I-Sapphire yinto enzima, ekwaziyo ukunxiba kwaye inamandla kunye nobushushu obunyibilikayo obuphezulu, inert yekhemikhali ngokubanzi, kwaye ibonisa iimpawu ezinomdla zamehlo. Ke ngoko, isafire isetyenziselwa usetyenziso oluninzi lwetekhnoloji apho awona mmandla uphambili kushishino optics kunye ne-elektroniki. Namhlanje elona candelo likhulu lesafire yeshishini lisetyenziswa njenge-substrate ye-LED kunye nemveliso ye-semiconductor, ilandelwa kusetyenziswa njengeefestile zeewotshi, iinxalenye zefowuni ephathwayo okanye izikena zekhowudi yebha, ukukhankanya imizekelo embalwa [1]. Namhlanje, iindlela ezahlukeneyo zokukhulisa iikristale zesafire enye ziyafumaneka, ujongo olulungileyo lunokufunyanwa umz. kwi [1, 2]. Nangona kunjalo, iindlela ezintathu ezikhulayo ze-Kyropoulos process (KY), indlela yokutshintsha ukushisa (HEM) kunye ne-edged-defined film-fed growth (EFG) i-akhawunti engaphezu kwe-90 % yamandla okuvelisa isafire emhlabeni jikelele.
Umzamo wokuqala wekristale eyenziwe ngokwenziwa yenziwe ngo-1877 kwiikristale ezincinci zerubhi enye [2]. Ngokukhawuleza kwi-1926 inkqubo yeKyropoulos yaqanjwa. Isebenza kwi-vacuum kwaye ivumela ukuvelisa ii-boules ezinkulu ze-cylindrical shape ezikumgangatho ophezulu kakhulu. Enye indlela enomdla yokukhulisa isafire kukukhula okuchazwe kumda wefilimu. Ubuchule be-EFG busekelwe kumjelo we-capillary ozaliswe yi-liquid-melt kwaye ivumela ukukhulisa iikristale zesafire ezimile njengeentonga, iityhubhu okanye amashiti (ekwabizwa ngokuba ziiribhoni). Ngokwahlukileyo kwezi ndlela indlela yokutshintshiselana ngobushushu, eyazalwa ngasekupheleni kweminyaka yee-1960, ivumela ukuba kukhule iibhowuli ezinkulu zesafire ngaphakathi kwi-spun crucible emile kwi-crucible ngokutsalwa kobushushu obuchaziweyo ukusuka ezantsi. Ngenxa yokuba i-sapphire boule inamathele kwi-crucible ekupheleni kwenkqubo yokukhula, iibhondi zinokuqhekeka kwinkqubo epholileyo kwaye i-crucible ingasetyenziswa kanye kuphela.
Nabuphi na obu bugcisa bokukhula kwekristale yesafire bufana ukuba amacandelo angundoqo - ngakumbi ama-crucibles - afuna iintsimbi eziphikisayo zobushushu obuphezulu. Ngokuxhomekeke kwindlela yokukhula, ii-crucibles zenziwe nge-molybdenum okanye i-tungsten, kodwa iintsimbi zisetyenziselwa ukuxhathisa izifudumezi, iipakethi zokufa kunye nezikhuselo ze-hot-zone [1]. Nangona kunjalo, kweli phepha sigxininise kwingxoxo yethu kwi-KY kunye ne-EFG izihloko ezinxulumene noko kuba ii-crucibles ezicinezelekileyo zisetyenziswa kwezi nkqubo.
Kule ngxelo sibonisa izifundo zokubonisa iimpawu kunye nophando malunga nokulungiswa komphezulu wezinto ezicinezelweyo ezifana ne-molybdenum (Mo), i-tungsten (W) kunye ne-alloys yayo (MoW). Kwinxalenye yokuqala ugxininiso lwethu lulele kwidatha yomatshini wobushushu obuphezulu kunye ne-ductile ukuya kwi-brittle utshintsho lobushushu. Ukuncedisana neempawu zoomatshini siye safunda iimpawu ze-thermo-physical, oko kukuthi i-coefficient yokwandiswa kwe-thermal kunye ne-thermal conductivity. Kwicandelo lesibini sibonisa izifundo kwi-surface conditioning technique ngokukodwa ukuphucula ukuchasana kwee-crucibles ezizaliswe nge-alumina melt. Kwisiqingatha sesithathu sinika ingxelo ngemilinganiselo yee-engile zokumanzisa ze-alumina elulwelo kwiintsimbi ezilahlayo kwi-2100 °C. Senze imifuniselo ye-melt-drop kwi-Mo, W kunye ne-MoW25 alloy (75 wt.% molybdenum, 25 wt.% tungsten) kwaye sifunde ukuxhomekeka kwiimeko ezahlukeneyo zomoya. Ngenxa yophando lwethu sicebisa i-MoW njengesixhobo esinomdla kubuchwephesha bokukhula kwesafire nanjengenye enokuthi ibe kho kwimolybdenum emsulwa kunye netungsten.
