Pilkington浮法玻璃生产介绍

1、A member of NSG Group.Application of Inorganic Chemistry in IndustryFlat Glass and Coatings On GlassDr Troy ManningAdvanced Technologist, On-line CoatingsPilkington European Technical CentreHall LaneLathomUKtroy.manningpilkington.OutlineOverview of Flat Glass industry and NSG/PilkingtonFlat Glass ma

2、nufactureFloat Glass ProcessCoating technology within the glass industryChemical Vapour DepositionExamples of on line coating applicationsLow Emissivity/Solar ControlSelf CleaningSummarySuggested Reading.Global Flat Glass MarketGlobal Market 37 million tonnes (4.4 billion sq. m)Building Products 33

3、m tonnes - Automotive 4m tonnesOf which24 million = high quality float glass3 million = sheet2 million = rolled8 million = lower quality float (mostly China)Global Value At primary manufacture level 15 billionAt processed level 50 billion.NSG and Pilkington combinedA global glass leader the pure pla

4、y in Flat GlassCombined annual sales c. 4 billionEqual to Asahi Glass in scale, most profitable in Flat GlassOwnership/interests in 46 float lines6.4 million tonnes annual outputWidened Automotive customer base36,000 employees worldwideManufacturing operations in 26 countriesSales in 130+ countries.

5、Manufacture of Flat GlassFour main methodsPlate Glass (1688) molten glass poured on to a flat bed, spread, cooled and polishedSheet Glass (1905) continuous sheet of glass drawn from tank of molten glassRolled Glass (1920) molten glass poured onto to two rollers to achieve an even thickness, making p

6、olishing easier. Used to make patterned and wired glass.Float Glass (1959) molten glass poured onto bed of molten tin and drawn off in continuous ribbon. Gives high quality flat glass with even thickness and fire polish finish. 320 float-glass lines worldwide.Melting furnaceFloat bathCooling lehrCon

7、tinuos ribbon of glassCross cuttersLarge plate lift-off devicesSmall plate lift-off devicesRaw material feedThe Float-Glass ProcessOperates non-stop for 10-15 years6000 km/year0.4 mm-25 mm thick, up to 3 m wide.The Float Glass Process.Raw materials.Melting Furnace.Float Bath.Float Glass Plant.The Fl

8、oat-Glass ProcessFine-grained ingredients, closely controlled for quality, are mixed to make batch, which flows as a blanket on to molten glass at 1500 C in the melter. The furnace contains 2000 tonnes of molten glass.After about 50 hours, glass from the melter flows gently over a refractory spout o

9、n to the mirror-like surface of molten tin, starting at 1100C and leaving the float bath as a solid ribbon at 600C. Despite the tranquillity with which float glass is formed, considerable stresses are developed in the ribbon as it cools. .Raw MaterialsOxide % in glass Raw material sourceSiO272.2Sand

10、Na2O13.4Soda Ash (Na2CO3)CaO8.4Limestone (CaCO3)MgO4.0Dolomite (MgCO3.CaCO3)Al2O31.0Impurity in sand, Feldspar or CalumiteFe2O30.11Impurity in sand or Rouge (Fe2O3)SO30.20Sodium sulphateC0.00Anthracite.Raw materials SiO2Very durable, BUT high melting point (1700C)!+ Na2OMelts at a lower temperature,

11、 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 customer.Chemistry of GlassImportant glassmaking chemistry: basic reac

12、tionsNa2CO3 + SiO2 1500C Na2SiO3 + CO2Na2SiO3 + x SiO2 Na2SO4 (Na2O)(SiO2)(x+1)Digestion.Composition of Glass.Structure of GlassRandom 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 cry

13、stallisation .Body-tinted GlassIonResulting Colour of GlassFerrous (Fe2+)BlueFerric (Fe3+)YellowFe2+ + Fe3+GreenSelenium (SeO2)BronzeCobalt (Co2+)Grey/BlueNickel (Ni2+)Grey.CIE L a* b* colour space.CIE L a* b* colour space.Functions of a WindowLight in homes, officesLight out shops, museum displaysH

14、eat in heating dominated climatesHeat out cooling dominated climatesCan change properties of glass by applying coatings to the surface.Making a window functional - coatingsA wide variety of coating technologies are utilised by the glass industrySpray PyrolysisPowder SprayChemical Vapour DepositionSp

15、utter CoatingThermal Evaporation CoatingsSol Gel CoatingsThese are appliedOn Line i.e. as the glass is produced on the float lineOff Line i.e. coating not necessarily produced at the same location.Variations of CVDAtmospheric Pressure APCVDLow Pressure - LPCVDAerosol Assisted - AACVD Metalorganic MO

16、CVDCombustion/Flame CCVDHot Wire/Filament HWCVD/HFCVDPlasma Enhanced - PECVDLaser Assisted LACVDMicrowave Assisted MWCVDAtomic Layer Deposition ALD.Chemical Vapour Deposition.Chemical Vapour DepositionMain gas flow regionGas Phase ReactionsSurface DiffusionDesorption of Film PrecursorBy ProductsDiff

17、usion to surface.Chemical Vapour DepositionAnimation kindly supplied by Dr. Warren Cross, University of Nottingham.CVD processes and parametersProcessParametersTransportPrecursorsGas phase reactionPressure, temperature, flow conditions, boundary layer thickness, gas phase concentration, precursors,

