In-Situ Seawater Corrosion of Bare, Diffusion Zinc Treated and Alclad Aluminum Heat Exchanger Materials

The Center for Energy and Environment Research of the University of Puerto Rico, The Trane Company, Kaiser Aluminum and Chemical Corp., and Solar America, Inc. have jointly conducted a corrosion test of bare and zinc diffusion protected 3003 aluminum extrusions and of bare and 7072 alclad 3004 aluminum tubes. From June through November 1981, six feet per second OTEC site ocean surface water was pumped continuously through corrosion specimens which were cleaned of biofouling by brushing or by intermittent chlorination. The bare and diffused zinc treated 3003 as well as the 7072 Alclad 3004 aluminum materials had low corrosion rates, about 0.6 mpy, after 185 days. Heat exchangers of these materials therefore merit further evaluation for sea water service.