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A member of NSG Group1A member of NSG Group1Application of Inorganic Chemistry in IndustryFlat Glass and Coatings On GlassDrTroyManningAdvancedTechnologist,On-lineCoatingsPilkingtonEuropeanTechnicalCentreHallLaneLathomUKtroy.manningpilkington2Application of Inorganic ChemiOutlineOverviewofFlatGlassindustryandNSG/PilkingtonFlatGlassmanufactureFloatGlassProcessCoatingtechnologywithintheglassindustryChemicalVapourDepositionExamplesofonlinecoatingapplicationsLowEmissivity/SolarControlSelfCleaningSummarySuggestedReading3OutlineOverview of Flat Glass GlobalFlatGlassMarketGlobalMarket37milliontonnes(4.4billionsq.m)BuildingProducts33mtonnes-Automotive4mtonnesOfwhich24million=highqualityfloatglass3million=sheet2million=rolled8million=lowerqualityfloat(mostlyChina)GlobalValueAtprimarymanufacturelevel15billionAtprocessedlevel50billion4Global Flat Glass MarketGlobalNSGandPilkingtoncombinedAglobalglassleaderthepureplayinFlatGlassCombinedannualsalesc.4billionEqualtoAsahiGlassinscale,mostprofitableinFlatGlassOwnership/interestsin46floatlines6.4milliontonnesannualoutputWidenedAutomotivecustomerbase36,000employeesworldwideManufacturingoperationsin26countriesSalesin130+countries5NSG and Pilkington combinedA gManufactureofFlatGlassFourmainmethodsPlateGlass(1688)moltenglasspouredontoaflatbed,spread,cooledandpolishedSheetGlass(1905)continuoussheetofglassdrawnfromtankofmoltenglassRolledGlass(1920)moltenglasspouredontototworollerstoachieveaneventhickness,makingpolishingeasier.Usedtomakepatternedandwiredglass.FloatGlass(1959)moltenglasspouredontobedofmoltentinanddrawnoffincontinuousribbon.Giveshighqualityflatglasswitheventhicknessandfirepolishfinish.320float-glasslinesworldwide6Manufacture of Flat GlassFour Melting furnaceFloat bathCooling lehrContinuos ribbon of glassCross cuttersLarge plate lift-off devicesSmall plate lift-off devicesRaw material feedTheFloat-GlassProcessOperates non-stop for 10-15 years6000 km/year0.4 mm-25 mm thick,up to 3 m wide7Melting furnaceFloat bathCooliTheFloatGlassProcess8The Float Glass Process8Rawmaterials9Raw materials9MeltingFurnace10Melting Furnace10FloatBath11Float Bath11FloatGlassPlant12Float Glass Plant12TheFloat-GlassProcessFine-grainedingredients,closelycontrolledforquality,aremixedtomakebatch,whichflowsasablanketontomoltenglassat1500Cinthemelter.Thefurnacecontains2000tonnesofmoltenglass.Afterabout50hours,glassfromthemelterflowsgentlyoverarefractoryspoutontothemirror-likesurfaceofmoltentin,startingat1100Candleavingthefloatbathasasolidribbonat600C.Despitethetranquillitywithwhichfloatglassisformed,considerablestressesaredevelopedintheribbonasitcools.13The Float-Glass ProcessFine-grRawMaterialsOxide%in glass Raw material sourceSiO272.2SandNa2O13.4Soda Ash(Na2CO3)CaO8.4Limestone(CaCO3)MgO4.0Dolomite(MgCO3.CaCO3)Al2O31.0Impurity in sand,Feldspar or CalumiteFe2O30.11Impurity in sand or Rouge(Fe2O3)SO30.20Sodium sulphateC0.00Anthracite14Raw MaterialsOxide%in glRawmaterialsSiO2Very durable,BUT high melting point(1700C)!+Na2OMelts at a lower temperature,BUT dissolves in water!+CaOMore durable,BUT will not form in bath without crystallisation+MgOGlass stays as a super-cooled liquid in bath,no crystallisation+Al2O3Adds durability+Fe2O3Adds required level of green colour for customer15Raw materials SiO2Very durablChemistryofGlassImportant glassmaking chemistry:basic reactionsNa2CO3 +SiO2 1500C Na2SiO3 +CO2Na2SiO3 +x SiO2 Na2SO4 (Na2O)(SiO2)(x+1)Digestion16Chemistry of GlassImportant glCompositionofGlass17Composition of Glass17StructureofGlassRandom network of SiO4-tetrahedral units.Na-O enter Si-O network according to valency Network FormersCa and Mg Network Modifiers make structure more complex to prevent crystallisation 18Structure of GlassRandom netwoBody-tintedGlassIonResulting Colour of GlassFerrous(Fe2+)BlueFerric(Fe3+)YellowFe2+Fe3+GreenSelenium(SeO2)BronzeCobalt(Co2+)Grey/BlueNickel(Ni2+)Grey19Body-tinted GlassIonResulting CIELa*b*colourspace20CIE L a*b*colour space20CIELa*b*colourspace21CIE