1. I-Basic Chemistry kanye ne-Crystallographic Design ye-Taxi SIX
1.1 I-Boron-Rich Framework kanye ne-Electronic Band Framework
(I-Calcium Hexaboride)
I-calcium hexaboride (TAXI ₆) i-stoichiometric metal boride evela enkambweni ye-rare-earth kanye ne-alkaline-earth hexaboride, ihlukaniswa ngengxube yayo eyodwa ye-ionic, covalent, kanye nezimfanelo metallic bonding.
Isakhiwo sayo sekristalu samukela i-cubic CsCl-type lattice (iqembu lesikhala Pm-3m), lapho ama-athomu e-calcium ehlala khona emaphethelweni e-cube kanye nohlaka oluyinkimbinkimbi lwezinhlangothi ezintathu ze-boron octahedra (B ₆ amadivayisi) uhlala esikhungweni somzimba.
I-boron octahedron ngayinye yakhiwe ama-athomu e-boron ayisithupha anamathela ngokuhlanganyela ekuhlelweni kokulinganisa okukhulu., ukudala okuqinile, inethiwekhi engenawo ama-electron esekelwa ukudluliswa kwezindleko kusuka ku-athomu ye-electropositive calcium.
Lokhu kudlulisa izindleko kuholela ebhendini yokudlulisela elayishwe kancane, inika itekisi isithupha nge-conductivity kagesi ephezulu ngokungavamile yomkhiqizo we-ceramic– ngokohlelo lwe 10 ⁵ S/m kuleveli yezinga lokushisa legumbi– naphezu kwe-bandgap yayo enkulu ecishe ibe ngu-1.0– 1.3 I-eV njengoba isungulwe yizifundo zocwaningo lokumuncwa kanye ne-photoemission.
Ukuqala kwale mfihlakalo– conductivity ephezulu ekhona ngapha nangapha nge-bandgap enkulu– bekuyindaba yocwaningo olunzulu, ngemiqondo ephakamisa ukubonakala kwezimo zamaphutha angaphakathi, i-surface conductivity, noma izindlela ze-polaronic conduction ezihlanganisa ukuhlanganisa kwe-electron-phonon yendawo.
Izibalo zakamuva zezimiso zokuqala zisekela idizayini lapho ubuncane bebhendi yokudlulisela itholwa kakhulu kuma-orbitals e-Ca 5d, kuyilapho ibhendi ye-valence ibuswa yizifunda ze-B 2p, ukukhiqiza i-slim, i-dispersive band ekhuthaza ukunyakaza kwe-electron.
1.2 Ukuphepha Okushisayo Nemishini Ezindabeni Ezidlulele
Njenge-ceramic refractory, I-TAXICAB ₆ ibonisa ukuzinza okushisayo okungavamile, ngephuzu lokuncibilika elidlulayo 2200 ° C kanye nokuncipha kwesisindo okunganaki kuzilungiselelo ze-inert noma zokuhlanza i-vacuum kuze kufike 1800 °C.
Izinga layo lokushisa eliphezulu lokuhlakazeka kanye nomfutho we-vapor oncishisiwe kuyenza ifaneleke ekwakhiweni kwezinga lokushisa eliphezulu nezinhlelo zokusebenza ezingokoqobo lapho ukwethembeka okuphathekayo ngaphansi kokukhathazeka okushisayo kubalulekile..
Ngomshini, I-CaB ₆ inokuqina kwe-Vickers okulinganiselwa ku-25– 30 I-GPa, ukuyibeka phakathi kwe-boride eyaziwa kakhulu futhi ikhombisa amandla e-B– B amabhondi e-covalent ngaphakathi kohlaka lwe-octahedral.
Okubalulekile futhi kubonisa i-coefficient ephansi yokunwetshwa kwe-thermal (~ 6.5 × 10 ⁻⁶/ K), okunomthelela ekumelaneni nokushaqeka okushisayo okuvelele– ikhwalithi ebalulekile yezingxenye ezisuselwe ekushisiseni okusheshayo nemijikelezo yokupholisa.
Lezi zakhiwo zokuhlala, kuhlanganiswe nokungangeni kwamakhemikhali ezinsimbi ezincibilikisiwe nama-slags, isekela ukusetshenziswa kwayo kuma-crucibles, ama-thermocouple sheaths, kanye namayunithi okuzwa izinga lokushisa eliphezulu ezindaweni zokucubungula i-metallurgical kanye nezimboni.
