優(yōu)化大氣等離子噴涂工藝設(shè)計(jì),降低TBC熱障涂層生產(chǎn)成本

./TBCcoatingcostreductionbyoptimizatonoftheAtmosphericPlasmaSprayprocess優(yōu)化大氣等離子噴涂工藝,降低TBC〔熱障涂層生產(chǎn)成本S.Mihm,T.Duda,Birr/CH,G.Thomas,H.Grner,?gewil/CHandB.Dzr,Ilmenau/DThegloaleconomcgrowhhastrigrdadraaticncreseintedemadforresurcsoerthelastfwyears,resultinginseadyprceicrasesfrnergyadrwmaterals.Inthegastrbinemaufacturingsectr,processoptimizatinsofcost-intnsivepodctionstesivolveaheihtenedsavigspotntialandformthebassforscurngfuturecometitiveadvanagsnthemarketecnomy.全球經(jīng)濟(jì)增長(zhǎng)在過(guò)去的幾年中引發(fā)了對(duì)資源需求急劇增加,導(dǎo)致能源和原材料價(jià)格穩(wěn)步上漲。在燃?xì)廨啓C(jī)制造業(yè),對(duì)成本密集的生產(chǎn)工藝優(yōu)化具有成本節(jié)約的潛力并能為企業(yè)在將來(lái)市場(chǎng)經(jīng)濟(jì)的競(jìng)爭(zhēng)中打下堅(jiān)實(shí)的基礎(chǔ)。Inthiscontext,theatmosphericplasmasraying<APS>processforthermalbarriercoatings<TBC>hasbeenoptimized.AconstraintfortheAPScoatingprocessoptimizatonistheueoftheexistingcoatingequipent.在這樣的大背景下,熱障涂層〔TBC的大氣等離子噴涂〔APS工藝得以改進(jìn)優(yōu)化。而APS制備涂層工藝優(yōu)化的一個(gè)限制條件在于現(xiàn)有涂層設(shè)備的使用。Furthrmre,thecrrentcoatigqalityandchrctersicsrenotallwedtochngeinordertooidnwqualificationndtesting.此外,為了避免重新申請(qǐng)資質(zhì)以及進(jìn)行額外測(cè)試,還不能改變當(dāng)前的涂層質(zhì)量和性能。Usngexerenceinatoshercplmasprayingandepricallygaindata,theressptimizaionplnincldedthevariationofe.g.theplasmagascmpstionandflowrate,theelectricalpwr,thearraneentandangleoftheowerinectrstotheplmajet,thegrainszedstrbutionofthespraypwdrandthepasmatorchmovementocdurelkespraydstace,offsetaditeration.Inarticuar,pasmaproprtis<enthapy,velocity,temperatur>,powdrinjctioncoditins<injctionpoint,injctinspeed,granszedisriution,>swllastecoatiglamiation<coatigpattern,spryingdistac>areexamied.Theptimizedprcsadrsultigcatigwscoprdtothecurntsituationyseveraldignsticsmethos.在以往大氣等離子噴涂經(jīng)驗(yàn)和日常獲取的寶貴數(shù)據(jù)基礎(chǔ)上,我們的工藝優(yōu)化計(jì)劃包括一系列的改變,如等離子氣體組成,流量；用電,布局及粉末注入等離子流的角度,粉末的粒徑分布、等離子槍的移動(dòng)〔如噴距、偏差以及重復(fù)性等。特別是等離子性能〔焓值、速度以及溫度,注粉條件〔注粉點(diǎn)、注粉速度、粒徑分布,以及還有涂層〔涂層形式,噴涂距離等方面做了重點(diǎn)研究。我們將優(yōu)化后的工藝及其所制備的涂層與當(dāng)前普遍使用的幾種工藝采用不同的分析方法進(jìn)行了對(duì)比。Theimrovdprcsprovidessignifcantlylowercstsbycievingtherquirmentofcomarblecoatingquality.Furtermre,acntributionwsmaetoabettercomrehesinoftheatmspricpasasrayingofceramcsndamethodforfutureprcsdevelpmntswsdefied.在同等涂層質(zhì)量的前提下,優(yōu)化后的工藝能很大程度的降低生產(chǎn)成本。此外,我們對(duì)大氣等離子陶瓷粉末噴涂過(guò)程做了一些詳細(xì)描述,使其更加通俗易懂,同時(shí),我們還了未來(lái)工藝的研發(fā)方法。1Introdution引言Plasmacoaedthrmalbarrieroatngs<TC>resccessfullyestablsdinthegasturinemanufcturgbsiesssncethesevnties[1].IntehotgassectionofgasturbinesBC`sfulfillhefunctiosofheralisultion,therefelowerigtetemperatureofthemetallcprtionoftheprt.Firigtemperatursintecmbustincambrboe130°Cndimitedlongtrmopratintemperatursofapprox.950°Cfortheetallicateralsresultingnhighreuirmentstocatingsystesnbads,vanesndcmbustrprts.