Cuaj qhov kev ua kom raug ntawm cov txheej txheem molding ntawm zirconia ceramics

Cuaj qhov kev ua kom raug ntawm cov txheej txheem molding ntawm zirconia ceramics
Cov txheej txheem molding ua lub luag haujlwm txuas rau hauv tag nrho cov txheej txheem npaj ntawm cov ntaub ntawv ceramic, thiab yog qhov tseem ceeb los xyuas kom meej tias kev ua tau zoo thiab kev rov ua dua ntawm cov ntaub ntawv ceramic thiab cov khoom.
Nrog rau kev txhim kho ntawm lub zej zog, txoj kev sib tsoo tes ib txwm muaj, txoj kev tsim log, txoj kev grouting, thiab lwm yam ntawm cov khoom siv ceramic ib txwm muaj tsis tuaj yeem ua tau raws li qhov xav tau ntawm lub zej zog niaj hnub rau kev tsim khoom thiab kev ua kom zoo nkauj, yog li ntawd cov txheej txheem molding tshiab tau yug los. Cov ntaub ntawv ceramic zoo ZrO2 tau siv dav hauv 9 hom txheej txheem molding hauv qab no (2 hom kev qhuav thiab 7 hom kev ntub dej):

1. Qhuav molding

1.1 Kev nias qhuav

Kev nias qhuav siv lub zog los nias cov hmoov av ua ib yam duab ntawm lub cev. Nws lub ntsiab lus yog tias nyob rau hauv qhov kev ua ntawm lub zog sab nraud, cov hmoov av sib txuas ua ke hauv pwm, thiab sib xyaw ua ke los ntawm kev sib txhuam sab hauv kom tswj tau ib yam duab. Qhov tsis zoo tseem ceeb hauv cov khoom ntsuab qhuav yog spallation, uas yog vim muaj kev sib txhuam sab hauv ntawm cov hmoov thiab kev sib txhuam ntawm cov hmoov thiab phab ntsa pwm, ua rau lub siab poob hauv lub cev.

Qhov zoo ntawm kev nias qhuav yog tias qhov loj ntawm lub cev ntsuab yog qhov tseeb, kev ua haujlwm yooj yim, thiab nws yooj yim rau kev ua haujlwm siv tshuab; cov ntsiab lus ntawm cov dej noo thiab cov binder hauv kev nias qhuav ntsuab yog tsawg dua, thiab qhov ziab thiab hlawv shrinkage yog me me. Nws yog siv los tsim cov khoom nrog cov duab yooj yim, thiab qhov sib piv ntawm cov yam ntxwv yog me me. Qhov nce ntxiv ntawm cov nqi tsim khoom los ntawm kev hnav pwm yog qhov tsis zoo ntawm kev nias qhuav.

1.2 Kev nias Isostatic

Isostatic pressing yog ib txoj kev tsim tshwj xeeb uas tsim los ntawm kev nias qhuav ib txwm muaj. Nws siv lub zog xa dej los siv lub zog sib npaug rau cov hmoov hauv cov pwm elastic los ntawm txhua qhov kev taw qhia. Vim yog qhov sib xws ntawm lub zog sab hauv ntawm cov kua, cov hmoov dais tib lub zog hauv txhua qhov kev taw qhia, yog li qhov sib txawv ntawm qhov ceev ntawm lub cev ntsuab tuaj yeem zam tau.

Kev nias isostatic muab faib ua lub hnab ntub isostatic nias thiab lub hnab qhuav isostatic nias. Lub hnab ntub isostatic nias tuaj yeem tsim cov khoom nrog cov duab nyuaj, tab sis nws tsuas yog ua haujlwm tsis tu ncua. Lub hnab qhuav isostatic nias tuaj yeem ua tiav kev ua haujlwm tas mus li, tab sis tsuas yog tuaj yeem tsim cov khoom nrog cov duab yooj yim xws li square, puag ncig, thiab tubular cross-sections. Isostatic nias tuaj yeem tau txais lub cev ntsuab sib xws thiab ntom, nrog rau kev hlawv me me thiab kev sib xws shrinkage hauv txhua qhov kev taw qhia, tab sis cov khoom siv nyuaj thiab kim, thiab kev ua haujlwm ntau lawm tsis siab, thiab nws tsuas yog tsim nyog rau kev tsim cov ntaub ntawv nrog cov kev xav tau tshwj xeeb.

