1. Muhimmin Chemistry da Crystallographic Design na Boron Carbide
1.1 Haɗin Halitta da Ƙarfin Tsarin
(Boron Carbide Ceramic)
Boron carbide (B HUDU C) yana tsaye a matsayin ɗaya daga cikin mafi ban sha'awa da fasaha mai mahimmanci kayan yumbura saboda haɗuwa ta musamman na tsayin daka., ƙananan kauri, da kuma na musamman iya sha neutron.
Na kimiyya, abu ne wanda ba na stoichiometric ba da farko wanda ya ƙunshi boron da carbon atom, tare da ingantaccen tsari na B ₄ C, ko da yake ainihin abun da ke ciki na iya bambanta daga B ₄ C zuwa B ₀. BIYAR C, yana nuna babban nau'in lu'u-lu'u wanda ke ƙarƙashin tsarin madadin a cikin hadadden lattice ɗin sa.
Tsarin crystal na boron carbide ya fito ne daga tsarin rhombohedral (tawagar sararin samaniya R3̄m), gano ta hanyar hanyar sadarwa mai girma uku na 12-atom icosahedra– tarin zarra na boron– an haɗa ta kai tsaye C-B-C ko C-C sarƙoƙi tare da trigonal axis.
Wadannan icosahedra, kowanne ya kunshi 11 boron zarra da 1 carbon zarra (B ₁ C), An haɗa haɗin gwiwa tare da ƙarfi mai ƙarfi B– B, B– C, kuma C– C bond, yana ba da gudummawa ga ƙarfin injinsa mai ban sha'awa da tsaro na thermal.
Ganuwa na waɗannan rukunin polyhedral da sarƙoƙi na tsaka-tsaki suna gabatar da anisotropy na gine-gine da matsalolin ciki, wanda ke shafar duka halayen injina da gidajen dijital na samfurin.
Ba kamar mafi sauƙi ba kamar alumina ko silicon carbide, Boron carbide's atomic architecture yana ba da damar ingantaccen daidaitawa, yana ba da damar samuwar lahani da zazzagewar kuɗin da ke tasiri aikinta a ƙarƙashin damuwa da damuwa da sakawa.
1.2 Mazaunan Jiki da Wutar Lantarki da Ke Faruwa daga Atomic Bonding
Haɗin haɗin gwiwar haɗin gwiwa a cikin boron carbide yana haifar da ɗayan mafi girman yuwuwar ƙimar ƙimar ƙima tsakanin kayan roba.– na biyu kawai zuwa ruby da cubic boron nitride– yawanci jere daga 30 ku 38 Matsakaicin matsayi akan kewayon ƙarfi na Vickers.
An rage kauri sosai (~ 2.52 g/cm SHIDA), yin shi a kusa da shi 30% mai haske fiye da alumina kuma kusan 70% mai sauƙi fiye da karfe, muhimmiyar fa'ida a aikace-aikace masu ɗaukar nauyi kamar garkuwa ɗaya da sassan sararin samaniya.
Boron carbide yana nuna rashin kuzarin sinadarai, jurewa yajin aiki da yawan acid da antacids a matakin zafin sararin samaniya, ko da yake yana iya yin oxidize 450 ° C cikin iska, haifar da boric oxide (B₂ O SHIDA) da co2, wanda zai iya lalata tsarin gaskiya a cikin saitunan oxidative mai zafi.
Yana da faffadan bandeji (~ 2.1 eV), rarraba shi azaman semiconductor tare da yuwuwar aikace-aikace a cikin na'urori masu zafi masu zafi da na'urorin gano radiation.
Bugu da kari, high Seebeck coefficient da rage thermal conductivity ya sa ya zama ɗan takara don canjin makamashi na thermoelectric, musamman a wurare masu tsanani inda kayan gargajiya suka gaza.
(Boron Carbide Ceramic)
Samfurin ya kuma nuna sharar neutron mai ban mamaki saboda babban ɓangaren kamawar neutron na ¹⁰ B isotoppe. (game da 3837 barns don thermal neutrons), mayar da shi da muhimmanci a cikin makaman nukiliya reactor kula da sanduna, karewa, da kuma saka hannun jari tsarin sararin ajiya na iskar gas.
2. Magana, Gudanarwa, da Matsaloli a cikin Densification
2.1 Hanyoyin Samar da Masana'antu da Hanyoyin Gina Foda
Boron carbide an halicce shi da yawa tare da rage yawan zafin jiki na carbothermal na boric acid (H BO ₃) ko kuma boron oxide (B ₂ YA BIYAR) tare da albarkatun carbon kamar man fetur koke ko gawayi a cikin dumama baka na lantarki yana gudana 2000 ° C.
Amsar ta ci gaba kamar yadda: 2B BIYU YA BIYU + 7C → B HUDU C + 6CO, samar da m, foda masu kusurwa waɗanda ke buƙatar ƙwaƙƙwaran niƙa don cimma girman guntun guntun submicron wanda ya dace da sarrafa yumbu.
