Guo Xinghua

Galvanic Corrosion Behavior of Couples of Hot Rolled Steel SS400 and Cold Rolled Steel ST12 with Two Coatings

Galvanic corrosion behavior of couples of cold rolled steel SS400 and hot rolled steel ST12 with chrome-free Zn/Al coating or Zn/Ni alloy electroplating was studied in 3.5%NaCl (mass fraction) solution by means of potentiodynamic polarization and galvanic method. The results showed that the couple of SS400 and ST12 with Zn/Ni alloy electroplating exhibited a weaker ten- dency of galvanic corrosion, a higher open circuit potential and a smaller galvanic current rather than that with chrome-free Zn/Al coating. While the free-corrosion current of Zn/Ni alloy electro- plating coating was smaller than that of Zn/Al coating. Therefore, Zn/Ni alloy electroplating is ex- tremely promising coating for the auto-mobile fastener to replace the traditional Zn electroplating.