Karbid k\u0159em\u00edku je nenahraditeln\u00fd konstruk\u010dn\u00ed keramick\u00fd materi\u00e1l d\u00edky sv\u00e9 v\u00fdjime\u010dn\u00e9 pevnosti p\u0159i vysok\u00fdch teplot\u00e1ch a odolnosti v\u016f\u010di oxidaci, d\u00edky \u010demu\u017e je nepostradateln\u00fd v oblasti stroj\u00edrensk\u00e9 v\u00fdroby, leteck\u00e9 techniky a informa\u010dn\u00ed elektroniky.<\/p>\n
Reak\u010dn\u00ed sp\u00e9k\u00e1n\u00ed nab\u00edz\u00ed n\u00edzk\u00e9 teploty a kr\u00e1tk\u00e9 doby sp\u00e9k\u00e1n\u00ed p\u0159i v\u00fdrob\u011b tvar\u016f bl\u00edzk\u00fdch \u010dist\u00e9 velikosti, ale je omezeno nerovnom\u011brn\u00fdm rozlo\u017een\u00edm hustoty, prask\u00e1n\u00edm sp\u00e9kan\u00fdch v\u00fdrobk\u016f a nedostate\u010dnou penetrac\u00ed k\u0159em\u00edku b\u011bhem sp\u00e9k\u00e1n\u00ed.<\/p>\n
Karbid k\u0159em\u00edku je extr\u00e9mn\u011b tvrd\u00fd a hou\u017eevnat\u00fd keramick\u00fd materi\u00e1l proslul\u00fd svou vynikaj\u00edc\u00ed pevnost\u00ed p\u0159i vysok\u00fdch teplot\u00e1ch, odolnost\u00ed proti opot\u0159eben\u00ed a chemickou oxidac\u00ed. D\u00edky t\u011bmto vlastnostem nach\u00e1z\u00ed karbid k\u0159em\u00edku uplatn\u011bn\u00ed v mnoha pr\u016fmyslov\u00fdch aplikac\u00edch v\u010detn\u011b jadern\u00fdch elektr\u00e1ren, pec\u00ed, trysek proudov\u00fdch motor\u016f, raketov\u00fdch trysek a v\u00fdroby pap\u00edru.<\/p>\n
Jedn\u00edm ze zp\u016fsob\u016f, jak zlep\u0161it mechanick\u00e9 vlastnosti slinut\u00e9ho karbidu k\u0159em\u00edku p\u0159i vysok\u00fdch teplot\u00e1ch, je p\u0159id\u00e1n\u00ed p\u0159\u00edsad, jako je hlin\u00edk, b\u00f3r a uhl\u00edk (SiC-ABC), kter\u00e9 zvy\u0161uj\u00ed odolnost proti te\u010den\u00ed. Tyto p\u0159\u00edsady m\u011bn\u00ed energie na hranic\u00edch zrn a povrchov\u00e9 energie a z\u00e1rove\u0148 zvy\u0161uj\u00ed rychlost objemov\u00e9 dif\u00faze a br\u00e1n\u00ed tvorb\u011b skla na hranic\u00edch zrn.<\/p>\n
Dal\u0161\u00edm zp\u016fsobem, jak zv\u00fd\u0161it mechanick\u00e9 vlastnosti, je beztlakov\u00e9 sp\u00e9k\u00e1n\u00ed, kter\u00e9 zahrnuje sp\u00e9k\u00e1n\u00ed pr\u00e1\u0161kov\u00fdch kompakt\u016f SiC bez pou\u017eit\u00ed vn\u011bj\u0161\u00edho tlaku. V\u00fdhoda t\u00e9to metody spo\u010d\u00edv\u00e1 v eliminaci zm\u011bn hustoty zp\u016fsoben\u00fdch tradi\u010dn\u00edmi metodami sp\u00e9k\u00e1n\u00ed za tepla, kter\u00e9 maj\u00ed za n\u00e1sledek v\u00fdrazn\u00e9 rozm\u011brov\u00e9 zm\u011bny a sn\u00ed\u017eenou kvalitu v\u00fdrobk\u016f, a tak\u00e9 vytv\u00e1\u0159\u00ed hustoty bli\u017e\u0161\u00ed teoretick\u00fdm hodnot\u00e1m ne\u017e kdykoli p\u0159edt\u00edm.<\/p>\n
Karbid k\u0159em\u00edku vykazuje vynikaj\u00edc\u00ed odolnost proti chemick\u00e9 korozi v \u0161irok\u00e9m rozsahu prost\u0159ed\u00ed a\u017e do teploty 1700 stup\u0148\u016f C, jako je such\u00fd kysl\u00edk, hork\u00e9 plynn\u00e9 p\u00e1ry a kapaln\u00e9 soli a kovy, jako\u017e i roztaven\u00e9 soli a strusky uheln\u00e9ho popela.<\/p>\n
