An Investigation on the Relationship Between Surface Roughness Parameters and Anticorrosion Performance of A Zinc Phosphate Conversion Coating

This study was carried out in order to investigate the relationship between surface topographical parameters and the anticorrosion performance of a phosphate conversion coating (pcc). for this purpose, steel plates were treated in phosphating baths with different concentrations of the accelerator, with and without the surface activation, creating surfaces with various surface textures. accordingly, electrochemical and roughness parameters of phosphate layers were obtained from polarization curves and atomic force microscopy (afm) images, respectively. the results evidenced that corrosion current density (icorr) has a noticeable correlation with roughness parameters, including mean depth of the lowest valleys (svm), mean of the maximum peak to valley heights (stm), skewness of the surface height distribution (ssk) and surface solidity factor (km = s_vm/s_tm ). in fact, samples with surface structures containing more deep valleys had lower corrosion current density, indicating that these valleys can act as pathways that facilitate the electrolyte penetration through the phosphate layer.

An investigation on the relationship between surface roughness parameters and anticorrosion performance of a zinc phosphate conversion coating

This study was carried out in order to investigate the relationship between surface topographical parameters and the anticorrosion performance of a Phosphate Conversion Coating (PCC). For this purpose, steel plates were treated in phosphating baths with different concentrations of the accelerator, with and without the surface activation, creating surfaces with various surface textures. Accordingly, electrochemical and roughness parameters of phosphate layers were obtained from polarization curves and Atomic Force Microscopy (AFM) images, respectively. The results evidenced that corrosion current density (icorr) has a noticeable correlation with roughness parameters, including mean depth of the lowest valleys (Svm), mean of the maximum peak to valley heights (Stm), skewness of the surface height distribution (Ssk) and surface solidity factor (Km = S_vm/S_tm ). In fact, samples with surface structures containing more deep valleys had lower corrosion current density, indicating that these valleys can act as pathways that facilitate the electrolyte penetration through the phosphate layer.