Corrosion Behavior of a Vehicle Submitted in Service in Subtropical Marine Environment of Okinawa Island for Eight Years

A passenger vehicle in the subtropical marine environment of Okinawa Island for eight years was submitted for corrosion investigation.The precoated sheet steels such as Zn-Ni and Zn-Fe showed excellent corrosion resistance in the door hem flange and a scribed outer panel, compared to cold rolled steel. Cosmetic corrosion of a North America vehicle was more severe than that of a Okinawa vehicle, but a similar corrosion rate for perforation was shown in door hem flange. Basic zinc chloride and β-FeOOH were observed by using micro X-ray diffraction method in the initial stage of corrosion, and then these changed to ZnO and α-FeOOH, Fe304.