Slinut\u00fd karbid k\u0159em\u00edku m\u00e1 d\u00edky sv\u00e9 struktu\u0159e a kvalit\u011b povrchu vynikaj\u00edc\u00ed odolnost proti korozi. Tento materi\u00e1l se m\u016f\u017ee pochlubit silnou odolnost\u00ed proti erozi (klouz\u00e1n\u00ed), mechanick\u00e9 pevnosti, tepeln\u00fdm \u0161ok\u016fm a opot\u0159eben\u00ed.<\/p>\n
Vysokoteplotn\u00ed slinut\u00fd materi\u00e1l z karbidu k\u0159em\u00edku XICAR (b\u011b\u017en\u011b ozna\u010dovan\u00fd jako alternativa Hexoloy SE) se uk\u00e1zal jako vysoce odoln\u00fd v\u016f\u010di chemick\u00e9 korozi v kysel\u00e9m prost\u0159ed\u00ed, jako je koncentrovan\u00e1 HCl a HNO3, p\u0159i\u010dem\u017e vzorky o\u0161et\u0159en\u00e9 Y2O3 maj\u00ed vy\u0161\u0161\u00ed odolnost ne\u017e vzorky s pou\u017eit\u00edm pomocn\u00e9ho slinut\u00ed MgO.<\/p>\n
Reak\u010dn\u011b v\u00e1zan\u00fd slinut\u00fd karbid k\u0159em\u00edku, b\u011b\u017en\u011b ozna\u010dovan\u00fd jako samovazn\u00fd karbid k\u0159em\u00edku, se vyr\u00e1b\u00ed reakc\u00ed por\u00e9zn\u00edho keramick\u00e9ho t\u011blesa obsahuj\u00edc\u00edho uhl\u00edk s tekut\u00fdm k\u0159em\u00edkem. Tato sm\u011bs pronik\u00e1 do keramick\u00e9ho t\u011blesa, reaguje s grafitem za vzniku b-SiC a pot\u00e9 se spojuje se st\u00e1vaj\u00edc\u00edmi \u010d\u00e1sticemi a-SiC za \u00fa\u010delem vytvo\u0159en\u00ed reak\u010dn\u011b slinut\u00e9ho karbidu k\u0159em\u00edku s plnou hustotou a r\u016fzn\u00fdmi tvary, kter\u00e9 jsou t\u00edmto procesem dostupn\u00e9.<\/p>\n
Karbid k\u0159em\u00edku je jedn\u00edm z nejpevn\u011bj\u0161\u00edch keramick\u00fdch materi\u00e1l\u016f. Karbid k\u0159em\u00edku se vyzna\u010duje vynikaj\u00edc\u00ed pevnost\u00ed p\u0159i vysok\u00fdch teplot\u00e1ch a odolnost\u00ed proti oxidaci, a proto je vynikaj\u00edc\u00ed volbou materi\u00e1lu pro pou\u017eit\u00ed v mnoha pr\u016fmyslov\u00fdch aplikac\u00edch.<\/p>\n
Keramiku z karbidu k\u0159em\u00edku lze obvykle vyr\u00e1b\u011bt bu\u010f beztlakov\u00fdm sp\u00e9k\u00e1n\u00edm, nebo reak\u010dn\u00edm spojov\u00e1n\u00edm, a spole\u010dnost Saint-Gobain Performance Ceramics & Refractories nab\u00edz\u00ed oba typy, kter\u00e9 vyhovuj\u00ed \u0159ad\u011b kone\u010dn\u00fdch aplikac\u00ed.<\/p>\n
Beztlakov\u00fd slinut\u00fd karbid k\u0159em\u00edku se vyr\u00e1b\u00ed kombinac\u00ed jemn\u00fdch \u010d\u00e1stic pr\u00e1\u0161ku SiC s neoxidov\u00fdmi sp\u00e9kac\u00edmi p\u0159\u00edsadami a slinov\u00e1n\u00edm p\u0159i teplot\u00e1ch vy\u0161\u0161\u00edch ne\u017e 2000 \u00b0C v inertn\u00ed atmosf\u00e9\u0159e, \u010d\u00edm\u017e vznik\u00e1 materi\u00e1l s vysokou hustotou, vynikaj\u00edc\u00ed odolnost\u00ed proti oxidaci, korozi a mechanick\u00fdmi vlastnostmi.<\/p>\n
