Ingaba inkunkuma ye-electroceramics emsulwa ingasetyenziselwa ukwenza iiseramikhi ze-mullite?

Eminye inkunkuma yemizi-mveliso iboniswa iluncedo kwimveliso yeeseramikhi ze-mullite. Ezi nkunkuma zamashishini zizityebi kwii-oxide zetsimbi ezithile ezifana ne-silica (SiO2) kunye ne-alumina (Al2O3). Oku kunika inkunkuma amandla okuba isetyenziswe njengomthombo wemathiriyeli wokuqala wokulungiswa kweeseramikhi ze-mullite. Injongo yeli phepha lophononongo kukuqulunqa nokuphonononga iindlela ezahlukeneyo zokulungisa iiseramikhi ezisebenzise iintlobo ngeentlobo zenkunkuma yamashishini njengemathiriyeli yokuqala. Olu phononongo lukwachaza amaqondo obushushu e-sintering kunye nezongezo zekhemikhali ezisetyenziswa ekulungiseleleni kunye neziphumo zayo. Uthelekiso lwamandla oomatshini kunye nokwandiswa kobushushu bekeramikhi exeliweyo yemullite elungiswe kwinkunkuma eyahlukeneyo yemizi-mveliso nayo yaqwalaselwa kulo msebenzi.

I-Mullite, edla ngokuchazwa njenge-3Al2O3∙2SiO2, yimathiriyeli egqwesileyo yeceramic ngenxa yeempawu zayo ezingaqhelekanga. Inendawo yokunyibilika ephezulu, i-coefficient ephantsi yokwandiswa kwe-thermal, amandla aphezulu kumaqondo obushushu aphezulu, kwaye inokothuka kwe-thermal kunye nokuxhathisa kwe-creep [1]. Ezi mpawu zingaqhelekanga zokushisa kunye nomatshini zenza ukuba izinto zisetyenziswe kwizicelo ezifana ne-refractories, ifenitshala ye-kiln, i-substrates ye-catalytic converters, iityhubhu zomlilo, kunye nezikhuselo zokushisa.

I-Mullite inokufumaneka kuphela njengeminerali enqabileyo e-Mull Island, eScotland [2]. Ngenxa yobukho bayo obunqabileyo kwindalo, zonke iiseramics zemullite ezisetyenziswa kushishino zenziwe ngabantu. Uphando oluninzi lwenziwe ukulungiselela iiseramikhi ze-mullite kusetyenziswa izandulela ezahlukeneyo, kuqalwa ukusuka kwimizi-mveliso/kwibakala lelebhu yeekhemikhali [3] okanye ngokwendalo iminerali eyialuminosilicate [4]. Nangona kunjalo, iindleko zezi zinto zokuqalisa ziyabiza, ezidityanisiweyo okanye zombiwe ngaphambili. Kangangeminyaka, abaphandi bebejonge ezinye iindlela zoqoqosho zokudibanisa i-mullite ceramics. Kungoko, intaphane ye-mullite precursors evela kwinkunkuma yemizi-mveliso iye yaxelwa kuncwadi. Le nkunkuma yemizi-mveliso inomxholo ophezulu we-silica kunye ne-alumina eluncedo, ezizikhompawundi zemichiza ezibalulekileyo ezifunekayo ukuvelisa i-mullite ceramics. Olunye uncedo lokusebenzisa le nkunkuma yemizi-mveliso lumandla kunye nokongiwa kweendleko ukuba inkunkuma iye yajikiswa yaza yasetyenziswa ngokutsha njengemathiriyeli yobunjineli. Ngaphaya koko, oku kunokunceda ukunciphisa umthwalo wokusingqongileyo kunye nokwandisa inzuzo yayo kwezoqoqosho.

