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 ufa), 3-15% ya mpweya gwero ufa (wopangidwa ndi mmodzi kapena awiri a mpweya wakuda ndi phenolic utomoni) ndi 5-15% ya akamaumba wothandizila (phenolic utomoni, polyethylene glycol, hydroxymethyl mapadi kapena parafini) amasakanizidwa wogawana ntchito mphero mphero kupeza ufa wosanganiza, amene ndi utsi wothira ndi zouma nkhungu ndi atolankhani zosiyanasiyana 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 yaying'ono ndi sintered infiltrant yaying'ono imayikidwa palimodzi, ndipo kutentha kumakwera mpaka 1450-1750 ℃ mu ng'anjo ya vacuum ndi digiri ya vacuum yosachepera 5 × 10-1 Pa posungira ndi kusunga kutentha kwa maola 1-3 kuti mupeze chochita cha sintered ceramic. Zotsalira zolowera pamwamba pa sintered ceramic zimachotsedwa pogogoda kuti mupeze pepala lolimba la ceramic, ndipo mawonekedwe oyambirira a compact amasungidwa.
Pomaliza, zimene sintering ndondomeko anatengera, ndiko kuti, madzi pakachitsulo kapena pakachitsulo aloyi ndi zochita pa kutentha akulowerera infiltrates mu porous ceramic opanda kanthu munali mpweya pansi zochita za capillary mphamvu, ndi amachitira ndi mpweya mmenemo kupanga silicon carbide, amene adzakulitsa voliyumu, ndi pores otsala amadzazidwa ndi zoyambira 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 ufa wa carbon monga zipangizo zoyambira ndikugwiritsa ntchito njira yopondereza kapena jekeseni kuti mupeze zinthu zambiri.
Kuyimba mopanda kukakamiza
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
Onjezerani 96-99 mbali za silicon carbide ultrafine powder (50-500nm), 1-2 mbali za boron carbide ultrafine powder (50-500nm), 0.2-1 mbali za nano-titaniyamu boride (30-80nm), 10-20 magawo a madzi osungunuka, 0-phenolic osungunuka kwambiri, 0-0-phenolic. 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 kwamoto 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 ndi kuwonjezeredwa ndi madzi oyera kusakaniza konyowa. 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, kusunga kutentha kwa ola la 0.5-1, kuchokera ku 800 ℃ mpaka 2000-2300 ℃, maola 6-9, kusunga kutentha kwa maola 1 mpaka 2, kenako kuzirala ndi ng'anjo ndikugwera kutentha.
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 kwambiri yosankha njira yoyenera yokonzekera molingana ndi mankhwala ndikupeza malire pakati pa mtengo wotsika ndi ntchito yapamwamba.
Nthawi yotumiza: Oct-29-2024