No abstract

This work presents how performance of a simple Michelson interferometric configuration, allows monitoring of oxide layers growing in aluminium structures during preliminary states of oxidation processes in aqueous solutions, without any physical contact with the sample. The alternative experimental arrangement introduce a more simple alignment compared with preliminary proposals 1 , and the obtained interferograms offer a qualitative and quantitative interpretation of important physical parameters related to specified corrosion processes. Finally, a potential improvement in order to obtain monitoring of samples through turbid solutions is discussed.

No abstract

A brief investigation is presented in an electrochemical corrosion cell consisting of 99.5% aluminum sample immersed in 3% NaCl and hydrocarbon-chloride solution emulsion, which reaction processes were optically monitored using Michelson interferometry. An image processing method applied on obtained interferograms allowed to calculate oxide corrosion layer thickness formed over the metal surface. Additionally a theoretical model consisting of a two bi-dimensional difference equation system is proposed, in order to explain evolution of optical interference pattern maxima observed as a function of time for corrosion process, and also to establish a growth-competition model for the maxima fringes evolution and consequently for the oxide layer and corrosion system dynamics. Bifurcation diagrams showing equation system solution regions were additionally obtained based on the nonlinear dynamic behavior of corrosion processes showing chaotic dynamics.

This work presents the assessment of the dynamics of electrochemical corrosion of aluminium through Michelson´s optical interferometry measurements. Data were analysed using a new analysis method named Recurrence Plots (RP). This method allows the assessment of the dynamics of the pitting corrosion process of aluminium in chloride solution. After electrochemical potentiodynamic polarization, the curve characterizing the system corrosion regions was obtained. Interferograms for different regions (potentials) under potentiostatic control were registered, and digitally transformed. The analysis of these optical variableseries were conducted using a recurrence plot (RP) and quantification analysis (RQA). From the analysis it was determined the percent recurrence (%R), the percent determinism (%D) and the information Entropy for different electrochemical potentials. These parameters increased with polarization potential defining the different corrosion conditions of the metal from the active, passive pre-pitting and pitting regions within the polarization curve. From the interferometric measurements and RP analysis, it was possible to identify the different corrosion conditions and establish that pitting corrosion induced a more deterministic dynamics on the electrochemical process.