On the quantitative assessment of corrosion damages of aluminum at the early stages using confocal laser scanning microscopy

Despite being widely used in such industries as chemical, aviation and food ones, aluminum and its alloys are known to be prone to localized corrosion, and this remains a problem to be solved, especially when it comes to pitting corrosion. Therefore, there is a necessity to detect traces of corrosion at the earliest stages and to quantify the extent of corrosion damage. The simplest solution for assessing the overall corrosion rate is to use the gravimetric method, which, however, does not provide information for assessment of localized corrosion. This paper is devoted to the consideration of the possibilities of using the method of confocal laser scanning microscopy (CLSM) for assessing corrosion resistance using high-purity aluminum. The CLSM method, due to its high resolution (especially along the vertical axis), enables to obtain quantitative data on the volume of corroded metal, determine the depth of corrosion damage including building their profilograms, and analyze the morphology of the surface damaged by corrosion. Owing to the high sensitivity of the CLSM method, corrosion losses were detected within 21 days, contrary to the standard gravimetric method, which failed to determine the loss of metal even after 160 days of corrosion testing.