INFLUENCE ntawm Pre-SINTERING kub ntawm cov ntxhib ANDALUSITE PARTICLES ntawm thermal SHOCK RESISTANCE ntawm MULLITE-CORUNDUM khoom

Cov qauv siv lead ua ntawm andalusite (Al₂O₃·SiO₂) belongs rau lub orthorhombic system, thiab thermal expansion coefficient ntawm nws cov hais yog yam ntxwv los ntawm anisotropy. Thaum kub kub, nws irreversibly transforms mus rau hauv mullite thiab SiO₂-nplua nuj iav theem, thiab nws thermal expansion coefficient hloov raws li. Thaum lub sij hawm txheej txheem mulliteization, cov siv lead ua axis yuav hloov thiab ua ntev columnar mullite crystals. Cov microcracks tshwm sim los ntawm qhov tsis sib haum ntawm thermal expansion coefficients hauv cov qauv yuav cuam tshuam rau thermal shock resistance ntawm cov qauv, thiab pre-sintering ntawm andalusite hais tuaj yeem txo cov nyhuv saum toj no.
Hloov cov kub kub ua ntej tuaj yeem tswj cov qib ntawm mulliteization, thiab thermal expansion coefficient ntawm qee cov mullite ntxhib hais kuj yuav hloov, uas yuav cuam tshuam rau thermal expansion coefficient sib txawv ntawm coarse andalusite hais thiab matrix, yog li cuam tshuam rau thermal shock resistance. ntawm tus qauv. Hauv kev ua haujlwm no, 20 feem pua ​​(w) coarse andalusite hais (granularity ntawm 5-3 mm) ua ntej raug rho tawm haujlwm ntawm 1300-1600 degree tau ntxiv rau mullite-corundum refractory los tshawb txog cov nyhuv ntawm andalusite pre-sintering kub. Nyob rau ntawm cov nyhuv ntawm tawg loj tau kawm, thiab cov nyhuv ntawm pre-sintering kub ntawm thermal shock tsis kam ntawm mullite-corundum refractory tau kawm.
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1.1 Cov khoom siv raw
The raw materials are: South African andalusite coarse particles without pre-sintering and pre-sintering at 1300, 1400, 1500, 1600 ℃ for 3 hours, the particle size is 5~3mm, w(Al₂O₃)>57%, w(SiO₂)≈40 %; sintered mullite particles, particle size 3~1 and ≤1mm, w(Al₂O₃)≈69%; tabular corundum powder, w(Al₂O₃)>98%, particle size ≤0.044mm (325 mesh); active oxidation Aluminum powder, w(Al₂O₃)>99%, particle size ≤0.044mm (325 mesh); SiO₂ micropowder, w(SiO₂)>95 feem pua, particle loj d50=100nm Tsawg dua los yog sib npaug rau . Lub binder yog pulp pov tseg kua.
1.2 Kev npaj ua qauv
Cov qauv qauv (w) yog: 5 ~ 3mm andalusite aggregate (tsis yog pre-fired lossis pre-fired ntawm qhov sib txawv kub) 20 feem pua ​​, 3-1 thiab Tsawg dua los yog sib npaug rau 1mm mullite aggregate 2{ {11}} feem pua ​​​​txhua tus, Tsawg dua lossis sib npaug li 0.044mm Cov hmoov corundum tabular yog 31 feem pua, cov activated alumina hmoov Tsawg dua los yog sib npaug rau 0.044mm yog 6 feem pua, thiab SiO₂ micropowder yog 3 feem pua. Nyhav andalusite thiab mullite aggregates raws li qhov proportions, thiab sib tov tag nrho cov hmoov zoo (tabular corundum, activated alumina thiab SiO₂ micropowder) hnyav ua ke thiab muab tso rau hauv lub pob zeb rau pre-mixing rau 2 teev. Ua ntej ntxiv cov sib xyaw rau hauv lub tov khoom thiab sib tov nrog cov kua txiv hmab txiv ntoo rau 3 feeb, tom qab ntawd ntxiv cov hmoov premixed thiab sib tov rau 15 feeb. Cov av sib xyaw ua ke yog nias rau hauv cov qauv ntev ntawm 25mm × 25mm × 125mm nrog cov pwm steel ntawm lub tshuab ntsuas siab ntawm lub siab ntawm 200MPa. Tom qab ziab ntawm 110 degree rau 24h, nws tau muab tso rau hauv qhov cub hluav taws xob thiab khaws cia ntawm 1450 degree rau 3h. raug rho tawm haujlwm.
Tsis tas li ntawd, cov hmoov zoo ntawm cov mis yog coj mus rau batching, thiab cov qauv matrix yog tsim los ntawm kev sib xyaw, molding thiab firing tib yam li saum toj no, uas yog siv rau thermal expansion test.
