panels coated with PAni containing primer CORRPASSIVTM [34] applied with a thickness of 20 µm and coated with various top coats.


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