Karbid krem\u00edka je nenahradite\u013en\u00fd kon\u0161truk\u010dn\u00fd keramick\u00fd materi\u00e1l v\u010faka svojej v\u00fdnimo\u010dnej pevnosti pri vysok\u00fdch teplot\u00e1ch a odolnosti vo\u010di oxid\u00e1cii, v\u010faka \u010domu je nenahradite\u013en\u00fd v oblasti stroj\u00e1rskej v\u00fdroby, leteckej techniky a informa\u010dnej elektroniky.<\/p>\n
Reak\u010dn\u00e9 spekanie pon\u00faka n\u00edzke teploty a kr\u00e1tke \u010dasy spekania pri v\u00fdrobe tvarov bl\u00edzkych \u010distej ve\u013ekosti, ale je obmedzen\u00e9 nerovnomern\u00fdm rozlo\u017een\u00edm hustoty, praskan\u00edm spekan\u00fdch v\u00fdrobkov a nedostato\u010dnou penetr\u00e1ciou krem\u00edka po\u010das procesov spekania.<\/p>\n
Karbid krem\u00edka je extr\u00e9mne tvrd\u00fd a h\u00fa\u017eevnat\u00fd keramick\u00fd materi\u00e1l zn\u00e1my svojou vynikaj\u00facou pevnos\u0165ou pri vysok\u00fdch teplot\u00e1ch, odolnos\u0165ou proti opotrebovaniu a chemickej oxid\u00e1cii. V\u010faka t\u00fdmto vlastnostiam sa karbid krem\u00edka pou\u017e\u00edva v mnoh\u00fdch priemyseln\u00fdch aplik\u00e1ci\u00e1ch vr\u00e1tane jadrov\u00fdch elektr\u00e1rn\u00ed, pec\u00ed, pr\u00fadov\u00fdch motorov, raketov\u00fdch d\u00fdz a v\u00fdroby papiera.<\/p>\n
Jedn\u00fdm zo sp\u00f4sobov zlep\u0161enia mechanick\u00fdch vlastnost\u00ed spekan\u00e9ho karbidu krem\u00edka pri vysok\u00fdch teplot\u00e1ch je pridanie pr\u00edsad, ako je hlin\u00edk, b\u00f3r a uhl\u00edk (SiC-ABC), ktor\u00e9 zvy\u0161uj\u00fa odolnos\u0165 proti te\u010deniu. Tieto pr\u00edsady menia energie na hraniciach z\u0155n a povrchov\u00e9 energie, pri\u010dom zvy\u0161uj\u00fa objemov\u00fa dif\u00faziu a odr\u00e1dzaj\u00fa od tvorby skla na hraniciach z\u0155n.<\/p>\n
\u010eal\u0161\u00edm sp\u00f4sobom, ako zv\u00fd\u0161i\u0165 mechanick\u00e9 vlastnosti, je beztlakov\u00e9 spekanie, ktor\u00e9 zah\u0155\u0148a spekanie SiC pr\u00e1\u0161ku bez pou\u017eitia vonkaj\u0161ieho tlaku. V\u00fdhoda tejto met\u00f3dy spo\u010d\u00edva v elimin\u00e1cii odch\u00fdlok hustoty sp\u00f4soben\u00fdch tradi\u010dn\u00fdmi met\u00f3dami spekania lisovan\u00edm za tepla, ktor\u00e9 maj\u00fa za n\u00e1sledok v\u00fdrazn\u00e9 rozmerov\u00e9 zmeny a zn\u00ed\u017een\u00fa kvalitu v\u00fdrobku - z\u00e1rove\u0148 sa pri nej dosahuj\u00fa hustoty bli\u017e\u0161ie k teoretick\u00fdm hodnot\u00e1m ako kedyko\u013evek predt\u00fdm.<\/p>\n
Karbid krem\u00edka vykazuje vynikaj\u00facu odolnos\u0165 vo\u010di chemickej kor\u00f3zii v \u0161irokom rozsahu prostred\u00ed a\u017e do 1700 stup\u0148ov C, ako je such\u00fd kysl\u00edk, hor\u00face plynn\u00e9 pary a kvapaln\u00e9 soli a kovy, ako aj roztaven\u00e9 soli a trosky uho\u013en\u00e9ho popola.<\/p>\n
