Mullite tuaj nyob rau hauv ob daim ntawv crystalline

Kev tsim cov ntaub ntawv mullite feem ntau tuaj yeem ua los ntawm kaolinite, sillimanite pab pawg cov zaub mov, aluminium hydroxide lossis aluminium oxide thiab silicon dioxide ncaj qha ua ke. Cov ntaub ntawv av nplaum hnov ​​​​mob nrog alumina lossis sillimanite cov zaub mov nrog kev lag luam alumina nyob rau hauv cov cua kub kom tsim thawj thiab theem nrab mullite. Thaum mullite yog tsim nyob rau hauv thaj tsam ntawm 1000 ~ 1200 ° C, ntxiv qhov kub thiab txias tsuas yog nce crystallization. Kev tsim ntawm theem nrab mullite feem ntau xaus ntawm 1650 degree . Txhawm rau tsim cov khoom lag luam ntom ntom, cov txheej txheem ob-kauj ruam sintering feem ntau yog siv.
Mullite tuaj nyob rau hauv ob daim ntawv crystalline: acicular thiab prismatic. Lub refractoriness ntawm acicular mullite yog siab dua li ntawm prismatic mullite thaum cov tshuaj muaj pes tsawg leeg ntawm acicular mullite yog tib yam. Kaolinite yog rhuab mus rau ntau tshaj 1400 degree C los tsim acicular mullite. Txwv tsis pub, qeeb cua sov mus rau qhov kub qis dua ua prismatic mullite. Tseem muaj cov lus ceeb toom ntawm tubular thiab spherical mullite, qhov qub yog suav tias yog vim yog cov silica thiab alumina tetrahedral loj tsis sib haum ua rau qhov nro tshwm sim los ntawm tubular puab, tom kawg yog hu ua nitrogenous mullite. Cov yam ntxwv ntawm mullite thermal expansion anisotropy ua rau nws muaj thermal stability zoo. Thaum cov khoom siv mullite siab heev yog siv los ua cov khoom noj khoom haus, nws tuaj yeem hloov ncaj qha mus rau lub feeder khiav yam tsis muaj preheating.