( I-Calcium Hexaboride)
Ngaphezu kwalokho, I-TAXICAB ₆ yembula ukumelana ne-oxidation okukhethekile okubalwe ngezansi 1000 °C; nokho, ngaphezu kwalo mkhawulo, ukufakwa kwe-oxidation yendawo ku-calcium borate ne-boric oxide kungenzeka, idinga ukuqedwa kokuvikela noma izilawuli zokusebenza kuma-ambiences oxidizing.
2. I-Synthesis Pathways kanye ne-Microstructural Design
2.1 Amasu Okwenziwa Okujwayelekile Nethuthukile
I-synthesis ye-high-purity taxi six ngokuvamile ihlanganisa izimpendulo zesimo esiqinile phakathi kwe-calcium ne-boron precursors emazingeni okushisa aphakeme..
Izindlela ezijwayelekile zihlanganisa ukuncipha kwe-calcium oxide (I-CaO) nge-boron carbide (B ₄ C) noma i-boron ebalulekile ngaphansi kwezimo ze-inert noma ze-vacuum emazingeni okushisa phakathi 1200 ° C futhi 1600 °C. ^
. Impendulo kufanele ilawulwe kahle ukuze kugwenywe ukwakheka kwezigaba ezengeziwe njenge-taxicab four noma i-taxicab TWO., okungase konakalise ukusebenza kukagesi kanye nemishini.
Amanye amasu ahlanganisa ukwehla kwe-carbothermal, ukuncibilika kwe-arc, kanye nokuhlanganiswa kwe-mechanochemical kusetshenziswa ukugaya ibhola elinamandla amakhulu, okunganciphisa amazinga okushisa okuphendula futhi kukhulise i-powder homogeneity.
Okwezingxenye eziminyene ze-ceramic, Sintering izindlela ezifana nokucindezela okushisayo (HP) noma uqalise ukucwiliswa kwe-plasma (I-SPS) zisetshenziselwa ukufeza ukuminyana okucishe kufane nethiyori ngenkathi kuncipha ukukhula okusanhlamvu nokugcina ama-microstructures amakhulu.
I-SPS, ngokuqondile, kwenza kube nokwenzeka ukuhlanganiswa okusheshayo emazingeni okushisa aphansi kanye nezikhathi zokuhlala ezimfushane, ukunciphisa ingozi ye-calcium volatilization kanye nokugcina i-stoichiometry.
2.2 I-Doping ne-Issue Chemistry Yokulungiswa Kwekhaya
Okunye okuqhamuke kakhulu ocwaningweni lwe-CaB ₆ kube yikhono lokuhlanganisa izindawo zokuhlala zedijithali neze-thermoelectric noma ezohwebo nge-doping yamabomu nobunjiniyela obunamaphutha..
Ukushintsha i-calcium nge-lanthanum (I), i-cerium (Ce), noma ezinye izici zomhlaba eziyivelakancane zethula abahlinzeki benkokhelo eyengeziwe, kuthuthukisa kakhulu ukuqhutshwa kukagesi nokwenza kube nokwenzeka ezenzweni zohlobo lwe-n-thermoelectric.
Ngokufanayo, ukubuyisela ingxenye ye-boron ngekhabhoni noma i-nitrogen kungenza ngokwezifiso ukujiya kwezifunda eduze nezinga le-Fermi, ithuthukisa i-coefficient ye-Seebeck kanye nenani eliphelele le-thermoelectric yenani (ZT).
Izinkinga zemvelo, ikakhulukazi imisebenzi ye-calcium, futhi ukudlala umsebenzi obalulekile ekunqumeni conductivity.
Ucwaningo lukhombisa ukuthi amatekisi ayisithupha ajwayele ukukhombisa ukushoda kwe-calcium ngenxa yokuguquguquka ngesikhathi sokuphatha izinga lokushisa eliphezulu, okuholela ekuqhutshweni kwemigodi kanye nezenzo zohlobo lwe-p kwamanye amasampuli.
Ukulawula i-stoichiometry ngokulawula okunembile kwe-ambience kanye ne-encapsulation ngesikhathi sokuhlanganiswa kungenxa yaleso sizathu kubalulekile ekusebenzeni kahle okuphindaphindekayo ezinhlelweni zokuguqulwa kwedijithali namandla..
