伽凡尼腐蝕法探討彩色鍍鋅與鍍鋁鋅鋼片之劣化機構

An Investigation of Degradation Mechanisms of Prepainted Galvanized Steels by Galvanic Corrosion Techniques

彩色鋼片使用中最尋常遭遇問題是由於腐蝕造成剝離或鍍層底材溶蝕現象。本研究以伽凡尼腐蝕電化學方法可追蹤不同環境下所造成鍍層或鍍膜劣化機構。其中在酸雨自然浸蝕環境下主要劣化機構是因陽極溶蝕引起的。而在中性鹽水環境中則是由陰極產生強鹼剝離反應致成的。同時也發現後加工所造成缺陷會加速塗膜下伽凡尼腐蝕現象。最後以酸雨或鹽水浸蝕或噴法模擬實際大氣腐蝕現象並提出三種劣化機構模型。

The most commonly observed corrosion problems of coil coated steels are due to corrosion-induced delamination or undermining processes, especially initiating from edges or damaged regions. The purpose of this research was to study the mechanisms of corrosion and delamination of prepainted Zn or Al-Zn coated steels, with and without post-formed damage. Key words: Galvanic, Corrosion, Mechanisms, Coil coated steel.