18、carrier gasDiffusionPressure, temperature, flow conditions, boundary layer thickness, gas phase concentrationAdsorptionTemperature, gas phase concentration, number and nature of sitesSurface reactionTemperature, nature of surfaceDesorption of by-productsTemperature, pressure, nature of surfaceDiffus

19、ion to lattice siteTemperature, surface mobility, number of vacant sites.CVD Precursor PropertiesVolatile gas, liquid, low melting point solid, sublimable solidPureStable under transportReact/Decompose cleanly to give desired coating minimise contaminantsCan be single source or dual/multi-source.CVD

20、 PrecursorsSingle Source pyrolysis (thermal decomposition) e.g Ti(OC2H5)4 TiO2 + 4C2H4 + 2H2O (400 C)Oxidation e.g SiH4(g) + O2(g) SiO2(s) + 2H2(g)Reduction e.g. WF6(g) + 3H2(g) W(s) + 6HF(g)Dual source e.g. TiCl4(g) + 4EtOH(g) TiO2(s) + 4HCl(g) + 2EtOEt(g).Dual Source and Single Source PrecursorsFi

21、lmDual SourceSingle SourceGaAsGaCl3 + AsH3Me2Ga(AsH2)TiNTiCl4 + NH3Ti(NMe2)4WSiWCl6 + SiH4W(SiR)4TiO2TiCl4 + H2OTi(OiPr)4CdSeCdMe2 + H2SeCd(SeR)2.Transport of PrecursorsBubbler for liquids and low melting solids Direct Liquid Injection syringe and syringe driver for liquids and solutions Sublimation

22、 for solids hot gas passed over heated precursorAerosol of precursor solutions.Effect of Temperature on Growth RateIndependent of temperature.Flow conditionsLaminar Flow regimeTurbulent Flow Regime.Reynolds NumberDimensionless number describing flow conditionsr = Mass density related to concn and pa

23、rtial pressureu = average velocity= viscosityL = relevant length, related to reactor dimensionsIf Re 1000 fully turbulent flowReality is between the two extremes.Dimensionless NumbersReduces the number of parameters that describe a systemMakes it easier to determine relationships experimentallyFor e

24、xample: Drag Force on a SphereVariables: Force = f (velocity, diameter, viscosity, density)Can be reduced to 2 “dimensionless groups:Drag coefficient (CD) and Reynolds number (Re).Dimensionless NumbersLaminar flow regimeTurbulent flow regimeExperimental values of CD for spheres in fluid flows at var

25、ious Re.Boundary Layer gas velocityFrictional forces against reactor walls decrease gas velocity The boundary layer thickness can be estimated from:.Boundary Layer - temperatureContact with hot surfaces increases temperature.Boundary Layer precursor concentrationDepletion of precursor decreases gas

26、phase concentration.Nucleation and GrowthVan 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 Flow.

27、Nucleation and GrowthSubstrate TemperatureGrowth RateSurface DiffusionCrystallinityLowHighSlow relative flux of precursorsAmorphous no crystalline structureHighLowFast relative to flux of precursorsEpitaxial replicates substrate structureIntermediateIntermediateIntermediatePolycrystalline.Growth Mec

28、hanisms(b) Frank - van der MerweLayer growth(c) Stranski - KastanovMixed layered and island growth(a) Volmer - WeberIsland growth.Thin Film AnalysisMany techniques are used to characterise thin filmsExamples includeXRD crystallinity, phaseXRR layer thickness, layer roughnessSEM/EDX/WDX morphology, t

29、hickness, compositionRaman phase, bondingFTIR phase, bondingXPS composition, depth profiling, dopingSIMS composition, depth profiling, dopingAFM roughness, surface morphologyTEM crystalline structure, crystal defectsAnalysis of functional properties.CVD on GlassFor on-line coating of glass we requir

30、e:High growth rates required thickness in 100 nm/s possibleLow precursor efficiency 10%SiCxOy (70 nm)SnO2:F (350 nm)GlassSiH4 + C2H4 + CO2 SiCxOy + H2O + other by-productsUsed as colour suppression and barrier layer.Low Emissivity CoatingGenerally based on SnO2:F (Transparent Conductive Oxide)SiCO u

31、nder layer used as colour suppressant.Low-E and Solar Control Coatings.Self-Cleaning GlassTwo mechanisms:Super hydrophilicityPhotocatalytic degradation of organic matter.TiO2 coating.SuperhydrophilicityOxygen vacanciesTiO-TiOTiHTiTiTiH+TiOTiOTiTiOTiOTiHHH2O(OH-, H+)Water dropletsUniform water filmUV

32、 illumination timeContact angleooooooodarkUV.Photocatalytic ActivityUltra band gap irradiation of TiO2 Generation of electron hole in valence bandHole migrates to the surface and results in oxidation of organic materialValence BandConductance BandOxidationReductionAA+BB-h+hn.Semi-conductor Photocata

33、lysisA. Mills, S Le Hunte, J. Photochem. Photobiol A, 1997, 108, 1-35.CVD of ActivTMSiO2 (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 efficiency.ActivTM.ActivTM.ActivTM.Superhydrophilicity15 mins UV Exposure30 mins UV Exposure45 mins UV ExposureBefore UV Exposure.Photocatalytic Effect UV-AbsorptionO2 -OH*Organic SoilH2O + CO2GlassBarrier L