1. Chemistry bụ isi na Crystallographic Design nke Boron Carbide
1.1 Ngwakọta molekụla na mgbagwoju anya Ọdịdị
(Ceramic boron Carbide)
boron carbide (B anọ C) na-eguzo dị ka otu n'ime ihe ndị na-adọrọ mmasị na nkà na ụzụ dị mkpa seramiiki n'ihi nchikota ya pụrụ iche nke nkwụsi ike siri ike., obere ọkpụrụkpụ, na ike absorption neutron pụrụiche.
Kemịkalụ, ọ bụ ihe na-abụghị stoichiometric nke bụ isi nke boron na carbon carbon mebere, na usoro nke ọma nke B ₄ C, ọ bụ ezie na ihe mejupụtara ya n'ezie nwere ike ịdị iche site na B ₄ C ruo B ₀. Ise C, na-egosipụta nnukwu homogeneity dị iche iche nke usoro ndị ọzọ na-achị n'ime lattice kristal dị mgbagwoju anya.
Usoro kristal nke boron carbide sitere na sistemụ rhombohedral (otu oghere R3̄m), mara site na netwọk akụkụ atọ nke 12-atom icosahedra– nchịkọta nke boron atọm– jikọtara ya na agbụ C-B-C ma ọ bụ C-C n'akụkụ axis trigonal.
Icosahedra ndị a, nke ọ bụla mejupụtara 11 boron atọm na 1 carbon atọm (B₁ C), A na-ejikọta ọnụ na nnukwu ike B– B, B– C, na C– C nkekọ, na-enye aka n'ike n'ibu ya na nchekwa okpomọkụ.
Ọhụụ nke ngalaba polyhedral ndị a na agbụ interstitial na-ewebata anisotropy ụkpụrụ ụlọ na nsogbu dị n'ime., nke na-emetụta ma usoro igwe na ụlọ dijitalụ nke ngwaahịa ahụ.
N'adịghị ka poselin dị mfe dị ka alumina ma ọ bụ silicon carbide, Ihe owuwu atomic nke boron carbide na-enye ohere maka mgbanwe nhazi dị ukwuu, na-eme ka o kwe omume ịmepụta ntụpọ na mgbasa ozi ego nke na-emetụta arụmọrụ ya n'okpuru nrụgide na nchekasị na irradiation.
1.2 Ebe obibi anụ ahụ na eletrọnịkị na-eme site na njikọta Atọmk
Netwọk njikọkọ covalent na boron carbide na-eduga n'otu n'ime uru siri ike amata nke ọma n'etiti ihe sịntetik.– nke abụọ naanị ruby na cubic boron nitride– na-emekarị sitere na 30 ka 38 Nkezi akara ọkwa na oke nkwụsi ike Vickers.
Ọkpụrụkpụ ya na-ebelata nke ukwuu (~ 2.52 g/cm isii), na-eme ya gburugburu 30% dị ọkụ karịa alumina na ọ fọrọ nke nta ka ọ bụrụ 70% Mkpa ọkụ karịa ígwè, uru dị oke mkpa na ngwa nwere mmetụta dị arọ dị ka ọta onye ọ bụla na akụkụ ikuku.
Boron carbide na-egosipụta kemịkalụ kemịkalụ pụtara ìhè, iguzogide ikuru nke otutu acid na antacids n'ogo okpomoku oghere, ọ bụ ezie na ọ nwere ike oxidize n'elu 450 Celsius C na ikuku, eke boric oxide (B ₂ O isii) na co2, nke nwere ike imebi eziokwu n'usoro na ntọala oxidative dị elu.
O nwere bandgap sara mbara (~ 2.1 eV), na-ekewa ya dị ka semiconductor nwere ngwa nwere ike na ngwa eletrọnịkị dị elu na ihe nchọpụta radieshon.
Ọzọkwa, ọnụ ọgụgụ Seebeck dị elu yana mbelata conductivity thermal na-eme ka ọ bụrụ onye ndoro-ndoro maka ngbanwe ike ọkụ ọkụ, karịsịa n'ebe ndị siri ike ebe ihe ọdịnala na-ada ada.
