Abstract:By means of OM, EDS, SEM and TEM, the effect of microstructures of AA3003 aluminum alloy foils on specific capacitance was investigated . The results show that the specific capacitance of the cathode aluminum foils depends on the microstructures of the foils, including intermetallic compound (Mn,Fe)Al₆ and Al matrix, tangled dislocations in the regions adjacent to the intermetallic particles, and smaller and dispersed particles. Because the dislocation interaction with larger particles gives rise to high local lattice curvature in the matrix, which can be preferentially dissolved when etched, which results in serious remnant metal powders on the foil surface. Solid solution at 630℃, quenching in water and aging at 60℃ may increase the number of the second phase particles, and reduce the large particles, so that the capacitance of the cathode foils becomes higher and almost no powders remain on the surface of the foil. By means of aging after quenching, the precipitated particles and etch-pit density in the foil increase obviously, therefore the favourable microstructures can be produced to improve the specific capacitance of the foils.

Key words: AA3003 aluminum alloy; cathode foil; microstructure; specific capacitance