2017年武汉理工材料学院复试版学硕专硕通用3月25日第五次后专业英语概论

IntroductiontoMaterialsCh.4,

Glass武汉理工大学材料科学与工程学院《材料概论》IntroductiontoMaterials12Mosttime,wedidnotrealizeCanyoucounthowmanythingsinthisclassroomthataremadefromglass?3Wesee4Wedidnotsee5GlassissoimportanttousSo,Whatistheglassconstitutedof?

(玻璃的主要组份)Howistheglassclassified?(玻璃的分类)Howistheglassworkmade?(玻璃的制备方法)Whatarethepropertiesofglass?(玻璃的性质)Whatisthestructureofglass?(玻璃的结构)Whatarethemajorapplicationsofglass?(玻璃的主要用途)Newtypesofglassandnewapplications?(新型玻璃和玻璃的新用途)6ContentsTheworldofglassPreparationofglassStructureandpropertiesApplicationsofglassOptoelectronicsmaterials

(光电材料)1.掌握玻璃的主要类型2.了解玻璃的主要用途3.学习玻璃的生产工艺4.熟悉玻璃的结构和性质5.了解光电转换材料的最新进展课程学习目的7PartI:TheworldofglassSection1.1:Introduction8Definitionofglass

玻璃的定义Glassisaninorganicproductoffusionwhichhascooledtoarigidconditionwithoutcrystallization—ASTM1949熔体在冷却过程中粘度逐渐增大而得的不结晶的固体材料。—

汉语大词典9Featuresofglass

玻璃的通性Lackoftheperiodic(longrange)orderofacrystalInfiniteunitcell(norepeatinglargescalestructures)3DnetworklackingsymmetryandperiodicityISOTROPIC各向同性:samepropertiesinalldirectionsMetastability介稳性能Comparedtoitscrystallineform无固定熔点

(nofixedmeltingtemp.)Canbeeithersolidorliquid/viscosity(粘度)性质变化的连续性与可逆性Continuousandreversible(可逆的)changes10Naturalglass(1)Thevolcanicoutflow(火山喷发)ofthemoltenmagma(岩浆)getcooledandformglasses.11Naturalglass(2)Impactites(击变岩)arenaturalglassesformedfromcrystallinematerialsrenderedamorphousbytheshockofmeteoric(陨石)impact.Glassesformedfromimpactedmeltsareknownastektites(玻陨石).12Majorapplicationsofindustrialglass

工业玻璃的主要用途Nowcommonlyappliedfor:Containers(容器)WindowsDecorationLenses(镜头)Fiberglass(玻璃纤维)Fiberoptics(光导纤维)RoadsignsComposites13AbriefhistoryofglassAccordingtothemethodsofthemanufacturingprocess:TheFirstPeriod:1700BCthrough100ADPrimitivemethodofmakingglassusingmolds.TheSecondPeriod:100ADthrough400-500ADGlassblowingtechniquediscovered,andglassmanufactureesamorepracticalprocess.TheThirdPeriod:400-500AD~1200ADMiddleAges,characterizedbyByzantineglass.TheFourthPeriod:1200AD~1900ADVenetianglass,foundationformodernglassmakingisset.TheFifthPeriod:1900AD~presentGlassobjectsusedaseverydaygoods;largescalemanufacturing.14玻璃历史的简短介绍人类应用玻璃的历史根据生产工艺的不同可以分为以下几个阶段:

公元前1700到公元后100年用模子进行原始的玻璃生产公元100年到400-500人类发明了吹制玻璃的工艺400-500到1200欧洲的中世纪，拜占庭玻璃占据主流地位1200AD到1900威尼斯玻璃工艺占据主导地位，现代玻璃制造工业开始成形1900AD到现在玻璃成为日用品原材料的一种，大规模工业化生产日益普遍15GreateventsinthehistoryofglassDate PlaceandActivity650BC 1stGlassmakinghandbook1,200AD Veniceglasscenterdominatesinglassproduction1,590 GlasstelescopeandmicroscopelensesaredevelopedinNetherlandsandusedforthefirsttime1,609 GalileoGalileiusestelescopetoinvestigateplanetarymotion16Greateventsinthehistoryofglass1,665 HallofmirrorsinVersaillesisbuilt17Greateventsinthehistoryofglass1875 TechnicalglassesaredevelopedinGermanybyCarlZeissatJena,Germanyesamajorglassscienceandengineeringcenter.1926 ArthurWoodandDavidGrayofCorningGlassWorksdevelopthe“399”machine,latercalledthe“Ribbon”machinetomakelightbulbsatspeedsof1000perminute.18Greateventsinthehistoryofglass1932 WilliamZachariasenpublishesthe“RandomNetworkHypothesis”ofglassstructureandhisrulesofglassformationinJ.Amer.Chem.Society1959 PilkingtonBrotherspatentthefloatglass processandintroducedinEnglandandwillultimatelyrevolutionizeflatglassmanufacturing.1970 1stsilicaopticalfiberproducedatCorningGlassWorksusingchemicalvapordepositiontechniquestoreduceattenuation(衰减)andimprovesignaltransmission19Classificationofglassesaccordingtocompositions

