Cov khoom ntawm tungsten hlau hmoov

Kev ua tau zoo ntawm tungsten hmoov muaj qhov cuam tshuam loj rau kev ua haujlwm thiab kev ua tau zoo ntawm cov khoom tom ntej. Yog li ntawd, ob qho tib si hard alloy teb thiab tungsten cov ntaub ntawv ua teb tau muab tso rau hauv cov kev cai sib xws rau cov tshuaj purity thiab lub cev khoom ntawm raw tungsten hmoov, tshwj xeeb tshaj yog cov yuav tsum tau rau lub cev muaj zog zog thiab siab dua. 

Tshuaj purity

Thaum tsim cov cemented carbide thiab tungsten cov khoom, cov tshuaj purity ntawm tungsten hmoov yuav tsum tau siab heev. Cov khoom seem impurity nyob rau hauv tungsten hmoov muaj kev cuam tshuam rau kev ua haujlwm thiab kev pabcuam kev ua haujlwm ntawm cov khoom. Cov cawv yog qhov nyuaj heev, nrog qee qhov ua rau muaj kev phom sij thiab qee qhov muaj txiaj ntsig. Kev tshawb fawb tam sim no qhia tias Ca, Mg, P, As, Si, S, Fe, Ni, Cu, Al, thiab Mo tuaj yeem txo lub zog ntawm cov hlau, thaum K thiab Na txhawb kev loj hlob ntawm WC nplej. V thiab Cr, ntawm qhov tod tes, inhibit qhov kev loj hlob ntawm cov nplej. Yog tias cov ntsiab lus Mo hauv WO tshaj 0.5%, nws yuav ua rau txo qis ntawm lub zog flexural ntawm cov hlau. Nyob rau hauv feem ntau tungsten hmoov ntau yam tam sim no tsim, cov ntsiab lus ntawm residual metallic impurities (tsis suav cov ntxiv raws li additives) yog nyob rau hauv ntau ntawm ob peb qhov chaw ntawm kaum txhiab mus rau ob peb qhov chaw ntawm ib puas txhiab. 

Cov pa oxygen hauv tungsten hmoov tuaj yeem hnov ​​mob nrog carbides, absorbing carbon los ntawm carbides thiab ua rau decarburization ntawm cemented carbide. Thaum lub alloy yog decarburized hnyav, lub γ theem tshwm, ua rau cov alloy nkig. Cov roj tso tawm los ntawm cov tshuaj tiv thaiv nce qhov porosity ntawm cov hlau thiab txo nws lub zog. Nyob ntawm qhov sib txawv ntawm kev txo cov txheej txheem thiab cov khoom siv, cov ntsiab lus oxygen hauv tungsten hmoov feem ntau yog nruab nrab ntawm 0.05% thiab 0.5%, thiab nws nce nrog qhov txo qis hauv tungsten hmoov particle loj thiab qhov nce hauv thaj chaw tshwj xeeb. Yog li, qhov yuav tsum tau muaj cov ntsiab lus ntawm cov pa oxygen hauv cov hmoov nplej zoo tungsten yuav tsum tau so kom tsim nyog. Cov tshuaj purity yuav tsum muaj rau tungsten hmoov yog qhia nyob rau hauv Table 4-1, thiab cov ntsiab lus ntawm cov pa oxygen yuav tsum tau qhia nyob rau hauv Table 4-2.

Cov ntsiab lus impurity nyob rau hauv tungsten hmoov tuaj yeem los ntawm cov khoom siv raw lossis raug qhia thaum lub sijhawm tsim khoom. Yog li ntawd, kev tiv thaiv kev sib kis ntawm cov ntaub ntawv thaum lub sij hawm txheej txheem yog qhov tseem ceeb heev. Piv txwv li, hauv kev tsim cov tungsten hmoov siv APT raws li cov khoom siv raw, cov ntaub ntawv tuaj rau hauv kev sib cuag ncaj qha nrog cov calcining rauv, txo cov tub rauv, thiab crucibles, ua rau muaj kev nce hauv cov ntsiab lus ntawm impurities xws li Fe, Ni, Cr, thiab Si, thiab txo cov tshuaj purity. Thaum lawv cov ntsiab lus nce mus txog ib qib lossis lawv sib sau ua ke rau qhov loj txaus, lawv tuaj yeem dhau los ua qhov tsis xws luag rau kev ua tom ntej lossis siv. Yog li ntawd, txhawm rau xyuas kom meej lub purity ntawm tungsten hmoov, ntxiv rau nruj tswj qhov zoo ntawm cov khoom raw APT, nws tseem ceeb heev kom tsis txhob muaj kab mob thaum lub sij hawm tus txheej txheem. 

