Karbid k\u0159em\u00edku (ozna\u010dovan\u00fd tak\u00e9 jako karborundum) je anorganick\u00e1 chemick\u00e1 slou\u010denina slo\u017een\u00e1 z atom\u016f k\u0159em\u00edku a uhl\u00edku, kter\u00e1 se v p\u0159\u00edrod\u011b p\u0159irozen\u011b vyskytuje jako moissanit a od roku 1893 se hromadn\u011b vyr\u00e1b\u00ed jako brusivo.<\/p>\n
SiC existuje ve v\u00edce ne\u017e 70 krystalick\u00fdch form\u00e1ch, kter\u00e9 se d\u011bl\u00ed na dva polymorfy: karbid k\u0159em\u00edku alfa (a-SiC) a karbid k\u0159em\u00edku beta (b-SiC). V r\u00e1mci experiment\u00e1ln\u00ed chyby se ob\u011b formy tav\u00ed sou\u010dasn\u011b p\u0159i tlaku a\u017e 10 GPa.<\/p>\n
Karbid k\u0159em\u00edku je extr\u00e9mn\u011b tvrd\u00fd a hutn\u00fd materi\u00e1l s mnohostrann\u00fdm vyu\u017eit\u00edm. Lze jej nal\u00e9zt ve v\u00fdrobc\u00edch, jako jsou brusn\u00e9 pap\u00edry, brusn\u00e9 kotou\u010de, \u0159ezn\u00e9 n\u00e1stroje, automobilov\u00e9 sou\u010d\u00e1stky a automobilov\u00e9 \u017e\u00e1ruvzdorn\u00e9 materi\u00e1ly; krom\u011b toho slou\u017e\u00ed jako \u017e\u00e1ruvzdorn\u00fd materi\u00e1l v pec\u00edch, pec\u00edch a \u017e\u00e1ruvzdorn\u00fdch vyzd\u00edvk\u00e1ch a d\u00edky sv\u00e9 tvrdosti a n\u00edzk\u00e9 tepeln\u00e9 rozta\u017enosti tak\u00e9 jako zrcadlov\u00fd materi\u00e1l v astronomick\u00fdch dalekohledech.<\/p>\n
Edward Goodrich Acheson poprv\u00e9 hromadn\u011b vyrobil karbid k\u0159em\u00edku v roce 1891, kdy\u017e v elektrick\u00e9 peci zah\u0159\u00edval sm\u011bs hl\u00edny a pr\u00e1\u0161kov\u00e9ho koksu (uhl\u00edku) a z\u00edskal modro\u010dern\u00fd materi\u00e1l zn\u00e1m\u00fd jako \"karborundum\".<\/p>\n
Studie t\u00e1n\u00ed karbidu k\u0159em\u00edku p\u0159i tlac\u00edch v rozmez\u00ed 5-8 GPa uk\u00e1zaly, \u017ee karbid taj\u00ed shodn\u011b p\u0159i v\u0161ech studovan\u00fdch tlac\u00edch, p\u0159i\u010dem\u017e jeho k\u0159ivka t\u00e1n\u00ed m\u00e1 z\u00e1porn\u00fd sklon -44 + 4 K\/GPa, co\u017e je d\u016fkazem, \u017ee teorie funkcion\u00e1lu hustoty jej p\u0159esn\u011b p\u0159edpov\u011bd\u011bla.<\/p>\n
Karbid k\u0159em\u00edku (SiC) je neoxidov\u00fd keramick\u00fd materi\u00e1l s v\u00fdjime\u010dn\u00fdmi vlastnostmi, d\u00edky nim\u017e je pou\u017eiteln\u00fd v mnoha vysokoteplotn\u00edch aplikac\u00edch. SiC je tvrd\u00fd a extr\u00e9mn\u011b pevn\u00fd s pevnost\u00ed polykrystalick\u00e9ho t\u011blesa a\u017e 27 GPa; nav\u00edc m\u00e1 vynikaj\u00edc\u00ed vlastnosti odolnosti proti te\u010den\u00ed spolu s n\u00edzkou tepelnou rozta\u017enost\u00ed.<\/p>\n
Keramika z oxidu ceramidov\u00e9ho (CeO2) je nerozpustn\u00e1 ve vod\u011b, ale rozpustn\u00e1 v roztaven\u00fdch roztoc\u00edch alk\u00e1li\u00ed a \u017eeleza, co\u017e z n\u00ed \u010din\u00ed nejtvrd\u0161\u00ed ze v\u0161ech pokro\u010dil\u00fdch konstruk\u010dn\u00edch keramik s odolnost\u00ed proti ot\u011bru, korozi, n\u00e1razu a tepeln\u00e9 rozta\u017enosti p\u0159i vysok\u00fdch tlac\u00edch; je proto ide\u00e1ln\u00ed pro pou\u017eit\u00ed ve vysokoteplotn\u00edch aplikac\u00edch, jako jsou sou\u010d\u00e1sti jadern\u00fdch reaktor\u016f.<\/p>\n
