Abstract

White light interferometry was applied to obtain the rate change of an oxide film growth of aluminum samples during the anodization in aqueous solutions The thickness d of the oxide film was determined by Fabry-Perot i e white light interferometry In other words for the first time an electromagnetic i e Fabry-Perot method was utilized to obtain the rate change of the oxide film growth of aluminum samples rather than the electronic i e direct current DC or alternating current AC methods as a function of the time t of the anodization processes Therefore the abrupt rate change of the d d dt was called anodization-emission spectroscopy The anodization process of the aluminum samples was carried out by the DC method in different sulphuric acid concentrations 0 0 2 4 6 8 10 H2SO4 at room temperature In the meantime the Fabry-Perot interferometry was used to determine the difference between d of two subsequent values d d as a function of the elapsed time dt of the DC experiment for the aluminum samples in H2SO4 solutions The Fabry-Perot interferometry was based on a fiber-optic sensor to make real time-white light interferometry possible at the aluminum surfaces in the acid solutions Also an abrupt rate change of the d d dt of the oxide film of the aluminum in 2 0 4 0 6 0 8 8 10 0 H2SO4 and in deionized water 0 0 H2SO4 was observed to occur once between 10 to 20 minutes Then the d d dt of the oxide film was recorded around zero between 20 to 30 minutes Eventually the d d dt of the oxide film was gradually increased during the remaining elapsed time of the experiment