Corrodium anodes are sacrificial anodes which are controlled by electronics. The anodes are made of zinc or aluminium for seawater or brackish water, or magnesium for fresh water. They don’t require a battery, the anode current charges a capacitor to 4,5 Volt in order to operate the electronic circuit. Often Corrodium anodes are used for fighting galvanic corrosion as the overall protection potential can be set to a ideal value, e.g. -850 mV Ag/AgCl. Corrodium anodes are controlled by electronic components, are self operating and can be switched to zero-resistance. The robustness and liftetime of Corrodium anodes is similar to that of any other sacrificial anode. No cables, no power supply and no batteries. The anode (aluminium) and cathode (stainless/carbon steel) themselves function as ‘seawater battery’. Corrodium anodes have 2 functions:
- Controlling the protection potential. For example, to avoid hydrogen embrittlement of duplex stainless steel seawater liftpumps.
- Providing a pulse to the object to be protected. For example this is done with stainless steel sandbed filters in swimming pools. The pulse doubles the anode life and it fights the formation of (corrosive) biofilms. Micro organism don’t like a pulse because it constantly alters the pH of the surface layer.
Below a NACE paper about Corrodium anodes:
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