從上世紀(jì)七十年代起,采用等離子技術(shù)制備的熱障涂層〔TBC成功應(yīng)用到燃?xì)廨啓C(jī)制造業(yè)。在燃?xì)廨啓C(jī)的熱燃?xì)忸I(lǐng)域,熱障涂層滿足了隔熱的要求,從而降低了工件金屬部分的溫度。燃燒室的燒結(jié)溫度超過(guò)1300攝氏度,而大部分金屬材料的長(zhǎng)期工作溫度在950攝氏度左右,這樣一來(lái),就勢(shì)必導(dǎo)致旋片,小葉片以及燃燒室部件在噴涂時(shí)的高要求。Typicalthmalbrrircoatigsareulti-lyersystesasdonadplexsrcture,aensemetallcbondcoatlyer<matrial:MCrAlY,M-Niand/rC>andaproscramctpcoatlayer<materal:YSZ,yttrium-stabilizedzircona>,showninFig.1.典型的熱障涂層是一個(gè)以復(fù)式結(jié)構(gòu)為基礎(chǔ)的多層系統(tǒng),包括致密金屬結(jié)合涂層〔材料如：MCrAlY,M-Ni和/或C,以及上層多孔陶瓷涂層〔材料如：YSZ,釔穩(wěn)定氧化鋯,如圖1所示。Fig.1.plasacoatdTBC-catingsstemonturbneblade圖1：輪機(jī)葉片上的熱障涂層系統(tǒng)〔等離子制備TheeseCrAlYcoatigprotecstebseaterialagaistcorroson/oxidatonadprovidsteconctionorthecermictopcot.Theprusceramictopcoatfunctionsinconnectionwiththeexternalndinternalcoonentcooligasathrmalbarrier.ConrarytothedeseCrlYcoatingadefinedorsityoftheYSZcoatingsncssarytocomesatestraindiffernceandtoredcethralcodc.Thsepccrquientspsechalengetothetechlogyforprducngsuchcoatigsstms.CrAlY致密涂層對(duì)母材起到了抗氧化防腐蝕作用,并同時(shí)實(shí)現(xiàn)了與表面陶瓷涂層的連接。表面多孔陶瓷涂層一來(lái)用于與里面的涂層相連,也為其所覆蓋的內(nèi)部部件形成了一個(gè)熱障礙層,起到了冷卻的作用。相對(duì)于CrAlY致密涂層而言,固定孔隙率的YSZ涂層對(duì)拉力差異補(bǔ)償及降低導(dǎo)熱率來(lái)說(shuō)是非常必要的。而這些特殊要求就對(duì)當(dāng)今涂層生產(chǎn)技術(shù)提出了新的挑戰(zhàn)。Inadditintonsurecoatingquality,hemanufcturgcstsremorendoreinfcsofcurrntdeveopmens.除涂層質(zhì)量外,制造成本也越來(lái)越成為了當(dāng)前發(fā)展的焦點(diǎn)問(wèn)題。TheprodctonofporosYSZcoatigsisdonebyAtmoshericplasmasraying<APS>.Usingthistechologyheplsatorchcostructionsoelimitingfactorforprocessmproveents.Forexapevoltageadpowerflctutionsinfleethearticeproertisegatively[2],[3],[4].Theuseofcylindrcalnozzedesignlimitsthepossibilityofadjstingteplsmaflow.Byseveralnwpasatorchcocts<multi-eecrode,casce,highpowr[5],[6],[7],[8]>newcharacteristcsarechievdwhichcancntribuetoardctioninmaufacturngcst.Thetraditioalsigl-cathod-aodeplasatorchbasednF4MC60istemostwidely-sedsystmforyears.spcallyinturbnemanufcturgthissystemissedforcoatigcompoentswithcompexgeomerisndaccrdngtothistaretedprodctextensivemnipulationsquecsofteplsmatrchisrequired.多孔YSZ涂層通過(guò)大氣等離子工藝〔APS進(jìn)行噴涂。而采用該項(xiàng)技術(shù)進(jìn)行工藝改造的關(guān)鍵限制因素是等離子槍的設(shè)計(jì)制造。如電壓和電流的波動(dòng)會(huì)影響到粉末顆粒的性能[2],[3],[4]。圓柱形噴嘴的使用限制了等離子流調(diào)整的可能性。通過(guò)采用一些新的設(shè)計(jì)理念〔如多電極、串聯(lián)方式,大功率等[5],[6],[7],[8],等離子噴槍開(kāi)發(fā)了一些新的性能,從而能達(dá)到降低生產(chǎn)成本的目的?；贔4/MC60基礎(chǔ)上制造的傳統(tǒng)單陰陽(yáng)極等離子噴槍系統(tǒng)已經(jīng)廣泛推廣并使用多年。特別是在輪機(jī)制造行業(yè),該系統(tǒng)用于復(fù)雜工件的噴涂,因?yàn)楣ぜY(jié)構(gòu)復(fù)雜,等離子噴槍的安裝工序就更繁雜一些。