Reak\u010dn\u011b v\u00e1zan\u00fd karbid k\u0159em\u00edku (RBSC) je mimo\u0159\u00e1dn\u011b tvrd\u00fd a pevn\u00fd keramick\u00fd materi\u00e1l s vynikaj\u00edc\u00ed mechanickou pevnost\u00ed, odolnost\u00ed proti n\u00e1razu, chemickou stabilitou a tvarovatelnost\u00ed, d\u00edky \u010demu\u017e je vhodn\u00fd pro r\u016fzn\u00e9 aplikace.<\/p>\n
RB-SiC m\u00e1 ve srovn\u00e1n\u00ed se slinut\u00fdm karbidem k\u0159em\u00edku ni\u017e\u0161\u00ed tvrdost, ale jeho v\u00fdroba je jednodu\u0161\u0161\u00ed a levn\u011bj\u0161\u00ed, p\u0159i\u010dem\u017e se vyzna\u010duje vynikaj\u00edc\u00ed odolnost\u00ed proti tepeln\u00fdm \u0161ok\u016fm.<\/p>\n
Proces RMI vyu\u017e\u00edv\u00e1 \u010d\u00e1stice a-SiC zabudovan\u00e9 do por\u00e9zn\u00ed uhl\u00edkov\u00e9 p\u0159edlisku (G0) p\u0159ed infiltrac\u00ed kapaln\u00fdm k\u0159em\u00edkem, aby se dos\u00e1hlo reak\u010dn\u011b v\u00e1zan\u00e9ho karbidu k\u0159em\u00edku. Kapaln\u00fd k\u0159em\u00edk v\u0161ak bohu\u017eel m\u016f\u017ee zp\u016fsobit ucp\u00e1n\u00ed p\u00f3r\u016f v d\u016fsledku procesu infiltrace, a proto byl v t\u00e9to studii pou\u017eit v\u00edcef\u00e1zov\u00fd uhl\u00edk jako protil\u00e1tka proti tomuto probl\u00e9mu a ke zlep\u0161en\u00ed mechanick\u00fdch vlastnost\u00ed RB-SiC.<\/p>\n
V\u00edcef\u00e1zov\u00fd uhl\u00edk se skl\u00e1dal z jemn\u00fdch amorfn\u00edch saz\u00ed a hrub\u00e9ho mikrosf\u00e9rick\u00e9ho uhl\u00edku. P\u0159i infiltraci kapaln\u00fdm k\u0159em\u00edkem se mikrosf\u00e9rick\u00fd uhl\u00edk spot\u0159ebov\u00e1v\u00e1, zat\u00edmco amorfn\u00ed uhl\u00edk m\u016f\u017ee unikat z p\u00f3r\u016f, aby zabr\u00e1nil jejich ucp\u00e1n\u00ed reakcemi vypl\u0148uj\u00edc\u00edmi p\u00f3ry - p\u0159i pozorov\u00e1n\u00ed na vzorc\u00edch P10F90, P20F80 a P30F70 se tedy charakteristick\u00fd p\u00edk nevyskytoval, co\u017e nazna\u010duje, \u017ee v\u00edcef\u00e1zov\u00fd uhl\u00edk pomohl tomuto probl\u00e9mu p\u0159edej\u00edt a zlep\u0161it pevnost v ohybu s rostouc\u00ed teplotou infiltrace a dobou nam\u00e1\u010den\u00ed.<\/p>\n
Karbid k\u0159em\u00edku RB se vyr\u00e1b\u00ed infiltrac\u00ed roztaven\u00e9ho k\u0159em\u00edku do por\u00e9zn\u00ed uhl\u00edkov\u00e9 nebo grafitov\u00e9 p\u0159edlisku, kde reaguje s uhl\u00edkem za vzniku SiC a vytv\u00e1\u0159\u00ed vynikaj\u00edc\u00ed keramick\u00fd materi\u00e1l odoln\u00fd proti opot\u0159eben\u00ed, n\u00e1raz\u016fm a chemik\u00e1li\u00edm, kter\u00fd se dod\u00e1v\u00e1 v r\u016fzn\u00fdch tvarech a velikostech od jednoduch\u00fdch ku\u017eel\u016f a n\u00e1trubk\u016f a\u017e po v\u011bt\u0161\u00ed konstruk\u010dn\u00ed d\u00edly pro t\u011b\u017eebn\u00ed nebo zpracovatelsk\u00fd pr\u016fmysl.<\/p>\n
Slo\u017een\u00ed kompozitn\u00edho prekurzoru, zejm\u00e9na pom\u011br PF a FA, ovliv\u0148uje rychlost reakce mezi uhl\u00edkem a kapaln\u00fdm k\u0159em\u00edkem b\u011bhem vysokoteplotn\u00ed pyrol\u00fdzy. V\u00edcef\u00e1zov\u00fd uhl\u00edk zvy\u0161uje pr\u016fnik kapaln\u00e9ho k\u0159em\u00edku p\u00f3ry v por\u00e9zn\u00edch p\u0159edloh\u00e1ch; odstup\u0148ovan\u00e9 zdroje uhl\u00edku pom\u00e1haj\u00ed \u0159\u00eddit obsah b-SiC i voln\u00e9ho Si.<\/p>\n
