Raws li cov khoom siv kub kub, mullite muaj cov yam ntxwv ntawm qhov siab softening point nyob rau hauv load, zoo creep kuj thiab tshuaj tsis kam, tsis tshua muaj thermal expansion coefficient, thiab zoo thermal stability. Thaum tsis muaj cov khoom siv sab nraud, mullite yog ib qho yooj yim los tsim ntawm cov ciam teb. Lub iav theem cuam tshuam rau kev ua haujlwm kub ntawm cov khoom siv; Thaum tsim cov corundum-mullite cov khoom sib xyaw nrog corundum, nws tuaj yeem txo qhov tsim ntawm iav theem thiab txhim kho cov khoom siv kho tshuab. Cov khoom sib xyaw corundum-mullite concentrates ob qho tib si corundum thiab mullite. Qhov zoo ntawm cov khoom siv ib-theem no, nws muaj lub zog kub zoo heev, kev nkag siab tsis kam, thermal poob siab thiab kev siv siab dua (1650 degree), nws cov tshuaj lom neeg ruaj khov yog qhov zoo, thiab nws tsis yooj yim rau kev hnov mob nrog cov khoom hlawv, tshwj xeeb tshaj yog Haum rau firing mos magnetic (ferrite) cov ntaub ntawv thiab hluav taws xob insulating ceramics. Tam sim no, high-temperature push-slab kilns feem ntau siv corundum-mullite kiln rooj tog. Piv nrog rau cov khoom txawv teb chaws, cov pob zeb hauv tsev muaj lub neej qis thiab kev ruaj ntseg Tsis zoo, qhov hnav tsis kam thiab khoov lub zog thaum lub sij hawm thov tsis zoo, thiab nws yog ib qho yooj yim rau hnav thiab tawg thaum siv, tshwj xeeb tshaj yog thermal shock stability thiab creep. tsis zoo tagnrho, uas yog cov laj thawj tseem ceeb rau kev ua haujlwm tsis zoo ntawm lub laub phaj. Cov qauv txiav txim siab cov khoom. Txij li thaum corundum, mullite hais thiab cov hmoov zoo yuav tsis koom nrog cov tshuaj tiv thaiv thaum lub sij hawm tua, cov khoom thiab cov qauv ntawm cov khoom siv corundum-mullite yog txiav txim siab los ntawm cov ntsiab lus ntawm silica hmoov thiab -Al2O3 hmoov thiab qhov kub thiab txias. Kev txiav txim siab. Yog li ntawd, nws yog qhov tseem ceeb tshaj plaws los kawm txog kev cuam tshuam ntawm micronized hmoov thiab tua hluav taws kub ntawm qhov kev ua haujlwm kub ntawm cov ntaub ntawv corundum-mullite. Tam sim no, kev tshawb fawb ntawm corundum-mullite cov ntaub ntawv hauv tsev thiab txawv teb chaws feem ntau yog ib qho kev tsom xam, uas cuam tshuam nrog kev tswj xyuas tiag tiag. Muaj qhov sib txawv loj. Raws li kev tsim kho kom zoo ntawm cov theem particle muaj pes tsawg leeg thiab gradation, daim ntawv no tswj cov microstructure ntawm corundum-mullite puas ceramics los ntawm kev sim orthogonal ntawm silica micropowder, alumina micropowder thiab firing kub rau high-temperature zog. , Txhawm rau txhim kho qhov kub thiab txias ntawm multiphase ceramics.
kev sim
1.1 Cov khoom siv raw
Qhov nruab nrab particle loj ntawm -Al2O3 micropowder thiab dawb corundum yog qis dua 5μm; SiO2 micropowder yog muab los ntawm Elkem, Norway, nrog ib feem ntawm 98.3 feem pua, thiab nws qhov nruab nrab particle loj yog 5.917μm; cov khoom siv yog tabular corundum, dawb corundum thiab hluav taws xob Melt mullite muaj ob qhov loj me specifications: 0-1mm thiab 1-3mm.
1.2 Kev txiav txim siab ntawm qhov kev sim ntsuas
Yog hais tias qhov cuam tshuam ntawm impurities ntawm cov khoom ntawm corundum-mullite cov ntaub ntawv raug tsis saib xyuas lossis cuam tshuam ntawm impurities ntawm cov khoom ntawm corundum-mullite cov ntaub ntawv raug suav tias yog tib yam, txij li corundum, mullite particles thiab hmoov zoo yuav tsis koom nrog cov tshuaj tiv thaiv thaum lub sijhawm. Cov txheej txheem tua hluav taws, Nws tuaj yeem txiav txim siab tias qhov kev ua tau zoo ntawm cov khoom siv corundum-mullite feem ntau yog txiav txim siab los ntawm qhov loj ntawm silica hmoov thiab -Al2O3 hmoov thiab qhov kub thiab txias. Raws li cov kev xeem dhau los thiab cov ntaub ntawv [9], qhov kev mob ntawm orthogonal tuaj yeem txiav txim siab raws li: w(-Al2O3 Micropowder) yog 7 feem pua, 9 feem pua, 11 feem pua, feem; w (SiO2 micropowder) yog 3 feem pua, 3.5 feem pua, 4 feem pua, feem; Qhov hluav taws kub kub yog 1600, 1650, 1700 degree, feem.