ForthecatingprocessfturbinecmponntswithporusYSZcoatingandaporsityclssof>15%,themanufcturgcstsecludngwerparsforadeprecatedequipentlkeF4withpicalcatigparmetersreshwninFig.2.輪機(jī)部件的YSZ多孔涂層噴涂工藝〔孔隙率大于15%的成本計(jì)算在圖12中做了圖示說(shuō)明,采用典型參數(shù)進(jìn)行噴涂,費(fèi)用中不包含部件磨損和F4這樣的設(shè)備折舊費(fèi)用。Fig.2.cstallocationofAPSprocessorporousYZcoatig,excludingwerpartsad deprciatdequipent圖2：采用APS工藝制備多孔YSZ涂層的成本計(jì)算圖,部件磨損及設(shè)備折舊費(fèi)用不在計(jì)算范圍內(nèi)Plasmaparameterswithatotalgasflowrate<30slpmandnrgn/hydrgenratioof4:1,aswellasaelectrcalpwerof<30kWrsultbyapowdrfeedrateof80g/minindpositinefficiency<ratioofdepsitedpwdrweighttofeededpwdrweight=DE>ofabot35%.Inrelationtocurrentcstsofemployee,eectrcity,gasesandpwder,theYSZpowderseisthemajrcstfactorofthecoatigprcss.Thencraenprcssecencybyustheexistingequipentwithnocageofcatigquality<orosity,porsitydistrbtion,coatigthicknss,sress,thermashkstabiliy>isbenefcalbecasenoadditioalinvestmentcossoccrandahighdereofexperieceinhandlingheequimetisretaind.Aparalleluseofalradyalifiedcoatigprcsseswththeexistigequimentispssbleswell.Inthiscontextanmproveentoftheplasatorchquientbasednasinglcathod-aoesstemwithsusqentcoatigparameeroptimizatinisone.Targetistoralizeamoreefficientprcsswithncresedeffectivecatigdeposition.等離子參數(shù)為：燃?xì)饪偭髁?lt;30slpm,氧氣/氫氣比率為4:1,功率小于30kW,這是因?yàn)?5%左右的沉積效率〔粉末沉積重量除以送粉重量的比率=DE,送粉率的送粉速度為80g/min。按照目前的人工、用電、燃?xì)夂头勰┏杀?YSZ粉末無(wú)疑是噴涂過(guò)程中的主要成本因素。通過(guò)使用現(xiàn)有噴涂設(shè)備,涂層質(zhì)量保持不變〔孔隙率、孔隙率分布、涂層厚度、應(yīng)力、熱震穩(wěn)定性的前提下,提高噴涂效率是非常有益的,因?yàn)椴](méi)有產(chǎn)生額外的成本,并且工人以往積累的設(shè)備操作經(jīng)驗(yàn)也得以保留。更難能可貴的是,它并不影響在現(xiàn)有設(shè)備上使用以往的噴涂工藝。在這樣的背景下,在單陰陽(yáng)極系統(tǒng)上進(jìn)行的噴槍改造以及噴涂參數(shù)優(yōu)化工作得以進(jìn)行。優(yōu)化目標(biāo)是通過(guò)增加涂層有效沉積率,從而達(dá)到提高生產(chǎn)效率的目的。ExperimentlWork試驗(yàn)工作2.1Motiation試驗(yàn)動(dòng)機(jī)Thecrrntcatingocssasdontecomerciallywidelysreadsinge-cathod-aoesystem,suchasF4/C0.Assmingthtaslow,hghenthalpyplmajetisncessarytorduceaprosYSZcoating,theusdeuipment<plsmatorch>withacylindrcalozzledsign<diaeter8m>andatotlgasflwraelesstan30spmsnotoptimal.Arealzedeositionefficncyof35%leastohihpowdercoumption,increasedcoatigtimesandresultsinighcsts.Furthrmre,duetotheasymmericlasmajet,thepwdrinectionhstobeadaptdeveryprodctionsetupnddjustdtotheplasajet.nitialsetuptstslkespraysotaalyssandcatingoftestpartsforprcscontrolligareneedesslycomplicatedndcasehghworkodbeforerdctionstrtadleadtoaddtionalcsts.當(dāng)前使用的涂層工藝是在商業(yè)上廣泛推廣的單陰陽(yáng)極系統(tǒng),如F4/MC60。假設(shè)制備多孔YSZ涂層時(shí),需要慢速高焓值的等離子射流,那么以往總量小于30slpm的燃?xì)饬髁恳约皥A柱形噴嘴設(shè)計(jì)〔直徑為8mm的設(shè)備〔等離子噴槍就不是很理想了。如果要達(dá)到35%的沉積效率,就意味著粉末用量增加,噴涂時(shí)間延長(zhǎng),并最終導(dǎo)致噴涂成本升高。此外,由于等離子流不對(duì)稱,注粉時(shí)不得不調(diào)整工裝以及粉末注入等離子流的角度。