資源描述:
《Corrosion Behavior of Mild Steel in Hydrochloric Acid Solutions.pdf》由會員上傳分享,免費在線閱讀,更多相關內容在學術論文-天天文庫。
1、Int.J.Electrochem.Sci.,3(2008)806-818www.electrochemsci.orgCorrosionBehaviorofMildSteelinHydrochloricAcidSolutions*EhteramA.Noor,AishaH.Al-MoubarakiKingAbdEl-AzizUniversity,Girls’CollegeofEducation,DepartmentofChemistry,Jeddah-9470,KSA*E-mail:m7o7o7n@hotmail.c
2、omReceived:9April2008/Accepted:6May2008/Published:29May2008Thecorrosionbehaviourandmechanismformildsteelinhydrochloricacidsolutionswasstudiedbychemical(hydrogenevolution,HE&massloss,ML)andelectrochemical(electrochemicalimpedanceospectroscopy&potentiodynamicpolarization)methodsat25C.Thechemicalresul
3、tsrevealedthatmildsteelcorrodesinHClsolutionswitharectionconstantof0.56andthecorrosionrateincreaseswiththeincreaseinacidconcentration.MicrostructuralstudiesformildsteelafterimmersioninHClsolutionsofdifferentconcentrationsshowedgeneralandpittingcorrosionandthelatterbecomesmorepronouncedathigherlevel
4、ofHClconcentration.Accordingly,itwasfoundthatRctvaluedecreaseswhilebothCdlandicorr.valuesincreasewithincreasingHClconcentration.PDPresultsrevealedthatthesteeldissolutionisanodicallycontrolled.EstimationoftheratioZ/vsfromPDPdataindicatedthatmildsteeldissolutionoccursviamultistepmechanism.Thismechani
5、sminvolvestwostepseachofthemischaracterizedbyoneelectronreleaseandoneofthemistheratedeterminingstep.Therate-determiningstepmayinvolveadsorbed[FeOH]adsand/or[FeClOH]adsgroups.Keywords:Mildsteel;Corrosion;Hydrochloricacid;Impedance;Polarization1.INTRODUCTIONMildsteelisoneofthemajorconstructionmateria
6、ls,whichisextensivelyusedinchemicalandalliedindustriesforthehandlingofacid,alkaliandsaltsolutions[1].Hydrochloricacidisthemostdifficultofthecommonacidstohandlefromthestandpointsofcorrosionandmaterialsofconstructions.Extremecareisrequiredintheselectionofmaterialstohandletheacidbyitself,eveninrelativ
7、elydiluteconcentrationsorinprocesssolutionscontainingappreciableamountofhydrochloricacid.Thisacidisverycorrosivetomostofthecommonmetalsandalloys[2].Theaimofthisworkistoinvestigatethecorrosionbehaviourandmec