1.3 Multiphase ceramic formula
Lub m (corundum): m (mullite) nyob rau hauv lub binding theem yog kwv yees li 75: 25, thiab qhov loj feem ntawm lub binding theem yog 36 feem pua rau 38 feem pua. Cov khoom xyaw zaum kawg muaj Al2O3 nrog ib feem loj ntawm 70 feem pua rau 81 feem pua thiab SiO2 nrog ib feem ntawm 19 feem pua -30 feem pua.
Nyob rau hauv txoj kev tshawb no, los ntawm kev kho qhov loj feem thiab firing kub ntawm SiO2 micropowder thiab -Al2O3 micropowder, lub microstructure ntawm corundum-mullite puas ceramics tau tswj kom ua tiav lub hom phiaj ntawm kev txhim kho qhov kub-kub lub zog ntawm composite ceramics. Raws li cov classic nruam tsub zuj zuj txoj kev xav, Andreasen siv U(Dp)=100.(Dp/Dpmax)q sawv cev rau qhov ceev tis, qhov twg U(Dp) yog cov cumulative feem pua nyob rau hauv lub sieve (feem pua), Dpmax yog tus qhov siab tshaj particle loj, thiab q yog Fuller index. Qhov kev ntsuam xyuas qhia tau hais tias thaum q= Kev sib sau ntawm cov khoom sib txuas tsis tu ncua ntawm 0.33-0.50 muaj qhov sib piv me me. Nyob rau hauv txoj kev tshawb no, q=0.45, kom cov particle theem siv muaj ib tug denser packing qauv. Ntawm lawv, muaj pes tsawg leeg ntawm 1#-9# hais yog 1-3 hli Corundum theem, qhov loj feem yog 47 feem pua ; 0-1mm fused mullite, qhov loj feem yog 15 feem pua.
1.4 Kev sim txoj kev
Cov hmoov siv raws li lub sijhawm khi yog sib xyaw nrog lub pob zeb, thiab lub sijhawm sib xyaw yog 12h. Cov theem particle yog sib xyaw ua ke raws li cov qauv tsim, thiab qhov tsim nyog ntawm polyvinyl cawv yog ntxiv rau do, thiab tom qab ntawd ntxiv cov txheej txheem khi, thiab cov khoom raug tso tawm tom qab sib tov sib npaug. Nws yog tsim los ntawm ib tug xovxwm. Tom qab cov qauv tsim tau qhuav, lawv raug rho tawm haujlwm ntawm 1600, 1650 thiab 1700 degree raws li, thiab lub sijhawm tuav yog 4h.
Lub cev thiab lub zog ntawm cov qauv raug rho tawm haujlwm yog ua raws li cov qauv hauv tebchaws uas cuam tshuam. Qhov kev ntsuas thermal stability tau txais cov txheej txheem dej txias. Cov qauv 25mm × 25mm × 125mm yog siv ncaj qha rau kev kuaj. Lub qhov cub kub kub yog rhuab mus rau 1100 degree, thiab cov qauv yog muab tso rau hauv Tom qab tsa qhov kub thiab txias mus rau 1100 degree dua nyob rau lub sij hawm ntawm lub sij hawm, khaws cia rau 30 feeb, tshem tawm thiab muab tso rau hauv dej txias chav tsev (txog 20 degree) kom txias sai sai rau 3 feeb, thiab siv feem pua ntawm cov khoom seem ntawm cov qauv los ua tus yam ntxwv ntawm thermal stability ntawm cov khoom. Creep resistance test tej yam kev mob Yuav kom qhov kub thiab txias ntawm 1600 degree hauv huab cua rau 25h. Lub siab kub flexural lub zog yog kuaj nrog 25mm × 25mm × 125mm qauv, thiab qhov kev kuaj mob yog 3h ntawm 1400 degree hauv huab cua. S-570 scanning electron microscope (SEM) yog siv los soj ntsuam cov cua sov Lub microstructure morphology ntawm qhov tawg ntawm cov qauv ua ntej thiab tom qab kev cuam tshuam.
nyob rau hauv xaus
(1) SiO2 micropowder, -Al2O3 micron Thermal shock stability thiab creep muaj kev cuam tshuam loj tshaj plaws, ua raws li -Al2O3 micropowder thiab silicon micropowder; Qhov kev sim zoo tshaj plaws yog: w ( -Al2O3 micropowder)=11 feem pua , w (SiO2 micropowder)=3 feem pua , firing Ntawm qhov kub ntawm 1650 degree , cov qauv khoom raws li qhov xwm txheej no yog: bulk ntom 2.96g / cm3, porosity 18.5 feem pua, flexural zog poob feem pua 30 feem pua, creep feem pua 0.99 feem pua.
(2) -Al2O3 micropowder, SiO2 micropowder thiab hluav taws kub kub yuav muaj kev cuam tshuam ntau dua rau lub xeev kev sib txuas ntawm cov khoom thiab cov matrix, nrog rau cov mullite, pores thiab residual -Al2O3 hauv matrix, uas yuav muaj kev cuam tshuam ntau dua rau thermal expansion coefficient, elastic modulus thiab thermal conductivity kuj muaj kev cuam tshuam, uas thaum kawg cuam tshuam cov thermal shock tsis kam ntawm cov khoom.
(3) Qhov tawg ntawm corundum mullite cov khoom ntawm chav tsev kub yog tswj los ntawm cov txheej txheem tawg, thaum nyob rau hauv qhov kub thiab txias nws yog tswj los ntawm creep mechanism.
