1. Kemika Kumu a me ka Hoʻolālā Crystallographic o ka Taxi EONO
1.1 Pākuʻi Boron-Rich a me Electronic Band Framework
(Kalsium Hexaboride)
Calcium hexaboride (TAXI ₆) is a stoichiometric metal boride coming from the course of rare-earth and alkaline-earth hexaborides, distinguished by its one-of-a-kind mix of ionic, covalent, and metallic bonding qualities.
Its crystal structure adopts the cubic CsCl-type lattice (space group Pm-3m), where calcium atoms inhabit the cube edges and a complex three-dimensional framework of boron octahedra (B ₆ devices) stays at the body facility.
Each boron octahedron is composed of six boron atoms covalently adhered in a highly symmetric arrangement, creating a rigid, electron-deficient network supported by cost transfer from the electropositive calcium atom.
This cost transfer leads to a partially loaded transmission band, endowing taxi six with unusually high electrical conductivity for a ceramic product– on the order of 10 ⁵ S/m ma ka pae wela o ka lumi– ʻoiai ʻo kāna bandgap nui ma kahi o 1.0– 1.3 eV e like me ka mea i hoʻokumu ʻia e nā noiʻi noiʻi optical absorption a me photoemission.
Ka hoomaka ana o keia pohihihi– kiʻekiʻe conductivity ʻaoʻao ʻaoʻao me kahi bandgap nui– ua lilo i kumuhana o ka noiʻi nui, me nā manaʻo e hōʻike ana i ka ʻike ʻia o nā mokuʻāina intrinsic flaw, conductivity ili, a i ʻole nā hana hoʻokele polaronic me ka hoʻohui ʻana i ka electron-phonon kūloko.
Hoʻomau nā helu kumu mua hou i kahi hoʻolālā e loaʻa nui ai ka liʻiliʻi loa mai nā orbital Ca 5d., ʻoiai ʻo ka hui valence e hoʻomalu ʻia e nā mokuʻāina B 2p, e hana ana i ka lohi, pūʻali puʻupuʻu e hoʻoikaika i ka neʻe electron.
1.2 Palekana Thermal a me Mechanical i nā pilikia koʻikoʻi
E like me ka ceramic refractory, Hōʻike ʻo TAXICAB ₆ i ke kūpaʻa wela kupaianaha, me kahi helu hehee i oi aku 2200 ° C a me ka pohō kaumaha ʻole ma nā hoʻonohonoho hoʻomaʻemaʻe inert a i ʻole 1800 ° C.
ʻO kona wela hoʻoheheʻe kiʻekiʻe a me ka hoʻohaʻahaʻa ʻana i ka mahu ua kūpono ia no ka hale kiʻekiʻe kiʻekiʻe a me nā noi kūpono kahi mea nui ka ʻoiaʻiʻo ma lalo o ka hopohopo wela..
Me ka mīkini, Loaʻa iā CaB ₆ kahi paʻa Vickers ma kahi o 25– 30 GPa, hoʻonoho iā ia i waena o nā boride paʻakikī loa a e hōʻike ana i ka ikaika o ka B– ʻO nā paʻa kovalent B i loko o ke kāʻei octahedral.
Hōʻike pū ka mea i kahi koena haʻahaʻa o ka hoʻonui wela (~ 6.5 × 10 ⁻⁶/ K), e hāʻawi ana i ke kūpaʻa haʻalulu wela– he ʻano koʻikoʻi no nā ʻāpana e pili ana i ka hoʻomehana wikiwiki a me ka hoʻoilo.
ʻO kēia mau hale noho, hui pū ʻia me ka inertness kemika e pili ana i nā kila hoʻoheheʻe a me nā palaka, kākoʻo i kona hoʻohana ʻana i nā crucibles, nā pūʻulu thermocouple, a me nā ʻāpana ʻike wela kiʻekiʻe i loko o nā kaiapuni metala a me nā ʻoihana ʻenehana.
( Kalsium Hexaboride)
Eia kekahi, Hōʻike ʻo TAXICAB ₆ i ke kūʻē kūʻokoʻa i ka oxidation i helu ʻia ma lalo nei 1000 ° C; akā naʻe, maluna o keia palena, Hiki ke ho'ohehe'e 'ia ka ili i ka calcium borate a me ka boric oxide, e koi ana i nā hoʻopau pale a i ʻole nā mana hana i ka hoʻonā ʻana.
