(1) Iimpawu zeBrazing iingxaki ezibandakanyekayo kwigrafiti kunye nedayimani polycrystalline brazing zifana kakhulu nezo zifunyanwa kwibrazing yeceramic. Xa kuthelekiswa nesinyithi, i-solder kunzima ukumanzisa igrafiti kunye nezinto ze-polycrystalline zedayimani, kwaye i-coefficient yayo yokwandiswa kobushushu yahlukile kakhulu kweyezinto zokwakha ngokubanzi. Ezi zimbini zifudunyezwa ngqo emoyeni, kwaye i-oxidation okanye i-carbonization iya kwenzeka xa ubushushu budlula i-400 ℃. Ke ngoko, i-vacuum brazing iya kwamkelwa, kwaye i-vacuum degree ayifanele ibe ngaphantsi kwe-10-1pa. Ngenxa yokuba amandla azo zombini akaphezulu, ukuba kukho uxinzelelo lobushushu ngexesha lebrazing, kunokuqhekeka. Zama ukukhetha isinyithi sebrazing filler esine-coefficient ephantsi yokwandiswa kobushushu kwaye ulawule ngokungqongqo izinga lokupholisa. Ekubeni umphezulu wezinto ezinjalo kungelula ukuba umanziswe ziintsimbi eziqhelekileyo zokuzalisa ibrazing, umaleko we-2.5 ~ 12.5um ubukhulu be-W, i-Mo kunye nezinye izinto zinokufakwa kumphezulu wezinto ze-graphite kunye ne-diamond polycrystalline ngokuguqulwa komphezulu (i-vacuum coating, i-ion sputtering, i-plasma spray kunye nezinye iindlela) ngaphambi kokuzalisa kwaye kwenziwe ii-carbides ezihambelana nazo, okanye iintsimbi zokuzalisa ibrazing ezisebenza kakhulu zingasetyenziswa.
I-Graphite kunye nedayimani zinamabakala amaninzi, ahluke ngobukhulu bamasuntswana, uxinano, ubumsulwa kunye nezinye izinto, kwaye zineempawu ezahlukeneyo zokurhawula. Ukongeza, ukuba ubushushu bezinto zedayimani ze-polycrystalline budlula i-1000 ℃, umlinganiselo wokurhawula we-polycrystalline uqala ukwehla, kwaye umlinganiselo wokurhawula uyancipha ngaphezulu kwe-50% xa ubushushu budlula i-1200 ℃. Ke ngoko, xa idayimani yokurhawula nge-vacuum, ubushushu bokurhawula kufuneka bulawulwe ngaphantsi kwe-1200 ℃, kwaye iqondo lokurhawula akufuneki libe ngaphantsi kwe-5 × 10-2Pa.
(2) Ukhetho lwentsimbi yokuzalisa ibrazing lusekelwe kakhulu ekusetyenzisweni nasekucutshungulweni komphezulu. Xa isetyenziswa njengesixhobo esingamelani nobushushu, intsimbi yokuzalisa ibrazing enobushushu obuphezulu bokuzalisa kunye nokumelana nobushushu okuhle kuya kukhethwa; Kwizinto ezimelana nokugqwala kweekhemikhali, kukhethwa iintsimbi zokuzalisa ibrazing ezinobushushu obuphantsi bokuzalisa kunye nokumelana nokugqwala okuhle. Kwi-graphite emva konyango lwe-surface metallization, i-solder yobhedu ecocekileyo ene-ductility ephezulu kunye nokumelana nokugqwala okuhle ingasetyenziswa. I-solder esebenzayo esekelwe kwisilivere kunye ne-copper inamandla okumanzi kunye nokuchaneka okuhle kwi-graphite kunye nedayimani, kodwa ubushushu benkonzo ye-brazed joint kunzima ukudlula i-400 ℃. Kwizixhobo ze-graphite kunye nezixhobo zedayimani ezisetyenziswa phakathi kwe-400 ℃ kunye ne-800 ℃, isiseko segolide, isiseko se-palladium, isiseko se-manganese okanye i-titanium base filler metals zihlala zisetyenziswa. Kwizihlanganisi ezisetyenziswa phakathi kwe-800 ℃ kunye ne-1000 ℃, kufuneka kusetyenziswe iintsimbi zokuzalisa ezisekelwe kwi-nickel okanye kwi-drill based filler metals. Xa kusetyenziswa izinto zegrafiti ezingaphezu kwe-1000 ℃, iintsimbi ze-pure metal filler metal (Ni, PD, Ti) okanye iintsimbi ze-alloy filler ezine-molybdenum, Mo, Ta kunye nezinye izinto ezinokwenza ii-carbides ngekhabhoni zingasetyenziswa.
