Reaction sintering
The reaction sinteringsilicon carbide ceramicts'ebetso ea tlhahiso e kenyelletsa compacting ea ceramic, sintering flux infiltration agent compacting, reaction sintering ceramic product preparation, silicon carbide patsi ho lokisetsa ceramic le mehato e meng.
Reaction sintering silicon carbide nozzle
Ntlha ea pele, 80-90% ea phofo ea ceramic (e entsoeng ka phofo e le 'ngoe kapa tse peli tsasilicon carbide phofole boron carbide powder), 3-15% ea carbon source phofo (e entsoeng ka e le 'ngoe kapa tse peli tsa carbon black le phenolic resin) le 5-15% ea molding agent (phenolic resin, polyethylene glycol, hydroxymethyl cellulose kapa parafine) li kopantsoe ka ho lekana. ho sebelisa leloala la bolo ho fumana phofo e tsoakiloeng, e fafalitsoeng e omisitsoeng le granulated, ebe e hatelloa ka hlobo ho fumana compact ea ceramic e nang le mefuta e fapaneng e ikhethang. libopeho.
Taba ea bobeli, phofo ea silicon ea 60-80%, 3-10% silicon carbide powder le 37-10% boron nitride powder li tsoakoa ka ho lekana, 'me li hatelloa ka foromo ho fumana compact ea sintering flux infiltration agent.
Ceramic compact le sintered infiltrant compact e ntan'o koalloa hammoho, 'me mocheso o phahamisetsoa ho 1450-1750 ℃ ka seboping sa vacuum se nang le vacuum degree e seng ka tlase ho 5 × 10-1 Pa bakeng sa sintering le ho boloka mocheso bakeng sa 1-3. lihora tse ngata ho fumana sehlahisoa sa sintered ceramic. Masala a kenang ka holim'a sintered ceramic a tlosoa ka ho tlanya ho fumana letlapa le teteaneng la ceramic, 'me sebopeho sa pele sa compact se bolokiloe.
Qetellong, ts'ebetso ea sintering ea karabelo e amoheloa, ke hore, silicon ea metsi kapa silicon alloy e nang le ts'ebetso ea karabelo mochesong o phahameng e kenella ka har'a sekheo sa porous ceramic e nang le khabone tlas'a ketso ea matla a capillary, 'me e kopana le khabone e ho eona ho theha silicon carbide, eo. e tla hola ka bongata, 'me li-pores tse setseng li tlatsitsoe ka silicon ea mantlha. Sekheo sa ceramic se nang le porous e ka ba carbon e hloekileng kapa silicon carbide / carbon-based composite material. Ea pele e fumanoa ka ho phekola ka mokhoa o ts'oanelang le ka pyrolyzing resin ea tlhaho, pore ea pele le solvent. Ea ho qetela e fumanoa ka pyrolyzing silicon carbide particles/resin-based composite materials ho fumana silicon carbide/carbon-based composite thepa, kapa ka ho sebelisa α-SiC le carbon powder e le lisebelisoa tsa ho qala le ho sebelisa mochine oa khatiso kapa oa ente ho fumana motsoako. thepa.
Ho qoela ka ntle ho khatello
Ts'ebetso ea sintering e senang khatello ea silicon carbide e ka aroloa ka sintering e tiileng-mohato le sintering ea mokelikeli. Lilemong tsa morao tjena, lipatlisiso kali-ceramics tsa silicon carbidelapeng le kantle ho naha e tsepamisitse maikutlo haholo ho mokelikeli-phase sintering. Mokhoa oa ho lokisa ka ceramic ke: ho sila lintho tse tsoakiloeng -> spray granulation–> dry pressing–> green body solidification–> vacuum sintering.
Lihlahisoa tse se nang khatello tsa sintered silicon carbide
Kenya likarolo tse 96-99 tsa silicon carbide ultrafine powder (50-500nm), 1-2 likarolo tsa boron carbide ultrafine powder (50-500nm), 0.2-1 likarolo tsa nano-titanium boride (30-80nm), likarolo tse 10-20 ea resin ea phenolic e qhibilihang ka metsing, le likarolo tse 0.1-0.5 tse sebetsang hantle haholo dispersant ho leloala bolo bakeng sa ho sila bolo le ho kopanya bakeng sa lihora tse 24, 'me u kenye slurry e tsoakiloeng ka har'a moqomo oa ho kopanya bakeng sa ho hlohlelletsa lihora tse 2 ho tlosa li-bubble ka har'a slurry.
Motsoako o ka holimo o fafatsoa ka tora ea granulation, 'me phofshoana ea granulation e nang le morphology e ntle ea phatsa, metsi a monate, moqotetsane oa kabo ea likaroloana le mongobo o itekanetseng o fumanoa ka ho laola khatello ea spray, mocheso o kenang moeeng, mocheso oa mocheso oa moea le boholo ba pampiri ea spray. Phetoho ea maqhubu a centrifugal ke 26-32, mocheso oa moea o kenang ke 250-280 ℃, mocheso o tsoang ho moea ke 100-120 ℃, 'me khatello ea slurry inlet ke 40-60.
Phofo e ka holimo ea granulation e kenngoa ka har'a hlobo e entsoeng ka samente ea carbide bakeng sa ho hatella ho fumana 'mele o motala. Mokhoa oa ho hatella ke khatello ea mahlakore a mabeli, 'me khatello ea mochine oa mochine ke lithane tse 150-200.