2. ʻO nā ala Synthesis a me ka Hoʻolālā Microstructural
2.1 Nā ʻenehana hana maʻamau a kiʻekiʻe
ʻO ka synthesis o ka taxi hoʻomaʻemaʻe kiʻekiʻe ʻeono maʻamau e loaʻa i nā pane kūlana paʻa i waena o ka calcium a me ka boron precursors i nā wela kiʻekiʻe..
ʻO nā ala maʻamau ka emi ʻana o ka calcium oxide (CaO) me ka boron carbide (B ₄ C) a i ʻole ka boron koʻikoʻi ma lalo o nā kūlana inert a i ʻole nā māmā ma nā pae wela ma waena 1200 ° C a 1600 ° C. ^
. Pono e hoʻoponopono maikaʻi ʻia ka pane e pale aku i ka hoʻokumu ʻia ʻana o nā hana hou e like me ka taxicab ʻehā a i ʻole ka taxicab TWO., hiki ke hōʻino i ka hana uila a me ka mechanical.
ʻO nā ʻenehana ʻē aʻe ka hoʻemi ʻana o ka carbothermal, arc-melting, a me ka mechanochemical synthesis me ka hoʻohana ʻana i ka wili pōlele kiʻekiʻe, hiki ke hoʻemi i nā pae wela o ka pane a hoʻonui i ka homogeneity pauka.
No nā ʻāpana seramika paʻa, nā ʻano hana hoʻopaʻa ʻana e like me ke kaomi wela (HP) a i ʻole e hoʻoulu i ka sintering plasma (SPS) Hoʻohana ʻia ia e hoʻokō i ka nui o ka manaʻo ʻoiai e hoʻemi ana i ka ulu ʻana o ka palaoa a mālama i nā microstructure nui.
SPS, kikoʻī, hiki ke hoʻohui wikiwiki i nā mahana haʻahaʻa a me nā manawa noho pōkole, e hoʻemi ana i ka pilikia o ka volatilization calcium a me ka mālama ʻana i ka stoichiometry.
2.2 ʻO ka Doping a me ka hoʻopuka kemika no ka hoʻoponopono ʻana i ka home
ʻO kekahi o nā mea nui loa i ka noiʻi noiʻi ʻo CaB ₆ ʻo ia ka hiki ke hoʻoponopono i kāna mau hale kikohoʻe a thermoelectric a i ʻole nā mea kūʻai aku me ka doping i manaʻo ʻia a me ka ʻenehana flaw..
Hoʻololi i ka calcium me ka lanthanum (ʻO ka), cerium (ʻO Ce), a i ʻole nā mea ʻokoʻa ʻē aʻe e hoʻolauna i nā mea hoʻolako uku, hoʻonui nui i ka conductivity uila a hiki ke hana i nā hana thermoelectric n-type.
Pēlā nō, Hiki ke hoʻololi i ka ʻāpana o ka boron me ke kalapona a i ʻole ka nitrogen ke hana i ka mānoanoa o nā mokuʻāina kokoke i ka pae Fermi, hoʻonui i ka helu Seebeck a me ka helu thermoelectric holoʻokoʻa o ka waiwai (ZT).
Nā pilikia pili, ʻoi aku ka hana calcium, pāʻani pū kekahi hana koʻikoʻi i ka hoʻoholo ʻana i ka conductivity.
Hōʻike nā noiʻi noiʻi e hōʻike pinepine ana ka taxi ʻeono i ka nele o ka calcium ma muli o ka volatilization i ka mālama ʻana i ka wela kiʻekiʻe, alakaʻi i ka hole conduction a me ka p-type hana i kekahi mau laʻana.
ʻO ka hoʻoponopono ʻana i ka stoichiometry ma o ka mana ambience pololei a me ka encapsulation i ka wā synthesis no ia kumu koʻikoʻi no ka hana hou ʻana i nā noi uila a me ka hoʻololi mana..
3. Nā Pono Pono a me ka Phantasm Kino ma ka Taxi ₆
3.1 Hoʻokuʻu Electron Kūʻokoʻa a me nā noi hoʻokuʻu kahua
Kaulana ʻo CaB ₆ no kāna hana haʻahaʻa haʻahaʻa– ʻākeʻakeʻa 2.5 eV– i waena o nā mea kūʻai aku no nā huahana seramika paʻa– e hoʻolilo iā ia i moho kūikawā no ka thermionic a me nā emitters electron area.