2. Kev tsim ntub dej

2.1 Kev Siv Cov Pob Zeb
Cov txheej txheem molding grouting zoo ib yam li cov kab xev casting, qhov txawv yog tias cov txheej txheem molding suav nrog cov txheej txheem dehydration lub cev thiab cov txheej txheem coagulation tshuaj. Lub cev dehydration tshem tawm cov dej hauv cov slurry los ntawm kev ua haujlwm capillary ntawm cov pwm porous gypsum. Ca2 + tsim los ntawm kev yaj ntawm qhov chaw CaSO4 ua rau lub zog ionic ntawm cov slurry nce, ua rau cov slurry flocculation.
Nyob rau hauv qhov kev ua ntawm lub cev qhuav dej thiab tshuaj coagulation, cov hmoov av ceramic tau tso rau ntawm phab ntsa pwm gypsum. Grouting yog qhov tsim nyog rau kev npaj cov khoom siv ceramic loj nrog cov duab nyuaj, tab sis qhov zoo ntawm lub cev ntsuab, suav nrog cov duab, qhov ceev, lub zog, thiab lwm yam, tsis zoo, kev siv zog ntawm cov neeg ua haujlwm siab, thiab nws tsis haum rau kev ua haujlwm tsis siv neeg.

2.2 Kub tuag casting
Kev ua pwm kub yog kev sib tov cov hmoov av ceramic nrog cov binder (paraffin) ntawm qhov kub siab (60 ~ 100 ℃) kom tau cov slurry rau kev ua pwm kub. Cov slurry raug txhaj rau hauv cov pwm hlau hauv qab kev ua haujlwm ntawm huab cua compressed, thiab lub siab raug tswj. Txias, demoulding kom tau txais cov quav ciab dawb, cov quav ciab dawb raug dewaxed hauv qab kev tiv thaiv ntawm cov hmoov inert kom tau txais lub cev ntsuab, thiab lub cev ntsuab raug sintered ntawm qhov kub siab kom dhau los ua porcelain.

Lub cev ntsuab uas tsim los ntawm kev kub tuag casting muaj qhov loj me meej, cov qauv sab hauv sib xws, pwm hnav tsawg dua thiab ua haujlwm tau zoo, thiab tsim nyog rau ntau yam khoom siv raw. Qhov kub ntawm cov quav ciab slurry thiab pwm yuav tsum tau tswj hwm nruj me ntsis, txwv tsis pub nws yuav ua rau hauv qab txhaj tshuaj lossis deformation, yog li nws tsis haum rau kev tsim cov khoom loj, thiab cov txheej txheem tua hluav taws ob kauj ruam yog qhov nyuaj thiab kev siv hluav taws xob ntau.

2.3 Kev tsim cov ntaub nplaum
Kev siv cov ntaub nplaum los ua cov khoom siv yog sib tov cov hmoov av ceramic nrog ntau cov organic binders, plasticizers, dispersants, thiab lwm yam kom tau txais cov dej khov uas ntws tau, ntxiv cov dej khov rau hauv lub raj ntawm lub tshuab casting, thiab siv lub scraper los tswj qhov tuab. Nws ntws mus rau txoj siv conveyor los ntawm lub nozzle pub mis, thiab cov zaj duab xis dawb paug tau txais tom qab ziab.

Cov txheej txheem no yog qhov tsim nyog rau kev npaj cov ntaub ntawv zaj duab xis. Yuav kom tau txais kev ywj pheej zoo dua, ntxiv ntau cov organic teeb meem, thiab cov txheej txheem yuav tsum tau tswj hwm nruj me ntsis, txwv tsis pub nws yuav yooj yim ua rau muaj qhov tsis zoo xws li tev tawv, kab txaij, lub zog zaj duab xis qis lossis tev tawv nyuaj. Cov organic teeb meem siv yog lom thiab yuav ua rau muaj kuab paug rau ib puag ncig, thiab yuav tsum siv lub kaw lus tsis muaj kuab lom lossis tsawg dua kom txo tau cov kuab paug rau ib puag ncig.

2.4 Gel txhaj tshuaj molding
Cov txheej txheem txhaj tshuaj gel yog ib qho txheej txheem colloidal rapid prototyping tshiab uas cov kws tshawb fawb ntawm Oak Ridge National Laboratory tau tsim thawj zaug thaum xyoo 1990. Lub hauv paus tseem ceeb yog kev siv cov organic monomer solutions uas polymerize ua cov polymer-solvent gels uas muaj zog heev, txuas rau sab nraud.

