(北京科技大学 北京市腐蚀、磨蚀与表面技术重点实验室，北京100083)
摘 要: 研究发孔铝箔在盐酸和硝酸溶液中的阳极极化行为与扩孔特性的关系。阳极扩孔的基本条件是将发孔箔的内、外表面都控制在钝化状态下。在盐酸溶液中，阳极极化时存在点蚀电位和一个较小的钝化电位区，当扩孔施加的电流密度大于临界点蚀电流密度时，铝箔表面发生二次发孔，导致形成孔蚀族与并孔，腐蚀箔厚度减薄，比电容显著降低。在硝酸溶液中，阳极极化时存在一个宽阔的钝化电位区，因此硝酸扩孔比盐酸扩孔容易控制，不会发生二次发孔。提高盐酸或硝酸浓度与温度均可以增大最大维钝电流密度，即增大扩孔的最大电流密度，提高扩孔的生产效率。
关键字: 铝箔；电解电容器；电蚀；极化曲线；孔蚀
（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
