Corrosion Science and Technology

The Corrosion Science Society of Korea (한국부식방식학회)
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Corrosion Behavior of Zn and Zn-AI Alloy Coated Steels under Cyclic Wet-dry Environments

  • Nishikata, Atsushi (Department of Metallurgy and Ceramics Engineering Tokyo Institute of Technology) ;
  • Yadav, Amar Prasad (Department of Metallurgy and Ceramics Engineering Tokyo Institute of Technology) ;
  • Tsutsumi, Yusuke (Department of Metallurgy and Ceramics Engineering Tokyo Institute of Technology) ;
  • Tsuru, Tooru (Department of Metallurgy and Ceramics Engineering Tokyo Institute of Technology)
  • Published : 2003.08.01
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Abstract

Atmospheric corrosion behaviors of Zn, Zn-5%Al and Zn-55%A l coated steels have been investigated under cyclic wet-dry environments containing chloride ions. The wet-dry cycle was carried out by alternate exposure to immersion in 0.5 M (or 0.05 M) NaCl solutions and drying at $25^{\circ}C$ and 60 %RH. The polarization resistance $R_p$ and solution resistance $R_s$ were monitored by AC impedance technique. From the obtained $1/R_p$ and $1/R_s$ values, the corrosion rate of the coatings and the Time of Wetness (TOW) were estimated, respectively. Effects of chloride ions and TOW on the corrosion rates of Zn, Zn-5%Al, Zn-55%Al coatings and appearance of red rust (onset of underlying steel corrosion) under wet-dry cycles are discussed on the basis of the corrosion monitoring data.

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References

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