Reak\u010dn\u00ed slinov\u00e1n\u00ed je nov\u00fd proces v\u00fdroby keramiky z karbidu k\u0159em\u00edku (SiC), kter\u00fd nab\u00edz\u00ed v\u00fdhody, jako je hust\u00e1 struktura, ni\u017e\u0161\u00ed teplota zpracov\u00e1n\u00ed, tvarov\u00e1 st\u00e1lost, n\u00edzk\u00e9 n\u00e1klady a vy\u0161\u0161\u00ed \u010distota. Bohu\u017eel v\u0161ak jeho pevnost v ohybu zdaleka nedosahuje pevnosti standardn\u00edho slinut\u00e9ho SiC kv\u016fli velikosti zbytkov\u00e9ho uhl\u00edku (Si) v jeho mikrostruktu\u0159e.<\/p>\n
Keramika ze slinut\u00e9ho karbidu k\u0159em\u00edku pat\u0159\u00ed k nejtvrd\u0161\u00edm a nejpevn\u011bj\u0161\u00edm keramick\u00fdm materi\u00e1l\u016fm, p\u0159i\u010dem\u017e si zachov\u00e1v\u00e1 pevnost i p\u0159i extr\u00e9mn\u011b vysok\u00fdch teplot\u00e1ch - je tedy vynikaj\u00edc\u00ed volbou pro aplikace, kde je kl\u00ed\u010dov\u00e1 odolnost v\u016f\u010di vysok\u00fdm teplot\u00e1m.<\/p>\n
SSIC vykazuje t\u00e9m\u011b\u0159 konstantn\u00ed pevnost v \u0161irok\u00e9m rozsahu teplot a zachov\u00e1v\u00e1 si hou\u017eevnatost i p\u0159i vysok\u00e9m tlaku, co\u017e z n\u011bj \u010din\u00ed velmi obl\u00edben\u00fd materi\u00e1l pro vysoce v\u00fdkonn\u00e9 sou\u010d\u00e1sti \u010derpadel a dal\u0161\u00ed d\u016fle\u017eit\u00e9 sou\u010d\u00e1sti za\u0159\u00edzen\u00ed.<\/p>\n
SSIC se vyr\u00e1b\u011bj\u00ed b\u011b\u017en\u00fdmi technikami tv\u00e1\u0159en\u00ed keramiky. Po vytvarov\u00e1n\u00ed do po\u017eadovan\u00e9ho tvaru se SSIC slinuj\u00ed za vysok\u00e9 teploty a tlaku v atmosf\u00e9\u0159e inertn\u00edho plynu.<\/p>\n
Sp\u00e9k\u00e1n\u00ed lze rozd\u011blit na dv\u011b odli\u0161n\u00e9 f\u00e1ze, a to na sp\u00e9k\u00e1n\u00ed v pevn\u00e9 f\u00e1zi a v kapaln\u00e9 f\u00e1zi. Sp\u00e9k\u00e1n\u00ed v pevn\u00e9 f\u00e1zi vy\u017eaduje p\u0159\u00eddavek C a B jako pomocn\u00fdch l\u00e1tek pro sp\u00e9k\u00e1n\u00ed, aby se sn\u00ed\u017eila energie na hranic\u00edch zrn keramiky SiC, zat\u00edmco v kapaln\u00e9 f\u00e1zi se jako \u010dinidlo pou\u017e\u00edv\u00e1 jeden nebo v\u00edce eutektick\u00fdch oxid\u016f prvk\u016f (nap\u0159. Y2O3), kter\u00e9 vytv\u00e1\u0159ej\u00ed elektrolytickou f\u00e1zi s pohybem, difuz\u00ed a p\u0159enosem hmoty mezi \u010d\u00e1sticemi oxidu k\u0159emi\u010dit\u00e9ho, aby se zhustila hustota materi\u00e1lu.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide is an irreplaceable structural ceramic material due to its exceptional high temperature strength and oxidation resistance, making it […]<\/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-72","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\/72","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=72"}],"version-history":[{"count":1,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/posts\/72\/revisions"}],"predecessor-version":[{"id":73,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/posts\/72\/revisions\/73"}],"wp:attachment":[{"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/media?parent=72"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/categories?post=72"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/tags?post=72"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}