電泳沉積與其塗層之電化學特性研究

The study of electrophoretic deposition and the electrochemical properties of EPD layer

湯和益(Her-Yi Tang)

指導教授 ： 顏溪成

國立臺灣大學/工學院/化學工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.03094

摘要

本實驗分為四大部份：第一部份針對磷酸鈦膠體(磷酸鈦)水溶液之粒徑分佈與介面電位進行探討；第二部份針對於利用電鍍法於基材(304-不鏽鋼片)表面電鍍一層磷酸皮膜，並且探討磷酸鈦膠體濃度、電鍍溫度對於磷酸皮膜化之影響。同時針對磷酸皮膜試片進行以下電化學特性分析，電位與時間關係、電流與時間關係、極化曲線分析、交流阻抗分析。除此之外也利用化學法進行磷酸皮膜化成反應(基材:鍍鋅鐵片)，並且探討添加氧化劑(NaNO3與 NaF)影響，反應過程中也透過開環電量測，了解電位變化；第三部份針對第二部份所製備之磷酸皮膜試片進行電泳塗佈程序，並且探討塗層性質(塗料官能基、玻璃轉移溫度)。同時針對電泳塗層進行以下電化學特性分析，電位與時間關係、電流與時間關係、極化曲線量測、交流阻抗分析、開環電位量測；第四部份針對第二部份、第三部份之電泳塗層膜厚關係，建立動力學模型，透過電泳塗層之膜厚進行動力學分析，並且建立於成膜速率與電壓關係。
為了達到要求條件，分別為磷酸皮膜厚度約為2um，電泳塗層厚度為20um ，因此透過實驗找到最佳化條件進行，實驗結果發現當選用磷酸鈦膠體濃度為1%對基材(304-不鏽鋼)表面進行前處理，並且透過定電流密度-5mA/cm2，電鍍時間為10分鐘，溫度27oC，其磷酸皮膜厚度約為1.85 um，並且進行電泳塗佈程序，並且透過定電壓50V，於長方形電鍍槽(陰陽及距離5cm)中進行，電鍍時間為3分鐘，溫度27oC，並且烘烤溫度為80oC，電泳塗層厚度達到21um 。於實驗過程中也分別探討磷酸皮膜與電泳塗層之電化學特性，磷酸皮膜之腐蝕電位約為-1.12 V、阻抗大小約為600 Ohm-cm2。同時發現當電度磷酸皮膜之電流密度提高時，對於腐蝕電位也相對較負與腐蝕電流密度相對變大，且磷酸皮膜之鈍化層也會相對明顯；電泳塗層之腐蝕電位約為-0.98 V、阻抗大小約為1380 Ohm-cm2。

關鍵字

電泳沉積；磷酸皮膜腐蝕電位

並列摘要

In this study the phosphating and the electrophoretic deposition (EPD) of polymers on 304 stainess steel sheet and galvanized steel plates have been investigated.
The effect of titanium phosphate pretreatment on the phosphating electrochemically to the 304 stainless steel sheets and galvanized steel plates has also been studied. Frthermore, by potentialdynamic polarization, open circuit potential measurements and electrochemical impedance measuremets, the electrochemical characteristics of the phosphating and EPD layers can be understood and classified with 1.85 of phosphating layer prepared by the 1% titanium compound formulation and zinc phosphating at 5 mA/cm2 and 27oC for 10 minutes, the thickness of EPD layer at applied voltage of 50 V for 3 minutes in a rectangular cell of 5 cm electrode spacing is 21um . The thickness versus electrophoretic deposition time has also been found and a simple kinetics was proposed.
In the electrochemical properties test to EPD layer, the results show that electrochemical properties to EPD layer (at constant voltage of 50 V for 3 mins and at baking temperature 80oC for 30 mins) with corrosion potential, -0.98 V and coating resistance, 1380 Ohm-cm2 as increasing the baking temperature, improves the protection properties of the electrophoretic coating.
Finally, the OCP and EIS of EPD layers in 3.5 % NaCl solution were measured, and it has been found that the EPD films with 50 V/5 cm has better electrochemical characteristic.

並列關鍵字

Electrophoretic deposition ； phosphating corrosion potential

參考文獻

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