在正式生產(chǎn)前進(jìn)行的初始工裝測(cè)試,如噴涂點(diǎn)分析,對(duì)測(cè)試部件噴涂所做的工藝控制都造成了不必要的復(fù)雜以及高強(qiáng)度工作,從未最終導(dǎo)致了成本上升,費(fèi)用增加。Inordrtosimplifythesetuprceurendtoachevetimesavins,asablendcosistntplsajetisneeed.Cosquentl,twomaintargetsforptimizationofthecoatigprcsscanedeined.1.Improveofepsitioneffciecyofthecoatigprcss<torducethemaufacturngcsts>2.Genrateastablendcnsstentpasmajet<impctonidirctadddvalue>Oneopprtnitytoinflunceprocessstabilityadplasaproertiesstheadjustentoftheandedesgnwhhisfnctiningsanozzle.ormerinvestigatinswithdifferntnozzledsigsshwapotentialtocrasetheefficiecyofteatmspercplasasraing[9].Basednthesefindigsanewnzzedesinwsdeveloed,whichisdapedtothereuiredoudrycoditiosfrcatingprocessofturbecomonens<minimumspraydistance>.Thisnewnozzleconfiuratin<VMT-nozze>tebassfortefollowigpressoptimization.為了簡(jiǎn)化工裝并節(jié)省時(shí)間,等離子射流必須要穩(wěn)定并連續(xù)。這樣一來(lái),涂層工藝優(yōu)化的兩大目標(biāo)由此可以得到確定：提高涂層工藝的沉積效率〔降低生產(chǎn)成本制造連續(xù)穩(wěn)定的等離子射流〔影響間接附加值影響生產(chǎn)穩(wěn)定性以及等離子性能的其中一個(gè)方式是調(diào)整對(duì)陽(yáng)極的設(shè)計(jì)〔陽(yáng)極作為噴嘴使用。以往改變噴嘴設(shè)計(jì)的研究表明了通過(guò)此方法提高大氣等離子噴涂效率的可能性[9]。在此基礎(chǔ)上,我們?cè)O(shè)計(jì)了一個(gè)新型噴嘴,該新型噴嘴能很好的適應(yīng)葉片部件的邊界噴涂〔最小噴距。而該噴嘴的配置〔VMT-噴嘴是接下來(lái)工藝優(yōu)化的前提和基礎(chǔ)。2.2 Optimiztionapproah優(yōu)化過(guò)程Previosstdiessowaconflctbetweenicresigthedeositinefficiecyndthenedofacosistntcoatigporsity[10].Byincresingtenumbraddesityofmoltenpartcleinthesprystream,thecoatigensityincrasesandthereuiredprsitydecress.The maininfluecingfactorrecosquntlytemperature,velocityanddistriutionofparticesintespraystrem.TorealzeanncresdDEapssibeaprochsaholsticaminationofthecoatigprocs,descrbedinFig.3.之前的研究總是會(huì)在提高沉積效率和保持一致的涂層孔隙率之間相互矛盾[10]。通過(guò)在等離子射流中增加熔融顆粒的數(shù)量和濃度,可以達(dá)到涂層密度和孔隙率降低的目的。而主要的影響因素是等離子射流中粉末顆粒的溫度,速度以及粒徑分布。為了提高沉積效率,一個(gè)可行的辦法是按照?qǐng)D3的程序?qū)φ麄€(gè)噴涂工藝進(jìn)行全面的檢查。Fig.3.plasmacoatigprocess,singasinge-cathode-anodesstem<e.g.F4/MC60>圖3：采用單陰陽(yáng)極系統(tǒng)〔如F4/MC60進(jìn)行的等離子噴涂示意圖,Potentialinflencngvrialesofthecatingrcssoptimizatinsare<elcted>:等離子噴涂工藝優(yōu)化的潛在影響因素〔選定的a>Adjutmentofplasmapopertis:Plasmaenthalpy,-velocity,-viscsity,-density,-temperatureodifiedby→plsagases,→elctrcalowr,voltag,voltagefluctuatiosa>等離子性能的調(diào)整：下列因素可以改變等離子焓值、速度、粘度、濃度、溫度：→等離子氣體→電流、電壓、電壓波動(dòng)b>Adjutmentofpaticlepopertis:Particlerainsizedistrbuton,particevelocty,temperauremdifiedby→powderfeedrate→carrirgsflow→injctioncnditiosb>粉末顆粒性能的調(diào)整:下列因素可以改變粉末顆粒的粒徑分布、速度以及溫度：→送粉率→載氣流量→注粉情況c>Adjutmentofcotingeposition:Coatigthickness,-prsiy,-porosityistributinmodifiedby→spraydistance→moveentprceure→robotvelcity,offset,numberoflayersc>涂層沉積的調(diào)整：下列因素可以改變涂層厚度、孔隙率以及孔隙分布情況：→噴距→行走程序→機(jī)器人速度、偏差以及噴涂遍數(shù)1.3 Experimentlprocedure試驗(yàn)程序Thefirststepoftheptimzationprocessfcssonincresingtedpsitionefficiecy.Teaalyssecarridoutycoatingstaicspraysots.Thescdstepinvolvsanadaptinofthecoatngproprties<prsity/porsitydistrbution>andisrealizedycoatigsrins.Astrngsacatingwhchsroucdbyaverticalmovementoftherobot<cnstntrootsped>withohorzontaloffsetandterefrewithnooverlapingfpaths.