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Vol.41, No.12, 909 ~ 916, 2003
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| Title |
| Effects of Alloy Elements Cr, Co and W on the Corrosion Behavior of Low Carbon Steel in Synthetic Seawater |
| 심재주 Sim Jae Ju , 유승재 Yu Seung Jae , 최윤석 Choe Yun Seog , 김정구 Kim Jeong Gu , 유장용 Yu Jang Yong |
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| Abstract |
| The aqueous corrosion characteristics of 1% Cr-steel alloyed with small amounts of Co and W, in synthetic seawater was studied by using immersion weight-loss tests, electrochemical corrosion tests (potentiodynamic test and electrochemical impedance spectroscopy (EIS) measurements) and analytical techniques. 1% Cr steels containing Co or W from 0.2 to 0.4 wt.% showed higher corrosion resistance than the 1% Cr steel in the immersion and potentiodynamic tests. EIS measurements showed that the Nyquist plot presented one time constant. Furthermore, the Co- and W-bearing steels present higher Rp values than the 1% Cr steel through all the test period. The better corrosion resistance of the Co-and W-bearing steels is attributed to protectiveness of the surface layer. The corrosion products were examined using electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). The results of EPMA indicated that Cr was concentrated in the inner region of the rust layer, while Co and W were distributed all over the rust layer. XPS results showed that Co existed as a trivalent oxide in the rust layer and W in the rust appeared in the form of a WO₄ compound. |
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| Key Words |
| Alloying element, Carbon steel, Seawater, EIS, Aqueous environments, Rust layer, Corrosion behavior |
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