Ubushushu obuphezulu bomatshini kunye neempawu ze-thermo-physical
Iindlela zokukhula kwekristale yesafire i-KY kunye ne-EFG zisebenza ngokulula ngaphezulu kwe-85% yesabelo sobungakanani besafire yehlabathi. Kuzo zombini iindlela, i-alumina yolwelo ifakwe kwii-crucibles ezicinezelekileyo, ezenziwe nge-tungsten yenkqubo ye-KY kwaye yenziwe nge-molybdenum yenkqubo ye-EFG. Ii-crucibles ziyinxalenye yenkqubo ebalulekileyo kwezi nkqubo zokukhula. Sijonge ingcamango ekunokwenzeka ukuba yehlise iindleko ze-tungsten crucibles kwinkqubo ye-KY kunye nokwandisa ubomi be-molybdenum crucibles kwinkqubo ye-EFG, sivelise kwaye savavanya ii-alloys ezimbini ze-MoW, okt i-MoW30 equlethe i-70 wt.% Mo kunye ne-30 wt. I-% W kunye ne-MoW50 iqulethe i-50 wt.% i-Mo kunye ne-W nganye.
Kuwo onke amaphononongo ophawu lwemathiriyeli sivelise ii-ingots ezicinezelweyo ze-Mo, i-MoW30, i-MoW50 kunye ne-W. Itheyibhile I ibonisa ukuxinana kunye nobukhulu obuziinkozo obuqhelekileyo obuhambelana neendawo zokuqala eziphathekayo.
Itheyibhile I: Isishwankathelo sezinto ezicinezelweyo-sintered ezisetyenziselwa imilinganiselo kwiipropati zomatshini kunye ne-thermo-physical. Itheyibhile ibonisa ukuxinana kunye nobukhulu obuyinkozo obuqhelekileyo beemeko zokuqala zezixhobo
Ngenxa yokuba ii-crucibles zisesichengeni sexesha elide kumaqondo obushushu aphezulu, siye saqhuba iimvavanyo ze-tensile ezicacileyo ngakumbi kuluhlu lwamaqondo obushushu aphezulu phakathi kwe-1000 °C kunye ne-2100 °C. Isazobe soku-1 sishwankathela ezi ziphumo ze-Mo, i-MoW30, kunye ne-MoW50 apho i-0.2 % yamandla esivuno (Rp0.2) kunye nokwandiswa kokwaphuka (A) kubonisiwe. Ukuthelekisa, indawo yedatha ye-pressed-sintered W iboniswe kwi-2100 ° C.
Ukwenzela i-tungsten eqinileyo ene-soluted kwi-molybdenum i-Rp0.2 kulindeleke ukuba inyuke xa ithelekiswa nezinto ezicocekileyo ze-Mo. Kumaqondo obushushu ukuya kuthi ga kwi-1800 °C zombini iialloyi ze-MoW zibonisa ubuncinane amaxesha ama-2 aphezulu nge-Rp0.2 kune-Mo, bona uMfanekiso 1(a). Kubushushu obuphezulu kuphela i-MoW50 ebonisa i-Rp0.2 ephuculwe kakhulu. Icinezelwe-sintered W ibonisa eyona Rp0.2 iphezulu kwi-2100 °C. Iimvavanyo zokuqina zityhila kwakhona u-A njengoko kubonisiwe kuMfanekiso 1(b). Zombini iialloyi ze-MoW zibonisa ubude obufana kakhulu kumaxabiso okuqhekezwa aqheleke abe sisiqingatha samaxabiso e-Mo. I-A ephezulu ngokwentelekiso ye-tungsten kwi-2100 °C kufuneka ibangwe bubume bayo obucolekileyo kakhulu xa kuthelekiswa ne-Mo.
