Kev sib txhuam ntawm cov hlau refractory

1. Siv cov khoom siv vuam

Txhua yam khoom siv solder uas kub qis dua 3000 ℃ siv tau rau W brazing, thiab cov khoom siv tooj liab lossis nyiaj siv tau rau cov khoom siv uas kub qis dua 400 ℃; Cov hlau kub, manganese, manganese, palladium lossis laum feem ntau siv rau cov khoom siv ntawm 400 ℃ thiab 900 ℃; Rau cov khoom siv siab dua 1000 ℃, cov hlau ntshiab xws li Nb, Ta, Ni, Pt, PD thiab Mo feem ntau siv. Qhov kub ua haujlwm ntawm cov khoom siv brazed nrog platinum base solder tau mus txog 2150 ℃. Yog tias 1080 ℃ diffusion kev kho mob tau ua tiav tom qab brazing, qhov kub ua haujlwm siab tshaj plaws tuaj yeem ncav cuag 3038 ℃.

Feem ntau ntawm cov solders siv rau brazing w tuaj yeem siv rau brazing Mo, thiab tooj liab lossis nyiaj solders tuaj yeem siv rau Mo Cheebtsam ua haujlwm hauv qab 400 ℃; Rau cov khoom siv hluav taws xob thiab cov khoom tsis yog cov qauv ua haujlwm ntawm 400 ~ 650 ℃, Cu Ag, Au Ni, PD Ni lossis Cu Ni solders tuaj yeem siv; Titanium raws li lossis lwm cov hlau ntshiab filler hlau nrog cov ntsiab lus melting siab tuaj yeem siv rau cov Cheebtsam ua haujlwm ntawm qhov kub siab dua. Nws yuav tsum tau sau tseg tias manganese raws li, cobalt raws li thiab nickel raws li filler hlau feem ntau tsis pom zoo kom tsis txhob muaj kev tsim ntawm brittle intermetallic compounds hauv brazing pob qij txha.

Thaum siv cov khoom TA lossis Nb hauv qab 1000 ℃, cov tooj liab, manganese, cobalt, titanium, nickel, kub thiab palladium tuaj yeem xaiv tau, suav nrog Cu Au, Au Ni, PD Ni thiab Pt Au_ Ni thiab Cu Sn solders muaj qhov zoo rau TA thiab Nb, zoo brazing seam forming thiab siab sib koom ua ke. Raws li cov hlau nyiaj filler feem ntau ua rau brazing hlau brittle, lawv yuav tsum zam ntau li ntau tau. Rau cov khoom siv siv ntawm 1000 ℃ thiab 1300 ℃, cov hlau ntshiab Ti, V, Zr lossis alloys raws li cov hlau no uas tsim cov khoom khov thiab kua tsis kawg nrog lawv yuav tsum raug xaiv ua brazing filler hlau. Thaum qhov kub kev pabcuam siab dua, cov hlau filler uas muaj HF tuaj yeem xaiv tau.

W. Saib lub rooj 13 rau kev siv cov hlau filler rau Mo, Ta thiab Nb ntawm qhov kub siab.

Rooj 13 brazing filler metals rau high-temperature brazing ntawm refractory hlau

2. Kev siv tshuab txhuam

Ua ntej yuav siv cov hlau los txhuam, yuav tsum tau ua tib zoo tshem cov oxide tawm ntawm cov hlau uas tsis kub hnyiab. Koj siv tau kev sib tsoo hlau, kev siv xuab zeb los ntxuav, kev siv ultrasonic los ntxuav los yog kev siv tshuaj ntxuav. Yuav tsum siv cov hlau los txhuam tam sim ntawd tom qab ntxuav tas.

