摘要
为了提高镁合金的耐蚀性,采用钼酸盐-高铁酸盐体系在AZ31镁合金表面制备转化膜并研究其腐蚀行为。通过对照分析不同变量成膜的腐蚀电位和腐蚀电流密度,确定了最优成膜工艺:0.300 mol/L Na2MoO4+0.120 mol/L NaF+0.050 mol/L Na3PO4+0.075 mol/L K2FeO4,p H值为5,温度55℃,时间30 min。在最优方案处理的镁合金表面获得大小不等、分布均匀的球状颗粒转化膜层。由XRD分析可知,膜层主要成分为MoO3,MoO2,MoO(OH)2。通过电化学检测分析表明,钼酸盐-高铁酸盐转化膜层的自腐蚀电流密度较基材降低了约3个数量级,自腐蚀电位提高了0.46 V。通过SEM腐蚀形貌分析发现,腐蚀面上存在由酸蚀析氢造成的细小龟裂纹,对基体材料起到保护作用。
In order to modify the corrosion resistance of Mg alloy,a molybdenum-ferrate conversion film was prepared on the surface of AZ31magnesium alloy in molybdenum-ferrate system.By comparing and analyzing the corrosion potential and corrosion current density of the films prepared with different parameters,the optimal film forming process was confirmed as follows:0.300 mol/L Na2MoO4+0.120 mol/L NaF+0.050 mol/L Na3PO4+0.075 mol/L K2FeO 4,pH=5,30 min of treatment time and 55℃of the temperature.After treated by the optimal conditions,the Mg alloy surface formed a conversion film,on which many spherical particles with various sizes evenly distributed.From the XRD analysis,the main components of the film were MoO3,MoO2and MoO(OH)2.The electrochemical detection analysis suggested that the self-corrosion current density of molybdate-ferrate conversion film was decreased by about 3 orders of magnitude compared with the original sample,and the self-corrosion potential was increased by 0.46 V.By SEM analysis of the corrosion morphology,it was found that small turtle cracks caused by acid etching hydrogen were observed on the corrosion surface,which had a protective effect on the substrate.
作者
伍良银
姜雪婷
张菊
李雪锋
刘静
杨峰
WU Liang-yin;JIANG Xue-ting;ZHANG Ju;LI Xue-feng;LIU Jing;YANG Feng(School of Materials and Architectural Engineering,Guizhou Normal University,Guiyang 550001,China)
出处
《材料保护》
CAS
CSCD
北大核心
2020年第9期70-75,81,共7页
Materials Protection
基金
贵州省科学技术基金[黔科合基础(2017)1118
黔科合平台人才(2016)5607]
贵州师范大学大科项目(DK2018A052)资助。
关键词
AZ31镁合金
钼酸盐-高铁酸盐
转化膜
电化学
耐蚀性
AZ31 magnesium alloy
molybdate-ferrate
conversion film
electrochemistry
corrosion resistance
