Method for Fast Quantification of Pitting Using 3D Surface Parameters Generated with Infinite Focus Microscope

Empirical correlations that enable fast estimation of maximum and average pit depths and pitted area percentage from the standard 3D surface parameters obtainable with infinite focus microscopy were established in this study. Carbon steel coupons pitted by the sulfate-reducing bacterium Desulfovibrio vulgaris were used as the specimens. The maximum and average pit depths and the pitted area percentage were first determined from laborious measurements of individually manually identified pits on the specimens and then used as the basis for developing the correlations. A four-phase diagram, with average pit depth as the y-axis and pitted area percentage as the x-axis, was proposed as an effective visual tool to categorize the varying pitting and risk patterns. The study results afford more effective, quantitative characterization of pitting corrosion.