Corrosion protection

Development and testing of novel corrosion protection surfaces for use on offshore structures

University of Applied Sciences Kiel - Faculty of Mechanical Engineering, Institute for Materials and Surface Technology
Prof. Dr. Mohammed Es-Souni

Wind turbines used at sea are exposed to extreme weather conditions. The sensitive plant components must brave the elements, because the failure of components automatically entails higher maintenance and repair costs. Due to the exposed location and the associated longer distances, the costs are much higher than for onshore wind turbines. In the field of offshore wind energy, there is still no extensive experience in terms of corrosion protection. Also, no superordinate rules or standards exist today.

Another aspect to use corrosion protection systems is the prevention of contamination of the seawater with poisons contained antifouling layers. Here, the development of future corrosion protection surfaces aims to be fundamentally environmentally neutral, i. e. no toxic substances are released into the environment.

Two goals have been defined for this project:
  1. The development of corrosion protection coatings for small to medium-sized and geometrically complex components (including shackles, bolts and the like)
  2. The development of transparent antifouling layers for optical parts for online monitoring of underwater structures

The project is funded by the state government of Schleswig-Holstein in accordance with the directive for the granting of grants to promote research, development and technology transfer with state funds and has a term until March 2014.

Activities and goals

Sheets with differently processed surfaces in plastic containers on the footbridge
Sheets with differently processed surfaces in plastic containers on the footbridge

To achieve the first goal, a comprehensive screening program of various ceramic-based systems and hybrid-organic-inorganic-based systems was made. After thorough electrochemical testing, two systems with outstanding properties have finally emerged, which have now been stored on the FINO3 platform since August 15, 2013.

Of particular interest will be the behavior of the hybrid-organic-inorganic layer, since this layer is particularly easy to apply. In addition, this layer can be cured at low temperatures (100 to 140 ° C). It also has a superhydrophobic effect, a property sought for this application. Work on the further development of this layer with regard to mechanical stability, adhesion and scratch resistance is currently being carried out.

Low algae growth on steel sheets after four weeks in the microalgae tank.
Low algae growth on steel sheets after four weeks in the microalgae tank.

The second goal proved to be very ambitious. The antifouling layers should be transparent and free of toxins. They are designed to prevent any attachment of small marine organisms through cargo centers. Again, a comprehensive screening program of cationic molecules and their coupling to transparent substrates was made. For laboratory testing, a microalgae tank was used. After 18 months of development, two molecules have shown promise. These molecules were coupled to a silicon oxide layer and, as shown in the adjacent figure, after a four-week outsourcing, only a few adhesions are observed.

To the results

Results are only available on the German website
FINO3