Reaction sintering
The anachita sinteringsilicon carbide ceramickupanga zikuphatikizapo ceramic compacting, sintering flux kulowa wothandizila compacting, anachita sintering ceramic mankhwala kukonzekera, pakachitsulo carbide nkhuni kukonzekera ceramic ndi masitepe ena.
Rection sintering silicon carbide nozzle
Choyamba, 80-90% ya ufa wa ceramic (wopangidwa ndi ufa umodzi kapena awiri wasilicon carbide ufandi boron carbide powder), 3-15% ya carbon source powder (yopangidwa ndi imodzi kapena ziwiri za carbon black ndi phenolic resin) ndi 5-15% ya woumba (phenolic resin, polyethylene glycol, hydroxymethyl cellulose kapena parafini) amasakanizidwa mofanana. ntchito mpira mphero kupeza ufa wosanganiza, amene utsi zouma ndi granulated, ndiyeno mbamuikha mu nkhungu kupeza ceramic yaying'ono zosiyanasiyana enieni. mawonekedwe.
Kachiwiri, 60-80% silicon ufa, 3-10% silicon carbide ufa ndi 37-10% boron nitride ufa amasakanizidwa mofanana, ndi kukanikizidwa mu nkhungu kuti apeze sintering flux infiltration agent yaying'ono.
Ceramic compact ndi sintered infiltrant compact kenako zimayikidwa palimodzi, ndipo kutentha kumakwezedwa mpaka 1450-1750 ℃ mu ng'anjo yopanda kanthu yokhala ndi digiri ya vacuum yosachepera 5 × 10-1 Pa posungira ndi kuteteza kutentha kwa 1-3. maola kupeza anachita sintered ceramic mankhwala. Zotsalira zolowera pamwamba pa sintered ceramic zimachotsedwa pogogoda kuti mupeze pepala lolimba la ceramic, ndipo mawonekedwe oyambirira a compact amasungidwa.
Pomaliza, zochita sintering ndondomeko anatengera, ndiko kuti, madzi pakachitsulo kapena pakachitsulo aloyi ndi zochita pa kutentha amalowa mu porous ceramic opanda kanthu munali mpweya pansi pa zochita za capillary mphamvu, ndi amachitira ndi mpweya mmenemo kupanga silicon carbide, amene. zidzakula mu voliyumu, ndipo pores otsala amadzazidwa ndi elemental silicon. Chopanda kanthu cha ceramic chopanda kanthu chikhoza kukhala cha carbon kapena silicon carbide / carbon-based composite material. Yoyamba imapezeka pochiritsa ndi pyrolyzing organic resin, pore kale ndi zosungunulira. Zotsirizirazi zimapezedwa ndi pyrolyzing silicon carbide particles / resin-based composite materials kupeza silicon carbide / carbon-based composite materials, kapena pogwiritsa ntchito α-SiC ndi carbon powder monga zipangizo zoyambira ndikugwiritsa ntchito makina osindikizira kapena jekeseni kuti apeze gulu. zakuthupi.
Kuyimba mosavutikira
Njira yopangira sintering yopanda pake ya silicon carbide imatha kugawidwa kukhala yolimba-gawo sintering ndi madzi-gawo sintering. M'zaka zaposachedwapa, kafukufuku pasilicon carbide ceramicskunyumba ndi kunja makamaka lolunjika pa madzi-gawo sintering. Kukonzekera kwa ceramic ndi: mphero zosakanikirana za mpira-> kupopera granulation-> kukanikiza kowuma-> kulimba kwa thupi lobiriwira->kupukuta kwa vacuum.
Pressureless sintered silicon carbide mankhwala
Onjezani magawo 96-99 a silicon carbide ultrafine powder (50-500nm), 1-2 mbali za boron carbide ultrafine powder (50-500nm), 0.2-1 mbali za nano-titanium boride (30-80nm), 10-20 mbali wa madzi osungunuka a phenolic resin, ndi 0.1-0.5 magawo apamwamba kwambiri dispersant kwa mpira mphero kwa mpira mphero ndi kusakaniza kwa maola 24, ndi kuika osakaniza slurry mu kusakaniza mbiya kwa oyambitsa kwa 2 hours kuchotsa thovu mu slurry.
The pamwamba osakaniza ndi sprayed mu granulation nsanja, ndi granulation ufa ndi zabwino tinthu morphology, zabwino fluidity, yopapatiza tinthu kugawa osiyanasiyana ndi zolimbitsa chinyezi akamagwira kulamulira kutsitsi kuthamanga, mpweya polowera kutentha, mpweya kubwereketsa kutentha ndi kutsitsi pepala tinthu kukula. Kutembenuka kwafupipafupi kwa centrifugal ndi 26-32, kutentha kwa mpweya ndi 250-280 ℃, kutentha kwa mpweya ndi 100-120 ℃, ndi slurry inlet pressure ndi 40-60.
Pamwambapa granulation ufa amaikidwa mu simenti nkhungu carbide kukanikiza kupeza thupi wobiriwira. The kukanikiza njira ndi bidirectional kuthamanga, ndi makina chida kuthamanga tonnage ndi 150-200 matani.
