1. Chemistry Yoyambira ndi Crystallographic Design ya Boron Carbide
1.1 Mapangidwe a Mamolekyu ndi Kuvuta Kwamapangidwe
(Boron Carbide Ceramic)
Boron carbide (B IFOUR C) Chimayima ngati chimodzi mwazinthu zochititsa chidwi komanso zofunika kwambiri paukadaulo wa ceramic chifukwa cha kuphatikiza kwake kwapadera komanso kulimba kolimba., makulidwe otsika, ndi luso lapadera la kuyamwa kwa neutroni.
Mankhwala, ndi chinthu chopanda stoichiometric chomwe chimapangidwa makamaka ndi ma atomu a boron ndi carbon, ndi njira yabwino ya B ₄ C, ngakhale mawonekedwe ake enieni amatha kusiyana kuchokera ku B ₄ C mpaka B ₁₀. ZISANU C, kuwonetsa mitundu yayikulu yamitundu yosiyanasiyana yoyendetsedwa ndi machitidwe ena mkati mwa kristalo wake wovuta.
Makristalo a boron carbide amachokera ku rhombohedral system (gulu la mlengalenga R3̄m), yodziwika ndi netiweki ya mbali zitatu ya 12-atomu icosahedra– kusonkhanitsa ma atomu a boron– olumikizidwa ndi maunyolo achindunji a C-B-C kapena C-C motsatana ndi ma axis atatu.
Izi ndizosahedra, iliyonse yopangidwa ndi 11 ma atomu a boron ndi 1 atomu ya carbon (B ₁₁ C), amagwirizana kwambiri ndi B amphamvu kwambiri– B, B– C, ndi C– C zomangira, kumathandizira ku mphamvu yake yodabwitsa yamakina ndi chitetezo chamafuta.
Kuwonekera kwa mayunitsi a polyhedral awa ndi maunyolo olumikizirana kumabweretsa zovuta zamapangidwe a anisotropy ndi zovuta zamkati., zomwe zimakhudza zizolowezi zamakina komanso nyumba zama digito zomwe zimapangidwa.
Mosiyana ndi zadothi zosavuta monga alumina kapena silicon carbide, mapangidwe a atomiki a boron carbide amalola kusinthasintha kwakukulu, kupangitsa kuti zikhale zotheka kupanga zolakwika komanso kufalikira kwa chiwongola dzanja chomwe chimakhudza magwiridwe antchito ake pansi pa nkhawa komanso nkhawa komanso kuyatsa.
1.2 Nyumba Zakuthupi ndi Zamagetsi Zochokera ku Atomic Bonding
Kulumikizana kogwirizana mu boron carbide kumatsogolera ku chimodzi mwazinthu zodziwika bwino kwambiri zolimba pakati pa zida zopangira.– yachiwiri ku ruby ndi kiyubiki boron nitride– makamaka kuyambira 30 ku 38 Avereji ya giredi pagulu lolimba la Vickers.
makulidwe ake amachepetsedwa kwambiri (~ 2.52 g/cm 6), kupanga kuzungulira 30% chopepuka kuposa aluminiyamu komanso pafupifupi 70% chopepuka kuposa chitsulo, Ubwino wofunikira pakugwiritsa ntchito zoletsa kulemera monga chishango chamunthu payekha ndi zida zakuthambo.
Boron carbide imawonetsa kusakhazikika kwamankhwala, kupirira kugunda kwa ma asidi ambiri ndi maantacid okhala ndi kutentha kwamlengalenga, ngakhale akhoza kukhala oxidize 450 ° C mumlengalenga, kupanga boric oxide (B ₂ O chisanu ndi chimodzi) ndi co2, zomwe zitha kusokoneza kukhulupirika kwamapangidwe pamapangidwe apamwamba kwambiri a oxidative.
Ili ndi bandgap yayikulu (~ 2.1 eV), ndikuyiyika ngati semiconductor yomwe ingagwiritsidwe ntchito pamagetsi otentha kwambiri komanso zowunikira ma radiation.
