(北京科技大學(xué) 北京市腐蝕、磨蝕與表面技術(shù)重點(diǎn)實(shí)驗(yàn)室，北京100083)
摘 要: 研究發(fā)孔鋁箔在鹽酸和硝酸溶液中的陽極極化行為與擴(kuò)孔特性的關(guān)系。陽極擴(kuò)孔的基本條件是將發(fā)孔箔的內(nèi)、外表面都控制在鈍化狀態(tài)下。在鹽酸溶液中，陽極極化時(shí)存在點(diǎn)蝕電位和一個(gè)較小的鈍化電位區(qū)，當(dāng)擴(kuò)孔施加的電流密度大于臨界點(diǎn)蝕電流密度時(shí)，鋁箔表面發(fā)生二次發(fā)孔，導(dǎo)致形成孔蝕族與并孔，腐蝕箔厚度減薄，比電容顯著降低。在硝酸溶液中，陽極極化時(shí)存在一個(gè)寬闊的鈍化電位區(qū)，因此硝酸擴(kuò)孔比鹽酸擴(kuò)孔容易控制，不會(huì)發(fā)生二次發(fā)孔。提高鹽酸或硝酸濃度與溫度均可以增大最大維鈍電流密度，即增大擴(kuò)孔的最大電流密度，提高擴(kuò)孔的生產(chǎn)效率。
關(guān)鍵字: 鋁箔；電解電容器；電蝕；極化曲線；孔蝕
（Beijing Key Laboratory for Corrosion, Erosion and Surface Technology, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The relationship between anodic polarization of etched Al foils and performance in increasing tunnel diameter in both HCl and HNO3 etchants was studied. The essential condition to increase tunnel diameter by anodic electrolysis is to control both interior and exterior surfaces of tunnels under passivation. The anodic polarization curves in HCl solution are characteristic of a pitting potential and a narrow passivation range. When the etching current in HCl solution is above the critical pitting current density, pitting corrosion will occur again, leading to tunnel-clusters and tunnel-mergers and decrease in thickness and special capacitance of Al foil. The anodic polarization curves in HNO3 solution are characteristic of a wide passivation range. It is more convenient to control tunnel widening in HNO3 solution than in HCl solution, without pitting again. Increasing the temperature and concentration of both solutions can enhance the maximum passivation current density for tunnel widening and production efficiency.
Key words: aluminum foil; electrolytic capacitor; electro-etching; polarization curves; pitting
