1. Sebopeho sa Crystal le Polytypism ea Silicon Carbide
1.1 Li-Cubic le Hexagonal Polytypes: Ho tloha ho 3C ho isa ho 6H le Nakong e Fetileng
(Silicon Carbide Ceramics)
Silicon carbide (SiC) ke ceramic e khomaretsoeng ka thata e entsoeng ka silicon le liathomo tsa khabone tse hlophisitsoeng ka har'a tetrahedral sychronisation., ho theha e 'ngoe ea litsamaiso tse rarahaneng ka ho fetisisa tsa polytypism ho mahlale a thepa.
Ho fapana le li-ceramics tse ngata tse nang le moralo o le mong o tsitsitseng oa kristale, SiC e teng ka morao 250 li-polytype tse tsebahalang– tatellano e ikhethang ea li-bilayers tsa Si-C tse haufi-ufi haufi le c-axis– e fapaneng ho tloha ho li-cubic 3C-SiC (e boetse e bitsoa β-SiC) ho ea ho hexagonal 6H-SiC le rhombohedral 15R-SiC.
E 'ngoe ea li-polytype tse tloaelehileng tse sebelisoang lits'ebetsong tsa moralo ke 3C (cubic), 4H, le 6h (ka bobeli ba mahlakore a mararo), e 'ngoe le e' ngoe e bonts'a mefuta e sa tšoaneng ea lihlopha tsa elektronike le li-conductivity tsa mocheso.
3C-SiC, ka moralo oa eona oa motsoako oa zinki, e na le lekhalo le moqotetsane (~ 2.3 eV) 'me hangata e atolosoa holim'a li-silicon substrates bakeng sa lisebelisoa tsa semiconductor, ha 4H-SiC e fana ka phetoho e tsotehang ea elektronike 'me e ratoa bakeng sa lisebelisoa tsa elektroniki tse matla haholo.
Sebopeho se tiileng sa covalent le sebopeho sa tataiso sa Si– C bond e fana ka botsitso bo ikhethang, tshireletso ya mocheso, le ho hanyetsa ho thella le tlhaselo ea lik'hemik'hale, ho etsa hore SiC e be e loketseng bakeng sa lits'ebetso tse feteletseng tsa tikoloho.
1.2 Litaba, Doping, le Digital Residence
Ho sa tsotelehe ho rarahana ha eona hoa sebopeho, SiC e ka etsoa doped ho fumana bobeli ba n-type le p-type conductivity, e lumellang tšebeliso ea eona ho lisebelisoa tsa semiconductor.
Nitrojene le phosphorus li sebetsa e le lintho tse silafatsang, ho hlahisa li-electrone hantle ka har'a sehlopha sa phetiso, ha aluminium e boima bo bobebe le boron e sebetsa e le ba amohelang, ho hlahisa masoba sehlopheng sa valence.
Leha ho le joalo, Ts'ebetso ea doping ea mofuta oa p e thibetsoe ke matla a phahameng a ho kenya tšebetsong, haholo-holo ho 4H-SiC, e behang litšitiso bakeng sa moralo oa sesebelisoa sa bipolar.
Litšitiso tsa tlhaho joalo ka li-screw tse fosahetseng, li-micropipe, 'me liphoso tsa ho bokella li ka fokolisa ts'ebetso ea lisebelisoa ka ho sebetsa e le lisebelisoa tsa ho kopanya kapa lithuto tsa ho lutla, e batlang ntshetsopele ea top notch single-crystal bakeng sa lits'ebetso tsa elektroniki.
Lekhalo le leholo (2.3– 3.3 eV ho itšetlehile ka polytype), sebaka se phahameng sa motlakase (~ 3 MV/cm), le conductivity e babatsehang ea mocheso (~ 3– 4 W/m · K bakeng sa 4H-SiC) etsa hore SiC e phahame haholo ho feta silicon ka mocheso o phahameng, matla a phahameng, le lisebelisoa tsa elektronike tsa maqhubu a phahameng.
2. Ho sebetsana le Moralo oa Microstructural
( Silicon Carbide Ceramics)
2.1 Sintering le Densification Techniques
Silicon carbide ka tlhaho ho thata ho e tiisa ka lebaka la tlamahano e matla ea covalent le ho fokotsa li-coefficients tsa ho itšehla thajana., ho hloka mekhoa e mecha ea ho sebetsa ho fihlela boima bo felletseng ntle le li-additives kapa ka thuso e nyane haholo ea sintering.
