粉末喷涂与应用

粉末喷涂与应用第1页/共72页MetalPreparation金属的处理Pretreatmentisaprocessintendedtopreventthecorrosionofthepaintedmetal.前处理是一种提高耐腐蚀的工艺Fe2+O2+H2O = RUSTIronreactswithoxygenandwaterintheatmospherecreatingapowderybrownmess,notveryornamental,andcontinuousuntilnosolidmetalremains.铁在空气中会与氧气和水反应生成褐色的物质第2页/共72页MetalPreparation金属处理Severalmethodsofcorrosionpreventioncanbeused几种防腐蚀的方法ForSteel:铁：Automotiveapplications汽车业Primer:Underseals:LayersofPaint.

第3页/共72页Severalmethodsofcorrosionpreventioncanbeused几种防腐蚀的方法ForSteel:铁：ArchitecturalApplications建筑业Galvanising:AntiCorrosivePrimer*Galvanising–coveringwithalayerofzinc.MetalPreparation金属处理第4页/共72页MetalPreparation金属处理第5页/共72页MetalPreparation金属处理Severalmethodsofcorrosionpreventioncanbeused几种防腐蚀的方法ForAluminium:铝：Aluminiumoxidisestoformawhitecorrosionproduct铝被氧化后形成白色的物质ArchitecturalApplications

建筑业Anodise:AcidPrimers第6页/共72页MetalPreparation金属处理WhyPretreatment?为什么要前处理？Powdercoatingsareusedtoenhancetheappearanceofbuildings,machines,furniture,appliances:粉末涂料用于改善建筑，机械设备，家具，以及其它器具的表面：Designersandarchitectsaresearchingtogivedistinctionintermsofcolourandeffects.设计师和建筑师提供了包括颜色和效果在内的标准等级Theproblemisthatallpaintsareporous：所有的涂料均不同程度的存在会渗水的小孔第7页/共72页MetalPreparation金属处理Moleculesofwaterandsaltcanpenetratethroughthepaintfilm.Whentheyreachthemetalsurfacetheeffectisworsethanifthemetalisuncoated.Theanswer=Pretreatment水和盐分子可以渗透漆膜，一旦它们与金属表面接触，产生的影响甚至比没有喷涂还要糟糕。要解决这个问题就需要前处理。第8页/共72页MetalPreparation金属处理Pretreatment:前处理Thechemicalconversionofthemetalsurfacebeforeapplyingthepowdercoating.Themetalthenresistscorrosionandtheconversion

permanentlyimprovestheadhesionofthecoating.在使用粉末涂料以前用化学方法对金属表面进行处理，可以改善耐腐蚀性和增加涂层的附着力。第9页/共72页MetalPreparation金属处理Theperformanceofthepowdercoatingisonlygoingtobeasgoodasthemetalpreparation.Wewillcoverthreetypesofmetaltreatmentsystems粉末涂料的功能类似于金属处理，我们将介绍三种的金属处理方法IronPhosphateforSteel用于铁系的磷酸铁ZincPhosphateforSteel用于铁系的磷酸锌ChromateforAluminium用于铝的铬酸盐Othersystemscanbeusedandinformationisavailable.当然还有其它处理方法第10页/共72页MetalPreparation–IronPhosphate金属处理—磷酸铁Metalpretreatmentcanbeappliedbysprayordipping.金属前处理可以借助喷淋或浸渍Inthecaseofironphosphatetheprocesscouldlooklikethis:下面是磷酸铁的工艺流程Stages1,2and3canbeeithersprayordip步骤1，2和3均可采用喷淋或浸渍DRAINDRAINStage1Clean&PhosphateStage2RinseStage3Rinse&SealWorkFlow第11页/共72页MetalPreparation–IronPhosphate金属处理—磷酸铁Typical3StageSystem典型的3步骤流程MetalSubstrate Steel–PhosphatisingSystem金属基材

NoneFerrous–CleanandEtchStagetimeduration 1–90seconds不同步骤所需的时间 2–45seconds 3–30secondsStagetemperature

