Ukufundwa Kwempilo Yoxhasa KwiVacuum Brazing Enye NgeBhotile

Kutheni Ukuxhasa Kuthintela Ubunzima Bomthwalo WeDiamond Ngexesha Lokusinta

Ukuxhaswa kwe-oksijini kusenza kube khethiwe kwiindlela ezibopheleyo phakathi kwemithombo ngokuxhaswa kwe-vacuum, okunokuthatha indawo yobudlelane phakathi kwe-diamonds nezinto ezinezinkunkuma ngama-34 phakathi kuka-ASM International esekelwe kwindaba yekhono yekhono ephakathi kuka-2022. Njengoko kubonakala, izinto ezincinci zokshisayo, njenge-0.01% kwi-athmosifiri, ziyakhothazela ukuxhaswa kwe-chromium oxide kwiindlela ezipheleleyo ezinezinkunkuma. Lokhu kwenza isixhobo phakathi kwe-diamonds nezinkunkuma zazo zibe yinyani engaphantsi xa isixhobo sisetshenziswa. Inkohlakalo iyaphucula ngoba lo xhobo lwexhaswa kwenza kube yinyani ukuguqulwa kwe-diamonds kwi-graphite. Iintsango ezimbalwa zafumana ukuthi ukuguqulwa kwe-carbon kuya ngokukhawuleza kuma-15% xa kukho okungahlekile kwi-oksijini, njengoko kuchazwe kwi-Journal ye-Materials Processing Technology ngo-2022. Kumaqhawe asebenzisa izixhobo ze-diamond, ukulawula loo ngxaki yexhaswa kusenokwenzeka kubaluleke kakhulu ukugcina ubume bezixhobo nezisemgangathweni zazo ngexesha elide.

Indima Yokugcinwa Kwe-Oxygen Partial Pressure ekuhlanukeni kwe-Metal-Diamond Interfacial

Ukuxheleneyo phakathi kwe-oxygen activity nentona evakuvenkile kumithuthi yovacuum kuyafihla into esithiwa yi-Arrhenius pattern, lapho amanzi we-oxygen ayadonsela kabili ngalinye i-55 degree Celsius ukunyuka kwentona. Xa kusebenziswa ngemini ye-900 degrees Celsius ngduring sintering processes, amanzi amancane kakhulu we-oxygen - njengoba ngu-0.0001 millibar kuphela - angethula ekwakhiweni kwe-chromium oxide emakhelwini we-braze. Lokhu kunika iziphumo eziningi kumathuba okugcina kwe-diamond, okwenzeka kuyahlukanisa ngaphakathi kuka-20% kuze kube ngu-40%, ngokwesicwangciso esaphublikisha ku-Materials Science and Engineering ngo-2021. Kuyazekelwa, manje amathuba avumelekile asevacuuma ayehlala ekulungiseni lo mphango. Ayehlala ekulandelela izinkinga ze-partial pressures ngokusheshayo, ayagcina lezi zinkinga ze-oxygen ngezansi kwezinkinga eziphathelene ne-0.00005 millibar kuzo zonke izindawo zomgwa wokuthinta.

Isifundo Sombhalo: Ukudala Kwesikhwama sika-Cr kanye Nokulahlekwa Kweqhando ezi Qaqawini zeNi-Cr ezingaphandle kuka-900°C

Umhlaziyalo otholakeleyo wenzeke nge alloy yeNiCr-7 yeqhando libonisa ukuthi ukuthutha kwesikhwama sikasikhwama kubangelwa ngokuphindaphindiwe kwesigaba:

Ububanzi besikhwama	Ukugcina Kwezinkinga Zesiphumo	Ishedi Lekhipha Le-Diamond
0.5 µm	92%	8%
2.1 µm	66%	27%
4.3 µm	41%	52%

Amasampula etholakala ngaphezu kuka-2 µm yesikhwama sabonakala yokulahlekwa kaburhamu kweqhando ngaphakathi kwezikhathi ezingu-50. Ngokumelene, izigaba ezitholakalayo emanzini ephelele entsimbeni (<10^2 µmbar) zazigcina izinkinga zazo ezingu-98% emva kwezikhathi ezingu-200 (IWTO Conference Proceedings 2023), lokhu kubonisa ukuthi kudingeka kube khona ukulawula okukhokwelelayo kwebhubhesi ezigaba zabubi ezenza izixhumanisi zezindiza zezidolobha.

