Karbid krem\u00edka (SiC) je v\u00fdnimo\u010dn\u00fd materi\u00e1l s vynikaj\u00facimi fyzik\u00e1lnymi vlastnos\u0165ami. Je odoln\u00fd vo\u010di vysok\u00fdm teplot\u00e1m, kor\u00f3zii a opotrebeniu a z\u00e1rove\u0148 sa vyzna\u010duje n\u00edzkou mierou tepelnej roz\u0165a\u017enosti.<\/p>\n
Moissanit sa v pr\u00edrode vyskytuje ako miner\u00e1l len vo ve\u013emi obmedzen\u00fdch mno\u017estv\u00e1ch a odvtedy sa hromadne vyr\u00e1ba pomocou procesu elektrick\u00e9ho \u0161ar\u017eov\u00e9ho tavenia, ktor\u00fd vyvinul Edward G. Acheson a ktor\u00fd sa pou\u017e\u00edva dodnes.<\/p>\n
Karbid krem\u00edka pon\u00faka v\u00fdnimo\u010dn\u00fa chemick\u00fa a mechanick\u00fa odolnos\u0165 v \u0161irokom teplotnom rozsahu, odol\u00e1va kor\u00f3zii a oderu v\u010faka vysok\u00e9mu modulu pru\u017enosti a n\u00edzkemu koeficientu tepelnej roz\u0165a\u017enosti. Okrem toho karbid krem\u00edka vykazuje dobr\u00fa odolnos\u0165 vo\u010di tepeln\u00fdm \u0161okom, hoci v men\u0161ej miere ako kon\u0161truk\u010dn\u00e1 keramika na b\u00e1ze zirk\u00f3nu.<\/p>\n
SiC je vo v\u0161eobecnosti elektrick\u00fd izolant; pri kontrolovanom prid\u00e1van\u00ed ne\u010dist\u00f4t sa v\u0161ak m\u00f4\u017ee sta\u0165 elektricky vodiv\u00fdm. Pri dopovan\u00ed hlin\u00edkom, b\u00f3rom alebo g\u00e1liom sa st\u00e1va polovodi\u010dom typu P, zatia\u013e \u010do dopovanie dus\u00edkom alebo fosforom vedie k vzniku vlastnost\u00ed polovodi\u010da typu N.<\/p>\n
\u010cist\u00fd priemyseln\u00fd SiC m\u00e1 hned\u00fa a\u017e \u010diernu farbu v d\u00f4sledku pr\u00edmes\u00ed \u017eeleza. Ako polytipov\u00fd polovodi\u010dov\u00fd materi\u00e1l sa jeho kry\u0161t\u00e1lov\u00e9 \u0161trukt\u00fary l\u00ed\u0161ia v z\u00e1vislosti od toho, ako sa at\u00f3my uhl\u00edka a krem\u00edka usporad\u00favaj\u00fa do tetra\u00e9drov; v\u010faka tomu sa pri kon\u0161tantn\u00fdch teplot\u00e1ch m\u00f4\u017ee spr\u00e1va\u0165 bu\u010f ako izolant, alebo ako vodi\u010d; navy\u0161e je nerozpustn\u00fd vo vode aj v alkohole, ale odoln\u00fd vo\u010di v\u00e4\u010d\u0161ine organick\u00fdch kysel\u00edn, z\u00e1sad a sol\u00ed.<\/p>\n
Keramika z karbidu krem\u00edka nach\u00e1dza uplatnenie v mnoh\u00fdch odvetviach: od br\u00fasnych a rezac\u00edch n\u00e1strojov, kon\u0161truk\u010dn\u00fdch materi\u00e1lov (nepriestreln\u00e9 vesty a kompozitn\u00e9 pancierovanie), automobilov\u00fdch dielov, ako s\u00fa brzdov\u00e9 kot\u00fa\u010de a bleskozvody, a\u017e po prostredia s vysokou odolnos\u0165ou vo\u010di kor\u00f3zii a oderu, ako s\u00fa petrochemick\u00e9 v\u00fdrobn\u00e9 z\u00e1vody alebo syst\u00e9my ods\u00edrenia spal\u00edn.<\/p>\n