Kwi-graphite okanye idayimani ngaphandle kokulungiswa komphezulu, iintsimbi ezisebenzayo zokuzalisa ezikwitheyibhile 16 zingasetyenziselwa ukurhawuzelela ngokuthe ngqo. Uninzi lwezi metals zokuzalisa zi-alloys ze-titanium ezisekelwe kwi-binary okanye kwi-ternary. I-titanium ecocekileyo isabela ngamandla kwi-graphite, enokwenza umaleko we-carbide otyebileyo kakhulu, kwaye i-coefficient yayo yokwandisa umgca yahlukile kakhulu kweye-graphite, elula ukuvelisa iintanda, ngoko ayinakusetyenziswa njenge-solder. Ukongezwa kwe-Cr kunye ne-Ni kwi-Ti kunokunciphisa i-melting point kwaye kuphucule ukumanzi nge-ceramics. I-Ti yi-alloy ye-ternary, eyenziwe kakhulu yi-Ti Zr, kunye nokongezwa kwe-TA, i-Nb kunye nezinye izinto. Ine-coefficient ephantsi yokwandisa umgca, enokunciphisa uxinzelelo lwe-brazing. I-alloy ye-ternary eyenziwe kakhulu yi-Ti Cu ifanelekile ukurhawuzelela i-graphite kunye nentsimbi, kwaye ijoyinti inokumelana nokugqwala okuphezulu.
Itheyibhile 16 ye-brazing filler metals ze-brazing ngqo ze-graphite kunye ne-diamond
(3) Inkqubo yokubraza, iindlela zokubraza zegrafiti zingahlulwa zibe ngamacandelo amabini, enye kukubraza emva kokubraza komphezulu, kwaye enye kukubraza ngaphandle konyango lomphezulu. Nokuba yeyiphi na indlela esetyenzisiweyo, ukuwelda kufuneka kulungiswe kwangaphambili ngaphambi kokuhlanganiswa, kwaye ungcoliseko lomphezulu wezinto zegrafiti kufuneka lusulwe ngotywala okanye i-acetone. Kwimeko yokubraza komphezulu, umaleko we-Ni, Cu okanye umaleko we-Ti, Zr okanye i-molybdenum disilicide kufuneka ugqunywe kumphezulu wegrafiti ngokutshiza ngeplasma, kwaye emva koko kusetyenziswe isinyithi esisekelwe kubhedu okanye isinyithi esisekelwe kwisilivere kwibrazing. Ukubraza ngqo nge-solder esebenzayo yeyona ndlela isetyenziswa kakhulu okwangoku. Ubushushu bobrazing bunokukhethwa ngokwe-solder enikiweyo kwitheyibhile 16. I-solder ingafakwa phakathi kwejoyinti ebrazing okanye kufutshane nesiphelo esinye. Xa kubrazwa ngesinyithi esine-coefficient enkulu yokwandiswa kobushushu, i-Mo okanye i-Ti enobukhulu obuthile ingasetyenziswa njengomaleko we-buffer ophakathi. Umaleko wotshintsho unokuvelisa ukuguqulwa kweplastiki ngexesha lokufudumeza ibrazing, ukufunxa uxinzelelo lobushushu kwaye kuthintele ukuqhekeka kwegrafithi. Umzekelo, iMo isetyenziswa njenge-transition joint ye-vacuum brazing ye-graphite kunye ne-hastelloyn components. I-B-pd60ni35cr5 solder enokumelana kakuhle nokugqwala kwetyuwa enyibilikisiweyo kunye nemitha iyasetyenziswa. Ubushushu bebrazing yi-1260 ℃ kwaye ubushushu bugcinwa imizuzu eli-10.
