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

Abstract

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.