Kutulutsa kwa zotsutsana
Kuyankha koyipasilicon carbide ceramicNjira yopangira zinthu imaphatikizapo kuyika zinthu mu ceramic compacting, sintering flux infiltration agent compacting, reaction sintering ceramic product preparation, silicon carbide wood ceramic preparation ndi zina zotero.
Kamvekedwe ka silicon carbide kamene kamayambitsa kukwiya
Choyamba, 80-90% ya ufa wa ceramic (wopangidwa ndi ufa umodzi kapena iwiri yaufa wa silicon carbidendi ufa wa boron carbide), 3-15% ya ufa wochokera ku carbon (wopangidwa ndi umodzi kapena iwiri ya carbon black ndi phenolic resin) ndi 5-15% ya molding agent (phenolic resin, polyethylene glycol, hydroxymethyl cellulose kapena paraffin) zimasakanizidwa mofanana pogwiritsa ntchito ball mill kuti mupeze ufa wosakanikirana, womwe umaumitsidwa ndi spray ndi granulated, kenako nkukanikiza mu nkhungu kuti mupeze ceramic compact yokhala ndi mawonekedwe osiyanasiyana.
Kachiwiri, ufa wa silicon 60-80%, ufa wa silicon carbide 3-10% ndi ufa wa boron nitride 37-10% zimasakanizidwa mofanana, ndikuzikanikiza mu chikombole kuti zikhale zofewa zolowa m'madzi.
Chopondapo cha ceramic ndi chopondapo cha sintered infiltrant kenako zimayikidwa pamodzi, ndipo kutentha kumakwezedwa kufika pa 1450-1750℃ mu uvuni wa vacuum wokhala ndi vacuum digiri yosachepera 5×10-1 Pa kuti ziwotchedwe ndi kusungidwa kutentha kwa maola 1-3 kuti zipeze zotsatira za chinthu cha ceramic chopondapo. Zotsalira za infiltrant pamwamba pa ceramic yopondapo zimachotsedwa pogogoda kuti papezeke pepala lolimba la ceramic, ndipo mawonekedwe oyambirira a chopondapo amasungidwa.
Pomaliza, njira yosinthira zinthu imatengedwa, kutanthauza kuti, silicon yamadzimadzi kapena silicon alloy yokhala ndi ntchito yochitapo kanthu pa kutentha kwambiri imalowa mu ceramic blank yokhala ndi kaboni mothandizidwa ndi mphamvu ya capillary, ndipo imachitapo kanthu ndi kaboni momwemo kuti ipange silicon carbide, yomwe imakula kwambiri, ndipo ma pores otsalawo amadzazidwa ndi silicon yoyambira. Porous ceramic blank ikhoza kukhala carbon yeniyeni kapena silicon carbide/carbon-based composite material. Yoyamba imapezeka pokonza ndi kuwotcha utomoni wachilengedwe, pore former ndi solvent. Yomalizayi imapezeka pokonza tinthu ta silicon carbide/resin-based composite materials kuti ipeze silicon carbide/carbon-based composite materials, kapena pogwiritsa ntchito α-SiC ndi carbon powder ngati zinthu zoyambira ndikugwiritsa ntchito njira yokanikiza kapena yopangira jekeseni kuti mupeze zinthu zophatikiza.
Kupopera kosapanikizika
Njira yochepetsera kupanikizika ya silicon carbide ingagawidwe m'magulu awiri: solid-phase sintering ndi liquid-phase sintering. M'zaka zaposachedwapa, kafukufuku wazoumbaumba za silicon carbideKwathu ndi kunja kwa dziko lakhala likuyang'ana kwambiri pa kupopera kwa madzi. Njira yokonzekera ceramic ndi iyi: kupopera mpira pogwiritsa ntchito zinthu zosiyanasiyana–>kupopera ndi kupopera–>kukanikiza mouma–>kulimbitsa thupi lobiriwira–>kupopera vacuum.
Zogulitsa za silikoni zosasunthika zopanda mphamvu
Onjezani magawo 96-99 a ufa wa silicon carbide ultrafine (50-500nm), magawo 1-2 a ufa wa boron carbide ultrafine (50-500nm), magawo 0.2-1 a nano-titanium boride (30-80nm), magawo 10-20 a phenolic resin yosungunuka m'madzi, ndi magawo 0.1-0.5 a dispersant yogwira ntchito bwino kwambiri ku mphero ya mpira kuti mugaye ndikusakaniza kwa maola 24, ndikuyika slurry yosakaniza mu mbiya yosakaniza kuti musakanize kwa maola awiri kuti muchotse thovu mu slurry.
Chosakaniza chomwe chili pamwambapa chimapopera mu nsanja ya granulation, ndipo ufa wa granulation wokhala ndi mawonekedwe abwino a tinthu tating'onoting'ono, kusinthasintha kwabwino, kufalikira kwa tinthu tating'onoting'ono komanso chinyezi chochepa zimapezeka powongolera kuthamanga kwa kupopera, kutentha kwa kulowa kwa mpweya, kutentha kwa kutuluka kwa mpweya ndi kukula kwa tinthu ta pepala lopopera. Kusintha kwa ma centrifugal frequency ndi 26-32, kutentha kwa kulowa kwa mpweya ndi 250-280℃, kutentha kwa kutuluka kwa mpweya ndi 100-120℃, ndipo kuthamanga kwa kulowa kwa slurry ndi 40-60.