2. Lub cev muaj zog

The physical properties of metallic tungsten powder mainly include average particle size, particle size distribution, particle aggregation degree, particle morphology, specific surface area, bulk density, compacted density, and Hall flow rate, etc. 

(Qhov nruab nrab particle loj thiab particle loj faib)

Txawm hais tias nws yog cemented carbide lossis tungsten cov khoom, muaj cov kev cai nruj rau qhov nruab nrab particle loj thiab particle loj faib ntawm tungsten hmoov. Hauv thaj tsam ntawm cemented carbide, qhov loj me me thiab qhov loj me me ntawm W hmoov ncaj qha cuam tshuam rau qhov loj me thiab qhov loj me me ntawm cov khoom tsim WC hmoov. Qhov loj me me ntawm WC hmoov ntxiv cuam tshuam rau kev ua haujlwm ntawm cov khoom siv cemented carbide. 

Cov kev tshawb fawb tau pom tias cov khoom ntawm WC hmoov raug txwv los ntawm cov hmoov WC. Tom qab W hmoov yog carbonized los ua WC, qhov loj me me tau hloov me ntsis. Txhawm rau tsim WC hmoov ntawm ntxhib, nruab nrab thiab nplua particle qhov ntau thiab tsawg, ntxhib, nruab nrab thiab zoo particle W hmoov yuav tsum tau siv. Uneven W hmoov carbonization ua rau tsis sib xws WC hmoov. Cov kev hloov ntawm cov hmoov particle loj tom qab carbonization ntawm ntxhib, nruab nrab thiab zoo particle W hmoov yog qhia nyob rau hauv Table 4-3.

Cov kev cai rau tungsten hmoov particle loj sib txawv ntawm cov neeg siv sib txawv. Rau qhov nyuaj alloy teb, rau ntau hom tawv alloys siv rau cov hom phiaj sib txawv, vim qhov sib txawv particle ntau thiab tsawg ntawm WC hmoov siv, muaj cov kev cai sib txawv rau qhov nruab nrab particle loj thiab particle loj muaj pes tsawg leeg ntawm raw khoom W hmoov. Tag nrho cov cuab yeej txiav yuav tsum muaj W hmoov thiab WC hmoov kom muaj qhov loj me me thiab qhov nqaim me me faib. Cov cuab yeej cuam tshuam xav tau W hmoov thiab WC hmoov kom ntxhib, nrog rau qhov dav dua qhov loj me. Qhov nruab nrab particle loj siv rau kev npaj coarse-grained WC yog 25.8 μm. Tus neeg sawv cev particle loj faib ntawm W hmoov yog qhia hauv daim duab 4-1.

Rau kev ua cov khoom siv tungsten, qhov nruab nrab qhov loj me thiab qhov loj me me ntawm tungsten hmoov muaj kev cuam tshuam rau kev ua haujlwm ntawm cov khoom tom ntej, qhov ntom ntawm lub cev ntsuab (tseem hu ua lub cev nias), thiab kev ua haujlwm sintering. Cov hmoov me me me me thiab cov duab ntau dua yuav ua rau muaj kev sib txhuam ntau dua ntawm cov khoom, ua rau txo qis ntawm qhov ntom ntawm lub cev ntsuab. Qhov nqaim dua qhov particle loj faib, qhov ntau loosely cov hais yog teem. Qhov loj dua particle tis, los yog sib tov hmoov ntawm qhov sib txawv nruab nrab particle qhov ntau thiab tsawg, tuaj yeem ua tiav cov khoom zoo dua qub thiab tau txais lub zog ntsuab ntau dua. Nyob rau hauv cov ntaub ntawv tungsten ua teb, qhov nruab nrab particle loj ntawm tungsten hmoov feem ntau yuav tsum nyob rau hauv thaj tsam ntawm 2 mus rau 6 μm. 

