Galvanic corrosion of Ni–Cu–Al composite coating and its anti-fouling property for metal pipeline in simulated geothermal water

A novel anti-fouling epoxy-silicone composite coating containing Ni–Cu–Al alloy powder for metal pipeline in geothermal water was fabricated based on the basic principles of galvanic corrosion. Fouling behaviors of the surface of composite coating in the simulated geothermal water were studied in comparison with stainless steel and epoxy-silicone resin coating. The results indicated that composite coating possessed a good anti-fouling performance. In the geothermal water, Ni2+, Cu2+ and Al3+ ions, originated from interface electrochemical corrosion, were released into bulk solution. These metal ions intensively inhibited nucleation and crystal growth rate of CaCO3 fouling on the surface of composite coating, and promoted precipitation of CaCO3 fouling in the bulk-solution, which could be easily washed away by flowing water. But for 304 stainless-steel and epoxy-silicone resin coating, CaCO3 fouling grew easily and adhered firmly to their surfaces, and influenced the transport efficiency of geothermal water for pipelines.