Evaluation of Boronized Steel for Corrosion Resistance Enhancement of Tubing in Soultz-Sous-Forets and Rittershoffen Geothermal Plants

Advanced iron boride protective coatings on carbon steels were tested and evaluated, for the first time, in actual corrosion conditions in the geothermal Rittershoffen and Soultz-sous-Forets sites (France) with positive results. Moreover, large size boronized spools demonstrated high performance in geothermal corrosive flows of NaCl-KCl-CaCl 2 -rich brines and CO 2 -containing steam at 150 o C. Their high performance is related to chemical inertness of crystalline iron borides and to well-consolidated double-layer structure. This boronizing thermal diffusion technology is well suited for inner surface protection of piping and complex shape components, and it could be a cost-effective solution to enhance equipment performance for geothermal applications