摘要
The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 electrolyte at 80 ℃. The pitting potential and self corrosion potential of A1 foil were measured with polarization curves （PC）. The potentiostatic current--time curve was recorded and the surface and cross section images of etched A1 foil were observed with SEM. The electrochemical impedance spectroscopy （EIS） of etched A1 foil and potential transient curves （PTC） during initial etching stage were measured. The results show the chemical pretreatments can activate A1 foil surface, facilitate the absorption, diffusion and migration of C1- onto the A1 foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched A1 foil.
将高压铝电解电容器用铝箔在40℃的0.5 mol/L H_3PO_4或40℃的0.125 mol/L NaOH溶液中进行浸泡预处理,再在80℃的1 mol/L HCl+2.5 mol/L H_2SO_4电解液中进行直流电解腐蚀。采用动电位极化法研究预处理对铝箔点蚀电位和腐蚀电位的影响;用恒电位极化法和扫描电镜(SEM)研究了预处理对铝箔表面亚稳孔萌生速率的影响;用SEM和交流阻抗(EIS)研究了预处理对腐蚀箔表面、横截面形貌及电化学行为的影响;用A/D模块采集了电解腐蚀初期槽电压—时间瞬时曲线。结果表明:预处理促进了铝箔表面活化,有助于电蚀时Cl^-在铝箔表面的吸附、扩散和迁移,提高亚稳蚀孔萌生率及稳定蚀孔和隧道微孔的密度,从而导致腐蚀箔比表面积和比电容增加。
基金
Project supported by University New Materials Disciplines Constructions Program of Beijing Region,China
Project(51172102/E020801) supported by the National Natural Science Foundation of China