Komanso, kuchuluka kwake kwa Seebeck komanso kuchepa kwa matenthedwe kumapangitsa kuti ikhale yoyenera kutembenuza mphamvu ya thermoelectric, makamaka m'malo ovuta omwe zida zachikhalidwe zimalephera.
(Boron Carbide Ceramic)
Chogulitsachi chikuwonetsanso kuyamwa kwa neutroni chifukwa cha kuchuluka kwa manyutroni amtundu wa ¹⁰ B isotope. (za 3837 nkhokwe za ma neutroni otentha), kupangitsa kuti ikhale yofunikira mu ndodo zowongolera zida za nyukiliya, kuteteza, ndi makina osungira gasi osungidwa.
2. Kaphatikizidwe, Kugwira, ndi Zopinga mu Densification
2.1 Njira Zopangira Mafakitale ndi Ufa Womanga
Boron carbide imapangidwa makamaka ndi kutentha kwambiri kwa carbothermal kuchepa kwa boric acid (H ₃ BO ₃) kapena boron oxide (B ₂ O Asanu) ndi zinthu za kaboni monga petroleum coke kapena makala muzitsulo zamagetsi zamagetsi zomwe zikuyenda 2000 °C.
Yankho limapitilira ngati: 2B AWIRI O AWIRI + 7C → B ZINAYI C + 6CO, kupanga coarse, ma ufa aang'ono omwe amafunikira mphero yochuluka kuti akwaniritse kukula kwa zidutswa za submicron zoyenera kugwiritsira ntchito ceramic.
Njira zina zophatikizira zimaphatikizirapo kufalitsa kotentha kwambiri (SHS), laser-induced chemical vapor deposition (CVD), ndi njira zothandizira plasma, zomwe zimagwiritsa ntchito kuwongolera bwino kwa stoichiometry ndi fragment morphology koma ndizocheperako pakugwiritsa ntchito mafakitale.
Chifukwa cha kulimba kwake kwakukulu, Kugaya boron carbide mpaka kukhala ufa wochuluka kumangowonjezera mphamvu komanso kungathe kuipitsidwa ndi media media., kukakamiza kugwiritsa ntchito mphero zokhala ndi boron carbide kapena zida zogaya za polymeric kuti zikhale zoyera.
The chifukwa ufa ayenera kuzindikiridwa mosamala ndi deagglomerated kutsimikizira kulongedza yunifolomu ndi sintering odalirika.
2.2 Zolephera za Sintering ndi Njira Zophatikizira Zapamwamba
Chovuta chachikulu pakumanga kwa boron carbide ceramic ndi chikhalidwe chake chogwirizana komanso kutsika kwamadzimadzi., zomwe zimachepetsa kwambiri kachulukidwe panthawi ya sintering yopanda mphamvu.
Komanso pa kutentha kuyandikira 2200 °C, sintering yopanda mphamvu nthawi zambiri imapanga ma porcelains okhala ndi 80– 90% wa makulidwe a maphunziro, kusiya porosity yotsalira yomwe imawononga mphamvu zamakina ndi magwiridwe antchito a ballistic.
Kuti tigonjetse izi, njira zowonjezera zolimba monga kukankha kotentha (HP) ndi kutentha kwa isostatic kukankha (HIP) amagwiritsidwa ntchito.
Kukankhira kotentha kumagwiranso ntchito kupsinjika kwa uniaxial (nthawi zambiri 30– 50 MPa) pa kutentha pakati 2100 °C ndi 2300 °C, kulimbikitsa kusintha kwa zidutswa ndi kusinthika kwa pulasitiki, kulola makulidwe kupitirira 95%.
HIP imapangitsanso kachulukidwe kachulukidwe pogwiritsa ntchito mpweya wa isostatic (100– 200 MPa) pambuyo encapsulation, kuchotsa ma pores otsekedwa ndikukhala pafupi ndi kachulukidwe kokwanira ndi kulimba kwa mng'alu.
