Kaya zinyalala zenizeni za electroceramics zitha kugwiritsidwa ntchito kupanga mullite ceramics?

Zinyalala zina zamafakitale zikuwonetsedwa kuti ndizothandiza popanga zinthu zadothi za mullite. Zinyalala zamafakitalezi zimakhala ndi zitsulo zina zachitsulo monga silika (SiO2) ndi alumina (Al2O3). Izi zimapereka zinyalala zomwe zitha kugwiritsidwa ntchito ngati gwero lazinthu zoyambira pokonzekera mullite ceramics. Cholinga cha pepala lounikirali ndikuphatikiza ndikuwunikanso njira zosiyanasiyana zokonzekera zoumba za mullite zomwe zidagwiritsa ntchito zinyalala zosiyanasiyana zamakampani ngati zida zoyambira. Ndemangayi ikufotokozanso kutentha kwa sintering ndi zowonjezera za mankhwala zomwe zimagwiritsidwa ntchito pokonzekera ndi zotsatira zake. Kuyerekeza kwa mphamvu zamakina komanso kukulitsa kwamafuta azinthu zoumba mullite zomwe zakonzedwa kuchokera ku zinyalala zosiyanasiyana za mafakitale zidayankhidwanso pantchitoyi.

Mullite, yomwe nthawi zambiri imatchedwa 3Al2O3∙2SiO2, ndi chinthu chabwino kwambiri cha ceramic chifukwa cha mawonekedwe ake odabwitsa. Ili ndi malo osungunuka kwambiri, otsika kwambiri pakukulitsa kwamafuta, mphamvu yayikulu pakutentha kwambiri, ndipo imakhala ndi kugwedezeka kwamafuta komanso kukana kukwawa [1]. Matenthedwe odabwitsawa komanso makina amakinawa amathandizira kuti zinthuzo zizigwiritsidwa ntchito ngati zotchingira, mipando yamoto, ma substrates for catalytic converters, machubu ang'anjo, ndi zishango za kutentha.

Mullite imapezeka ngati mchere wosowa ku Mull Island, Scotland [2]. Chifukwa chosowa m'chilengedwe, zoumba zonse za mullite zomwe zimagwiritsidwa ntchito m'makampani zimapangidwa ndi anthu. Kafukufuku wambiri wachitika pokonzekera zoumba za mullite pogwiritsa ntchito ma precursors osiyanasiyana, kuyambira kumafakitale / ma labotale giredi [3] kapena mwachilengedwe mchere wa aluminosilicate [4]. Komabe, mtengo wa zida zoyambirazi ndi zokwera mtengo, zomwe zimapangidwira kapena kukumbidwa kale. Kwa zaka zambiri, ofufuza akhala akuyang'ana njira zina zachuma zopangira mullite ceramics. Chifukwa chake, zoyambira zambiri za mullite zochokera ku zinyalala zamafakitale zafotokozedwa m'mabuku. Zinyalala za m'mafakitalezi zimakhala ndi silika ndi aluminiyamu zothandiza kwambiri, zomwe ndi mankhwala ofunikira kuti apange matope a mullite. Ubwino wina wogwiritsa ntchito zinyalala zam'mafakitalezi ndi kupulumutsa mphamvu ndi mtengo ngati zinyalalazo zidapatutsidwa ndikugwiritsidwanso ntchito ngati zida zauinjiniya. Kuphatikiza apo, izi zitha kuthandizanso kuchepetsa zovuta zachilengedwe ndikukulitsa phindu lake pazachuma.

Pofuna kufufuza ngati zinyalala zenizeni za electroceramics zitha kugwiritsidwa ntchito popanga zoumba mullite, zinyalala zenizeni za electroceramics zosakanizidwa ndi alumina ufa ndi zinyalala zenizeni za electroceramics monga zopangira zidayerekezedwa. Makhalidwe a mullite ceramic adafufuzidwa. XRD ndi SEM adagwiritsidwa ntchito pophunzira kapangidwe ka gawo ndi microstructure.

Zotsatira zikuwonetsa kuti zomwe zili mu mullite zimachulukitsidwa ndikukweza kutentha kwa sintering, ndipo nthawi yomweyo kuchuluka kwachulukidwe kumachulukira. Zopangira ndi zinyalala zenizeni za electroceramics, motero ntchito ya sintering ndi yayikulu, ndipo njira ya sintering imatha kuchulukitsidwa, komanso kachulukidwe kawo kachulukidwenso. Mullite ikangokonzedwa ndi zinyalala za electroceramics, kuchulukirachulukira komanso mphamvu zopondereza zimakhala zazikulu, porosity ndi yaying'ono kwambiri, ndipo mawonekedwe athunthu amakhala abwino kwambiri.

Motsogozedwa ndi kufunikira kwa njira zotsika mtengo komanso zowononga zachilengedwe, zoyeserera zambiri zagwiritsa ntchito zinyalala zosiyanasiyana zamafakitale monga zida zoyambira kupanga mullite ceramics. Njira zopangira, kutentha kwa sintering, ndi zowonjezera za mankhwala zawunikiridwa. Njira yachikhalidwe yopangira njira yomwe imaphatikizapo kusakaniza, kukanikiza, ndi kuchitapo kanthu kwa mullite precursor inali njira yomwe imagwiritsidwa ntchito kwambiri chifukwa cha kuphweka kwake komanso mtengo wake. Ngakhale njira iyi imatha kupanga porous mullite ceramics, zowoneka bwino za mullite ceramic zomwe zimatsatira zidanenedwa kukhala zosachepera 50%. Kumbali ina, kuzizira kozizira kunawonetsedwa kuti kumatha kupanga porous mullite ceramic, yokhala ndi porosity yowoneka bwino ya 67%, ngakhale kutentha kwambiri kwa 1500 ° C. Ndemanga ya kutentha kwa sintering ndi zina zowonjezera mankhwala zomwe zimagwiritsidwa ntchito popanga mullite zidachitika. Ndikofunikira kugwiritsa ntchito kutentha kwa sintering pamwamba pa 1500 ° C popanga mullite, chifukwa cha kuchuluka kwa zomwe zimachitika pakati pa Al2O3 ndi SiO2 mu kalambulabwalo. Komabe, zinthu zambiri za silika zomwe zimagwirizanitsidwa ndi zonyansa zomwe zili mu kalambulabwalo zingayambitse kusinthika kwachitsanzo kapena kusungunuka panthawi yotentha kwambiri. Ponena za mankhwala owonjezera, CaF2, H3BO3, Na2SO4, TiO2, AlF3, ndi MoO3 adanenedwa ngati chithandizo chothandizira kuchepetsa kutentha kwa sintering pamene V2O5, Y2O3-doped ZrO2 ndi 3Y-PSZ angagwiritsidwe ntchito kulimbikitsa kachulukidwe kwa mullite ceramics. Doping ndi zowonjezera mankhwala monga AlF3, Na2SO4, NaH2PO4 · 2H2O, V2O5, ndi MgO anathandiza kukula anisotropic wa masharubu mullite, amene pambuyo kulimbikitsa mphamvu thupi ndi kulimba kwa mullite ceramics.