1. Kemisi Fakava'e mo e tisaini 'o e Crystallographic 'o e Tekisi ONO .
1.1 Boron-Koloa'ia 'a e Fa'unga mo e Fa'unga 'o e Band Faka'ilekitulonika
(Kalasiume Hekisapolaiti)
Hekisapolaiti kalasiume (TEKISI ₆) ko ha boride ukamea stoichiometric 'oku ha'u mei he hala 'o e hexaborides 'o e kelekele 'oku 'ikai ke fa'a ma'u mo e alkaline-kelekele ., 'oku fakafaikehekehe'i 'aki 'ene fefiofi 'e taha-'o-ha-fa'ahinga 'o e ionic ., kovaleniti, mo e ngaahi 'ulungaanga fakafehokotaki ukamea ..
'Oku 'ave 'e hono fa'unga sio'ata 'a e cubic CsCl-fa'ahinga lattice . (kulupu 'o e 'atakai Pm-3m), 'a ia 'oku nofo ai 'a e ngaahi 'atomi kalasiume 'i he ngaahi tafa'aki 'o e kiupite mo ha fa'unga faingata'a 'o e tolu-dimensional 'o e boron octahedra . (B 6 ngaahi meʻangāue) nofo 'i he fale 'o e sino.
Ko e octahedron takitaha 'o e boron 'oku fa'u 'aki 'a e ngaahi 'atomi boron 'e ono 'oku pipiki covalently 'i ha fokotu'utu'u 'o e symmetric ma'olunga ., fakatupu ha fefeka ., netiueka 'o e 'ilekitulonika-to'o 'oku poupou'i 'e he fe'ave'aki 'o e fakamole mei he 'atomi kalasiume electropositive ..
Ko e fe'ave'aki fakamole ko 'eni 'oku ne taki atu ki ha konga 'o e fe'ave'aki 'o e uta ., endowing tekisī ono mo e conductivity 'uhila ma'olunga ta'e angamaheni ki ha koloa 'o e selami .– ‘i he tu‘utu‘uni ‘o e . 10 S/m 'i he tu'unga mafana 'o e loki– neongo 'ene bandgap lahi 'o e fakafuofua ki he 1.0.– 1.3 eV hange ko ia kuo fokotu'u 'e he ngaahi ako fakatotolo 'o e absorption 'o e optical mo e photoemission ..
Ko e kamata'anga 'o e misiteli ko 'eni .– conductivity ma'olunga 'oku 'i ai 'a e tafa'aki-ki-he-taha mo ha bandgap lahi .– kuo hoko ia ko e kaveinga ‘o ha ako lahi ., mo e ngaahi fakakaukau 'oku fokotu'u mai 'a e 'asi 'o e ngaahi tu'unga 'o e intrinsic flaw ., fetuku funga, pe ngaahi founga fakahoko polaronic kau ai 'a e fakataha'i 'o e 'ilekitulonika-phonon fakalotofonua ..
Recent first-principles calculations sustain a design in which the transmission band minimum obtains largely from Ca 5d orbitals, while the valence band is dominated by B 2p states, producing a slim, dispersive band that promotes electron movement.
1.2 Thermal and Mechanical Security in Extreme Issues
As a refractory ceramic, TAXICAB ₆ shows extraordinary thermal stability, with a melting point exceeding 2200 ° C and negligible weight-loss in inert or vacuum cleaner settings up to 1800 ° C.
Its high disintegration temperature and reduced vapor pressure make it appropriate for high-temperature architectural and practical applications where material honesty under thermal anxiety is important.
Fakamīsini, CaB ₆ possesses a Vickers firmness of roughly 25– 30 GPa, positioning ia 'i he lotolotonga 'o e borides fefeka taha 'oku 'iloa pea 'oku ne fakahaa'i 'a e stamina 'o e B .– B ngaahi ha'i covalent 'i loto 'i he fa'unga 'o e octahedral ..
'Oku fakahaa'i foki 'e he naunau ha coefficient ma'ulalo 'o e fakalahi 'o e mafana . (~ 6.5 × 10 −6/ K), tokoni ki he fakafepaki'i 'o e thermal shock ma'ongo'onga– ko ha tu'unga mahu'inga ki he ngaahi konga 'oku makatu'unga 'i he vave 'o e vela mo e ngaahi siakale 'o e cooling ..
