Karbid k\u0159em\u00edku je jedn\u00edm z nej\u017e\u00e1dan\u011bj\u0161\u00edch keramick\u00fdch materi\u00e1l\u016f, kter\u00fd nab\u00edz\u00ed vynikaj\u00edc\u00ed vlastnosti, jako je tvrdost, pevnost, tepeln\u00e1 odolnost a odolnost proti korozi\/oxidaci.<\/p>\n
Reak\u010dn\u00ed sp\u00e9k\u00e1n\u00ed je nejlep\u0161\u00edm \u0159e\u0161en\u00edm pro v\u00fdrobu velk\u00fdch, tvarov\u011b slo\u017eit\u00fdch keramick\u00fdch v\u00fdrobk\u016f z karbidu k\u0159em\u00edku ve velk\u00e9m m\u011b\u0159\u00edtku. Bohu\u017eel je v\u0161ak jej\u00ed \u00fa\u010dinnost spojena s n\u011bkter\u00fdmi nev\u00fdhodami, jako je nerovnom\u011brn\u00e9 rozlo\u017een\u00ed hustoty a prask\u00e1n\u00ed sp\u00e9kan\u00fdch v\u00fdrobk\u016f.<\/p>\n
Karbid k\u0159em\u00edku (SiC) je jedn\u00edm z nejtvrd\u0161\u00edch keramick\u00fdch materi\u00e1l\u016f, kter\u00fd nab\u00edz\u00ed v\u00fdjime\u010dnou pevnost p\u0159i vysok\u00fdch teplot\u00e1ch a je vhodn\u00fd pro celou \u0159adu aplikac\u00ed, jako jsou sou\u010d\u00e1sti t\u011bsn\u011bn\u00ed s tvrd\u00fdm povrchem, sou\u010d\u00e1sti za\u0159\u00edzen\u00ed pro v\u00fdrobu polovodi\u010d\u016f a konstruk\u010dn\u00ed sou\u010d\u00e1sti jadern\u00fdch f\u00fazn\u00edch reaktor\u016f. Krom\u011b toho se SiC vyzna\u010duje vynikaj\u00edc\u00ed odolnost\u00ed proti chemik\u00e1li\u00edm a opot\u0159eben\u00ed.<\/p>\n
Reak\u010dn\u00ed a beztlakov\u00e9 slinov\u00e1n\u00ed jsou dv\u011b z\u00e1kladn\u00ed metody v\u00fdroby SiC. Reak\u010dn\u00ed slinov\u00e1n\u00ed nab\u00edz\u00ed ni\u017e\u0161\u00ed teploty zpracov\u00e1n\u00ed, ale trp\u00ed n\u00edzkou pevnost\u00ed v ohybu a odolnost\u00ed v\u016f\u010di chemik\u00e1li\u00edm, jako jsou siln\u00e9 kyseliny a z\u00e1sady; oproti tomu beztlakov\u00e9 slinov\u00e1n\u00ed nab\u00edz\u00ed lep\u0161\u00ed flexibilitu, vysokou hustotu slinov\u00e1n\u00ed a dobrou tvarovou st\u00e1lost, ale za cenu vy\u0161\u0161\u00edch n\u00e1klad\u016f na zpracov\u00e1n\u00ed kv\u016fli p\u0159\u00eddavk\u016fm kov\u016f, jako je hlin\u00edk, b\u00f3r a uhl\u00edk.<\/p>\n
Slinut\u00fd karbid k\u0159em\u00edku vynik\u00e1 mezi sv\u00fdmi kolegy mimo\u0159\u00e1dnou tvrdost\u00ed. S Vickersovou tvrdost\u00ed 2563 HV, kter\u00e1 v\u00fdrazn\u011b p\u0159evy\u0161uje po\u017eadavky na panc\u00ed\u0159 1500 HV, je slinut\u00fd karbid k\u0159em\u00edku tak\u00e9 mimo\u0159\u00e1dn\u011b hou\u017eevnat\u00fd materi\u00e1l a vykazuje prask\u00e1n\u00ed medi\u00e1nov\u00e9ho typu, tak\u017ee je vhodn\u00fd pro aplikace s v\u00edce \u00fadery.<\/p>\n
