Karbid k\u0159em\u00edku je st\u00e1le obl\u00edben\u011bj\u0161\u00edm materi\u00e1lem v r\u016fzn\u00fdch pr\u016fmyslov\u00fdch odv\u011btv\u00edch d\u00edky sv\u00fdm p\u016fsobiv\u00fdm mechanick\u00fdm a elektrick\u00fdm vlastnostem, zejm\u00e9na n\u00edzk\u00e9 tepeln\u00e9 rozta\u017enosti a pevnostn\u00edm charakteristik\u00e1m. D\u00edky t\u011bmto vlastnostem je ide\u00e1ln\u00edm kandid\u00e1tem pro v\u00fdrobu zrcadel teleskop\u016f.<\/p>\n
Je p\u0159edstavena metoda v\u00fdroby rekrystalizovan\u00e9ho karbidu k\u0159em\u00edku, kter\u00e1 spo\u010d\u00edv\u00e1 v karbotermick\u00e9 redukci. P\u0159i tomto postupu se t\u011bleso vytvarovan\u00e9 pod tlakem zah\u0159eje na 2 000 \u00b0C za dv\u011b nebo v\u00edce hodin.<\/p>\n
Rekrystalizovan\u00fd karbid k\u0159em\u00edku (RSiC) je pokro\u010dil\u00e1 technick\u00e1 keramika, kter\u00e1 se pou\u017e\u00edv\u00e1 ve vysoce v\u00fdkonn\u00fdch aplikac\u00edch, nap\u0159\u00edklad v leteck\u00e9m a kosmick\u00e9m pr\u016fmyslu. RSiC se vyzna\u010duje v\u00fdjime\u010dn\u00fdmi chemick\u00fdmi a mechanick\u00fdmi vlastnostmi p\u0159i extr\u00e9mn\u00edch teplot\u00e1ch kone\u010dn\u00e9ho pou\u017eit\u00ed; jeho mikrostruktura se skl\u00e1d\u00e1 ze vz\u00e1jemn\u011b propojen\u00fdch deskovit\u00fdch zrn, kter\u00e1 mu dod\u00e1vaj\u00ed vysokou pevnost, hou\u017eevnatost, odolnost proti opot\u0159eben\u00ed a n\u00edzk\u00fd koeficient tepeln\u00e9 rozta\u017enosti, jako\u017e i dobr\u00e9 korozn\u00ed vlastnosti. Je vysoce odoln\u00fd.<\/p>\n
Existuj\u00ed r\u016fzn\u00e9 metody v\u00fdroby hust\u00e9 keramiky SiC, v\u010detn\u011b rekrystalizace, reak\u010dn\u00edho slinov\u00e1n\u00ed, slinov\u00e1n\u00ed v kapaln\u00e9 f\u00e1zi, lisov\u00e1n\u00ed za tepla a izostatick\u00e9ho slinov\u00e1n\u00ed za tepla. A\u010dkoli n\u011bkter\u00e9 z t\u011bchto postup\u016f pou\u017e\u00edvaj\u00ed pomocn\u00e9 sp\u00e9kac\u00ed prost\u0159edky, kter\u00e9 sni\u017euj\u00ed \u010distotu keramiky, v\u0161echny metody produkuj\u00ed hustou keramiku s vynikaj\u00edc\u00edmi tepeln\u00fdmi vlastnostmi v \u0161irok\u00e9m rozsahu teplot.<\/p>\n
SiC se od tradi\u010dn\u00edch \u017e\u00e1ruvzdorn\u00fdch materi\u00e1l\u016f li\u0161\u00ed vysokou teplotn\u00ed pevnost\u00ed a odolnost\u00ed, kter\u00e1 zvy\u0161uje jeho trvanlivost v n\u00e1ro\u010dn\u00fdch podm\u00ednk\u00e1ch, tak\u017ee je ide\u00e1ln\u00ed pro pou\u017eit\u00ed v keramick\u00e9m pr\u016fmyslu. D\u00edky sv\u00e9 vynikaj\u00edc\u00ed pevnosti a odolnosti v\u016f\u010di oxidaci je hutn\u00e1 keramika SiC preferovanou volbou pro pou\u017eit\u00ed jako n\u00e1bytek do pec\u00ed a m\u00e9dia do plynov\u00fdch ho\u0159\u00e1k\u016f i filtr\u016f pevn\u00fdch \u010d\u00e1stic pro dieselov\u00e9 motory; nav\u00edc ji lze nal\u00e9zt i ve vysoce v\u00fdkonn\u00fdch balistick\u00fdch panc\u00ed\u0159\u00edch pro ochranu proti sou\u010dasn\u00fdm i nov\u011b vznikaj\u00edc\u00edm hrozb\u00e1m.<\/p>\n
