(1) Makhalidwe a brazing mavuto omwe amapezeka mu graphite ndi diamondi polycrystalline brazing ndi ofanana kwambiri ndi omwe amakumana nawo mu ceramic brazing.Poyerekeza ndi zitsulo, solder ndizovuta kunyowetsa graphite ndi diamondi polycrystalline zida, ndipo coefficient yake ya kukulitsa matenthedwe ndi yosiyana kwambiri ndi yazinthu zambiri zamapangidwe.Awiriwo amatenthedwa mwachindunji mumlengalenga, ndipo makutidwe ndi okosijeni kapena carbonization idzachitika pamene kutentha kupitirira 400 ℃.Chifukwa chake, kupukuta kwa vacuum kudzakhazikitsidwa, ndipo digiri ya vacuum sikhala yochepera 10-1pa.Chifukwa mphamvu zonse ziwiri sizokwera, ngati pali kupsinjika kwa kutentha panthawi ya brazing, ming'alu imatha kuchitika.Yesani kusankha brazing filler chitsulo chokhala ndi coefficient yotsika yakukulitsa kutentha ndikuwongolera kuzizira.Popeza pamwamba pa zinthu zotere sikophweka kunyowetsedwa ndi zitsulo wamba wa brazing filler, wosanjikiza wa 2.5 ~ 12.5um wandiweyani W, Mo ndi zinthu zina zitha kuyikidwa pamwamba pa zida za graphite ndi diamondi polycrystalline posintha pamwamba (kuyika vacuum). , sputtering ion, kupopera mbewu mankhwalawa ndi njira zina) musanawombe ndi kupanga ma carbides ofanana nawo, kapena zitsulo zodzaza kwambiri zitha kugwiritsidwa ntchito.
Ma graphite ndi diamondi ali ndi magiredi ambiri, omwe amasiyana mu kukula kwa tinthu, kachulukidwe, chiyero ndi zina, ndipo amakhala ndi mawonekedwe osiyanasiyana.Komanso, ngati kutentha kwa polycrystalline diamondi zipangizo kuposa 1000 ℃, polycrystalline kuvala chiŵerengero akuyamba kuchepa, ndi kuvala chiŵerengero amachepetsa ndi oposa 50% pamene kutentha kuposa 1200 ℃.Choncho, pamene vakuyumu brazing diamondi, kutentha kwa brazing kuyenera kuyendetsedwa pansi pa 1200 ℃, ndi digiri ya vacuum idzakhala yosachepera 5 × 10-2Pa.
(2) Kusankhidwa kwachitsulo chodzaza ndi brazing kumatengera kugwiritsidwa ntchito ndi kukonza pamwamba.Ikagwiritsidwa ntchito ngati chinthu chosagwira kutentha, chitsulo chodzaza ndi brazing chokhala ndi kutentha kwambiri komanso kukana kutentha bwino chimasankhidwa;Pazinthu zolimbana ndi dzimbiri, zitsulo zodzaza ndi brazing zokhala ndi kutentha kochepa komanso kukana kwa dzimbiri zimasankhidwa.Pakuti graphite pambuyo pamwamba metallization mankhwala, koyera mkuwa solder ndi ductility mkulu ndi zabwino dzimbiri kukana angagwiritsidwe ntchito.Silver based and copper based active solder ali ndi wettability wabwino komanso fluidity ku graphite ndi diamondi, koma kutentha kwautumiki wolumikizana ndi brazed ndikovuta kupitilira 400 ℃.Pazigawo za graphite ndi zida za diamondi zomwe zimagwiritsidwa ntchito pakati pa 400 ℃ ndi 800 ℃, maziko agolide, maziko a palladium, maziko a manganese kapena zitsulo za titanium base filler nthawi zambiri amagwiritsidwa ntchito.Pamalo olumikizira omwe amagwiritsidwa ntchito pakati pa 800 ℃ ndi 1000 ℃, zitsulo zopangidwa ndi nickel kapena kubowola ziyenera kugwiritsidwa ntchito.Zida za graphite zikagwiritsidwa ntchito pamwamba pa 1000 ℃, zitsulo zodzaza zitsulo (Ni, PD, Ti) kapena zitsulo zodzaza ndi molybdenum, Mo, Ta ndi zinthu zina zomwe zimatha kupanga ma carbides okhala ndi kaboni zingagwiritsidwe ntchito.
Kwa graphite kapena diamondi popanda chithandizo chapamwamba, zitsulo zodzaza zomwe zili patebulo 16 zitha kugwiritsidwa ntchito pakuwomba mwachindunji.Zambiri mwazitsulo zodzaza ndi titaniyamu zochokera ku binary kapena ternary alloys.Titaniyamu yoyera imakhudzidwa kwambiri ndi graphite, yomwe imatha kupanga wosanjikiza kwambiri wa carbide, ndipo kukula kwake kofananira ndi kosiyana kwambiri ndi graphite, yomwe ndi yosavuta kutulutsa ming'alu, chifukwa chake singagwiritsidwe ntchito ngati solder.Kuphatikiza kwa Cr ndi Ni to Ti kumatha kuchepetsa malo osungunuka ndikuwongolera kunyowa ndi zoumba.Ti ndi ternary alloy, makamaka wopangidwa ndi Ti Zr, ndi kuwonjezera kwa TA, Nb ndi zinthu zina.Ili ndi coefficient yotsika ya kukula kwa mzere, zomwe zingachepetse kupsinjika kwa brazing.The ternary alloy makamaka yopangidwa ndi Ti Cu ndiyoyenera kuyikapo graphite ndi chitsulo, ndipo cholumikiziracho chimakhala ndi kukana kwa dzimbiri.