L a*b*colour space21FunctionsofaWindowLightinhomes,officesLightoutshops,museumdisplaysHeatinheatingdominatedclimatesHeatoutcoolingdominatedclimatesCanchangepropertiesofglassbyapplyingcoatingstothesurface22Functions of a WindowLight in Makingawindowfunctional-coatingsAwidevarietyofcoatingtechnologiesareutilisedbytheglassindustrySprayPyrolysisPowderSprayChemical Vapour DepositionSputterCoatingThermalEvaporationCoatingsSolGelCoatingsTheseareappliedOnLinei.e.astheglassisproducedonthefloatlineOffLinei.e.coatingnotnecessarilyproducedatthesamelocation23Making a window functional-cVariationsofCVDAtmosphericPressureAPCVDLowPressure-LPCVDAerosolAssisted-AACVDMetalorganicMOCVDCombustion/FlameCCVDHotWire/FilamentHWCVD/HFCVDPlasmaEnhanced-PECVDLaserAssistedLACVDMicrowaveAssistedMWCVDAtomicLayerDepositionALD24Variations of CVDAtmospheric PChemicalVapourDeposition25Chemical Vapour Deposition25ChemicalVapourDepositionMaingasflowregionGasPhaseReactionsSurfaceDiffusionDesorptionofFilmPrecursorByProductsDiffusiontosurface26Chemical Vapour DepositionMainChemicalVapourDepositionAnimation kindly supplied by Dr.Warren Cross,University of Nottingham27Chemical Vapour DepositionAnimCVDprocessesandparametersProcessParametersTransportPrecursorsGasphasereactionPressure,temperature,flowconditions,boundarylayerthickness,gasphaseconcentration,precursors,carriergasDiffusionPressure,temperature,flowconditions,boundarylayerthickness,gasphaseconcentrationAdsorptionTemperature,gasphaseconcentration,numberandnatureofsitesSurfacereactionTemperature,natureofsurfaceDesorptionofby-productsTemperature,pressure,natureofsurfaceDiffusiontolatticesiteTemperature,surfacemobility,numberofvacantsites28CVD processes and parametersPrCVDPrecursorPropertiesVolatilegas,liquid,lowmeltingpointsolid,sublimablesolidPureStableundertransportReact/DecomposecleanlytogivedesiredcoatingminimisecontaminantsCanbesinglesourceordual/multi-source29CVD Precursor PropertiesVolatiCVDPrecursorsSingleSourcepyrolysis(thermaldecomposition)e.gTi(OC2H5)4TiO2+4C2H4+2H2O(400C)Oxidatione.gSiH4(g)+O2(g)SiO2(s)+2H2(g)Reductione.g.WF6(g)+3H2(g)W(s)+6HF(g)Dualsourcee.g.TiCl4(g)+4EtOH(g)TiO2(s)+4HCl(g)+2EtOEt(g)30CVD PrecursorsSingle Source DualSourceandSingleSourcePrecursorsFilmDual SourceSingle SourceGaAsGaCl3+AsH3Me2Ga(AsH2)TiNTiCl4+NH3Ti(NMe2)4WSiWCl6+SiH4W(SiR)4TiO2TiCl4+H2OTi(OiPr)4CdSeCdMe2+H2SeCd(SeR)231Dual Source and Single Source TransportofPrecursorsBubblerforliquidsandlowmeltingsolidsDirectLiquidInjectionsyringeandsyringedriverforliquidsandsolutionsSublimationforsolidshotgaspassedoverheatedprecursorAerosolofprecursorsolutions32Transport of PrecursorsBubblerEffectofTemperatureonGrowthRateIndependent of temperature33Effect of Temperature on GrowtFlowconditionsLaminar Flow regimeTurbulent Flow Regime34Flow conditionsLaminar Flow reReynoldsNumberDimensionlessnumberdescribingflowconditionsr=r=Mass density related to concn and partial pressureu=average velocitym=viscosityL=relevant length,related to reactor dimensionsIf Re 1000 fully turbulent flowReality is between the two extremes35Reynolds NumberDimensionless nDimensionlessNumbersReducesthenumberofparametersthatdescribeasystemMakesiteasiertodeterminerelationshipsexperimentallyForexample:DragForceonaSphereVariables:Force=f(velocity,diameter,viscosity,density)Canbereducedto2“dimensionlessgroups”:Dragcoefficient(CD)andReynoldsnumber(Re)36Dimensionless NumbersReduces tDimensionlessNumbersLaminar flow regimeTurbulent flow regimeExperimental values of CD for spheres in fluid flows at various Re37Dimensionless NumbersLaminar fBoundaryLayergasvelocityFrictional forces against reactor walls decrease gas velocity The boundary layer thickness can be estimated from:38Boundary Layer gas velocityFBoundaryLayer-temperatureContact with hot surfaces increases temperature39Boundary Layer-temperatureCoBoundaryLayerprecursorconcentrationDepletion of precursor decreases gas phase concentration40Boundary Layer precursor conNucleationandGrowthVan der Waals type adsorption of precursor to substratePrecursors