Rekrystalizovan\u00fd karbid k\u0159em\u00edku (RSiC) je modern\u00ed vysokoteplotn\u00ed \u017e\u00e1ruvzdorn\u00fd keramick\u00fd materi\u00e1l s vynikaj\u00edc\u00edmi vlastnostmi odolnosti proti tepeln\u00fdm \u0161ok\u016fm. RSiC jako takov\u00fd lze nal\u00e9zt v nejr\u016fzn\u011bj\u0161\u00edch aplikac\u00edch, jako jsou plynov\u00e9 ho\u0159\u00e1ky, filtry pevn\u00fdch \u010d\u00e1stic, tepeln\u00e9 v\u00fdm\u011bn\u00edky a tepeln\u00e9 v\u00fdm\u011bn\u00edky. D\u00edky v\u00fdjime\u010dn\u00e9 odolnosti v\u016f\u010di chemik\u00e1li\u00edm a oxidaci, jako\u017e i tuhosti, kter\u00e1 odol\u00e1v\u00e1 v\u00fdkyv\u016fm teplotn\u00ed rozta\u017enosti\/smr\u0161t\u011bn\u00ed, nab\u00edz\u00ed \u0159adu pr\u016fmyslov\u00fdch pou\u017eit\u00ed, v nich\u017e RSiC vynik\u00e1.<\/p>\n
Krom\u011b toho, \u017ee je RSiC extr\u00e9mn\u011b odoln\u00fd materi\u00e1l, vyzna\u010duje se tak\u00e9 vynikaj\u00edc\u00ed pevnost\u00ed p\u0159i pokojov\u00e9 teplot\u011b. Lze jej snadno tvarovat do slo\u017eit\u00fdch tvar\u016f a z\u00e1rove\u0148 odol\u00e1v\u00e1 erozi plamenem a p\u016fsoben\u00ed strusky, je odoln\u00fd proti od\u011bru a ohybu - funguje dokonce jako elektrick\u00fd izolant!<\/p>\n
RSiC se skl\u00e1d\u00e1 z pr\u00e1\u0161kov\u00e9ho karbidu k\u0159em\u00edku, uhl\u00edku a pojiva, kter\u00e9 se sm\u00edchaj\u00ed dohromady a pot\u00e9 se zformuj\u00ed do formy, kde se p\u0159i vysok\u00fdch teplot\u00e1ch slinuj\u00ed, \u010d\u00edm\u017e vznik\u00e1 \u010dist\u00fd materi\u00e1l RSiC. T\u00edmto procesem pr\u00e1\u0161ek rekrystalizuje, zat\u00edmco pojivo se rozpt\u00fdl\u00ed a z\u016fstane \u010dist\u00fd materi\u00e1l RSiC.<\/p>\n
RSiC je jedn\u00edm z nejlep\u0161\u00edch materi\u00e1l\u016f pou\u017e\u00edvan\u00fdch pro vysokoteplotn\u00ed aplikace. D\u00edky sv\u00e9 tuhosti a odolnosti proti korozi a oxidaci je vynikaj\u00edc\u00ed volbou pro n\u00e1bytek do pec\u00ed, jako jsou ty\u010de, desky pro p\u0159\u00edst\u0159e\u0161ky a d\u00edly speci\u00e1ln\u00edch tvar\u016f. Krom\u011b toho lze z tohoto materi\u00e1lu vyrobit tak\u00e9 por\u00e9zn\u00ed formy s otev\u0159en\u00fdmi p\u00f3ry, kter\u00e9 sni\u017euj\u00ed hmotnost a spot\u0159ebu energie a nav\u00edc pom\u00e1haj\u00ed usnadnit vypalov\u00e1n\u00ed porcel\u00e1nov\u00fdch d\u00edl\u016f pro v\u011bt\u0161\u00ed vyu\u017eit\u00ed v peci.<\/p>\n
Karbid k\u0159em\u00edku se vyzna\u010duje v\u00fdjime\u010dnou tepelnou vodivost\u00ed p\u0159i pokojov\u00e9 teplot\u011b, n\u00edzk\u00fdm koeficientem rozta\u017enosti a odolnost\u00ed proti korozi kyselinami, co\u017e z n\u011bj \u010din\u00ed vhodn\u00fd materi\u00e1l pro drsn\u00e9 prost\u0159ed\u00ed. Karbid k\u0159em\u00edku lze tvarovat do r\u016fzn\u00fdch geometrick\u00fdch tvar\u016f a snadno odol\u00e1v\u00e1 i vysok\u00fdm teplot\u00e1m.<\/p>\n
