Impedance spectroscopy of the process of hard anodizing of aluminum alloys

This article discusses an in situ method for the diagnostics of the hard anodizing process based on impedance spectroscopy allowing the coating thickness during treatment to be estimated. The experimental results are given for the hard anodizing of aluminum alloys used in the aircraft industry. Parameters of an equivalent circuit of the electrolyzer were specified and the regularities of their evolution were established. A diagnostic model was proposed and its efficiency was demonstrated for an industrial serial production.