Loaʻa kēia hale noho a ʻoihana pāʻoihana mai ka hui ʻana o ka ʻike electron kiʻekiʻe a me ka hoʻonohonoho dipole surface pono., hiki i ka hoʻokuʻu electron kūpono i nā pae wela i hoʻemi ʻia i hoʻohālikelike ʻia me nā huahana maʻamau e like me tungsten (hana hana ~ 4.5 eV).
Ma muli o kēia, Hoʻohana ʻia nā cathodes e pili ana i ka TAXICAB SIX i nā mea kani uila, me ka nānā ʻana i nā lens microscopic electron (KA MEA), mea welder kukuna electron, a me nā paipu microwave, kahi e hāʻawi ai lākou i nā manawa lōʻihi, hōʻemi ʻia nā pae wela hana, a ʻoi aku ka ʻōlinolino ma mua o nā mea hoʻopuka maʻamau.
ʻEono kiʻiʻoniʻoni a me nā lauoho Nanostructured ʻoi aku ka hoʻonui ʻana i ka hana hoʻokuʻu ʻana o ke kahua ma o ka hoʻonui ʻana i ka paʻakikī o ka ʻāpana uila i nā manaʻo koi., hiki ke hana i ka cathode maʻalili i loko o ka mīkini hoʻomaʻemaʻe hoʻomaʻemaʻe microelectronics a me nā pale hōʻike pālahalaha.
3.2 ʻO ka Neutron Absorption and Radiation Protection Capability
Aia kekahi mana koʻikoʻi o CaB ₆ i kona hiki ke hoʻoemi neutron, ma muli o ke kiʻekiʻe o ka neutron wela kiʻekiʻe i ka ʻāpana o ka ¹⁰ B isotope (3837 hale papaa).
ʻO ka boron kūlohelohe e pili ana 20% ¹⁰ B, a hoʻonui ʻia ʻo CaB ʻeono me nā mea ¹⁰ B nui aʻe hiki ke hoʻopili ʻia no ka hoʻonui ʻana i ka pono pale pale neutron..
Ke hoʻopaʻa ʻia kahi neutron e kahi nucleus ¹⁰ B, Hoʻopau ia i ka hopena nuklea ¹⁰ B(n, a)⁷ Li, ka hoʻokuʻu ʻana i nā ʻāpana alpha a me nā ion lithium i hoʻopaʻa pono ʻia i loko o ka mea, ka hoʻololi ʻana i ka radiation neutron i mau ʻāpana i hoʻopaʻa ʻia.
Hoʻolilo kēia i ka taxi ₆ i mea nani no nā ʻāpana hoʻopaʻa neutron i nā mea kanu mana atomika, waihona kinoea hoʻopukapuka, a me nā ʻōnaehana ʻike radiation.
ʻAʻole like me ka boron carbide (B ₄ C), hiki ke pehu ma lalo o ka neutron irradiation ma muli o ke kūkulu ʻana o ka helium, Hōʻike ʻo CaB ₆ i ka palekana nui a me ka pale ʻana i ka pōʻino radiation, kikoʻī i nā mahana hoʻokiʻekiʻe.
ʻO kāna kumu hoʻoheheʻe kiʻekiʻe a me ka lōʻihi o ka kemika e hoʻomaikaʻi hou i kona hiki ke hoʻokau lōʻihi i nā kaiapuni nuklea..
4. Nā noi e kū ana a me nā ʻenehana i nā ʻenehana kiʻekiʻe
4.1 ʻO ka hoʻololi ʻana i ka ikehu Thermoelectric a me ka hoʻihoʻi ʻana i ka wela ʻōpala
ʻO ka hui pū ʻana o ka conductivity uila kiʻekiʻe, ka helu Seebeck haʻahaʻa, a me ka hoemi ana i ka wela (ma muli o ka laha ʻana o ka phonon e ka hale hana boron) hoʻonohonoho iā CaB ₆ ma ke ʻano he mea thermoelectric hoʻohiki no ka mea hana- i ka ʻohi ikehu wela kiʻekiʻe.
Nā ʻano like ʻole doped, ʻoi aku ka La-doped taxi SIX, ua hōʻike maoli i ka waiwai o ZT 0.5 ma 1000 K, me ka hiki ke hoʻonui hou aku ma o ka nanostructuring a me ka hoʻolālā palena palaoa.
