Anode foil of aluminum electrolytic capacitor,which requires large surface area for high capacitance,were prepared by rolling,annealing and electrochemical etching.Effects of cerium addition on the capacitance of alum...Anode foil of aluminum electrolytic capacitor,which requires large surface area for high capacitance,were prepared by rolling,annealing and electrochemical etching.Effects of cerium addition on the capacitance of aluminum electrolytic capacitors were investigated.Microstructure of the aluminum foil surface was observed by optical microscopy(OM) and scanning electron microscopy(SEM).Electron back scattered diffraction(EBSD) was also employed to reveal texture evolvement of cold-rolled aluminum foil after ann...展开更多
The evolution of recrystallization textures in high voltage aluminum capacitor foils which are produced with a high level of cold reduction was tracked by analysis of microstructure and crystallographic texture. The r...The evolution of recrystallization textures in high voltage aluminum capacitor foils which are produced with a high level of cold reduction was tracked by analysis of microstructure and crystallographic texture. The results show that the deformation textures are mainly composed of S orientation, Cu orientation and a little B s orientation. During the low temperature stages of final annealing, the iron precipitates first along the sub grain boundaries, and the Fe concentration in the matrix becomes low. Then, the cube grains nucleate preferably into the sub grains. At high temperature stages, the cube nuclei can grow preferably because of their 40°<111> orientation relationship to the S orientation, the main component of the rolling texture. Finally, the cube texture is sharply strong and the R orientation is very weak in the foils.展开更多
The distribution of microelement Fe, Si, Cu and Mg in the surface layer of aluminum foil annealed at 300℃ and 500℃ were determined by secondary ion mass spectrometer. The corrosion structure produced by electrochemi...The distribution of microelement Fe, Si, Cu and Mg in the surface layer of aluminum foil annealed at 300℃ and 500℃ were determined by secondary ion mass spectrometer. The corrosion structure produced by electrochemical etching was also observed. It was found that the Mg concentration at external surface was increased exponentially over the fourth degree and promoted by higher annealing temperature, which will increase the number of corrosion pits inside the large grains, and therefore the specific capacity of the foils for electrolytic capacitors. The similar effects of microelement Fe, Si and Cu were not so strong.展开更多
The cube texture and the surface corrosion structure of aluminum anode foil for high voltage electrolytic capacitor containing trace Sn were investigated based on quantitative texture analysis and microstructure obser...The cube texture and the surface corrosion structure of aluminum anode foil for high voltage electrolytic capacitor containing trace Sn were investigated based on quantitative texture analysis and microstructure observation under SEM. High volume fraction of cube texture over 95% and obviously higher specific capacity are obtained in the foils with less than 0.002% Sn. It is indicated that the corrosion behavior of trace Sn on aluminum surface is similar with that of Pb. Higher content of Sn over 0.002% reduces the cube texture component and therefore the specific capacity. Sn, as an eco-friendly microelement, can be applied to replace Pb in improving the homogenous pitting behaviors of high voltage aluminum foils.展开更多
The effect of trace Sn on the pitting morphology of high voltage anode aluminum foils was investigated. The distributions of microelement Sn, Fe, Si, Cu and Mg in the surface layer of aluminum foils with different Sn ...The effect of trace Sn on the pitting morphology of high voltage anode aluminum foils was investigated. The distributions of microelement Sn, Fe, Si, Cu and Mg in the surface layer of aluminum foils with different Sn content were determined by using a secondary ion mass spectrometer. It was found that the micro-alloyed Sn is enriched at the external surface. The mechanism of pitting behavior of trace Sn on aluminum surface is similar with that of lead. Enrichment of Sn in the surface layer provides large numbers of sites for initiation of pitting corrosion, while pitting sites appeared relatively inhomogenously in the foils without Sn. Sn, as an eco-friendly microelement, can be applied to replace Pb in improving the homogenous pitting behaviors of high voltage aluminum foils, in which the volume fraction of cube texture is not reduced.展开更多
The morphology of etched aluminum foil was observed using scanning electron microscopy, which led to the establishment of a cylindrical model and two merged models, considering the fixed weight loss of etching. The ma...The morphology of etched aluminum foil was observed using scanning electron microscopy, which led to the establishment of a cylindrical model and two merged models, considering the fixed weight loss of etching. The maximum of specific capacitance and the cor- responding optimum values for tunnel sizes at various anodization voltages were predicted. The increased size distribution and taper of tun- nels were demonstrated to decrease the specific capacitance, whereas the addition of polymeric additive into the ttmnel widening solution was demonstrated to increase the capacitance. The formation of merged tunnels on the etched aluminum surface, irrespective of the presence of row-merged tunnels or cluster-merged tunnels, resulted in a dramatic decrease in the specific capacitance. It is concluded that, enhancing the uniformity of turmel size and distribution and avoiding the formation of merged tunnels are the effective approach to achieving the higher capacitance for the tunnel etched and formed aluminum foil.展开更多
The limiting length of tunnels, llim, of Al foil electro-etched in HCl-H2SO4 solution and the corresponding anodic polarization curves in the same solution were measured. It is found that there is a dependence of llim...The limiting length of tunnels, llim, of Al foil electro-etched in HCl-H2SO4 solution and the corresponding anodic polarization curves in the same solution were measured. It is found that there is a dependence of llim on the potential difference, △φ, between the pitting potential, φpit, and the corrosion potential, φcorr, of Al foil, when the temperature and H2SO4 concentration of HCl-H2SO4 electrolyte are changed. The dynamic equation on the tunnel growing and the linear equation between llim and △φ were deduced by analyzing the relationship among the over-potential on Al foil surface, the transport over-potential in tunnel solution and the over-potential at tunnel tip during the electro-etching. The results show that the growing velocity of tunnels decreases with their extending in length and the changing trend of llim can be judged by measuring △φ, which supplies a convenient access to explore new kinds of etchants.展开更多
基金supported by the Inner Mongolia Important Science & Technology Project (20071911)Inner Mongolia Technology Research & Development Project
文摘Anode foil of aluminum electrolytic capacitor,which requires large surface area for high capacitance,were prepared by rolling,annealing and electrochemical etching.Effects of cerium addition on the capacitance of aluminum electrolytic capacitors were investigated.Microstructure of the aluminum foil surface was observed by optical microscopy(OM) and scanning electron microscopy(SEM).Electron back scattered diffraction(EBSD) was also employed to reveal texture evolvement of cold-rolled aluminum foil after ann...
