1. ʻO ke Kemika Kumu a me ka Hoʻolālā Crystallographic o Boron Carbide
1.1 Ka Hoʻohui Molecular a me ka Paʻakikī Hoʻolālā
(ʻO Boron Carbide Ceramic)
Boron carbide (B EHA C) ke kū nei ʻo ia kekahi o nā mea seramika koʻikoʻi loa a me ka ʻenehana ma muli o kāna hui kūʻokoʻa o ka paʻa paʻa., mānoanoa haʻahaʻa, a me ka mana o ka neutron absorption.
Ma kemika, he mea non-stoichiometric i hana mua ia me ka boron a me ka carbon atoms, me kahi kumu hoʻohālike kūpono o B ₄ C, ʻoiai hiki ke ʻokoʻa kona haku mele maoli mai B ₄ C a i B ₁₀. ELIMA C, e hōʻike ana i kahi ʻano homogeneity nui i hoʻokele ʻia e nā ʻōnaehana ʻē aʻe i loko o kāna lattice crystal paʻakikī.
ʻO ke kiʻi aniani o ka boron carbide mai ka ʻōnaehana rhombohedral (hui lewa R3̄m), ʻike ʻia e kahi pūnaewele ʻekolu-dimensional o 12-atom icosahedra– nā hōʻiliʻili o nā ʻātoma boron– hoʻopili ʻia e nā kaulahao C-B-C a i ʻole C-C ma ke koʻi koʻikoʻi.
ʻO kēia mau icosahedra, kela a me keia i komo 11 nā ʻātoma boron a me 1 ʻātoma kalapona (B ₁₁ C), ua hoʻopaʻa ʻia me ka B ikaika loa– B, B– C, a me C– C paa, e hāʻawi ana i kona ikaika mechanical a me ka palekana wela.
ʻO ka ʻike ʻia o kēia mau ʻāpana polyhedral a me nā kaulahao interstitial e hoʻolauna i ka anisotropy architectural a me nā pilikia intrinsic., e pili ana i ka hana mechanical a me na hale kikoho'e o ka huahana.
ʻAʻole like me nā porcelains maʻalahi e like me ka alumina a i ʻole ka silika carbide, ʻO ka hoʻolālā atomika o boron carbide e hiki ai ke hoʻololi i ka hoʻonohonoho hoʻonohonoho, hiki ke hoʻokumu i nā hemahema a me ke kaʻe ʻana o ka uku e hoʻopilikia i kāna hana ma lalo o ke kaumaha a me ka hopohopo a me ka irradiation.
1.2 Nā Noho Kino a me Elele e loaʻa mai ana mai ka Atomic Bonding
ʻO ka pūnaewele hoʻopaʻa covalent i ka boron carbide e alakaʻi i kekahi o nā mea paʻakikī kiʻekiʻe loa i ʻike ʻia ma waena o nā mea synthetic.– ʻO ka lua wale nō i ka ruby a me cubic boron nitride– maʻamau mai 30 i 38 ʻO ka awelika helu helu ma ka laulā paʻa o Vickers.
Ua emi loa kona mānoanoa (~ 2.52 g/cm EONO), hana a puni 30% ʻoi aku ka māmā ma mua o ka alumina a kokoke 70% ʻoi aku ka māmā ma mua o ke kila, he pono koʻikoʻi i nā noi paona e like me ka pale a me nā ʻāpana aerospace.
Hōʻike ka Boron carbide i ka inertness kemika koʻikoʻi, ka pale ʻana i ka hahau ʻana e ka nui o nā waikawa a me nā antacids i ka pae wela o ka lewa, ʻoiai hiki iā ia ke oxidize 450 ° C i ka ea, hana ana i ka boric oxide (B ₂ O EONO) a me co2, hiki ke hoʻololi i ka ʻoiaʻiʻo o ke kūkulu ʻana i nā hoʻonohonoho oxidative kiʻekiʻe.
Loaʻa iā ia kahi pūhaka ākea (~ 2.1 eV), ka hoʻokaʻawale ʻana iā ia ma ke ʻano he semiconductor me nā mea hiki ke hoʻohana ʻia i nā uila uila kiʻekiʻe a me nā mea ʻike radiation.
Eia kekahi, ʻO kona kiʻekiʻe Seebeck coefficient a me ka hoʻohaʻahaʻa thermal conductivity e lilo ia i moho no ka hoʻololi ʻana i ka ikehu thermoelectric, ʻoi aku ma nā wahi koʻikoʻi kahi e hāʻule ai nā mea kahiko.