Sp\u00e9k\u00e1n\u00ed hraje z\u00e1sadn\u00ed roli p\u0159i v\u00fdrob\u011b kvalitn\u00edch slinut\u00fdch v\u00fdrobk\u016f z karbidu k\u0159em\u00edku. T\u0159\u00eddy s reak\u010dn\u00edm lepen\u00edm nab\u00edzej\u00ed hrub\u00e1 zrna s ni\u017e\u0161\u00ed tvrdost\u00ed a teplotou pou\u017eit\u00ed; t\u0159\u00eddy s p\u0159\u00edm\u00fdm sp\u00e9k\u00e1n\u00edm nab\u00edzej\u00ed jemn\u011bj\u0161\u00ed \u010d\u00e1stice pro lep\u0161\u00ed odolnost proti trhlin\u00e1m a teplotu pou\u017eit\u00ed, tak\u017ee jsou lep\u0161\u00ed volbou ne\u017e t\u0159\u00eddy s reak\u010dn\u00edm lepen\u00edm, pokud jde o t\u011bsnic\u00ed plochy a vysoce v\u00fdkonn\u00e9 t\u011bsnic\u00ed plochy.<\/p>\n
Slinut\u00fd karbid k\u0159em\u00edku se osv\u011bd\u010dil jako odoln\u00fd proti korozi v kysel\u00e9m prost\u0159ed\u00ed d\u00edky sv\u00e9 vynikaj\u00edc\u00ed oxida\u010dn\u00ed odolnosti, kdy kolem sv\u00e9ho materi\u00e1lu vytv\u00e1\u0159\u00ed kysl\u00edkovou bari\u00e9ru, kter\u00e1 jej chr\u00e1n\u00ed p\u0159ed napaden\u00edm kysel\u00fdmi chemik\u00e1liemi a z\u00e1rove\u0148 zaji\u0161\u0165uje dal\u0161\u00ed chemickou degradaci z jin\u00fdch agresivn\u00edch prost\u0159ed\u00ed.<\/p>\n
Odolnost karbidu k\u0159em\u00edku proti korozi z\u00e1vis\u00ed do zna\u010dn\u00e9 m\u00edry na faktorech, jako jsou ne\u010distoty, pomocn\u00e9 l\u00e1tky p\u0159i sp\u00e9k\u00e1n\u00ed, f\u00e1ze na hranic\u00edch zrn, p\u00f3rovitost a bezprost\u0159edn\u00ed reak\u010dn\u00ed historie materi\u00e1lu. Tyto vlastnosti mohou zm\u011bnit jeho dominantn\u00ed reak\u010dn\u00ed sekvenci za provozn\u00edch podm\u00ednek, a t\u00edm ovlivnit jeho n\u00e1sledn\u00e9 korozn\u00ed chov\u00e1n\u00ed.<\/p>\n
Beztlakov\u011b slinut\u00fd karbid k\u0159em\u00edku obvykle p\u0159ed\u010d\u00ed reaktivn\u011b pojen\u00fd karbid k\u0159em\u00edku, pokud jde o odolnost v\u016f\u010di vysok\u00fdm teplot\u00e1m a mechanickou tvrdost, ale r\u016fzn\u00e9 aplikace vy\u017eaduj\u00ed r\u016fzn\u00e9 vlastnosti materi\u00e1l\u016f; proto v\u00fdb\u011br mezi slinut\u00fdm a reaktivn\u011b pojen\u00fdm z\u00e1vis\u00ed na va\u0161ich konkr\u00e9tn\u00edch po\u017eadavc\u00edch.<\/p>\n
Obr\u00e1b\u011bn\u00ed slinut\u00e9ho karbidu k\u0159em\u00edku (SSiC) m\u016f\u017ee b\u00fdt obt\u00ed\u017en\u00e9 a n\u00e1kladn\u00e9 kv\u016fli jeho extr\u00e9mn\u00ed tvrdosti. Spole\u010dnost GAB Neumann pou\u017e\u00edv\u00e1 beztlakov\u00e9 monolitick\u00e9 d\u00edly ze slinut\u00e9ho karbidu k\u0159em\u00edku vyr\u00e1b\u011bn\u00e9 intenzivn\u00edm v\u00fdrobn\u00edm procesem, kter\u00fd zahrnuje p\u0159\u00edpravu pr\u00e1\u0161ku, m\u00edch\u00e1n\u00ed s pojivem, tvarov\u00e1n\u00ed, izostatick\u00e9 lisov\u00e1n\u00ed za studena a nakonec slinov\u00e1n\u00ed p\u0159i vysok\u00fdch teplot\u00e1ch a po slinut\u00ed obr\u00e1b\u011bn\u00ed s p\u0159esn\u00fdmi tolerancemi pomoc\u00ed n\u00e1stroj\u016f s diamantov\u00fdm povlakem.<\/p>\n
Karbid k\u0159em\u00edku si zachov\u00e1v\u00e1 tvrdost a pevnost i p\u0159i velmi vysok\u00fdch teplot\u00e1ch, tak\u017ee je vysoce odoln\u00fd v\u016f\u010di opot\u0159eben\u00ed, korozi a tepeln\u00fdm \u0161ok\u016fm. Nav\u00edc jeho odolnost proti oxidaci pat\u0159\u00ed k nejvy\u0161\u0161\u00edm mezi neoxidov\u00fdmi keramick\u00fdmi materi\u00e1ly a v\u00e1\u017e\u00ed o polovinu m\u00e9n\u011b ne\u017e ocel.<\/p>\n