Ko e ngaahi koloa nofo'anga ko 'eni ., fakataha'i mo e kemikale inertness ki he ngaahi ukamea molten mo e slags ., poupouʻi hono fakaʻaongaʻi ʻi he ngaahi kulusi ., ngaahi 'ai'angakai 'o e thermocouple, mo e ngaahi 'iuniti 'o e ongo'i 'o e mafana ma'olunga 'i he metallurgical mo e ngaahi 'atakai 'o e ngaue'anga ..
( Kalasiume Hekisapolaiti)
Pea mo e, 'Oku fakahaa'i 'e he TAXICAB 6 'a e fakafepaki makehe ki he oxidation 'oku lisi atu 'i lalo 1000 ° C; kaikehe, 'i 'olunga 'i he fakangatangata ko 'eni, 'e lava ke hoko 'a e oxidation 'o e funga 'o e kalasiume borate mo e boric oxide ., fie ma'u 'a e ngaahi faka'osi malu'i pe ngaahi pule'i 'o e ngaue 'i he oxidizing ambiences ..
2. Ngaahi Hala Fakatahataha'i mo e tisaini 'o e Microstructural
2.1 Ngaahi Founga Ngaohi Angamaheni mo e Fakalakalaka .
Ko e synthesis 'o e tekisī ma'olunga-ma'a 'o e ono 'oku angamaheni 'aki 'a e ngaahi tali 'o e tu'unga fefeka 'i he vaha'a 'o e kalasiume mo e boron precursors 'i he mafana ma'olunga ..
'Oku kau 'i he ngaahi founga angamaheni 'a e fakasi'isi'i 'o e kalasiume 'okisaiti . (CaO) mo e poloni kāpaiti (B 4 C) pe boron mahu'inga 'i he malumalu 'o e ngaahi tu'unga 'o e inert pe vekiume 'i he ngaahi tu'unga 'o e mafana 'i he vaha'a 'o e . 1200 ° C mo e . 1600 ° C. ^
. 'Oku totonu ke fakatonutonu fakalelei 'a e tali ke faka'ehi'ehi mei he fa'u 'o e ngaahi konga kehe hange ko e taxicab fa pe taxicab TWO ., 'a ia 'e lava ke ne fakakovi'i 'a e fakahoko 'o e 'uhila mo e fakamisini ..
Ko e ngaahi founga kehe 'oku kau ai 'a e carbothermal 'a e fakasi'isi'i ., arc-vaia, mo e mechanochemical synthesis 'o faka'aonga'i 'a e ma'olunga-malohi 'o e polo 'o e milling ., 'a ia 'e lava ke fakasi'isi'i 'a e ngaahi tu'unga 'o e mafana 'o e tali mo e boost homogeneity efuefu ..
Mo e ngaahi konga selami matolu ., ngaahi founga sintering hange ko e lomi'i vela . (HP) or trigger plasma sintering (SPS) are used to accomplish near-theoretical density while decreasing grain growth and maintaining great microstructures.
SPS, specifically, makes it possible for quick consolidation at lower temperatures and shorter dwell times, decreasing the danger of calcium volatilization and preserving stoichiometry.
2.2 Doping and Issue Chemistry for Home Adjusting
One of one of the most considerable breakthroughs in CaB ₆ research study has been the ability to tailor its digital and thermoelectric residential or commercial properties with intentional doping and flaw engineering.
Replacement of calcium with lanthanum (La), cerium (Ce), or other rare-earth elements introduces added fee providers, significantly enhancing electrical conductivity and making it possible for n-type thermoelectric actions.
Similarly, 'e lava ke customize 'e he konga 'o e fetongi 'o e boron 'aki 'a e kaponi pe naitoloseni 'a e matolu 'o e ngaahi tu'unga ofi ki he tu'unga 'o e Fermi ., fakalahi 'a e Seebeck 'a e coefficient mo e fakakatoa 'o e fika 'o e thermoelectric 'o e mahu'inga . (ZT).
