Karbid krem\u00edka je jedn\u00fdm z najtvrd\u0161\u00edch a najpevnej\u0161\u00edch materi\u00e1lov na Zemi, zn\u00e1my svojou pevnos\u0165ou, tepelnou vodivos\u0165ou a odolnos\u0165ou vo\u010di kyselin\u00e1m \u2013 v\u010faka t\u00fdmto vlastnostiam je vhodn\u00fd na pou\u017eitie v r\u00f4znych priemyseln\u00fdch odvetviach.<\/p>\n
SiC je pr\u00edrodn\u00fd miner\u00e1l zn\u00e1my pod n\u00e1zvom moissanit; od roku 1893 sa v\u0161ak hromadne vyr\u00e1ba vo forme pr\u00e1\u0161ku a kry\u0161t\u00e1lov na pou\u017eitie ako br\u00fasivo a na \u010fal\u0161ie priemyseln\u00e9 \u00fa\u010dely, ako aj ako substr\u00e1t pre polovodi\u010de.<\/p>\n
Karbid krem\u00edka sa vyzna\u010duje jedine\u010dn\u00fdmi vlastnos\u0165ami, v\u010faka ktor\u00fdm patr\u00ed medzi najv\u00fdhodnej\u0161ie priemyseln\u00e9 materi\u00e1ly. Medzi pokro\u010dil\u00fdmi keramick\u00fdmi materi\u00e1lmi vynik\u00e1 najm\u00e4 svojou tvrdos\u0165ou a n\u00edzkou hmotnos\u0165ou; okrem toho m\u00e1 vynikaj\u00facu tepeln\u00fa vodivos\u0165 a n\u00edzku mieru tepelnej roz\u0165a\u017enosti; navy\u0161e \u013eahko odol\u00e1va er\u00f3zii a oteru \u2013 v\u010faka t\u00fdmto vlastnostiam je vhodn\u00fd na pou\u017eitie v syst\u00e9moch v\u00fdsteliek mlynov, komponentov cykl\u00f3nov, striekac\u00edch d\u00fdz a extrud\u00e9rov.<\/p>\n
Karbid krem\u00edka v \u010distom stave je elektrick\u00fd izolant. Pridan\u00edm kontrolovan\u00fdch ne\u010dist\u00f4t v\u0161ak mo\u017eno dosiahnu\u0165, aby sa karbid krem\u00edka spr\u00e1val ako polovodi\u010dov\u00e9 zariadenie \u2013 hlin\u00edk, b\u00f3r a g\u00e1lium m\u00f4\u017eu vytvori\u0165 zariadenia typu P, zatia\u013e \u010do dus\u00edk a fosfor ved\u00fa k vzniku zariaden\u00ed typu N.<\/p>\n
Tranzistory na b\u00e1ze SiC sa vyzna\u010duj\u00fa vy\u0161\u0161\u00edm prahov\u00fdm nap\u00e4t\u00edm a ni\u017e\u0161\u00edm odporom pri zapnut\u00ed v porovnan\u00ed so svojimi krem\u00edkov\u00fdmi n\u00e1protivkami, \u010do umo\u017e\u0148uje dosahova\u0165 vy\u0161\u0161ie sp\u00ednacie frekvencie a vytv\u00e1ra\u0165 men\u0161ie syst\u00e9my v\u00fdkonovej elektroniky. Meni\u010de na nab\u00edjanie elektrick\u00fdch vozidiel m\u00f4\u017eu vyu\u017e\u00edva\u0165 SiC na zn\u00ed\u017eenie rozmerov a hmotnosti svojich syst\u00e9mov riadenia v\u00fdkonu a na zv\u00fd\u0161enie dojazdu.<\/p>\n
Karbid krem\u00edka, be\u017ene ozna\u010dovan\u00fd ako SiC, je mimoriadne tvrd\u00e1, synteticky vyr\u00e1ban\u00e1 kry\u0161talick\u00e1 zl\u00fa\u010denina pozost\u00e1vaj\u00faca z krem\u00edka a uhl\u00edka, ktor\u00e1 je chemicky inertn\u00e1 a odoln\u00e1 vo\u010di kor\u00f3zii (hoci je n\u00e1chyln\u00e1 na p\u00f4sobenie kyseliny chlorovod\u00edkovej, s\u00edrovej alebo in\u00fdch kysel\u00edn).<\/p>\n
Karbid krem\u00edka sa vyzna\u010duje mnoh\u00fdmi v\u00fdhodn\u00fdmi vlastnos\u0165ami, v\u010faka ktor\u00fdm je cenn\u00fdm materi\u00e1lom, medzi ktor\u00e9 patr\u00ed vysok\u00e1 pevnos\u0165 a tuhos\u0165, n\u00edzka miera tepelnej roz\u0165a\u017enosti, odolnos\u0165 vo\u010di oxid\u00e1cii a oderu, ako aj zachovanie elastickej pevnosti aj pri vysok\u00fdch teplot\u00e1ch. V\u010faka tejto kombin\u00e1cii keramick\u00fdch a polovodi\u010dov\u00fdch vlastnost\u00ed je vynikaj\u00facou vo\u013ebou ako pre kon\u0161truk\u010dn\u00fa keramiku, tak aj pre br\u00fasne materi\u00e1ly.<\/p>\n
