Effect of Additive DCTA on Electrochemical Tunnel Etching of Aluminum Foil

The effect of additive DCTA (1,2-diaminocyclohexane-tetraacetic acid) to HCl + H2SO4 solution on electrochemical tunnel etching behavior of aluminum foil was investigated. The results show that DCTA can activate Al foil surface by decreasing the self-corrosion potential and breakdown potential, which may be attributed to that DCTA forms chelate with dissolved Al3+, thus suppressing the oxide film formation. The tunnel density and effective tunnel number as well as uniformity of tunnel length of etching foil can be increased after DCTA addition. Furthermore, the specific capacitance of etching foil can be enhanced with trace addition of DCTA.