1. I-Basic Chemistry kanye ne-Crystallographic Design ye-Boron Carbide
1.1 Ukubunjwa kwamangqamuzana kanye Nobunkimbinkimbi Besakhiwo
(I-Boron Carbide Ceramic)
I-Boron carbide (B EZINE C) ime njengenye yezinto zobumba ezithakazelisa kakhulu nezibaluleke kakhulu kwezobuchwepheshe ngenxa yenhlanganisela yayo eyingqayizivele yokuqina okunzima., ukushuba okuphansi, kanye nekhono lokumunca i-neutron eliyingqayizivele.
Ngamakhemikhali, kuyinto engeyona i-stoichiometric ngokuyinhloko eyakhiwe ngama-athomu e-boron ne-carbon, ngefomula efanelekile ye-B ₄ C, nakuba ukwakheka kwayo kwangempela kungahluka ukusuka ku-B ₄ C kuye ku-B ₁₀. EZINHLANU C, okubonisa izinhlobonhlobo ezinkulu ze-homogeneity ezibuswa ezinye izinhlelo ngaphakathi kwe-crystal lattice eyinkimbinkimbi.
Uhlaka lwekristalu lwe-boron carbide luvela ohlelweni lwe-rhombohedral (ithimba lasemkhathini u-R3̄m), ikhonjwe inethiwekhi enezinhlangothi ezintathu ze-12-atom icosahedra– amaqoqo ama-athomu e-boron– ixhunywe ngamaketanga e-C-B-C aqondile noma e-C-C eduze kwe-eksisi engunxantathu.
Lezi icosahedra, ngayinye ehlanganisa 11 ama-athomu e-boron kanye 1 i-athomu ye-carbon (B ₁₁ C), bahlanganiswe ngokuhlanganyela ne-B enamandla ngokumangalisayo– B, B– C, kanye no-C– C amabhondi, okunomthelela emandleni ayo okusebenza ahlaba umxhwele kanye nokuvikeleka okushisayo.
Ukubonakala kwalawa mayunithi e-polyhedral namaketango ahlanganayo kwethula i-anisotropy yezakhiwo kanye nezinkinga zangaphakathi., okuthinta kokubili imikhuba yemishini kanye nezindlu zedijithali zomkhiqizo.
Ngokungafani nama-porcelain alula njenge-alumina noma i-silicon carbide, Isakhiwo se-athomu se-boron carbide sivumela ukuguquguquka okukhulu kokucushwa, okwenza kube nokwenzeka ukwakheka kwesici kanye nokujikeleza kwemali okunomthelela ekusebenzeni kwayo ngaphansi kwengcindezi nokukhathazeka kanye nemisebe.
1.2 Izindawo Zokuhlala Zomzimba Nezogesi Zenzeka Ku-Atomic Bonding
Inethiwekhi ye-covalent bonding ku-boron carbide iholela kwelinye lamanani aphezulu kakhulu aqashelwa ubulukhuni phakathi kwezinto zokwenziwa.– okwesibili kuphela ku-ruby kanye ne-cubic boron nitride– ngokuvamile kusukela 30 ku 38 Isilinganiso sephoyinti lebanga kububanzi bokuqina be-Vickers.
Ubukhulu bayo bunciphe kakhulu (~ 2.52 g/cm ISITHUPHA), ukwenza nxazonke 30% ilula kune-alumina futhi icishe 70% ilula kunensimbi, inzuzo ebalulekile ezinhlelweni ezizwelayo isisindo njengesihlangu ngasinye kanye nezingxenye ze-aerospace.
I-Boron carbide ibonisa ukungabi namakhemikhali okuvelele, ukumelana nokushaywa kwama-asidi amaningi nama-antacid ezingeni lokushisa emkhathini, nakuba ingakhipha i-oxidize ngaphezulu 450 ° C emoyeni, ukwakha i-boric oxide (B ₂ O YESTHUPHA) kanye co2, okungase kuphazamise ukwethembeka kwesakhiwo kuzilungiselelo ze-oxidative yezinga lokushisa eliphezulu.
Ine-bandgap ebanzi (~ 2.1 eV), ukuyihlukanisa njenge-semiconductor enezinhlelo zokusebenza ezingaba khona kuma-electronics asezingeni lokushisa eliphezulu kanye nezitholi zemisebe.