Reak\u010dn\u011b v\u00e1zan\u00e9 a p\u0159\u00edmo slinut\u00e9 v\u00fdrobn\u00ed procesy pro v\u00fdrobu karbidu k\u0159em\u00edku jsou dv\u011b \u0161iroce pou\u017e\u00edvan\u00e9 techniky pro jeho v\u00fdrobu. Ka\u017ed\u00e1 metoda tv\u00e1\u0159en\u00ed hraje ned\u00edlnou roli p\u0159i utv\u00e1\u0159en\u00ed kone\u010dn\u00e9 mikrostruktury a vlastnost\u00ed vyr\u00e1b\u011bn\u00e9ho keramick\u00e9ho materi\u00e1lu.<\/p>\n
Reak\u010dn\u011b v\u00e1zan\u00fd karbid k\u0159em\u00edku lze vyrobit infiltrac\u00ed kompakt\u016f slo\u017een\u00fdch ze sm\u011bsi pr\u00e1\u0161ku a-SiC a uhl\u00edku kapaln\u00fdm k\u0159em\u00edkem, pot\u00e9 reakc\u00ed tohoto nov\u00e9ho SiC se st\u00e1vaj\u00edc\u00edmi \u010d\u00e1sticemi za vzniku hust\u00fdch zhu\u0161t\u011bn\u00fdch t\u011bles SiC, kter\u00e1 maj\u00ed \u00faplnou hustotu.<\/p>\n
Mikrostruktura a-SiC s p\u0159idru\u017eenou krystalickou strukturou a-SiC -b-SiC poskytuje vynikaj\u00edc\u00ed odolnost proti opot\u0159eben\u00ed a tepeln\u00fdm \u0161ok\u016fm, ale elektrick\u00fd odpor je ni\u017e\u0161\u00ed v d\u016fsledku p\u0159\u00edtomnosti zrn a-SiC i b-SiC v t\u00e9to form\u011b karbidu k\u0159em\u00edku.<\/p>\n
Reak\u010dn\u00ed slinov\u00e1n\u00ed je \u00fa\u010dinn\u00e1 a ekonomick\u00e1 metoda vytv\u00e1\u0159en\u00ed extr\u00e9mn\u011b hou\u017eevnat\u00e9 keramiky z karbidu k\u0159em\u00edku s vynikaj\u00edc\u00ed hou\u017eevnatost\u00ed, d\u00edky \u010demu\u017e je tato metoda vhodn\u00e1 pro p\u0159\u00edpravu velk\u00fdch rozm\u011br\u016f nebo slo\u017eit\u00fdch tvar\u016f. N\u00edzk\u00e9 teploty sp\u00e9k\u00e1n\u00ed zaji\u0161\u0165uj\u00ed rychl\u00e9 \u010dasy sp\u00e9k\u00e1n\u00ed, kdy se b\u011bhem n\u011bkolika minut vytvo\u0159\u00ed d\u00edly s t\u00e9m\u011b\u0159 \u010distou velikost\u00ed; mezi jej\u00ed jedin\u00e9 nev\u00fdhody pat\u0159\u00ed vysok\u00e9 n\u00e1roky na materi\u00e1l, n\u00e1klady na spot\u0159ebu energie a drah\u00e9 vybaven\u00ed.<\/p>\n
Karbid k\u0159em\u00edku je jedn\u00edm z nejtvrd\u0161\u00edch a nejodoln\u011bj\u0161\u00edch keramick\u00fdch materi\u00e1l\u016f na trhu. Zachov\u00e1v\u00e1 si svou tvrdost a pevnost i p\u0159i extr\u00e9mn\u011b vysok\u00fdch teplot\u00e1ch, co\u017e p\u0159isp\u00edv\u00e1 k jeho mimo\u0159\u00e1dn\u00e9 odolnosti proti opot\u0159eben\u00ed. Krom\u011b toho se tato keramika m\u016f\u017ee pochlubit odolnost\u00ed proti tepeln\u00fdm \u0161ok\u016fm a odolnost\u00ed proti korozi a oxidaci; je o polovinu t\u011b\u017e\u0161\u00ed ne\u017e ocel, a p\u0159esto odol\u00e1v\u00e1 extr\u00e9mn\u00edm tlak\u016fm a teplotn\u00edm zm\u011bn\u00e1m.<\/p>\n