文摘The evolution of recrystallization textures in high voltage aluminum capacitor foils which are produced with a high level of cold reduction was tracked by analysis of microstructure and crystallographic texture. The results show that the deformation textures are mainly composed of S orientation, Cu orientation and a little B s orientation. During the low temperature stages of final annealing, the iron precipitates first along the sub grain boundaries, and the Fe concentration in the matrix becomes low. Then, the cube grains nucleate preferably into the sub grains. At high temperature stages, the cube nuclei can grow preferably because of their 40°<111> orientation relationship to the S orientation, the main component of the rolling texture. Finally, the cube texture is sharply strong and the R orientation is very weak in the foils.
基金The authors would like to acknowledge the financial supports from the National High Technology Research and Development Program of China(863 program,grant No.2003AA32X170)the Doctoral Foundation of the Eduction Ministry of China(grant No.20040008010).
文摘The distribution of microelement Fe, Si, Cu and Mg in the surface layer of aluminum foil annealed at 300℃ and 500℃ were determined by secondary ion mass spectrometer. The corrosion structure produced by electrochemical etching was also observed. It was found that the Mg concentration at external surface was increased exponentially over the fourth degree and promoted by higher annealing temperature, which will increase the number of corrosion pits inside the large grains, and therefore the specific capacity of the foils for electrolytic capacitors. The similar effects of microelement Fe, Si and Cu were not so strong.
基金Project(50571020) supported by the National Natural Science Foundation of ChinaProject(20040008010) supported by the Doctoral Foundation of the Education Ministry of China
文摘The cube texture and the surface corrosion structure of aluminum anode foil for high voltage electrolytic capacitor containing trace Sn were investigated based on quantitative texture analysis and microstructure observation under SEM. High volume fraction of cube texture over 95% and obviously higher specific capacity are obtained in the foils with less than 0.002% Sn. It is indicated that the corrosion behavior of trace Sn on aluminum surface is similar with that of Pb. Higher content of Sn over 0.002% reduces the cube texture component and therefore the specific capacity. Sn, as an eco-friendly microelement, can be applied to replace Pb in improving the homogenous pitting behaviors of high voltage aluminum foils.
基金the National Natural Science Foundation of China(Grant No.50571020)the Doctoral Foundation of the Education Ministry of China(Grant No.20040008010).
文摘The effect of trace Sn on the pitting morphology of high voltage anode aluminum foils was investigated. The distributions of microelement Sn, Fe, Si, Cu and Mg in the surface layer of aluminum foils with different Sn content were determined by using a secondary ion mass spectrometer. It was found that the micro-alloyed Sn is enriched at the external surface. The mechanism of pitting behavior of trace Sn on aluminum surface is similar with that of lead. Enrichment of Sn in the surface layer provides large numbers of sites for initiation of pitting corrosion, while pitting sites appeared relatively inhomogenously in the foils without Sn. Sn, as an eco-friendly microelement, can be applied to replace Pb in improving the homogenous pitting behaviors of high voltage aluminum foils, in which the volume fraction of cube texture is not reduced.
基金financially supported by the Research Project of Guangxi Zhuang Autonomous Region,China(Nos.1346011-7 and 1298019-11)the financial support from the Guangxi Hezhou Guidong Electronics Technology Co.,Ltd
文摘The morphology of etched aluminum foil was observed using scanning electron microscopy, which led to the establishment of a cylindrical model and two merged models, considering the fixed weight loss of etching. The maximum of specific capacitance and the cor- responding optimum values for tunnel sizes at various anodization voltages were predicted. The increased size distribution and taper of tun- nels were demonstrated to decrease the specific capacitance, whereas the addition of polymeric additive into the ttmnel widening solution was demonstrated to increase the capacitance. The formation of merged tunnels on the etched aluminum surface, irrespective of the presence of row-merged tunnels or cluster-merged tunnels, resulted in a dramatic decrease in the specific capacitance. It is concluded that, enhancing the uniformity of turmel size and distribution and avoiding the formation of merged tunnels are the effective approach to achieving the higher capacitance for the tunnel etched and formed aluminum foil.
基金Project supported by University New Materials Disciplines Construction Program of Beijing, China
文摘The limiting length of tunnels, llim, of Al foil electro-etched in HCl-H2SO4 solution and the corresponding anodic polarization curves in the same solution were measured. It is found that there is a dependence of llim on the potential difference, △φ, between the pitting potential, φpit, and the corrosion potential, φcorr, of Al foil, when the temperature and H2SO4 concentration of HCl-H2SO4 electrolyte are changed. The dynamic equation on the tunnel growing and the linear equation between llim and △φ were deduced by analyzing the relationship among the over-potential on Al foil surface, the transport over-potential in tunnel solution and the over-potential at tunnel tip during the electro-etching. The results show that the growing velocity of tunnels decreases with their extending in length and the changing trend of llim can be judged by measuring △φ, which supplies a convenient access to explore new kinds of etchants.
