Abstract: The cubic texture of the annealed high purity aluminum foils with trace Ga used for the anode of high voltage electrolytic capacitors was quantitatively characterized by Xray diffractometer (XRD). The microstructures of their hotrolled plates and final annealed foils were observed by optical microscope(OM) and scanning electron microscope (SEM). The corrosion structures of the etched foils were quantitatively analyzed with image analysis software. Based on the above experiments the effects of the mass fraction of trace Ga on the microstructures and the corrosion structure as well as the specific capacitance were investigated. The results showed that with the mass fraction of Ga increasing from 05×10-6 to 116×10-6， the volume fraction of cubic texture in the foils decreased slightly， but the specific capacitance of the foils measured at 520V increased from 0662μF/cm2 to 0706μF/cm2. Further increasing the mass fraction of Ga to 214×10-6 did not affect the microstructure and the fraction of the cubic texture， but the specific capacitance dropped to 0693μF/cm2. Adding trace Ga promoted the electrochemical pitting and resulted in the enlargement of the specific surface area of the foil and the improvement of the specific capacitance. However when the mass fraction of Ga was higher than 116×10-6， obvious pit merging occurred， the specific surface area of the foil reduced and the specific capacitance decreased.

Key words: electrolytic capacitor, high voltage aluminum foil, trace Ga, specific capacitance, cubic texture