(1) Izici ze-Brazing izinkinga ezihilelekile ku-graphite kanye ne-diamond polycrystalline brazing zifana kakhulu nalezo ezitholakala ku-ceramic brazing. Uma kuqhathaniswa nensimbi, i-solder kunzima ukumanzisa izinto ze-graphite kanye ne-diamond polycrystalline, futhi i-coefficient yayo yokwanda kokushisa ihluke kakhulu kweyezinto zokwakha ezijwayelekile. Zombili zifudunyezwa ngqo emoyeni, futhi i-oxidation noma i-carbonization izokwenzeka lapho izinga lokushisa lidlula u-400 ℃. Ngakho-ke, i-vacuum brazing kufanele isetshenziswe, futhi izinga le-vacuum akufanele libe ngaphansi kuka-10-1pa. Ngenxa yokuthi amandla azo zombili awaphezulu, uma kukhona ukucindezeleka kokushisa ngesikhathi se-brazing, kungase kube nemifantu. Zama ukukhetha insimbi ye-brazing filler ene-coefficient ephansi yokwanda kokushisa futhi ulawule ngokuqinile izinga lokupholisa. Njengoba ubuso bezinto ezinjalo bungelula ukumanziswa yizinsimbi ezivamile zokugcwalisa i-brazing, ungqimba lwe-W, i-Mo kanye nezinye izakhi ezingama-2.5 ~ 12.5um ubukhulu lungafakwa ebusweni bezinto ze-graphite ne-diamond polycrystalline ngokuguqulwa kwendawo (i-vacuum coating, i-ion sputtering, i-plasma spray nezinye izindlela) ngaphambi kokufaka i-brazing bese kwakha ama-carbide ahambisana nawo, noma kungasetshenziswa izinsimbi zokugcwalisa i-brazing ezisebenza kakhulu.
I-Graphite nedayimane zinamabanga amaningi, ahluke ngobukhulu bezinhlayiya, ubuningi, ubumsulwa nezinye izici, futhi zinezici ezahlukene zokubhebhezela. Ngaphezu kwalokho, uma izinga lokushisa lezinto zedayimane ze-polycrystalline lidlula i-1000 ℃, isilinganiso sokugqokwa kwe-polycrystalline siqala ukwehla, futhi isilinganiso sokugqokwa sincipha ngaphezu kwama-50% uma izinga lokushisa lidlula i-1200 ℃. Ngakho-ke, lapho kubhebhezela idayimane nge-vacuum brazing, izinga lokushisa lokubhebhezela kumele lilawulwe ngaphansi kwe-1200 ℃, futhi izinga lokubhebhezela akufanele libe ngaphansi kwe-5 × 10-2Pa.
(2) Ukukhetha insimbi yokugcwalisa i-brazing kusekelwe kakhulu ekusetshenzisweni nasekucutshungulweni kwendawo. Uma isetshenziswa njengento engamelani nokushisa, insimbi yokugcwalisa i-brazing enezinga lokushisa eliphezulu le-brazing kanye nokumelana okuhle nokushisa kufanele ikhethwe; Ukuze uthole izinto ezingamelani nokugqwala ngamakhemikhali, kukhethwa izinsimbi zokugcwalisa i-brazing ezinezinga lokushisa eliphansi le-brazing kanye nokumelana okuhle nokugqwala. Ukuze uthole i-graphite ngemva kokwelashwa kwe-surface metallization, i-solder yethusi emsulwa ene-ductility ephezulu kanye nokumelana okuhle nokugqwala ingasetshenziswa. I-solder esebenzayo esekelwe esiliva kanye nethusi inokumanzisa okuhle kanye nokugeleza kwe-graphite nedayimane, kodwa izinga lokushisa lenkonzo ye-brazed joint kunzima ukudlula u-400 ℃. Ukuze uthole izingxenye ze-graphite namathuluzi edayimane asetshenziswa phakathi kuka-400 ℃ no-800 ℃, isisekelo segolide, isisekelo se-palladium, isisekelo se-manganese noma isisekelo se-titanium ngokuvamile kusetshenziswa. Ukuze uthole amalunga asetshenziswa phakathi kuka-800 ℃ no-1000 ℃, kufanele kusetshenziswe izinsimbi zokugcwalisa ezisekelwe ku-nickel noma ze-drill. Uma kusetshenziswa izingxenye ze-graphite ezingaphezu kuka-1000 ℃, izinsimbi zokugcwalisa insimbi ezihlanzekile (i-Ni, i-PD, i-Ti) noma izinsimbi zokugcwalisa i-alloy eziqukethe i-molybdenum, i-Mo, i-Ta nezinye izinto ezingakha ama-carbide nge-carbon zingasetshenziswa.