(Ceramic boron Carbide)
Ngwaahịa a na-egosikwa nnabata neutron dị egwu n'ihi nnukwu neutron weghara akụkụ obe nke ¹⁰ B isotope. (gbasara 3837 barns maka thermal neutrons), na-eme ka ọ dị mkpa n'ime mkpanaka njikwa ngwa agha nuklia, ichebe, na nyekwara gas nchekwa ohere usoro.
2. Synthesis, Ijikwa, na ihe mgbochi na Densification
2.1 Ụzọ mmepụta mmepụta na ntụ ntụ ntụ
A na-emepụta boron carbide n'ụzọ dị ukwuu site na mbelata carbothermal dị elu nke boric acid (H ₃ BO₃) ma ọ bụ boron oxide (B ₂ O Ise) na akụrụngwa carbon dị ka mmanụ ala coke ma ọ bụ unyi na ọkụ ọkụ arc eletrik na-agafe 2000 Celsius C.
Azịza ya na-aga n'ihu dị ka: 2B ABỤỌ O ABỤỌ + 7C → B anọ C + 6CO, na-emepụta keadighi rarii, ntụ ntụ n'akuku nke chọrọ nnukwu igwe igwe iji rụzuo nha nke mpempe submicron dabara adaba maka njikwa seramiiki..
Ụzọ njikọ ọzọ gụnyere njikọ okpomọkụ dị elu na-agbasa onwe ya (SHS), kemịkalụ vapor na-ebute laser (CVD), na usoro na-enyere aka na plasma, nke na-eji njikwa ka mma karịa stoichiometry na morphology iberibe ma enwechaghị ike maka ojiji ụlọ ọrụ.
N'ihi ike siri ike ya, igwe boron carbide ozugbo n'ime nnukwu ntụ ntụ na-enye ume ike yana adịghị ike na mmetọ sitere na mgbasa ozi grating., na-achọ iji igwe ihe igwe boron carbide ma ọ bụ ihe eji egwe ihe polymeric iji nọgide na-adị ọcha.
Ekwesịrị iji nlezianya chọpụta ntụ ntụ ndị a na-esi na ya pụta na deagglomere iji mee ka nkwakọ ngwaahịa otu na nke a pụrụ ịdabere na ya.
2.2 Mgbochi mmechi yana ụzọ njikọta dị elu
Ihe isi ike dị ukwuu na ihe owuwu seramiiki boron carbide bụ njikọ njikọ ya na obere mgbasa ozi onwe ya., nke na-amachi oke densification n'oge sintering enweghị nrụgide.
Nakwa na okpomọkụ na-abịa 2200 Celsius C, Sintering na-enweghị nrụgide na-emepụtakarị poselin nwere 80– 90% nke agụmakwụkwọ ọkpụrụkpụ, na-ahapụ porosity fọdụrụnụ nke na-eweda ume n'ibu na ịrụ ọrụ ballistic.
Iji merie nke a, usoro densification na-aga n'ihu dị ka ịkwanye ọkụ (HP) na-ekpo ọkụ isostatic pushing (HIP) na-eji.
Ịkwanye ọkụ na-emetụta nchekasị uniaxial (na-emekarị 30– 50 MPa) na okpomọkụ dị n'etiti 2100 Celsius C na 2300 Celsius C, na-akwalite nhazigharị iberibe na nrụrụ plastik, ikwe ka ọkpụrụkpụ gafere 95%.
HIP ọbụna na-eme ka densification dịkwuo mma site n'itinye nrụgide gas isostatic (100– 200 MPa) mgbe encapsulation, na-ewepu pores mechiri emechi yana nweta njupụta nso zuru oke site na iji ike mgbape ka mma.
Ihe mgbakwunye dị ka carbon, silicon, ma ọ bụ shift metal borides (eg, TiB abụọ, CrB abụọ) mgbe ụfọdụ, a na-ewebata na obere ego iji kwalite sinterability na igbochi uto ọka, ọ bụ ezie na ha nwere ike belata ntakịrị ike ike ma ọ bụ neutron absorption arụmọrụ.