Ufa wa granulation womwe uli pamwambapa umayikidwa mu chikombole cha carbide chopangidwa ndi simenti kuti usindikizidwe kuti upeze thupi lobiriwira. Njira yokanikiza ndi kupanikizika kwa mbali zonse ziwiri, ndipo kupanikizika kwa zida zamakina ndi matani 150-200.
Thupi lobiriwira losindikizidwa limayikidwa mu uvuni woumitsira kuti liume ndi kukonzedwa kuti likhale lobiriwira komanso lolimba bwino.
Thupi lobiriwira lokonzedwa pamwambapa limayikidwa muchophikira cha graphitendipo imakonzedwa bwino komanso mosamala, kenako chophimbira cha graphite chokhala ndi thupi lobiriwira chimayikidwa mu uvuni wotentha kwambiri wa vacuum kuti chiwotchedwe. Kutentha kwa kuwombera ndi 2200-2250℃, ndipo nthawi yotenthetsera ndi maola 1-2. Pomaliza, ziwiya za silicon carbide zopanda mphamvu zambiri zimapezeka.
Kuchotsa gawo lolimba
Njira yochepetsera kupanikizika ya silicon carbide ingagawidwe m'magulu awiri: solid-phase sintering ndi liquid-phase sintering. Liquid-phase sintering imafuna kuwonjezera zowonjezera za sintering, monga Y2O3 binary ndi ternary zowonjezera, kuti SiC ndi zinthu zake zophatikizika zikhale ndi sintering ya liquid-phase ndikupeza kukhuthala pa kutentha kochepa. Njira yokonzekera ma ceramics a silicon carbide opangidwa ndi solid-phase sintering imaphatikizapo kusakaniza zinthu zopangira, kupopera, kupanga, ndi vacuum sintering. Njira yeniyeni yopangira ndi iyi:
70-90% ya submicron α silicon carbide (200-500nm), 0.1-5% ya boron carbide, 4-20% ya resin, ndi 5-20% ya organic binder zimayikidwa mu chosakanizira ndikuwonjezeredwa ndi madzi oyera kuti zisakanizidwe monyowa. Pambuyo pa maola 6-48, slurry yosakanikirana imadutsa mu sefa ya 60-120 mesh;
Dothi losefedwa limasefedwa kudzera mu nsanja yopopera. Kutentha kwa malo olowera mu nsanja yopopera ndi 180-260℃, ndipo kutentha kwa malo otulutsira ndi 60-120℃; kuchuluka kwa zinthu zopukutidwa ndi 0.85-0.92g/cm3, kusinthasintha kwa madzi ndi 8-11s/30g; zinthu zopukutidwa zimasefedwa kudzera mu sieve ya 60-120 kuti zigwiritsidwe ntchito mtsogolo;
Sankhani nkhungu malinga ndi mawonekedwe omwe mukufuna, ikani zinthu zopyapyala mu dzenje la nkhungu, ndipo chitani kupondereza kutentha kwa chipinda pa mphamvu ya 50-200MPa kuti mupeze thupi lobiriwira; kapena ikani thupi lobiriwira mutapondereza mu chipangizo chopondereza cha isostatic, chitani kupondereza kwa isostatic pa mphamvu ya 200-300MPa, ndipo pezani thupi lobiriwira mutapondereza kachiwiri;
Ikani thupi lobiriwira lomwe lakonzedwa pamwambapa mu ng'anjo yotenthetsera vacuum kuti itenthe, ndipo yoyenera ndi silicon carbide bulletproof ceramic yomalizidwa; mu ndondomeko yotenthetsera yomwe ili pamwambapa, choyamba chotsani ng'anjo yotenthetsera, ndipo digiri ya vacuum ikafika 3-5 × 10-2 Pambuyo pa Pa, mpweya wosagwira ntchito umadutsa mu ng'anjo yotenthetsera ku mphamvu yachibadwa kenako n’kutenthedwa. Ubale pakati pa kutentha ndi nthawi ndi: kutentha kwa chipinda kufika 800℃, maola 5-8, kutentha kusungidwa kwa ola 0.5-1, kuyambira 800℃ mpaka 2000-2300℃, maola 6-9, kutentha kusungidwa kwa ola limodzi mpaka awiri, kenako kuziziritsidwa ndi ng'anjo ndikutsitsidwa kutentha kwa chipinda.
Kapangidwe kakang'ono ndi malire a tirigu wa silicon carbide wothira pa mphamvu yachibadwa
Mwachidule, ma ceramic opangidwa ndi njira yopopera kutentha amakhala ndi magwiridwe antchito abwino, koma mtengo wopangira umawonjezekanso kwambiri; ma ceramic opangidwa ndi njira yopopera yopanda mphamvu amakhala ndi zofunikira kwambiri pazinthu zopangira, kutentha kwambiri kwa sintering, kusintha kwakukulu kwa kukula kwa chinthu, njira yovuta komanso magwiridwe antchito otsika; zinthu za ceramic zopangidwa ndi njira yopopera kutentha zimakhala ndi kuchuluka kwakukulu, magwiridwe antchito abwino otsutsana ndi mpira, komanso mtengo wotsika wokonzekera. Njira zosiyanasiyana zokonzekera sintering za ma silicon carbide ceramics zimakhala ndi zabwino ndi zovuta zake, ndipo zochitika zogwiritsira ntchito zidzakhalanso zosiyana. Ndi mfundo yabwino kusankha njira yoyenera yokonzekera malinga ndi malonda ndikupeza mgwirizano pakati pa mtengo wotsika ndi magwiridwe antchito apamwamba.
Nthawi yotumizira: Okutobala-29-2024