Zn-Mg合金镀层的表面形貌及在Na_2SO_4中的腐蚀产物分析  

The Surface Appearance of Zn-Mg Alloy Coatings and Analysis of Corrosion Products in Na_2SO_4

作　　者：于萍[1] 王蕾蕾[2] 慕春玲 崔巍[1] 张长桥[1] 邢文国[1] 

机构地区：[1]山东大学化学与化工学院,济南250061 [2]青岛农业大学植保学院,山东青岛266109 [3]山东质量监督检验研究院,济南250014

出　　处：《材料工程》2007年第11期62-65,共4页Journal of Materials Engineering

基　　金：国家重大科技成果推广项目计划(批准号:96010208A)

摘　　要：采用扫描电镜和X射线粉末衍射,对含镁量不同的热镀锌镁合金镀层表面形貌和腐蚀产物进行了分析。分析结果表明,随着镁金属含量的不断增加,镀层金属晶粒明显细化,组织结构趋于均匀。但在含量增至2.5%(质量分数,下同)时,晶界上出现了大量镁的偏析,在镁含量增加至3%时,镁在晶界上的偏析更加严重,镀层腐蚀产物中出现了MgO。从腐蚀理论角度上分析,镁的偏析可形成其对应的阴极保护腐蚀产物,而含有MgO的氧化膜疏松多孔,其致密系数α=0.79。这种膜的化学组成和结构不能有效阻碍腐蚀介质通过,无法阻止腐蚀过程的进一步延伸,从而较好地解释了Zn-3%Mg金属镀层抗大气腐蚀性能下降的原因。The surface appearance and corrosion products of Zn-Mg alloy coatings with different content of Mg were analyzed by SEM and XRD.As a result,crystal particles of coatings were being diminished and structure tends to uniformity with growing Mg content.However,when the content of Mg was 2.5%,there will be Mg segregated in crystal interface.When the content of Mg was 3.0%,there will be more Mg segregated in crystal interface.That was approved by electronic probe.The baseline of diffraction was lifted and diffraction peak was broaden with growing Mg content.That was the content of non-crystal material in corrosion products grew,however,there was MgO in coating corrosion products when the content of Mg was 3.0%.It can be analyzed from the corrosion theory that the cathodic protection corrosion products were formatted by the segregation of Mg,the oxide film containing MgO was loose and cavernous and its compacting factor was 0.79.The reason that the ability to resist corrosion decreased was the chemical composition and structure of the film could not inhibit corrosion medium and corrosion.

关 键 词：热镀Zn-Mg合金镀层 表面形貌 腐蚀产物 镀层组分 

分 类 号：TG174[金属学及工艺—金属表面处理]