电沉积Zn预处理对高压阳极铝箔电解腐蚀行为的影响

恒定电流下在酸碱预处理后的铝箔表面电沉积微量Zn,得到电沉积改性预处理铝箔,对其进行直流电化学腐蚀。使用EDS能谱分析电沉积Zn铝箔表面元素;利用金相显微镜与扫描电镜从断面、表面观察样品铝箔腐蚀形貌;利用极化曲线、失重率、减薄率观测样品铝箔的腐蚀电位、腐蚀效果,研究不同预处理工艺对高压阳极铝箔电解腐蚀行为的影响。结果表明:电沉积Zn预处理后,由于沉积在铝箔表面的Zn和Al存在电位差,形成Al-Zn微电池促进铝箔腐蚀发孔,其腐蚀电位由酸碱预处理铝箔的-0.83 V下降到-0.87 V,铝箔腐蚀后隧道孔数量较多,分布更加均匀,减薄率下降,失重率上升,得到了比表面积更大的铝电解电容器用阳极腐蚀箔。

Effect of electrodeposited pretreatment on electrochemical corrosion behavior of anode aluminum foil

The trace Zn was electrodeposited on the surface of the aluminum foil after acid-base pretreatment under constant current,and the electrodeposited modified aluminum foil was obtained and subjected to DC etching.The surface elements of electrodeposited Zn aluminum foil were analyzed by EDS spectroscopy.The morphology of etched aluminum foil was observed from the cross section and surface by metallographic microscope and scanning electron microscope respectively.The free corrosion potential and electrochemical performance of aluminum foil were observed by polarization curve,weight loss rate and thinning rate.The effects of different pretreatment processes on the electrochemical corrosion behavior of aluminum foil were studied.The results show that after pretreatment of electrodepositing Zn,the potential difference between Zn and Al deposited on the surface of aluminum foil is formed,simultaneously,Al-Zn micro-batteries are formed to promote the etching of the aluminum foil.The free corrosion potential is reduced from-0.83 V of acid-base pretreated aluminum foil to-0.87 V.Compared to blank aluminum foil,the electrodeposited Znaluminum has the larger number and the more uniform distribution of tunnels after DC etched,at the same time,its thinning rate is decreased,the weight loss rate is increased.The aluminum foil for capacitors with larger specific surface area and specific capacitance can be obtained.