Making GlassWord文档下载推荐.docx
《Making GlassWord文档下载推荐.docx》由会员分享,可在线阅读,更多相关《Making GlassWord文档下载推荐.docx(31页珍藏版)》请在冰豆网上搜索。
![Making GlassWord文档下载推荐.docx](https://file1.bdocx.com/fileroot1/2023-2/2/a1792a6d-d81f-4c20-b709-97b090251c36/a1792a6d-d81f-4c20-b709-97b090251c361.gif)
74
Na2O
14
CaO
11
Al2O3
1
FlatGlass
1.Relativelycheap.
2.Canbetoughened.
3.Weatherresistant.
4.Canbecoated.
Floatprocess.Castandrolled.
71
16
9
MgO
3
DomesticGlasswareforeverydayuseinhomeandcatering
1.Pleasantappearance.
2.Abilitytostanduptoconstantuse.
3.Doesnotaffectcontents
Mouthblown,pressedorfullyautomaticmassproduced.
K2O
5
B2O3
RadiationShielding
Highdensitytoabsorbradiation.
Extrusionandcastingcanbegroundandpolishedtoopticalprecision.
PbO
ThermometerTubing
Thermalstabilityoverawidetemperaturerange,retainingtransparency.
Automaticorhanddrawing.
Borosilicate
Leadglass
Dependingontemperature
rangerequired
LaboratoryGlassware
Highchemicaldurability.
Lowthermalexpansion.
Lampworking(madefromtubingbyheatingandskilfulmanipulation).
Mouthandautomaticblowing.
Sintering.
MainlyBorosilicateorfusedsilicaforextralowexpansioncoefficient
FullLeadCrystalDomesticGlassware
1.Extrasuitableforartistichandshapingandmouthblowing.
2.Brilliantfinish,attractivewhenfullorempty.
3.Comparativelysoft-easytocutandpolishorengrave.
Handmadebyskilledcraftsmen.
HeatResistantOventoTableWare
1.Resistanttothermalshock.
2.Attractive.
3.Easytoclean.
4.Canbeusedinmicrowaveovens.
Automaticallypressedorblown.
Borosilicateglass
80
4.5
12
OpticalGlass
1.Widerangeofrefractiveindices.
2.Widerangeofdispersioncoefficients.
3.Perfecthomogeneity.
4.Completetransparency.
Extrusionandpressing,thengroundandpolishing.
Whilerangeofcompositions
Dependsonapplication
ElectricalComponents:
cathode-raytubes,capacitorsandresistors,computercomponents,printedcircuits
Gooddielectricproperties.
Lowelectricallossesoverawiderangeoftemperatures.
Highoperatingtemperatures.
Blowing.
Drawing-inrodformandinsheets.
SinteringandPressing-glassisgroundtofinegrainsandthenissubsequentlypressedintorequiredshapeandthenfired.
Widerangeofcompositions
GlassBuildingBlocks
Resistanttonormaltemperaturechanges.Resistanttoatmosphericconditions.
Mechanicalstrength.
Attractive.
Translucent.
Automaticpressing
-pressedinhalvesandthenfusedtogether
Soda-limesilicaglass
Similartoflatglass
Ballotini:
minuteglassspheres(1-60microns)whichreflectlight
Highreflectiveproperties:
mixedwithpaintforroadsignsandcinemascreens.
flamedrawing
-velocityofflamesdrawsparticlesofglassuptowerandasthesoftenedglassfallsontheoutside,spheresareformedbysurfacetensioneffects.
GlassFibre
Highstrength-to-weightratio.
Resistanttoattackbycorrosivesubstances.
Resistanttohightemperature.
Flameresistant.
Highelectricalresistance.
Filamentdrawing.
Continuousfilament.
Whitewool.
Crownprocess.
Canbewovenintotextilesorincorporatedwithplasticstoforminsulatingmaterials,boathulls,carbodies,etc.
Sodalimesilicaandwhereresistancetoweatheringisnecessary,aborosilicateglassisused,e.g.
Soda-limesilicaglass
54.5
8.3
14.5
0.5
22.0
LightingGlassware
1.ElectricLightBulbs
Economicaltoproduce.
Easytomanufacturebymassproductionmethods.
Resistanttoshock.
Impermeableandinerttogas,vaporandliquid.
Durable.
Transparentortranslucent.
RibbonMachine
-producesbulbattherateofover1,000perminute.
Blanksusedinthemanufactureofvacuumflasksarealsoproducedbythismachine
Sodalimesilicaglass
72.5
1.3
6.5
3.0
15.9
0.3
2.SpecialGlasses
(a)Highpressuremercuryvaporlamps
Lowelectricalconductivity.
Resistancetointensechemicalactivityofmercuryvapor.
Specialglassescanbeformedbyusingmanufacturing
(b)Aircraftfire-warningsensors
Lowmeltingpoint.
processes,or,insomecases,laminatedontoordinaryglasses
(c)Glassforencapsulatingelectriccomponents
Highelectricityconductivity.
i.e.sodiumdischargelamps.
