导电高分子防腐蚀涂层的防腐蚀能力

美国北塔科他州立大学高分子涂层研究组用SVET技术表征了一种导电高分子涂层对Al 2024-T3合金的防腐蚀能力。用SVET技术得到的局部电流图，表明导电高分子通过对氧气的溶解来改变金属表面的腐蚀行为。（Journal of The Electrochemical Society）

current density map and optical micrograph withsuperimposed current density vectors for Ppy/DBA coating on Al 2024-T3with scribe after 10 min immersion in DHS.

An oxidation current was observed within the scribe, and its magnitude reached about 800 mA/cm2 after just 10 min immersion. The reduction current was distributed uniformly across the conducting polymer surface, which suggests that either an oxygen reduction reaction occurred at the electrolyte/conducting polymer interface and/or the Ppy film itself was reduced. The defect area remained shiny throughout the 24 h immersion period, and no corrosion products were observed in thesolution, suggesting that soluble corrosion products formed within the defect area. Toward the end of the immersion period, the current dropped to ca. 10 mA/cm2, indicating that passivation was occurring. This behavior is in contrast to that observed at a typical inert coating such as epoxy primer where both oxidation and reduction occur within the defect area and insoluble corrosion products formed extensively within the scribe region.

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