Ho nolofalloa ho se nang khatello ea li-powder tsa submicron SiC hoa khoneha ka ntlafatso ea boron le carbon, e khothalletsang densification ka ho felisa likarolo tsa oxide le ho matlafatsa ho hasana ha boemo bo tiileng.
Ho sututsa ka mofuthu ho sebetsa khatello ea uniaxial nakong ea ho futhumatsa ntlo, ho lumella densification e feletseng maemong a fokotsehileng a mocheso (~ lilemo tse 1800– 2000 °C )le ho hlahisa litholoana tse ntle, lisebelisoa tse matla tse phahameng tse loketseng ho fokotsa lisebelisoa le ho kenya likarolo.
Bakeng sa libopeho tse kholo kapa tse rarahaneng, tlamahano ea karabo e sebelisoa, moo li-preforms tsa porous carbon li kenngoeng ka silicon e qhibilihisitsoeng ho ~ 1600 °C, ho theha β-SiC in situ e nang le shrinkage e nyane.
Leha ho le joalo, silicon e se nang theko e setseng (~ 5– 10%) e sala ka har'a microstructure, ho fokotsa katleho ea mocheso o phahameng le khanyetso ea oxidation ka holimo 1300 °C.
2.2 Tlhahiso e Ekelitsoeng le Tlhahiso ea Near-Net-Shape Manufacture
Khatelo-pele ea hona joale tlhahisong ea li-additive (AM), ka ho khetheha binder jetting le stereolithography ho sebelisa SiC powders kapa preceramic polymers, lumella ho etsoa ha li-geometri tse rarahaneng tseo pele li neng li sa fihlellehe ka mekhoa e tloaelehileng.
Ka ceramic e entsoeng ka polymer (PDC) litsela, Li-preerunners tsa SiC tsa mokelikeli li thehoa ka khatiso ea 3D ebe li kenngoa ka pyrolyzed ka mocheso ho hlahisa amorphous kapa nanocrystalline SiC., hangata e hlokang tšubuhlellano e eketsehileng.
Mekhoa ena e theola litheko tsa machining le litšila tsa lihlahisoa, ho etsa hore SiC e fumanehe haholoanyane bakeng sa sefofane, nuclear, le lisebelisoa tse futhumetseng tsa phapanyetsano moo litlhophiso tse rarahaneng li ntlafatsang katleho.
Liketso tsa morao-rao tse kang ho kenella ha mouoane oa lik'hemik'hale (CVI) kapa silicon e nang le metsi a phallang (LSI) ka linako tse ling li sebelisoa ho ntlafatsa density le botsitso ba mochini.
3. Mechini, Mocheso, le Sebetsa sa Tikoloho
3.1 Matla, Ho thatafala, le Sebelisa Resistance
Silicon carbide e har'a lihlahisoa tse thata ka ho fetisisa tse tsebahalang, ka botsitso ba Mohs ba ~ 9.5 le Vickers ho tiea ho fetisisang 25 Karolelano ea lintlha tsa mophato, ho etsa hore e se ke ya tshoaroa haholo, pherekano, le ho hohla.
Matla a eona a flexural ka kakaretso a tloha ho 300 ho 600 MPa, ho itšetleha ka mokhoa oa ho sebetsa le boholo ba lijo-thollo, 'me e boloka ho thatafala ha mocheso ho fihlela 1400 ° C maemong a sa tsitsang.
Matla a ho robeha, ha a ntse a inyenyefatsa (~ 3– 4 MPa · m 1ST/ TWO), e lekane bakeng sa lits'ebetso tse ngata tsa meralo, ka ho khetheha ha e kopantsoe le tšehetso ea fiber ka har'a metsoako ea matrix ea ceramic (Li-CMCs).
Li-CMC tse thehiloeng ho SiC li sebelisoa ka mahare a turbine, li-combustor linings, le litsamaiso tsa mariki, moo ba fanang ka ho boloka litšenyehelo tsa boima, khase e sebetsang hantle, le bophelo bo bolelele ba ts'ebeletso holim'a lisebelisoa tsa tšepe.
Ho hanyetsa ha eona ho ikhethang ho etsa hore SiC e be e loketseng litiiso, dibering, likarolo tsa pompo, le thebe ea ballistic, moo ho leng bohlokoa haholo tlas'a phallo e feteletseng ea mochini.
3.2 Thermal Conductivity le Oxidation Security
E 'ngoe ea thepa ea bohlokoa ea bolulo kapa ea khoebo ea SiC ke ts'ebetso ea eona e phahameng ea mocheso– hoo e ka bang 490 W/m · K bakeng sa single-crystal 4H-SiC le ~ 30– 120 W/m · K bakeng sa mefuta ea polycrystalline– ho fetela ka nģ'ane ho litšepe tse ngata le ho etsa hore ho khonehe bakeng sa ho qhala mocheso ka katleho.