玻璃的分类:按成份分OxideglassesChalcogenideGlasses(硫属化物玻璃)Thioborateglasses(B2S3)(硫硼玻璃)Halideglasses(BeF2,ZnCl2etc.)(卤化物玻璃)Heavymetalfluorideglasses(ZrF4)(重金属氟化玻璃)Oxy-halideglasses(氧卤玻璃)Oxynitrideglasses(氧氮玻璃)Metallicglasses(金属玻璃)Glass-likeCarbon(玻璃碳)特种玻璃是指除日用玻璃以外的、采用精制、高纯或新型原料，或采用新工艺在特殊条件下或严格控制形成过程制成的一些具有特殊功能或特殊用途的玻璃，也包括经玻璃晶化获得的微晶玻璃。（1）使玻璃具有特殊的功能；（2）将常规特性发挥至极点；（3）将上述某项特性以另一种特性置换；（4）牺牲上述某些性能而赋予某项有用的特性。20OxideglassMorethan90%oftheglassinuseisbasedonoxidesandinparticularsilica.Silicaandsilicateglasses(硅酸盐玻璃）B2O3andborateglasses(硼酸盐玻璃）GeO2andgermanateglasses（锗酸盐玻璃）P2O5andphosphateglasses（磷酸盐玻璃）Complexoxideglasses21CommonoxideglassesVitreousSilica-SiO2Composition:SiO2VeryexpensiveUses:LowexpansionchemicallyresistanttubingLightbulbswhereUVtransparencyand hightemperaturelimitisnecessaryUltra-lowlossmunicationopticalfiberLowexpansionmirrorsandmirrorblanks22CommonoxideglassesSoda-Lime-SilicateGlass(钠钙玻璃)Composition:10-15Na2O+5-15CaO+50-70SiO2Uses: Windows,bottles,containers,fibers,mirrors,lenses,tableware,lightbulbs,etc.23CommonoxideglassBoratesilicateglass(硼硅玻璃)Composition:SiO2+B2O3+Al2O3+Na2O+K2OUses:Pyrexglass(派勒克斯耐热玻璃)ChemicallaboratoryequipmentCookwareLightingSpecialwindows.24ClassificationofglassaccordingtoapplicationsPlateglassGenerallyplateglasscomesintwothicknesses,¼inchand1/8inch.Canbepolishedorfloatglass.Temperedglass(钢化玻璃)Heatedonbothsidesandcooledrapidlywithastreamofair.Thiscausestheoutsidetocompressrapidlyandplacetensionontheinsideoftheglass.Approximatelyfourtimesstrongerthanuntemperedglass.Breaksinsmallpieces.Usedforcarwindows,showerdoors,windowsinpublicbuildings.Laminatedglass(夹层玻璃)Madebyplacingapieceofplasticbetweentwolayersofglass.Mainuseisforwindshieldsandbulletproofglass.ContainerglassBlownat600–800celsius.ContainverylittleironRefractiveindexcanvaryfromtoptobottomofbottle.Annealingwillraisetherefractiveindex25PartII:PreparationofGlassesSection2.1:Introduction26GlassManufacturingFourMarketSegmentsContainerGlassFloat(FlatGlass)FiberGlassSpecialGlass27KeyFactorsAffectingtheGlassIndustryTechnologyAdvances ManufacturingadvancesNewproductadvancesEnvironmentalRegulations NOx,SOxregulationsIndustryRestructuringPlantandManufacturersmergersEnergycostsandavailabilitySource,purity,costs,regulationetc.28SchemeofcommonglassproductionMaterialproportioningBatchmixingMeltingFiningCoolingDistributingFormingAnnealingInspectionPackingandshipping29ChemicalNatureofGlassFormingMaterialsGlasseshavebeenmadefromelements,simplechemicalcompounds,complexorganicmolecules,saltmixturesandalloys.RoleofoxidesinglassGlassformers:B2O3,SiO2,GeO2,P2O5,Al2O3Intermediates:TiO2,ZnO,PbOGlassmodifiers:Li2O,Na2O,K2O,MgOCaOThekeyfactorinthepreparationofglassesishowfastthemeltcanbequenched.30QuestionWilloxidesbelowformglass?65%CaO+20%Na2O+15%MgO31辅助原料是使玻璃获得某些必要性质和加速熔制过程的原料，根据作用的不同，分为：澄清剂：加入玻璃配合料或玻璃熔体中，在高温下分解或气化形成气体以促进玻璃液中气泡排除的物质。助熔剂：能促使玻璃熔制过程加速的原料。着色剂：是使玻璃着色的物质。根据着色剂在玻璃中呈现的状态，可分为离子着色剂，硫、硒化合物类分子着色剂和金属胶体着色剂三大类。脱色剂：是指能减弱铁及其它杂质离子或化合物对玻璃着色影响的物质。主要是消除Fe2+的着色。又分为物理脱色剂和化学脱色剂两大类。乳浊剂：是指在玻璃中的溶解度不大，随着温度下降，重新以微粒状从玻璃中析出，使玻璃产生乳浊现象的物质。氧化剂及还原剂：是在熔制玻璃时能释放出或夺取氧的物质。可以形成氧化或还原的熔制条件。32对混合料的质量要求保证配合料的质量要求是加速玻璃熔制和提高玻璃质量，防止产生缺陷的基本措施，对配合料的主要要求是：构成配合料的各种原料均应有一定的粒度组成，即同一种原料应有适宜的粒度，不同原料间保持一定的粒度比，以保证配合料的均匀度、熔制速度、玻璃液均匀度，提高混合质量，防止配合料的分层。配合料中应具有一定水分，使水在石英颗粒原料表面上形成水膜，5%的纯碱和芒硝溶于水膜中，有助于加速熔化。为了有利于玻璃液的澄清和均化，配合料需有一定的气体率。对钠钙硅酸盐玻璃，气体率为15%～20%。必须混合均匀，以保证玻璃液的均匀性。33MeltingofglassTheprocessoffiringthepre-mixedadmixtureofrawmaterialsandformingthehomogenousglassmelt.MeltingofglassisacomplexprocessinvolvingaserialofphysicalandchemicalchangesTheresultofthesechangesistoturntherawmaterialsintoacomplexglassmeltThemeltingprocessofglasscanbedividedintofivestagescalled:formationofsilicates,melting,fining,homogenization(均化)andcooling.34StructuralapproachtoglassformationGlassFormationresultswhenLiquidsarecooledtobelowTgsufficientlyfasttoavoidcrystallizationNucleationofcrystallineseedsareavoidedGrowthofNucleiintocrystallites(crystals)isavoidedLiquidis“frustrated”byinternalstructurethathindersbothevents35Formingofglass

