丝束电极的局部腐蚀因子计算VIP专享VIP免费

用丝束电极研究模拟碳化混凝土孔隙液中缓蚀剂对碳钢局部腐蚀的抑制行为董泽华*石维郭兴蓬(华中科技大学化学与化工学院,武汉430074)摘要：应用丝束电极(WBE)的电位/电流扫描技术,研究了含Cl-的模拟碳化混凝土孔隙液中,Q345B碳钢局部腐蚀在空间和时间上的发生和发展特征,同时比较了四乙烯五胺(TEPA)和亚硝酸钠缓蚀剂对局部腐蚀抑制能力的差异.结果表明NO-2离子能快速渗透腐蚀产物层,并抑制锈层下的碳钢活性溶解,而乙烯胺由于在锈蚀层内的扩散速率低,初期反而会促进锈层下的局部腐蚀,随着烯胺分子扩散并吸附于锈蚀层/金属界面处,碳钢活性溶解才受到抑制.电化学阻抗谱(EIS)可反映局部腐蚀的萌发,但难以表征缓蚀剂在碳钢表面的不均匀吸附特征.基于丝束电极表面电位/电流分布所提出的局部腐蚀因子(LF),可定量表征腐蚀的不均匀特征以及缓蚀剂对局部腐蚀的修复能力.关键词：丝束电极;碳化混凝土孔隙液;局部腐蚀;局部腐蚀因子;缓蚀剂中图分类号：O646;TG174.42LocalizedCorrosionInhibitionofCarbonSteelinCarbonatedConcretePoreSolutionsUsingWireBeamElectrodesDONGZe-Hua*SHIWeiGUOXing-Peng(SchoolofChemistryandChemicalEngineering,HuazhongUniversityofScienceandTechnology430074,Wuhan,P.R.China)Abstract：Theinitiation,growth,andtemporalandspatialdistributionoflocalizedcorrosionofQ345Bcarbonsteelincarbonatedconcreteporesolutions(pH9.6)containing0.1mol·L-1Cl-ionswereinves-tigatedusingapotentialandgalvanicmappingtechniquebasedonawirebeamelectrode(WBE).Differentmechanismsforrepairandsuppressiononthestablelocalizedcorrosionbytetraethylenepent-amine(TEPA)andnitritewerecompared.Theresultsindicatethatnitritecaninhibittheactivedissolutionofsteelbeneaththerustlayerbecauseofthefastpenetrationofnitriteintotherustlayer.However,TEPAcanpromoteactivedissolutionundertherustlayerinitiallybecauseofitsslowpenetrationratethroughtherustlayer.ThelocalizedactivedissolutionwasonlyrefrainedafteralongtimebecauseofTEPAmoleculespermeatingintotheinterfacebetweentherustlayerandthesteelmatrix.Electrochemicalimpedancespectroscopy(EIS)wasusefulinallowingustodeterminehowthelocalizedcorrosionwasinitiatedbutfailedtoindicatetheheterogeneousadsorptionoftheinhibitorsonsteel.Anewlocalizedcorrosionfactor(LF)basedongalvanicmappingisproposedandisshowntobeeffectiveforthecharacterizationofthelocalizationofcorrosionandtheinhibitioneffectofinhibitorsonlocalizedcorrosion.KeyWords：Wirebeamelectrode;Carbonatedconcreteporesolution;Localizedcorrosion;Localizedcorrosionfactor;Corrosioninhibitor[Article]www.whxb.pku.edu.cn物理化学学报(WuliHuaxueXuebao)ActaPhys.⁃Chim.Sin.,2011,27(X)：001-009MonthReceived:July1,2010;Revised:October18,2010;PublishedonWeb:November24,2010.∗Correspondingauthor.Email:zehua.dong@gmail.com;Tel:86-027-87543432ThisprojectwasSupportedbytheNationalNaturalScienceFoundationofChina(50971064).国家自然科学基金(50971064)资助项目ⒸEditorialofficeofActaPhysico⁃ChimicaSinica01Vol.27ActaPhys.⁃Chim.Sin.2011丝束电极(WBE)测量是指将相互绝缘的金属丝阵列,有序紧密排列用于模拟整个金属表面的多电极技术.通过循环扫描单根金属丝相对于参比电极的开路电位(OCP)以及与其余金属丝之间的偶接电流来表征金属表面的不平衡腐蚀特征.Tan等人最先提出WBE多电极测量方法[1],WBE除用于测量金属腐蚀[2-3]外,还可测量离子迁移[4],铝合金的选择性溶解[5]等.借助零阻电流计(ZRA)可以精确测量WBE电极表面的短路原电池电流(单电极间的偶接电流),无需担心外部极化可能会破坏微区腐蚀环境,因而特别适合用来研究金属在非扰动状态下自发腐蚀行为,如混凝土内钢筋的非均匀腐蚀,以及生物膜下的微生物腐蚀[6-8].钢筋阻锈剂(缓蚀剂)用于抵御海盐侵蚀、融雪剂等引起的钢筋锈蚀.自1970年...