Ngaphezu kwalokho, I-coefficient yayo ephezulu ye-Seebeck kanye nokuncishiswa kwe-thermal conductivity kuyenza ibe ikhandidethi lokuguqulwa kwamandla kagesi we-thermoelectric, ikakhulukazi ezindaweni ezinzima lapho izinto zendabuko zihluleka khona.
(I-Boron Carbide Ceramic)
Umkhiqizo futhi ubonisa ukumuncwa kwe-neutron okumangalisayo ngenxa yokubamba okuphezulu kwe-neutron kwesigaba sesiphambano se-¹⁰ B isotope (mayelana 3837 izinqolobane ze-neutron ezishisayo), ukukunikeza kubalulekile ezindongeni zokulawula i-nuclear reactor, ukuvikela, kanye nezinhlelo zendawo yokugcina igesi etshaliwe.
2. I-synthesis, Ukuphatha, kanye Nezithiyo Ekuhlanganiseni
2.1 Ukukhiqizwa Kwezimboni kanye Nezindlela Zokwakha Impushana
I-Boron carbide idalwe kakhulu ngokuncipha kwe-high-temperature carbothermal ye-boric acid (H ₃ BO ₃) noma i-boron oxide (B ₂ O EZINHLANU) ngezinsiza zekhabhoni ezifana ne-petroleum coke noma amalahle kumahitha kagesi arc agijimayo 2000 °C.
Impendulo iqhubeka ngokuthi: 2B OKUBILI O OKUBILI + 7C → B EZINE C + 6CO, okwenza amaholoholo, izimpushana ze-angular ezidinga ukugaywa okukhulu ukuze kufezeke osayizi beziqephu ezincane ze-submicron ezifanele ukuphathwa kwe-ceramic.
Eminye imizila yokuhlanganisa ihlanganisa ukuzisakaza kwe-high-temperature synthesis (I-SHS), i-laser-induced chemical vapor deposition (I-CVD), nezindlela ezisizwa nge-plasma, ezisebenzisa ukulawula okungcono phezu kwe-stoichiometry kanye ne-fragment morphology nokho azibi kangako ekusetshenzisweni kwezimboni.
Ngenxa yokuqina kwayo okukhulu, ukugaya i-boron carbide kuze kube yizimpushana ezinkulu kudla amandla futhi kusengozini yokungcoliswa yimithombo yezindaba, ukufuna ukusebenzisa izigayo ezine-boron carbide-lined noma izinsiza zokugaya ze-polymeric ukuze kugcinwe ubumsulwa.
Izimpushana eziwumphumela kufanele zihlonzwe ngokucophelela futhi zihlukaniswe ukuze kuqinisekiswe ukupakishwa okufanayo kanye nokugcotshwa okuthembekile.
2.2 Imikhawulo ye-Sintering kanye Nezindlela Zokuhlanganiswa Ezithuthukile
Ubunzima obubalulekile ekwakhiweni kwe-boron carbide ceramic ukuhlangana kwayo okuhlangene kanye ne-coefficient ephansi yokuzihlukanisa., okunciphisa kakhulu ukuminyana ngesikhathi sokuncibilika okungenangcindezi.
Futhi emazingeni okushisa asondelayo 2200 °C, i-sintering engenangcindezi ngokuvamile ikhiqiza ama-porcelain angama-80– 90% yokuqina kwezemfundo, ukushiya i-porosity eyinsalela eyehlisa amandla emishini nokusebenza kwe-ballistic.
Ukunqoba lokhu, amasu okugxilisana athuthukile njengokusunduza okushisayo (HP) kanye nokuphusha kwe-isostatic okushisayo (I-HIP) ziyasetshenziswa.
Ukuphusha okushisayo kusebenza i-uniaxial stress (ngokuvamile 30– 50 I-MPa) emazingeni okushisa phakathi 2100 ° C futhi 2300 °C, ukugqugquzela ukuhlelwa kabusha kweziqephu kanye nokuguqulwa kwepulasitiki, ukuvumela ukushuba okwedlulele 95%.
I-HIP ithuthukisa nakakhulu ukuminyana ngokusebenzisa ingcindezi yegesi ye-isostatic (100– 200 I-MPa) ngemuva kwe-encapsulation, ukususa izimbotshana ezivaliwe futhi kufinyelele ukuminyana okuseduze ngokugcwala kokuqina okuthuthukisiwe.