Vim yog qhov tsis yooj yim tawg ntawm W, w qhov chaw yuav tsum tau ua tib zoo thaum lub sijhawm sib dhos khoom kom tsis txhob tawg. Yuav kom tiv thaiv tau qhov tsim ntawm brittle tungsten carbide, yuav tsum tsis txhob sib cuag ncaj qha ntawm W thiab graphite. Kev ntxhov siab vim yog kev ua ntej vuam lossis vuam yuav tsum raug tshem tawm ua ntej vuam. W yooj yim heev rau oxidize thaum qhov kub nce. Qhov degree nqus tsev yuav tsum siab txaus thaum lub sijhawm brazing. Thaum brazing ua tiav hauv qhov kub ntawm 1000 ~ 1400 ℃, qhov degree nqus tsev yuav tsum tsis pub tsawg dua 8 × 10-3Pa. Txhawm rau txhim kho qhov kub thiab txias ntawm kev rov yaj thiab kev pabcuam kub ntawm qhov sib koom ua ke, cov txheej txheem brazing tuaj yeem ua ke nrog kev kho mob diffusion tom qab vuam. Piv txwv li, b-ni68cr20si10fel solder siv los braze W ntawm 1180 ℃. Tom qab peb zaug kev kho mob diffusion ntawm 1070 ℃ /4h, 1200 ℃ /3.5h thiab 1300 ℃ /2h tom qab vuam, qhov kub ntawm qhov sib koom ua ke tuaj yeem ncav cuag ntau dua 2200 ℃.

Thaum sib sau ua ke qhov sib koom ua ke ntawm Mo, qhov sib txawv ntawm qhov sib koom ua ke yuav tsum tau coj los xav txog qhov sib txawv me me ntawm thermal expansion. Mo recrystallization tshwm sim thaum nplaim taws brazing, lub cub tawg tswj cua sov, lub cub tawg nqus tsev, lub cub tawg induction thiab cua sov tiv taus tshaj qhov kub recrystallization lossis qhov kub recrystallization txo qis vim yog qhov sib kis ntawm cov khoom siv solder. Yog li ntawd, thaum qhov kub brazing ze rau qhov kub recrystallization, lub sijhawm brazing luv dua, qhov zoo dua. Thaum brazing siab dua qhov kub recrystallization ntawm Mo, lub sijhawm brazing thiab tus nqi txias yuav tsum tau tswj kom tsis txhob tawg los ntawm kev txias sai dhau. Thaum siv oxyacetylene nplaim taws brazing, nws yog qhov zoo tshaj plaws los siv cov flux sib xyaw, uas yog, industrial borate lossis nyiaj brazing flux ntxiv rau cov kub kub uas muaj calcium fluoride, uas tuaj yeem tau txais kev tiv thaiv zoo. Txoj kev yog thawj txheej txheej ntawm cov nyiaj brazing flux rau ntawm qhov chaw ntawm Mo, thiab tom qab ntawd txheej cov kub kub flux. Cov nyiaj brazing flux muaj kev ua haujlwm nyob rau hauv qhov kub qis dua, thiab qhov kub thiab txias ntawm cov kub kub tuaj yeem ncav cuag 1427 ℃.

Cov khoom TA lossis Nb feem ntau yog brazed hauv qab lub tshuab nqus tsev, thiab qib nqus tsev tsis pub tsawg dua 1.33 × 10-2Pa. Yog tias brazing yog ua nyob rau hauv kev tiv thaiv ntawm cov roj inert, cov pa phem xws li carbon monoxide, ammonia, nitrogen thiab carbon dioxide yuav tsum tau tshem tawm nruj me ntsis. Thaum brazing lossis tiv thaiv brazing yog ua nyob rau hauv huab cua, tshwj xeeb brazing filler hlau thiab flux tsim nyog yuav tsum tau siv. Txhawm rau tiv thaiv TA lossis Nb los ntawm kev sib cuag nrog oxygen ntawm qhov kub siab, ib txheej ntawm cov hlau tooj liab lossis nickel tuaj yeem plated rau ntawm qhov chaw thiab sib xws diffusion annealing kev kho mob tuaj yeem ua tiav.