1，2和3步骤所需的温度 40–60oCDrying/干燥温度 100–120oCTypicalconcentration 2–3%byvolume典型的浓度

Typicalacidity典型的酸值

pH3.5–5.5Typicalcoatingweight 典型的膜重 20–40mg/ft.第12页/共72页MetalPreparation–ZincPhosphate金属处理–磷酸锌ZincPhosphateprocessforsteeltendstobemorecomplicated磷酸锌的工艺流程复杂一些Stage1CleanStage2RinseStage3Phos-phateStage4RinseStage5RinseDRAINDRAINDRAINDRAIN第13页/共72页MetalPreparation金属处理DwellTime:Eachstagedependson:各阶段所需的时间，受下面的因素控制

Theamountofpretreatmentchemicaldissolvedinwater溶于水的前处理化学药品的浓度

Theageofthechemical化学药品的有效时间Regularcheckingisrequiredtogiveconsistentgoodresults–atleasttwicepershift.通常要经常检查前处理的状态—一个班至少两次第14页/共72页MetalPreparation–ZincPhosphate金属处理–磷酸锌Typical5StageSystem典型5步骤流程MetalSubstrate Steel–PhosphatisingSystem金属基材

NoneFerrous–CleanandEtchStagetimeduration 1–90seconds不同步骤所需的时间 2–45seconds 3–60seconds 4–30seconds 5–30secondsStagetemperature温度 40–60oCDrying干燥温度 100–120oCTypicalconcentration典型浓度 2–4%byvolumeTypicalacidity 1=alkaline酸碱性 2=acidicTypicalcoatingweight

40–70mg/ft.典型的膜重第15页/共72页MetalPretreatment-BS3189Type3SprayPhosphatePlant9stagepretreatment九步法

Degrease脱脂

Rinse水洗

Rinse水洗

Rinse水洗AcidEtch(phosphoricacid)表调ZincPhosphate磷酸锌磷化

Rinse水洗

Rinse水洗

De-ionisedwater去离子水水洗

Dry干燥QualityStandard

BS6497参考英国标准BS6497第16页/共72页MetalPretreatment

–QualityControl金属前处理–质量控制TitrationChecks:检测项目：

1.Cleaner 2.Rinses 3.AcidConcentration 4.Rinse 5.PhosphateConcentrationandcoatingweight 7.Rinse 8.ObservationsCheckedatregularintervalsduringnormalproductionandbeforeproductioncommences以上项目应在生产过程中定时和生产前进行检验第17页/共72页MetalPretreatmentDry金属前处理干燥Toensuremetalsurfaceisdryreadyforpowdercoating.在喷涂粉末涂料前必须保证金属工件已经完全干燥Dryingoven-PhosphatePlant第18页/共72页MetalPreparation–Chromate金属处理—鉻酸盐Foraluminium–chromateconversion铝—铬酸盐处理BritishStandardsexistfortheconversionofaluminium–

BS6496适用于铝的英国标准BS6496ThesameconversioncanbeusedforGalvanisedsteel--BS6497适用于电镀铁的英国标准BS6497Stage1CleanStage2RinseStage3EtchStage4RinseStage5Chrom-ateStage6–7RinseStage8DeminRinseDRAINDRAINDRAINDRAINDRAINDRAIN第19页/共72页MetalPreparation–Chromate金属处理—鉻酸盐Typical7StageSystem七步法MetalSubstrate Aluminium/AluminiumAlloys金属基材

GalvanisedSteel–CleanandEtchStage1 CleaningStage2 RinseStage3 DeoxidisemetalsurfaceStage4 RinseStage5 ChromateStage6 RinseStage7 AcidulatedRinseStageTemperature 80–100oCDrying 90–95oCDonotoverheatatthedryoffstage干燥温度不能过高第20页/共72页MetalPreparation–Chromate金属处理—鉻酸盐ChromateconversiontoAluminiumandGalvanisedsteel鉻酸盐处理完铝和电镀铁后的变化YellowChromateConversion TypicalCoating黄色鉻酸盐的变化 Weight(g/m2)PaleYellow 0.2–0.7Gold 0.7–1.6Brown 1.6–3.5Greenmixchromate/phosphate 0.5–2.0

