Influence of the lithium content on the negative difference effect of Mg-Li alloys  

作　　者：C.Q.Li D.K.Xu Z.R.Zhang E.H.Han 

机构地区：[1]School of Materials and Energy,Guangdong University of Technology,Guangzhou 510006,China [2]Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China

出　　处：《Journal of Materials Science & Technology》2020年第22期138-145,共8页材料科学技术（英文版）

基　　金：supported financially by the National Key Research and Development Program of China (Nos. 2017YFB0702001 and 2016YFB0301105);the National Natural Science Foundation of China Projects (Nos. 51901047,51871211 and51701129);the Doctor Startup Fund of Natural Science Foundation Program of Liaoning Province (No. 2019-BS-200);the Strategic New Industry Development Special Foundation of Shenzhen (No. JCYJ20170306141749970);the Funds of International Joint Laboratory for Light Alloys, the Liaoning Bai Qian Wan Talents Program;the Domain Foundation of Equipment Advance Research of 13th Five-year Plan (No. 61409220118);the Innovation Fund of Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS);the National Basic Research Program of China (No. 2013CB632205)。

摘　　要：The so-called 'negative difference effect'(NDE) was often defined by the increasing rate of hydrogen evolution from magnesium(Mg) surface under anodic polarization.In this work,a series of electrochemical tests and microstructure observations were performed to provide an evidence that the NDE of Mg-Li alloys can be retarded by increasing lithium content.Potentiostatic,galvanostatic and potentiodynamic polarization experiments using Mg-xLi(x=4,7.5 and 14 wt%) alloys electrodes indicated that Mg-4 Li alloy maintained the enhancing NDE prior to anodic dissolution as that of conventional Mg alloys.However,the emergence of β-Li phase weakened the NDE of duplex Mg-7.5 Li alloy at a low anodic current density,but it was still enhanced apparently after a high applied anodic value(more than 2 mA/cm^2).The surface observations,including the plane and cross-sectional morphologies,confirmed that the cracked surface film derived from the anodic dissolution resulted in the catalytic activity of NDE for Mg-4 Li and Mg-7.5 Li alloys.Furthermore,the NDE of Mg-14 Li alloy was suppressed obviously after a prior applied anodic polarization,which was attributed to the persistent and integrated surface film which endured a higher level of applied anodic potential and current.

关 键 词：Mg-Li alloy Negative difference effect Electrochemical property CORROSION Anodic dissolution 

分 类 号：TG146.22[一般工业技术—材料科学与工程]