Madadin hanyoyin haɗin kai sun haɗa da haɓaka yanayin zafin jiki mai kai da kai (Farashin SHS), tururin sinadarai mai haifar da laser (CVD), da fasaha na taimakon plasma, waɗanda ke amfani da mafi kyawun iko akan stoichiometry da ɓangarorin ilimin halittar jiki duk da haka ba su da ƙima don amfanin masana'antu.
Saboda tsananin karfinsa, nika boron carbide daidai cikin babban foda yana da ƙarfi da ƙarfi kuma yana da rauni ga gurɓata daga kafofin watsa labarai., mai buƙatar yin amfani da injina mai layi na boron carbide ko kayan niƙa na polymeric don kiyaye tsabta.
Ya kamata a gano abubuwan da suka haifar da foda a hankali kuma a lalata su don ba da garantin tattara kaya iri ɗaya da amintaccen sintepon.
2.2 Ƙayyadaddun Ƙirar Ƙarfafawa da Ci Gaban Haɗuwar Hanyoyi
Matsala mai mahimmanci a cikin ginin yumbura na boron carbide shine yanayin haɗin kai da ƙarancin rarraba kai., wanda ke iyakance ƙarancin ƙima yayin daidaitaccen matsi mara ƙarfi.
Hakanan a yanayin zafi yana gabatowa 2200 ° C, Sintering mara ƙarfi gabaɗaya yana samar da faranti tare da 80– 90% na ilimi kauri, barin ragowar porosity wanda ke lalata ƙarfin injiniya da aikin ballistic.
Don cin nasara akan wannan, dabarun densification na ci gaba kamar turawa mai zafi (HP) da zafi isostatic turawa (HIP) ana amfani da su.
Zafin turawa ya shafi damuwa uniaxial (yawanci 30– 50 MPa) a yanayin zafi tsakanin 2100 ° C da 2300 ° C, inganta gyare-gyaren guntu da nakasar filastik, kyale kauri ya wuce gona da iri 95%.
HIP har ma yana ƙara haɓaka ɗimbin yawa ta hanyar amfani da iskar gas ɗin isostatic (100– 200 MPa) bayan encapsulation, kawar da rufaffiyar pores da samun kusa-cikakken yawa tare da ingantacciyar taurin fasa.
Additives kamar carbon, siliki, ko motsi karfe borides (misali, TiB BIYU, CrB NA BIYU) wasu lokuta ana gabatar da su a cikin ƙananan ƙima don haɓaka haɓakawa da hana haɓakar hatsi, ko da yake suna iya ɗan rage ƙarfin ƙarfi ko ingantaccen sha neutron.
Duk da wadannan nasarorin, Rauni kan iyakokin hatsi da gaɓoɓin ɓarna na ci gaba da zama ƙalubale marasa ƙarfi, musamman a ƙarƙashin yanayin ɗaukar nauyi.
3. Ayyukan Injini da Ayyuka A Ƙarƙashin Matsanancin Yanayin Loading
3.1 Tsarukan Juriya da Rashin Gaggawa
Boron carbide an san shi da yawa azaman babban abu don kariyar ballistic mara nauyi a cikin sulke na jiki, platin mota, da garkuwar jirgin.
Ƙarfin ƙarfinsa yana ba shi damar lalacewa da kyau da kuma jujjuya kayan aikin da ke shigowa kamar su harsasai masu huda sulke da guntu., watsar da motsin motsi ta hanyar tsarin da ke kunshe da fashewa, microcracking, da canjin matakin gida.
Duk da haka, boron carbide yana nuna wani abu da ake kira “amorphization karkashin girgiza,” ina, ƙarƙashin tasiri mai girma (yawanci > 1.8 km/s), tsarin crystalline yana rushewa daidai cikin rashin lafiya, amorphous lokaci wanda ba shi da damar ɗaukar nauyi, wanda ya haifar da gazawa mai ban tausayi.
Wannan amorphization na matsa lamba, ana lura da su ta wurin diffraction X-ray da kuma nazarin TEM, ana danganta shi da rushewar tsarin icosahedral da sarƙoƙi na CB-C a ƙarƙashin matsanancin damuwa mai ƙarfi..
Ƙoƙarin rage wannan ya ƙunshi inganta hatsi, salo mai hadewa (misali, B HUDU C-SiC), da farfajiyar da ke rufe da karafa masu jujjuyawa don jinkirta yaduwar karaya da samun rarrabuwa.
3.2 Saka Resistance da Aikace-aikacen Masana'antu
Tsaron da ya gabata, boron carbide's abrasion juriya ya sa ya dace don aikace-aikacen kasuwanci ciki har da lalacewa mai tsanani, irin su nozzles masu fashewa, tukwici yankan jet ruwa, da kuma niƙa kafofin watsa labarai.
