Effect of cerium addition on microstructure and texture of aluminum foil for electrolytic capacitors

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 annealed. The results showed that addition of cerium contributed to higher <100> texture and higher etch pit density as well. Moreover, the distribution of etch tunnels was more uniform compared with that without cerium addition. Perfect specific surface area was obtained with 0.0074% addition of cerium.