Compact, controllable electrochemical cell for corrosion protection based on micro-sacrificial anode

Aims

The aim of this project is to reduce the concentration of iron in drinking water and to protect long standing installations against further corrosion. To achieve this aim magnesium is dissolved electrolytically to form both magnesium ions and active magnesium-particles. A compact electrochemical cell will be designed consisting of four magnesium rods which are polarised pairwise and alternating as anodes and cathodes.

The magnesium-particles formed are expected to act as micro-sacrificial anodes providing cathodic protection of the ambient steel inside the pipes.

The project is performed on behalf of perma-trade Wassertechnik GmbH, Germany.

Results

The electrochemically active magnesium-particles can be produced by anodic dissolution of pure magnesium and magnesium-alloys. Their composition was analysed.

• Variation of the polarisation routines did not show any effect on particle size and consistence.

• The effect on corrosion protection was demonstrated. However the area protected by each particle is rather small.

• Gaseous hydrogen forms during the electrolysis and the dissolution of the particles. Its amount must not be neglected in technical systems.

• Due to their large size, the magnesium-particles are not attached to the inner surface of the pipes but are carried away with the water flow. The travel distance within the pipes is not yet determined.

• The formation of magnesiumhydroxide residue might be problematic in technical systems.

Das IGF-Vorhaben Nr. der Forschungsvereinigung DECHEMA e.V., Theodor-Heuss-Allee 25, 60486 Frankfurt am Main wurde über die AiF im Rahmen des Programms zur Förderung der industriellen Gemeinschaftsforschung (IGF) vom Bundesministerium für Wirtschaft und Energie aufgrund eines Beschlusses des Deutschen Bundestages gefördert.