Zowonjezera monga carbon, silicon, kapena kusintha zitsulo zachitsulo (mwachitsanzo, TiB TWO, CrB 2) Nthawi zina zimayambitsidwa pang'ono kuti ziwonjezeke ndikulepheretsa kukula kwa mbewu, ngakhale angachepetse pang'ono kulimba kapena kuyamwa kwa neutroni.
Ngakhale zopambana izi, Kufooka kwa malire a tirigu ndi kuwonongeka kwa mkati kumapitiriza kukhala zovuta zosalekeza, makamaka pansi pazikhalidwe zotsegula bwino.
3. Zochita Zamakina ndi Magwiridwe Pansi Pakukweza Kwambiri
3.1 Ballistic Resistance ndi Kulephera Systems
Boron carbide imadziwika kwambiri ngati chinthu choyambirira chachitetezo chopepuka cha zida zankhondo., kuyika galimoto, ndi chitetezo cha ndege.
Kulimba kwake kumapangitsa kuti iwonongeke bwino ndikupotoza ma projectile omwe akubwera monga zipolopolo zoboola zida ndi zidutswa., kuwononga mphamvu ya kinetic kudzera pamakina opangidwa ndi crack, microcracking, ndi kusintha kwa siteji yakomweko.
Komabe, boron carbide imasonyeza chodabwitsa chotchedwa “amorphization pansi pa mantha,” ku, pansi pa liwiro lalikulu (kawirikawiri > 1.8 km/s), mawonekedwe a crystalline amasweka mpaka kusokonezeka, gawo la amorphous lomwe lilibe mphamvu yonyamula katundu, kuchititsa kulephera komvetsa chisoni.
Izi kukakamiza-kuchititsa amorphization, amawonedwa kudzera mu-situ X-ray diffraction ndi maphunziro a TEM, zimachitika chifukwa cha kuwonongeka kwa machitidwe a icosahedral ndi unyolo wa C-B-C pansi pa kupsinjika kwakukulu kwa kukameta ubweya..
Zoyesayesa zochepetsera izi zimaphatikizapo kuwongolera kwambewu, kalembedwe kophatikiza (mwachitsanzo, B ZINAYI C-SiC), ndi kuphimba pamwamba ndi zitsulo pliable kuti achedwe kufalikira kwa fracture ndi kugawanika.
3.2 Wear Resistance and Industrial Applications
Chitetezo cham'mbuyo, kukana kwa abrasion ya boron carbide kumapangitsa kuti ikhale yabwino kwa ntchito zamalonda kuphatikiza kuvala kwambiri, monga ma nozzles sandblasting, nsonga zodula ndege zamadzi, ndi media media.
Kulimba kwake kumaposa tungsten carbide ndi alumina, kupangitsa kuti moyo ukhale wautali komanso kuchepetsa ndalama zolipirira m'malo opangira zinthu zambiri.
Zinthu zopangidwa kuchokera ku boron carbide zimatha kugwira ntchito movutikira kwambiri popanda kuwononga mwachangu, ngakhale kusamala kuyenera kufunidwa kuti mupewe kugwedezeka kwamafuta ndi kupsinjika kwakanthawi panthawi yakuchita.
Kugwiritsidwa ntchito kwake pamakina a nyukiliya kumafikanso pazigawo zosagwirizana ndi gasi, pomwe kulimba kwamakina ndi kuyamwa kwa neutroni ndikofunikira.
4. Strategic Applications mu Nuclear, Zamlengalenga, ndi Emerging Technologies
4.1 Neutron Absorption ndi Radiation Shielding Solutions
Chimodzi mwazinthu zofunika kwambiri zomwe si zankhondo za boron carbide zimakhalabe mu mphamvu ya atomiki, komwe imagwira ntchito ngati chinthu chotengera nyutroni mumitengo yowongolera, kutseka ma pellets, ndi zida zoteteza ma radiation.
Chifukwa cha kuchuluka kwa isotope ¹⁰ B (bwino ~ 20%, komabe akhoza kulemeretsedwa ku > 90%), boron carbide imagwira bwino ma neutroni otenthetsera kudzera pa ¹⁰ B(n, a)zisanu ndi ziwiri Li kuyankha, kupanga zidutswa za alpha ndi ma ion a lithiamu omwe amapezeka mosavuta mkati mwa mankhwalawa.