Ukumisela i-ductile ukuya kwi-brittle transition yeqondo lokushisa (DBTT) ye-alloys ye-molybdenum tungsten ecinezelekileyo, kunye nemilinganiselo kwi-engile yokugoba yaqhutywa kumaqondo okushisa ahlukeneyo. Iziphumo ziboniswe kuMfanekiso 2. I-DBTT iyanda ngokunyusa umxholo we-tungsten. Ngelixa i-DBTT ye-Mo isezantsi kakhulu malunga ne-250 °C, i-alloys i-MoW30 kunye ne-MoW50 zibonisa i-DBTT emalunga ne-450 °C kunye ne-550 °C, ngokulandelelanayo.
Ukuhambelana neempawu zoomatshini siye safunda neempawu ze-thermo-physical. I-coefficient of thermal expansion (CTE) yalinganiswa kwi-push-rod dilatometer [3] kwiqondo lokushisa ukuya kwi-1600 °C usebenzisa i-specimen ene-Ø5 mm kunye ne-25 mm ubude. Imilinganiselo ye-CTE ibonakaliswe kwi-Figure 3. Zonke izixhobo zibonisa ukuxhomekeka okufanayo kakhulu kwe-CTE ngokunyuka kweqondo lokushisa. Amaxabiso e-CTE kwii-alloys ze-MoW30 kunye ne-MoW50 ziphakathi kwamaxabiso e-Mo kunye ne-W. Ngenxa yokuba i-porosity eshiyekileyo yezinto ezicinezelekileyo zi-discontiguous kunye ne-pores encinci yomntu, i-CTE efunyenweyo ifana nemathiriyeli ephezulu yoxinaniso njengamaphepha kunye iintonga [4].
I-conductivity ye-thermal ye-pressed-sintered materials yafunyanwa ngokulinganisa zombini i-thermal diffusivity kunye nobushushu obuthile be-specimen kunye ne-Ø12.7 mm kunye ne-3.5 mm ubukhulu usebenzisa indlela ye-laser flash [5, 6]. Kwizinto ze-isotropic, ezifana ne-pressed-sintered materials, ubushushu obuthile bunokulinganiswa ngendlela efanayo. Imilinganiselo ithathwe kuluhlu lobushushu obuphakathi kwe-25 °C kunye ne-1000 °C. Ukubala i-thermal conductivity esetyenzisiweyo ukongeza ukuxinana kwezinto ezibonakalayo njengoko kubonisiwe kwiThebhile I kwaye sithatha ubushushu obuzimeleyo obuzimeleyo. Umzobo we-4 ubonisa isiphumo se-thermal conductivity ye-pressed-sintered Mo, i-MoW30, i-MoW50 kunye ne-W. I-thermal conductivity
I-alloys ye-MoW ingaphantsi kwe-100 W/mK kuwo onke amaqondo obushushu aphandiweyo kwaye mancinci kakhulu xa kuthelekiswa ne-molybdenum ecocekileyo kunye ne-tungsten. Ukongeza, i-conductivity ye-Mo kunye ne-W iyancipha ngokunyuka kweqondo lokushisa ngelixa i-conductivity ye-alloy ye-MoW ibonisa amaxabiso anyukayo ngokunyuka kweqondo lokushisa.
Isizathu salo mahluko asikhange siphandwe kulo msebenzi kwaye siya kuba yinxalenye yophando lwexesha elizayo. Kuyaziwa ukuba isinyithi inxalenye elawulayo ye-thermal conductivity kumaqondo aphantsi obushushu ligalelo le-phonon ngelixa kumaqondo obushushu aphezulu igesi ye-electron ilawula i-thermal conductivity [7]. Iifowuni zichatshazelwa kukungafezeki kwezinto kunye neziphene. Nangona kunjalo, ukwanda kwe-thermal conductivity kuluhlu oluphantsi lobushushu alujongwa kuphela kwi-alloys ye-MoW kodwa kunye nezinye izinto eziqinileyo ezifana ne-tungsten-rhenium [8], apho igalelo le-electron lidlala indima ebalulekileyo.