V\u00fdkonov\u00e9 prvky z SiC vyu\u017e\u00edvaj\u00fa vlastnosti polovodi\u010da so \u0161irokou \u0161\u00edrkou zak\u00e1zan\u00e9ho p\u00e1sma, v\u010faka \u010domu dok\u00e1\u017eu pracova\u0165 pri vy\u0161\u0161\u00edch nap\u00e4tiach, \u010do umo\u017e\u0148uje vytv\u00e1ra\u0165 kompaktnej\u0161ie syst\u00e9my na konverziu energie so zn\u00ed\u017een\u00fdmi stratami energie a krat\u0161\u00edmi \u010dasmi konverzie. Okrem toho prvky z SiC prekonali svoje krem\u00edkov\u00e9 n\u00e1protivky, pokia\u013e ide o sp\u00ednac\u00ed pr\u00fad a teplotn\u00fa odolnos\u0165, \u010do v kone\u010dn\u00fdch produktoch vedie k v\u00fdznamn\u00e9mu zv\u00fd\u0161eniu \u00fa\u010dinnosti.<\/p>\n
Karbid krem\u00edka (SiC) v\u010faka svojej jedine\u010dnej kombin\u00e1cii fyzik\u00e1lnych a elektronick\u00fdch vlastnost\u00ed r\u00fdchlo prin\u00e1\u0161a revol\u00faciu v oblasti v\u00fdkonovej elektroniky. MOSFETy a Schottkyho di\u00f3dy vyroben\u00e9 z SiC s\u00fa \u0161iroko vyu\u017e\u00edvan\u00e9 technol\u00f3gie v\u00fdkonov\u00fdch polovodi\u010dov a tvoria k\u013e\u00fa\u010dov\u00e9 komponenty v trak\u010dn\u00fdch meni\u010doch a palubn\u00fdch nab\u00edja\u010dk\u00e1ch elektrick\u00fdch vozidiel, ako aj v DC\/DC meni\u010doch nach\u00e1dzaj\u00facich sa na nab\u00edjac\u00edch staniciach \u2013 to sa prejavuje v zlep\u0161en\u00ed dojazdu elektrick\u00fdch vozidiel a zv\u00fd\u0161en\u00ed \u00fa\u010dinnosti priemyseln\u00fdch aplik\u00e1ci\u00ed.<\/p>\n
Z karbidu krem\u00edka sa daj\u00fa vyr\u00e1ba\u0165 r\u00f4zne materi\u00e1ly pre rozmanit\u00e9 \u00fa\u010dely. Strojn\u00ed in\u017einieri ho vyu\u017e\u00edvaj\u00fa ako pokro\u010dil\u00fa keramiku pre jeho pevnos\u0165, tvrdos\u0165, odolnos\u0165 proti kor\u00f3zii a opotrebeniu, rovnako ako elektrotechnici, ktor\u00ed vyu\u017e\u00edvaj\u00fa jeho v\u00fdnimo\u010dn\u00e9 elektrick\u00e9 vlastnosti v polovodi\u010doch. Okrem toho karbid krem\u00edka zohr\u00e1va k\u013e\u00fa\u010dov\u00fa \u00falohu v kompozitn\u00fdch pancieroch, ako je napr\u00edklad pancier Chobham, alebo v keramick\u00fdch platniach pou\u017e\u00edvan\u00fdch v nepriestreln\u00fdch vest\u00e1ch.<\/p>\n
Edward Goodrich Acheson prv\u00fdkr\u00e1t umelo syntetizoval SiC v roku 1891 pri pokuse o v\u00fdrobu syntetick\u00fdch diamantov. Hoci vytvoril tvrd\u00e9, modro\u010dierne kry\u0161t\u00e1ly, ktor\u00e9 nazval \u201ecarborundum\u201c (vzh\u013eadom na to, \u017ee ich nespr\u00e1vne identifikoval ako zl\u00fa\u010deninu podobn\u00fa korundu), jeho met\u00f3da sa odvtedy stala z\u00e1kladom v\u00e4\u010d\u0161iny s\u00fa\u010dasnej v\u00fdroby SiC.<\/p>\n
\u010cistota kry\u0161t\u00e1lov vyroben\u00fdch v Achesonovej peci z\u00e1vis\u00ed od ich vzdialenosti od grafitov\u00e9ho odporov\u00e9ho zdroja tepla; tie, ktor\u00e9 s\u00fa k nemu najbli\u017e\u0161ie, b\u00fdvaj\u00fa \u010d\u00edre, zatia\u013e \u010do tie vzdialenej\u0161ie maj\u00fa tendenciu tmavn\u00fa\u0165 v d\u00f4sledku dopovania dus\u00edkom alebo hlin\u00edkom, \u010do zni\u017euje ich vodivos\u0165. Ve\u013ek\u00e9 monokry\u0161t\u00e1ly sa komer\u010dne vyr\u00e1baj\u00fa pomocou modifikovan\u00fdch Lelyho procesov alebo fyzik\u00e1lneho transportu pary.<\/p>\n