ForPowderCoatingalightweightcoatingisrecommendedIntherange0.2–2.0g/m2应用于粉末涂料，膜重一般在0.2—2.0g/m2第21页/共72页SprayingandApplicationofPowderCoatings粉末涂料的喷涂与应用第22页/共72页第23页/共72页第24页/共72页PowderApplicationSystems粉末涂料的应用系统第25页/共72页PowderApplicationSystems

FeedSystems粉末涂料应用系统供粉系统DirectfeedsystemfromDrumtoGun.粉末涂料直接从粉桶送至喷枪Thesystemshownfeeds1gun右图是只供一个喷枪的直接供粉系统第26页/共72页PowderApplicationSystems

FeedSystems粉末涂料应用系统供粉系统Directfeedsystemdirectlyfroma25kilobox.Thissystemissetuptofeed2guns.Usedmainlyinmanualoperations.右图为直接从粉末涂料的包装箱至喷枪的供粉系统。图中的设备适用于两把喷枪，通常用于人工喷涂。第27页/共72页PowderApplicationSystems

FeedSystems粉末涂料应用系统供粉系统Bulkfeedsystem,powderissuppliedinafibrebag.Weightofpowder–upto1,000kilosperbag.Usedmainlyonautomaticplantswherecolourchangeislimited.大型供粉系统，粉末涂料一般1吨一个包装，用于自动喷涂系统，限于换色较少的场合。第28页/共72页PowderFluidisationSystems粉末涂料流化系统Dryairpassesthroughamembranegivingthepowderliquidqualities.干燥的空气通过微孔板，使粉末涂料象水一样流动。Theairmustbedryandfreefromwaterandoil.空气必须除水和油第29页/共72页PowderDeliverySystems粉末涂料的传送系统第30页/共72页PowderDeliverySystems粉末涂料的传送系统ActualpowderfeedsystemVenturifeedfromfluidbed.右图是用文氏管从流化床吸取粉末的送粉系统第31页/共72页ForcesatworkonthePowderParticlesAtanyonetime4forcesareatworkonthepowderparticleasittravelsfromtheguntotheearthedwork-piece.粉末在离开喷枪到达工件时受4种力的影响AirResistanceElectrostatic AttractionWeight(Gravity)AerodynamicForce第32页/共72页PowderChargingSystemsThereare2majorcategoriesinchargingofpowdercoatingcoronaandtribo:粉末涂料主要有两种带电方法—静电/摩擦GunType ChargeLocation充电位置 Internal External Remote PowderSupply X XCorona静电法

IntegratedGun PowderSupply X XTribo 摩擦带电法

X第33页/共72页CoronaChargingSystems静电带电系统Inthismethod,ahighvoltagegeneratorisusedtochargeanelectrodeatthetipwhichcreatesanelectrostaticfield(orcorona)betweenthegunandthework-piece.利用高压电极使粉末带电，并在喷枪与工件间形成电场ExternalChargingSystem/外充电系统第34页/共72页CoronaChargingSystems静电带电系统Coronacharging -manualsystem/手动枪

