Zairyo-to-Kankyo
Online ISSN : 1881-9664
Print ISSN : 0917-0480
ISSN-L : 0917-0480
Research Paper
Long Term Stability of Zinc-Aluminum-Chromate Composite Baked Coating in 3 wt% NaCl Solution.
Koya TokutakeDaisuke ItoTakashi YokoyamaShinji OkazakiTakahiko OhtaniMitsuhiro KohchiMichiaki NakazatoTakao Higashiyama
Author information
JOURNAL FREE ACCESS

2011 Volume 60 Issue 2 Pages 75-80

Details
Abstract

DACROTIZED® film is one of the anti-corrosion films which are practically applied to automobile small components. In this paper, the anti-corrosion performances of two kinds of DACROTIZED® films in 3 wt% NaCl solution for 90 days were quantitatively evaluated using various electrochemical methods. The mild steel coated with the film which is composed of zinc flake, aluminum flake and chrome binder was used as specimen. The cathode protection duration of this film was found to be about 30 days through the result of corrosion potential monitoring. An EIS study showed almost capacitive response at low frequency range after 75 days immersion. The red rust which was the corrosion products of steel was observed simultaneously. On the other hand, the sacrificial zinc anodes in the film which containing 3% boron compound as additives was kept working over 90 days. The absolute value of impedance of the film containing boron compounds was twice as large as that of the film without boron.
The polarization curve transition with immersion time revealed that zinc corrosion products would gradually accumulate in the film and form stabilized layer after about 14 days. It was suggested that boron compounds not only suppress the excessive dissolution of zinc but also improve barrier properties of the film.

Content from these authors
© 2011 Japan Society of Corrosion Engineering
Previous article Next article
feedback
Top