Muaj ntau txoj hauv kev los txiav txim siab hmoov particle loj thiab particle loj faib. Fischers 'apparatus thiab laser particle loj analyzer yog dav siv nyob rau hauv tungsten hmoov. Txawm li cas los xij, vim muaj cov ntsiab lus sib txawv ntawm ob txoj kev ntsuas no, qhov ntsuas qhov ntsuas tau los ntawm tib cov hmoov yuav txawv. Yog li ntawd, qhov loj me me ntawm tungsten hmoov yuav tsum tau hais raws li Fischers 'qhov nruab nrab particle loj lossis laser nruab nrab particle loj. Tsis tas li ntawd, nws yuav tsum raug sau tseg tias "lub xeev muab khoom" tungsten hmoov feem ntau muaj qhov sib txawv ntawm cov agglomeration, uas muaj feem xyuam rau cov khoom siv. Qhov nruab nrab particle loj ntawm tungsten hmoov ntsuas siv cov qauv no yuav txawv ntawm qhov tseeb particle loj ntawm cov hmoov. Piv txwv li, qhov loj me me ntawm qee qhov dull nplua tungsten hmoov nyob rau hauv "lub xeev muab khoom" yog 1-2 μm, thiab tom qab depolymerization thiab dispersion, tus nqi poob rau 0.4-0.5 μm. Rau tungsten hmoov nrog qhov ntau thiab tsawg ntawm 1-10 μm, feem ntau, ntsuas qhov "muab lub xeev" particle loj tuaj yeem ua tau raws li qhov yuav tsum tau ua. Rau submicron tungsten hmoov thiab coarser tungsten hmoov, txhawm rau kom paub meej qhov loj ntawm cov khoom, cov qauv "sib tsoo lub xeev" yuav tsum tau siv rau qhov nruab nrab particle loj thiab particle loj qhov kev ntsuam xyuas. 

Tnws particle loj tis ntawm tungsten hmoov muaj feem xyuam rau nws particle loj. Feem ntau, qhov loj dua qhov nruab nrab particle loj ntawm tungsten hmoov, qhov dav ntawm particle loj tis. Rau qhov loj me me, hauv kev tsim khoom, txoj hauv kev xws li siv cov dej ntub dej los yog ntxiv cov tshuaj alkali hlau rau cov tungsten oxide tuaj yeem ua rau cov particle loj dua thiab tswj cov particle loj faib ntau nqaim. Kev txiav txim siab ntawm particle loj faib feem ntau yog ua los ntawm kev siv "hauv av xeev" cov qauv. 

Qhov nruab nrab particle loj ntawm tungsten hmoov feem ntau qhia los ntawm nws txoj kab uas hla (hauv micrometers). Txawm li cas los xij, hauv kev xyaum ntau lawm, qee cov ntsiab lus ib nrab yog feem ntau siv. Cov kev faib ua feem ntau suav nrog: 

Cov lus ntxhib heev: Qhov nruab nrab qhov loj me> 30 μm; 

30 μm; 

Coarse hais: nruab nrab particle loj 10 mus rau 30 μm; 

Cov khoom me me: nruab nrab particle loj 3 mus rau 10 μm; 

Fine particles: Nruab nrab particle loj 0.5 - 3 μm; 

Ultrafine hais: nruab nrab particle loj

(2) Aggregation degree

Kev sib sau ua ke ntawm cov hmoov feem ntau yog qhov sib txawv ntawm qhov loj me ntawm "muab lub xeev" hmoov thiab "hauv av xeev" hmoov. Kev sib sau ua ke ntawm cov hmoov zoo tungsten feem ntau siab dua li cov hmoov tungsten ntxhib. Rau kev tsim cov khoom siv tungsten, qhov kev sib sau ua ke ncaj qha cuam tshuam rau lub zog ntawm daim ntsuab. Hauv cov txheej txheem tsim khoom WC, qhov sib sau ua ke ntawm w hmoov muaj kev cuam tshuam rau kev sib luag ntawm cov pa roj carbon monoxide. 

