Zn和ZnAl合金涂层在西沙严酷海洋大气环境下的腐蚀行为的比较  

Comparison of Corrosion Behavior of Pure Zn and Zn-Al Alloy Coating in Serious Xisha Marine Atmosphere Environment

作　　者：刘安强[1] 肖葵[2] 李晓刚[2] 袁建鹏[1] 

机构地区：[1]北京矿冶研究总院,北京1001603 [2]北京科技大学腐蚀与防护中心,北京100083

出　　处：《热喷涂技术》2015年第4期46-52,共7页Thermal Spray Technology

摘　　要：通过现场暴晒实验,研究纯Zn涂层和ZnAl合金涂层在西沙海洋大气环境下的腐蚀行为。利用扫描电镜对腐蚀产物后的表面形貌进行观察,并分别用EDS及XRD对腐蚀产物的元素分布及相组成进行分析。结果表明,腐蚀初期两种涂层的腐蚀产物主要为羟基氯化锌(Zn_5(OH)_8Cl_2H_2O);腐蚀后期,纯Zn涂层表面逐渐生成了疏松多孔的腐蚀产物层,腐蚀产物主要由Zn_5(OH)_8Cl_2H_2O、ZnCO_3、Zn_5(CO_3)_2(OH)_6Zn和ZnO组成;ZnAl合金涂层的腐蚀产物主要为Zn_5(OH)_8Cl_2H_2O、ZnCO_3、Zn_5(CO_3)_2(OH)_6Zn、ZnO和Al_2O_3。随盐雾时间增长,ZnAl合金涂层表面形成了致密的腐蚀产物层,腐蚀产物层的屏蔽作用有效阻碍腐蚀介质的渗入,使其腐蚀速率快速降低。Corrosion behavior of pure Zn coating and Zn-Al alloy coating after atmospheric exposure in Xisha islands was investigated.The surface morphologies,the elements distribution and phase compositions of corrosion products were observed by SEM,EDS and XRD,respectively.The results indicate that the main corrosion product of two kinds of coatings was zinc hydroxide chloride(Zn_5(OH)_8Cl_2H_2O) at initial corrosion stage.During the later stage,corrosion products layer on pure zinc coating samples are loose and porous,the corrosion product was mainly composed of Zn_5(OH)_8Cl_2H_2O,Zn_5(CO_3)_2(OH)_6,ZnCO_3,and ZnO.The corrosion products of Zn-Al alloy coating were Zn_5(OH)_8Cl_2H_2O,Zn_5(CO_3)_2(OH)_6,ZnCO_3,ZnO and Al_2O_3.When the test time continued,the surface of Zn-Al alloy coating was covered with a dense corrosion product layer which effectively isolated corrosion medium from the substrate.The corrosion rate of Zn-Al alloy coating declined rapidly with prolonging test time.

关 键 词：纯Zn涂层 ZnAl合金涂层 海洋大气 腐蚀 西沙 

分 类 号：TG174.442[金属学及工艺—金属表面处理]