-automaticsystem/自动枪第35页/共72页CoronaChargingSystems静电带电系统InternalChargingSystem内充电系统第36页/共72页CoronaNozzleSystems静电枪的喷嘴ThetypeofproducttoBecoatedwillinfluenceThenozzletobeusedontheSpraygun,twotypesareshown第37页/共72页CoronaNozzleSystems静电枪的喷嘴ConicalSprayNozzles–usedtogiveanevenlydistributedfilmthicknessoverflatpanels.圆锥型的喷嘴一般用于喷涂平面，并得到膜厚均匀的涂层。InterponAFparticlemanagedpowderbeingappliedondomesticappliances.右图为InterponAF粉末涂料用于家用设备第38页/共72页CoronaChargingSystems静电带电法Thehighvoltagepowersupplychargestheelectrode高压发生器使喷枪电极带电Theconcentratedchargecreatesanelectrostaticfield带上电荷后形成静电场Theelectrostaticfieldcausestheairtoionizeandgenerateacorona静电场使空气电离形成电晕Thecoronaemitselectrons电晕放射出电子Theelectronsarepickedupbyoxygenmoleculesformingnegativeions这些电子借助氧分子形成负离子第39页/共72页CoronaChargingSystems–cont.静电带电法Theionsfollowthefieldlines负离子沿着电力线移动Thepowderparticlesdistortthefieldaroundthem粉末涂料粒子使周围的电力线产生扭曲Thedistortedfieldlinesdirectionstothepowderparticles扭曲后的电力线引导离子被粉末涂料粒子吸附

Theionsbombardthepowderparticlesandtransfertheelectronsgivingtheparticlesanegativecharge吸附的离子轰击粉末粒子，并使其带上负电，形成负极第40页/共72页TriboChargingSystems摩擦带电法Triboelectricityisgeneratedbythefrictionofonematerialonanother.InTribochargedsprayguns,thepowderrubsonaspeciallyformulatedandshapedsurfacewhichallowschargetotransfer.摩擦带电是通过不同物质摩擦形成的，摩擦枪可以使粉末与特殊设计并有特殊结构的表面摩擦而带电第41页/共72页TriboChargingSystems摩擦带电法第42页/共72页TriboChargingSystems摩擦带电法Tribonozzlesindifferentconfigurations.不同结构的摩擦枪喷嘴第43页/共72页ElectrostaticFluidBedSystems静电流化床法第44页/共72页PowderPenetration粉末的吸附Thepictureshowsthedevelopmentofthecorona(reddottedarea).Articlespassingthrougharechargedwiththenegativeions(-).Thechargedpowderparticlesareattractedtotheearthedsubstrate.右图显示了电场，电力线，粉末的充电及被接地的工件吸附过程。第45页/共72页PowderPenetration粉末的穿透Achievingpenetrationintodeeprecessesinmostimportantwhenapplyingpowdercoating.粉末涂料能否到达死角这对粉末涂料的应用来说很重要ThemosteffectivecontrolsarethenozzlepatternAndairassistance.有效的控制方法是选择合适外形的喷嘴及调整辅助空气Itispossibletoovercomethe“FaradayCageEffect”现在，克服“法拉第”效应已成为一种可能第46页/共72页PowderPenetration粉末的穿透Reducingthe“FaradayCage”Effect减弱“法拉第”效应ToreducetheeffectitisnecessaryToassistinthecreationofchargedairParticlesinsidetherecess.Thisshouldbe彻achievedbyincreasingtheairstream.可以借助加大传送空气的压力来减弱“法拉第”效应第47页/共72页FaradayCageEffect“法拉第”效应

AFaradaycagecantechnicallybedefinedasanareawithinwhichthereisnoelectrostaticfield. Infinishing,thistermisappliedmoreloosely,andgenerallyreferstoanareasuchasinsidecornersorcavitiesthataredifficulttocoat. Thereasonwhytheseareasaredifficulttocoatisthattheadjacentsurfacestotheinsideofthecornerattracttheelectrostaticfiled,thereforedeflectingthepowderfrompenetratingintotherecessedareas. Atthesametime,thisrecessedareaisdifficultfortheaerodynamicforcestopenetrateintowithoutblowingpowderoffalreadycoatedareas.