Spekan\u00fd karbid krem\u00edka m\u00e1 v\u010faka svojej \u0161trukt\u00fare a kvalite povrchu vynikaj\u00facu odolnos\u0165 proti kor\u00f3zii. Tento materi\u00e1l sa m\u00f4\u017ee pochv\u00e1li\u0165 silnou odolnos\u0165ou proti er\u00f3zii (k\u013azaniu), mechanickej pevnosti, tepeln\u00fdm \u0161okom a opotrebovaniu.<\/p>\n
Vysokoteplotn\u00fd spekan\u00fd materi\u00e1l z karbidu krem\u00edka XICAR (be\u017ene ozna\u010dovan\u00fd ako alternat\u00edva Hexoloy SE) sa uk\u00e1zal ako vysoko odoln\u00fd vo\u010di chemickej kor\u00f3zii v kysl\u00fdch prostrediach, ako s\u00fa koncentrovan\u00e1 HCl a HNO3, pri\u010dom vzorky o\u0161etren\u00e9 Y2O3 maj\u00fa vy\u0161\u0161iu odolnos\u0165 ako vzorky, pri ktor\u00fdch sa pou\u017eila pomocn\u00e1 l\u00e1tka MgO.<\/p>\n
Reak\u010dne viazan\u00fd spekan\u00fd karbid krem\u00edka, be\u017ene ozna\u010dovan\u00fd ako samoviazan\u00fd karbid krem\u00edka, sa vyr\u00e1ba reakciou por\u00e9zneho keramick\u00e9ho telesa obsahuj\u00faceho uhl\u00edk s tekut\u00fdm krem\u00edkom. T\u00e1to zmes prenik\u00e1 do keramick\u00e9ho telesa, reaguje s grafitom za vzniku b-SiC a potom sa sp\u00e1ja s existuj\u00facimi \u010dasticami a-SiC, aby sa vytvoril reak\u010dne spekan\u00fd karbid krem\u00edka s plnou hustotou a r\u00f4znymi tvarmi, ktor\u00e9 s\u00fa t\u00fdmto procesom dostupn\u00e9.<\/p>\n
Karbid krem\u00edka je jedn\u00fdm z najpevnej\u0161\u00edch keramick\u00fdch materi\u00e1lov. Karbid krem\u00edka sa vyzna\u010duje vynikaj\u00facou pevnos\u0165ou pri vysok\u00fdch teplot\u00e1ch a odolnos\u0165ou vo\u010di oxid\u00e1cii, preto je vynikaj\u00facou vo\u013ebou materi\u00e1lu na pou\u017eitie v mnoh\u00fdch priemyseln\u00fdch aplik\u00e1ci\u00e1ch.<\/p>\n
Keramiku z karbidu krem\u00edka mo\u017eno zvy\u010dajne vyr\u00e1ba\u0165 bu\u010f beztlakov\u00fdm spekan\u00edm, alebo reak\u010dn\u00fdm sp\u00e1jan\u00edm a spolo\u010dnos\u0165 Saint-Gobain Performance Ceramics & Refractories pon\u00faka oba typy, ktor\u00e9 vyhovuj\u00fa r\u00f4znym kone\u010dn\u00fdm aplik\u00e1ci\u00e1m.<\/p>\n
Beztlakov\u00fd spekan\u00fd karbid krem\u00edka sa vyr\u00e1ba kombin\u00e1ciou jemn\u00fdch \u010dast\u00edc SiC pr\u00e1\u0161ku s neoxidov\u00fdmi spekan\u00fdmi pomocn\u00fdmi l\u00e1tkami a spekan\u00edm pri teplot\u00e1ch vy\u0161\u0161\u00edch ako 2000 \u00b0C v inertnej atmosf\u00e9re, \u010d\u00edm sa z\u00edskava materi\u00e1l s vysokou hustotou, vynikaj\u00facou odolnos\u0165ou proti oxid\u00e1cii, kor\u00f3zii a mechanick\u00fdmi vlastnos\u0165ami.<\/p>\n