Idayimani yendalo ingafakwa ngqo kwi-brazing nge-b-ag68.8cu16.7ti4.5, b-ag66cu26ti8 kunye nezinye ii-solders ezisebenzayo. I-brazing mayiqhutywe phantsi kokhuseleko lwe-vacuum okanye i-argon ephantsi. Ubushushu be-brazing akufuneki budlule kwi-850 ℃, kwaye kufuneka kukhethwe izinga lokufudumeza elikhawulezayo. Ixesha lokubamba kubushushu be-brazing akufuneki libe lide kakhulu (ngokubanzi malunga ne-10s) ukuze kuthintelwe ukwakheka komaleko we-tic oqhubekayo kwindawo yokujonga. Xa kufakwa idayimani kunye nentsimbi ye-alloy, kufuneka kongezwe umaleko weplastiki okanye umaleko we-alloy ophantsi ukuze kutshintshelwe ukuthintela umonakalo weenkozo zedayimani obangelwa kuxinzelelo olukhulu lobushushu. Isixhobo sokujika okanye isixhobo sokubhoboza somatshini wokuchwetheza ngokuchanekileyo kakhulu senziwa yinkqubo ye-brazing, efaka idayimani encinci engama-20 ~ 100mg emzimbeni wentsimbi, kwaye amandla adibeneyo ejoyinti ye-brazing afikelela kwi-200 ~ 250mpa.
Idayimani yePolycrystalline ingafakwa ibrashi ngelangatye, i-frequency ephezulu okanye i-vacuum. I-brashi ephezulu okanye i-flame brashi kufuneka isetyenziswe kwisinyithi okanye ilitye lesarha elijikelezayo ledayimani. Isinyithi esisebenzayo se-Ag Cu Ti esine-low melting point kufuneka sikhethwe. Ubushushu be-brashi buya kulawulwa ngaphantsi kwe-850 ℃, ixesha lokufudumeza aliyi kuba lide kakhulu, kwaye izinga lokuphola elicothayo liya kusetyenziswa. Iibhithi zedayimani zePolycrystalline ezisetyenziswa kwi-petroleum nakwi-geological drilling zineemeko zokusebenza ezimbi kwaye zithwala imithwalo emikhulu yempembelelo. Isinyithi se-brazing based brazing filler sinokukhethwa kwaye i-copper foil ecocekileyo ingasetyenziswa njengomaleko we-vacuum brazing. Umzekelo, ii-capsules ezingama-350 ~ 400 Ф 4.5 ~ 4.5mm columnar polycrystalline diamond zifakwe kwi-perforations ye-35CrMo okanye i-40CrNiMo steel ukwenza amazinyo okusika. Ukuqhoboshela nge-vacuum brazing kuyamkelwa, kwaye i-vacuum degree ayingaphantsi kwe-5 × 10-2Pa, ubushushu boqhoboshela yi-1020 ± 5 ℃, ixesha lokubamba yi-20 ± 2min, kwaye amandla okucheba ejoyinti yokuqhoboshela makhulu kune-200mpa.
Ngexesha lokurhawuzelela, ubunzima bokurhawuzelela kufuneka busetyenziswe ekuhlanganiseni nasekubekeni indawo kangangoko kunokwenzeka ukuze inxalenye yesinyithi icinezele i-graphite okanye i-polycrystalline material kwinxalenye ephezulu. Xa usebenzisa i-fixture ukubeka indawo, i-fixture material kufuneka ibe yi-material ene-thermal expansion coefficient efana neye-weldment.
Ixesha lokuthumela: Juni-13-2022