法拉第区域可以被认为是静电屏蔽区。实际应用中定义更宽松，通常是指死角和洞等难喷涂区域。难喷涂的原因是这些区域的外围吸引了电荷，这样粉末就不能被吸附。另外，从空气动力学来将，输送空气将粉末吹至这些区域也很难。第48页/共72页BackIonisation反弹效应A=powderattractedtotheearthedcomponentB=builduptocorrectfilmthicknessC=ionisedairwithinthepowderfilmrepelsoncomingparticles

A=粉末吸附在接地工件B=形成合适的膜厚C=在涂层上的离子云抵制吸附带有同类电荷的粉末第49页/共72页PowderRecoveryIntegratedSystem粉末回收系统IntegratedSpray/RecoveryBoothSystem完整的喷涂/回收系统第50页/共72页PowderRecoverySystems粉末回收系统Typicalcartridgeback-Pulsecleaningdesign.UsedincartridgeRecoverysystems.典型脉冲自清理设计，通常适用于桶状回收系统第51页/共72页PowderRecoverySystems粉末回收系统CycloneRecoverySystemThecycloneisusedtoseparatethepowderparticlesfromtheair.Theairisdrivenroundthesidesofthecyclone,reducinginvelocityandreleasingthepowdertobecollectedatthebase.Finepowderisusuallytransportedoutofthecycloneontheairflow.旋风分离器根据粒径分离粉末，空气沿着旋风分离器壁做圆周运动，速度渐渐降低，并释放被收集的粉末至底部。细粉通常会随流动空气离开旋风分离器。第52页/共72页PowderRecoverySystems粉末回收系统Finepowderiscollectedonafiltersysteminthe“afterfilters”.Thepneumaticairpulseensuresairflowisconsistentandthefinepowdercollectedfordisposal.细粉通过滤芯滤层被收集。有力的气体脉冲保证了空气流动的连续性及需被分离的细粉收集。

第53页/共72页PowderRecoverySystems粉末回收系统Amotorgeneratestheairflow.Ensuringthecorrectairvolumeandvelocityismaintained.电机提供流动空气，并保证气体流量和速度。第54页/共72页Powderin-lineSievingSystems粉末过筛系统RotaryIn-LineSieve旋转筛第55页/共72页PowderVibratingSievingSystems震动筛Vibratingsievesaredesignedtoworkeither: -Freestanding -In-line震动筛适用于： -独立区域 -流水线第56页/共72页PowderReciprocatorCycle粉末喷涂的往复机构CycleRate往复速度=No.OfGunsxPitchofGunsx60喷枪数量x喷枪位置x60ConveyorSpeed(mm/min)传送链速度（毫米/分钟）Thiswillensurestriationsdonotoccuronthecomponentsbeingcoated.在喷涂中要保证不要形成带状涂层。第57页/共72页ApplicationPractical实际应用第58页/共72页StovingandCuringofPowderCoatings固化炉及粉末涂料的固化第59页/共72页TypesofOven固化炉的类型Convection–energyistransmittedbyaircirculationtoheatthecomponents对流–热量通过空气流动传送，加热工件Radiation–energyistransmitteddirectlyontothepartswithoutheatingairbetweenthepartsandtheradiationsource辐射–热量直接从辐射源被传送至工件而无需空气作媒体Induction–energyistransmittedthroughinducingelectricaleddycurrentsthatgenerateheatinthemetalparts感应–热量借助电流来传送来加热金属工件第60页/共72页TheBakingProcess固化过程Thebakingstage,duringwhichthepowdercoatingmelts,flows,gelsandfinallychemicallyreacts(cross-linking)andcures.Itiscriticaltotheperformanceofthecoatingthatthetemperatureandtimeattemperaturearemaintained.Mostbakingovensaredesignedtotakethesubstratethroughapre-programmedtime–temperatureprofile.固化过程包括粉末的熔融，流平，凝胶最后发生化学反应形成涂层。固化温度极其所占时间是非常重要的，大多数固化炉借助预先设置固化时间（温度曲线）来设计。第61页/共72页PowderApplicationRadiationStoving粉末的辐射固化GasfiresInfra-Redovenusedforindustrialcomponents.左图为用于固化工业用品的瓦斯红外炉I-Remittersinsidetheovencurethepowderfilmwhenindirectline,asradiationenergy.右图为通过炉内红外发生器（热源）固化粉末涂料I-Risoftenusedtoboostthecuringinfrontofaconventionalaircir