(1) Cov yam ntxwv ntawm kev sib txhuam cov teeb meem uas cuam tshuam nrog graphite thiab pob zeb diamond polycrystalline brazing zoo ib yam li cov uas ntsib hauv kev sib txhuam ceramic. Piv nrog hlau, solder nyuaj rau ntub graphite thiab pob zeb diamond polycrystalline cov ntaub ntawv, thiab nws cov coefficient ntawm thermal expansion txawv ntawm cov ntaub ntawv dav dav. Ob qho tib si raug cua sov ncaj qha hauv huab cua, thiab oxidation lossis carbonization yuav tshwm sim thaum qhov kub tshaj 400 ℃. Yog li ntawd, yuav tsum tau siv lub tshuab nqus tsev brazing, thiab qib nqus tsev yuav tsum tsis pub tsawg dua 10-1pa. Vim tias lub zog ntawm ob qho tib si tsis siab, yog tias muaj kev ntxhov siab thermal thaum lub sijhawm brazing, tej zaum yuav muaj kab nrib pleb. Sim xaiv cov hlau brazing filler nrog cov coefficient qis ntawm thermal expansion thiab tswj hwm tus nqi txias. Vim tias qhov chaw ntawm cov ntaub ntawv zoo li no tsis yooj yim rau ntub los ntawm cov hlau nplaum brazing, ib txheej ntawm 2.5 ~ 12.5um tuab W, Mo thiab lwm yam khoom tuaj yeem tso rau ntawm qhov chaw ntawm graphite thiab pob zeb diamond polycrystalline cov ntaub ntawv los ntawm kev hloov kho qhov chaw (txheej nqus tsev, ion sputtering, plasma spraying thiab lwm txoj kev) ua ntej brazing thiab tsim cov carbides sib xws nrog lawv, lossis cov hlau nplaum brazing ua haujlwm siab tuaj yeem siv.
Graphite thiab pob zeb diamond muaj ntau qib, uas sib txawv ntawm qhov loj me ntawm cov khoom me me, qhov ceev, kev huv thiab lwm yam, thiab muaj cov yam ntxwv sib txawv ntawm kev sib txhuam. Tsis tas li ntawd, yog tias qhov kub ntawm cov pob zeb diamond polycrystalline tshaj 1000 ℃, qhov piv ntawm kev hnav polycrystalline pib txo qis, thiab qhov piv ntawm kev hnav txo qis ntau dua 50% thaum qhov kub tshaj 1200 ℃. Yog li ntawd, thaum lub tshuab nqus tsev brazing pob zeb diamond, qhov kub brazing yuav tsum tau tswj hwm qis dua 1200 ℃, thiab qib nqus tsev yuav tsum tsis pub tsawg dua 5 × 10-2Pa.
(2) Kev xaiv cov hlau nplaum yog raws li kev siv thiab kev ua tiav ntawm qhov chaw. Thaum siv ua cov khoom siv tiv taus kub, yuav tsum xaiv cov hlau nplaum uas muaj qhov kub siab thiab tiv taus kub zoo; Rau cov khoom siv tiv taus tshuaj lom neeg, yuav tsum xaiv cov hlau nplaum uas muaj qhov kub qis thiab tiv taus corrosion zoo. Rau cov graphite tom qab kho cov hlau nplaum saum npoo, yuav siv cov hlau nplaum tooj liab ntshiab uas muaj ductility siab thiab tiv taus corrosion zoo. Cov hlau nplaum nyiaj thiab tooj liab muaj qhov ntub thiab fluidity zoo rau graphite thiab pob zeb diamond, tab sis qhov kub ntawm cov hlau nplaum nyuaj rau tshaj 400 ℃. Rau cov khoom siv graphite thiab cov cuab yeej pob zeb diamond siv ntawm 400 ℃ thiab 800 ℃, feem ntau siv cov hlau nplaum kub, palladium, manganese lossis titanium. Rau cov pob qij txha siv ntawm 800 ℃ thiab 1000 ℃, yuav tsum siv cov hlau nplaum nickel lossis laum. Thaum cov khoom siv graphite siv siab tshaj 1000 ℃, cov hlau ntshiab (Ni, PD, Ti) lossis cov hlau sib xyaw uas muaj molybdenum, Mo, Ta thiab lwm yam khoom uas tuaj yeem tsim cov carbides nrog carbon tuaj yeem siv tau.
Rau graphite lossis pob zeb diamond uas tsis muaj kev kho saum npoo, cov hlau ua kom nquag hauv lub rooj 16 tuaj yeem siv rau kev sib txhuam ncaj qha. Feem ntau ntawm cov hlau ua kom nquag no yog titanium raws li binary lossis ternary alloys. Titanium ntshiab reacts muaj zog nrog graphite, uas tuaj yeem tsim cov txheej carbide tuab heev, thiab nws cov coefficient nthuav dav linear yog txawv ntawm graphite, uas yooj yim tsim cov kab nrib pleb, yog li nws tsis tuaj yeem siv ua solder. Kev ntxiv Cr thiab Ni rau Ti tuaj yeem txo qhov melting point thiab txhim kho qhov wettability nrog ceramics. Ti yog ib qho ternary alloy, feem ntau yog tsim los ntawm Ti Zr, nrog rau kev ntxiv ntawm TA, Nb thiab lwm yam ntsiab lus. Nws muaj cov coefficient qis ntawm linear nthuav dav, uas tuaj yeem txo qhov kev ntxhov siab brazing. Lub ternary alloy feem ntau yog tsim los ntawm Ti Cu yog tsim rau kev sib txhuam ntawm graphite thiab hlau, thiab qhov sib koom ua ke muaj kev tiv thaiv corrosion siab.