Izi ndizopanda ma radiation ndipo zimapanga zinthu zochepa zomwe zimakhala ndi moyo wautali, kupanga boron carbide kukhala yotetezeka komanso yokhazikika kuposa njira zina monga cadmium kapena hafnium.
Amagwiritsidwa ntchito m'ma activator amadzi opanikizika (Zithunzi za PWR), zopangira madzi otentha (Zithunzi za BWR), ndi oyambitsa kafukufuku, kawirikawiri mu mawonekedwe a sintered pellets, machubu ovala, kapena mapanelo kompositi.
Kukhazikika kwake pansi pa kuyatsa kwa neutron komanso kuthekera kosunga zinthu za fission kumapangitsa chitetezo ndi chitetezo cha activator komanso moyo wautali wogwira ntchito..
4.2 Zamlengalenga, Thermoelectrics, ndi Future Material Frontiers
Muzamlengalenga, boron carbide ikupezeka kuti igwiritsidwe ntchito m'mbali zotsogola zamagalimoto a hypersonic, komwe kusungunuka kwake kwakukulu (~ 2450 °C), kuchepetsedwa makulidwe, ndi kukana kutentha kwa kutentha kumapereka ubwino pazitsulo zazitsulo.
Kuthekera kwake m'zida zamagetsi zamagetsi kumachokera ku mphamvu yake yayikulu ya Seebeck ndikuchepetsa kutsika kwamafuta., kupangitsa kusintha kwachindunji kwa kutentha kwa zinyalala kukhala mphamvu yamagetsi m'malo ovuta kwambiri monga ma probe ozama kwambiri kapena zida zamagetsi zamagetsi.
Kuphunziranso kukuchitika kuti akhazikitse zida za boron carbide zokhala ndi ma carbon nanotubes kapena graphene kuti apititse patsogolo kulimba komanso kuwongolera kwamagetsi pazamagetsi zamagetsi zamagetsi zamagetsi..
Komanso, Nyumba zake za semiconductor zikuyendetsedwa ndi ma radiation-hardened sensing units ndi zowunikira zomwe zimagwiritsidwa ntchito mdera ndi zida za nyukiliya..
Mukubwereza, boron carbide porcelains amayimira maziko pamphambano yamakina kwambiri, kapangidwe ka nyukiliya, ndi kupanga patsogolo.
Kusakanikirana kwake kwamtundu umodzi wa kulimba kwambiri, kuchepetsedwa makulidwe, ndi kuthekera kwa mayamwidwe a nyutroni kumapangitsa kuti zisalowe m'malo muchitetezo komanso matekinoloje amakono anyukiliya, pamene kufufuza kosalekeza kumapitirizabe kukulitsa mphamvu zake mpaka muzamlengalenga, kutembenuka kwa mphamvu, ndi zosakaniza za m'badwo wotsatira.
Pamene njira zoyenga zikuchulukirachulukira ndipo mapangidwe atsopano amawonekera, boron carbide idzakhalabe patsogolo pazatsopano zazinthu zopinga zaukadaulo zomwe zimafunikira kwambiri..
5. Wofalitsa
Advanced Ceramics idakhazikitsidwa pa Okutobala 17, 2012, ndi bizinesi yapamwamba yodzipereka ku kafukufuku ndi chitukuko, kupanga, kukonza, malonda ndi ntchito zaukadaulo za zida za ceramic ndi zinthu. Zogulitsa zathu zikuphatikiza, koma osati zokha za Boron Carbide Ceramic Products, Boron Nitride Ceramic Products, Silicon Carbide Ceramic Products, Silicon Nitride Ceramic Products, Zirconium Dioxide Ceramic Products, ndi zina. Ngati muli ndi chidwi, chonde omasuka kulankhula nafe.([email protected])
Tags: Boron Carbide, Boron Ceramic, Boron Carbide Ceramic
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