Generation Reason and Corrosion Characteristics of Cavity of Alloy Layer of Tinplate

摘要

Surface morphology of alloy layer of tinplate was studied by scanning electron microscope (SEM) .It was found that the cavity of alloy layer was a critical factor causing rapid decline of the corrosion resistance of tinplate. Rely on the layer on layer debonding technology of glow discharge spectrum (GDS) ,the content of C and 0 on the boundary of alloy layer and black plate was analyzed.lt proved for the first time, making use of experimental simulation, that the formation of cavity of alloy layer was due to incorrect pretreatment of black plate before electrotinning. By electrochemical atomic force microscope ( E-CAFM) , the corrosion characteristic of cavities of alloy layer of tinplate was studied on line and in situ, which proved that the cavity of alloy layer was the internal factor causing perforating corrosion of tinplate when applied to food packaging material. Through measuring the corrosion depth of cavity of alloy layer in situ after different corrosion time, it was found that the dynamic equation of pitting corrosion generated in the cavity of alloy layer conformed to logarithm law.