Influence of Surface Roughness of Galvanized Steel Sheet on Self-lubricated Coating

Three different thicknesses of self-lubricated coatings were prepared on galvanized steel sheets with different surface roughness (Ra). Performances of the coatings were evaluated by various laboratory tests. Scanning electron microscopy (SEM), atomic force microscope (AFM), neutral salt spraying test (NSST), reciprocating friction and wear test were taken in order to characterize the coatings. Results show that the self-lubricated coating has good corrosion resistance and lubricating property. In 0.857—1.629 μm of Ra value, the relationship between friction coefficients of the self-lubricated steel sheets and the surface roughness of the galvanized steel sheets likes a parabolic curve, and has a peak value of friction coefficient in certain range of Ra. Affected by the hereditary surface topography of the galvanized steel sheet, dents on the surface of self-lubricated steel become deeper and larger with the increase of the surface roughness of the galvanized steel sheets. The influence of the surface roughness of the galvanized steel sheet on the corrosion resistance of the self-lubricated coating steel is similar to that on friction coefficient of self-lubricated coatings, like a parabolic curve.