1.3 Kev Ntsuas Kev Ua Haujlwm
Cov theem muaj pes tsawg leeg ntawm andalusite hais tom qab kev kub hnyiab tau soj ntsuam los ntawm BRUKERD8Focus × ​​diffraction analyzer, lub scanning ntau yog 10 degree ~ 70 degree, qhov voltage yog 40kV, tam sim no yog 30mA, thiab cov kauj ruam loj yog 0.02 degree; raws li GB/T7320-2008, calcination tau ntsuas los ntawm txoj kev ejector pas nrig. Thermal expansion ntawm post-matrix qauv ntawm 25-950 degree . Raws li GB/T2997-2000, qhov ntau ntom thiab pom meej porosity ntawm cov qauv tom qab hlawv raug kuaj, cov kab hloov pauv tom qab hlawv raug kuaj raws li GB/T5988-2007, lub zog flexural ntawm chav tsev kub yog kuaj raws li GB/T{13}}, thiab lub zog flexural nyob rau hauv chav tsev kub yog kuaj raws li YB/T376.2 Nyob rau hauv 1995, lub thermal shock tsis kam ntawm cov qauv raug rho tawm haujlwm raug kuaj (tus cwj pwm los ntawm kev tuav tus nqi ntawm flexural lub zog tom qab 5 zaug ntawm huab cua-txias thermal shocks ntawm 950 degree ), thiab cov elastic modulus tau ntsuas los ntawm ib txwm kub elastic modulus tester (DEMA-01); ZEISSLICMA scanning electron microscope soj ntsuam cov microstructure ntawm cov qauv raug rho tawm haujlwm. Cov qauv yuav tsum tau kho nrog cov resin ua ntej kuaj, thiab tom qab ntawd corroded los ntawm hydrofluoric acid rau 15s thiab tom qab ntawd txau nrog kub.
Cov txiaj ntsig thiab kev sib tham
2.1 Phase tsom xam ntawm andalusite coarse hais tom qab calcination
Tom qab calcination ntawm 1300 degree, cov theem tseem ceeb yog andalusite thiab me me ntawm quartz, qhia tias mullite tseem tsis tau pib; Ib feem ntawm nws yog mullite; Nws yog tag nrho cov mullite tom qab pre-sintering ntawm 1600 degree, qhia tias nws tau tag nrho cov mullite. Nws tuaj yeem pom tias cov ntsiab lus seem ntawm andalusite nyob rau hauv qhov sib sau ua ke tom qab ua ntej sintering txo qis nrog qhov nce ntawm pre-sintering kub, thiab qhov hloov pauv ntawm mullite ntawm andalusite nce nrog qhov nce ntawm pre-sintering kub.
2.2 Lub cev muaj zog ntawm cov qauv
Nrog rau qhov nce ntawm pre-sintering kub ntawm coarse andalusite hais, qhov nthuav ntawm tus qauv txo qis kom txog thaum nws shrinks. Andalusite hloov mus rau hauv mullite thiab SiO2-nplua nuj iav theem thaum lub sij hawm ua ntej sintering txheej txheem, thiab nrog kev nce ntawm pre-sintering kub, lub degree ntawm mulliteization ntawm andalusite nce, thiab SiO2-nplua nuj iav theem kuj nce; nyob rau hauv mullite-corundum Thaum lub sij hawm sintering txheej txheem ntawm cov qauv, cov residual andalusite yuav mus ntxiv mus rau mullite. Ntawm qhov tod tes, nrog rau qhov nce ntawm andalusite pre-sintering kub, tus nqi ntawm cov seem andalusite poob, yog li lub ntim expansion ntawm ntxhib andalusite hais txuas mus rau mullite thaum lub sij hawm sintering txheej txheem ntawm cov qauv maj mam txo; Nrog rau qhov nce ntawm qhov kub ntawm sintering, SiO2- theem iav nplua nuj nce, kom cov nyhuv ntawm cov kua theem los txhawb sintering yog maj mam ntxiv dag zog. Raws li ob qho laj thawj no, cov qauv raug rho tawm haujlwm hloov pauv los ntawm kev nthuav dav mus rau kev cog lus nrog qhov nce ntawm qhov kub hnyiab ua ntej ntawm coarse andalusite hais.
Nrog rau qhov nce ntawm andalusite calcination kub, lub elastic modulus ntawm calcined kuaj tau nce tsis tu ncua, los ntawm 20.23GPa nrog uncalcined andalusite mus rau 36.98GPa nrog 1600 degree calcined andalusite. Nrog rau qhov nce ntawm pre-sintering kub, qhov degree ntawm mulliteization ntawm ntxhib andalusite hais nce, qhov sib txawv ntawm thermal expansion coefficient ntawm aggregate thiab matrix txo, thiab qhov luaj li cas ntawm microcracks tshwm sim los ntawm thermal expansion coefficient mismatch txo qis. Lub elastic modulus ntawm andalusite nce nrog ntxiv ntawm andalusite pre-sintering kub.
Nrog rau qhov nce ntawm pre-sintering kub ntawm andalusite, lub zog flexural ntawm chav tsev kub ntawm cov qauv raug rho tawm haujlwm maj mam nce, tab sis lub zog tuav tus nqi txo qis tom qab raug cua txias thermal shocks ntawm 950 degree rau 5 zaug. Qhov no tej zaum yuav yog vim hais tias nrog qhov nce ntawm pre-sintering kub, lub degree ntawm mulliteization ntawm andalusite nce, thiab qhov sib txawv ntawm thermal expansion coefficient ntawm aggregate thiab matrix txo. Thaum lub sij hawm sintering thiab txias, thermal expansion coefficient ntawm aggregate thiab matrix yog mismatched. Qhov luaj li cas ntawm micro-cracks kuj maj mam txo, thaum lub me me-me me micro-cracks tsis tuaj yeem ua lub luag haujlwm hauv kev txo cov kev ntxhov siab thermal, tiv thaiv cov kab nrib pleb tshiab thiab tawg tawm thaum lub sij hawm thermal shock, uas ua rau maj mam txo qis hauv thermal shock. tsis kam ntawm tus qauv. . Yog li ntawd, piv nrog rau ntxiv cov khoom ua ntej raug rho tawm haujlwm andalusite cov khoom loj, cov mullite-corundum refractory nrog unpre-fired andalusite coarse hais (5 ~ 3mm) muaj zoo thermal shock resistance.