Investigation of the Corrosion Susceptibility of Flame-Sprayed and Electric-Arc Sprayed Anodic Metal Coatings of Aluminum, Zinc, and an Aluminum-Zinc Alloy

摘要

Anodic coatings of aluminum, zinc, and alloy consisting of 99% aluminum and 1% zinc, applied to a mild steel substrate by either the oxygen-acetylene wire flame spray method or the electric-arc spray method, were evaluated for their corrosion protection abilities. The coatings tested were prepared by the Puget Sound Naval Shipyard using standard production methods. The corrosion testing utilized in the present research included planned interval immersion/emersion, continuous spray, and electrochemical techniques in a solution of 3.5% NaC. The response of the different coatings to the various tests were studied microscopically. The corrosion products were also studied by x-ray spectroscopy and x-ray diffraction. Results of the investigation indicate that coatings of aluminum are the most resistant to corrosion in a simulated, aggressive marine environment, that alloying aluminum with 1% zinc in the coating material has no beneficial corrosion preventive effect, and that a pure zinc coating is unsuited for service in a severe marine environment. (Author)