Karbid krem\u00edka (SiC) je mimoriadne tvrd\u00e1 syntetick\u00e1 zl\u00fa\u010denina krem\u00edka a uhl\u00edka, ktor\u00e1 sa v pr\u00edrode vyskytuje ako drahokam moissanit a v men\u0161ej miere v uhl\u00edkat\u00fdch chondritov\u00fdch meteoritoch.<\/p>\n
Kreme\u0148, ktor\u00fd sa vyr\u00e1ba taven\u00edm kremi\u010dit\u00e9ho piesku a koksu pri vysok\u00fdch teplot\u00e1ch v elektrickej peci, existuje v najmenej 70 r\u00f4znych kry\u0161t\u00e1lov\u00fdch form\u00e1ch; najroz\u0161\u00edrenej\u0161ia je alfa forma s hexagon\u00e1lnou kry\u0161t\u00e1lovou \u0161trukt\u00farou podobnou wurtzitu.<\/p>\n
Karbid krem\u00edka, \u010dastej\u0161ie ozna\u010dovan\u00fd ako karborundum, je neoxidov\u00e1 keramick\u00e1 zl\u00fa\u010denina s v\u00fdnimo\u010dnou tvrdos\u0165ou a chemickou odolnos\u0165ou, ktor\u00e1 sa rad\u00ed na druh\u00e9 miesto po diamante. Okrem toho karbid krem\u00edka v \u010distej forme odol\u00e1va oxid\u00e1cii pri vy\u0161\u0161\u00edch teplot\u00e1ch pre spo\u013eahlivej\u0161iu elektrick\u00fa vodivos\u0165 a vodivos\u0165.<\/p>\n
Zahrievajte kremi\u010dit\u00fd piesok s uhl\u00edkom v elektrickej peci na v\u00fdrobu SiC. Vzniknut\u00fd zelen\u00fd a\u017e modro\u010dierny kry\u0161talick\u00fd materi\u00e1l mo\u017eno potom rozdeli\u0165 na triedy s r\u00f4znymi fyzik\u00e1lnymi vlastnos\u0165ami: napr\u00edklad metalurgick\u00e1 trieda A m\u00e1 hrub\u00e9 vrstvy, zatia\u013e \u010do hlad\u0161ie kry\u0161t\u00e1ly triedy b vytv\u00e1raj\u00fa hlad\u0161ie \u0161trukt\u00fary.<\/p>\n
Tieto polytypy vrstevnat\u00fdch \u0161trukt\u00far vykazuj\u00fa charakteristick\u00e9 elektrick\u00e9, optick\u00e9 a tepeln\u00e9 vlastnosti. Ich at\u00f3mov\u00e9 v\u00e4zby pozost\u00e1vaj\u00fa zo \u0161tyroch at\u00f3mov krem\u00edka viazan\u00fdch so \u0161tyrmi at\u00f3mami uhl\u00edka v nepravidelnom \u0161tvorcovom usporiadan\u00ed vytv\u00e1raj\u00facom \u0161tyri hexagon\u00e1lne kry\u0161t\u00e1ly; to zabezpe\u010duje vlastnosti polovodi\u010dov so \u0161irokou p\u00e1smovou medzerou. Vytl\u00e1\u010dan\u00edm alebo izostatick\u00fdm lisovan\u00edm za studena mo\u017eno tieto materi\u00e1ly tvarova\u0165 do ty\u010d\u00ed alebo r\u00farok na pou\u017eitie ako ty\u010dinky a trubice.<\/p>\n
Karbid krem\u00edka (SiC), \u010dastej\u0161ie ozna\u010dovan\u00fd ako karborundum, je tvrd\u00e1 chemick\u00e1 zl\u00fa\u010denina krem\u00edka a uhl\u00edka so \u0161irokou p\u00e1smovou medzerou a polovodi\u010dov\u00fdmi vlastnos\u0165ami. \u017diaruvzdorn\u00fd v pr\u00edrode, SiC je tie\u017e zn\u00e1my svojou vysokou tepelnou vodivos\u0165ou a n\u00edzkou tepelnou roz\u0165a\u017enos\u0165ou, v\u010faka ktorej je ve\u013emi odoln\u00fd vo\u010di tepeln\u00fdm \u0161okom.<\/p>\n
Kry\u0161talick\u00fd SiC kry\u0161talizuje v tesnej \u0161trukt\u00fare so \u0161tyrmi at\u00f3mami krem\u00edka a \u0161tyrmi at\u00f3mami uhl\u00edka viazan\u00fdmi v tetraedrickej koordin\u00e1cii a m\u00e1 viac ako 70 polytypov; alfa SiC sa naj\u010dastej\u0161ie vyskytuje pri teplot\u00e1ch nad 2000 stup\u0148ov Celzia s hexagon\u00e1lnou kry\u0161t\u00e1lovou \u0161trukt\u00farou podobnou wurtzitu. Medzit\u00fdm sa pri ni\u017e\u0161\u00edch teplot\u00e1ch vyskytuje beta modifik\u00e1cia s kry\u0161t\u00e1lovou \u0161trukt\u00farou zinkblendu podobnou diamantu a tvorba sfaleritu.<\/p>\n
Karborundum je v pr\u00edrode mimoriadne vz\u00e1cna l\u00e1tka, ale vo vesm\u00edre je z\u00e1kladn\u00fdm prvkom meteoritov bohat\u00fdch na uhl\u00edk. Tento materi\u00e1l, ktor\u00fd prv\u00fdkr\u00e1t umelo syntetizoval Edward Acheson v roku 1891 v r\u00e1mci svojej pr\u00e1ce na v\u00fdrobe umel\u00fdch diamantov, bol nakoniec v roku 1893 prirodzene objaven\u00fd v arizonskom meteorite Canyon Diablo a pomenovan\u00fd moissanit pod\u013ea nosite\u013ea Nobelovej ceny Henriho Moissana.<\/p>\n