Ukuthelekiswa komatshini kunye neempawu ze-thermo-physical kubonisa ukuba i-MoW yinto enomdla kwizicelo zesafire. Kumaqondo obushushu aphezulu> 2000 °C amandla esivuno angaphezulu kwe-molybdenum kwaye ubomi obude be-crucibles kufuneka bube nokwenzeka. Nangona kunjalo, izinto eziphathekayo ziba brittle kwaye umatshini kunye nokuphathwa kufuneka kulungiswe. Ukunciphisa kakhulu ukuhanjiswa kwe-thermal ye-MoW ecinezelekileyo njengoko kubonisiwe kuMfanekiso 4 kubonisa ukuba iparamitha ezilungelelanisiweyo zokufudumeza kunye nokupholisa phantsi kwesithando somlilo esikhulayo kunokuba yimfuneko. Ngokukodwa kwisigaba sokushisa, apho i-alumina idinga ukuncibilika kwi-crucible, ukushisa kuhanjiswa kuphela nge-crucible kwizinto zayo zokuzalisa eluhlaza. Ukunciphisa i-thermal conductivity ye-MoW kufuneka kuthathelwe ingqalelo ukuphepha uxinzelelo oluphezulu lwe-thermal kwi-crucible. Uluhlu lwemilinganiselo ye-CTE ye-alloys ye-MoW inomdla kumxholo we-HEM ye-crystal yokukhula indlela. Njengoko kuxoxiwe kwireferensi [9] i-CTE ye-Mo ibangela ukuba i-clamping yesafire kwinqanaba elipholileyo. Ke ngoko, i-CTE encitshisiweyo ye-alloy ye-MoW inokuba sisitshixo sokuqonda ii-crucibles spun eziphinda zisetyenziswe kwinkqubo ye-HEM.
Ukulungiswa komphezulu wentsimbi ecinezelweyo-sintered refractory
Njengoko kuxoxwe kwintshayelelo, ii-crucibles-pressed-sintered crucibles zihlala zisetyenziswa kwiinkqubo zokukhula kwekristale yesafire ukufudumeza kwaye ugcine i-alumina inyibilika kancinci ngaphezulu kwe-2050 °C. Enye imfuneko ebalulekileyo kumgangatho wokugqibela wekristale yesafire kukugcina ukungcola kunye namaqamza erhasi ekunyibilikeni asezantsi kangangoko. Amalungu acinezelweyo ane-porosity eshiyekileyo kwaye abonisa ulwakhiwo olucolekileyo. Esi sakhiwo sicolekileyo esine-porosity evaliweyo si-ethe-ethe kwi-orrosion ephuculweyo yesinyithi ngakumbi ngokunyibilika kwe-oxidic. Enye ingxaki yeekristale zesafire ngamaqamza amancinci egesi ngaphakathi kokunyibilika. Ukubunjwa kwamaqamza erhasi kuphuculwa ngokunyuka koburhabaxa bomphezulu bendawo echasayo edityaniswe nenyibilika.
Ukoyisa le miba yemathiriyeli ecinezelweyo-sintered sisebenzisa unyango oluphezulu lomatshini. Sivavanye indlela ngesixhobo sokucinezela apho isixhobo se-ceramic sisebenza phezulu phantsi koxinzelelo oluchaziweyo lwenxalenye ecinezelweyo-sintered [10]. Uxinzelelo olusebenzayo olucinezelayo kumphezulu luchanekile kuxhomekeke kwindawo yokunxibelelana yesixhobo se-ceramic ngexesha lokulungiswa komphezulu. Ngolu nyango uxinzelelo oluphezulu lunokuthi lusetyenziswe kwindawo kwindawo yezixhobo ezicinezelekileyo kunye nomgangatho wezinto eziphathekayo ukhubazekile ngeplastiki. Umzobo wesi-5 ubonisa umzekelo wesampulu yemolybdenum ecinezelweyo esetyenzisiweyo ngobu buchule.
Umzobo we-6 ubonisa ngokusemgangathweni ukuxhomekeka koxinzelelo olusebenzayo kuxinzelelo lwesixhobo. Idatha ithathwe kwimilinganiselo ye-static imprints yesixhobo kwi-pressed-sintered molybdenum. Umgca ubonisa ukufaneleka kwedatha ngokwemodeli yethu.
