Silicon carbide (SiC) ufa wa ceramicali ndi ubwino wa mphamvu ya kutentha kwapamwamba, kukana kwa okosijeni wabwino, kukana kuvala kwambiri ndi kukhazikika kwa kutentha, kuwonjezereka kwazing'ono kwa kutentha, kutentha kwapamwamba, kukhazikika kwa mankhwala, ndi zina zotero. zida, zigamba zosagwirizana ndi kutentha, zida za injini za ndege, zombo zamakhemikhali, machubu osinthira kutentha ndi zida zina zamakina pamikhalidwe yovuta, ndipo ndi zida zaukadaulo zomwe zimagwiritsidwa ntchito kwambiri.Sizimangogwira ntchito yofunika kwambiri m'magawo apamwamba kwambiri omwe akutukuka (monga injini za ceramic, mlengalenga, ndi zina zotero), komanso ali ndi msika wotakata ndi malo ogwiritsira ntchito kuti apangidwe mu mphamvu zamakono, zitsulo, makina, zipangizo zomangira. , makampani opanga mankhwala ndi madera ena.

Njira zokonzekera zasilicon carbide ufaakhoza kugawidwa makamaka m'magulu atatu: njira yolimba, njira yamadzimadzi ndi njira ya gasi.

1. Njira yokhazikika

Njira yolimba yagawo imaphatikizapo njira yochepetsera carbothermal ndi njira ya silicon carbon direct reaction.Njira zochepetsera Carbothermal zimaphatikizansopo njira ya Acheson, njira ya ng'anjo yowongoka komanso njira yosinthira kutentha kwambiri.Silicon carbide ufaKukonzekera poyamba kunakonzedwa ndi njira ya Acheson, pogwiritsa ntchito coke kuchepetsa silicon dioxide pa kutentha kwakukulu (pafupifupi 2400 ℃), koma ufa wopezedwa ndi njirayi uli ndi kukula kwakukulu kwa tinthu (> 1mm), umadya mphamvu zambiri, ndipo ndondomekoyi ndi zovuta.M'zaka za m'ma 1980, zida zatsopano zopangira ufa wa β-SiC, monga ng'anjo yowongoka komanso chosinthira kutentha kwambiri, zidawonekera.Monga wogwira mtima komanso wapadera polima pakati pa mayikirowevu ndi zinthu za mankhwala mu olimba wakhala pang'onopang'ono kumveka, luso synthesizing sic ufa ndi mayikirowevu Kutenthetsa wakula kwambiri.Njira ya silicon carbon direct reaction imaphatikizansopo kudziletsa kutulutsa kutentha kwakukulu (SHS) ndi njira yopangira mawotchi.Njira yochepetsera ya SHS imagwiritsa ntchito momwe kutentha kwapakati pa SiO2 ndi Mg kupangira kusowa kwa kutentha.Thesilicon carbide ufazopezedwa ndi njira imeneyi ndi mkulu chiyero ndi yaing'ono tinthu kukula, koma Mg mu mankhwala ayenera kuchotsedwa wotsatira njira monga pickling.

2 njira yamadzimadzi

The madzi gawo njira makamaka zikuphatikizapo Sol-gel osakaniza njira ndi polima matenthedwe kuwola njira.Sol-gel osakaniza njira ndi njira kukonzekera gel osakaniza munali Si ndi C ndi yoyenera sol-gel osakaniza ndondomeko, ndiyeno pyrolysis ndi mkulu kutentha carbothermal kuchepetsa kupeza pakachitsulo carbide.High kutentha kuwonongeka kwa organic polima ndi luso luso yokonza pakachitsulo carbide: mmodzi ndi kutentha gel osakaniza polysiloxane, kuwola anachita kumasula monomers ang'onoang'ono, ndipo potsiriza kupanga SiO2 ndi C, ndiyeno ndi mpweya kuchepetsa anachita kubala SiC ufa;Zina ndikutenthetsa polysilane kapena polycarbosilane kuti amasule ma monomers ang'onoang'ono kuti apange chigoba, kenako kupanga.silicon carbide ufa.

3 Njira ya gasi

Pakali pano, gasi gawo synthesis wasilicon carbideceramic ultrafine ufa makamaka amagwiritsa ntchito gas phase deposition (CVD), Plasma Induced CVD, Laser Induced CVD ndi matekinoloje ena kuti awole zinthu zamoyo pa kutentha kwakukulu.The analandira ufa ali ndi ubwino mkulu chiyero, yaing'ono tinthu kukula, zochepa tinthu agglomeration ndi kulamulira mosavuta zigawo zikuluzikulu.Ndi njira yapamwamba kwambiri pakali pano, koma ndi mtengo wapatali komanso zokolola zochepa, sizovuta kukwaniritsa kupanga kwakukulu, ndipo ndizoyenera kupanga zipangizo za laboratory ndi mankhwala omwe ali ndi zofunikira zapadera.

Pakali pano, asilicon carbide ufantchito makamaka submicron kapena ngakhale nano mlingo ufa, chifukwa tinthu kukula tinthu ndi yaing'ono, mkulu pamwamba ntchito, choncho vuto lalikulu ndi kuti ufa n'zosavuta kutulutsa agglomeration, m'pofunika kusintha pamwamba pa ufa kuteteza kapena ziletsa. agglomeration yachiwiri ya ufa.Pakali pano, njira kubalalitsidwa kwa SiC ufa makamaka zikuphatikizapo magulu otsatirawa: mkulu-mphamvu pamwamba kusinthidwa, kutsuka, dispersant mankhwala a ufa, inorganic ❖ kuyanika kusinthidwa, organic ❖ kuyanika kusinthidwa.