3.Tubingforfluorescentlighting
Resistancetointensechemicalactivity.
ElectricaldischargegeneratesUVlightwhichthencausesfluorescentpowdertoemitvisiblelight.
Highefficiency.
Longlife:
3,000-5,000hours,i.e.aboutoneyearofcontinuoususe.
AutomaticDrawing
2.6
5.7
2.9
14.6
1.2
4.Domesticandindustrialshadesandbulkheadlights:
inc.lensesfortrafficlights,carlightsandrailwaysignallights
Resistanttothermalshock.
Resistanttoweathering.Accurateandnonfadingcolor:
subjecttostrictBSspecifications.
Mouthblowing.
Handandautomaticpressing-dependingonquantitiesrequired.
1.Soda-limesilicaglass
2.Laminatedwithopalglass
3.Borosilicateglassesandopalglasses
WHATISGLASS?
Glassisaproductobtainedbythefusionofseveralinorganicsubstances,ofwhichnormallysilica(SiO2)intheformofsandisthemainone.Thefusedmassiscooledtoambienttemperatureataratefastenoughtopreventcrystallization,i.e.,themoleculescannotarrangethemselvesintoacrystallinepattern.Thefastrateofcoolingtopreventcrystallizationappliestotransparentglasses,whereasinthecaseoftranslucentoropalglasses,therateofcoolingissuchastoproduceapre-determinedlevelofCrystalformation.
TYPESOFGLASSES
Alargevarietyofglasswithdifferentchemicalandphysicalpropertiescanbemadebyasuitableadjustmenttochemicalcompositions.Furthersectionsofthisbookletdealwithvariousglasses,includingcrystalandopticalglassesofhighrefractiveindexandhighleadcontent.
CommercialGlasses
Themainconstituentofpracticallyallcommercialglassesissand.Sandbyitselfcanbefusedtoproduceglassbutthetemperatureatwhichthiscanbeachievedisabout1700oC.Addingotherchemicalstosandcanconsiderablyreducethetemperatureoffusion.Theadditionofsodiumcarbonate(Na2CO3),knownassodaash,inaquantitytoproduceafusedmixtureof75%silica(SiO2)and25%ofsodiumoxide(Na2O),willreducethetemperatureoffusiontoabout800oC.However,aglassofthiscompositioniswatersolubleandisknownaswaterglass.Inordertogivetheglassstability,otherchemicalslikecalciumoxide(CaO)andmagnesiumoxide(MgO)areneeded.TherawmaterialsusedforintroducingCaOandMgOaretheircarbonatesCaCO3(limestone)andMgCO3(dolomite),whichwhensubjectedtohightemperaturesgiveoffcarbondioxideleavingtheoxidesintheglass.
Mostcommercialglasseswhetherforcontainers,i.e.bottlesandjars,flatglassforwindowsorfordrinkingglasses,havesomewhatsimilarchemicalcompositionsof:
70%-74%
SiO2
(silica)
12%-16%
(sodiumoxide)
5%-11%
CaO
(calciumoxide)
1%-3%
MgO
(magnesiumoxide)
Al2O3
(aluminumoxide)
Withintheseverywidelimitsthecompositionisvariedtosuitaparticularproductsandproductionmethod.Therawmaterialsarecarefullyweighedandthoroughlymixed,asconsistencyofcompositionisofutmostimportance.Tothemixtureofchemicalsafurtherrawmaterialsadded-brokenglass,calledcullet.Culletcancomefromfactoryrejects,itcanbecollectedbythepublicinBottleBanksorfromthebottlingindustry.Almostanyproportionofculletcanbeaddedtothemix(knownasbatch),provideditisintherightcondition,andgreenglassmadefrombatchcontaining95%ofculletisbynomeansuncommon.AlthoughtheglasscollectedbyBottleBanksmaycomefromseveralmanufacturer,itcanbeusedbyoneofthem,ascontainerglasscompositionshavebeenharmonizedtomakethispossible.Itis,however,importantthatglasscolorsarenotmixedandthattheculletisfreefromimpurities,especiallymetalsandceramics.
Flatglassissimilarincompositiontocontainerglassexceptthatitcontainsahigherproportionofmagnesiumoxide.
Othertypesofglasses
Glassesvarywidelyintheirchemicalmake-up;
indeed,thereareveryfewelementintheperiodictablethathavenotbeenincorporatedinaglassofsomekind.However,mostoftheglassesproducedcommerciallyonalargescalemaybeclassifiedintothreemaingroups:
soda-lime,leadandborosilicate,ofwhichthefirstisbyfarthemostcommon.
Soda-limeglasses
Thesearethemostcommoncommercialglassesandhavebeendescribedinthepreviouschapter.Thechemicalandphysicalpropertiesofsoda-limeglassesmakethemsuitableforavisi