Ib qho slurry ntawm cov hmoov av ceramic yaj hauv cov tshuaj ntawm cov organic monomers raug pov rau hauv pwm, thiab cov monomer sib tov polymerizes los ua ib qho gelled. Txij li thaum cov polymer-solvent txuas laterally muaj tsuas yog 10% -20% (pawg feem) polymer, nws yooj yim tshem tawm cov kuab tshuaj ntawm qhov gel los ntawm cov kauj ruam ziab. Tib lub sijhawm, vim yog qhov kev sib txuas sab ntawm cov polymers, cov polymers tsis tuaj yeem tsiv mus nrog cov kuab tshuaj thaum lub sijhawm ziab.

Txoj kev no siv tau los tsim cov khoom siv ceramic ib theem thiab cov khoom sib xyaw ua ke, uas tuaj yeem tsim cov khoom siv ceramic uas muaj cov duab sib txawv, thiab nws lub zog ntsuab yog siab txog 20-30Mpa lossis ntau dua, uas tuaj yeem rov ua dua. Qhov teeb meem tseem ceeb ntawm txoj kev no yog tias qhov nrawm ntawm lub cev embryo yog qhov siab thaum lub sijhawm densification, uas yooj yim ua rau lub cev embryo deformation; qee cov organic monomers muaj oxygen inhibition, uas ua rau qhov chaw tev tawm thiab poob tawm; vim yog qhov kub thiab txias ua rau cov txheej txheem polymerization organic monomer, ua rau kub shaving ua rau muaj kev ntxhov siab sab hauv, uas ua rau cov blanks tawg thiab lwm yam.

2.5 Kev txhaj tshuaj molding ncaj qha
Kev txhaj tshuaj molding ncaj qha yog ib txoj kev siv tshuab molding uas tsim los ntawm ETH Zurich: cov dej yaj, cov hmoov ceramic thiab cov khoom siv organic tau sib xyaw ua ke los tsim cov slurry electrostatically ruaj khov, qis-viscosity, cov khoom muaj zog, uas tuaj yeem hloov pauv los ntawm kev ntxiv Slurry pH lossis cov tshuaj uas ua rau cov electrolyte concentration nce, tom qab ntawd cov slurry raug txhaj rau hauv pwm tsis muaj qhov.

Tswj kev nce qib ntawm cov tshuaj lom neeg thaum lub sijhawm ua haujlwm. Cov tshuaj tiv thaiv ua ntej txhaj tshuaj molding yog ua tiav qeeb qeeb, qhov viscosity ntawm cov slurry yog khaws cia qis, thiab cov tshuaj tiv thaiv yog ua kom nrawm dua tom qab txhaj tshuaj molding, cov slurry khov, thiab cov kua slurry hloov mus ua lub cev khov kho. Lub cev ntsuab tau txais muaj cov khoom siv kho tshuab zoo thiab lub zog tuaj yeem ncav cuag 5kPa. Lub cev ntsuab yog demolded, ziab thiab sintered los ua ib feem ceramic ntawm cov duab xav tau.

Nws qhov zoo yog tias nws tsis xav tau lossis tsuas yog xav tau me ntsis ntawm cov organic additives (tsawg dua 1%), lub cev ntsuab tsis tas yuav tsum tau degreasing, qhov ceev ntawm lub cev ntsuab yog sib xws, qhov ceev sib piv yog siab (55% ~ 70%), thiab nws tuaj yeem tsim cov khoom siv ceramic loj thiab nyuaj. Nws qhov tsis zoo yog tias cov additives kim, thiab roj feem ntau raug tso tawm thaum lub sijhawm tshuaj tiv thaiv.

2.6 Kev txhaj tshuaj molding
Kev txhaj tshuaj molding tau siv ntev los lawm hauv kev molding cov khoom yas thiab kev molding cov pwm hlau. Cov txheej txheem no siv kev kho qhov kub qis ntawm cov thermoplastic organics lossis kev kho qhov kub siab ntawm cov thermosetting organics. Cov hmoov thiab cov organic carrier raug sib xyaw ua ke hauv cov khoom siv sib tov tshwj xeeb, thiab tom qab ntawd txhaj rau hauv pwm hauv qab siab (kaum txog pua pua MPa). Vim yog lub siab molding loj, cov blanks tau txais muaj qhov loj me meej, du thiab cov qauv me me; kev siv cov khoom siv molding tshwj xeeb ua rau kev ua haujlwm ntau ntxiv zoo dua.

