Research Of Preparation Process For Anode Foil Of Supervoltage Aluminum Electrolytic Capacitor

Aluminum electrolytic capacitor is a electronic component which is difficult to integration circuit, improve the specific capacitance is always its research direction. In recent years, ultra high voltage aluminum electrolytic capacitor becomes more and more urgent demand,ultra high voltage anode foil is the key material for preparation of ultra high voltage aluminum electrolytic capacitors, which determines the electrical properties of aluminum capacitor capacitance.This paper has researched the influence of corrosion conditions and corrosion inhibitor on the capacitance of anode foil for ultra high voltage(700Vfe) aluminum electrolytic capacitor, which based on the specific capacitance as the evaluation index. The effect of composite oxide film on improving capacitance of ultra high voltage anode foil have been tried.The influence factor of initial etching such as temperature,current density,corrosion time and concentration of Al3+were investigated by orthogonal experiment.The orthogonal result show that initial etching temperature was the major factor to supervoltage anode foil capacitance, current density and corrosion time take the second place,the concentration of Al3+ was the minor influence factor.The effect of initial etching process on ultra high voltage anode foil capacitance and withstand voltage has been research. The best condition for anode foil which used to Vfe=700V are that:[Cl-]/[SO42-]=1mol/L/3mol/L,concentration of Al3+ is 0.2 mol/L,corrosion temperature is 75℃,current density is 0.40 A/cm2,and corrosion time is 120s; Under the optimal initial etching process conditions, then increasing tunnel diameter in 1 mol/LHNO3 slution,which temperature is 75℃,current density is 0.1 A/cm2, and time is 500 s,after two level formed to 700 V, the withstand voltage is 668 V, the capacitance reach to 0.48μF/cm2.The influence of corrosion inhibitor of CTAB、 EDTA、PEG 4000 on specific capacitance of super high voltage anode foil has been studied. Results show that, three kinds of corrosion inhibitor can effectively improve specific capacitance of ultra high voltage anode foil, but the amount should be controlled within a proper range,The optimal concentration of three kinds corrosion inhibitors is: CTAB is 3 g/L, EDTA is 2.5 g/L,PEG4000 is 1.25g/L.The composite oxide film Ca Cu3Ti4O12 has been preparation by sol-sel. Influence of dipping times and dipping time on ultra high voltage anode foil capacitance and withstand voltage has been studied by czochralski. The sol immersion the tunnel will take some time, After filled the tunnel with immersion time prolonged the attachment will not be increased, short dipping time can not improve capacitance significantly, too long dipping time will not continue to increase capacitance, the study show that the time of dipping should be controlled at 40 s.The influence of Al2O3-Ca Cu3Ti4O12 composite oxide film on the capacitance and withsand voltage of supervoltage anode foil has been studied by anodic electrodeposition method.It is found that the deposition time affect the amount of deposition, with the increase of deposition time, the amout of deposition is increasing. Tunle will be blocked if deposition time is too long,the specific capacitance is not improved, the optimum deposition time should be controlled at about 15 min.