无锌花镀锌板表面灰色斑点的形成原因分析  

Analysis on the Formation Mechanism of Gray Spots on the Surface of Spangle-Free Galvanized Sheet

作　　者：袁清[1] 徐光[1] 戴方钦[1] 郭丽涛 李运成 YUAN Qing;XU Guang;DAI Fang-qin;GUO Li-tao;LI Yun-cheng(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081 ,China;Shandong Guanzhou Company Limited by Shares,Liaocheng 252500,China;Huangshi Sunny Xinye Strip Company Ltd.,Huangshi 435100,China)

机构地区：[1]武汉科技大学耐火材料与冶金国家重点实验室,湖北武汉430081 [2]山东冠洲股份有限公司,山东聊城252500 [3]黄石山力兴冶薄板有限公司,湖北黄石435100

出　　处：《材料保护》2019年第5期137-142,156,共7页Materials Protection

基　　金：国家自然科学基金项目(51874216);国家自然科学基金青年基金项目(51274154);湖北省技术创新重大项目(2017AAA116);河北钢铁联合研究基金(E2018318013)资助

摘　　要：无锌花镀锌板光整后下线时未发现灰色斑点,但放置20余天后表面出现深浅不一的灰色斑点。针对这种表面缺陷,对灰色斑点处镀锌板进行了微观形貌观察与能谱分析。结果表明:镀锌层晶界处含有大量的Fe、O元素,Zn元素较少;正常镀层处Zn元素较多,Fe元素较少。深浅斑点的出现与镀锌板所处的环境因素以及钝化效果和工艺有关。在一定的环境如高温或潮湿条件下,镀锌板锌粒间成为腐蚀的起点,导致锌层完整性的破坏。其次,钝化效果不好可能导致镀锌板出现钝化层不均匀的现象,造成钝化较薄的区域容易发生表面腐蚀。Gray spots appeared on the surface of spangle-free galvanized sheet after storing for about twenty days, while no gray spots were found after temper rolling. Regarding to this surface defect, the morphology observation and energy spectrum analysis on the gray spots were conducted in the present study. Results indicated that a large amount of Fe and 0 existed in the grain boundary of zinc layer while there was a small amount of Zn. While in the normal zinc layer, Zn was more and Fe was less. The appearance of gray spots was related to the surrounding environment and passivating process in the galvanized sheets. The integrity of zinc coating was destroyed because the grain boundaries between zinc granules served as the corrosion sprouts at certain environment. In addition, the baddish passivation effect caused the uneven galvanizing coating, making the corrosion at the weaker passivation area.

关 键 词：无锌花镀锌板 斑点 能谱分析 面扫描 钝化 

分 类 号：TG172.1[金属学及工艺—金属表面处理]