Ukulungiselela Umoya We-Vacuum Ukuze Kuhlulwe I-Bhubhesi

Ukuphatha izigasi ezisezulwini kanye nezifunyanwa kumzimba wokugquba izigasi

Noma kunjalo izigasi zokwephula ezingaphansi kuka-20 kwezinguquko ezingu-1 ezingu-1 ezingu-1 zingakhiqiza iinkankazo ezikhulu xa idiamond iphinda igraphite ngexesha le-sintering. Lokhu kuthetha ukuba iibladi zilindela ngenxa ye-63% engaphantsi kwemeko yabo ngokomzekelo xa ii-oxide layers ziphumelela kancinci kune-micrometer ngelixa lika-IMR elisha kwi-2023. Ukulungiselela lo nkankozo, iivacuum furnaces zamanje zavelisa iindlela ezahlukene zokususa izigasi ezingathandakaliyo. Okokuqala, zihlanya iingcindezi ngaphezu kuka-450 degrees Celsius ngemva kwe-90 minutes ukuze zisuse izigasi ezithintekayo. Emva koko abawebhanga bamenza amandla okuhlenga afuthi apho akusayi kususa lutho (ngaphantsi kuka-0.05% volatiles ngubuningi). Ekugcineni, abasebenzisi bahlola iingcinga zezigasi ngokucophelela ngexesha lonke lwesiproso lokuhlanya ukuze bephile kumakhilibhedile aseleyo.

Fumanisa ivacuum enkulu (<10^2 µmbar) ukuze kuthintelwe iziphumo ezivavanyayo

Ngama-10^2 µmbar, indawo ephakathi kwezikhathi ziyakwazi i-10 km—kuyahlukisa ngokuphelele ukwakha kwe-oxidation. Izivikelo ezifundiswa kusho ukuthi kukhulunywa ngama-97% ekwakheni kwe-Cr₂O₃ uma lokhu kugcinwa ngokuthi kugcinwa lokhu kugcinwa kwi-750–900°C indawo ebalulekile yokwakha (2024 High-Temperature Processing Study).

Isilinganiso se-Vacuum (mbar)	Isikhathi se-Dwell (min)	Isilinganiso se-Oxidation (mg/cm²)
10³	30	0.42
10´	30	0.15
10²	30	0.03

Ukuthwala: Ukuhlelwa kwe-pump-down nokulawula kwe-leak-up rate ukuze kugcinwe ubumnandi bwe-oxygen

Izinhlelo zomshini wokuphazanyiswa ngokuqinile kungafinyelela imithuthuko engaphansi kwembar 10^-4 ngaphakathi kwezimini ezingu-18 ngokushesha. Umsebenzi kuqala ngokuvula iziphampheli ze-turbomolecular ezingaphezu kwembar 10^-2, usebenzisa izindlu zokugcina okulahlekayo eziphakeme kuzinkwa ngezinsuku ezingaphansi kuka-minus 140 degrees Celsius ukuze zilande amanzi, kanye nokulandela ukulahlekwa kusikelela ngexesha elifanayo ngezidingo ezingama-5x10^-6 mbar liters ngosihlwe. Ukudibanisa lezi ndlela kususa umkhawulo wokuxhaseka kwegesi ye-oxygen kabusha 80-85% kunazo ezintanga. Lokhu kuyinto eyodwa kumathuba athintekayo, ikakhulu lezi zi-alloy zezibhobho-njani eziphathekayo kuzibhobho-njani eziphathekayo apho kuphela ukuba kukhona isilinganiso esincane segesi ye-oxygen singayiphatha konke into.