(3) Particle morphology

Lub particle morphology ntawm tungsten hmoov muaj kev cuam tshuam rau nws cov kev ua haujlwm nias thiab lub zog ntawm lub cev ntsuab. Irregular particle morphology ua rau kev cuam tshuam ntawm cov khoom, yog li txhim kho lub zog ntawm lub cev ntsuab. Spherical tungsten hmoov muaj fluidity zoo thiab tshwj xeeb tshaj yog haum rau cov ntaub ntawv txau. Ib yam li ntawd, thaum npaj WC, morphology ntawm tungsten hmoov kuj cuam tshuam rau morphology ntawm WC hmoov. 

(4) Qhov chaw tshwj xeeb

Tag nrho cov cheeb tsam saum npoo uas muaj los ntawm ib chav tsev loj ntawm tungsten hmoov raug xa mus rau qhov chaw tshwj xeeb ntawm tungsten hmoov, uas feem ntau yog qhia hauv units ntawm m2·g-1. Qhov chaw tshwj xeeb ntawm tungsten hmoov feem ntau yog li ntawm 0.01 txog 12 m2·g-1. Nws tsis ncaj qha cuam tshuam txog qhov loj me thiab cov qauv ntawm cov tungsten hmoov thiab yog ib qho tseem ceeb qhia rau kev ntsuam xyuas cov kev ua sintering, dissolution yam ntxwv, thiab muaj peev xwm tshuaj tiv thaiv nrog gaseous thiab khoom khoom thaum lub sij hawm carbonization txheej txheem ntawm tungsten hmoov. 

(5) Qhov ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom

The loose density and compacted density of tungsten powder increase with the increase of the average particle size of the powder. Txoj kev sib raug zoo ntawm qhov ntom ntom ntawm tungsten hmoov uas tsim los ntawm ib lub Hoobkas thiab nws cov Fischers 'qhov nruab nrab particle loj yog qhia nyob rau hauv Table 4-4. Qhov nqaim ntawm qhov loj me me ntawm cov hmoov sib faib, qhov nyuaj ntawm cov particle morphology, thiab qhov hnyav dua qhov sib sau ua ke, qhov me dua qhov ntom ntom. Feem ntau, cov txheej txheem ntawm cov txheej txheem txo qis tuaj yeem hloov kho kom tswj tau nws.

(6) Fluidity

Lub fluidity ntawm tungsten hmoov yog cuam tshuam los ntawm particle loj, particle loj tis, thiab particle morphology. Lub coarser cov hmoov hais, lub rounder particles, thiab lub smoother nto, qhov zoo dua lub fluidity. Lub fluidity ntawm tungsten hmoov feem ntau yog ntsuas los ntawm Hall flow rate, uas yog qhia raws li lub sij hawm nws yuav siv sij hawm rau 50g ntawm tungsten hmoov ntws los ntawm ib tug tshwj xeeb qhov me me nyob rau hauv ib tug Hall flow meter. Lub fluidity ntawm cov hmoov ncaj qha cuam tshuam lub ntim ntim thaum lub sij hawm nias txheej txheem thiab cov uniformity ntawm cov tuag-cam khwb cia ntom ntom. 

(7)Compressibility

Compressibility yog hais txog lub peev xwm ntawm tungsten hmoov kom compressed nyob rau hauv cov txheej txheem nias. Nws feem ntau yog ntsuas hauv cov pwm pwm raws li cov txheej txheem lubrication, thiab qhia los ntawm cov hmoov qhov ntom ntom ntawm cov khoom nias nyob rau hauv lub siab ceev. Nws kuj tseem tuaj yeem sawv cev los ntawm cov duab nkhaus uas qhia txog kev hloov pauv ntawm cov khoom siv xovxwm nrog nias lub zog. 

(8) Formability