工藝優(yōu)化的第一步就是提高沉積效率。研究分析是在固定噴涂點(diǎn)上進(jìn)行的。第二步則是改變涂層性能〔孔隙率/孔隙率分布并通過(guò)涂層列來(lái)實(shí)現(xiàn)。涂層列是指通過(guò)機(jī)器人〔機(jī)器人速度恒定垂直運(yùn)動(dòng)來(lái)進(jìn)行噴涂所制備的涂層,無(wú)水平偏差,因此不會(huì)產(chǎn)生涂層重疊的情況。Testeris>Adjustmntofplasmapopertis:testobjcts=spraysposDevelopmenttarget=icrasigofDEtomaximum試驗(yàn)A系列>等離子性能的調(diào)整試驗(yàn)對(duì)象=噴涂點(diǎn)試驗(yàn)?zāi)康?將沉積率提高到最大值Byatheoretcalsumptonthatthearticleveociyshuldeslwspssibletogenrateahighporoscoatig,itisncssaryordcetetotalgsflwratetoaminmum.Frthrmoreahighempratureoftheplasajetisfavourdtoraisetepercentgeofmoltenprticlesadthrughthisanincresingofdepsitionfficiency.Tisfactsnfluecedychngigthecntentofmoleculrgs<hydrogn>intheplasa.ThetestsrestooptimizeDEarednebycnstntcatingdstace,costanteecrcalpower,cnsantpowderfedrate.從理論上假定,如果需要制備多孔涂層,則粉末速度需要越慢越好,如降低粉末速度,則總?cè)細(xì)饬髁勘仨氁抵磷畹汀Ａ硗?等離子射流的溫度越高,粉末熔融的比率就會(huì)越高,這樣一來(lái),沉積率也相應(yīng)得到提高。但改變等離子流中分子氣體〔氫氣含量可以影響該情況。通過(guò)恒定噴涂距離、恒定電流以及恒定送粉率來(lái)實(shí)現(xiàn)沉積率優(yōu)化系列的實(shí)驗(yàn)。Theowderfeedrateofthestndrdcoatingrcsswith80gminhsensed.oachieveheminimumcatingdistncetheplasaprpertis-velocity,temperatreareinfluecedyvaryingtotalgasflwraeandrg/hydrognrtio.ResulsofthesetstsriesaresowninFig.4.標(biāo)準(zhǔn)噴涂工藝使用80g/min的送粉率。為了達(dá)到最小的噴涂距離,通過(guò)改變氣體總流量以及氬氣和氫氣的比率來(lái)調(diào)節(jié)等離子性能〔速度和溫度。該系列試驗(yàn)的結(jié)果如圖4所示：Fig.4.influeceofargonhydroenratoandtotalgsflowtoDE,P=30kW圖4:氬氣/氫氣比率及總氣流對(duì)沉積率的影響,P=30kWIncosieraionofaodeandcathewarndalimitation oftheusedequipent, aratioofargn/hydroenof4:1ndatotalgsfowrateof7.5slpmrechse.TheometryoftheVMTnozzleleastoareuctionoflnthoftheemittedpasajetcomaredtothecylinriclnozzle,Fig.5.Durngteprevioststsitbcomsceartattheprstinjectincoditionof100°inplasmaflowdirectinisnottheoptimumfortheVMTnozzle.考慮到陽(yáng)極和陰極的磨損以及所使用設(shè)備的限制,選擇4:1的氬氣/氫氣比率,氣體總流量為37.5slpm。如圖5所示,相對(duì)于圓柱形噴嘴,我們?cè)O(shè)計(jì)的幾何形狀的VMT噴嘴減小了等離子流發(fā)散的長(zhǎng)度。按照之前的試驗(yàn)結(jié)果,目前的100度并不是VMT噴嘴的最佳注入角度。Fig.5.Imaesofplsajetsstanard<top>.optimizd<tton>圖5：標(biāo)準(zhǔn)等離子流〔上圖與優(yōu)化后的等離子對(duì)比效果圖〔下圖Duetothstepwdrinjctionointisplacedclosertothenozzleexit,theinjectionngleschngedrm100°to0°nflowdirecton.Theresltisalogerexposuretimeofprticlsinthepasajetrsultingnanehacedmeltingbaviour,theDEincrassfrom28%to46%.由于這樣的原因,注粉點(diǎn)設(shè)置得離噴嘴出口更近,而注粉角度就從順流方向100度變?yōu)?0度。