以交流阻抗技術研究有機與鋅粉塗料之行為

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

林漢棠(Lin Hang Tang)

指導教授 ： 尹庚鳴

元智大學/工程學院/化學工程與材料科學學系/碩士(2001年)

摘要

為了解高分子塗層在溶液中劣化的行為，選用黑鐵片塗佈防蝕塗層做為實驗試片。實驗塗層分為兩大類。第一類選擇環氧樹脂做為塗層，以黑鐵片進行空白實驗。塗層製作方式以旋轉塗佈製作。測試環境分別為0.5M NaCl、0.1M HCl、0.1M HNO3及0.1M H2SO4；第二類則以鋅粉為塗料，加上環氧樹脂為結合料以製成Zinc Rich Paint(ZRP)。塗料分為商用及自製兩種，並以鍍鋅鋼板進行空白實驗。自製塗料以噴塗法及刮塗法製作。測試環境分別為0.5M NaCl、0.1M HCl。
測試項目分為1.交流阻抗(ac Impedance)、2.開路電位隨時間的變化、3.表面外觀分析(SEM)，其中ZRP試片並做4.腐蝕電流的觀察。藉由頻率範圍從1M Hz~50m Hz的交流阻抗頻譜分析去建構一套電阻-電容等效電路模型用以描述溶液/塗層/金屬界面的腐蝕行為。並且以開路電位的變化與SEM的外觀變化加以比較。再者，改變塗層的鋅粉百分比與厚度，觀察這些參數對塗層腐蝕性質的影響。
實驗結果得到純環氧樹脂在NaCl環境中具有相當良好的抗腐蝕能力，而ZRP初期則表現出較低的阻抗，這符合了鋅具有犧牲陽極的特性。而實驗後期鋅消耗並氧化為氧化鋅，再加上鐵被曝露在溶液中，因此觀察到阻抗值會較初期提高。

關鍵字

電化學交流阻抗 ； 阻抗 ； 富鋅塗料 ； 極化電阻法 ； 環氧樹脂 ； 等效電路 ； 腐蝕

並列摘要

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.

並列關鍵字

EIS ； Impedance ； Zinc Rich Paint(ZRP) ； Polarization Resistance ； Epoxy Resin ； Equivalent Circuit ； Corrosion

參考文獻

1.E. Mattsson , “Basic Corrosion Technology for Scientists and Engineers” , Ellis Horwood , Chichester , UK , 1989.

10.F. Masfeld , Corrosion , 44 , pp.856. 1988.

19.C. G. Munger , Corrosion Prevention by Organic Coatings , NACE , Houston , 1984.

20.J. E. O. Mayne , J. Soc. Chem. Ind. , 66 , pp.93. 1977.

21.F. Theiler , Corrosion Science , 14 , pp.405-414. 1974.