Corrosion protection of stainless steel by separate polypyrrole electrode in acid solutions |
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| Authors: | J. Hu H. Zhu Y. Ma T. Yi X. Mao A. Lin F. Gan |
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| Affiliation: | 1. Department of Environmental Engineering, School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (P. R. China);2. Present address: Faculty of Civil Engineering and Geosciences, Department of Materials and Environment, Microlab, Delft University of Technology, Stevinweg 1, 2628 CN, Delft (The Netherlands);3. State Key Laboratories for Corrosion and Protection of Metals, Shenyang 110015 (P. R. China) |
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| Abstract: | Galvanic anodic protection (GAP) of stainless steels by doped polypyrrole (PPy) was investigated using chemically synthesized PPy. Separate PPy powder‐pressed electrodes with different surface areas were prepared. Electrochemical properties of PPy electrodes were studied by open circuit potentials (OCPs) and potentiostatic polarization. PPy powder‐pressed electrodes were coupled with 410‐stainless steel electrodes in different concentrations of sulfuric acid solutions, 5 M phosphoric acid solution, and industrial phosphoric acid solution (5 M phosphoric acid + 0.05% chloride ion). Remarkable shift of OCP to the positive direction and sharp decrease of corrosion rate were observed during the coupling experiments, which implies that 410‐stainless steel was transferred to passive state. Results also showed that PPy electrode with sufficient surface area can provide corrosion protection to 410‐stainless steel electrode in highly corrosive acid solution. Based on the experiment results, GAP provided by PPy and PANi (synthesized under similar conditions) was compared. |
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| Keywords: | 410‐stainless steel acid solution corrosion galvanic anodic protection polypyrrole |
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