Izithasiselo ezifana nekhabhoni, i-silicon, noma ukushintsha amabhoridi ensimbi (isib., TIB YESIBILI, I-CrB YESIBILI) ngezinye izikhathi zethulwa ngamanani amancane ukuze kukhuliswe ukuhwebelana kanye nokuvimbela ukukhula okusanhlamvu, nakuba zinganciphisa kancane ukuqina noma ukumuncwa kahle kwe-neutron.
Naphezu kwalezi zinguquko, ubuthakathaka bomngcele wokusanhlamvu kanye nokuqina kwangaphakathi kuyaqhubeka kube yizinselele ezingapheli, ikakhulukazi ngaphansi kwezimo zokulayisha ezinamandla.
3. Izenzo Zemishini Nokusebenza Ngaphansi Kwezimo Zokulayisha Ezeqisayo
3.1 I-Ballistic Resistance kanye ne-Failure Systems
I-Boron carbide yaziwa kabanzi njengempahla yokuqala yokuvikela i-ballistic engasindi ezimbathweni zomzimba., ukufakwa kwemoto, kanye nokuvikela indiza.
Ukuqina kwayo okuphezulu kuyenza ikwazi ukuwohloka ngendlela efanele futhi ijike ama-projectile angenayo njengezinhlamvu nezicucu zokubhoboza izikhali., ukuqeda amandla e-kinetic ngamasistimu ahlanganisa i-crack, i-microcracking, kanye noshintsho lwesiteji sendawo.
Noma kunjalo, I-boron carbide ibonisa into ebizwa ngokuthi “i-amorphization ngaphansi kokushaqeka,” lapho, ngaphansi komthelela wesivinini esikhulu (ngokuvamile > 1.8 km/s), isakhiwo se-crystalline siphuka sibe yi-disordered, isigaba se-amorphous esingenawo amandla okuthwala umthwalo, okubangela ukwehluleka okudabukisayo.
Lokhu ku-amorphization okubangelwa ukucindezela, kubhekwe nge-in-situ X-ray diffraction kanye nezifundo ze-TEM, kubangwa ukuwohloka kwezinhlelo ze-icosahedral kanye namaketango e-C-B-C ngaphansi kwengcindezi ye-shear eyedlulele..
Imizamo yokunciphisa lokhu ihlanganisa ukuthuthukiswa kokusanhlamvu, isitayela esiyinhlanganisela (isib., B EZINE C-SiC), kanye nendawo engaphezulu embozwe ngezinsimbi ezithambile ukuze kubambezeleke ukwanda kokuphuka futhi kube nokuhlukana.
3.2 Gqoka Izicelo Zokumelana Nezimboni
Ukuzivikela okwedlule, ukumelana ne-boron carbide abrasion kuyenza ilungele ukusetshenziswa kwezentengiselwano kufaka phakathi ukuguga okunzima, njengemibhobho ye-sandblasting, amathiphu okusika indiza yamanzi, kanye nemidiya yokugaya.
Ukuqina kwayo kwedlula kakhulu i-tungsten carbide ne-alumina, okuholela esikhathini sokuphila eside kanye nokunciphisa izindleko zokugcina endaweni yokukhiqiza ephezulu.
Izinto ezenziwe nge-boron carbide zingasebenza ngaphansi kokugeleza kwe-abrasive yokucindezela okukhulu ngaphandle kokubhujiswa okusheshayo, nakuba ukunakekelwa kufanele kudingeke ukuvimbela ukushaqeka okushisayo kanye nokucindezeleka okuqinile phakathi nenqubo.
Ukusetshenziswa kwayo ezilungiselelweni zenuzi kufinyelela ezingxenyeni ezingagugi ezinhlelweni zokuphatha igesi, lapho ukuqina komshini kanye nokumuncwa kwe-neutron kuyadingeka kokubili.
4. Izinhlelo zokusebenza ze-Strategic ku-Nuclear, I-Aerospace, kanye ne-Emerging Technologies
4.1 I-Neutron Absorption kanye ne-Radiation Shielding Solutions
Phakathi kwezicelo ezibaluleke kakhulu ezingezona ezezempi ze-boron carbide zihlala zisemandleni e-athomu, lapho isebenza njengomkhiqizo omunca i-neutron ezigxotsheni zokulawula, ama-pellets okuvala, kanye nezakhiwo zokuvikela imisebe.
