Silicio karbidas, arba karborundas, yra kieta keramika, pirm\u0105 kart\u0105 masi\u0161kai pagaminta 1893 m. kaip abrazyvas. Nors yra nat\u016brali\u0173 pavyzd\u017ei\u0173 (moisanito brangakmeniai ir nedideli kiekiai magmin\u0117s uolienos, vadinamos korundu), dauguma \u0161iuolaikini\u0173 naudojimo b\u016bd\u0173 yra sintetiniai.<\/p>\n
SiC pasi\u017eymi dideliu atsparumu nuovargiui, dideliu \u0161ilumos laidumu ir ma\u017eu pl\u0117timosi koeficientu, tod\u0117l jis tinka gamybai, kad atlaikyt\u0173 auk\u0161t\u0105 temperat\u016br\u0105 ir i\u0161likt\u0173 tvirtas korozin\u0117je aplinkoje.<\/p>\n
Silicio karbidas yra viena i\u0161 nedaugelio med\u017eiag\u0173, pasi\u017eymin\u010di\u0173 dideliu \u0161ilumos laidumu kambario temperat\u016broje. D\u0117l savo kietumo, standumo ir temperat\u016bros stabilumo silicio karbidas yra puiki med\u017eiaga astronom\u0173 naudojamiems teleskop\u0173 veidrod\u017eiams gaminti.<\/p>\n
Teorijos tankio funkcijos teorija buvo panaudota sistemingiems teoriniams kubinio silicio karbido (3C-SiC) strukt\u016brini\u0173 parametr\u0173 ir termofizikini\u0173 savybi\u0173 galutin\u0117je temperat\u016broje tyrimams. M\u016bs\u0173 gauti rezultatai, susij\u0119 su tamprumo konstantomis ir Knoopo mikrokietumu, patenkinamai sutapo su eksperimentiniais duomenimis ir kitur paskelbtais skai\u010diavim\u0173 rezultatais.<\/p>\n
Taikydami optimizuotus strukt\u016bros modelius, taip pat gavome ZrC, TiC ir SiC defekt\u0173 susidarymo energij\u0173 atominio lygmens \u012fver\u010dius. Rezultatai atskleid\u0117, kad Debye temperat\u016bra ma\u017e\u0117ja did\u0117jant defekto atom\u0173 skai\u010diui, o CZr antisito ir VC defektai pasi\u017eymi ma\u017eesn\u0117mis susidarymo energijomis nei analogi\u0161ki VSi ir Sit defektai; j\u0173 susidarymo energijos suma\u017e\u0117jimas gali tur\u0117ti \u012ftakos 3C-SiC strukt\u016br\u0173 atsparumui viena\u0161\u0117ms ir \u0161lyties deformacijoms.<\/p>\n
Silicio karbidas yra viena kie\u010diausi\u0173 ir \u0161ilumai laid\u017eiausi\u0173 gamtoje randam\u0173 med\u017eiag\u0173, atspari r\u016bg\u0161\u010di\u0173 ir \u0161arm\u0173 poveikiui, o kar\u0161\u010diui atspari iki 1600 laipsni\u0173 C, neprarasdama tvirtumo. Be to, silicio karbidas yra puikus elektros laidininkas.<\/p>\n
D\u0117l plataus silicio karbido pralaidumo juostos tarpo jis tinka naudoti puslaidininkiniuose \u012ftaisuose, pavyzd\u017eiui, dioduose, tranzistoriuose ir tiristoriuose, o d\u0117l geb\u0117jimo atlaikyti dideles \u012ftampas ir sroves j\u012f galima naudoti ir didel\u0117s galios elektros energijos \u012ftaisuose.<\/p>\n
Akyt\u0105j\u012f SiC galima keisti pridedant grafeno nanodaleli\u0173 (GNP), taip sukuriant geresni\u0173 \u0161ilumini\u0173 savybi\u0173 turin\u010di\u0105 med\u017eiag\u0105. \u0160i\u0105 med\u017eiag\u0105 galima pagaminti sukepinant skys\u010dio faz\u0117s kibirk\u0161tine plazma stechiometrinius arba nestechiometrinius SiC miltelius; buvo i\u0161bandyti \u012fvair\u016bs sukepinimo pagalbini\u0173 med\u017eiag\u0173 (Y2O3 ir La2O3) deriniai, siekiant \u012fvertinti j\u0173 poveik\u012f akyt\u0173j\u0173 med\u017eiag\u0173 su iki 20 t\u016brio % GNP kiekiu fazinei sud\u0117\u010diai, mikrostrukt\u016brai ir \u0161iluminiam laidumui; buvo pasteb\u0117ta nemonotoni\u0161ka temperat\u016bros priklausomyb\u0117 nuo kompozit\u0173, kuriuose yra iki 20% GNP kiekio.<\/p>\n