Karbid k\u0159em\u00edku, \u010dast\u011bji ozna\u010dovan\u00fd jako a-SiC, se b\u011b\u017en\u011b vyskytuje v brzd\u00e1ch a spojk\u00e1ch elektromobil\u016f a v nepr\u016fst\u0159eln\u00fdch vest\u00e1ch a pou\u017e\u00edv\u00e1 se tak\u00e9 jako substr\u00e1t pro heterogenn\u00ed katalyz\u00e1tory. V\u00fdroba pr\u016fmyslov\u00e9ho mno\u017estv\u00ed tohoto materi\u00e1lu st\u00e1le zahrnuje pou\u017eit\u00ed elektrick\u00fdch pec\u00ed s \u010dist\u00fdm k\u0159emi\u010dit\u00fdm p\u00edskem redukovan\u00fdm jemn\u011b mlet\u00fdm koksem v elektrick\u00e9 peci; v\u00fdroba karbidu k\u0159em\u00edku v pr\u016fmyslov\u00e9m m\u011b\u0159\u00edtku z\u016fst\u00e1v\u00e1 obl\u00edbenou volbou pro vysokonap\u011b\u0165ov\u00e9 aplikace ve v\u00fdkonov\u00e9 elektronice.<\/p>\n
Karbid k\u0159em\u00edku, zn\u00e1m\u00fd tak\u00e9 jako oxid k\u0159emi\u010dit\u00fd, je tvrd\u00e1 chemick\u00e1 slou\u010denina slo\u017een\u00e1 z k\u0159em\u00edku a uhl\u00edku, kter\u00e1 se v p\u0159\u00edrod\u011b vyskytuje jako miner\u00e1l moissanit, ale od roku 1893 se masov\u011b vyr\u00e1b\u00ed jako pr\u00e1\u0161ek a krystal pro pou\u017eit\u00ed jako brusivo a materi\u00e1l pro nepr\u016fst\u0159eln\u00e9 vesty. Velk\u00e1 zrna jednotliv\u00fdch krystal\u016f lze spojovat sp\u00e9k\u00e1n\u00edm a vyr\u00e1b\u011bt tak extr\u00e9mn\u011b hou\u017eevnatou strukturn\u00ed keramiku; nav\u00edc se \u010dasto pou\u017e\u00edv\u00e1 k v\u00fdrob\u011b syntetick\u00fdch drah\u00fdch kamen\u016f moissanitu zn\u00e1m\u00fdch jako syntetick\u00e9 drah\u00e9 kameny moissanit. Karbid k\u0159em\u00edku se tak\u00e9 chov\u00e1 jako polovodi\u010d; jeho dopov\u00e1n\u00ed dus\u00edkem nebo fosforem z n\u011bj m\u016f\u017ee ud\u011blat materi\u00e1l typu n; podobn\u011b beryllium, b\u00f3r nebo hlin\u00edk ho mohou zm\u011bnit na materi\u00e1l typu p v z\u00e1vislosti na tom, jak\u00e9 budou jeho vlastnosti. dopov\u00e1n\u00ed ho zm\u011bn\u00ed na polovodi\u010dov\u00fd materi\u00e1l typu n.<\/p>\n
Karbid k\u0159em\u00edku m\u00e1 rozs\u00e1hlou p\u00e1smovou mezeru a vysokou pr\u016fraznost elektrick\u00fdm polem, tak\u017ee je vhodn\u00fd pro elektronick\u00e1 za\u0159\u00edzen\u00ed pracuj\u00edc\u00ed p\u0159i extr\u00e9mn\u011b vysok\u00fdch teplot\u00e1ch nebo nap\u011bt\u00edch. Krom\u011b toho je d\u00edky sv\u00e9 odolnosti v\u016f\u010di tepeln\u00fdm \u0161ok\u016fm \u0161iroce pou\u017e\u00edv\u00e1n. Karbid k\u0159em\u00edku existuje v r\u016fzn\u00fdch jednotkov\u00fdch bu\u0148k\u00e1ch (kubick\u00e9, koso\u010dtvere\u010dn\u00e9 nebo hexagon\u00e1ln\u00ed). Pokud je