Ke ʻike ʻia nei kēia mau huahana no ka hoʻohana ʻana i nā mea hana thermoelectric (Nā TEG) e hoʻolilo i ka ʻōpala pōʻino mehana– mai nā ʻōnaehana hoʻomehana kila, ʻōnaehana hoʻopau, a i ʻole nā mea kanu mana– i ka mana uila pono.
ʻO kā lākou palekana i ka ea a me ke kūpaʻa ʻana i ka oxidation i nā pae wela e hāʻawi i kahi pōmaikaʻi nui ma mua o nā thermoelectrics kahiko e like me PbTe a i ʻole SiGe., e kāhea ana i nā lewa pale.
4.2 Nā Paʻi Kiʻekiʻe, Huipuia, a me nā Pāhana Mea Kuantum
Nā noi nui i hala, Hoʻohui ʻia ʻo TAXICAB ₆ i loko o nā mea i hoʻohui ʻia a me nā papa pono e hoʻonui ai i ka paʻa, ʻaʻahu kūʻē, a me nā hiʻohiʻona hoʻokuʻu electron.
ʻo kahi laʻana, ʻO TAXI SIX i hoʻonui ʻia i ka alumini māmā a i ʻole nā pūhui copper matrix e hōʻike ana i ka ʻoi aku ka maikaʻi o ka ikaika a me ka palekana wela no ka aerospace a me nā noi pili uila..
Hoʻohana ʻia nā kiʻiʻoniʻoni lahilahi o ka taxi ʻeono i hoʻoili ʻia ma o ka sputtering a i ʻole pulsed laser deposition i hoʻohana ʻia i loko o nā pale paʻakikī., nā pilikia hoʻolaha, a me nā papa emissive i loko o nā mea hana kikohoʻe vacuum.
Keu aku nei, ʻO nā kristal hoʻokahi a me nā kiʻiʻoniʻoni epitaxial o ka taxi ʻeono ua huki maoli i ka hoihoi i ka physics hoʻopuka condensed ma muli o nā moʻolelo o ka ʻano hana magnetic i manaʻo ʻole ʻia., i loko o nā koi o ka ferromagnetism wela lumi i nā laʻana doped– ʻoiai ke hoʻomau nei kēia i ka nīnau a pili paha i ka magnetism defect-induced ma kahi o ka intrinsic long-long order..
He mea ʻole, He ʻōnaehana kumu hoʻohālike ʻo CaB ₆ no ke aʻo ʻana i nā hopena pili uila, nā kūlana kikohoʻe topological, a me ka lawe ʻana i ka quantum i nā latticeworks boride paʻakikī.
Ma ka hōʻuluʻulu, ʻO ka calcium hexaboride e hōʻike ana i ka hoʻohui ʻana o ka paʻakikī o ke kūkulu hale a me ka ʻoluʻolu kūpono i nā seramika maʻemaʻe..
ʻO kāna hui kūikawā o ka conductivity uila kiʻekiʻe, paʻa wela, hoʻomoʻo neutron, a me ka electron hoʻokuʻu ʻana i nā hale noho a i ʻole nā mea pāʻoihana e hiki ai i nā noi ma waena o ka ikehu, nukelea, uila uila, a me nā inoa ʻepekema huahana.
Ke hoʻomau nei nā hoʻolālā synthesis a me doping, Hoʻonohonoho ʻia ʻo CaB ₆ e pāʻani i kahi hana koʻikoʻi i nā ʻenehana hou e pono ai ka pono multifunctional ma lalo o nā kūlana koʻikoʻi..
5. Mea hoolako
ʻO TRUNNANO kahi mea hoʻolako o Spherical Tungsten Powder me ka ʻoi aku 12 mau makahiki o ka ʻike i ka mālama ʻana i ka ikehu kūkulu nano a me ka hoʻomohala ʻana i ka nanotechnology. ʻAe ia i ka uku ma o Kāleka Kāleka, T/T, West Union a me Paypal. E hoʻouna aku ʻo Trunnano i nā waiwai i nā mea kūʻai aku ma waho ma o FedEx, DHL, ma ka lewa, a ma ke kai paha. Inā makemake ʻoe e ʻike hou aku e pili ana i ka Spherical Tungsten Powder, eʻoluʻolu e leka uila iā mākou a hoʻouna i kahi nīnau([email protected]).
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