Ngaahi me'a fakanatula, tautautefito ki he ngaahi ngaue kalasiume ., fakahoko foki ha ngaue mahu'inga 'i hono fakapapau'i 'o e conductivity ..
'Oku fakahaa'i 'e he ngaahi ako fakatotolo 'oku angamaheni 'aki hono fakahaa'i 'e he tekisī ono 'a e nounou 'o e kalasiume koe'uhi ko e volatilization 'i he kotoa 'o e to'oto'o 'o e mafana ma'olunga ., 'oku taki atu ki he conduction 'o e ava mo e ngaahi ngaue p-fa'ahinga 'i he ngaahi sipinga 'e ni'ihi ..
Regulating stoichiometry via accurate ambience control and encapsulation during synthesis is for that reason vital for reproducible efficiency in digital and power conversion applications.
3. Ngaahi koloa 'aonga mo e Phantasm fakasino 'i he Tekisi ₆ .
3.1 Ngaahi polokalama makehe 'o e tukuange 'o e 'ilekitulonika mo e tukuange 'o e mala'e
CaB ₆ is renowned for its low job function– roughly 2.5 eV– amongst the most affordable for steady ceramic products– making it an exceptional candidate for thermionic and area electron emitters.
This residential or commercial property occurs from the mix of high electron concentration and beneficial surface dipole arrangement, enabling efficient electron emission at reasonably reduced temperature levels contrasted to conventional products like tungsten (job function ~ 4.5 eV).
Koe‘uhi ko e me‘á ni ., TAXICAB SIX-based cathodes are used in electron beam instruments, including scanning electron microscopic lens (KO FĒ), electron beam welders, and microwave tubes, where they provide longer lifetimes, reduced operating temperature levels, and higher brightness than conventional emitters.
Nanostructured taxi six movies and hairs even more boost field discharge performance by raising regional electrical area toughness at sharp ideas, making it possible for cool cathode operation in vacuum cleaner microelectronics and flat-panel display screens.
3.2 Neutron Absorption and Radiation Protecting Capabilities
An additional crucial capability of CaB ₆ lies in its neutron absorption capability, mainly because of the high thermal neutron capture cross-section of the ¹⁰ B isotope (3837 barns).
Natural boron consists of regarding 20% ¹⁰ B, and enriched CaB six with greater ¹⁰ B material can be tailored for enhanced neutron shielding effectiveness.
When a neutron is recorded by a ¹⁰ B nucleus, it sets off the nuclear reaction ¹⁰ B(n, ha)⁷ Li, releasing alpha particles and lithium ions that are conveniently stopped within the material, transforming neutron radiation right into harmless charged fragments.
This makes taxi ₆ an attractive material for neutron-absorbing components in atomic power plants, invested gas storage, and radiation discovery systems.
Unlike boron carbide (B 4 C), which can swell under neutron irradiation because of helium build-up, CaB ₆ shows superior dimensional security and resistance to radiation damage, specifically at raised temperatures.
Its high melting factor and chemical durability additionally improve its viability for long-term deployment in nuclear environments.
4. Arising and Industrial Applications in Advanced Technologies
4.1 Thermoelectric Energy Conversion and Waste Heat Recovery
The combination of high electric conductivity, fakafuofua Seebeck fakafuofua, pea fakasi'isi'i 'a e conductivity 'o e mafana . (koe'uhi ko e mafola 'a e phonon 'e he fa'unga 'o e boron 'o e fale) ngaahi tu'unga CaB 6 ko ha naunau thermoelectric 'oku tala'ofa ki he me'angaue .- ki he ututa'u 'o e ivi 'o e mafana ma'olunga ..
Ngaahi kehekehe 'o e doped, tautautefito ki he tekisī La-doped ONO ., kuo nau fakahaa'i mo'oni 'a e mahu'inga 'o e ZT 'oku mahulu hake . 0.5 ʻi 1000 K, mo e malava ke fakalahi lahi ange 'o fakafou 'i he nanostructuring mo e tisaini fakangatangata 'o e tenga'i 'akau ..