Ku-graphite noma idayimane ngaphandle kokwelashwa kwendawo, izinsimbi zokugcwalisa ezisebenzayo kuthebula 16 zingasetshenziswa ekubhebheni okuqondile. Iningi lalezi zinsimbi zokugcwalisa ziyi-alloy ezimbili noma ezintathu ezisekelwe ku-titanium. I-titanium emsulwa isabela kakhulu nge-graphite, engakha ungqimba lwe-carbide olujiyile kakhulu, futhi i-coefficient yayo yokwandisa eqondile ihluke kakhulu kweye-graphite, okulula ukuyikhipha, ngakho-ke ayikwazi ukusetshenziswa njenge-solder. Ukwengezwa kwe-Cr ne-Ni ku-Ti kunganciphisa iphuzu lokuncibilika futhi kuthuthukise ukumanzi nge-ceramics. I-Ti iyi-alloy ye-ternary, eyakhiwe kakhulu yi-Ti Zr, ngokufakwa kwe-TA, i-Nb nezinye izinto. Ine-coefficient ephansi yokwandisa eqondile, enganciphisa ukucindezeleka kokubhebheni. I-alloy ye-ternary eyakhiwe kakhulu yi-Ti Cu ifanelekela ukubhebheni kwe-graphite nensimbi, futhi i-joint inokumelana okuphezulu kokugqwala.
Ithebula 16 izinsimbi zokugcwalisa i-brazing zokufaka i-graphite nedayimane ngqo
(3) Inqubo ye-brazing, izindlela ze-brazing ze-graphite zingahlukaniswa ngezigaba ezimbili, enye i-brazing ngemva kwe-surface metallization, kanti enye i-brazing ngaphandle kokwelashwa kobuso. Kungakhathaliseki ukuthi iyiphi indlela esetshenziswayo, i-weldment kufanele ilungiswe kusengaphambili ngaphambi kokuhlanganiswa, futhi ukungcola kobuso bezinto ze-graphite kufanele kusulwe ngotshwala noma i-acetone. Uma kwenzeka i-surface metallization brazing, ungqimba lwe-Ni, Cu noma ungqimba lwe-Ti, Zr noma i-molybdenum disilicide kufanele lufakwe phezu kobuso be-graphite ngokufafaza nge-plasma, bese kusetshenziselwa insimbi ye-filler esekelwe ethusi noma insimbi yesiliva ukuze kufakwe i-brazing. I-Direct brazing ene-active solder iyindlela esetshenziswa kakhulu njengamanje. Izinga lokushisa le-brazing lingakhethwa ngokuya nge-solder enikezwe kuthebula 16. I-solder ingafakwa phakathi kwe-brazed joint noma eduze kokuphela komunye. Lapho i-brazing ngensimbi ene-coefficient enkulu yokwanda kokushisa, i-Mo noma i-Ti enobukhulu obuthile ingasetshenziswa njengengqimba ye-buffer ephakathi. Isendlalelo soguquko singadala ukuguqulwa kwepulasitiki ngesikhathi sokushisa kwe-brazing, simunce ukucindezeleka kokushisa futhi sigweme ukuqhekeka kwe-graphite. Isibonelo, i-Mo isetshenziswa njenge-transition joint ye-vacuum brazing yezingxenye ze-graphite ne-hastelloyn. I-solder ye-B-pd60ni35cr5 enokumelana okuhle nokugqwala kosawoti oncibilikisiwe kanye nemisebe iyasetshenziswa. Izinga lokushisa le-brazing lingu-1260 ℃ futhi izinga lokushisa ligcinwa imizuzu eyi-10.