Reak\u010dn\u00e9 spekanie je nov\u00fdm procesom v\u00fdroby keramiky z karbidu krem\u00edka (SiC), ktor\u00fd pon\u00faka v\u00fdhody, ako s\u00fa hust\u00e9 \u0161trukt\u00fary, ni\u017e\u0161ie teploty spracovania, tvarov\u00e9 mo\u017enosti, n\u00edzke n\u00e1klady a vy\u0161\u0161ia \u010distota. Nane\u0161\u0165astie v\u0161ak jeho pevnos\u0165 v ohybe nedosahuje pevnos\u0165 \u0161tandardn\u00e9ho spekan\u00e9ho SiC v d\u00f4sledku ve\u013ekosti zvy\u0161kov\u00e9ho uhl\u00edka (Si) v jeho mikro\u0161trukt\u00fare.<\/p>\n
Keramika zo spekan\u00e9ho karbidu krem\u00edka patr\u00ed medzi najtvrd\u0161ie a najpevnej\u0161ie keramick\u00e9 materi\u00e1ly, pri\u010dom si zachov\u00e1va pevnos\u0165 aj pri extr\u00e9mne vysok\u00fdch teplot\u00e1ch - je teda vynikaj\u00facou vo\u013ebou pre aplik\u00e1cie, kde je k\u013e\u00fa\u010dov\u00e1 odolnos\u0165 vo\u010di vysok\u00fdm teplot\u00e1m.<\/p>\n
SSIC vykazuje takmer kon\u0161tantn\u00fa pevnos\u0165 v \u0161irokom rozsahu tepl\u00f4t a zachov\u00e1va si svoju h\u00fa\u017eevnatos\u0165 aj pri vysokom tlaku, v\u010faka \u010domu je ve\u013emi ob\u013e\u00fabenou vo\u013ebou materi\u00e1lu pre vysoko v\u00fdkonn\u00e9 komponenty \u010derpadiel a in\u00e9 d\u00f4le\u017eit\u00e9 \u010dasti zariaden\u00ed.<\/p>\n
SSIC sa vyr\u00e1baj\u00fa be\u017en\u00fdmi technikami tvarovania keramiky. Po vytvarovan\u00ed do po\u017eadovan\u00e9ho tvaru sa SSIC spek\u00e1 pri vysokej teplote a tlaku v atmosf\u00e9re inertn\u00e9ho plynu.<\/p>\n
Spekanie mo\u017eno rozdeli\u0165 na dve odli\u0161n\u00e9 f\u00e1zy, spekanie v tuhej f\u00e1ze a spekanie v kvapalnej f\u00e1ze. Spekanie v pevnej f\u00e1ze si vy\u017eaduje prid\u00e1vanie C a B ako spekalcov na zn\u00ed\u017eenie energie na hranici z\u0155n keramiky SiC, zatia\u013e \u010do kvapaln\u00e1 f\u00e1za vyu\u017e\u00edva ako \u010dinidlo jeden alebo viac eutektick\u00fdch oxidov prvkov (ako napr\u00edklad Y2O3), \u010d\u00edm sa vytv\u00e1ra elektrolytick\u00e1 f\u00e1za s pohybom, dif\u00faziou a prenosom hmoty medzi \u010dasticami oxidu kremi\u010dit\u00e9ho na zhutnenie hustoty 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\/sk\/wp-json\/wp\/v2\/posts\/72","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=72"}],"version-history":[{"count":1,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/posts\/72\/revisions"}],"predecessor-version":[{"id":73,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/posts\/72\/revisions\/73"}],"wp:attachment":[{"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/media?parent=72"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/categories?post=72"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/sk\/wp-json\/wp\/v2\/tags?post=72"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}