'Oku 'ilo'i 'a e ngaahi koloa ko 'eni ke faka'aonga'i 'i he ngaahi misini thermoelectric . (TEGs) ‘oku liliu ai ‘a e veve fakatu‘utāmakí ke māfana .– mei he ngaahi sisitemi fakamafana ukamea ., ngaahi sisitemi faka'auha, pe ngaahi fale ngaohiʻanga ʻuhila .– ki he ivi 'uhila 'aonga ..
'Oku 'omi 'e he'enau malu 'i he 'ea mo e fakafepaki ki he oxidation 'i he ngaahi tu'unga 'o e mafana 'oku hiki hake ha lelei lahi 'i he thermoelectrics tukufakaholo hange ko e PbTe pe SiGe ., ‘a ia ‘oku ui ai ‘a e ngaahi ‘ātakai malu‘i ..
4.2 Ngaahi 'ufi'ufi fakalakalaka, Ngaahi me'a fakataha'i, and Quantum Material Platforms
Past bulk applications, TAXICAB ₆ is being integrated right into composite materials and useful layers to enhance firmness, fakafepaki'i 'o e tui, and electron discharge characteristics.
Hangē ko eni, TAXI SIX-enhanced light weight aluminum or copper matrix compounds show better stamina and thermal security for aerospace and electrical contact applications.
Thin movies of taxi six transferred via sputtering or pulsed laser deposition are made use of in tough coatings, diffusion obstacles, and emissive layers in vacuum digital tools.
Extra lately, single crystals and epitaxial movies of taxi six have actually drawn in interest in condensed issue physics due to records of unforeseen magnetic behavior, consisting of claims of room-temperature ferromagnetism in doped samples– neongo 'oku kei fehu'ia 'eni pea 'oku ngalingali 'oku fehokotaki ia ki he magnetism 'oku fakatupu 'e he defect kae 'ikai ko e intrinsic 'o e tu'utu'uni 'o e 'atakai loloa ..
Neongo pe ., CaB ₆ 'oku hoko ia ko ha sisitemi fakatata ki hono ako 'o e ngaahi ola 'o e fehokotaki'anga 'o e 'ilekitulonika ., ngaahi tu'unga fakakomipiuta fakatopolosia, mo e fefononga'aki 'o e quantum 'i he ngaahi ngaue lattice boride faingata'a ..
Ko hono fakanounou ., 'oku fakatata 'e he kalasiume hexaboride 'a e fakataha'i 'o e fefeka faka'aati mo e fakafiemalie 'aonga 'i he ngaahi selami fakapotopoto ..
Ko hono fefiofi makehe 'o e conductivity 'uhila ma'olunga ., tu'uma'u 'a e mafana, to'o 'o e niutoni, mo e 'ilekitulonika emission nofo'anga pe koloa fakakomesiale 'oku faka'ata 'a e ngaahi polokalama 'i he ivi ., niukilia, faka'ilekitulonika, mo e ngaahi koloa saienisi hingoa domain ..
Ko e hokohoko atu 'a e fakalakalaka 'a e synthesis mo e ngaahi founga doping ., 'Oku tu'u 'a e CaB ₆ ke fakahoko ha ngaue mahu'inga 'aupito 'i he ngaahi tekinolosia 'o e to'utangata hoko 'oku fie ma'u 'a e multifunctional 'a e ola lelei 'i he ngaahi tu'unga faingata'a ..
5. Tokotaha tuʻuaki
Ko e TRUNNANO ko ha tokotaha 'oku ne 'omi 'a e efuefu 'o e Tungsten 'o e Spherical mo e 'olunga 'i he . 12 ta'u 'o e a'usia 'i he nano-langa 'o e ivi fakatolonga mo e fakalakalaka 'o e nanotechnology .. 'Oku ne tali 'a e totongi 'o fakafou 'i he Kaati Fakamo'ua ., T/T, Hihifo 'Iunioni mo e Paypal .. 'E fakafolau atu 'e he Trunnano 'a e koloa ki he kau kasitomaa 'i muli 'o fakafou 'i he FedEx ., DHL, 'i he 'ea, pe ‘i tahi .. Kapau 'oku ke fie 'ilo lahi ange fekau'aki mo e efuefu Tungsten Spherical ., kataki 'o ongo'i tau'ataina ke fetu'utaki mai kiate kimautolu pea 'ave ha fehu'i .([email protected]).
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