Table 16 brazing filler zitsulo zopangira mwachindunji ma graphite ndi diamondi
(3) Kuwotcha njira njira zowotcha za graphite zingagawidwe m'magulu awiri, imodzi ndi brazing pambuyo pazitsulo zachitsulo, ndipo ina ikuwomba popanda mankhwala.Ziribe kanthu kuti ndi njira iti yomwe ikugwiritsidwa ntchito, kuwotchererako kumayenera kukonzedwa musanasonkhene, ndipo zonyansa zamtundu wa graphite zidzapukutidwa ndi mowa kapena acetone.Pankhani yazitsulo zachitsulo pamwamba, Ni, Cu kapena wosanjikiza wa Ti, Zr kapena molybdenum disilicide adzakutidwa pamwamba pa graphite ndi kupopera mbewu mankhwalawa ndi plasma, ndiyeno zitsulo zamkuwa kapena zitsulo zopangidwa ndi siliva zidzagwiritsidwa ntchito pakuwotcha. .Kuwotcha molunjika ndi solder yogwira ndiyo njira yomwe imagwiritsidwa ntchito kwambiri pakali pano.Kutentha kwachitsulo kumatha kusankhidwa molingana ndi solder yoperekedwa mu tebulo 16. Solder ikhoza kumangirizidwa pakati pa mgwirizano wonyezimira kapena pafupi ndi mapeto amodzi.Mukawotcha ndi chitsulo chokhala ndi mphamvu yayikulu yowonjezera kutentha, Mo kapena Ti yokhala ndi makulidwe ena atha kugwiritsidwa ntchito ngati gawo lapakati.Zosanjikiza zosinthika zimatha kutulutsa pulasitiki pakuwotcha moto, kuyamwa kupsinjika kwamafuta ndikupewa kusweka kwa graphite.Mwachitsanzo, Mo imagwiritsidwa ntchito ngati cholumikizira cholumikizira cha vacuum brazing ya graphite ndi zida za hastelloyn.B-pd60ni35cr5 solder yokhala ndi kukana bwino kwa dzimbiri la mchere wosungunuka ndi ma radiation amagwiritsidwa ntchito.Kutentha kwa brazing ndi 1260 ℃ ndipo kutentha kumasungidwa kwa 10min.
Daimondi yachilengedwe imatha kulumikizidwa mwachindunji ndi b-ag68.8cu16.7ti4.5, b-ag66cu26ti8 ndi ma solders ena ogwira ntchito.Kuwotcha kuyenera kuchitika pansi pa vacuum kapena chitetezo chochepa cha argon.Kutentha kwa brazing sikuyenera kupitirira 850 ℃, ndipo kutentha kwachangu kuyenera kusankhidwa.Nthawi yogwira pa kutentha kwa brazing sikuyenera kukhala yaitali kwambiri (kawirikawiri pafupifupi 10s) kuti tipewe mapangidwe a tic wosanjikiza pa mawonekedwe.Mukawotcha diamondi ndi aloyi chitsulo, pulasitiki interlayer kapena low expansion alloy layer iyenera kuwonjezeredwa kuti musinthe kuti mupewe kuwonongeka kwa njere za diamondi chifukwa cha kupsinjika kwambiri kwamafuta.Chida chotembenuza kapena chida chotopetsa cha makina opangira ma ultra-precision machining chimapangidwa ndi njira yowotcha, yomwe imatulutsa 20 ~ 100mg tinthu tating'ono ta diamondi pathupi lachitsulo, ndipo mphamvu yolumikizirana yolumikizira imafika 200 ~ 250mpa.
Daimondi ya polycrystalline imatha kuwongoleredwa ndi lawi lamoto, ma frequency apamwamba kapena vacuum.Kuwotcha pafupipafupi kwambiri kapena kuyatsa moto kumatengedwa ngati chitsulo chozungulira chozungulira cha diamondi kapena mwala.Ag Cu Ti yogwira ntchito brazing filler zitsulo ndi malo otsika osungunuka adzasankhidwa.Kutentha kwa brazing kumayendetsedwa pansi pa 850 ℃, nthawi yotentha sikhala yayitali kwambiri, ndipo kuzizira pang'onopang'ono kumakhazikitsidwa.Zidutswa za diamondi za polycrystalline zomwe zimagwiritsidwa ntchito pobowola mafuta ndi geological sizigwira ntchito bwino ndipo zimanyamula katundu wambiri.Chitsulo chodzaza ndi nickel chimatha kusankhidwa ndipo zojambulazo zoyera zamkuwa zitha kugwiritsidwa ntchito ngati cholumikizira cha vacuum brazing.Mwachitsanzo, 350 ~ 400 makapisozi Ф 4.5 ~ 4.5mm columnar polycrystalline diamondi ndi brazed mu perforations 35CrMo kapena 40CrNiMo zitsulo kupanga kudula mano.Vacuum brazing imatengedwa, ndipo digiri ya vacuum imakhala yosachepera 5 × 10-2Pa, kutentha kwamoto ndi 1020 ± 5 ℃, nthawi yogwira ndi 20 ± 2min, ndipo mphamvu yakumeta ubweya wa mgwirizano wowotcha ndi wamkulu kuposa 200mpa.
Panthawi yowotcha, kulemera kwake kwa kuwotcherera kudzagwiritsidwa ntchito posonkhanitsa ndi kuikapo momwe zingathere kuti gawo lachitsulo lisindikize graphite kapena polycrystalline zinthu kumtunda.Mukamagwiritsa ntchito choyikapo poyikirapo, zida zomangira zizikhala zakuthupi zomwe zimakhala ndi coefficient yowonjezera kutentha yofanana ndi ya weldment.
Nthawi yotumiza: Jun-13-2022