Cov tshuaj tiv thaiv sintering
Cov tshuaj tiv thaiv sinteringsilicon carbide ceramicCov txheej txheem tsim muaj xws li ceramic compacting, sintering flux infiltration agent compacting, cov tshuaj tiv thaiv sintering ceramic khoom npaj, silicon carbide wood ceramic npaj thiab lwm cov kauj ruam.
Cov tshuaj tiv thaiv sintering silicon carbide nozzle
Ua ntej, 80-90% ntawm cov hmoov ceramic (muaj li ntawm ib lossis ob lub hmoov ntawmsilicon carbide hmoovthiab boron carbide hmoov), 3-15% ntawm cov pa roj carbon monoxide hmoov (muaj ib los yog ob ntawm cov pa roj carbon dub thiab phenolic resin) thiab 5-15% ntawm molding tus neeg sawv cev (phenolic resin, polyethylene glycol, hydroxymethyl cellulose los yog paraffin) sib tov sib npaug. siv lub pob zeb kom tau txais cov hmoov sib xyaw, uas yog cov tshuaj tsuag qhuav thiab granulated, thiab tom qab ntawd nias rau hauv pwm kom tau txais cov pob zeb ceramic nrog ntau yam tshwj xeeb. cov duab.
Thib ob, 60-80% silicon hmoov, 3-10% silicon carbide hmoov thiab 37-10% boron nitride hmoov sib tov sib xyaw, thiab nias rau hauv pwm kom tau txais sintering flux infiltration agent compact.
Ceramic compact thiab sintered infiltrant compact yog ces stacked ua ke, thiab qhov kub yog nce mus rau 1450-1750 ℃ nyob rau hauv lub tshuab nqus tsev vacuum degree ntawm tsis tsawg tshaj li 5 × 10-1 Pa rau sintering thiab kub preservation rau 1-3. teev kom tau txais cov tshuaj tiv thaiv sintered ceramic khoom. Lub infilttrant seem nyob rau saum npoo ntawm sintered cerameded ceramin raug tshem tawm kom tau cov ntawv ceramic, thiab cov qauv qub ntawm cov kev cog lus Ceracic.
Thaum kawg, cov txheej txheem sintering tau txais yuav, uas yog, kua silicon los yog silicon alloy nrog cov tshuaj tiv thaiv kev ua haujlwm ntawm qhov kub thiab txias infiltrates mus rau hauv cov porous ceramic blanks uas muaj cov pa roj carbon nyob rau hauv qhov kev txiav txim ntawm capillary quab yuam, thiab reacts nrog cov pa roj carbon nyob rau hauv daim ntawv silicon carbide, uas. yuav nthuav nyob rau hauv ntim, thiab cov pores seem yog sau nrog elemental silicon. Cov porous ceramic blanks tuaj yeem yog cov pa roj carbon ntshiab lossis silicon carbide / carbon-based composite khoom. Cov qub yog tau los ntawm catalytically kho thiab pyrolyzing ib qho organic resin, lub pore qub thiab hnyav. Cov tom kawg yog tau los ntawm pyrolyzing silicon carbide particles / resin-raws li cov ntaub ntawv sib xyaw kom tau txais silicon carbide / carbon-based composite cov ntaub ntawv, los yog siv α-SiC thiab carbon hmoov ua cov khoom pib thiab siv cov txheej txheem nias lossis txhaj tshuaj molding kom tau txais cov khoom sib xyaw. khoom.
Pressureless sintering
Cov txheej txheem tsis muaj zog sintering ntawm silicon carbide tuaj yeem muab faib ua cov khoom-theem sintering thiab kua-theem sintering. Nyob rau hauv xyoo tas los no, kev tshawb fawb ntawmsilicon carbide ceramicsHauv tsev thiab txawv teb chaws tau tsom mus rau cov kua-theem sintering. Cov txheej txheem kev npaj ceramic yog: cov khoom sib xyaw pob milling-> tshuaj tsuag granulation-> qhuav nias-> ntsuab lub cev solidification-> nqus sintering.
Cov khoom siv tsis muaj zog sintered silicon carbide
Ntxiv 96-99 qhov chaw ntawm silicon carbide ultrafine hmoov (50-500nm), 1-2 qhov chaw ntawm boron carbide ultrafine hmoov (50-500nm), 0.2-1 qhov chaw ntawm nano-titanium boride (30-80nm), 10-20 qhov chaw ntawm dej-soluble phenolic resin, thiab 0.1-0.5 feem ntawm high-efficiency dispersant rau lub pob zeb rau pob milling thiab sib tov rau 24 xuab moos, thiab muab cov slurry sib xyaw rau hauv ib lub thoob sib tov rau 2 teev kom tshem tawm npuas hauv slurry.
Cov sib tov saum toj no yog txau rau hauv cov pej thuam granulation, thiab cov hmoov granulation nrog zoo particle morphology, zoo fluidity, nqaim particle faib ntau thiab nruab nrab noo noo yog tau los ntawm kev tswj cov tshuaj tsuag siab, cua inlet kub, cua qhov hluav taws xob kub thiab tshuaj tsuag daim ntawv particle loj. Lub centrifugal zaus hloov dua siab tshiab yog 26-32, cua inlet kub yog 250-280 ℃, cua qhov hluav taws xob kub yog 100-120 ℃, thiab slurry inlet siab yog 40-60.
