1、1A member of NSG Group2Application of Inorganic Chemistry in IndustryFlat Glass and Coatings On GlassDr Troy ManningAdvanced Technologist, On-line CoatingsPilkington European Technical CentreHall LaneLathomUKtroy.manningpilkington3OutlineOverview of Flat Glass industry and NSG/PilkingtonFlat Glass m
2、anufactureFloat Glass ProcessCoating technology within the glass industryChemical Vapour DepositionExamples of on line coating applicationsLow Emissivity/Solar ControlSelf CleaningSummarySuggested Reading4Global Flat Glass MarketGlobal Market 37 million tonnes (4.4 billion sq. m)Building Products 33
3、 m tonnes - Automotive 4m tonnesOf which 24 million = high quality float glass 3 million = sheet 2 million = rolled 8 million = lower quality float (mostly China)Global Value At primary manufacture level 15 billionAt processed level 50 billion5NSG and Pilkington combinedA global glass leader the pur
4、e play 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+ count
5、ries6Manufacture of Flat Glass Four main methods Plate Glass (1688) molten glass poured on to a flat bed, spread, cooled and polished Sheet Glass (1905) continuous sheet of glass drawn from tank of molten glass Rolled Glass (1920) molten glass poured onto to two rollers to achieve an even thickness,
6、 making polishing 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 worldwide7Melting furnaceFloat bathCooli
7、ng lehrContinuos 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 wide8The Float Glass Process9Raw materials10Melting Furnace11Float Bath12Float Glass
8、 Plant13The Float-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 refr
9、actory spout on 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. 14Raw MaterialsOxide % in glass Raw material sou
10、rceSiO272.2SandNa2O13.4Soda Ash (Na2CO3)CaO8.4Limestone (CaCO3)MgO4.0Dolomite (MgCO3.CaCO3)Al2O31.0Impurity in sand, Feldspar or CalumiteFe2O30.11Impurity in sand or Rouge (Fe2O3)SO30.20Sodium sulphateC0.00Anthracite15Raw materials SiO2Very durable, BUT high melting point (1700C)!+ Na2OMelts at a lo
11、wer 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 customer16Chemistry of GlassImportant glassmaking chem
12、istry: basic reactionsNa2CO3 + SiO2 1500C Na2SiO3 + CO2Na2SiO3 + x SiO2 Na2SO4 (Na2O)(SiO2)(x+1)Digestion17Composition of Glass18Structure 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 com
13、plex to prevent crystallisation 19Body-tinted GlassIonResulting Colour of GlassFerrous (Fe2+)BlueFerric (Fe3+)YellowFe2+ + Fe3+GreenSelenium (SeO2)BronzeCobalt (Co2+)Grey/BlueNickel (Ni2+)Grey20CIE L a* b* colour space21CIE L a* b* colour space22Functions of a Window Light in homes, offices Light ou
14、t shops, museum displays Heat in heating dominated climates Heat out cooling dominated climates Can change properties of glass by applying coatings to the surface23Making a window functional - coatings A wide variety of coating technologies are utilised by the glass industry Spray Pyrolysis Powder S
15、pray Chemical Vapour Deposition Sputter Coating Thermal Evaporation Coatings Sol Gel Coatings These are applied On Line i.e. as the glass is produced on the float line Off Line i.e. coating not necessarily produced at the same location24Variations of CVD Atmospheric Pressure APCVD Low Pressure - LPC
16、VD Aerosol Assisted - AACVD Metalorganic MOCVD Combustion/Flame CCVD Hot Wire/Filament HWCVD/HFCVD Plasma Enhanced - PECVD Laser Assisted LACVD Microwave Assisted MWCVD Atomic Layer Deposition ALD25Chemical Vapour Deposition26Chemical Vapour DepositionMain gas flow regionGas Phase ReactionsSurface D
17、iffusionDesorption of Film PrecursorBy ProductsDiffusion to surface27Chemical Vapour DepositionAnimation kindly supplied by Dr. Warren Cross, University of Nottingham28CVD processes and parametersProcessParametersTransportPrecursorsGas phase reactionPressure, temperature, flow conditions, boundary l
18、ayer thickness, gas phase concentration, precursors, 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-p
19、roductsTemperature, pressure, nature of surfaceDiffusion to lattice siteTemperature, surface mobility, number of vacant sites29CVD Precursor Properties Volatile gas, liquid, low melting point solid, sublimable solid Pure Stable under transport React/Decompose cleanly to give desired coating minimise
20、 contaminants Can be single source or dual/multi-source30CVD Precursors Single 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)
21、+ 4HCl(g) + 2EtOEt(g)31Dual Source and Single Source PrecursorsFilmDual SourceSingle SourceGaAsGaCl3 + AsH3Me2Ga(AsH2)TiNTiCl4 + NH3Ti(NMe2)4WSiWCl6 + SiH4W(SiR)4TiO2TiCl4 + H2OTi(OiPr)4CdSeCdMe2 + H2SeCd(SeR)232Transport of Precursors Bubbler for liquids and low melting solids Direct Liquid Injecti
22、on syringe and syringe driver for liquids and solutions Sublimation for solids hot gas passed over heated precursorAerosol of precursor solutions4 .24)760( ppVFVa33Effect of Temperature on Growth Rate1/TGrowth rateKinetic regimeMass transport regimeRTEAka lnlnIndependent of temperature34Flow conditi