Ukusebenzisa I-Atmospheres Zokukhuselela Ukuhlukaniswa

Ukukhuphuka Kwe-Hydrogen: Ukususa I-Oxides Zentonga Ngaphambi Kokubhoba

Amagazini e-Hydrogen ayisusa izikhumba ze-oxide kungaphezu kwezikhathi ezishiyagalombili(8×) kulokho okuphathelene kuphela. Phakathi kwezingu-750–850°C, i-hydrogen iyaphindaphindwa ne-chromium oxide (Cr₂O₃) emsulweni we-tool steel, wenza umlilo ophoqelekayo owisusiwa ngumshini wokususa igazi. Lendlela isusa izinhlayiya zezikhumba ku-0.2–0.5 µm/min ngemuva kokugcina ubukhuni be-diamond.

Ukusebenzisa izimunje ze-Argon-Hydrogen ukuze kuthuluzwe nokuthintelwe kabusha okwenzekayo

Imisebenzi yasebhakabhaka ihlala isebenzisa i-4–10% ye-hydrogen kumunje ka-argon ukulungiselela ukuphinda phinda nokulungile. Isimo se-argon sibandla ukuthuthana kwe-hydrogen, sivikela izimunje eziphambene ngokomthetho, njengoko kuyakhula amagazini e-oxygen ngezansi kwe-1×10¯ bar. Lokhu kumelela ukususwa kahle kwe-oxide kungama-15–30 minithi ngo-800°C—kungaphezu kwezikhathi ezine(40%) kunamagazini akhiwe kwi-nitrogen—ngaphandle kokuhlala kunezidingo zokuguquka kwesithelo se-diamond.

Ukulungiselela Ukuphinda phinda nokulungile kwe-Hydrogen-Assisted Vacuum Brazing

Imithombo yamanje ihlala isebenzisa imisebenzi yokulinganisa ngexesha eliqinileyo ukulungisa iingcinga ze-hydrogen kumkhawulo, ngokuvamile kumphindaphindo weshumi elinesibhozo kumathuba awo. Iintsontela zibonile ukuba ukudibanisa iingcinga eziphinda phinda 7 ze-hydrogen ne-argon kusebenza kangcono kakhulu ekufuneni ukufakelwa kwemithombo ye-braze, naphakade kubeka amagasi athembekayo apholakele kumthetho wokwehla kumgama ophinda phinda 35 wokuphendula kakhulu. Ekucingeni emva kokusebenzisa, inzululwana ezintathu zezixhobo zokuhlutha izishishini ezingaphantsi kumshwelo wesigidi esinyane kunye nomnyaka. Lo msebenzi omhle ususa iimolekyuli ezingalunganga ze-hydrogen kusistimu ukuze xa izinto zihamba kwiindlela, ziphume ngokuchanekileyo nezigaba eziphambene ne-ISO 15614 ezingafunyanwa ngabasebenzisi.

Ukukhokelela nokulawula Iziganeko Ezibalulekileyo ZeThermodynamic

Iinkcukacha Ze-Metal-Oxide: Ukuchazwa Kwizilingo Zokuxhasa Ngaphezu Kwemipunga Yophondo

Ukusebenzisa izinkomba zomlando wemetalloxide ukuze kuthunyelwe kumodeli yokusebenza kwenjini yenthalpy kusinika abayimfazwe indlela yokubhekisa izinkinga zokuthutha xa kusebenziswa imisebenzi yokudweba ngovacuum. Xa kusebenziwa ngokuthinta-nye nezilimi ze-Ni Cr B, lezi zinkomba zibonisa izinkinga ezibalulekile apho ikhrōmyimu kusasa kuthutha kakhulu uma izinkoka ziyaphinda ngaphezu kwe-800 degrees Celsius ngokwesicwangciso esiphubekayo eJournal of Thermal Analysis ngo-2022. Izinto zihlupha kakhulu ngemva kwe-900C uma izilinganiso zoksijini ngaphakathini kufinyelela kakhulu kune-1 times 10 to the minus 8 mbar, okusenza i-Cr2O3 ithutha kakhulu emibusweni lokhu kungumthwalo owodwa owahlupha izibhedele zomshini ngokwehla kwezinsuku. Ukudala lezi zimodeli zokubhekisa ngokuthunyelwe kudatha olutholakeleyo lwesivivinyo kusinika amathimba okuphatha izimo zokusebenza ngendlela esivikelwe kakhulu kuzinkinga zokuthutha okungcono.

