Zirconia bricks rau cov ntaub ntawv tshwj xeeb qib refractory
Los ntawm kev siv cov zirconia thiab alumina ua raw cov ntaub ntawv, kev sib tsoo ultrafine, nruj particle loj tswj, thiab cov txheej txheem pa, siab - lub zog thiab siab toughness zirconia alumina puas ceramics tuaj yeem tsim. Qhov zirconia cib no yog cov khoom siv tshwj xeeb qib refractory.
Cov txiaj ntsig kev tshawb fawb qhia tau hais tias ntxiv alumina rau zirconia matrix tuaj yeem cuam tshuam kev loj hlob ntawm zirconia nplej, uas muaj txiaj ntsig zoo rau lub neej ntawm metastable tetragonal zirconia nplej, yog li txhim kho lub zog thiab tawg toughness ntawm cov khoom. Thaum cov feem loj ntawm alumina yog 20%, lub zog flexural ntawm cov ceramics ncav cuag 676.7MPa, thiab cov pob txha tawv tawv ncav cuag 10MPa / m ². Kev sib xyaw ua ke ntawm theem hloov pauv toughening thiab particle dispersion toughening txhim kho cov khoom siv hluav taws xob ntawm cov khoom siv ceramic.
Kev npaj ntawm alumina micro hmoov los ntawm thermal decomposition txoj kev, kev npaj ntawm zirconia ultrafine hmoov los ntawm cov tshuaj co los nag txoj kev, thiab kev npaj ntawm zirconia / alumina puas ceramics los ntawm cov txheej txheem tsim nyog. Nws ntseeg tau tias ntxiv alumina tuaj yeem cuam tshuam kev loj hlob ntawm zirconia nplej thiab txhim kho lub zog thiab tawv ntawm matrix. Thaum cov feem loj ntawm alumina nce mus txog 30%, lub zog flexural ntawm nag hmo cov ceramics raug rho tawm haujlwm ntawm 1600℃yog 968MPa, thiab pob txha toughness yog 13.7MPa / cm².
Ntxiv zirconia rau corundum refractory cov ntaub ntawv los tsim jade zirconia cov ntaub ntawv yog ib qho piv txwv ntawm daim ntawv thov ntawm theem transformation ntxiv dag zog rau, toughening, thiab microcrack toughening theories nyob rau hauv cov ntaub ntawv refractory. Thaum lub sij hawm ua kom txias ntawm cov qauv corundum zirconia, zirconia tau hloov mus rau theem, tsim qee tus lej ntawm microcracks hauv cov khoom, uas muaj txiaj ntsig zoo rau kev txhim kho lub zog thiab tawv ntawm cov khoom. Thaum cov zirconia ntxiv me me, tus naj npawb ntawm microcracks hauv cov khoom tsis tseem ceeb, uas tsis tshua muaj kev cuam tshuam rau lub zog ntawm corundum refractory cov ntaub ntawv; Thaum cov nyiaj sab nraud yog siab dhau (xws li ncav cuag ib feem ntawm 9% lossis ntau dua), vim muaj cov microcracks ntau hauv cov khoom, lub zog flexural ntawm cov khoom txo qis.
Siv corundum, hluavtaws mullite, thiab monoclinic zirconia ua raw cov ntaub ntawv, qhov sib tov yog tsim los ntawm isostatic nias thiab raug rho tawm haujlwm ntawm 1650-1700 degree. Txoj cai ntawm kev hloov pauv ntawm qhov kub thiab txias ntawm lub zog flexural ntawm cov qauv yog tias lub zog ua ntej nce nrog qhov kub thiab txias kom txog thaum hloov pauv kub, thiab tom qab ntawd txo qis nrog qhov kub thiab txias. Qhov no yog vim lub thermal expansion mismatch ntawm txawv siv lead ua theem thiab lub zos bridging ntawm microcracks. Kev hloov pauv kub yog nyob nruab nrab ntawm 800-900 degree, thiab vim yog kev hloov pauv martensitic ntawm zirconia, muaj "khiav" yam ntxwv ntawm 1000-1200 degree, nrog lub hav hauv qab ntawm 1100 degree.