Ukuze kuphandwe ukuba ingaba inkunkuma ye-electroceramics emsulwa ingasetyenziselwa ukwenza iiseramikhi ze-mullite, inkunkuma ye-electroceramics esulungekileyo exutywe nomgubo we-alumina kunye nenkunkuma ye-electroceramics esulungekileyo njengoko kuthelekiswa imathiriyeli ekrwada. iipropati ze-mullite ceramic zaphandwa. I-XRD kunye ne-SEM zazisetyenziselwa ukufunda ukubunjwa kwesigaba kunye ne-microstructure.

Iziphumo zibonisa ukuba umxholo we-mullite unyuswa ngokunyusa ubushushu be-sintering, kwaye kwangaxeshanye ukuxinana kobuninzi kuyenyuka. Izixhobo ezikrwada ziyinkunkuma ecocekileyo ye-electroceramics, ke ngoko umsebenzi we-sintering mkhulu, kwaye inkqubo ye-sintering inokukhawuleziswa, kwaye ukuxinana kuyanda. Xa i-mullite ilungiselelwe kuphela yinkunkuma ye-electroceramics, ubuninzi bobuninzi kunye namandla oxinzelelo bukhulu kakhulu, i-porosity incinci, kwaye iimpawu zomzimba ezibanzi ziya kuba zezona zilungileyo.

Iqhutywa yimfuneko yeendleko eziphantsi kunye nezinye iindlela ezihambelana nokusingqongileyo, iinzame ezininzi zophando ziye zasebenzisa inkunkuma eyahlukeneyo yamashishini njengezinto zokuqala zokuvelisa i-mullite ceramics. Iindlela zokulungisa, amaqondo obushushu e-sintering, kunye nezongezo zekhemikhali ziye zaphononongwa. Indlela yemveli yokusetyenzwa kwendlela ebandakanya ukuxuba, ukucofa, kunye nokusabela kwi-intercursor ye-mullite yeyona ndlela ixhaphakileyo ngenxa yobulula bayo kunye nokusebenza kweendleko. Nangona le ndlela ikwazi ukuvelisa i-porous mullite ceramics, ii-porosities zesiphumo se-mullite ceramic kuxelwe ukuba zihlala ngaphantsi kwe-50%. Kwelinye icala, ukugalelwa komkhenkce kubonakaliswe ukuba kukwazi ukuvelisa i-mullite ceramic enombhobho kakhulu, ene-porosity ecacileyo ye-67%, nokuba kubushushu obuphezulu kakhulu be-sintering obuyi-1500 °C. Ukuphononongwa kwamaqondo okushisa e-sintering kunye nezongezo ezahlukeneyo zeekhemikhali ezisetyenziselwa ukuveliswa kwe-mullite zenziwe. Kuyinto enqwenelekayo ukusebenzisa iqondo lobushushu elingaphezulu kwe-1500 °C kwimveliso ye-mullite, ngenxa yezinga eliphezulu lokusabela phakathi kwe-Al2O3 kunye ne-SiO2 kwi-precursor. Nangona kunjalo, umxholo we-silica ogqithisileyo ohambelana nokungcola kwi-precursor unokukhokelela kwisampulu yokuguqulwa okanye ukunyibilika ngexesha lobushushu obuphezulu. Ngokubhekiselele kwizongezo zemichiza, i-CaF2, i-H3BO3, i-Na2SO4, i-TiO2, i-AlF3, kunye ne-MoO3 ziye zaxelwa njengoncedo olusebenzayo ekunciphiseni ukushisa kwe-sintering ngelixa i-V2O5, i-Y2O3-doped ZrO2 kunye ne-3Y-PSZ ingasetyenziselwa ukukhuthaza ukuxinana kwee-ceramics ze-mullite. I-Doping ngezongezo zekhemikhali ezifana ne-AlF3, i-Na2SO4, i-NaH2PO4 · 2H2O, i-V2O5, kunye ne-MgO incedise ukukhula kwe-anisotropic ye-whiskers ye-mullite, eyathi emva koko yaphakamisa amandla omzimba kunye nokuqina kwe-ceramics ye-mullite.