23、onsLaminar Flow regimeTurbulent Flow Regime35Reynolds Number Dimensionless number describing flow conditionsuLRe Mass density related to concn and partial pressureu = average velocity= viscosityL = relevant length, related to reactor dimensionsIf Re 1000 fully turbulent flowReality is between the tw
24、o extremesforces viscous fluidforces inertial fluid36Dimensionless Numbers Reduces the number of parameters that describe a system Makes it easier to determine relationships experimentally For example: Drag Force on a SphereVariables: Force = f (velocity, diameter, viscosity, density)Can be reduced
25、to 2 “dimensionless groups”:Drag coefficient (CD) and Reynolds number (Re)228 uLFCD uLRe37Dimensionless NumbersLaminar flow regimeTurbulent flow regimeExperimental values of CD for spheres in fluid flows at various Re38Boundary Layer gas velocityFrictional forces against reactor walls decrease gas v
26、elocity 2132 uLLd The boundary layer thickness can be estimated from:39Boundary Layer - temperatureContact with hot surfaces increases temperature40Boundary Layer precursor concentrationDepletion of precursor decreases gas phase concentration41Nucleation and GrowthVan der Waals type adsorption of pr
27、ecursor 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 Flow42Nucleation and GrowthSubstrate TemperatureGrowth RateSurface DiffusionCryst
28、allinityLowHighSlow relative flux of precursorsAmorphous no crystalline structureHighLowFast relative to flux of precursorsEpitaxial replicates substrate structureIntermediateIntermediateIntermediatePolycrystalline43Growth Mechanisms(b) Frank - van der MerweLayer growth(c) Stranski - KastanovMixed l
29、ayered and island growth(a) Volmer - WeberIsland growth44Thin Film Analysis Many techniques are used to characterise thin films Examples include XRD crystallinity, phase XRR layer thickness, layer roughness SEM/EDX/WDX morphology, thickness, composition Raman phase, bonding FTIR phase, bonding XPS c
30、omposition, depth profiling, doping SIMS composition, depth profiling, doping AFM roughness, surface morphology TEM crystalline structure, crystal defects Analysis of functional properties45CVD on GlassFor on-line coating of glass we require: High growth rates required thickness in 100 nm/s possible
31、 Low precursor efficiency 10%SiCxOy (70 nm)SnO2:F (350 nm)GlassSiH4 + C2H4 + CO2 SiCxOy + H2O + other by-productsUsed as colour suppression and barrier layer58Low Emissivity Coating Generally based on SnO2:F (Transparent Conductive Oxide) SiCO under layer used as colour suppressant59Low-E and Solar
32、Control Coatings60Self-Cleaning GlassTwo mechanisms:Super hydrophilicityPhotocatalytic degradation of organic matter.TiO2 coating61SuperhydrophilicityOxygen vacanciesTiO-TiOTiHTiTiTiH+TiOTiOTiTiOTiOTiHHH2O(OH-, H+)Water dropletsUniform water filmUV illumination timeContact angleooooooodarkUV62Photoc
33、atalytic 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+h63Semi-conductor PhotocatalysisA. Mills, S Le Hunte, J. Photochem. Photobiol
34、A, 2019, 108, 1-35.64CVD 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 efficiency65ActivTMReference
35、Pattern (black vertical lines) = Anatase TiO2 (ICDD Pattern 21-1272)66ActivTM67ActivTM68Superhydrophilicity15 mins UV Exposure30 mins UV Exposure45 mins UV ExposureBefore UV Exposure69Photocatalytic Effect UV-AbsorptionO2 -OH*Organic SoilGlassBarrier LayerTiO2 - Layer70Photocatalytic Effect The phot
36、oactivity of the coating can be measured by monitoring the decomposition of a standard contaminant A thin film of stearic acid (n-octadecanoic acid, 200) is applied from a methanol solution onto the coating Stearic acid used as a typical organic contaminant FTIR (Fourier transform infra-red spectros
37、copy) used to detect C-H stretch of stearic acid C-H absorption intensity measured after varying UV exposureOO71Stearic Acid Decomposition 0.000 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016 0.018 0.020 0.022 0.024 0.026 0.028 0.030 0.032 0.034 0.036 0.038Absorbance 2790 2800 2810 2820 2830 2840 2
38、850 2860 2870 2880 2890 2900 2910 2920 2930 2940 2950 2960 Wavenumbers (cm-1)C-H Absorption Zero UV exposureC-H Absorption 60 mins UV exposureUV 0.77W/m2 340nm72Pilkington ActivTM73Summary Scale of the Global Flat Glass Industry Manufacturing Flat Glass Float Glass Process Coating Glass Chemical Vap
39、our Deposition Examples of commercial glazing coatings prepared by CVD74Recommended Reading D.W. Sheel and M.E. Pemble Atmospheric Pressure CVD Coatings on Glass, ICCG4 2019 cvdtechnologies.co.uk/CVD%20on%20Glass.pdf M.L. Hitchman, K.F. Jensen Chemical Vapor Deposition Academic Press, 1993 W.S. Rees, CVD of Non-metals, VCH, Weinheim, 2019 M. Ohring The Materials Science of Thin Films, Academic Press, 2019 pilkington75First in Glass谢谢你的阅读v知识就是财富v丰富你的人生