Ƙarfinsa ya zarce na tungsten carbide da alumina, yana haifar da tsawaita rayuwa da kuma rage farashin kulawa a cikin manyan masana'antun masana'antu.
Abubuwan da aka yi daga boron carbide na iya aiki a ƙarƙashin matsi mai ƙarfi ba tare da lalata da sauri ba, ko da yake dole ne a buƙaci kulawa don hana tashin hankali na thermal da damuwa yayin aiki.
Amfani da shi a cikin saitunan nukiliya kuma ya kai ga abubuwan da ba su da ƙarfi a cikin tsarin sarrafa iskar gas, inda ake buƙatar ƙarfin injina da sha neutron duka.
4. Dabarun Aikace-aikace a cikin Nukiliya, Jirgin sama, da kuma Emerging Technologies
4.1 Neutron Absorption da Maganin Garkuwar Radiation
Daga cikin mahimman aikace-aikacen da ba na soja ba na boron carbide ya rage a cikin makamashin atomic, inda yake aiki azaman samfur mai ɗaukar neutron a cikin sandunan sarrafawa, ƙulli pellets, da kuma tsarin kariya na radiation.
Saboda yawan arzikin ¹⁰ B isotop (kullum ~ 20%, duk da haka ana iya wadatar da shi zuwa > 90%), boron carbide da kyau yana kama neutrons na thermal ta hanyar ¹⁰ B(n, a)bakwai Li amsa, ƙirƙirar gutsuttsura alpha da ions lithium waɗanda ke cikin sauƙin ƙunshe a cikin samfurin.
Wannan matakin ba shi da radiyo kuma yana haifar da samfuran da ba a daɗe ba, yin boron carbide ya fi aminci kuma ya fi kwanciyar hankali fiye da madadin kamar cadmium ko hafnium.
Ana yin amfani da shi a cikin masu kunna ruwa mai matsa lamba (PWRs), tafasasshen ruwa reactors (BWRs), da masu kunnawa bincike, yawanci a cikin nau'i na sintered pellets, attired tubes, ko bangarori masu hade.
Kwanciyarsa a ƙarƙashin iskar neutron da ikon kula da samfuran fission yana inganta amincin activator da tsaro da aiki tsawon rai..
4.2 Jirgin sama, Thermoelectrics, da Future Material Frontiers
A cikin sararin samaniya, Ana gano boron carbide don amfani dashi a cikin manyan ɓangarorin mota na hypersonic, inda ta high narkewa factor (~ 2450 ° C), rage kauri, da thermal shock juriya bayar da abũbuwan amfãni a kan karfe gami.
Ƙarfinsa a cikin na'urorin thermoelectric ya fito ne daga babban adadin Seebeck da kuma rage yawan zafin jiki, yana ba da damar juyar da dumin sharar kai tsaye zuwa makamashin lantarki a cikin yanayi mai tsanani kamar binciken zurfin sararin samaniya ko tsarin makamashin nukiliya..
Ana kuma ci gaba da nazari don kafa abubuwan haɗin gwiwar boron carbide tare da carbon nanotubes ko graphene don haɓaka tauri da ƙarfin lantarki don kayan aikin gine-ginen multifunctional..
Bugu da kari, Ana yin amfani da gine-ginen semiconductor a cikin raƙuman jiyya masu taurin radiation da masu gano abubuwa don yanki da aikace-aikacen nukiliya..
A sake fasalin, boron carbide porcelains sun tsaya don kayan tushe a mahaɗin matsanancin ingancin injina, makaman nukiliya, da ci gaban samarwa.
Haɗin sa ɗaya-na-a-iri na ƙarfin ƙarfi mai ƙarfi, rage kauri, da ikon sha neutron ya sa ba za a iya maye gurbinsa ba a cikin tsaro da fasahar zamani ta nukiliya, yayin da ci gaba da binciken bincike ya rage don faɗaɗa ƙarfinsa daidai cikin sararin samaniya, canjin makamashi, da mahadi masu zuwa.
Yayin da dabarun haɓaka haɓakawa da sabbin ƙira masu haɗaka ke fitowa, boron carbide tabbas zai ci gaba da kasancewa a kan gaba na ƙirƙira kayan don mafi yawan matsalolin fasaha..
5. Mai rarrabawa
Advanced Ceramics kafa a Oktoba 17, 2012, babban kamfani ne na fasaha mai himma ga bincike da haɓakawa, samarwa, sarrafawa, tallace-tallace da sabis na fasaha na yumbu dangi kayan da samfurori. Kayayyakinmu sun haɗa amma ba'a iyakance ga samfuran yumbura na Boron Carbide ba, Boron Nitride Ceramic Products, Silicon Carbide Ceramic Products, Silicon Nitride Ceramic Products, Zirconium Dioxide Ceramic Products, da dai sauransu. Idan kuna sha'awar, don Allah a ji daɗin tuntuɓar mu.([email protected])
Tags: Boron Carbide, Boron Ceramic, Boron Carbide Ceramic
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