玻璃的成形与定形玻璃的成形是指熔融的玻璃液转变为具有固定几何形状制品的过程。玻璃必须在一定的温度范围内才能成形。在成形时，玻璃液除作机械运动之外，还同周围介质进行连续热传递。由于冷却和硬化，玻璃首先由粘性液态转变为可塑态，然后再转变脆性固态。因此，玻璃的成形过程是极其复杂的多种性质不同作用的综合。其中，机械的和热的作用具有重要的意义。玻璃制品的成形过程和其它塑性材料相同，分为成形和定形两个阶段。第一阶段是赋予制品一定的几何形状，第二阶段是把制品的形状固定下来，玻璃的成形和定形是连续进行的，定形实际是成形的延续。定形所需要的时间比成形时间要长。决定成形阶段的因素：流变性，即粘度表面张力弹性及其与温度的变化特征决定定形阶段的因素：热性质硬化速度36MajorformingtechniquesBlowing吹制法Compression压制法Drawing拉制法Floatingmethod浮法

→floatglassRolling压延法Casting浇铸法37FormingofglasswithblowingmethodsuspendedParisonFinishingmoldCompressedair38Formingofglasswithblowingmethod39FormingofglasswithcompressionmethodGob（滴料）ParisonmoldPressingoperation40ProductionofglassplatesOriginally,glassplatesmadeoneatatimeusingthePittsburghprocess(verticallydrawacontinuoussheetofglassofaconsistentwidthfromthetank).41ProductionoffloatglassOriginallyabletomakeonly6mmthickglass,nowmadeasthinas0.4mmandasthickas25mm.Therearearound260floatplantsworldwidewithacombinedoutputofabout800,000tonnesofglassaweek.Afloatplant,whichoperatesnon-stopforbetween11-15years,makesaround6000kilometresofglassayear.42ThefloatingpartMoltenglass,atapproximately1000ºC,ispouredcontinuouslyfromafurnaceontoashallowbathofmoltentin.Itfloatsonthetin,spreadsoutandformsalevelsurface.Thicknessiscontrolledbythespeedatwhichsolidifyingglassribbonisdrawnofffromthebath.Afterannealing(controlledcooling)theglassemergesasa'fire'polishedproductwithvirtuallyparallelsurfaces.43Thetinbath44Formingthinnerribbons45Formingthickerribbons46AnnealingofglassAnnealing,inglassblowingandlampworking,istheprocessofheating,andthenslowlycoolingglasstorelieveinternalstresses消除玻璃制品在成形或热加工后残留在制品内的永久应力的过程称为退火。47AnnealingofGlassFlatglassmustbeannealedtofreeofstrainsothatitcanbecutstraightandeasily

平板玻璃必须通过退火来消除应力，以利直线切割Containersandpressedwaremustbefreeofstressessothattheydon’tspontaneousfailunderpressure

容器玻璃和受压器皿必须消除自身应力以避免在压力作用下突然破坏Opticalglassesmustbefreeofstressesthatchangetheindexofrefraction

光纤玻璃必须消除自身应力以避免折射率的变化Whyistherestressinglass?Temperaturegradientsacrossglasswallthicknessproducesdifferentcoolingrates

玻璃沿厚度方向温度的梯度将会引起冷却速度的不同Differentcoolingratesproducedifferenttimesatwhichtheglassundergoestheglasstransition

由于冷却速度的不同，不同部位发生转变的时间也不同Surfacescoolmorequickly,bulkcoolsmoreslowly

