Investigations On The Technical Processes And Cube Texture In Anode Aluminum Foil

Electrolytic capacitor is one of the three basic electronic components, capacitor anode aluminum foil is the key material for high quality electrolytic capacitors. In order to develop domestic capacitor anode aluminum foil and to reduce the import of high voltage electrolytic capacitors, this thesis worked on the evolution of cube texture and making techniques of anode aluminum foil.Current process and research status quo of anode aluminum foil for high voltage electrolytic capacitors was summarized firstly in this paper, including the influence of chemical composition such as Fe Si Cu on the properties of anode aluminum foil, the influence of microstructures such as grain size, dislocation density, crystal orientation on specific capacitance of anode aluminum foil. Relating to practical processes, the paper analyzed the technologic status quo of homogenizing, hot rolling, preparing anneal, additional anneal, additional rolling deformation and last anneal, and the rule and mechanism research development of their effects on cube texture ratio in aluminum foil after last anneal. From the summary of hot rolling processes, the effect of original orientation and status of Fe, Si impurities were taken as important research objects. According to above research and technologic status quo, the total project focused on aluminum foils with low Fe, Si impurity and high Fe, Si impurity respectivelyThe paper introduced the analysis experiment of micro-texture, stated the technological principle of EBSD orientation image, and introduced the LEO 1530 scanning electronic microscope and its software as well as some new techniques. In order to achieve quick test for industrial texture, and especially to measure cube texture quantitatively, by means of foreign references related to etch pit shape in silicon steel, the method of industrial texture quick test for high purity aluminum was developed by this paper. The test method and skill of etch pit experiments were also summarized.The paper systematically researched the processing and the cube texture of Wu aluminum (high purity aluminum produced by Urumchi, China), emphasized the relationship between technological processes and cube texture of Wu aluminum containing low Fe, Si impurity. By tests of preparing anneal, cold rolling, last anneal and quantitative measurement of cube texture for finished product, the effect rule of hot finish rolling temperature, preparing anneal temperature, last anneal technique on the cube texture ratio was obtained. By observation of grain shape with positive electrode oxidingfilm, microstructure under SEM, precipitation distribution and microstructure under TEM, as well as other test methods, the rules of cube texture development and the main factors effecting cube texture ratio in Wu aluminum were analyzed. It was suggested that the cube texture ratio in the finished product of high purity anode foil with low Fe, Si content depended on the following: the original ratio of (001) grains, amount of S orientation, the effect of precipitation on recrystallization, the status of Fe, Si in aluminum. The development of cube texture in Wu aluminum and its effecting factors were roundly analyzed, which could provide reference to the production of high purity anode aluminum foil.The relationship between the processing and the cube texture of Mei aluminum (American high purity aluminum) containing high Fe, Si impurity was studied too in the paper. With quantitative measurement of cube texture in finished products, the effects of preparing anneal temperatures, additional partial recrystallization anneal temperatures, deformation rates of additional cold rolling and different processes for finished product anneal on the cube texture ratio were studied. The process variables were optimized to produce anode foil with high purity aluminum containing more Fe and Si content, and the development character of cube texture during technological process of Mei aluminum was analyzed and discussed.On the basis of above experiments, the paper studied the developmen...