Idayimani yemvelo ingafakwa ngqo nge-b-ag68.8cu16.7ti4.5, b-ag66cu26ti8 kanye nezinye izihlanganisi ezisebenzayo. I-brazing kufanele yenziwe ngaphansi kokuvikelwa kwe-vacuum noma i-argon ephansi. Izinga lokushisa le-brazing akufanele lidlule ku-850 ℃, futhi kufanele kukhethwe izinga lokushisa elisheshayo. Isikhathi sokubamba ekushiseni kwe-brazing akufanele sibe side kakhulu (ngokuvamile cishe amasekhondi ayi-10) ukuze kugwenywe ukwakheka kwesendlalelo se-tic esiqhubekayo esibonakalayo. Lapho kufakwa idayimani nensimbi ye-alloy, kufanele kwengezwe isendlalelo sepulasitiki noma isendlalelo se-alloy esiphansi ukuze kuguqulwe ukuvimbela umonakalo wezinhlayiya zedayimani ezibangelwa ukucindezeleka okukhulu kokushisa. Ithuluzi lokujika noma ithuluzi eliyisicefe lomshini wokulungisa ngokunemba okukhulu lenziwa ngenqubo ye-brazing, efaka idayimani elincane elingu-20 ~ 100mg emzimbeni wensimbi, futhi amandla ahlangene ejoyinti le-brazing afinyelela ku-200 ~ 250mpa
Idayimani ye-polycrystalline ingashiswa nge-brazing ngelangabi, i-frequency ephezulu noma i-vacuum. I-brazing ephezulu noma i-flame brazing kufanele isetshenziswe ensimbini yokusika i-blade yedayimani eyindilinga noma itshe. Insimbi yokugcwalisa i-brazing esebenzayo ye-Ag Cu Ti enephuzu eliphansi lokuncibilika kufanele ikhethwe. Izinga lokushisa le-brazing kufanele lilawulwe ngaphansi kuka-850 ℃, isikhathi sokushisa akufanele sibe side kakhulu, futhi izinga lokupholisa elihamba kancane kufanele lisetshenziswe. Ama-diamond bits e-polycrystalline asetshenziswa ekubholeni nge-petroleum kanye ne-geological anezimo zokusebenza ezimbi futhi athwala imithwalo emikhulu yomthelela. Insimbi yokugcwalisa i-brazing esekelwe ku-nickel ingakhethwa futhi i-foil yethusi emsulwa ingasetshenziswa njengengqimba yokuhlanganisa i-vacuum brazing. Isibonelo, ama-capsule angu-350 ~ 400 Ф 4.5 ~ 4.5mm columnar polycrystalline diamond ishiswa nge-brazing ema-perforations ensimbi engu-35CrMo noma engu-40CrNiMo ukuze kwakheke amazinyo okusika. Ukushiswa kwe-vacuum brazing kuyamukelwa, futhi izinga lokushiswa kwe-vacuum alingaphansi kuka-5 × 10-2Pa, izinga lokushisa lokushiswa kwe-brazing lingu-1020 ± 5 ℃, isikhathi sokubamba singama-20 ± 2min, futhi amandla okusika ejoyinti lokushiswa kwe-brazing makhulu kuno-200mpa.
Ngesikhathi sokubilisa, isisindo somshini wokushisela kufanele sisetshenziswe ekuhlanganiseni nasekubekeni indawo ngangokunokwenzeka ukuze ingxenye yensimbi icindezele i-graphite noma i-polycrystalline material engxenyeni engenhla. Uma usebenzisa umshini wokushisela indawo, umshini wokushisela kufanele ube yi-material ene-thermal expansion coefficient efana neye-weldment.
Isikhathi sokuthunyelwe: Juni-13-2022