Analysis on Cross-sectional Image and Phase of Galvannealed Coating with SEM

A kind of SEM cross-sectional image and phase analysis method for galvannealed coating was introduced in detail,which was based on normal metallographic method and helped by scanning electron microscope to get cross-sectional coating morphologies thereby to qualitatively analyze whether each Zn-Fe alloy phase formed or not and its quantity,including metallographic sample preparation,grinding,polishing,etching,and SEM cross-sectional image getting. In addition,the effects of etchant were also studied and it was found that the SEM cross-sectional image of the galvannealed coating etched by chromic acid,sodium sulfate,pickling inhibitor and water solution was comparatively perfect.