表面冷却更快，而内部冷却更慢48TemperatureMolarVolumeliquidglasssupercooledliquidcrystalfastslow49AnnealingofGlassAnnealingistoheattreatglassnearthesofteningpointtorelievestressesThentocoolmoreslowlybackthroughthetransitionregionsoastonotreintroducethermalstressesAnnealingtakestimeandtemperatureThickerglassannealsmoreslowly,haslargerstressesThinnerglassannealsmorequickly,hassmallerstressesGlasswithlargethermalexpansionrequiresmoreannealing50PreparationofspecialglassSol-gelmethod溶胶凝胶法Themethodisbasedonthephasetransformationofasol(asolutioncontainingparticlesinsuspension)ispolymerizedatlowtemperaturetoformawetgel,whichisgoingtobedensifiedthroughathermalannealingtogiveaninorganicproductlikeaglassoradrygel.51Preparationofspecialglass气相法该方法是以气体作原料，或者是将固体原料气化成气体，再加热发生化学反应而制备玻璃或非晶态物质的方法。该方法主要用于光纤预制棒的制造，也用于光掩模基板等的制造。52StructuralApproachtoGlassFormation53StructuralApproachtoGlassFormation1932 WilliamZachariasenpublishesthe“RandomNetworkHypothesis”ofglassstructureandhisrulesofglassformationinJ.Amer.Chem.SocietyStructuralApproachtoGlassFormationGlassFormationresultswhenLiquidsarecooledtobelowTM(TL)sufficientlyfasttoavoidcrystallizationNucleationofcrystallineseedsareavoidedGrowthofNucleiintocrystallites(crystals)isavoidedLiquidis“frustrated”byinternal“structurethathindersbothevents5455KineticapproachtoglassformationAllliquidscanbemadeintotheglassystateThequestionishowfastmusttheliquidbecooled?Fastquenching,>>100oC/sec,implies“strong”glassformingabilitySlowcooling,<<1oC/min,implies“marginal”glassformingabilityThecriticalcoolingrate,Rc,measureshowfastaliquidmustbecooled56Canliquidwaterbequenchedintoclass?57ThekineticapproachtoglassformationWhatistheRcvalueforaparticularliquid?IfRc>>100oC/sec,thentheliquidisapoorglassformerIfRcis<<1oC/min,thentheliquidisagoodglassformer58PropertiesofGlassTheglasstransitionTheglasstransitionistheregionoftemperatureswherethepropertiesofacooledliquidcontinuouslychangefrombeing“liquid-like”to“solid-like”StructureiscontinuouswiththeliquidstatePropertiesarecontinuouswiththeliquidstateYet,theGlassTransitionoccursoverarelativelynarrowrangeoftemperaturesandcanbea“sharp”transitioninsomecases59TheglasstransitionTheglasstransitionresultsfromtheslowingdownoftheinternalrelaxationtimenecessarytoachieveequilibriumpropertiesasthetemperatureisloweredRapidlyrisingviscosityandtheassociatedviscosityrelaxationtimeareatrootoftheslowingdownoftheliquids’responsetotemperaturechangeMostliquidshaveaweaklytemperaturedependentviscosityGlassformingliquidshaveastronglytemperaturedependentviscosityWhatistheviscosity?ElasticsolidsdeformelasticallywhenstressedTheyrelaxbacktotheiroriginalstatewhenstressisreleasedElasticmodulusistheproportionalityconstants=EeLiquidshavenorestoringforceTheyhavenoElasticmodulusItdoesrequireforcetomovetheliquidthoughRateofstrain,