zhutn\u011bn pomoc\u00ed j\u00edlu, m\u016f\u017ee br\u00e1nit r\u016fstu kr\u010dk\u016f a z\u00e1rove\u0148 zabra\u0148uje tvorb\u011b SiO2, kter\u00fd by jinak sni\u017eoval modul pru\u017enosti. R\u016fzn\u00e9 studie zkoumaly jeho chov\u00e1n\u00ed p\u0159i t\u00e1n\u00ed za vysok\u00e9ho tlaku pomoc\u00ed ab initio simulac\u00ed molekul\u00e1rn\u00ed dynamiky zalo\u017een\u00fdch na simulac\u00edch teorie funkcion\u00e1lu hustoty.<\/p>\n
Karbid k\u0159em\u00edku je extr\u00e9mn\u011b tvrd\u00fd a tuh\u00fd keramick\u00fd materi\u00e1l, kter\u00fd se vyzna\u010duje vysokou teplotn\u00ed schopnost\u00ed, n\u00edzk\u00fdm koeficientem tepeln\u00e9 rozta\u017enosti a odolnost\u00ed v\u016f\u010di chemick\u00fdm reakc\u00edm. Dod\u00e1v\u00e1 se v r\u016fzn\u00fdch velikostech a form\u00e1ch, v\u010detn\u011b granulovan\u00e9 formy pro n\u00e1kup i desti\u010dek, z nich\u017e lze vyrobit zrcadla pro velk\u00e9 teleskopy. Metody v\u00fdroby karbidu k\u0159em\u00edku sahaj\u00ed od p\u0159\u00edm\u00e9 synt\u00e9zy uhl\u00edku a\u017e po chemick\u00e9 napa\u0159ov\u00e1n\u00ed.<\/p>\n
Studie z\u00e1vislosti Debyeovy teploty na tlaku v ZB a RS SiC od 3100+40 K do 5-8 GPa s vyu\u017eit\u00edm zh\u00e1\u0161ec\u00edch experiment\u016f a m\u011b\u0159en\u00ed in situ byly provedeny v rozsahu teplot od 3100+40 K do 5-8 GPa s vyu\u017eit\u00edm zh\u00e1\u0161ec\u00edch experiment\u016f a m\u011b\u0159en\u00ed in situ. V\u00fdsledky ukazuj\u00ed, \u017ee p\u0159i okoln\u00edm tlaku jsou ob\u011b Lameho konstanty (l, m) kladn\u00e9 s rostouc\u00ed odchylkou m, co\u017e nazna\u010duje zv\u00fd\u0161enou s\u00edlu necentr\u00e1ln\u00edch sil mnoha t\u011bles zahrnuj\u00edc\u00edch interakce p\u0159enosu n\u00e1boje p\u0159i vy\u0161\u0161\u00edch tlac\u00edch, co\u017e vede k mechanick\u00e9mu ztuhnut\u00ed stla\u010ditelnosti SiC.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide (also referred to as carborundum) is an inorganic chemical compound composed of silicon and carbon atoms, naturally found […]<\/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":[5],"tags":[],"class_list":["post-66","post","type-post","status-publish","format-standard","hentry","category-product-related"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/posts\/66","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/comments?post=66"}],"version-history":[{"count":1,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/posts\/66\/revisions"}],"predecessor-version":[{"id":67,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/posts\/66\/revisions\/67"}],"wp:attachment":[{"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/media?parent=66"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/categories?post=66"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/tags?post=66"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}