Umzobo 7 ubonisa iziphumo zokuhlalutya ezishwankathelweyo ngoburhabaxa bomphezulu kunye nemilinganiselo yobulukhuni bomhlaba njengomsebenzi woxinzelelo lwesixhobo sezinto ezahlukeneyo ezicinezelweyo ezilungiselelwe njengediski. Njengoko kuboniswe kuMfanekiso 7 (a) unyango lubangela ukuqina komphezulu. Ukuqina kwezixhobo zombini ezivavanyiweyo i-Mo kunye ne-MoW30 yonyuka malunga ne-150%. Kuxinzelelo lwesixhobo esiphakamileyo ukuqina abunyuki ngakumbi. Umfanekiso 7(b) ubonisa ukuba iindawo ezigudileyo kakhulu ezineRa eziphantsi njenge-0.1 μm ye-Mo zinokwenzeka. Ukunyusa uxinzelelo lwesixhobo uburhabaxa be-Mo buyanda kwakhona. Ngenxa yokuba i-MoW30 (kunye ne-W) zizixhobo ezilukhuni kune-Mo, ixabiso le-Ra elifunyenweyo le-MoW30 kunye ne-W liphezulu ngokuphindwe ka-2-3 ngaphezu kwe-Mo. Ngokuchasene ne-Mo, uburhabaxa bomphezulu be-W buyancipha ngokusebenzisa uxinzelelo oluphezulu lwezixhobo ngaphakathi uluhlu lweparameter evavanyiweyo.
Uphononongo lwethu lwe-electron microscopy (SEM) yokuskena kwemiphezulu eqingqiweyo iqinisekisa idatha yobunzima bomphezulu, jonga uMzobo 7(b). Njengoko kubonisiwe kuMfanekiso 8(a), ngokukodwa uxinzelelo oluphezulu lwezixhobo lunokukhokelela ekonakaleni komphezulu weenkozo kunye ne-microcracks. Ukulungiswa koxinzelelo oluphezulu kakhulu kumphezulu kunokubangela nokususwa kweenkozo kumphezulu, jonga uMzobo 8(b). Iziphumo ezifanayo zinokujongwa kwi-MoW kunye ne-W kwiiparamitha ezithile zomatshini.
Ukuphonononga isiphumo sobuchule bokulungisa umphezulu ngokubhekiselele kubume benkozo engaphezulu kunye nokuziphatha kwayo kobushushu, silungiselele iisampulu zokucoca kwiidiski zovavanyo ezintathu ze-Mo, MoW30 kunye ne-W.
Iisampulu zaphathwa ngeeyure ze-2 kumaqondo okushisa ahlukeneyo kwi-800 ° C ukuya kwi-2000 ° C kunye ne-microsections yalungiselelwa uhlalutyo lwe-microscopy yokukhanya.
Umzobo we-9 ubonisa imizekelo ye-microsection ye-molybdenum ecinezelekileyo. Imeko yokuqala yendawo ephathwayo iboniswe kuMfanekiso 9 (a). Umphezulu ubonisa umaleko ophantse washinyana phakathi koluhlu olumalunga nama-200 μm. Ngezantsi kolu luhlu lwesakhiwo sezinto eziqhelekileyo kunye ne-sintering pores ibonakala, i-porosity eseleyo malunga ne-5%. I-porosity eseleyo elinganisiweyo ngaphakathi kwendawo engaphezulu ingaphantsi kwe-1%. Umzobo 9(b) ubonisa ubume beenkozo emva kokufakwa kwe-2 h kwi-1700 °C. Ubunzima bomaleko oxineneyo womphezulu bunyukile kwaye iinkozo zinkulu kakhulu kuneenkozo ezikwivolumu engalungiswanga ngokulungiswa komphezulu. Lo maleko oshinyeneyo ocoarse-grained uya kusebenza kakuhle ekuphuculeni ukuxhathisa kwe-creep yezinto.