Materi\u00e1l, jako je hl\u00edna, se b\u011b\u017en\u011b pou\u017e\u00edv\u00e1 k v\u00fdrob\u011b d\u00edl\u016f pro pece, jako jsou prov\u011b\u0161ova\u010de, prkna a v\u00e1lce, kter\u00e9 sni\u017euj\u00ed zat\u00ed\u017een\u00ed pece a z\u00e1rove\u0148 zvy\u0161uj\u00ed jej\u00ed vyu\u017eit\u00ed a sni\u017euj\u00ed n\u00e1klady na energii. Nav\u00edc existuj\u00ed por\u00e9zn\u00ed formy, tak\u017ee se snadno p\u0159izp\u016fsob\u00ed jak\u00e9mukoli obrysu vnit\u0159n\u00edho prostoru st\u011bn pece.<\/p>\n
Materi\u00e1l RSiC se od sv\u00fdch keramick\u00fdch koleg\u016f odli\u0161uje chemickou \u010distotou a schopnost\u00ed zachovat si pevnost p\u0159i vysok\u00fdch teplot\u00e1ch, co\u017e z n\u011bj \u010din\u00ed ide\u00e1ln\u00ed materi\u00e1l pro pou\u017eit\u00ed v sou\u010d\u00e1stk\u00e1ch polovodi\u010dov\u00fdch pec\u00ed. Krom\u011b toho se d\u00edky sv\u00e9 vynikaj\u00edc\u00ed chemick\u00e9 \u010distot\u011b a schopnosti zachovat si pevnost p\u0159i vy\u0161\u0161\u00edch teplot\u00e1ch s oblibou pou\u017e\u00edv\u00e1 jako izola\u010dn\u00ed desky pec\u00ed, lopatky a podp\u011bry z\u00e1sobn\u00edk\u016f na desti\u010dky. Krom\u011b toho tento univerz\u00e1ln\u00ed materi\u00e1l slou\u017e\u00ed jako konstruk\u010dn\u00ed d\u00edly odoln\u00e9 proti opot\u0159eben\u00ed v pr\u016fmyslov\u00fdch vysokoteplotn\u00edch pec\u00edch.<\/p>\n
Keramika RSIC je vysoce \u010dist\u00fd materi\u00e1l SiC s por\u00e9zn\u00ed s\u00ed\u0165ovou strukturou, kter\u00fd se vyr\u00e1b\u00ed procesem odpa\u0159ov\u00e1n\u00ed a koagulace a vypaluje se p\u0159i teplot\u011b 2400 \u00b0C. Na rozd\u00edl od pr\u00e1\u0161kov\u00e9ho slinov\u00e1n\u00ed nedoch\u00e1z\u00ed p\u0159i v\u00fdrob\u011b RSIC b\u011bhem infiltra\u010dn\u00ed f\u00e1ze ke smr\u0161\u0165ov\u00e1n\u00ed; to umo\u017e\u0148uje vyr\u00e1b\u011bt velmi velk\u00e9 d\u00edly s p\u0159\u00edsn\u00fdmi tolerancemi ve srovn\u00e1n\u00ed s pr\u00e1\u0161kov\u00fdm slinov\u00e1n\u00edm a z\u00e1rove\u0148 je celkov\u011b levn\u011bj\u0161\u00ed.<\/p>\n
Karbid k\u0159em\u00edku poskytuje v\u00fdjime\u010dnou odolnost proti oxidaci p\u0159i vysok\u00fdch teplot\u00e1ch d\u00edky ochrann\u00e9 vrstv\u011b oxidu k\u0159emi\u010dit\u00e9ho, kter\u00e1 zabra\u0148uje p\u0159\u00edm\u00e9 reakci kysl\u00edku se substr\u00e1tem, tzv. parabolick\u00e9 kinetice. Bohu\u017eel v\u0161ak jeho proces komplikuj\u00ed ne\u010distoty a nuklea\u010dn\u00ed m\u00edsta, jako jsou p\u0159\u00edm\u011bsi ne\u010distot nebo kationty, kter\u00e9 zvy\u0161uj\u00ed tvorbu visk\u00f3zn\u00ed oxidov\u00e9 vrstvy s vy\u0161\u0161\u00ed propustnost\u00ed kysl\u00edku; nav\u00edc rychlost oxidace z\u00e1vis\u00ed na koncentrac\u00edch kationt\u016f p\u0159\u00edtomn\u00fdch na jeho povrchov\u00fdch povlac\u00edch.<\/p>\n
