Self-ordered aluminum anodizing in phosphonoacetic acid and its structural coloration

Abstract

Ordered anodic porous alumina with large-scale periodicity was fabricated via phosphonoacetic acid anodizing. Aluminum specimens were anodized in a 0.1-0.9Mphosphonoacetic acid solution under various electrochemical operating conditions, and optimum anodizing at 205-225 V exhibited self-ordering growth of the porous alumina. These self-ordering voltages during phosphonoacetic acid anodizing filled an undiscovered vacant region in the linear relationship between the self-ordering voltage and the cell diameter. The nanostructured aluminum surface formed via self-ordering phosphonoacetic acid anodizing produced a bright structural coloration with a visible light wavelength of 500-700 nm, which is useful for optical nanoapplications.