3. Izakhiwo Ezisebenzayo kanye Nombono Womzimba Etekisini ₆
3.1 Izicelo Ezikhethekile Zokukhipha I-Electron kanye Nezinkambu Zokukhipha
I-CaB ₆ idume ngomsebenzi wayo ophansi– cishe 2.5 eV– phakathi kwezinto ezithengekayo kakhulu zemikhiqizo ye-ceramic engashintshi– okwenza kube ikhandidethi elikhethekile le-thermionic kanye ne-electron emitters yendawo.
Le ndawo yokuhlala noma yezohwebo ivela ekuxubeni kokugxilwa kwe-electron ephezulu kanye nokuhlelwa kwe-dipole yangaphezulu enenzuzo, ukunika amandla ukukhishwa kwama-electron asebenzayo emazingeni okushisa ancishisiwe ngokufanelekile uma kuqhathaniswa nemikhiqizo evamile efana ne-tungsten (umsebenzi ~ 4.5 eV).
Ngenxa yalokhu, I-TAXICAB SIX-based cathodes isetshenziswa kumathuluzi we-electron beam, okuhlanganisa ukuskena ilensi ye-electron microscopic (YILUPHI), ama-electron beam welders, kanye namashubhu e-microwave, lapho zinikeza ukuphila okude, amazinga okushisa okusebenza ancishisiwe, nokukhanya okuphezulu kunama-emitters avamile.
Itekisi ehlelekile amamuvi ayisithupha nezinwele kuthuthukisa ukusebenza kokukhishwa kwenkundla ngokuphakamisa ukuqina kwendawo kagesi emibonweni ebukhali., okwenza kube lula ukusebenza kwe-cathode ku-vacuum cleaner microelectronics kanye nezikrini zokubonisa zephaneli eliyisicaba.
3.2 I-Neutron Absorption kanye Namakhono Okuvikela Imisebe
Amandla engeziwe abalulekile e-CaB ₆ asemandleni ayo okumunca i-neutron, ikakhulukazi ngenxa ye-thermal neutron yokuthwebula ingxenye enqamulayo ye-¹⁰ B isotope (3837 izinqolobane).
I-boron yemvelo iqukethe mayelana 20% ¹⁰ B, kanye ne-CaB six ethuthukisiwe ngezinto ezinkulu ezingu-¹⁰ B ingalungiselelwa ukusebenza kahle kokuvikela i-neutron.
Uma i-neutron irekhodwa yi-nucleus engu-¹⁰ B, iqala ukusebenza kwe-nuclear ¹⁰ B(n, a)⁷ Li, ukukhulula izinhlayiya ze-alpha nama-ion e-lithium amiswa kalula ngaphakathi kwempahla, ukuguqula imisebe ye-neutron ibe yizicucu ezingenabungozi.
Lokhu kwenza itekisi ₆ into ekhangayo yezingxenye ezimunca i-neutron ezitshalweni zamandla e-athomu., isitoreji segesi esitshaliwe, kanye nezinhlelo zokutholwa kwemisebe.
Ngokungafani ne-boron carbide (B ₄ C), engavuvukala ngaphansi kwe-neutron irradiation ngenxa yokwakheka kwe-helium, I-CaB ₆ ikhombisa ukuvikeleka okuphezulu kobukhulu nokumelana nokulimala kwemisebe, ikakhulukazi emazingeni okushisa aphakeme.
Isici sayo esiphezulu sokuncibilika kanye nokuqina kwamakhemikhali ngaphezu kwalokho kuthuthukisa ukusebenza kwayo ukuze isetshenziswe isikhathi eside ezindaweni zenuzi..
4. Izicelo ezikhulayo nezimboni ku-Advanced Technologies
4.1 Ukuguqulwa kwamandla kagesi we-Thermoelectric kanye nokubuyiswa kokushisa kwe-Waste
Inhlanganisela high conductivity kagesi, i-coefficient ye-Seebeck emaphakathi, futhi kuncishiswe ukuqhutshwa kwe-thermal (ngenxa yokusatshalaliswa kwephonon ngohlaka lwesakhiwo se-boron) izilungiselelo CaB ₆ njengento ethembisayo ye-thermoelectric yamathuluzi- ekutholeni amandla okushisa aphezulu.