這樣一來(lái),等離子流中粉末顆粒的暴露時(shí)間就會(huì)延長(zhǎng),那么粉末熔融情況得以加強(qiáng),沉積效率從28%增加到46%。FortheseectedplsaparametrandowerinjectincoditiontheDEisoptimzedrelatedtoteadjstmentofelectrcalpwer,Fig.6.在選定等離子參數(shù)及注粉條件的情況下,如圖6所示,通過(guò)調(diào)整電流達(dá)到提高沉積效率的目的。Fig.6.influnceofelctrcalowervriatiosonDEandarcvoltge,powderA圖6：電源調(diào)整對(duì)沉積率以及電弧電壓的影響示意圖,粉末AForthenvstigatedeltricalowerranethearcvoltageisamostcostntTheassciatedcostntarclength indicates afixation oftheaneattacheent<arc>isdethenzze. Infirstassumptinhiseffectscasdbytegometryofthenozzledduetothisthespcificfuiddynamcsofthegeratedplasaflow.T.1sowsacomarsnofspcificpasmapraeters,stadrdvs.improved<VMT>.按照我們研究的電流范圍,電弧電壓是最穩(wěn)定的。穩(wěn)定的電弧長(zhǎng)度表明噴嘴內(nèi)部陽(yáng)極〔電弧的穩(wěn)定情況。我們首先假定是幾何形噴嘴對(duì)陽(yáng)極的影響造成的。以及由此產(chǎn)生的等離子流的特殊流動(dòng)性,表1中是標(biāo)準(zhǔn)噴嘴及改進(jìn)后的噴嘴〔VMT,在特定等離子流參數(shù)下的對(duì)比情況。Tab.1comparisonofcharctrsticalpasaparmetersofthestanardadoptimizedrcss<VMT>表1：標(biāo)準(zhǔn)噴嘴及優(yōu)化噴嘴的等離子性能參數(shù)對(duì)比表StndrdVMTrgon/hdrognrtio4:14:1Electricalpwr[kW]Plasmaoltage[V]Voltagefluctuations[V]±22±11Thrmalefficiency[]標(biāo)準(zhǔn)噴嘴優(yōu)化后噴嘴/氫氣比率4:14:1電源[kW]等離子電壓[V]電壓波動(dòng)[V]±22±11熱效應(yīng)[]Testeris>Adjustmntofpaticlepopertis:testobjcts=spraysposandstrnsdevelopenttarget=aximiztionofDEandprsityadjstment試驗(yàn)b系列>顆粒性能調(diào)整:試驗(yàn)對(duì)象=噴涂點(diǎn)及噴涂行試驗(yàn)?zāi)繕?biāo)=將沉積率增加到最大,并實(shí)現(xiàn)孔隙率的調(diào)整Usngtheopimizedpasa-adinjctionprametrsfromtstseresa>,theprosityfrcostantcoatigdistaceecreaseselwtheminimalcceptedleve.Tocuntrt,theporsityisadjstedbyoptimiziggrainsizedistributionofthespraypowerandcoatigdistace.estadardsedYSZpwdrshwsagrainszedstributinof-12+22m<powderA>.Inordrtocieveahigerporosityevel,thefiefractionsrmovedandagrainszedstributinof-12+44μm<powderB>sdetermnedstheoptimmdistriution.Furthrmre,thecatigdistnceisoptimizdto160mm.Byadjustinghegrainszedistriution,theprsityisicresedfrm1%<pwdrA>toarquiredorsitylevelofaprox.2%<pwdrB>.采用試驗(yàn)a系列中的優(yōu)化等離子及注粉參數(shù),由于恒定噴涂距離的降低,孔隙率得以降到最低可接受水平。為了應(yīng)對(duì)此情況,通過(guò)優(yōu)化粉末顆粒的粒徑分布以及噴涂距離,可以對(duì)孔隙率進(jìn)行調(diào)節(jié)。標(biāo)準(zhǔn)工藝中使用的YSZ粉末的粒徑分布范圍為-12+22m<粉末A>.為了達(dá)到更高的孔隙率水平,去掉較細(xì)顆粒部分,我們決定采用-12+44μm〔粉末B作為優(yōu)化后的粒徑分布。此外,優(yōu)化后的噴涂距離為160mm。通過(guò)調(diào)整粒徑分布范圍,孔隙率從13%〔粉末A增加到所需的20%左右〔粉末B。Duetotheesntdevepmentrsults,itispssibetodedceanoptimizedaraetersetforcoatingofporusYSZwithsecifcporsitylevel.按照目前的研究結(jié)果,可以推導(dǎo)出通過(guò)優(yōu)化參數(shù)設(shè)置,達(dá)到Y(jié)SZ涂層所要求的孔隙率水平。Tocarctrizeteprticleroerties<velcity,temperatur>ofothcotingpraeters<stadd,improvd>SrayWachmasreentsrecrredou.Thecopativeanalssclrifiesadifferncenparticevelocity:fortheoptimizedcoaingparametrthevelocitysreucedbypprox.0m/scoparedtothestanardparmeter,Fg.7.