\u010cist\u00fd SiC je bezfarebn\u00fd kry\u0161t\u00e1l. Pridan\u00edm r\u00f4znych mno\u017estiev ne\u010dist\u00f4t je v\u0161ak mo\u017en\u00e9 zmeni\u0165 jeho elektrick\u00e9 vlastnosti tak, aby zodpovedali vlastnostiam polovodi\u010da. Vrstven\u00e9 \u0161trukt\u00fary v kry\u0161t\u00e1loch vytv\u00e1raj\u00fa r\u00f4zne polytypy karbidu krem\u00edka s jedine\u010dn\u00fdmi kry\u0161t\u00e1lov\u00fdmi \u0161trukt\u00farami; naj\u010dastej\u0161ie sa vyskytuje hexagon\u00e1lna kry\u0161t\u00e1lov\u00e1 \u0161trukt\u00fara 6H-SiC, ktor\u00e1 je pod\u013ea spolo\u010dnosti Wolfspeed vhodn\u00e1 pre v\u00fdkonov\u00fa elektroniku v\u010faka \u0161irokej \u0161\u00edrke zak\u00e1zan\u00e9ho p\u00e1sma 1,12 eV.<\/p>\n
Jedine\u010dn\u00e9 fyzik\u00e1lne a elektronick\u00e9 vlastnosti karbidu krem\u00edka prin\u00e1\u0161aj\u00fa revol\u00faciu v oblasti v\u00fdkonovej elektroniky. Nov\u00e9 zariadenia vyroben\u00e9 s vyu\u017eit\u00edm SiC sa v porovnan\u00ed so svojimi predchodcami vyzna\u010duj\u00fa vy\u0161\u0161ou spo\u013eahlivos\u0165ou, ni\u017e\u0161\u00edmi stratami v\u00fdkonu, r\u00fdchlej\u0161\u00edmi sp\u00ednac\u00edmi \u010dasmi a vy\u0161\u0161ou energetickou \u00fa\u010dinnos\u0165ou.<\/p>\n
\u010cist\u00fd karbid krem\u00edka sa spr\u00e1va ako elektrick\u00fd izolant; dopovanie kontrolovan\u00fdmi ne\u010distotami (tzv. dopantmi) v\u0161ak za ur\u010dit\u00fdch okolnost\u00ed umo\u017e\u0148uje, aby viedol elektrick\u00fd pr\u00fad. Dopovanie hlin\u00edkom, b\u00f3rom a g\u00e1liom vedie k vzniku polovodi\u010dov typu P; dopovanie fosforom a dus\u00edkom vedie k vzniku polovodi\u010dov typu N.<\/p>\n
At\u00f3mov\u00e1 \u0161trukt\u00fara karbidu krem\u00edka sa podob\u00e1 \u0161trukt\u00fare at\u00f3mov uhl\u00edka a krem\u00edka, ktor\u00e9 s\u00fa kovalentne spojen\u00e9 do dvoch prim\u00e1rnych koordina\u010dn\u00fdch tetra\u00e9drov, pri\u010dom \u0161tyri at\u00f3my uhl\u00edka a \u0161tyri at\u00f3my krem\u00edka s\u00fa kovalentne viazan\u00e9 medzi sebou a tvoria dva prim\u00e1rne koordina\u010dn\u00e9 tetra\u00e9dre \u2013 z ktor\u00fdch ka\u017ed\u00fd pozost\u00e1va zo \u0161tyroch at\u00f3mov uhl\u00edka a \u0161tyroch at\u00f3mov krem\u00edka kovalentne navz\u00e1jom spojen\u00fdch \u2013 kovalentne viazan\u00fdch kovalentn\u00fdmi v\u00e4zbami. D\u00e1 sa z neho vyr\u00e1ba\u0165 v r\u00f4znych tvaroch; zvy\u010dajne sa rozomelie na jemn\u00fd pr\u00e1\u0161ok a potom sa zmie\u0161a s neoxidov\u00fdmi sp\u00e1jac\u00edmi prostriedkami na spekanie, ako s\u00fa organokrem\u00edkov\u00e9 pojiv\u00e1, \u010d\u00edm vznikne pastovit\u00e1 zmes, ktor\u00fa je mo\u017en\u00e9 n\u00e1sledne tvarova\u0165 pomocou procesov studenej izostatick\u00e9ho lisovania alebo extrudovania \u2013 \u0161iroko sa pou\u017e\u00edva v rezn\u00fdch n\u00e1strojoch, kon\u0161truk\u010dn\u00fdch materi\u00e1loch (nepriestreln\u00e9 vesty\/kompozitn\u00e9 pancierov\u00e9 materi\u00e1ly), v\u00fdrobe automobilov\u00fdch dielov, v\u00fdrobe zrkadlov\u00fdch materi\u00e1lov, ako aj zrkadlov\u00fdch materi\u00e1lov pre astronomick\u00e9 \u010falekoh\u013eady.<\/p>\n
