Controlled Field Study to Determine the Impact of Dry and Wet Deposition of Air Pollutants on the Corrosion Rate of Galvanized Steel

摘要

In the study galvanized steel panels were exposed for 6 months using an automatic covering device at a materials exposure site located at RTP, NC. Galvanized steel panels were boldly exposed to wet and dry deposition. Another set of panels was mounted on a motor-driven rack that moved the panels under a shelter, thereby preventing rain from falling on them. These panels were sprayed with deionized water during each rain event. IC and AA analysis of the runoff from panels indicated that wet deposition enhances the dissolution rate of Zn surface. Much of the Zn dissolved under both clean rain and dry deposition and total deposition conditions can be accounted for by dry and wet deposition of sulfur species and their reactions of Zn compounds that form on the passive protective film on the galvanized steel panels. This information is essential to the development of a damage model that partitions the effects of wet and dry deposition on galvanized steel.