Rooj 16 brazing filler hlau rau kev ncaj qha brazing ntawm graphite thiab pob zeb diamond
(3) Cov txheej txheem brazing Cov txheej txheem brazing ntawm graphite tuaj yeem muab faib ua ob pawg, ib qho yog brazing tom qab metallization ntawm qhov chaw, thiab lwm qhov yog brazing yam tsis muaj kev kho saum npoo. Txawm siv txoj kev twg los xij, qhov weldment yuav tsum tau pretreated ua ntej sib dhos, thiab cov khoom siv graphite yuav tsum tau so kom huv nrog cawv lossis acetone. Yog tias muaj metallization ntawm qhov chaw brazing, ib txheej ntawm Ni, Cu lossis ib txheej ntawm Ti, Zr lossis molybdenum disilicide yuav tsum tau plated rau ntawm qhov chaw graphite los ntawm plasma spraying, thiab tom qab ntawd tooj liab raws li filler hlau lossis nyiaj raws li filler hlau yuav tsum tau siv rau brazing. Brazing ncaj qha nrog active solder yog txoj kev siv dav tshaj plaws tam sim no. Qhov kub brazing tuaj yeem xaiv raws li solder muab rau hauv lub rooj 16. Lub solder tuaj yeem clamped hauv nruab nrab ntawm qhov sib koom ua ke brazed lossis ze ib kawg. Thaum brazing nrog hlau nrog cov coefficient loj ntawm thermal expansion, Mo lossis Ti nrog qee qhov tuab tuaj yeem siv ua txheej nruab nrab buffer. Cov txheej hloov pauv tuaj yeem tsim cov yas deformation thaum lub sijhawm brazing cua sov, nqus cov thermal kev ntxhov siab thiab zam graphite tawg. Piv txwv li, Mo yog siv ua qhov sib txuas hloov pauv rau kev siv lub tshuab nqus tsev rau graphite thiab hastelloyn. B-pd60ni35cr5 solder uas tiv taus cov ntsev molten corrosion thiab hluav taws xob zoo siv. Qhov kub ntawm brazing yog 1260 ℃ thiab qhov kub khaws cia rau 10 feeb.
Pob zeb diamond ntuj tuaj yeem ncaj qha brazed nrog b-ag68.8cu16.7ti4.5, b-ag66cu26ti8 thiab lwm yam solders nquag. Lub brazing yuav tsum tau ua nyob rau hauv lub tshuab nqus tsev lossis qis argon tiv thaiv. Lub kub brazing yuav tsum tsis pub tshaj 850 ℃, thiab qhov ceev cua sov yuav tsum tau xaiv. Lub sijhawm tuav ntawm qhov kub brazing yuav tsum tsis txhob ntev dhau (feem ntau yog li 10s) kom tsis txhob muaj kev tsim ntawm ib txheej tic tas mus li ntawm qhov interface. Thaum brazing pob zeb diamond thiab hlau alloy, yas interlayer lossis qis expansion alloy txheej yuav tsum tau ntxiv rau kev hloov pauv kom tiv thaiv kev puas tsuaj ntawm cov pob zeb diamond los ntawm kev ntxhov siab thermal ntau dhau. Lub cuab yeej tig lossis lub cuab yeej tho rau ultra precision machining yog tsim los ntawm cov txheej txheem brazing, uas brazes 20 ~ 100mg me me pob zeb diamond rau ntawm lub cev hlau, thiab lub zog sib koom ua ke ntawm lub brazing sib koom ua ke ncav cuag 200 ~ 250mpa
Pob zeb diamond polycrystalline tuaj yeem raug brazed los ntawm nplaim taws, zaus siab lossis lub tshuab nqus tsev. Yuav tsum tau siv brazing zaus siab lossis nplaim taws brazing rau pob zeb diamond pom hniav txiav hlau lossis pob zeb. Yuav tsum xaiv Ag Cu Ti active brazing filler hlau nrog qhov chaw yaj qis. Yuav tsum tswj qhov kub brazing hauv qab 850 ℃, lub sijhawm cua sov yuav tsum tsis txhob ntev dhau, thiab yuav tsum siv qhov txias qeeb. Cov pob zeb diamond polycrystalline siv hauv roj av thiab geological drilling muaj cov xwm txheej ua haujlwm tsis zoo thiab dais cov khoom hnyav. Nickel raws li brazing filler hlau tuaj yeem xaiv tau thiab cov ntawv ci tooj liab ntshiab tuaj yeem siv ua interlayer rau brazing nqus tsev. Piv txwv li, 350 ~ 400 capsules Ф 4.5 ~ 4.5mm columnar polycrystalline diamond yog brazed rau hauv cov perforations ntawm 35CrMo lossis 40CrNiMo hlau los tsim cov hniav txiav. Siv lub tshuab nqus tsev brazing, thiab qib nqus tsev tsis tsawg dua 5 × 10-2Pa, qhov kub brazing yog 1020 ± 5 ℃, lub sijhawm tuav yog 20 ± 2 feeb, thiab lub zog shear ntawm qhov sib koom ua ke yog ntau dua 200mpa
Thaum lub sijhawm vuam, qhov hnyav ntawm qhov vuam yuav tsum tau siv rau kev sib dhos thiab kev teeb tsa kom ntau li ntau tau kom cov hlau nias cov khoom siv graphite lossis polycrystalline ntawm sab saud. Thaum siv lub cuab yeej rau kev teeb tsa, cov khoom siv kho yuav tsum yog cov khoom siv nrog cov coefficient thermal expansion zoo ib yam li ntawm qhov vuam.
Lub sijhawm tshaj tawm: Lub Rau Hli-13-2022