Measurement of the double layer-capacitance of aluminium samples by holographic interferometry

In the present investigation, holographic interferometry was utilized for the first time to measure the double layer-capacitance of aluminium samples during the initial stage of anodization processes in aqueous solution without any physical contact. The anodization process (oxidation) of the aluminium samples was carried out chemically in different acid concentrations (0.5-3.125 % H2SO4) at room temperature. In the mean time, a method of holographic interferometric was used to measure the thickness of anodization (oxide film) of the aluminium samples in aqueous solutions. A long with the holographic measurement, a mathematical model was derived in order to correlate the duoble layer-capacitance of the aluminium samples in solutions to the thickness of the oxide film of the aluminium samples which forms due to the chemical oxidation. The thickness of the oxide film of the aluminium samples was measured by the real time-holographic interferometry . Consequently, holographic interferometric is found very useful) for surface finish industries especially for monitoring the early stage of anodization processes of metals , in which the thickness of the anodized film can be measured as well as the duoble layer-capacitance of the aluminium samples can be determined during the anodization processes.