Possibilities and limitations of digital speckle pattern interferometry in the analysis of corrosion processes in metallic materials

摘要

Digital speckle pattern interferometry (DSPI) has been applied to evaluate corrosion levels in the surface of a copper electrode while immersed in a 0.1M CuSO_4 solution. The corrosion process has been induced by applying an electrical current between two such metallic Cu electrodes. The corrosion process can induce changes not only in the electrode surface but also in the solution refractive index. Different DSPI experimental setups have been proposed for evaluating both contributions and removing the refractive index contribution. Surface changes on the electrode as measured by DSPI have been compared with topography data obtained by confocal microscopy. Confocal microscopy data have shown that the corrosion process occurs at small scales. The possibilities and limitations of DSPI for measuring such non-uniform corrosion processes have been analyzed.