N'agbanyeghị ọganihu ndị a, adịghị ike oke oke ọka na nhịkọ dị n'ime na-aga n'ihu na-abụ ihe ịma aka na-adịghị agwụ agwụ, kpọmkwem n'okpuru ọnọdụ loading dị egwu.
3. Omume arụrụ arụ na arụrụ arụ n'okpuru ọnọdụ nbudata oke
3.1 Sistemụ Nguzogide Ballistic na ọdịda
A na-amatakarị boron carbide dị ka ihe izizi maka nchekwa ballistic dị fechaa na ngwa agha ahụ, mkpuchi ụgbọ ala, na mkpuchi ụgbọ elu.
Nkwụsi ike ya dị elu na-enyere ya aka ịka njọ nke ọma na ịgbagha ngwa ọrụ na-abata dị ka mgbọ na iberibe ihe agha na-apu., na-agbasa ike kinetic site na sistemụ nwere mgbape, microcracking, na mgbanwe ogbo mpaghara.
Ka o sina dị, boron carbide na-egosiputa ihe a na-akpọ “amorphization n'okpuru ujo,” ebee, n'okpuru mmetụta ọsọ ọsọ (na-emekarị > 1.8 km/s), Ọdịdị kristal na-akụda ozugbo n'ime ọgba aghara, akụkụ amorphous nke na-enweghị ike ibu ibu, na-ebute ọdịda dị egwu.
Nke a na-akpata amorphization, hụrụ site n'ime ọnọdụ X-ray diffraction na ọmụmụ TEM, E sitere na nbibi nke sistemu icosahedral na agbụ CBC n'okpuru oke nrụgide siri ike..
Mgbalị ibelata nke a bụ mmụba ọka, ụdị agwakọta (eg, B anọ C-SiC), na ebe dị elu na-ekpuchi nchara na-atụgharị ka ọ gbuo oge mgbaji gbasaa ma nwee nkewa.
3.2 Yiri Nguzogide na Ngwa nrụpụta
Nchekwa gara aga, Mgbochi abrasion boron carbide na-eme ka ọ dị mma maka ngwa azụmahịa gụnyere oke iyi, dị ka ájá na-agbapụta nozzles, Atụmatụ igbutu ụgbọ elu mmiri, na egweri media.
Isi ike ya karịrị nke tungsten carbide na alumina, na-eduga n'ogologo ndụ ogologo yana mbelata ọnụ ahịa nchekwa n'ime ikuku nrụpụta dị elu.
Ihe ndị sitere na boron carbide nwere ike ịrụ ọrụ n'okpuru mmiri na-ekpo ọkụ dị elu na-enweghị mbibi ngwa ngwa, ọ bụ ezie na a ghaghị ịkpachara anya iji gbochie ujo okpomọkụ na nrụgide nkwụsị n'oge usoro.
Ojiji ya na ntọala nuklia na-erukwa ihe ndị na-adịghị eyi uwe na sistemụ njikwa gas, ebe ike igwe na nnabata neutron chọrọ ha abụọ.
4. Ngwa Strategic na Nuclear, Igwe ikuku, na Emerging Teknụzụ
4.1 Ntinye Neutron na Ngwọta Ọta Radiation
Otu n'ime ihe kacha mkpa na-abụghị ndị agha ngwa nke boron carbide na-anọgide na atomiki ume, ebe ọ na-eje ozi dị ka ngwaahịa na-amịpụta neutron na ogwe njikwa, mmechi pellets, na ihe owuwu mkpuchi radieshon.
N'ihi nnukwu akụ na ụba nke ¹⁰ B isotop (na-emekarị ~ 20%, Otú ọ dị, enwere ike ịba ụba na > 90%), boron carbide na-ejide neutrons thermal nke ọma site na ¹⁰ B(n, a)asaa Li nzaghachi, imepụta iberibe alfa na ion lithium nke dị mfe n'ime ngwaahịa a.