Karbid krem\u00edka patr\u00ed medzi najtvrd\u0161ie a najpevnej\u0161ie modern\u00e9 keramick\u00e9 materi\u00e1ly, ktor\u00e9 sa vyzna\u010duj\u00fa n\u00edzkou mierou tepelnej roz\u0165a\u017enosti, odolnos\u0165ou vo\u010di kyselin\u00e1m, odolnos\u0165ou vo\u010di er\u00f3zii a vynikaj\u00facou odolnos\u0165ou vo\u010di opotrebeniu.<\/p>\n
Pri v\u00fdrobe karbidu krem\u00edka prebiehaj\u00fa r\u00f4zne chemick\u00e9 reakcie, naj\u010dastej\u0161ie sa v\u0161ak vyu\u017e\u00edva Achesonov proces. Ten spo\u010d\u00edva v zahrievan\u00ed zmesi oxidu kremi\u010dit\u00e9ho a koksu na vysok\u00e9 teploty, a\u017e k\u00fdm medzi ich zlo\u017ekami ned\u00f4jde k chemickej reakcii a nevytvoria sa kry\u0161t\u00e1ly.<\/p>\n
Tieto kry\u0161t\u00e1ly sa n\u00e1sledne rozomel\u00fa na jemn\u00fd pr\u00e1\u0161ok a zmie\u0161aj\u00fa s neoxidov\u00fdmi sp\u00e1jadlami na spekanie, ako s\u00fa organokrem\u00edkov\u00e9 viazacie l\u00e1tky, \u010d\u00edm vznikne pasta, ktor\u00e1 sa zhutn\u00ed a tvaruje extrudovan\u00edm alebo izostatick\u00fdm lisovan\u00edm za studena.<\/p>\n
Karbid krem\u00edka je v\u010faka svojej tvrdosti a odolnosti nenahradite\u013en\u00fdm materi\u00e1lom v modernej klenotn\u00edckej v\u00fdrobe. V\u010faka svojej univerz\u00e1lnosti sa pou\u017e\u00edva na najr\u00f4znej\u0161ie \u00fa\u010dely \u2013 od v\u00fdmuroviek pec\u00ed, rezac\u00edch n\u00e1strojov a br\u00fasnych kot\u00fa\u010dov, cez diely odoln\u00e9 vo\u010di opotrebeniu v \u010derpadl\u00e1ch a raketov\u00fdch motoroch, a\u017e po komponenty v\u00fdkonovej elektroniky s n\u00edzkym odporom, ako aj na ten\u0161ie do\u0161ti\u010dky v\u010faka ni\u017e\u0161iemu prierazov\u00e9mu nap\u00e4tiu.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide is one of the hardest and strongest materials on Earth, known for its strength, thermal conductivity and acid resistance – qualities which make it suitable for applications across industries. SiC is a naturally-occurring mineral known as moissanite; however, since 1893 it has been mass produced as powder and crystal form for use as […]<\/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-112","post","type-post","status-publish","format-standard","hentry","category-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/112","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/comments?post=112"}],"version-history":[{"count":1,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/112\/revisions"}],"predecessor-version":[{"id":113,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/112\/revisions\/113"}],"wp:attachment":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/media?parent=112"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/categories?post=112"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/tags?post=112"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}