AC Impedance Technique to Study the Behavior of Organic and Zinc Rich Coatings

• Main Authors: Lin Hang Tang, 林漢棠
• Other Authors: Yin Ken Ming
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/66606012068654397635

碩士 === 元智大學 === 化學工程研究所 === 89 === To understand the behavior that the polymer coatings deteriorated in solution, selected iron plate that was spread by anti-corrosion coatings to be sample. And coatings had two types. First type used epoxy resin to be coating and used iron plate to do blank test. The making method of coating was spin coating. The solutions were 0.5M NaCl、0.1M HCl、0.1M HNO3 and 0.1M H2SO4; Second type, Zinc Rich Paint(ZRP) was made by using zinc powder to be paint and epoxy resin be binder. Paints were divided into commercial and ours, and used galvanized steel to do blank test. The making methods of our coatings were spraying and spreading. The solutions were 0.5M NaCl and 0.1M HCl. The measurements included 1.ac Impedance、2.OCP vs time、3.surface visual analysis(by SEM) and ZRP add 4.the test of icorr vs time. Electrochemical Impedance Spectroscopy (EIS) in the 1M Hz~50m Hz frequency rangy was applied to construct a resistance-capacitance equivalent circuit model to simulate the corrosion behavior in solution/coating/metal interface system. And compare with the variation of OCP and visual surface by SEM. Also, observe the influence of coating’s corrosive properties by changing some coating’s parameters like percentage of zinc and thickness. As a result, epoxy resin had good anti-corrosion property in NaCl environment. But ZRP revealed lower impedance as initial, this consisted with the characteristic that zinc was sacrificial anode. In latter period, zinc was dissolved and oxidized to be zinc oxide. And iron was exposed to solution, so we can observe the risen impedance than former period.