Prach z karbidu krem\u00edka m\u00f4\u017ee by\u0165 dr\u00e1\u017ediv\u00fdm faktorom, ktor\u00fd m\u00f4\u017ee prispieva\u0165 k neprogres\u00edvnej p\u013e\u00facnej fibr\u00f3ze a sp\u00f4sobi\u0165 podr\u00e1\u017edenie nosa a o\u010d\u00ed. Dlhodob\u00e1 expoz\u00edcia m\u00f4\u017ee dokonca vies\u0165 k pneumokoni\u00f3ze \u2013 chronick\u00e9mu ochoreniu p\u013e\u00fac, ktor\u00e9ho pr\u00edznaky zah\u0155\u0148aj\u00fa abnormality na r\u00f6ntgenov\u00fdch sn\u00edmkach hrudn\u00edka a zhor\u0161enie p\u013e\u00facnych funkci\u00ed; navy\u0161e zvy\u0161uje riziko tuberkul\u00f3zy.<\/p>\n
V\u010faka svojej mimoriadnej tvrdosti a tuhosti poskytuje pancier z uhl\u00edkov\u00fdch vl\u00e1kien balistick\u00fa ochranu pri ove\u013ea ni\u017e\u0161ej hmotnosti v\u00fdrobku v porovnan\u00ed s tradi\u010dn\u00fdmi oce\u013eov\u00fdmi rie\u0161eniami.<\/p>\n
V jadrov\u00fdch aplik\u00e1ci\u00e1ch sa vyu\u017e\u00edva pl\u00e1\u0161\u0165 z SiC v\u010faka jeho vynikaj\u00facej odolnosti vo\u010di o\u017eiareniu, ktor\u00e1 prekon\u00e1va vlastnosti materi\u00e1lu Zry-4 pri \u00farovniach prim\u00e1rneho Trescovho nap\u00e4tia a nad nimi, pri\u010dom si st\u00e1le zachov\u00e1va prijate\u013en\u00fa rezervu pre odstavenie reaktora. Okrem toho sa vyzna\u010duje ni\u017e\u0161\u00edm prierezom absorpcie neutr\u00f3nov; obaly z materi\u00e1lov SS-310 aj FeCrAl vykazuj\u00fa pri BOL o nie\u010do negat\u00edvnej\u0161ie hodnoty MTC ako SiC; tieto hodnoty sa v\u0161ak po 5 s od LBLOCA v\u00fdrazne zni\u017euj\u00fa v d\u00f4sledku Dopplerovho roz\u0161\u00edrenia plodn\u00fdch neutr\u00f3nov.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide (SiC) is an exceptional material with outstanding physical properties. It is resistant to high temperatures, corrosion and wear while possessing low thermal expansion rates. Moissanite occurs naturally in very limited quantities as a mineral, and has since been mass produced via Edward G. Acheson’s electric batch furnace process which continues to this day. […]<\/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-178","post","type-post","status-publish","format-standard","hentry","category-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/178","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=178"}],"version-history":[{"count":1,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":179,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/178\/revisions\/179"}],"wp:attachment":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/media?parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/categories?post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/tags?post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}