Materials and Electronic Equipment Corrosion Tests in Some U.S. Navy Geothermal Environments.

摘要

This report documents the results of geothermal corrosion studies conducted at the Coso Geothermal Area, Naval Weapons Center (NWC), China Lake, Calif., and the Naval Air Station (NAS), Fallon, Nev. At the Coso Geothermal Area, five different metallic and nonmetallic materials in tubular shapes were tested for approximately 17 months in two different types of low-pressure, medium-temperature steam environments. In addition, a variety of electronic equipment including aircraft instrumentation and battery-powered test circuits were exposed to a hydrogen-sulfide-rich environment at the Devils Kitchen area for approximately 2 years. At NAS, Fallon, standard corrosion coupons of 11 different metals and alloys and some plastic cement samples were exposed to fluids in a deep brine well for three different time intervals up to 109 days (a planned-interval test series). Exposed samples were analyzed using a variety of methods including optical microscopy, x-ray diffraction techniques, and weight-loss measurements. Corrosion rates, modes, and various corrosion products and precipitates were established for the individual coupons and the tubular specimens, while the electronic instruments and test circuitry were given an operational and bench test before and after exposure and were also visually inspected. Test circuits (and one electronic instrument) were also periodically removed and tested. Results of these three differetn test programs are discussed individually and ecom