Tepeln\u00e1 vodivost SSiC do zna\u010dn\u00e9 m\u00edry z\u00e1vis\u00ed na zvolen\u00e9m procesu sp\u00e9k\u00e1n\u00ed; beztlakov\u00e9 sp\u00e9k\u00e1n\u00ed nebo sp\u00e9k\u00e1n\u00ed reak\u010dn\u00ed vazbou vytv\u00e1\u0159ej\u00ed r\u016fzn\u00e9 mikrostruktury, kter\u00e9 ovliv\u0148uj\u00ed jeho tepeln\u011b vodiv\u00e9 vlastnosti.<\/p>\n
Reak\u010dn\u011b v\u00e1zan\u00fd SiC se vytv\u00e1\u0159\u00ed infiltrac\u00ed por\u00e9zn\u00edch uhl\u00edkov\u00fdch nebo grafitov\u00fdch preforem kapaln\u00fdm k\u0159em\u00edkem, kter\u00fd reaguje s uhl\u00edkem a vytv\u00e1\u0159\u00ed ztuhlou keramiku SiC, kterou lze n\u00e1sledn\u011b lisovat do tvar\u016f. Reak\u010dn\u011b v\u00e1zan\u00e1 keramika b\u00fdv\u00e1 m\u011bk\u010d\u00ed a m\u00e9n\u011b hust\u00e1 ne\u017e jej\u00ed prot\u011bj\u0161ky z SSiC, ale nab\u00edz\u00ed dobrou odolnost proti opot\u0159eben\u00ed p\u0159i vy\u0161\u0161\u00edch teplot\u00e1ch a z\u00e1rove\u0148 vysokou odolnost proti oxidaci a korozi.<\/p>\n
Oxidy vz\u00e1cn\u00fdch zemin mohou b\u00fdt zavedeny jako p\u0159\u00edsady pro zlep\u0161en\u00ed slinov\u00e1n\u00ed b-SiC, av\u0161ak jejich velk\u00fd iontov\u00fd polom\u011br jim br\u00e1n\u00ed proniknout do jeho krystalov\u00e9 m\u0159\u00ed\u017eky a zachycuj\u00ed se mezi zrny - proto je rozhoduj\u00edc\u00ed v\u00fdb\u011br p\u0159\u00edsad, kter\u00e9 do n\u00ed mohou proniknout - hlin\u00edk, b\u00f3r a uhl\u00edk (ABC) je jednou z takov\u00fdch slibn\u00fdch p\u0159\u00edsad, kter\u00e9 mohou b\u00fdt p\u0159id\u00e1ny v\u00e1zan\u00e9 na zrna pro aplikace slinov\u00e1n\u00ed p\u0159i ni\u017e\u0161\u00edch teplot\u00e1ch zpracov\u00e1n\u00ed.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide is one of the most desirable ceramic materials, offering outstanding properties such as hardness, strength, heat resistance and corrosion\/oxidation resistance. Reaction sintering is the best solution for producing large, complex shape silicon carbide ceramics at scale. Unfortunately, however, its efficiency comes with some drawbacks such as uneven density distribution and cracking sintered products. […]<\/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-104","post","type-post","status-publish","format-standard","hentry","category-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/posts\/104","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=104"}],"version-history":[{"count":1,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/posts\/104\/revisions"}],"predecessor-version":[{"id":105,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/posts\/104\/revisions\/105"}],"wp:attachment":[{"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/media?parent=104"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/categories?post=104"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/cs\/wp-json\/wp\/v2\/tags?post=104"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}