Thaum xyoo 1970s thiab xyoo 1980s thaum ntxov, cov txheej txheem txhaj tshuaj molding tau siv rau kev txhaj tshuaj ntawm cov khoom siv ceramic. Cov txheej txheem no ua tiav cov yas molding ntawm cov khoom tsis muaj zog los ntawm kev ntxiv ntau cov organic matter, uas yog cov txheej txheem yas molding ceramic feem ntau. Hauv kev siv tshuab txhaj tshuaj molding, ntxiv rau kev siv cov thermoplastic organics (xws li polyethylene, polystyrene), thermosetting organics (xws li epoxy resin, phenolic resin), lossis cov polymers uas yaj hauv dej ua cov binder tseem ceeb, nws yog qhov tsim nyog los ntxiv qee qhov ntau ntawm cov txheej txheem pab xws li plasticizers, lubricants thiab cov neeg sawv cev txuas kom txhim kho qhov fluidity ntawm cov ceramic txhaj tshuaj ncua thiab xyuas kom meej qhov zoo ntawm lub cev txhaj tshuaj molding.

Cov txheej txheem txhaj tshuaj molding muaj qhov zoo ntawm kev ua haujlwm siab thiab qhov loj ntawm cov pwm yas. Txawm li cas los xij, cov ntsiab lus organic hauv lub cev ntsuab ntawm cov khoom siv ceramic txhaj tshuaj yog siab txog 50vol%. Nws siv sijhawm ntev, txawm tias ob peb hnub txog ntau hnub, kom tshem tawm cov organic no hauv cov txheej txheem sintering tom qab, thiab nws yooj yim ua rau muaj qhov tsis zoo.

2.7 Kev txhaj tshuaj molding Colloidal
Txhawm rau daws cov teeb meem ntawm cov organic ntau ntxiv thiab qhov nyuaj ntawm kev tshem tawm cov teeb meem hauv cov txheej txheem txhaj tshuaj molding ib txwm muaj, Tsinghua University tau tsim cov txheej txheem tshiab rau kev txhaj tshuaj colloidal ntawm cov ceramics, thiab tau tsim ib qho qauv txhaj tshuaj colloidal kom paub txog kev txhaj tshuaj ntawm cov av nplaum ceramic.

Lub tswv yim yooj yim yog kev sib xyaw ua ke ntawm colloidal molding nrog kev txhaj tshuaj molding, siv cov khoom siv txhaj tshuaj tshwj xeeb thiab cov thev naus laus zis tshiab los ntawm cov txheej txheem colloidal in-situ solidification molding. Cov txheej txheem tshiab no siv tsawg dua 4wt.% ntawm cov organic matter. Ib qho me me ntawm cov organic monomers lossis cov organic compounds hauv cov dej-based suspension yog siv los ua kom sai sai polymerization ntawm cov organic monomers tom qab txhaj tshuaj rau hauv pwm los tsim cov organic network skeleton, uas sib npaug qhwv cov hmoov ceramic. Ntawm lawv, tsis yog tsuas yog lub sijhawm ntawm degumming luv dua, tab sis kuj tseem muaj peev xwm ntawm kev tawg ntawm degumming raug txo qis heev.

Muaj qhov sib txawv loj heev ntawm kev txhaj tshuaj molding ntawm ceramics thiab colloidal molding. Qhov sib txawv tseem ceeb yog tias tus thawj koom nrog pawg ntawm yas molding, thiab tus tom kawg koom nrog slurry molding, uas yog, cov slurry tsis muaj plasticity thiab yog cov khoom siv tsis muaj txiaj ntsig. Vim tias cov slurry tsis muaj plasticity hauv colloidal molding, lub tswv yim ib txwm ntawm ceramic txhaj tshuaj molding tsis tuaj yeem siv tau. Yog tias colloidal molding yog ua ke nrog kev txhaj tshuaj molding, colloidal txhaj tshuaj molding ntawm cov khoom siv ceramic yog ua tiav los ntawm kev siv cov khoom siv txhaj tshuaj tshwj xeeb thiab cov thev naus laus zis tshiab los ntawm colloidal hauv-situ molding txheej txheem.

Cov txheej txheem tshiab ntawm kev txhaj tshuaj colloidal ntawm cov khoom siv ceramics txawv ntawm kev txhaj tshuaj colloidal dav dav thiab kev txhaj tshuaj molding ib txwm muaj. Qhov zoo ntawm qib siab ntawm kev siv tshuab molding yog qhov zoo ntawm cov txheej txheem molding colloidal, uas yuav dhau los ua kev cia siab rau kev lag luam ntawm cov khoom siv ceramics siab.