Anodic oxidization of Al-Y amorphous alloy ribbons and their capacitive properties

Blackish amorphous aluminium oxide film on AlY₁₀ amorphous alloy ribbons was prepared by anodic polarization process in H₂SO₄ solutions, showing electric storage on uneven surfaces with a convexity of 18 nm in diameter. The longest discharging time was obtained by current ratio (I₂/I₁) of 0.4 at 16 V and 5 mass% H₂SO₄. The discharging time increases and decreases with increasing charging time and charging current, and then saturates after around 100 s and 1 μA, respectively. The resulting film shows a vertical line after Warburg region in a Nyquist diagram, rapid increases in the imaginary impedance, and a phase angle of −90° at 1 mHz in the Bode diagram, demonstrating evidence for use in an electric distributed constant circuit. The film indicates a switching effect for both positive (∼+8.6 eV) and negative (∼-11.2 eV) potentials.