通過(guò)Spraywatch對(duì)兩種噴涂參數(shù)〔標(biāo)準(zhǔn)及優(yōu)化后的進(jìn)行顆粒速度和溫度的測(cè)量。分析對(duì)比表明顆粒速度的區(qū)別為：如圖7所示,與標(biāo)準(zhǔn)工藝參數(shù)相比,優(yōu)化后噴涂參數(shù)的顆粒速度降低了大概10m/s.Themasurementsofarticletemeratrsshwsimilrvalsfrothprametrsatspecifccoatigdistacs,Fig.8.在噴涂距離一定的情況下,而所測(cè)量到的兩種參數(shù)的顆粒溫度結(jié)果差異不大,見(jiàn)圖8.Fig.7.comarisonofprticevelocityalngtheaxis,stanardvs.mprovdparameter圖7：標(biāo)準(zhǔn)及優(yōu)化參數(shù)的粉末顆粒速度對(duì)比圖,Fig.8.comprisnofpartcletemperaturealongtheaxis,stanardvs.improvdparmeter圖8：標(biāo)準(zhǔn)及優(yōu)化參數(shù)的粉末顆粒溫度對(duì)比圖,Theimrovdinnrnzzedsign<VTnzzl>ldstoadecelrtedplsmaet,whichrsultsinredcedparticeveloctycomparedtothestanardparmeter.Toralizeasimplifiedrobtmovementrocedreandtoredcetheprorammgeffortofcatingprogrmsforcoplexcomonntgeometres,norienatio-indeendntsingecoatigspotwsdeveloed.AnoverviewofthesersultsssowninTab.2.改進(jìn)后的內(nèi)孔噴嘴設(shè)計(jì)〔VMT噴嘴會(huì)導(dǎo)致等離子流速度的降低,因此相對(duì)標(biāo)準(zhǔn)參數(shù)而言,粉末顆粒的速度會(huì)相應(yīng)降低。為了達(dá)到簡(jiǎn)化機(jī)器人移動(dòng)程序以及降低復(fù)雜工件噴涂程序編程的難度,我們開(kāi)發(fā)了非定向單一噴涂點(diǎn)模式。通過(guò)表2可以查看相關(guān)結(jié)果。Tab.2.Coparsonstadardvs.imrovedcoatigparmetersforsecifccatingdistnce表2：噴距一定的情況下,標(biāo)準(zhǔn)與優(yōu)化后噴涂參數(shù)的對(duì)比效果表Testseriesc>Adjustmntofcotingespostion:testobjcts=coatingpatedevelopenttarget=oogeeosprosity試驗(yàn)C系列>涂層沉積的調(diào)整:試驗(yàn)對(duì)象=噴涂板研發(fā)目標(biāo)=均勻孔隙率Incntrstto"stanard"prcselopmensnthermalsprying,thetargetofthisevelopmntisfocsedonincrasngtheprocsefficiecybykeping<ntchangng>thecoatigprperti.Porsity,porositydstriutionndcatingthcknsshavetoecmparableandinthesaedefinedrngeforbothcoatingprcss.與熱噴涂中的"標(biāo)準(zhǔn)"工藝研發(fā)相比,本工藝研發(fā)的目標(biāo)是在保持〔不改變涂層性能的前提下,提高涂層生產(chǎn)效率。在相同的界定范圍內(nèi),對(duì)兩種工藝制備涂層的孔隙率,孔隙率分布以及涂層厚度進(jìn)行對(duì)比。Durngthecoatingrcs,thecoatigdepsitionisrealzedbyaverticaldsplcemntofstrngs.Arasofhighndwprsityreovrlapigandformacoatigwithaspcificporsitydistributinadporsityvalue.在噴涂過(guò)程中,涂層沉積通過(guò)噴涂行的垂直位移來(lái)實(shí)現(xiàn)。多孔和低孔區(qū)域相互疊加,并形成了一個(gè)有特殊孔隙率分布和孔隙率的涂層。Inordrtoachieveauniformporsitydistributinandvalue,plateswithdefindplasaaraeter<tstseres>>,njectincoditions,pwderadsraydistace<ttseresb>>arecatedwithdifferntoffsets.為了達(dá)到均勻的孔隙率分布和數(shù)值,我們按照特定的等離子參數(shù)〔試驗(yàn)a系列,注粉條件,粉末和噴涂距離〔試驗(yàn)b系列,采用不同的偏離值,對(duì)試驗(yàn)板進(jìn)行噴涂。Fortesngecatingstgeometre,averticaloffsetof 8mmand asubseqentpositive/ngtivedispacementof4mmforthestrtingpointofthefollowiglayrshstheoptimumrardigporostydistriutionndovrallorsity.Fig.8.sowsteinflueceoftheoffsettotheporsitydistribution.對(duì)于單個(gè)噴涂點(diǎn)的幾何形狀,8mm的垂直偏離以及下一涂層從起點(diǎn)位置的±4mm的位移,這些數(shù)據(jù)都顯示了孔隙率分布和疊加孔隙率的最佳情況。