Cov hmoov granulation saum toj no muab tso rau hauv cov cemented carbide pwm rau nias kom tau txais lub cev ntsuab. Txoj kev nias yog bidirectional siab, thiab lub tshuab cuab yeej siab tonnage yog 150-200 tons.
Lub cev ntsuab nias tau muab tso rau hauv qhov cub kom qhuav kom qhuav thiab kho kom tau txais lub cev ntsuab nrog lub cev ntsuab zoo zog.
Sab saum toj kho ntsuab lub cev yog muab tso rau hauv ibgraphite cruciblethiab npaj kom zoo thiab zoo, thiab tom qab ntawd cov graphite crucible nrog lub cev ntsuab yog muab tso rau hauv lub tshuab nqus tsev kub kub sintering rau hluav taws kub. Qhov hluav taws kub kub yog 2200-2250 ℃, thiab lub sij hawm rwb thaiv tsev yog 1-2 teev. Thaum kawg, high-performance pressureless sintered silicon carbide ceramics tau txais.
Khoom-theem sintering
Cov txheej txheem tsis muaj zog sintering ntawm silicon carbide tuaj yeem muab faib ua cov khoom-theem sintering thiab kua-theem sintering. Ua kua-theem sintering yuav tsum tau ntxiv cov sintering additives, xws li Y2O3 binary thiab ternary additives, ua SiC thiab nws cov ntaub ntawv uas muaj tam sim no kua-theem sintering thiab ua kom tiav densification ntawm qis kub. Txoj kev npaj ntawm cov khoom-theem sintered silicon carbide ceramics suav nrog kev sib xyaw ntawm cov khoom siv raw, tshuaj tsuag granulation, molding, thiab nqus sintering. Cov txheej txheem tsim khoom tshwj xeeb yog raws li hauv qab no:
70-90% ntawm submicron α silicon carbide (200-500nm), 0.1-5% ntawm boron carbide, 4-20% resin, thiab 5-20% ntawm cov organic binder muab tso rau hauv ib lub tov khoom thiab ntxiv nrog dej ntshiab rau ntub dej. sib tov. Tom qab 6-48 teev, cov slurry sib xyaw yog dhau los ntawm 60-120 mesh sieve;
Lub sieved slurry yog txau granulated los ntawm ib tug tshuaj tsuag granulation ntauwd. Inlet kub ntawm cov tshuaj tsuag granulation ntauwd yog 180-260 ℃, thiab qhov hluav taws xob kub yog 60-120 ℃; Qhov ceev ntawm cov khoom granulated yog 0.85-0.92g / cm3, fluidity yog 8-11s / 30g; cov khoom siv granulated yog sieved los ntawm 60-120 mesh sieve rau tom qab siv;
Xaiv cov pwm raws li cov khoom xav tau, thauj cov khoom siv granulated rau hauv cov pwm kab noj hniav, thiab ua rau chav tsev kub compression molding ntawm lub siab ntawm 50-200MPa kom tau txais lub cev ntsuab; los yog tso lub cev ntsuab tom qab compression molding rau hauv isostatic nias ntaus ntawv, ua isostatic nias ntawm lub siab ntawm 200-300MPa, thiab tau txais lub cev ntsuab tom qab nias thib ob;
Muab lub cev ntsuab npaj rau hauv cov kauj ruam saum toj no rau hauv lub tshuab nqus tsev sintering rau sintering, thiab qhov tsim nyog yog cov khoom tiav silicon carbide bulletproof ceramic; Nyob rau hauv cov txheej txheem sintering saum toj no, thawj zaug tshem tawm lub sintering rauv, thiab thaum lub tshuab nqus tsev kawm ntawv nce mus txog 3-5 × 10-2 Tom qab Pa, cov roj inert yog kis mus rau hauv lub sintering rauv rau ib txwm siab thiab ces rhuab. Kev sib raug zoo ntawm cov cua kub thiab lub sij hawm yog: chav tsev kub rau 800 ℃, 5-8 teev, txuag tshav kub rau 0.5-1 teev, los ntawm 800 ℃ mus rau 2000-2300 ℃, 6-9 teev, kub preservation rau 1 mus rau 2 teev, thiab tom qab ntawd txias nrog lub cub tawg thiab poob rau hauv chav tsev kub.
Microstructure thiab grain ciam teb ntawm silicon carbide sintered ntawm ib txwm siab
Hauv luv luv, ceramics tsim los ntawm cov txheej txheem kub nias sintering muaj kev ua tau zoo dua, tab sis cov nqi tsim khoom kuj tseem nce ntxiv; ceramics npaj los ntawm pressureless sintering muaj ntau dua raw cov ntaub ntawv uas yuav tsum tau, siab sintering kub, loj khoom loj hloov, complex txheej txheem thiab tsis tshua muaj kev ua tau zoo; Cov khoom lag luam muaj tej yam tsim los ntawm cov txheej txheem Sintering Sintering muaj kev ua siab loj, cov nqi zog zoo, thiab cov kev npaj tsawg. Ntau yam kev npaj sintering ntawm silicon carbide ceramics muaj lawv tus kheej qhov zoo thiab qhov tsis zoo, thiab daim ntawv thov scenarios kuj yuav txawv. Nws yog txoj cai zoo tshaj plaws los xaiv txoj kev npaj kom raug raws li cov khoom lag luam thiab nrhiav kev sib npaug ntawm tus nqi qis thiab kev ua haujlwm siab.
Post lub sij hawm: Oct-29-2024