Abstract：The change of the CaHZn layer and the corrosion behavior of the zinc coating in saturated Ca(OH)2 solution with decreased pH value from 9.0 to 12.0,which was as simulations of the pore solution with reduced pH value by carbon dioxide,were investigated.And the dissolving mechanism of CaHZn under the experimental condition was also discussed.The prepared galvanized samples with CaHZn coating were immersed in saturated Ca(OH)2 solution with pH value 9.0-12.0 for 30 days,then studied with scanning electron microscope(SEM),energy spectrum analysis(EDS),X-ray diffraction(XRD),Tafel polarization and electrochemical impedance spectroscopy(EIS).The results show that,with decreasing of pH value and increasing of the immersion time,the CaHZn decreases and the ZnO increases simultaneously.The entire surface of the sample is covered by the ZnO when pH value decreases to 9.0.As CaHZn is reduced and ZnO increases,the polarization resistance(Rp),the film resistance(Rc),penetration resistance(Rct)and the diffusion impedance(Ws)decrease,while the self-corrosion current(icorr)increases but still close to the passivation threshold 10-1μA/cm2.
孔纲, 陈九龙, 卢锦堂. 饱和Ca(OH)2溶液pH值对热镀锌钢表面锌酸钙覆盖层的影响[J]. 材料工程, 2010, 0(9): 74-79.
KONG Gang, CHEN Jiu-long, LU Jin-tang. Effects of pH Value of Saturated Ca(OH)2 Solution on CaHZn Coating of Hot Dip Galvanized Steel. Journal of Materials Engineering, 2010, 0(9): 74-79.
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