圖8顯示的是偏離對(duì)孔隙率分布的影響。Fig.8.influenceoftheofsettoporstydistributio,averaevaleandmin./maxvalues圖8：偏離對(duì)孔隙率分布,均值以及最大/最小值的影響示意圖Usngtheotimizedcoatngpraetrandcncptwithaicresedpowdrfederaterm80g/minto100g/mn,adepsitionefficiecyof>9%coprdto35%isreaized.采用優(yōu)化后的涂層參數(shù)及理念,送粉率從80g/min提高到100g/min,沉積率從35%提高到了59%。Acomprisonofqualiybetweenstanarddoptimizdocssgienbythecrssctinimags,Fig.9andFig.10.圖9和圖10顯示的是標(biāo)準(zhǔn)工藝和優(yōu)化后工藝的涂層質(zhì)量的截面對(duì)比圖Fig.9.Crsssctionimaeforstadardprcss,powderfedrate80g/min,DE35%圖9.送粉率80g/min,沉積率35%,采用標(biāo)準(zhǔn)噴涂工藝制備的涂層界面圖Fig.10.Crssctionimgeforoptimedprcs,powderfedrate100g/mi,DE>59%圖10.送粉率100g/min,沉積率>59%,采用優(yōu)化噴涂工藝制備的涂層界面圖Additionalaalysisofchnicalrpertisofbthcoatigsstms<stadr,improve>areonefrriskmitiationndtocmpretheechancalbehavirunerthermallod.對(duì)兩種工藝〔標(biāo)準(zhǔn)及優(yōu)化工藝所制備涂層的機(jī)械性能進(jìn)行分析,以便對(duì)這兩種涂層在熱負(fù)載下的機(jī)械性能進(jìn)行對(duì)比分析。ForhsCPsesreureentsrecared.ThICP sesrsstem measures curvature adtemperatureofsustratsdurigdpsitionadasodurigcooligdwnaftercoatig.Evlving,rsidlstrsssndelastcoduusofcoatinsreroviddbyrcorsetomesementofhesustraecurvatre[11.使用ICP傳感器進(jìn)行涂層機(jī)械性能測(cè)量。ICP傳感系統(tǒng)對(duì)基體在沉積及噴涂完成后冷卻過(guò)程中的彎曲度和溫度進(jìn)行了測(cè)量。通過(guò)涂層的變化應(yīng)力、殘余應(yīng)力和彈性模量等數(shù)值來(lái)對(duì)基體彎曲度進(jìn)行測(cè)量。Twotypesofstresssaredefindasfollwd:evolvingstrss:mchancalnnrstressswhhoccurdrigcoatigadresdualsrss:summatinofevolvingandthrmalstrssesescriesstrssstatusofthecoatig/sbsrate<aumim>systemafercoolngtoromtemperate.在此我們定義了以下兩種應(yīng)力：變化應(yīng)力和殘余應(yīng)力,變化應(yīng)力是指噴涂過(guò)程中的內(nèi)部機(jī)械應(yīng)力；而變化應(yīng)力和熱應(yīng)力的總和,就詮釋了涂層/基體〔鋁制系統(tǒng)冷卻到室溫過(guò)程中的應(yīng)力變化狀態(tài)。Bycomparonofbothsrsstypesfrthestanardandoptimzdcatingrcssitbcmesclertattheavergevaluesfreolvingadresiualstrssareredcdby50%fortheoptimizdrocess.通過(guò)標(biāo)準(zhǔn)工藝和優(yōu)化工藝的應(yīng)力類型對(duì)比情況,我們可以很清楚的看到優(yōu)化工藝所制備涂層的變化應(yīng)力和殘余應(yīng)力均值降幅達(dá)到了50%。AcomprisonoftheachieedvalusforevolvingandresdualstrssareshwnnFig.11.圖11顯示的是變化應(yīng)力和殘余應(yīng)力的測(cè)量值對(duì)比圖Fig.11.evolvingandrsdualstresssforstanardandoptimzdcoatigprcss圖11標(biāo)準(zhǔn)工藝和優(yōu)化工藝的變化應(yīng)力和殘余應(yīng)力對(duì)比圖Conctedto thesress masurements,temeasuredsubstrateteperatrsforbothcatigprcssesealosttesme<stanard=30,optimizd=40°C>.相對(duì)于應(yīng)力測(cè)量,對(duì)采用兩種不同工藝噴涂的基體所測(cè)量到的溫度差別不大〔標(biāo)準(zhǔn)工藝=350℃,優(yōu)化工藝=340℃。Formesrngthethmo-mcancalbhaviorofthecoatingsystemforechprametrset,samplsarecycldinisothrmalcnditiosupto250C.Tecurvatretmperatureolutionismonitoredoextracttheeasticehavirofthecoatngsystesninteractionwiththesbstrates.hecrvaturesurigheatingpareshwnnFig.12anddepctin