Mmeghachi omume a anaghị arụ ọrụ redio ma na-emepụta ihe ndị na-emepụta ihe na-adịru ogologo oge, na-eme ka boron carbide dị nchebe ma kwụsie ike karịa ihe ndị ọzọ dị ka cadmium ma ọ bụ hafnium.
A na-eji ya eme ihe na ndị na-arụ ọrụ mmiri (Ndị PWR), esi mmiri reactors (BWRs), na ndị na-eme nchọpụta, na-adịkarị n'ụdị pellets siri ike, attired tubes, ma ọ bụ ogwe ndị mejupụtara.
Nkwụsi ike ya n'okpuru neutron irradiation na ike idowe ngwaahịa fission na-eme ka nchekwa na nchekwa activator na ọrụ ogologo ndụ..
4.2 Igwe ikuku, Igwe ọkụ ọkụ, na Ọdịnihu Ihe Ọdịnihu
Na mbara igwe, A na-achọpụta boron carbide maka ojiji n'akụkụ ụzọ ụgbọ ala hypersonic, ebe ya elu agbaze ihe (~ 2450 Celsius C), belata ọkpụrụkpụ, na thermal ujo eguzogide na-enye uru karịa metal alloys.
Ike ya na ngwa thermoelectric sitere na ọnụọgụ Seebeck dị elu yana mbelata conductivity thermal, na-enye ohere ntụgharị ozugbo nke ikpofu ọkụ ka ọ bụrụ ike eletrik n'ime ikuku siri ike dị ka nyocha miri emi ma ọ bụ sistemu ike nuklia..
A na-agakwa ọmụmụ ihe iji guzobe ihe mejupụtara boron carbide nwere carbon nanotubes ma ọ bụ graphene iji kwalite ike na ọkụ eletrik maka ngwa eletrọnịkị ụkpụrụ ụlọ multifunctional..
Ọzọkwa, A na-etinye ụlọ semiconductor ya n'ime ngalaba mmetụta radieshon siri ike na ihe nchọpụta maka mpaghara na ngwa nuklia..
Na nchịkọta, boron carbide porcelains na-eguzo maka ihe ntọala na nkwụsị nke oke nrụpụta ọrụ, nuklia imewe, na mmepụta ihe na-aga n'ihu.
Ngwakọta nke siri ike nke ultra-high bụ otu ụdị ya, belata ọkpụrụkpụ, na ikike nnabata neutron na-eme ka ọ bụrụ ihe a na-apụghị dochie anya na nchekwa na teknụzụ ọgbara ọhụrụ nuklia, ebe ọmụmụ nyocha na-aga n'ihu na-anọgide na-agbasawanye ike ya n'ime ikuku ikuku, ntughari ike, na ogige ndị na-esote ọgbọ.
Ka usoro nnụcha na-ebuli elu yana atụmatụ ihe mejupụtara ọhụrụ na-apụta, boron carbide ga-anọgide na nsọtụ isi nke ihe ọhụrụ maka ihe mgbochi teknụzụ na-achọkarị..
5. Onye nkesa
Advanced Ceramics tọrọ ntọala na October 17, 2012, bụ ụlọ ọrụ teknụzụ dị elu kwadoro nyocha na mmepe, mmepụta, nhazi, ahịa na ọrụ aka nke seramiiki ikwu ihe na ngwaahịa. Ngwaahịa anyị gụnyere mana ọnweghị oke na ngwaahịa seramiiki Boron Carbide, Ngwaahịa seramiiki boron nitride, Ngwaahịa seramiiki Silicon Carbide, Ngwaahịa seramiiki silicon Nitride, Ngwaahịa seramiiki Zirconium Dioxide, wdg. Ọ bụrụ na ị nwere mmasị, biko nweere onwe gị ịkpọtụrụ anyị.([email protected])
Tags: Ọkpụkpụ boron carbide, Ceramic boron, Ceramic boron Carbide
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