Sifunde ukuxhomekeka kobushushu bomaleko womphezulu ngokumalunga nobukhulu kunye nobungakanani beenkozo zoxinzelelo lwezixhobo ezahlukeneyo. Umzobo we-10 ubonisa imizekelo emeleyo yobukhulu bomaleko womphezulu we-Mo kunye ne-MoW30. Njengoko kubonisiwe kuMfanekiso we-10(a) ubukhulu bokuqala bomaleko womphezulu buxhomekeke kulungiselelo lwesixhobo somatshini. Kwiqondo lobushushu le-anneal elingaphezulu kwe-800 °C ubukhulu bomgangatho we-Mo buqala ukwanda. Kwi-2000 ° C ubukhulu bomaleko bufikelela kumaxabiso e-0.3 ukuya kwi-0.7 mm. Kwi-MoW30 ukwanda kobunzima bomaleko womphezulu kunokujongwa kuphela kumaqondo obushushu angaphezu kwe-1500 °C njengoko kubonisiwe kuMfanekiso 10(b). Nangona kunjalo kwi-2000 °C ubukhulu be-MoW30 bufana kakhulu ne-Mo.
Njengohlalutyo lobungqingqwa bomaleko womphezulu, uMzobo we-11 ubonisa umndilili wedatha yobungakanani beenkozo ze-Mo kunye ne-MoW30 ezilinganiswe kumaleko womphezulu njengomsebenzi wamaqondo obushushu obushushu. Njengoko kunokuchazwa kumanani, ubungakanani beenkozo - ngaphakathi komlinganiselo wokungaqiniseki - ozimeleyo kwi-parameter setup esetyenzisiweyo. Ukukhula kobungakanani beenkozo kubonisa ukukhula okungaqhelekanga kweenkozo zomaleko womphezulu obangelwa kukuguqulwa kommandla womphezulu. Iinkozo ze-molybdenum zikhula kumaqondo obushushu ovavanyo angaphezu kwe-1100 °C kwaye ubungakanani beenkozo buphantse buphindwe ka-3 ubukhulu kwi-2000 °C xa kuthelekiswa nobukhulu bokuqala beenkozo. Iinkozo ze-MoW30 zomaleko okwimeko esemgangathweni ziqala ukukhula ngaphezu kobushushu obuyi-1500 °C. Kwiqondo lobushushu lovavanyo lwe-2000 °C umyinge wobungakanani beenkozo malunga namaxesha ama-2 ubukhulu bengqolowa yokuqala.
Ngamafutshane, uphando lwethu kubuchule bokulungisa umphezulu bubonisa ukuba isebenza kakuhle kwiingxubevange ze-molybdenum tungsten ecinezelweyo. Ukusebenzisa le ndlela, iindawo ezinobunzima obuninzi kunye nemigangatho egudileyo kunye neRa kakuhle ngaphantsi kwe-0.5 μm inokufumaneka. Ipropathi yokugqibela iluncedo ngakumbi ekunciphiseni amaqamza erhasi. I-porosity eshiyekileyo kwi-surface layer isondele kwi-zero. Uphononongo lwe-Anealing kunye ne-microsection lubonisa ukuba umaleko oxineneyo kakhulu womgangatho kunye nobukhulu obuqhelekileyo be-500 μm unokufumaneka. Ngale ndlela iparamitha yomatshini inokulawula ubukhulu bomaleko. Xa ubeka izinto ezibekwe kwimeko yobushushu obuphezulu njengesiqhelo esetyenziswa kwiindlela zokukhulisa isafire, umaleko womphezulu uba rhabaxa-grained kunye nobukhulu obuziinkozo obuphindwe ka-2-3 kunokuba ngaphandle komatshini womphezulu. Ubungakanani obuziinkozo kumqolo ongaphezulu buxhomekeke kwiiparamitha zomatshini. Inani lemida yeenkozo kumphezulu liyancipha ngokufanelekileyo. Oku kukhokelela kuxhathiso oluphezulu ngokuchasene nokusasazwa kwezinto ecaleni kwemida yeenkozo kwaye uhlaselo lokunyibilika lusezantsi. Ukongeza, ukuxhathisa kweqondo lobushushu eliphezulu lokucinezelwa-sintered molybdenum tungsten alloys kuyaphuculwa.
Uphononongo lokumanzisa lwe-alumina elulwelo kwiintsimbi ezichasayo
Ukumanzisa kwealumina elulwelo kwimolybdenum okanye itungsten ngundoqo womdla kushishino lwesafire. Ngokukodwa kwinkqubo ye-EFG i-alumina yokumanzisa ukuziphatha kwi-die-pack capillaries imisela izinga lokukhula kweentonga zesafire okanye iiribhoni. Ukuqonda impembelelo yezinto ezikhethiweyo, uburhabaxa bomphezulu okanye umoya wenkqubo senze imilinganiselo ye-angle yokumanzisa eneenkcukacha [11].
