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Fina-finan Graphite na iya kare na'urorin lantarki daga hasken lantarki (EM), amma dabarun da ake amfani da su a yanzu don kera su suna ɗaukar sa'o'i da yawa kuma suna buƙatar yanayin zafi na kusan digiri 3000 na Celsius. Wata ƙungiyar masu bincike daga Dakin gwaje-gwaje na Ƙasa na Shenyang don Kimiyyar Kayan Aiki a Kwalejin Kimiyya ta China yanzu ta nuna wata hanya ta daban ta yin fina-finan graphite masu inganci cikin 'yan daƙiƙa kaɗan ta hanyar kashe zare mai zafi na foil ɗin nickel a cikin ethanol. Yawan girma ga waɗannan fina-finan ya fi girma fiye da yadda ake amfani da su a yanzu, kuma ƙarfin wutar lantarki da ƙarfin injina na fina-finan sun yi daidai da na fina-finan da aka yi ta amfani da wurin adana tururi na sinadarai (CVD).
Duk na'urorin lantarki suna samar da wasu haskoki na EM. Yayin da na'urori ke ƙara ƙanƙanta kuma suna aiki a mitoci masu girma da girma, yuwuwar tsangwama ta hanyar lantarki (EMI) tana ƙaruwa, kuma tana iya yin mummunan tasiri ga aikin na'urar da kuma na tsarin lantarki da ke kusa.
Graphite, wani allotrope na carbon da aka gina daga yadudduka na graphene wanda ƙarfin van der Waals ya riƙe, yana da wasu halaye na lantarki, zafi da na inji masu ban mamaki waɗanda suka sa ya zama garkuwa mai tasiri ga EMI. Duk da haka, yana buƙatar kasancewa a cikin siffa mai siriri don ya sami babban ƙarfin lantarki, wanda yake da mahimmanci ga aikace-aikacen EMI masu amfani saboda yana nufin cewa kayan zai iya haskakawa da kuma sha raƙuman EM yayin da suke hulɗa da masu ɗaukar caji a cikinsa.
A halin yanzu, manyan hanyoyin yin fim ɗin graphite sun haɗa da ko dai pyrolysis mai zafi mai yawa na polymers masu ƙanshi ko kuma tara layin graphene (GO) oxide ko graphene nanosheets kowane layi. Duk hanyoyin biyu suna buƙatar yanayin zafi mai zafi na kusan 3000 °C da lokutan sarrafawa na awa ɗaya. A cikin CVD, yanayin zafi da ake buƙata yana ƙasa (tsakanin 700 zuwa 1300 °C), amma yana ɗaukar 'yan awanni don yin fim ɗin nanometer mai kauri, koda a cikin injin tsabtace iska.
Wata ƙungiya da Wencai Ren ke jagoranta yanzu ta samar da fim ɗin graphite mai inganci na tsawon nanomita goma a cikin daƙiƙa kaɗan ta hanyar dumama foil ɗin nickel zuwa 1200 °C a cikin yanayin argon sannan ta nutsar da wannan foil cikin sauri a cikin ethanol a 0 °C. Kwayoyin carbon da aka samar daga rugujewar ethanol suna yaɗuwa kuma suna narkewa cikin nickel saboda yawan narkewar carbon da ƙarfe ke da shi (0.4 wt% a 1200 °C). Saboda wannan narkewar carbon yana raguwa sosai a ƙananan zafin jiki, ƙwayoyin carbon daga baya suna rabuwa kuma suna zubewa daga saman nickel yayin kashewa, suna samar da fim ɗin graphite mai kauri. Masu binciken sun ba da rahoton cewa kyakkyawan aikin catalytic na nickel shima yana taimakawa wajen samar da graphite mai yawan kristal.
Ta hanyar amfani da haɗin na'urar hangen nesa mai ƙuduri mai girma, fasahar X-ray diffraction da kuma na'urar hangen nesa ta Raman, Ren da abokan aikinsa sun gano cewa graphite ɗin da suka samar yana da matuƙar lu'ulu'u a kan manyan wurare, an yi shi da kyau kuma ba shi da lahani a bayyane. Ƙarfin wutar lantarki na fim ɗin ya kai 2.6 x 105 S/m, kamar fina-finan da aka noma ta hanyar CVD ko dabarun zafin jiki mai yawa da kuma matse fina-finan GO/graphene.
Domin gwada yadda kayan zai iya toshe hasken EM, ƙungiyar ta canja fim ɗin da ke da faɗin faɗin 600 mm2 zuwa kan abubuwan da aka yi da polyethylene terephthalate (PET). Sannan suka auna ingancin kariyar fim ɗin EMI (SE) a cikin kewayon mitar X-band, tsakanin 8.2 da 12.4 GHz. Sun sami EMI SE fiye da 14.92 dB don fim mai kauri kusan nm 77. Wannan ƙimar ta ƙaru zuwa fiye da 20 dB (ƙaramin ƙimar da ake buƙata don aikace-aikacen kasuwanci) a cikin dukkan X-band lokacin da suka tara ƙarin fina-finai tare. Hakika, fim ɗin da ke ɗauke da guda biyar na fina-finan graphite (kimanin kauri 385 nm a jimilla) yana da EMI SE na kusan 28 dB, wanda ke nufin cewa kayan zai iya toshe 99.84% na hasken da ya faru. Gabaɗaya, ƙungiyar ta auna kariyar EMI na 481,000 dB/cm2/g a cikin X-band, wanda ya fi duk kayan da aka ruwaito a baya.
Masu binciken sun ce gwargwadon iliminsu, fim ɗin graphite ɗinsu shine mafi siriri a cikin kayan kariya da aka ruwaito, tare da aikin kariyar EMI wanda zai iya biyan buƙatun aikace-aikacen kasuwanci. Sifofin injinan sa suma suna da kyau. Ƙarfin karyewar kayan na kimanin 110 MPa (wanda aka ciro daga lanƙwasa-layin damuwa na kayan da aka sanya akan tallafin polycarbonate) ya fi na fina-finan graphite da aka haɓaka ta sauran hanyoyin. Fim ɗin yana da sassauƙa, kuma ana iya lanƙwasa shi sau 1000 tare da radius mai lanƙwasa na 5 mm ba tare da rasa halayen kariyar EMI ba. Hakanan yana da kwanciyar hankali har zuwa 550 °C. Ƙungiyar ta yi imanin cewa waɗannan da sauran kaddarorin suna nufin cewa za a iya amfani da shi azaman kayan kariyar EMI mai matuƙar siriri, mai sauƙi, mai sassauƙa kuma mai tasiri don aikace-aikace a fannoni da yawa, gami da sararin samaniya da na lantarki da na'urorin lantarki.
Karanta ci gaba mafi mahimmanci da ban sha'awa a fannin kimiyyar kayan aiki a cikin wannan sabon mujallar budewa.
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Lokacin Saƙo: Mayu-07-2020