Stress=viscositystrainrate60AreaAForce,FViscosity:Shearstressrequiredtoproducefixedstrainrate:Thehighertheviscosity

ThehighertherequiredstressVelocity61TemperaturedependenceofviscositySodalimeglassasacommonexampleViscositydecreasesrapidlyabovetheannealingpoint,TgDecreaseslessrapidlyathighertemperatures62Phaseseparation(分相):Nucleation(成核)andGrowthSpinodalposition(螺旋线分解)63Whyisphaseseparationsoimportant?Materialspropertieschangeandenon-uniformOpticalproperties,transparency,aredramaticallydegradedElectricalpropertiescanchangefrominsulatingtoconductingAppearancecanchangefromclearandcolorlesstodarkandabsorbingProcessingcanedifficultduetosecondhightemperatureliquidphasebeingcreatedGeneraloverallbehaviorofglasschanges64PropertiesofglassDensityThedensityofmostglassesisdependentuponitsthermalhistoryanddecreaseswithtemperatureGlassescooledatvariousratesfromabovetheannealingpointwilldifferindensitywiththemorerapidlycooledglasseshavingalowerdensityTemperatureMolarVolumeliquidglasssupercooledliquidcrystalfastslow65PropertiesofglassHardnessGlassesarebrittleinamacroscopicscale,buttheycanflowundershearstressesinamicroscopicscaleHardnessisapropertycloselyrelatedtothemechanicalstrengthofaglassandtoitslowtemperatureviscosity66PropertiesofglassStrengthThemeasuredmechanicalstrengthofglassismuchlowerthanthetheoreticalstrengthMostglassesshowareductionofstrengthwithincreasingtemperature67PropertiesofglassBrittlenessOneofthemaincausesofthislossofstrengthisthepresenceofsurfacedefectsThestresswillconcentrateoveronlyafewinter-atomicbondsattheapex(顶点)ofthecrackIftheglassiscooledtoorapidlyitdoesnothavetimetoreleasestressessetupwithinitduringcooling.Thesestressesare“frozen-in”andcancausetheglasstoshatter(粉碎)whenitesasolid.68PropertiesofglassOpticalPropertiesTherefractiveindexdependsuponthewavelengthoflight,thedensity,temperature,thermalhistory,stress,andcompositionoftheglassGlassesofhigherrefractiveindexhavegreaterdispersion.Thehighertheindex,themorethedispersiontendstoincreasewithdecreasingwavelengthTherefractiveindexofaglassanditschangewiththecompositionandheattreatmentareofprimaryimportanceforopticalglasses69PassiveVSActiveOpticalPropertiesofGlassPassiveTransmissionOpticsActiveTransmissionOpticsResponseistimeindependentResponseistimedependent70ColorofglassPropertiesofglassChemicalStabilityThechemicaldurabilityofsilicateglassesresultsfromtheinertnatureofsilicaitselfTwotypesofreactionmayoccurwhenaliquidattacksaglass:ionexchangeandnetworkbreakdownResistancetocorrosionDurable,i.e.extremelyresistanttocorrosion,andtheircompositioncanbechosentoenhancethisproperty.7172TheImportanceofChemicallyDurableGlassLargeamountsofarchitecturalglassareinplacearoundtheworldGlasssurfacequalitymustbemaintainedformanyyearsAirbornecontaminantssuchasNOx,SOx,producenitricandsulphuricacidsSuchacidsandsaltsdoattackglassandcausediscoloration73MechanismsofChemicalAttackofGlassLeachingof“mobileions”outoftheglassSi-O-Na++H+..OH->>Si-O-H++Na+OH-(aqueous)

+++++++74MechanismsofChemicalAttackofGl