In-situ KFM observation of atmospheric corrosion on low alloy steel
Sea salt particles of 10 - 20ug/cm2 were attched on SM50B, 3%Cr and 3%Ni steel at 40% RH. After the specimens were kept at 85% RH for 1h, they were kept at 40% RH and the progress of corrosion was observed by KFM (80um X 80um). In the right image of the movie, bright part corresponds the negative potential part. Upper image shows the optical microscope image of observed part of SM50B. Thin liquid film of about 10 nm in thickness ( dark area in potential distribution image in upper image) was produced at high relative humidity once corrosion started. This thin liquid plays very important role to accerelate the atmospheric corrosion.
3%Cr
3%Ni