Izinhlobonhlobo ezifakiwe, ikakhulukazi La-doped itekisi ESITHUPHA, empeleni bakhombise amanani e-ZT edlula 0.5 kwe 1000 K, ngomthamo wokuthuthukiswa okwengeziwe nge-nanostructuring kanye nomklamo womkhawulo wokusanhlamvu.
Le mikhiqizo itholwa ukuze isetshenziswe kumajeneretha kagesi we-thermoelectric (Ama-TEG) eziguqula imfucuza eyingozi ifudumale– kusuka kumasistimu okushisa ensimbi, amasistimu wokuqeda, noma izitshalo zikagesi– emandleni kagesi awusizo.
Ukuvikeleka kwabo emoyeni kanye nokumelana ne-oxidation emazingeni okushisa aphakanyisiwe kunikeza inzuzo enkulu ngaphezu kwe-thermoelectrics evamile njenge-PbTe noma i-SiGe, okudinga umoya ovikelayo.
4.2 Izembatho Ezithuthukile, Izinhlanganisela, kanye nama-Quantum Material Platforms
Izinhlelo zokusebenza eziyinqwaba ezedlule, I-TAXICAB ₆ ihlanganiswa ngqo ezintweni eziyinhlanganisela kanye nezendlalelo eziwusizo ukuze kuthuthukiswe ukuqina, ukumelana nokugqoka, kanye nezici zokukhishwa kwe-electron.
Ngokwesibonelo, I-TAXI SIX yesisindo sokukhanya esithuthukisiwe i-aluminium noma izinhlanganisela zethusi ze-matrix zibonisa amandla angcono nokuphepha okushisayo kwe-aerospace nezinhlelo zokusebenza zokuxhumana zikagesi..
Amafilimu azacile amatekisi ayisithupha adluliswa nge-sputtering noma nge-pulsed laser deposition asetshenziswa embotsheni eqinile., izithiyo zokusabalalisa, kanye nezendlalelo ezikhishwayo kumathuluzi edijithali ye-vacuum.
Okungeziwe kamuva nje, Ikristalu eyodwa namamuvi we-epitaxial wamatekisi ayisithupha empeleni ahehe intshisekelo kundaba efingqiwe ye-physics ngenxa yamarekhodi okuziphatha kazibuthe okungalindelekile., okubandakanya izimangalo ze-ferromagnetism yezinga lokushisa legumbi kumasampuli ane-doped– nakuba lokhu kuqhubeka nokungabaza futhi okungenzeka kuxhumene ne-defect-induced magnetism esikhundleni sokuhleleka kwangaphakathi kwebanga elide.
Akunandaba, I-CaB ₆ isebenza njengohlelo lwemodeli yokufunda imiphumela yokuxhuma ama-electron, izimo zedijithali ze-topological, kanye nokuhamba kwe-quantum kuma-boride latticeworks ayinkimbinkimbi.
Ngokufigqiwe, I-calcium hexaboride iyisibonelo sokuhlangana kokuqina kwezakhiwo kanye nokusebenziseka kalula kwezitsha zobumba eziyinkimbinkimbi..
Ingxube yayo eyingqayizivele ye-conductivity kagesi ephezulu, ukuzinza okushisayo, ukumuncwa kwe-neutron, kanye nezindawo zokuhlala noma ezohwebo ze-electron zivumela izinhlelo zokusebenza kuwo wonke amandla, zenuzi, electronic, namagama esizinda sesayensi yemikhiqizo.
Njengoba amasu okuhlanganisa kanye ne-doping eqhubeka nokuthuthuka, I-CaB ₆ ibekwe esikhundleni sokudlala umsebenzi obaluleke kakhulu kubuchwepheshe besizukulwane esilandelayo obudinga ukusebenza kahle kwemisebenzi eminingi ngaphansi kwezimo ezinzima..
5. Umphakeli
U-TRUNNO ungumphakeli we-Spherical Tungsten Powder ene-over 12 Iminyaka yokuhlangenwe nakho kwe-nano-building energy ukongiwa kanye nokuthuthukiswa kwe-nanotechnology. Yamukela inkokhelo ngekhadi lesikweletu, T/T, I-West Union ne-Paypal. I-Trunnano izothumela izimpahla kumakhasimende aphesheya kwezilwandle nge-FedEx, I-DHL, ngomoya, noma ngolwandle. Uma ufuna ukwazi okwengeziwe nge-Spherical Tungsten Powder, sicela ukhululeke ukuxhumana nathi futhi uthumele uphenyo([email protected]).
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