Ukubeka isilinganiso sesikhathi sokudondoshisa njengendlela yokubala izilinganiso zoksijini ngaphakathi kwesivivinyo

Uma sibheka izindlela zomfutho ngezansi kwe-50 degrees Celsius, lezi zihlanganisa nezigaba zokcsanguca okuqukethwe kuqobo lwangaphakathi kwezimali ezingcolileyo ngokomlando ophublikisiwe ku-2023 International Journal of Refractory Metals. Ukufaka izikhali ze-infrared hygrometers emva kwephampheli yediffusion kuvumela ukuchazwa okuphindelelayo kwezimo, futhi uma izifinyezo ziqaqa qha, okwawukhona kungaba kukhona umlilo ohlala phakathi noma kunjalo nyongwa encane. Kubo bonke abasebenza nezindlela zokudweba, ukugcina izindlela zomfutho ngezansi kwe-60 degrees kwenza umehluko mkhulu. Izivikelo ezitholakele ku-Metals and Materials International zibanza lokhu ekubonisa ukuthi le zindlela ezincane zomfutho zicima izigaba zokcsanguca ezitholakalayo emkhatsini ngama-87% kokulinganiso ngenhla yezinto ezahlukene zokusebenzisa -40 degrees ngo-2021.

Ukuseta Amatheshiwoldi Asebenzisa (Indlela Yomfutho < -50°C) Ukulungiselela Kwakhiwa Kwe-Cr₂O₃

Xa kwenziwa ukubonakala kwemvelaphi, kubonakala ukuthi uma uhamba phezulu kwe-50 degrees Celsius dew point ngenkathi kubhaziywa phakathi kwe-850 kuya ku-920 degrees Celsius, lokhu kuthathazisa amaxesha athathu esivinini Cr2O3 ikhiqizwa ngaso ngokomlando wokulungiselela okwenzelwe ngo-Surface Engineering ngo-2021. Ukuthola leli qhingeza likhangelwa libathe izindiza ngaphandle kokuphula indawo efana nezimali eziphilayo zifuna ukusebenza kakhulu. Ukuqeqeshwa koko kunyaka emva kokuphumula okuniningi futhi kufanele kube ne-hydrogen purges ngemva kokuthi izinkukhu ziqaqa. Uma sifinyelela ngezansi kwe-55 degrees Celsius, kunjalo kunezinto ezilungileyo ezidlalwayo nezinhlangothi ze-nickel matrix, zibuyisela ngaphezu kwe-99 percent yezinkinga zabo ze-chromium. Loku kubaluleke kakhulu ngoba ukugcina leli xesha le-chromium likhangelwa libathe izinqamuzana eziqashelwayo zibe nemikhondo yokuhlaba uma izibhamu zakhiwa zisetshenziswa ukugcwalisa izinto ezizime.

Ukulungiselela Kwindawo Neqhikitho Lezemvelaphi Ngokuphepha Kwe-Oxidation

Izindlela Zokulungiselela Ukuvikelwa Kwemitholampofu Yezimanga Ngaphambi Koku-Brazing

Ukuphazamiseka ngaphambi kokudinwa kususa umsebenzi woximba phakathi nge-62% ikuselwa kumakhigijana angahleli (Inyange Yasekuhlaleni Kwesayensi 2024). Ukulungiswa ngaphosphate nokuchromate kwenza izigaba ezincane zomshini okugcina ukuthi kungabi khona ukuxhasa kusihlengalo, okubaluleke kakhulu ekwakhiweni kwamaphepha enqorha yokugaya yediamond esebenza kakhulu.