Thupi lobiriwira lopanikizidwa limayikidwa mu ng'anjo yowumitsa kuti awunike ndi kuchiritsa kuti apeze thupi lobiriwira lomwe lili ndi mphamvu zobiriwira bwino.
Thupi lobiriwira lomwe lachiritsidwa pamwambapa limayikidwa mu agraphite cruciblendi anakonza mwaukhondo ndi mwaukhondo, ndiyeno graphite crucible ndi thupi wobiriwira anaika mu mkulu-kutentha zingalowe sintering ng'anjo kuwombera. Kutentha kwa moto ndi 2200-2250 ℃, ndipo nthawi yotchinjiriza ndi maola 1-2. Potsirizira pake, zoumba zapamwamba za sintered sintered silicon carbide zimapezedwa.
Solid-phase sintering
Njira yopangira sintering yopanda pake ya silicon carbide imatha kugawidwa kukhala yolimba-gawo sintering ndi madzi-gawo sintering. Liquid-phase sintering imafuna kuwonjezera kwa sintering additives, monga Y2O3 binary ndi ternary additives, kuti apangitse SiC ndi zida zake zophatikizika kuti zizikhala ndi gawo lamadzimadzi ndikukwaniritsa kutentha pang'ono. Njira yokonzekera zomangira zolimba za sintered silicon carbide ceramics zimaphatikizapo kusakaniza zopangira, kupopera granulation, kuumba, ndi vacuum sintering. Kupanga kwapadera kuli motere:
70-90% ya submicron α silicon carbide (200-500nm), 0.1-5% ya boron carbide, 4-20% ya utomoni, ndi 5-20% ya organic binder amayikidwa mu chosakanizira ndikuwonjezedwa ndi madzi oyera kuti anyowe. kusakaniza. Pambuyo pa maola 6-48, slurry yosakanikirana imadutsa mu sieve ya 60-120 mesh;
Sieved slurry ndi kupopera granulated kupyolera mu spray granulation tower. Kutentha kolowera kwa nsanja yopoperapo granulation ndi 180-260 ℃, ndipo kutentha kotuluka ndi 60-120 ℃; kachulukidwe wochuluka wa zinthu granulated ndi 0.85-0.92g/cm3, fluidity ndi 8-11s/30g; zinthu za granulated zimasefa kudzera mu sieve ya 60-120 mesh kuti igwiritsidwe ntchito mtsogolo;
Sankhani nkhungu molingana ndi mawonekedwe omwe mukufuna, tsitsani zinthu za granulated mu nkhungu, ndikuchita kutentha kwa chipinda pamitsempha ya 50-200MPa kuti mupeze thupi lobiriwira; kapena ikani thupi lobiriwira mukamawumba mu chipangizo chosindikizira cha isostatic, pangani kuponderezana kwa isostatic pamphamvu ya 200-300MPa, ndikupeza thupi lobiriwira pambuyo pa kukanikiza kwachiwiri;
Ikani thupi lobiriwira lomwe lakonzedwa m'masitepe omwe ali pamwambawa mu ng'anjo ya vacuum sintering kuti muwotche, ndipo woyenerera ndi ceramic yomalizidwa ya silicon carbide bulletproof ceramic; mu ndondomeko pamwamba sintering, choyamba chotsani ng'anjo sintering, ndipo pamene vacuum digiri kufika 3-5 × 10-2 Pambuyo Pa, mpweya inert amadutsa mu ng'anjo sintering kupanikizika yachibadwa ndiyeno kutentha. Ubale pakati pa kutentha kwa kutentha ndi nthawi ndi: kutentha kwa chipinda mpaka 800 ℃, maola 5-8, kuteteza kutentha kwa ola la 0.5-1, kuchokera ku 800 ℃ mpaka 2000-2300 ℃, maola 6-9, kusunga kutentha kwa maola 1 mpaka 2, ndiyeno utakhazikika ndi ng'anjo ndikugwetsa kutentha firiji.
Microstructure ndi malire a tirigu a silicon carbide sintered at normal pressure
Mwachidule, zitsulo zopangidwa ndi kutentha kwa sintering zimagwira ntchito bwino, koma mtengo wopangira umakulanso kwambiri; zitsulo zokonzedwa ndi sintering zopanda pake zimakhala ndi zofunikira zapamwamba zakuthupi, kutentha kwakukulu kwa sintering, kusintha kwakukulu kwazinthu, njira zovuta komanso ntchito yochepa; zinthu za ceramic zopangidwa ndi reaction sintering process zimakhala ndi kachulukidwe kwambiri, magwiridwe antchito abwino odana ndi ballistic, komanso mtengo wotsika wokonzekera. Njira zosiyanasiyana zokonzekera zoumba za silicon carbide ceramics zili ndi zabwino ndi zovuta zake, ndipo mawonekedwe ogwiritsira ntchito adzakhalanso osiyana. Ndilo ndondomeko yabwino yosankha njira yoyenera yokonzekera molingana ndi mankhwala ndikupeza malire pakati pa mtengo wotsika ndi ntchito zapamwamba.
Nthawi yotumiza: Oct-29-2024