国际电化学会议报告PPT Electrochemical Sensors for Industrial Lubricant Analysis

Y.Yang,S.TereshkoandS.DanylukTheGeorgeW.WoodruffSchoolofMechanicalEngineeringGeorgiaInstituteofTechnologyElectrochemicalSensorsforIndustrialLubricantAnalysisInternationalSymposiumonFrontiersofElectrochemicalScienceandTechnology,August12-15,2021,Xi'an,ChinaAgendaIntroductionOilanalysisbasicsElectrochemicalviewvs.tribologicalviewElectrochemicalSensorsParallelPlateElectrode(PPE)DIvs.saltwaterwithEISVirginoilvs.usedoilwithEISSummaryWhyOilLubricants?Industriallubricants,beingalifebloodofanengine,isvitaltoengine.ThefunctionsoflubricantsincludeSeparationofmovingpartsandfrictionreduction,Wearprevention,Contaminantsuspension,Neutralizationofcorrosiveacidsfromthecombustionprocess,DissipationofheatProvidingotherperformanceimprovingfeatures.Lubricantsconsistofamineralorsyntheticbaseoilandotherspecificallydesignedadditives.Oildeteriorationratedependsontheoperatingconditions,thefuelquality,theambientconditions,andoperatingparameters.SchemesofOil-MetalInterfaceTribologicalviewPhysisorptionChemisorptionChemicalreaction(wearandre-oxidation)ElectrochemicalviewElectricaldoublelayerCharge-transferresistanceChemicalreaction(electricalconduction)MetalOilMetal-+-+-+-++-----------------+++++----------------+-+-+-+-+++++++++++++BaseStocksandOilAdditivesBaseStocksMineralParaffinsNaphthenesAromaticsAsphaltenesSyntheticPolyalphaolefins(45%)Organicester(25%)Polyglycols(10%)WidecarbonnumberdistributionC18-C40.AdditivesSurfactants–formingprotectivefilm,neutralizingtheacidicproductsofcombustionandthermo-oxidation;interactingwithwater,glycolandotherpolarcontaminantsDispersants–suspendingsootsOxidationinhibitors–reducingtheoxidationrateofalubricantAnti-wearagents–providingprotectionagainstwearbyformingprotectivefilmsonmetalsurfacesElectrochemicalOilSensorsOilCharacteristicsComplexcombinationofhydrocarbonsNon-aqueouscolloidalpolymersLow,primarilyionicelectricalconductivityMolecularweight500to50,000Polarfunctionheadandnon-polartailsDiffusioncoefficient10-8to10-12cm2/sSymmetricElectrolyteФE-vDAQComputervOPAFabricationofSensorElectrodesGlasssubstrateGlasssubstrateMetalfilmGlasssubstrateMetalfilmPRMetaldepositionPhotolithographyGlasssubstrateMetaletchGlasssubstrateGlasssubstrateAssemblySensorCharacteristicsExperimentalsetupincludingsensorelectrodesSensitivitycurveCalibrationcurveSensorOutputinWaterEISforPPEinDIandSaltWaterGlassSubstrateGlassSubstrate1mmSpaceAuAlIdealpolarizedinterfacewithdoublelayerforDIWarburgimpedanceDoublelayerinserieswithWarburgresistanceEISforPPEinVirginandUsedOilGlassSubstrateGlassSubstrate1mmSpaceAuAlHigherImpedancefortheusedoils.EffectofElectrodeSurfacesConfigurationofElectrodesVirginoilUsedoilProposedModelforOilConductionCBULKRBulkCCPERCTEquivalentcircuitincludingWarburgimpedanceandchargetransferresistanceZWBulkInterfaceSummaryOilconductionbehavesastwo-time-constantsprocessIonicconductionathighfrequencyIonicdiffusionat