E Abbasi - Member of Young Researchers Club of Islamic Azad University of Saveh branch, Iran
M Ahmadi - Expert of Engineering Department, Bahman Motors Company, Iran
M Salmani - Islamic Azad University (Saveh branch), Department of Material and Science Engineering, Iran

As new generation of automotive fuel tank, Sn-%8Zn alloy coated steel sheet are used to manufacture the fuel tank. In this research a modified procedure in order to increase the corrosion and erosion resistance of the Sn-Zn alloy coated steel sheet by using conventional polymeric coating has been contrived. This polymeric coating fulfills enough compatibility with the alloy coating in regard to its typical applications. Several samples are prepared from tin-zinc alloy coated steel sheet with ferrous phosphate, Tricationic phosphate and without any phosphate as pretreatments in addition to polymeric coatings such as Epoxy, Poly Urethane, Polyester and Polyester-Epoxy. For consideration the interaction of paint coating on tin-zinc alloy layer the samples are subjected to some tests such as salt spray, gasoline resistance, moisture resistance, chipping, adhesion, impact, cupping, hardness and microscopic test. As results of investigation, by using Poly ester – epoxy paint with Fe phosphate pretreatment on the tin-zinc coating, the most considerable improvement in corrosion resistance has been reached as well as desirable mechanical and physical properties. Keywords: corrosion, erosion,polymeric coating, pretreatment process, tin-zinc alloy coating.

Corrosion, Automotive, Polymer coating