(ʻO Boron Carbide Ceramic)
Hōʻike pū ka huahana i ka hoʻoheheʻe ʻana o ka neutron ma muli o ke kiʻekiʻe o ka hopu neutron kiʻekiʻe o ka ¹⁰ B isotope. (pili ana 3837 hale papaa no nā neutron wela), he mea nui ia i nā koʻokoʻo mana reactor nuklea, pale ana, a hoʻokomo i nā ʻōnaehana hoʻopaʻa kinoea.
2. Hoʻohuihui, Ka lawelawe ʻana, a me nā mea pale i ka Densification
2.1 Hana Hana Hana a me ka Pauda
Hoʻokumu nui ʻia ka Boron carbide me ka hoʻemi ʻana o ka carbothermal kiʻekiʻe o ka wai boric (H ₃ BO ₃) aiʻole boron oxide (B ₂ O ELIMA) me nā kumuwaiwai kalapona e like me ka petroleum coke a i ʻole ka lanahu i nā mea hoʻomehana arc uila e holo ana 2000 ° C.
Hoʻomaka ka pane e like me: 2B ELUA O ELUA + 7C → B ʻEhā C + 6CO, hana ʻinoʻino, ʻO nā pauka angular e pono ai ka wili nui ʻana e hoʻokō i ka nui o nā ʻāpana submicron kūpono no ka lawelawe ʻana i ka keramika..
ʻO nā ala synthesis ʻē aʻe e pili ana i ka hoʻolaha pilikino kiʻekiʻe-mehana synthesis (SHS), ka hoʻoheheʻe ʻana i ka mahu kemika i hoʻokomo ʻia e ka laser (CVD), a me nā ʻenehana kōkua plasma, ʻoi aku ka maikaʻi o ka mana ma luna o ka stoichiometry a me ka morphology ʻāpana akā ʻaʻole hiki ke hoʻonui ʻia no ka hoʻohana ʻana i ka ʻoihana..
Ma muli o kona paʻa paʻa, ʻO ka wili ʻana i ka boron carbide i loko o nā pauka nui he ikaika nui ka ikehu a hiki ke hoʻopōʻino ʻia mai ka pāpaʻi paʻi., koi ana i ka hoʻohana ʻana i nā wili boron carbide-lined a i ʻole nā mea kōkua wili polymeric e mālama i ka maʻemaʻe.
Pono e ʻike pono ʻia nā pauka i loaʻa a deagglomerated i mea e hōʻoiaʻiʻo ai i ka paʻi like ʻana a me ka sintering hilinaʻi.
2.2 Nā palena Sintering a me nā ala hoʻohui kiʻekiʻe
ʻO kahi paʻakikī koʻikoʻi i ka hana ʻana o ka boron carbide ceramic ʻo kona ʻano hoʻopaʻa covalent a me ka coefficient diffusion haʻahaʻa., ka mea e kaupalena nui i ka densification i ka wā maʻamau pressureless sintering.
Eia kekahi i nā mahana e kokoke mai ana 2200 ° C, ʻO ka hoʻopaʻa ʻana ʻole ʻia e hana maʻamau i nā porcelains me 80– 90% o ka mānoanoa hoʻonaʻauao, e waiho ana i ke koena porosity e hoʻohaʻahaʻa i ka ikaika mechanical a me ka hana ballistic.
No ka lanakila ʻana i kēia, nā ʻenehana hoʻopaʻapaʻa holomua e like me ke kuʻi wela (HP) a me ka hookui isostatic wela (HIP) hoʻohana ʻia.
Hoʻohana ka hoʻokuke wela i ke koʻikoʻi uniaxial (maʻa mau 30– 50 MPa) i nā mahana ma waena 2100 ° C a 2300 ° C, ka paipai ʻana i ka hoʻonohonoho hou ʻana i nā ʻāpana a me ka deformation plastic, e ʻae ana i ka mānoanoa nui 95%.
ʻOi aku ka maikaʻi o ka HIP ma o ka hoʻohana ʻana i ke kaomi kinoea isostatic (100– 200 MPa) ma hope o ka hoʻopili ʻana, e hoʻopau ana i nā pores i pani ʻia a loaʻa i kahi kokoke piha piha me ka hoʻomaikaʻi ʻana i ka paʻakikī māwae.
Nā mea hoʻohui e like me ke kalapona, silika, a i ʻole e hoʻololi i nā pahu metala (e.g., TiB ELUA, CrB ELUA) Hoʻokomo ʻia i kekahi manawa ma kahi liʻiliʻi e hoʻonui i ka sinterability a keʻakeʻa i ka ulu ʻana o ka palaoa, ʻoiai hiki iā lākou ke hōʻemi iki i ka ikaika a i ʻole ka neutron absorption efficiency.
