Investigation on steel materials of pits of corrosion with image processing

Corrosion is a cause of losing metallic properties of metals after making electrochemical and chemical reactions with their society. Pitting corrosion is corrosion case which occurs pits on metal surface in the smallest area. Pits mostly can not be seen with eyes due to its too small. Pitting corrosion is the most dangerous corrosion type. Although small lost of material, components can be damaged in small time. Inside of pits are usually full with corrosion residuals. For this reason, it is extreme difficult to determination of number of pits as well as its depth.Digital image processing profits by images properties and provides to analyze. The main program used in analysis is Matlab program.In this study, hole formed by drilling were created with different diameter and deepness on steel material. Photograph of these holes were get by scan electron microscope. After that, the depth of holes was found to analyses in pixel size with help of matlab program. Steel specimens were hold in acidic solution for formation of special pits. After getting the photograph of pits with scan electron microscope, these were characterized by means of depth values using matlab program. Measured depths on the specimens and calculated depths values using image processing have been compared. As a result of examination, pith depths can be determined with a maximum 6,5% relative error.