Karbid krem\u00edka m\u00e1 extr\u00e9mne tvrd\u00fd povrch s hodnotou 9 na Mohsovej stupnici, \u010do z neho rob\u00ed najtvrd\u0161iu neoxidov\u00fa keramiku a jeden z najtvrd\u0161\u00edch materi\u00e1lov v\u00f4bec. Je vynikaj\u00facou vo\u013ebou materi\u00e1lu pre aplik\u00e1cie zah\u0155\u0148aj\u00face mechanick\u00e9 opotrebovanie, ako s\u00fa abraz\u00edva a \u017eiaruvzdorn\u00e9 materi\u00e1ly, pri\u010dom sa m\u00f4\u017ee pochv\u00e1li\u0165 dobr\u00fdmi tepeln\u00fdmi vlastnos\u0165ami, ktor\u00e9 odol\u00e1vaj\u00fa prostrediu s vysokou teplotou, ako aj tepeln\u00fdm \u0161okom.<\/p>\n
Polovicu at\u00f3mov uhl\u00edka nahr\u00e1dza krem\u00edk, ktor\u00fd v\u010faka podobn\u00e9mu at\u00f3mov\u00e9mu polomeru krem\u00edka a uhl\u00edka zabezpe\u010duje lep\u0161ie vlastnosti vedenia tepla, \u010do pom\u00e1ha zni\u017eova\u0165 rozptyl fon\u00f3nov.<\/p>\n
Karbid krem\u00edka sa vyskytuje vo forme \u017elt\u00fdch a\u017e zelen\u00fdch a\u017e modro\u010diernych d\u00fahov\u00fdch kry\u0161t\u00e1lov, ktor\u00e9 sa rozkladom pri teplote 2700 stup\u0148ov C zu\u0161\u013each\u0165uj\u00fa. Hoci je SiC nerozpustn\u00fd vo vode, je rozpustn\u00fd v roztaven\u00fdch alk\u00e1li\u00e1ch, ako s\u00fa NaOH a KOH, ako aj v roztavenom \u017eeleze a jeho Youngov modul a tvrdos\u0165 z\u00e1visia od \u0161trukt\u00fary, por\u00fach usporiadania, ve\u013ekosti z\u0155n a charakteru hran\u00edc z\u0155n.<\/p>\n
\u0160irok\u00fd energetick\u00fd p\u00e1s karbidu krem\u00edka mu umo\u017e\u0148uje odol\u00e1va\u0165 vy\u0161\u0161\u00edm teplot\u00e1m a nap\u00e4tiam ako krem\u00edk, v\u010faka \u010domu je vhodn\u00fd pre aplik\u00e1cie vy\u017eaduj\u00face r\u00fdchle a z\u00e1rove\u0148 spo\u013eahliv\u00e9 elektronick\u00e9 zariadenia. Okrem toho je jeho schopnos\u0165 odol\u00e1va\u0165 tak\u00fdmto nap\u00e4tiam neocenite\u013en\u00e1 v bat\u00e9riov\u00fdch syst\u00e9moch elektrick\u00fdch vozidiel, ktor\u00e9 zni\u017euj\u00fa ve\u013ekos\u0165 aj hmotnos\u0165 t\u00fdm, \u017ee \u00faplne eliminuj\u00fa meni\u010de.<\/p>\n
SiC je popul\u00e1rny materi\u00e1l v\u010faka kombin\u00e1cii keramick\u00fdch a polovodi\u010dov\u00fdch vlastnost\u00ed, ktor\u00e9 prispievaj\u00fa k rozvoju elektronick\u00fdch technol\u00f3gi\u00ed. Okrem toho jeho tvrdos\u0165, pevnos\u0165, n\u00edzka tepeln\u00e1 roz\u0165a\u017enos\u0165 a odolnos\u0165 vo\u010di chemick\u00fdm reakci\u00e1m prispeli k n\u00e1rastu jeho popularity.<\/p>\n
Karbid krem\u00edka sa vyr\u00e1ba zahrievan\u00edm \u010dist\u00e9ho kremi\u010dit\u00e9ho piesku s uhl\u00edkom v elektrickej peci, pri\u010dom sa vytv\u00e1raj\u00fa ingoty metalurgick\u00fdch a abraz\u00edvnych tried, ktor\u00e9 sa pod\u013ea kvality a zam\u00fd\u0161\u013ean\u00e9ho pou\u017eitia ozna\u010duj\u00fa ako a-SiC a b-SiC. Po vytvoren\u00ed sa ingoty rozre\u017e\u00fa na r\u00f4zne ve\u013ekosti a tvary v z\u00e1vislosti od po\u017eadovan\u00fdch aplik\u00e1ci\u00ed a potom sa zmie\u0161aj\u00fa s \u010fal\u0161\u00edmi prvkami, ako je hlin\u00edk alebo dus\u00edk, aby sa dosiahli po\u017eadovan\u00e9 vlastnosti.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon Carbide (SiC) is an extremely hard synthetic compound of silicon and carbon that occurs naturally as the gem moissanite […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","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":[3],"tags":[],"class_list":["post-62","post","type-post","status-publish","format-standard","hentry","category-sic-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/posts\/62","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/comments?post=62"}],"version-history":[{"count":1,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/posts\/62\/revisions"}],"predecessor-version":[{"id":63,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/posts\/62\/revisions\/63"}],"wp:attachment":[{"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/media?parent=62"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/categories?post=62"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/tags?post=62"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}