ʻOiai kēia mau holomua, ʻO ka nāwaliwali o ka palena o ka palaoa a me ka brittleness intrinsic ke hoʻomau nei i mau pilikia mau loa, ma lalo o nā kūlana hoʻouka ikaika.
3. Nā Hana Mechanical a me ka hana ma lalo o nā kūlana hoʻouka ʻoi loa
3.1 Nā Pūnaehana Kūʻē Ballistic a me ka ʻAʻole
Hoʻomaopopo nui ʻia ʻo Boron carbide ma ke ʻano he kumu mua no ka pale ballistic māmā i ka pale kino, kaʻa kaʻa, a me ka pale mokulele.
ʻO kona kūpaʻa kiʻekiʻe e hiki ai iā ia ke hōʻino pono a hoʻopaʻa i nā projectiles e hiki mai ana e like me nā pōkā a me nā ʻāpana., ka hoʻoheheʻe ʻana i ka mana kinetic ma o nā ʻōnaehana me ka māwae, microcracking, a me ka hoʻololi kahua kahua.
Eia naʻe, Hōʻike ka boron carbide i kahi mea i kapa ʻia “amorphization ma lalo o ka haʻalulu,” i hea, ma lalo o ka hopena kiʻekiʻe (maʻa mau > 1.8 km/s), nahaha pono ka hale kristal i ka hookamani, pae amorphous ʻaʻole hiki ke lawe i ka ukana, ka hopena i ka pōʻino hāʻule.
ʻO kēia amorphization i hoʻoikaika ʻia, ʻike ʻia ma o ka diffraction X-ray in-situ a me nā haʻawina TEM, pili ʻia i ka haki ʻana o nā ʻōnaehana icosahedral a me nā kaulahao C-B-C ma lalo o ke koʻikoʻi ʻoki loa..
ʻO nā hoʻoikaika ʻana e hoʻēmi i kēia me ka hoʻomaikaʻi ʻana i ka palaoa, ʻano hui (e.g., B EHA C-SiC), a me ka ʻili o ka ʻili i uhi ʻia me nā kila hiki ke hoʻopaneʻe i ka hoʻonui ʻia ʻana o ka haʻihaʻi a me ka ʻāpana.
3.2 Hoʻopaʻa ʻaʻahu a me nā noi ʻoihana
Ka pale aku i hala, ʻO ke kūpaʻa abrasion o ka boron carbide he mea kūpono ia no nā noi kalepa me ka ʻaʻahu koʻikoʻi, e like me nā nozzles sandblasting, ʻōlelo ʻoki ʻoki wai, a me ka wili media.
Ua ʻoi aku kona paʻa ma mua o ka tungsten carbide a me ka alumina, e alakaʻi ana i ka lōʻihi o ke ola a me ka hoʻemi ʻana i nā kumukūʻai mālama i nā lewa hana kiʻekiʻe.
ʻO nā mea i hana ʻia mai ka boron carbide hiki ke hana ma lalo o nā kahe abrasive kiʻekiʻe me ka ʻole o ka luku wikiwiki., ʻoiai pono e mālama pono i ka pale ʻana i ka haʻalulu wela a me nā koʻikoʻi tensile i ka wā o ke kaʻina hana.
ʻO kona hoʻohana ʻana i nā hoʻonohonoho nuklea e pili pū ana i nā ʻāpana pale ʻaʻahu i nā ʻōnaehana hoʻokele kinoea, kahi e pono ai ka ikaika mechanical a me ka absorption neutron.
4. Nā noi hoʻolālā ma Nukelea, Aerospace, a me nā ʻenehana hou
4.1 Neutron Absorption and Radiation Shielding Solutions
Ma waena o kekahi o nā mea koʻikoʻi koʻikoʻi no ka hoʻohana ʻole i ka pūʻali koa o ka boron carbide e noho mau ana i ka ikehu atomika, kahi e lawelawe ai ma ke ʻano he neutron-absorbing product ma nā pou mana, nā pellets pani, a me nā hale pale radiation.
Ma muli o ka waiwai nui o ka ¹⁰ B isotope (maʻamau ~ 20%, nae hiki ke hoonuiia i > 90%), Hiki ke hopu ka boron carbide i nā neutron wela ma o ka ¹⁰ B(n, a)ʻehiku Li pane, ka hana ʻana i nā ʻāpana alpha a me nā ion lithium i maʻalahi i loko o ka huahana.