Oxidaci slinut\u00e9ho karbidu k\u0159em\u00edku lze modelovat pomoc\u00ed Deal-Groveova modelu, kter\u00fd je pou\u017eiteln\u00fd pro vlhk\u00e9 i such\u00e9 prost\u0159ed\u00ed, v\u010detn\u011b tenk\u00fdch vrstev o tlou\u0161\u0165ce n\u011bkolika nanometr\u016f. Pomoc\u00ed tohoto p\u0159\u00edstupu jsou snadno dostupn\u00e9 p\u0159esn\u00e9 kinetick\u00e9 \u00fadaje pro tlou\u0161\u0165ky do n\u011bkolika nanometr\u016f; tenk\u00e9 vrstvy v\u0161ak nelze p\u0159izp\u016fsobit line\u00e1rn\u011b-parabolick\u00fdm k\u0159ivk\u00e1m z d\u016fvodu nedostate\u010dn\u00fdch \u00fadaj\u016f.<\/p>\n
Beztlakov\u00fd slinut\u00fd karbid k\u0159em\u00edku (PSSiC) je st\u00e1le obl\u00edben\u011bj\u0161\u00edm materi\u00e1lem pro v\u00fdrobu trysek a ventil\u016f v jadern\u00e9m pr\u016fmyslu, kter\u00e9 jsou \u010dasto vystaveny extr\u00e9mn\u00edm podm\u00ednk\u00e1m vysok\u00e9ho tlaku a teploty, ot\u011bru a korozi. Krom\u011b toho lze PSiC s velk\u00fdm \u00fasp\u011bchem pou\u017e\u00edt tak\u00e9 jako antikorozn\u00ed oblo\u017een\u00ed potrub\u00ed.<\/p>\n
SSIC se vyr\u00e1b\u00ed z velmi jemn\u00e9ho pr\u00e1\u0161ku, kter\u00fd obsahuje sp\u00e9kac\u00ed p\u0159\u00edsady, a pot\u00e9 se zpracov\u00e1v\u00e1 tradi\u010dn\u00edmi keramick\u00fdmi v\u00fdrobn\u00edmi postupy a sp\u00e9k\u00e1 se p\u0159i teplot\u011b 2 000 \u00b0C. Tato technologie umo\u017e\u0148uje masovou v\u00fdrobu p\u0159i ni\u017e\u0161\u00edch n\u00e1kladech ne\u017e tradi\u010dn\u00ed metody.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide is an increasingly popular material across industries due to its impressive mechanical and electrical properties, particularly its low thermal expansion rate and strength characteristics. Due to this property it makes an ideal candidate for telescope mirror manufacturing. A method for producing recrystallized silicon carbide is presented, consisting of carbothermic reduction. This process heats […]<\/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-70","post","type-post","status-publish","format-standard","hentry","category-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/posts\/70","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/comments?post=70"}],"version-history":[{"count":1,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/posts\/70\/revisions"}],"predecessor-version":[{"id":71,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/posts\/70\/revisions\/71"}],"wp:attachment":[{"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/media?parent=70"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/categories?post=70"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/tags?post=70"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}