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1、PartIBMaterialsScienceandMetallurgyProfGTBursteinCourseB:MaterialsandtheEnvironmentBH1Prof.GTBurstein12lecturesgtb1000@cam.ac.ukCOURSESYNOPSISMostmaterialsinusebymankindareunstablerelativetotheirenvironment.Theusefullifetimeofmaterialsisveryoftenlimitedbycorro
2、sionintheenvironment.Theenvironmentherereferstotheenvironmentinwhichthematerialisused,sometimesanaturalonesuchasairorsea-water,sometimesman-made,suchasfoundinachemicalplant.Corrosionscienceisthereforeasubjectoffundamentalimportancetomaterialsscienceandmaterial
3、sengineering.Corrosioncancausefailureofmaterialsinservice,whichcanbecostly.Itcanalsocausecatastrophicfailure.Andbeyondthat,corrosionisatremendouswasteofmaterialsandoftheenergyrequiredtomakethem:thuscorrosioncontrolisagreensubject.Adetailedunderstandingofcorros
4、ionanditsconsequencesareasvitaltothesuccessfuldesignofahypodermicneedleastheyaretothedesignofsuitablecontainmentforlongtermstorageofnuclearwaste.Asimportantasunderstandingthephenomenaistheabilitytoquantifythem,andtopredictaccuratelythelifetimeofthecomponentins
5、ervice.Wewilllearnsomeoftheimportantmethodsbywhichwecandesignmaterialsagainstcorrosion.Althoughwedeallargelywithmetalcorrosioninthiscourse,webeginbylookingatcorrosionofothermaterialstoo,suchaspolymersandceramics.Mostmaterialsaredegradedmoreathighertemperatures
6、.Thecoursecoversmetaloxidationathightemperatures.Formetals,itisalmostalwaysthepresenceofanoxidefilmofsomesortthatlimitscorrosion,soweintroducetheremarkablephenomenonofpassivityofmetals,bothinairandinaqueousenvironments.Itisremarkable,becausewithoutthisoxidefil
7、m,mostmetalsandalloyswouldbetotallyuseless;yettheoxidefilminsomecasesisasthinas1nm!Thecoursedescribeshowcorrosionoccurs,andwhysomemetalspassivatereadilyinsomeenvironments,butcorrodeinothers.Wewilldescribethephenomenonofmetalcorrosionandpassivationintermsofthee
8、lectrochemistryoftheinterface,strippingittoitssimplestterms,andthenbuildingitupagain.Thethermodynamicsofcorrosionandotherrelatedphenomenawillbeexplored.Butsincethermodynamicscannot