交流阻抗法研究含氯環境下苯駢三氮五圜對銅之腐蝕抑制行為

Use impedance technology to investigate the inhibition of copper corrosion in the chloride acid solution with Benzotriazole

黃俊傑(Huang Ching-Chieh)

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(2002年)

摘要

本研究以交流阻抗技術在開環電路電位(腐蝕電位)下觀察銅表面的腐蝕行為，同時也在相對於開環電路電位極小的電位範圍內使用極化電阻法，由於這些方法所產生的電流極小，可以視為是一種非破壞性檢測技術，本實驗是以此非破壞性的交流與直流技術持續觀察銅在含氯離子溶液中的腐蝕以及腐蝕抑制劑 (BTAH)對銅的腐蝕影響。
銅電極在含有氯離子及BTAH的酸性或中性環境中，使用電流、阻抗以及表面分析等方式研究BTAH在銅表面所形成的鈍化層。在酸性溶液中腐蝕抑制劑會在銅的表面形成化學吸附，由低掠角反射紅外光譜儀可測得此一化學鍵結。實驗中發現銅電極的表面阻抗隨著BTAH的濃度增加或氯離子濃度的降低而變大。在銅盤電極實驗中可觀察到電極表面有質傳及化學反應的控制機制，而靜置實驗中所觀察到的擴散現象來自溶液中的因素影響更大， Cu-BTA在表面形成的薄膜在不同的實驗條件下有不同的阻抗特性。藉由觀察交流阻抗圖譜中高頻區所呈現的半圓可以觀察BTAH以及亞銅錯離子對於電荷轉移電阻以及電雙層電容的影響。由交流阻抗實驗所得到的結果發現腐蝕的過程極有可能是由氧化層的擴散所控制。這些結果由極化曲線和極化電阻法的資料得到很好的佐證。
在長時間浸置實驗中，BTAH對銅的腐蝕抑制劑效果在40℃所得到的效果比在25℃時的效果還要好。BTAH在較為緩和的條件下(pH=4及7)對陽極反應有抑制作用。在pH=1的狀況下就失效。腐蝕抑制的行為，除了溫度及酸鹼值的效應，同時也存在著一價銅與BTAH交聯聚合形態的薄層。腐蝕過的表面由掃描式電子顯微鏡(含元素分析)以及x-射線繞射儀的測定結果，顯示銅的表面主要是覆蓋一層氧化亞銅(CuO)。在有添加BTAH的特定條件下則發現氯化亞銅(CuCl)與BTAH是共同存在的。
[關鍵字: 交流阻抗、腐蝕抑制劑、銅、苯駢三氮五圜、氯離子。]

關鍵字

交流阻抗 ； 腐蝕抑制劑 ； 銅 ； 苯駢三氮五圜 ； 氯離子

並列摘要

Use of impedance technology under the open circuit potential (corrosion potential) to investigate the copper surface corrosion， also to use polarization resistance that apply narrow range of potential relative to open circuit potential. We can take them as nondestructive testings， and mainly apply both AC and DC nondestructive methods to investigate the copper corrosion and inhibition effect of benzotriazole (BTAH) on the copper surface.
Cu electrode behavior in Cl－and BTAH containing acid or neutral solution was studied by，impedance measurement and chemical analysis of BTAH consist in passive layers. At low solution pH， single molecule of inhibitor is adsorbed chemically on copper and it is demonstrated by low angle reflectance FT-IR spectrum. It was found that the impedance of the copper surface increased by increasing the BTA-concentration and by decreasing the Cl－-concentration. The corrosion of copper in hydrochloric acid solutions at rotating disk electrode was found to be controlled by both mass transfer and reaction. But the anodic process， at the static test， was controlled not only by a mixed diffusion of copper ions in oxide films but also in solution， the impedance characteristics of the Cu-BTA surface film was established under various experimental conditions. The first (high frequency) semicircle is due to the charge-transfer resistance for BTAH and the simultaneous cuprous complex coupled to the double-layer capacitance. Impedance measurement results suggested the corrosion process possibly was controlled by diffusion in the oxide films. Support for these results was obtained from the data of potential dynamic measurements and polarization resistance method.
The inhibiting effect of BTAH， at the static test ，at 40℃showed good inhibition effect than that at 25℃ from short up to extended periods of time. Inhibition of the anodic dissolution reaction was obtained in near-neutral pH solutions (at pH=4 and 7). Inhibition was ineffective at pH=1. The characteristics of the inhibition behavior， including temperature and pH effects， were proposed with an inhibiting film that formed by thin layer of cuprous BTAH polymeric form. The surface analysis by scanning electron microscopy (SEM&EDS) and x-ray diffraction (XRD) demonstrated that the copper surface was covered mainly with cupreous oxide (Cu2O) layer. The cupreous chloride (CuCl) co-exists with BTAH，at the BTAH containing solutions.
[Key Word: impedance，inhibitor，copper，BTAH，chloride.]

並列關鍵字

impedance ； inhibitor ； copper ； BTAH ； chloride

參考文獻

Corrosion Science，42，259，(2000)

(9)，1545， (1996)

Sakurai，App. Surface Science ， 87/88，380，(1995)

Kaufman ， B. M. Rush，and G. S.Frankel， Electrochem. Soc.，

138 (8)，2253， (1991)