Ukusebenzisa Izingcingo Ezinezinkomo ZesiChromium Noma Izindlela Zokulungiswa Ngaphosphate Ukuze Kuthuthukiswe Ukuphazamisa

Izingcingo eziphinde zibonakala zesiChromium (ngaphansi kwe-5 µm) zibeka ububi bokuxhasa nge-40% e-900°C ngokudala kweCr₂O₃ okubangelwa. Izivikelo ezintsha zekhombisa ukuthi izinyangwana ezisekelwe kophosphate zinikeza ukuphazamisa okufanayo ngaphandle kweChromium enezinkinga, okuhlanganisa nezilawulo ezihlelekile ezigcinwa ngempilo yezimali ngokulungiswa kwesayensi.

Ukubeka Izinhlobo Zokushisa Ngendlela Efanayo Ukuze Kugcinwe Ukuguquka Kwesithili Somthombo WeDiamond Nokuxhasa Kwesikhala

Ukugcina izilinganiso zokuthutha phansi kwezingu-15 degrees Celsius ngomzuzu xa izinkukhu zilinda phansi kwezingu-700 zikusiza ukulungisa izidlalo ukukhathala kakhulu. Kodwa uma usaphumelela iphuzu lemelting yebhreysi, ukuthutha kungahlanjelwa kancane kunezingu-25 degrees ngomzuzu. Lokhu kususa ixesha elithile ekupheleni kwizinkinga zokuxhasa. Ngokwesiqiniseko esishicilelwe kuleminyaka edlule emazingeni mayelana nobuchwepheshe bezidlalo nge-vacuum, le ndlela ebonke kabili ibangela ukuncipha okungu-30% kwezidingo zokuguqulwa kwi-graphite futhi ikhuphula amafutha akho apholile ayingxenye yesandla ngaproximately 34%. Isiphumo? Izixhenxe ezineminyaka engaphezu nenganqalaba enempilo ehleli kangcono.

Imibuzo Emaninzi (FAQ)

Yini iyasiwekisweni ngokwemviko yokubuchwephesha nge-vacuum?

Ukuxhasa ngumvuko wokudala kwezindlela ze-oxide ezindaweni zezintshuku, okukhupha isibopho phakathi kwezinqamuzana, njengezidlalo nezintshuku ezisetshenziswa ekwenzeni izixhenxe.

Ukuxhasa kujikeleza kanjani izixhenxe zezidlalo?

Ukuxidwa kungakwazi ukuthi kuqaphe amadolo, kuyandisa ukudluliswa kwabo nezindlela, ngakho-ke kususa ubumfihlo nokusebenza kwezixhobo ngapha kwezinkinga.

Iziphi izikhala zokuphepha ekuqhakeleni?

Izikhala zokuphepha, njenge-hydrogen ne-argon blends, zisetyenziselwa ukunciphisa i-oxides zezinhlangothi kwaye ziphephe ukuxidwa ngexesha lokuhlanjwa, ngakho kuyavuthela ubume bezixhobo kwaye kube lula.

Ukuthi ixesha elibomvu likuthatha ntoni ekuxidweni?

Ukugcina ixesha elibomvu lingcono kunciphisa ukuxidwa ngokuncipha inani le-molecules ye-oxygen evela ukure akhokelele nezinhlangothi ze-metal ngexesha lezinkqubela ezityibilayo.

Iziphi iindlela zokuphepha kwakhona kwiqhotyoshelo le-diamond?

Iindlela zokuphepha zifaka ukulungiselela i-substrates ze-metal ukuze zenze amava ethuweyo aphulaphule ukuxidwa ngexesha lokuhlanjwa, ngoko kuyaphila ubumfihlo bezixhobo.