Uvavanyo lwemilinganiselo yokumanzisa iisubstrates ezinobungakanani be-1 x 5 x 40 mm³ zaveliswa kwi-Mo, MoW25 kunye ne-W sheet materials. Ngokuthumela umbane ophezulu wangoku ngokusebenzisa i-substrate ye-metal sheet ubushushu obunyibilikayo be-alumina ye-2050 °C bunokufezekiswa kwisiqingatha somzuzu. Kwimilinganiselo ye-angle amaqhekeza amancinci e-alumina abekwe phezu kweesampuli zephepha kwaye emva koko
yanyibilika yaba ngamathontsi. Isixokelelwano esizenzekelayo sokucinga sirekhode ithontsi elinyibilikayo njengoko kubonisiwe ngokomzekelo kuMfanekiso 12. Umfuniselo ngamnye wokunyibilika uvumela ukulinganisa i-angle yokumanzisa ngokuhlalutya i-contour ye-droplet, jonga uMzobo 12(a), kunye nesiseko se-substrate ngokuqhelekileyo emva nje kokucima ukufudumeza okwangoku, jonga uMfanekiso 12(b).
Senze imilinganiselo ye-angle yokumanzisa kwiimeko ezimbini ezahlukeneyo ze-atmosphere, i-vacuum kwi-10-5mbar kunye ne-argon kwi-900 mbar yoxinzelelo. Ukongeza, iindidi ezimbini zomphezulu zavavanywa, okt iindawo ezirhabaxa ezineRa ~ 1 μm kunye neendawo ezigudileyo ezineRa ~ 0.1 μm.
Itheyibhile II ishwankathela iziphumo zayo yonke imilinganiselo kwii-engile zokumanzisa i-Mo, i-MoW25 kunye ne-W yeendawo ezigudileyo. Ngokubanzi, i-angle yokumanzisa ye-Mo incinci xa kuthelekiswa nezinye izinto. Oku kuthetha ukuba i-alumina inyibilika imanzisa iMo eyona nto iluncedo kubuchule bokukhula be-EFG. Ii-angles zokumanzisa ezifunyenwe kwi-argon ziphantsi kakhulu kuneengile ze-vacuum. Kwimigangatho erhabaxa yesubstrate sifumana ngokucwangcisiweyo ii-engile zokumanzisa ezisezantsi. La maxabiso aqhelekile malunga ne-2° ngaphantsi kwee-engile ezinikwe kwiTheyibhile II. Nangona kunjalo, ngenxa yokungaqiniseki komlinganiselo, akukho mahluko ubalulekileyo we-engile phakathi kweendawo ezigudileyo nezirhabaxa ezinokuxelwa.
Silinganise ii-engile zokumanzisa nezinye ii-atmosphere, okt amanani aphakathi kwe-10-5 mbar kunye ne-900 mbar. Uhlalutyo lokuqala lubonisa ukuba ngenxa yoxinzelelo phakathi kwe-10-5 mbar kunye ne-1 mbar ingelosi yokumanzisa ayitshintshi. Kuphela ngaphezu kwe-1 mbar i-angle yokumanzisa iba ngaphantsi kunokuba ibonwe kwi-900 mbar argon (Itheyibhile II). Ngaphandle kwemeko ye-atmospheric, enye into ebalulekileyo ekuziphatheni okumanzi kwe-alumina enyibilikayo luxinzelelo oluyinxenye yeoksijini. Iimvavanyo zethu zibonisa ukuba ukusebenzisana kweekhemikhali phakathi kwe-melt kunye ne-metal substrates kwenzeka ngexesha elipheleleyo lokulinganisa (ngokuqhelekileyo i-1 iminithi). Sikrokrela iinkqubo zokunyibilika kweeamolekyuli ze-Al2O3 kwezinye iinxalenye ze-oksijini ezisebenzisana ne-substrate material kufuphi ne-droplet enyibilikayo. Uphononongo olongezelelweyo ngoku luyaqhubeka ukuphanda ngokweenkcukacha ezithe vetshe zombini ukuxhomekeka koxinzelelo lwe-engile yokumanzisa kunye nokunxibelelana kweekhemikhali zokunyibilika ngeentsimbi ezilahlayo.
Ixesha lokuposa: Jun-04-2020