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Vol.41, No.9, 585 ~ 594, 2003
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| Title |
| Effects of Alloying Elements(Cr, Co, W, Cu, Ni, Ca) on the Corrosion Behavior of Low Carbon Steel in Synthetic Tap Water |
| 심재주 Sim Jae Ju , 최윤석 Choe Yun Seog , 김정구 Kim Jeong Gu |
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| Abstract |
| This paper presents the corrosion behavior of the low alloy steel contained alloying elements such as Cr, Co, W, Cu, Ni and Ca in synthetic tap water using potentiodynamic polarization tests, electrochemical impedance spectroscopy (EIS), XPS and EPMA. Potentiodynamic poalrization curves indicated that all the specimens had active corrosion behavior. Corrosion rate tended to reduce as the result of the alloying. Also, EIS test results showed that the more the content of element, the larger the polarization resistance. It can be seen that these results were caused from the formation of a coherent, protective film contained alloying elements. Actually, XPS results showed that Cr, Cu, and Ca were formed as protective metal oxides at the surface of rust film under the stagnant condition. The results of EPMA indicated that Cr, Cu, and Ca were distributed densely at the inner layer of the rust film, while Co, W, and Ni were distributed at the whole layer under the flow condition. Consequently, alloying elements improved corrosion resistance of low alloy steel in synthetic tap water. Especially, Cr, Cu, Ni, and Ca-containing specimen had the lowest corrosion rate due to the inner rust film formation during the initial stage of corrosion, which suggested a potential substitute for carbon steel in potable water system. |
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| Key Words |
| Carbon steel, Tap water, Alloying elements, Rust layer, Corrosion behavior |
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