In the last years geothermal power has become a reliable and significant energy source. Because service conditions in geothermal facilities from deeply located aquifers are critical in terms of corrosion, a very important issue regards materials selection. Preliminary evaluation of the materials suitability represents therefore a valuable strategy to ensure a secure and reliable operation of the facilities. In geothermal applications, the use of high-alloyed materials like stainless steels, duplex steels and nickel-based alloys has been considered as a good alternative due to their remarkable corrosion resistance and appropriate mechanical properties. Nevertheless, the corrosion behavior of those metallic materials in geothermal fluids at service conditions has in many cases not been determined. Laboratory tests including electrochemical investigations and exposure tests at 100 °C and 150 °C showed in fact the limits of suitability concerning localized corrosion of three different high-alloyed materials in the highly saline fluid of the North German Basin.

Subject
Geothermal energy, Materials, Nickel based alloys, Repassivation, Repassivation potentials, Open circuits, Polarization curves, Fluids, Crevice corrosion, Steel, Pitting, Localized corrosion, Stainless steel
Keywords:
duplex steel, stainless steel, nickel-based alloy, geothermal, localized corrosion
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2011
GOV
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