ʻAʻole radioactive kēia pane a hoʻopuka i nā huahana lōʻihi loa, ʻoi aku ka palekana o ka boron carbide a ʻoi aku ka paʻa ma mua o nā mea ʻē aʻe e like me cadmium a i ʻole hafnium.
Hoʻohana ʻia ia i nā mea hoʻoulu wai kaomi (PWRs), nā mea hoʻoheheʻe wai paila (Nā BWR), a me nā mea hana noiʻi, maʻamau ma ke ʻano o nā pellet sintered, nā paipu ʻaʻahu, a i ʻole nā panela hui.
ʻO kona kūpaʻa ma lalo o ka neutron irradiation a me ka hiki ke mālama i nā huahana fission e hoʻomaikaʻi i ka palekana activator a me ka palekana a me ka hana lōʻihi..
4.2 Aerospace, Thermoelectrics, a me nā palena ʻāina e hiki mai ana
I ka aerospace, ʻIke ʻia ka boron carbide no ka hoʻohana ʻana i nā ʻaoʻao alakaʻi kaʻa hypersonic, kahi ona mea hoohehee kiekie (~ 2450 ° C), emi mānoanoa, a me ke kū'ē ha'alulu wela e hā'awi i nā mea maika'i ma mua o nā mea metala.
Loaʻa kona hiki i nā hāmeʻa thermoelectric mai kona kiʻekiʻe Seebeck coefficient a me ka hoʻohaʻahaʻa thermal conductivity, hiki i ka hoʻololi pololei ʻana i ka mehana ʻōpala i ka ikehu uila i loko o nā lewa koʻikoʻi e like me nā hoʻokolohua hohonu a i ʻole nā pūnaewele nuklea..
Ke hoʻomaka nei hoʻi ke aʻo ʻana no ka hoʻokumu ʻana i nā composites i hoʻokumu ʻia i ka boron carbide me nā nanotubes carbon a i ʻole graphene e hoʻonui ai i ka paʻakikī a me ka conductivity uila no nā mea hana uila multifunctional..
Eia kekahi, Ke hoʻohana ʻia nei kona mau hale semiconductor i nā ʻāpana ʻike paʻa i ka radiation a me nā mea ʻike no nā wahi a me nā noi nuklea..
I ka recap, ʻO nā porcelains boron carbide ke kū nei no kahi mea kumu ma ka hui ʻana o ka hana mechanical loa, hoʻolālā nukelea, a holomua ka hana.
ʻO kāna hui hoʻokahi o ke ʻano o ka paʻa kiʻekiʻe kiʻekiʻe, emi mānoanoa, a hiki i ka neutron absorption hiki ke hoʻololi i ka pale a me nā ʻenehana nuklea hou, ʻoiai ke hoʻomau nei ka noiʻi noiʻi e hoʻonui i kona ikehu i loko o ka aerospace, hoʻololi ikehu, a me nā hui o ka hanauna e hiki mai ana.
I ka hoʻonui ʻana i nā hoʻolālā hoʻomaʻemaʻe a puka mai nā hoʻolālā composite hou, E noho mau ka boron carbide ma ka poʻokela o nā mea hana hou no nā pilikia ʻenehana koi nui..
5. Mea hoolaha
ʻO Advanced Ceramics i hoʻokumu ʻia ma ʻOkakopa 17, 2012, he ʻoihana ʻenehana kiʻekiʻe i hoʻopaʻa ʻia i ka noiʻi a me ka hoʻomohala ʻana, hana ʻana, hana ʻana, kūʻai a me nā lawelawe ʻenehana o nā mea pili a me nā huahana. Loaʻa kā mākou huahana akā ʻaʻole i kaupalena ʻia i nā Boron Carbide Ceramic Products, ʻO Boron Nitride Ceramic Products, Nā Huahana Seramika Silicon Carbide, ʻO nā huahana seramika Silicon Nitride, Zirconium Dioxide Ceramic Products, etc. Inā hoihoi ʻoe, e ʻoluʻolu e hoʻokaʻaʻike mai iā mākou.([email protected])
Nā huaʻōlelo: Boron Carbide, ʻO Boron Ceramic, ʻO Boron Carbide Ceramic
ʻO nā ʻatikala a me nā kiʻi a pau mai ka Pūnaewele. Inā loaʻa kekahi pilikia kope, e ʻoluʻolu e kelepona mai iā mākou i ka manawa e holoi ai.
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