合金元素Nd对Pb-Ag阳极在H2SO4溶液中电化学行为的影响.pdf

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1、物理化学学~L(WuliHuaxueXuebao)492ActaP．一Chim．Sin．2014，30(3)，492—499March[Article]doi：10．3866／PKU．WHXB201312301WWW．whxb．pku．edu．cn合金元素Nd对Pb-Ag阳极在H2SO4溶液中电化学行为的影响钟晓聪’桂俊峰’于枭影’刘芳洋’蒋良兴，赖延清’李劫’刘业翔’(中南大学冶金与环境学院，长沙410083；中南大学粉末冶金研究院，长沙410083)摘要：采用循环伏安、线性扫描、电化学阻抗和环境扫描电镜对比研究了Pb—Ag和Pb-Ag—Nd阳

2、极的阳极膜和析氧反应．结果表明，合金元素Nd促进了PblPbO／PbSO(1≤n<2)膜层的生长．在高极化电位区间(高于1．2OV(VSHg／HgSO／饱和K2SO溶液))，Nd有利于低价铅的化合物(PbO，PbSO)向a-PbO；FD／3．PbO转变．此外，环境扫描电镜形貌和线性扫描分析证明Pb-Ag—Nd表面生成的阳极膜较Pb．Ag的阳极膜更厚且更致密．因此，Pb．Ag．Nd阳极表面的阳极膜可以给合金基底提供更好的保护．另一方面，电化学阻抗测试揭示了两种阳极的析氧反应均受中间产物的形成和吸附控制．Nd可以降低阳极膜，电解液界面处中间产物的吸附

3、阻抗且增加中间产物的覆盖率，从而提高析氧反应活性．综上所述，合金元素Nd可提高Pb—Ag阳极的耐腐蚀性，降低阳极电位进而起到节能降耗的作用．关键词：电沉积；阳极膜：钝化：析氧：耐腐蚀性中图分类号：0646InfluenceofAlloyingElementNdontheElectrochemicalBehaviorofPb-AgAnodeinH2SO,SolutionZHONGXiao—Cong’GUIJun-Feng’YUXiao-Ying’LIUFang-Yang’JIANGLiang-Xing’·’LAIYan—Qing’LIJie’LIU

4、Ye-Xiang’(SchoolofMetallurgyandEnvironment,CentralSouth【fChangsha410083，R．China；2PowderMetallurgyResearchInstitute,CentralSouthUniversity,Changsha410083，PR．China)Abstract：Anodiclayersandoxygenevolutionreaction(OER)ofPb-AgandPb—Ag—Ndanodeswereinvestigatedbycyclicvoltammetry，li

5、nearsweepvoltammetry(LSV)，electrochemicalimpedancespectroscopy(EIS)，andenvironmentalscanningelectronmicroscopy(ESEM)．AloyingwithNdpromotedtheformationofPb／PbO~／PbSO4(1≤n<2)．NdfacilitatedthetransformationofPbOandPbSO4toG-PbO2and／3-Pb02，atpotentialabove1_2VVSHg／Hg2SO,(saturated

6、K2SO4solution)．ESEMandLSVindicatedthattheanodiclayerformedonthePb．．Ag--NdanodewasthickerandmorecompactthanthatformedonthePb-Aganode．Consequently。theanodiclayeronthePb—Ag-Ndanodecouldprovidebetterprotectionformetallicsubstrates．EISindicatedthattheOERwasdeterminedbytheformation

7、andadsorptionofintermediates．NdenhancedtheOERreactivity．becauseofasmalleradsorptionresistanceandlargercoverageofintermediatesattheanodiclayer／electrolyteinterface．Insummary．alloyingwithNdcanenhancethecorrosionresistanceandreducetheenergyconsumptionofPb-Aganodeduetoloweranodic

8、potentia1．KeyWords：Electrowinning；Anodiclayer；Passivation；Oxygenevol