(北京科技大學(xué) 材料學(xué)系，北京 100083)
摘 要: 觀察了經(jīng)300 ℃退火并分別快冷和慢冷的鋁箔表面的電化學(xué)腐蝕結(jié)構(gòu)。 利用二次離子質(zhì)譜儀檢測了鋁箔表面區(qū)域Fe、 Si、 Cu、 Mg等微量元素的分布。 結(jié)果顯示: Mg在鋁箔外表面的富集高于鋁箔內(nèi)部4個數(shù)量級， Fe、 Si的富集程度約高2個數(shù)量級， 而Cu則不足1個數(shù)量級。 退火后慢速冷卻會造成富集于表面的微量元素偏聚于晶界和位錯周圍， 從而會加重腐蝕結(jié)構(gòu)的不均勻性并降低鋁箔的比電容。
關(guān)鍵字: 鋁箔； 微量原子； 腐蝕； 微觀結(jié)構(gòu)； 電解電容器
FENG Hui-ping, YU Yong-ning
（ Department of Materials, University of Science and Technology Beijing, Beijing 100083, China）
Abstract: The surface corrosion structures of aluminum foils, which were annealed at 300 ℃ followed by rapid and slow cooling respectively, were observed after electrochemical etching. The distributions of microelements Fe, Si, Cu and Mg in the surface layer were also determined by secondary ion mass spectrometer. It is found that the Mg content at external surface is increased exponentially over the four orders of magnitude in comparison with that in center layer. The corresponding contents of Fe and Si are increased about two orders of magnitude; while the content of Cu is increased lower than one order of magnitude. The slow cooling after annealing will lead to stronger segregation of microelements around the grain boundaries and dislocations in the surface, which aggravates the inhomogeneity of corrosion structure and results in low specific capacity.
Key words: aluminum foil; microelement; corrosion; microstructure; electrolytic capacitor
