Coatings-and-Inhibitor-Ch-15VIP专享VIP免费

CoatingandInhibitors•IntroductiontoCorrosionMonitoring•WhatisCorrosionMonitoring?•Thefieldofcorrosionmeasurement,control,andpreventioncoversaverybroadspectrumoftechnicalactivities.Withinthesphereofcorrosioncontrolandprevention,therearetechnicaloptionssuchascathodicandanodicprotection,materialsselection,chemicaldosingandtheapplicationofinternalandexternalcoatings.Corrosionmeasurementemploysavarietyoftechniquestodeterminehowcorrosivetheenvironmentisandatwhatratemetallossisbeingexperienced.Corrosionmeasurementisthequantitativemethodbywhichtheeffectivenessofcorrosioncontrolandpreventiontechniquescanbeevaluatedandprovidesthefeedbacktoenablecorrosioncontrolandpreventionmethodstobeoptimized.Awidevarietyofcorrosionmeasurementtechniquesexists,including:NonDestructiveTestingAnalyticalChemistryAnalyticalChemistry•Ultrasonictesting•pHmeasurement•Radiography•Dissolvedgas(O2,CO2,H2S)•Thermography•Metalioncount(Fe2+,Fe3+)•Eddycurrent/magneticflux•Microbiologicalanalysis•IntelligentpigsOperationalDataFluidElectrochemistry•pH•Potentialmeasurement•Flowrate(velocity)•Potentiostaticmeasurements•Pressure•Potentiodynamicmeasurements•Temperature•A.C.impedanceCorrosionMonitoring•Weightlosscoupons•Electricalresistance•Linearpolarization•Hydrogenpenetration•GalvaniccurrentClassificationofcorrosionprotectionmethodsActivecorrosionprotectionPassivecorrosionprotectionPermanentcorrosionprotectionTemporarycorrosionprotectionProtectiveMetallicCoatings•Metalliccoatingsprovidealayerthatchangesthesurfacepropertiesoftheworkpiecetothoseofthemetalbeingapplied.Theworkpiecebecomesacompositematerialexhibitingpropertiesgenerallynotachievablebyeithermaterialifusedalone.Thecoatingsprovideadurable,corrosionresistantlayer,andthecorematerialprovidestheloadbearingcapability.Thedepositionofmetalcoatings,suchaschromium,nickel,copper,andcadmium,isusuallyachievedbywetchemicalprocessesthathaveinherentpollutioncontrolproblems.(corrosioncostsstudy)•Alternativemetaldepositionmethodshavereplacedsomeofthewetprocessesandmayplayagreaterroleinmetalcoatinginthefuture.Metalliccoatingsaredepositedbyelectroplating,electrolessplating,spraying,hotdipping,chemicalvapordepositionandionvapordeposition.Someimportantcoatingsarecadmium,chromium,nickel,aluminumandzinc.•Platingandsurfacetreatmentprocessesaretypicallybatchoperations,inwhichmetalobjectsaredippedintoandthenremovedfrombathscontainingvariousreagentstoachievethedesiredsurfacecondition.Theprocessesinvolvemovingtheobjectbeingcoatedthroughaseriesofbathsdesignedtoproducethedesiredendproduct.Theseprocessescanbemanualorhighlyautomatedoperations,dependingonthelevelofsophisticationandmodernizationofthefacilityandtheapplication.•OrganicProtectiveCoating•Manypaints,coatingsandhighperformanceorganiccoatingshavebeendevelopedasaneedtoprotectequipmentfromenvironmentaldamage.Ofprimeimportanceinthedevelopmentofprotectivecoatingswasthepetroleumindustrythatproducedmostofthebasicingredientsfromwhichmostsyntheticresinsweredeveloped.•MetalCladding•Thecorrosionresistanceofasubstratecanbeimprovedbymetallurgicallybondingtothesusceptiblecorealloyasurfacelayerofametaloranalloywithgoodcorrosionresistance.Thecladdingisselectednotonlytohavegoodcorrosionresistancebutalsotobeanodictothecorealloybyabout80to100mV.Thusifthecladdingbecomesdamagedbyscratches,orifthecorealloyisexposedatdr...