| Abstract |
| In order to apply a sacrificial anode cathodic protection system for automotive muffler materials, determination of reliable sacrificial anode and its protection ability were evaluated by laboratory tests in synthetic condensed water. Three kinds of sacrificial anodes were selected: aluminum (AI), zinc (Zn) and magnesium (Mg), and the muffler materials were Al-coated steel and uncoated steel. The corrosion behavior in synthetic condensed water for the muffler materials and sacrificial anodes was investigated by potentiodynamic tests. The cathodic protection ability was evaluated by galvanic corrosion test and weight-loss test. The results of the potentiodynamic test indicated that Al was less suitable for sacrificial anode because it became passive. Mg was also unqualified due to the high dissolution rate. However, Zn was adequate for sacrificial anode because of its low dissolution rate, high stability and suitable potential difference. Results of weight-loss test demonstrated that the corrosion rate of Al-coated steel was reduced from 0.028 to 0.018 mm/year, and that of uncoated steel was 0.08 to 0.002 mm/year by coupling with Zn anode. In addition, the proper area ratio of anode to cathode was 1 : 10. From these results, it can be concluded that Zn anode can protect both the Al-coating with passivation, and steel substrate with low dissolution rate. (Received January 8, 2004) |
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| Key Words |
| Muffler, Condensed water, Sacrificial anode, Cathodic protection system, Galvanic effect prediction, Computer simulation |
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