Thepa ena ea bolulo e bohlokoa ho lisebelisoa tsa motlakase tsa motlakase, moo lisebelisoa tsa SiC li hlahisang mocheso o fokolang oa litšila 'me li ka sebetsa ka matla a maholo ho feta lisebelisoa tse thehiloeng ka silicon.
Maemong a phahameng a mocheso libakeng tse nang le oxidizing, SiC e etsa silika e sireletsang (SiO ₂) lera le fokotsang oxidation e eketsehileng, e fanang ka botsitso bo botle ba tikoloho joalo ka ~ 1600 °C.
Leha ho le joalo, libakeng tse nang le mouoane oa metsi, lera ena ka volatilize e le Si(OH)₄, se bakang tshenyeho e potlakileng– phephetso ea mantlha lits'ebetsong tsa mochini oa khase.
4. Lisebelisoa tse tsoetseng pele ho Matla, Lisebelisoa tsa Elektronike, le Aerospace
4.1 Lisebelisoa tsa Matla a Elektronike le Lisebelisoa tsa Semiconductor
Silicon carbide e fetotse lisebelisoa tsa motlakase ka ho etsa hore ho khonehe bakeng sa lisebelisoa tse kang Schottky diode., MOSFETs, le li-JFET tse sebetsang ka matla a holimo, maqhubu, le thempereichara ho feta ho bapisoa ha silicon.
Lisebelisoa tsena li fokotsa tahlehelo ea matla likoloing tsa motlakase, li-inverters tsa matla tse nchafalitsoeng, le likoloi tsa motlakase tsa khoebo, ho eketsa matla a lefats'e a sebetsang hantle.
Bokhoni ba ho matha maemong a mocheso a mateano ho feta 200 ° C e lumella litsamaiso tse pholileng tse ntlafalitsoeng le ts'epahalo e phahamisitsoeng ea sistimi.
Ho feta moo, Li-wafers tsa SiC li sebelisoa e le li-substratum tsa gallium nitride (GaN) epitaxy ka li-transistors tse phahameng tsa elektronike (HEMTs), ho kopanya melemo ea bobeli ba li-semiconductors tse pharaletseng.
4.2 Nyutlelie, Sepakapaka, le Lisebelisoa tsa Optical
Limeleng tsa matla a athomo, SiC ke karolo ea bohlokoa ea ho koaheloa ha mafura a mamelle likotsi, moo ho monyeng ha nyutrone ho fokotsehile, ho hanyetsa mahlaseli, le ho tiea ha mocheso o phahameng ho ntlafatsa polokeho le ts'ireletso le bokhoni.
Sebakeng sa sefofane, Li-composite tsa SiC fiber-reinforced li sebelisoa lienjineng tsa jet le likoloing tsa hypersonic bakeng sa botsitso ba tsona bo bobebe le mocheso..
Ho feta moo, Liipone tsa SiC tse boreleli li sebelisoa pele ho libonela-hōle ka lebaka la ho satalla ho hoholo ha tsona., botsitso ba mocheso, le ho benyang ho ba mahoashe a sub-nanometer.
Ka kakaretso, li-ceramics tsa silicon carbide li emela lejoe la sehlooho la lisebelisoa tsa morao-rao tse tsoetseng pele, ho kopanya mochine o ikhethang, mocheso, le thepa ea digital.
Ka taolo e khethehileng ea polytype, microstructure, le ho tshwara, SiC e sala e le ho nolofalletsa mekhoa ea theknoloji ka matla, sepalangoang, le boenjiniere ba maemo a feteletseng.
5. Mofani
TRUNNANO ke morekisi oa Spherical Tungsten Powder e nang le over 12 lilemo tsa boiphihlelo ba ho boloka matla a nano-building le nts'etsopele ea nanotechnology. E amohela tefo ka Credit Card, T/T, West Union le Paypal. Trunnano e tla romella thepa ho bareki ba mose ho maoatle ka FedEx, DHL, ka moea, kapa ka lewatle. Haeba u batla ho tseba haholoanyane ka Spherical Tungsten Powder, ka kopo ikutloe u lokolohile ho ikopanya le rona le ho romela potso([email protected]).
Li-tag: silicon carbide ceramic,lihlahisoa tsa silicon carbide ceramic, indasteri ea ceramic
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