涂膜破坏后膜下镀锌钢板大气腐蚀扩展研究

    通过SEM和EDS研究了带有划痕的涂装镀锌钢板在海洋大气环境下暴露一年半后,划痕周围涂膜下腐蚀产物的扩展行为,并分别对电镀锌、热镀锌、电镀锌预磷化的材料进行了耐蚀性比较.结果表明，在划痕周围涂膜下镀层的耐蚀性与镀层制作工艺无关,而与镀层厚度有关；涂膜前的预磷化对耐蚀性产生了不利影响；虽然涂膜与镀锌层间发生分离,但对镀层的耐蚀性没有产生影响；海洋大气环境存在的氯容易富集在腐蚀产物的前端,而硫则较均匀的分布在整个腐蚀产物转化区.

ATMOSPHERIC CORROSION PROPAGATION ON GALVANIZED STEELS UNDERNEATH PAINTS WITH SCRATCHS

    Corrosion propagation on galvanized steels underneath paints with a desired scratchs was studied after atmospheric exposure for one and half year by SEM and EDS,meanwhile the corrosion resistance of the painted steels which were electrogalvanized,hot-dip galvanized and electrogalvanized and then phosphated before painting was compared.The results showed that the corrosion resistance of the steels underneath paints with the desired scratchs was independent on the fabrication means of Zn coatings but not the thickness Zn coatings.Phosphate treatment showed a harmful effect on the corrosion resistance in this study.The hot-dip galvanized steel showed the same corrosion resistance as the electrogalvanized steel even though detachment occurred between the Zn coating and the paint.Chlorine enriched in front of the corrosion product while sulfur distributed the whole area.