Ngenxa yengcebo ephezulu ye-isotope engu-¹⁰ B (ngokuvamile ~ 20%, nokho ingathuthukiswa ukuze > 90%), I-boron carbide ibamba kahle ama-neutron ashisayo nge-¹⁰ B(n, a)eziyisikhombisa Li impendulo, ukudala izingcezu ze-alpha nama-ion e-lithium aqukethwe kalula ngaphakathi komkhiqizo.
Lokhu kusabela akusebenzisi imisebe futhi kukhiqiza imikhiqizo emincane ehlala isikhathi eside, ukwenza i-boron carbide iphephe kakhulu futhi izinze kakhulu kunezinye izindlela ezifana ne-cadmium noma i-hafnium.
Isetshenziswa kuma-activator amanzi acindezelwe (Ama-PWR), abilayo ama-reactors amanzi (Ama-BWRs), kanye nama-activators ocwaningo, ngokuvamile ngesimo samapellets a-sintered, amashubhu agqoke, noma amaphaneli ahlanganisiwe.
Ukuzinza kwayo ngaphansi kwe-neutron irradiation kanye nekhono lokugcina imikhiqizo ye-fission ithuthukisa ukuphepha kwe-activator nokuphepha kanye nempilo ende yokusebenza.
4.2 I-Aerospace, Thermoelectrics, kanye Nemingcele Yezinto Ezizayo
Emkhathini, I-boron carbide itholwa ukuze isetshenziswe ezinhlangothini ezihamba phambili zezimoto ze-hypersonic, lapho i-high melting factor yayo (~ 2450 °C), ukushuba okuncishisiwe, futhi ukumelana nokushaqeka okushisayo kunikeza izinzuzo ngaphezu kwama-alloys ensimbi.
Amandla ayo kumagajethi we-thermoelectric avela ku-coefficient yayo ephezulu ye-Seebeck kanye nokuncishiswa kokushisa okushisayo., okuvumela ukuguqulwa okuqondile kokufudumala kwemfucuza kube amandla kagesi ezindaweni ezinzima ezifana nama-deep-space probes noma amasistimu anamandla enuzi.
Ucwaningo luyaqhubeka nokusungula izinhlanganisela ezisuselwe ku-boron carbide nama-carbon nanotubes noma i-graphene ukuze kuthuthukiswe ukuqina kanye nokusebenza kukagesi kuma-elekthronikhi wezakhiwo ezisebenzayo..
Ngaphezu kwalokho, izakhiwo zayo ze-semiconductor ziyasetshenziswa kumayunithi okuzwa okuqiniswe emisebeni nasezimbonini zendawo kanye nezicelo zenuzi..
Ngokufingqa, I-boron carbide porcelain imelela isisekelo sezinto ezitholakala lapho kuhlangana khona ukusebenza kahle kwemishini ngokwedlulele, umklamo wenuzi, kanye nokukhiqizwa okuthuthukile.
Ingxube yayo yohlobo olulodwa yokuqina okuphezulu kakhulu, ukushuba okuncishisiwe, kanye nekhono lokumunca i-neutron kuyenza ingenakuthathelwa indawo kwezokuvikela kanye nobuchwepheshe besimanje benuzi, kuyilapho ucwaningo oluqhubekayo luhlala lunweba amandla alo ngqo emkhathini, ukuguqulwa kwamandla, kanye nezinhlanganisela zesizukulwane esilandelayo.
Njengoba amasu okucwenga ekhula futhi kuvela imiklamo emisha eyinhlanganisela, I-boron carbide ngokuqinisekile izohlala isemaphethelweni aphambili wokuqamba izinto ezintsha ngezithiyo ezidinga kakhulu zobuchwepheshe..
5. Umsabalalisi
I-Advanced Ceramics yasungulwa ngo-Okthoba 17, 2012, yibhizinisi lobuchwepheshe obuphezulu elizinikele ocwaningweni nasekuthuthukisweni, ukukhiqiza, ukucubungula, ukuthengisa kanye nezinsizakalo zobuchwepheshe zezinto eziphathelene ne-ceramic nemikhiqizo. Imikhiqizo yethu ihlanganisa kodwa ingagcini nje nge-Boron Carbide Ceramic Products, I-Boron Nitride Ceramic Products, Imikhiqizo ye-Silicon Carbide Ceramic, Imikhiqizo ye-Silicon Nitride Ceramic, I-Zirconium Dioxide Ceramic Products, njll. Uma unentshisekelo, sicela ukhululeke ukuxhumana nathi.([email protected])
Omaka: I-Boron Carbide, I-Boron Ceramic, I-Boron Carbide Ceramic
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