AdvancedMaterialsResearchVol.460(2012)pp7-10Onlineavailablesince2012/Feb/10atwww.scientific.net©(2012)TransTechPublications,Switzerlanddoi:10.4028/www.scientific.net/AMR.460.7ElectrochemicalStudyoftheAdditive-effectonSnElectrodepositioninaMethansulfonateAcidElectrolyteJinMingLong1,a,ZhuZhang2,b,ZhongChengGuo2,c,XiaoYunZhu1,dandHuiHuang2,e1SchoolofMaterialsScienceandEngineering,KunmingUniversityofScienceandTechnology,Kunming650093,China2FacultyofMetallurgyandEnergyEngineering,KunmingUniversityofScienceandTechnology,Kunming650093,Chinaajinminglong@sina.com,bzzpenguin@163.com,cguozhch@vip.163.com,dzuxiaoyun1998@126.com,ehuihuanghan@163.comKeywords:Tinplating;Stannousmethanesulfonate;Additive;Overpotential;EIS.Abstract.TheeffectofthreeorganicadditivesinstannousmethanesulfonatebathsoncathodicoverpotentialandFaradaicimpedanceoftin-electrodepositionwerestudiedbymeasuringcathodicpolarizationcurves,galvanostaticresponsesandelectrochemicalimpedancespectroscopy.Theresultsshowthatthecompositeadditiveconsistingofthreeorganiccompoundscansignificantlyincreasethecathodicpolarization,crystallizationoverpotentialandchargetransferresistance,whichisverybeneficialtoimprovecoatingqualityandresultinafine-grainedandsmoothmatttincoating.IntroductionThetinplatingbathstraditionallyusedincludesulfate,fluoborate,sulfophenylate,andsoon[1-3].Forthereasonoftoxicanddifficulttotreatwastewater,theycouldhardlymeettheneedofenvironmentalprotection.Nowadaysasanewkindofenvironmentalfriendlyelectroplateliquid,methanesulfonicacidelectrolytehasbeenusedmoreandmorepopularandhasbeengraduallyreplacingthetraditionalbaths.Theadditivesinstannousmethanesulfonatebathsplayanimportantroleinelectrodepositionofthetincoatingswhichwouldbeloosened,dendriticandpooradherentwithmatrixintheabsenceoforganicadditives.Soorganicadditivesareoftenusedtoobtaincompactelectrodepositsoftin.Allkindsofadditivescanbeidentifiedsuchassurfactants,brighteners,andgrainrefiners[4,5].Martyaketal.[4]foundthatthepr