then diffuse across surfacePrecursors diffuse across boundary layer to surfaceAnd can be desorbed back into main gas flowOr can find low energy binding sites to coalesce into filmMain Gas Flow41Nucleation and GrowthVan der WNucleationandGrowthSubstrate TemperatureGrowth RateSurface DiffusionCrystallinityLowHighSlowrelativefluxofprecursorsAmorphousnocrystallinestructureHighLowFastrelativetofluxofprecursorsEpitaxialreplicatessubstratestructureIntermediateIntermediateIntermediatePolycrystalline42Nucleation and GrowthSubstrateGrowthMechanisms(b)Frank-van der MerweLayer growth(c)Stranski-KastanovMixed layered and island growth(a)Volmer-WeberIsland growth43Growth Mechanisms(b)Frank-vThinFilmAnalysisManytechniquesareusedtocharacterisethinfilmsExamplesincludeXRDcrystallinity,phaseXRRlayerthickness,layerroughnessSEM/EDX/WDXmorphology,thickness,compositionRamanphase,bondingFTIRphase,bondingXPScomposition,depthprofiling,dopingSIMScomposition,depthprofiling,dopingAFMroughness,surfacemorphologyTEMcrystallinestructure,crystaldefectsAnalysisoffunctionalproperties44Thin Film AnalysisMany techniqCVDonGlassForon-linecoatingofglasswerequire:Highgrowthratesrequiredthicknessin100nm/spossibleLowprecursorefficiency10%SiCxOy(70 nm)SnO2:F(350 nm)GlassSiH4+C2H4+CO2SiCxOy+H2O+otherby-productsUsedascoloursuppressionandbarrierlayer57CVD of SnO2:FSnCl4+H2O+HF LowEmissivityCoatingGenerallybasedonSnO2:F(TransparentConductiveOxide)SiCOunderlayerusedascoloursuppressant58Low Emissivity CoatingGenerallLow-EandSolarControlCoatings59Low-E and Solar Control CoatinSelf-CleaningGlassTwomechanisms:SuperhydrophilicityPhotocatalyticdegradationoforganicmatter.TiO2coating60Self-Cleaning GlassTwo mechaniSuperhydrophilicityOxygen vacanciesTiO-TiOTiHTiTiTiH+TiOTiOTiTiOTiOTiHHH2O(OH-,H+)Water dropletsUniform water filmUV illumination timeContact angleooooooodarkUV61SuperhydrophilicityOxygen vacaPhotocatalyticActivityUltrabandgapirradiationofTiO2GenerationofelectronholeinvalencebandHolemigratestothesurfaceandresultsinoxidationoforganicmaterialValenceBandConductanceBandOxidationReductionAA+BB-h+hn62Photocatalytic ActivityUltra bSemi-conductorPhotocatalysisA.Mills,S Le Hunte,J.Photochem.Photobiol A,2019,108,1-35.63Semi-conductor PhotocatalysisACVDofActivTMSiO2(30 nm)TiO2(17 nm)GlassSiH4+O2+C2H4 SiO2+by-productsUsed as barrier layer to prevent diffusion of Na ions into TiO2 layerTiCl4+EtOAc TiO2+HCl+organic by-productsLaminar Flow regimeReasonable growth rates and precursor efficiency64CVD of ActivTMSiO2(30 nm)TiO2ActivTM65ActivTM65ActivTM66ActivTM66ActivTM67ActivTM67Superhydrophilicity15 mins UV Exposure30 mins UV Exposure45 mins UV ExposureBefore UV Exposure68Superhydrophilicity15 mins UV PhotocatalyticEffect UV-AbsorptionO2-OH*Organic SoilHH2 2O+COO+CO2 2GlassBarrier LayerTiO2-Layer69Photocatalytic Effect UV-AbsoPhotocatalyticEffectThephotoactivityofthecoatingcanbemeasuredbymonitoringthedecompositionofastandardcontaminantAthinfilmofstearicacid(n-octadecanoicacid,200)isappliedfromamethanolsolutionontothecoatingStearicacidusedasatypicalorganiccontaminantFTIR(Fouriertransforminfra-redspectroscopy)usedtodetectC-HstretchofstearicacidC-HabsorptionintensitymeasuredaftervaryingUVexposure70Photocatalytic EffectThe photoStearicAcidDecompositionC-HAbsorptionZeroUVexposureC-HAbsorption60minsUVexposureUV 0.77W/m2 340nm71Stearic Acid DecompositionC-H PilkingtonActivTM72Pilkington ActivTM72SummaryScaleoftheGlobalFlatGlassIndustryManufacturingFlatGlassFloatGlassProcessCoatingGlassChemicalVapourDepositionExamplesofcommercialglazingcoatingspreparedbyCVD73SummaryScale of the Global FlaRecommendedReadingD.W.SheelandM.E.PembleAtmospheric Pressure CVD Coatings on Glass,ICCG42019 cvdtechnologies.co.uk/CVD%20on%20Glass.pdfM.L.Hitchman,K.F.JensenChemical Vapor DepositionAcademicPress,1993W.S.Rees,CVD of Non-metals,VCH,Weinheim,2019M.OhringThe Materials Science of Thin Films,AcademicPress,2019pilkington74Recommended ReadingD.W.Sheel First in Glass75First in Glass75ENDEND
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