'Mele o motala o hatelitsoeng o kenngoa ka ontong ea ho omisa bakeng sa ho omisoa le ho phekola ho fumana' mele o motala o nang le matla a matle a 'mele o motala.
'Mele o motala o phekotsoeng ka holimo o behiloe kagraphite cruciblele ho hlophisoa haufi-ufi le ka makhethe, 'me joale graphite crucible e nang le' mele o motala e behoa ka sebōpi se phahameng sa mocheso oa vacuum sintering bakeng sa ho thunngoa. Mocheso oa ho chesa ke 2200-2250 ℃, 'me nako ea ho kenya letsoho ke lihora tse 1-2. Qetellong, li-ceramics tsa silicon carbide tse sa sebetseng hantle li fumaneha.
Mokhahlelo o tiileng oa sintering
Ts'ebetso ea sintering e senang khatello ea silicon carbide e ka aroloa ka sintering e tiileng-mohato le sintering ea mokelikeli. Liquid-phase sintering e hloka tlatsetso ea li-additives tsa sintering, joalo ka Y2O3 binary le ternary additives, ho etsa hore SiC le lisebelisoa tsa eona tse kopaneng li hlahise sintering ea mokelikeli le ho fihlela densification ka mocheso o tlase. Mokhoa oa ho lokisa lirafshoa tse tiileng tsa silicon carbide ceramics li kenyelletsa ho kopanya lisebelisoa tse tala, granulation ea spray, ho bopa le ho sila ka vacuum. Mokhoa o khethehileng oa tlhahiso ke o latelang:
70-90% ea submicron α silicon carbide (200-500nm), 0.1-5% ea boron carbide, 4-20% ea resin, le 5-20% ea organic binder e kenngoa ka motsoako ebe e kenngoa ka metsi a hloekileng bakeng sa metsi. ho kopanya. Ka mor'a lihora tse 6-48, slurry e tsoakiloeng e fetisoa ka sieve ea 60-120 mesh;
The sieved slurry e fafatsa granulated ka tora ea spray granulation. Mocheso o kenang oa tora ea granulation ea spray ke 180-260 ℃, 'me mocheso oa ho tsoa ke 60-120 ℃; boima ba bongata ba thepa ea granulated ke 0.85-0.92g/cm3, fluidity ke 8-11s/30g; thepa e nang le granulated e hloekisoa ka 60-120 mesh sieve bakeng sa tšebeliso ea hamorao;
Khetha hlobo ho latela sebopeho sa sehlahisoa se lakatsehang, kenya thepa e nang le granulated ka har'a sekoaelo sa hlobo, 'me u etse mohatla oa mocheso oa kamore ka khatello ea 50-200MPa ho fumana 'mele o motala; kapa beha 'mele o motala ka mor'a ho bōptjoa ha khatello ho sesebelisoa sa ho hatella sa isostatic, etsa khatello ea isostatic ka khatello ea 200-300MPa,' me u fumane 'mele o motala ka mor'a ho hatella bobeli;
Kenya 'mele o motala o lokisitsoeng ka mehato e ka holimo ka har'a sebōpi sa vacuum sintering bakeng sa sintering,' me ea tšoanelehang ke ceramic e phethiloeng ea silicon carbide bulletproof ceramic; ts'ebetsong e ka holimo ea sintering, qala ka ho tlosa sebōpi sa sintering, 'me ha tekanyo ea vacuum e fihla ho 3-5 × 10-2 Ka mor'a Pa, khase ea inert e fetisetsoa ka sebōping sa sintering ho khatello e tloaelehileng ebe e futhumatsoa. Kamano pakeng tsa mocheso oa mocheso le nako ke: mocheso oa kamore ho 800 ℃, lihora tse 5-8, ho boloka mocheso bakeng sa hora ea 0.5-1, ho tloha 800 ℃ ho ea 2000-2300 ℃, lihora tse 6-9, ho boloka mocheso bakeng sa lihora tse 1 ho isa ho tse peli, ebe o pholile ka sebōpi ebe o theohela mocheso oa kamore.
Microstructure le moeli oa lijo-thollo oa silicon carbide sintered ka khatello e tloaelehileng
Ka bokhutšoanyane, li-ceramics tse entsoeng ka mokhoa o chesang oa sintering li na le ts'ebetso e ntle, empa litšenyehelo tsa tlhahiso le tsona li eketsehile haholo; li-ceramics tse lokiselitsoeng ke sintering e se nang khatello li na le litlhoko tse phahameng tsa thepa e tala, mocheso o phahameng oa sintering, liphetoho tse kholo tsa sehlahisoa, ts'ebetso e rarahaneng le ts'ebetso e tlase; Lihlahisoa tsa ceramic tse hlahisoang ke ts'ebetso ea sintering ea karabelo li na le letsoalo le phahameng, ts'ebetso e ntle ea anti-ballistic, le litšenyehelo tse tlase tsa ho itokisa. Mekhoa e fapaneng ea ho lokisa sintering ea silicon carbide ceramics e na le melemo le melemo ea eona, 'me maemo a ts'ebeliso le ona a tla fapana. Ke leano le molemo ka ho fetisisa la ho khetha mokhoa o nepahetseng oa ho lokisetsa ho ea ka sehlahisoa le ho fumana tekanyo pakeng tsa theko e tlaase le ts'ebetso e phahameng.
Nako ea poso: Oct-29-2024