D\u0117l unikalios silicio ir anglies atom\u0173 sud\u0117ties kristalin\u0117je gardel\u0117je SiC pasi\u017eymi ypatingomis mechanin\u0117mis savyb\u0117mis, tod\u0117l yra viena tvir\u010diausi\u0173 ir kie\u010diausi\u0173 keramini\u0173 med\u017eiag\u0173. Labai atspari r\u016bg\u0161\u010di\u0173, \u0161arm\u0173, i\u0161lydyt\u0173 drusk\u0173 korozijai ir dilimui; d\u0117l standumo ir tvirtumo SiC yra patraukli med\u017eiaga, kuri\u0105 galima naudoti ir dilimui atspariems komponentams, pavyzd\u017eiui, \u0161lifavimo diskams ar gr\u0105\u017etams mal\u016bnuose, pl\u0117stuvuose ar ekstruderiuose.<\/p>\n
Keramin\u0117 med\u017eiaga yra ne tik lengva, bet ir labai atspari terminiam sm\u016bgiui - ji gali atlaikyti iki 1600 laipsni\u0173 C temperat\u016br\u0105, neprarasdama mechanini\u0173 savybi\u0173 ir \u0161iluminio pl\u0117timosi, o ma\u017eas \u0161iluminio pl\u0117timosi greitis ir itin didelis Youngo modulis u\u017etikrina matmen\u0173 stabilum\u0105.<\/p>\n
Akytosios SiC keramikos por\u0117tumas priklauso nuo jos formavimo b\u016bdo (reakcinio sujungimo ar sukepinimo). Tyrimai parod\u0117, kad tiek elektrinis laidumas, tiek atsparumas lenkimui did\u0117ja did\u0117jant B4C kiekiui d\u0117l jo geb\u0117jimo adsorbuoti deguon\u012f i\u0161 Si-C matricos med\u017eiag\u0173 ir taip suma\u017einti fonon\u0173 sklaidos ilg\u012f.<\/p>\n
Silicio karbidas gamyboje naudojamas ir kaip abrazyvas, ir kaip pjovimo \u012frankis. D\u0117l kieto ir kar\u0161\u010diui atsparaus pavir\u0161iaus silicio karbid\u0105 taip pat galima rasti kaip elektronin\u012f puslaidinink\u012f dioduose ir tranzistoriuose, nes jo tolerancija \u012ftampai gali vir\u0161yti silicio tolerancij\u0105.<\/p>\n
Silicio karbido kietumas, atsparumas korozijai ir didelis \u0161iluminis laidumas daro j\u012f puikia med\u017eiaga apsauginei \u012frangai, pvz., \u0161almams ir \u0161arvo plok\u0161t\u0117ms, gaminti. Be to, jo cheminis inerti\u0161kumas rei\u0161kia, kad jis nereaguoja su vandeniu, tod\u0117l idealiai tinka naudoti didel\u0117s dr\u0117gm\u0117s aplinkoje, pavyzd\u017eiui, kosminiuose laivuose ir j\u016br\u0173 aplinkoje.<\/p>\n
Rekristalizuotas silicio karbidas (RSiC) pasi\u017eymi neprilygstamu mechanini\u0173, \u0161ilumini\u0173 ir elektrini\u0173 savybi\u0173 deriniu, palyginti su kitais SiC variantais. D\u0117l tankios mikrostrukt\u016bros RSiC turi ma\u017e\u0105 pl\u0117timosi koeficient\u0105, ta\u010diau i\u0161laiko stiprum\u0105 ir standum\u0105 auk\u0161toje temperat\u016broje; be to, jo tamprumo modulio vert\u0117s yra santykinai didesn\u0117s nei strukt\u016brin\u0117s cirkonio keramikos, o \u0161iluminio pl\u0117timosi koeficiento vert\u0117s, palyginti su strukt\u016brine cirkonio keramika, yra ma\u017eos.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide, or carborundum (), is a hard ceramic first mass-produced in 1893 for use as an abrasive. While natural instances exist (moissanite gems and small quantities as an igneous rock called corundum), most modern day usage occurs synthetically. SiC is known to exhibit high fatigue resistance, high thermal conductivity and a low coefficient of […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[64],"tags":[],"class_list":["post-190","post","type-post","status-publish","format-standard","hentry","category-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/posts\/190","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/comments?post=190"}],"version-history":[{"count":1,"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/posts\/190\/revisions"}],"predecessor-version":[{"id":191,"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/posts\/190\/revisions\/191"}],"wp:attachment":[{"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/media?parent=190"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/categories?post=190"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/lt\/wp-json\/wp\/v2\/tags?post=190"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}