Pevnost v ohybu a modul pru\u017enosti karbidu k\u0159em\u00edku RB lze podstatn\u011b zv\u00fd\u0161it pe\u010dliv\u00fdm t\u0159\u00edd\u011bn\u00edm jeho zdroje uhl\u00edku, a to d\u00edky eliminaci hladk\u00fdch \u010dern\u00fdch a b\u00edl\u00fdch blokov\u00fdch povrch\u016f zrn, kter\u00e9 zp\u016fsobuj\u00ed mezikrystalov\u00e9 lomy p\u0159i ohybu.<\/p>\n
Tepeln\u00e9 vlastnosti reak\u010dn\u011b v\u00e1zan\u00e9 keramiky z karbidu k\u0159em\u00edku z\u00e1vis\u00ed na typu a pod\u00edlu vazby. Reak\u010dn\u011b v\u00e1zan\u00fd karbid k\u0159em\u00edku (RBSC), infiltrovan\u00fd kovov\u00fdmi \u010d\u00e1sticemi k\u0159em\u00edku, infiltrovan\u00fd do uhl\u00edkov\u00fdch nebo grafitov\u00fdch preforem, kter\u00e9 se b\u011bhem tohoto procesu nesmr\u0161\u0165uj\u00ed; lze tak vytv\u00e1\u0159et d\u00edly s velmi p\u0159esn\u00fdmi rozm\u011bry.<\/p>\n
Po infiltraci RBSC se pak podrob\u00ed vysokoteplotn\u00edmu nitridov\u00e1n\u00ed p\u0159i vysok\u00fdch teplot\u00e1ch. T\u00edm se kovov\u00fd k\u0159em\u00edk p\u0159em\u011bn\u00ed na nitrid SiC a zb\u00fdvaj\u00edc\u00ed p\u00f3rov\u00e9 prostory se vypln\u00ed s\u00ed\u0165ov\u00fdm materi\u00e1lem karbidu k\u0159em\u00edku. XRD ukazuje, \u017ee tato forma obsahuje diamant, a-SiC, b-SiC, Si a SiO2, zat\u00edmco SEM ukazuje vrstvy grafitu i amorfn\u00ed uhl\u00edk.<\/p>\n
D\u00edky p\u0159\u00edtomn\u00e9 grafitov\u00e9 vrstv\u011b vykazuje RBSC ni\u017e\u0161\u00ed hodnoty k ne\u017e slinut\u00fd SiC, p\u0159esto v\u0161ak p\u0159ed\u010d\u00ed hodnoty NSIC. Krom\u011b toho v\u00fdrazn\u011b p\u0159ekon\u00e1v\u00e1 keramiku na b\u00e1zi SiO2, pokud jde o odolnost proti korozi, odolnost proti vysok\u00fdm teplot\u00e1m, odolnost proti tepeln\u00fdm \u0161ok\u016fm a schopnost absorbovat tepeln\u00e9 \u0161oky.<\/p>\n
Reak\u010dn\u011b v\u00e1zan\u00fd karbid k\u0159em\u00edku m\u00e1 skv\u011bl\u00e9 elektrick\u00e9 vlastnosti, jako je n\u00edzk\u00fd m\u011brn\u00fd odpor a vysok\u00e1 tepeln\u00e1 vodivost. D\u00edky t\u011bmto vlastnostem je vynikaj\u00edc\u00ed volbou materi\u00e1lu pro elektrick\u00e9 topn\u00e9 prvky. Krom\u011b toho je d\u00edky sv\u00e9 chemick\u00e9 inertnosti a odolnosti v\u016f\u010di oxidaci vhodn\u00fd pro termo\u010dl\u00e1nky pec\u00ed, hroty ho\u0159\u00e1k\u016f, kontroln\u00ed cihly a mufny v pec\u00edch; d\u00edky sv\u00e9 vynikaj\u00edc\u00ed odolnosti v\u016f\u010di tepeln\u00fdm \u0161ok\u016fm je vhodn\u00fd tak\u00e9 jako n\u00e1bytek v pec\u00edch.<\/p>\n
Reak\u010dn\u011b v\u00e1zan\u00fd SiC lze vytvo\u0159it procesem sm\u00edch\u00e1n\u00ed jemn\u011b rozd\u011blen\u00fdch intimn\u00edch sm\u011bs\u00ed siku a uhl\u00edku s plastifik\u00e1torem, n\u00e1sledn\u00fdm tvarov\u00e1n\u00edm a vyp\u00e1len\u00edm plastifik\u00e1toru p\u0159ed infiltrac\u00ed kapaln\u00fdm nebo plynn\u00fdm k\u0159em\u00edkem. Tato reakce umo\u017e\u0148uje k\u0159em\u00edku v\u00e1zat se s uhl\u00edkem za vzniku v\u011bt\u0161\u00edho mno\u017estv\u00ed karbidu k\u0159em\u00edku, kter\u00fd pak reaguje s p\u016fvodn\u00edm karbidem k\u0159em\u00edku za vzniku kompozitu sest\u00e1vaj\u00edc\u00edho z a-SiC, b-SiC a zbytkov\u00e9ho Si.<\/p>\n
V dob\u011b infiltrace se tvrd\u00ed, \u017ee granule a-SiC a b-SiC vytvo\u0159en\u00e9 b\u011bhem reakce jsou rovnom\u011brn\u011b rozpt\u00fdleny po cel\u00e9 por\u00e9zn\u00ed p\u0159edloze bez hrudkov\u00e1n\u00ed, co\u017e je pravd\u011bpodobn\u011b zp\u016fsobeno t\u00edm, \u017ee kapil\u00e1rn\u00ed kan\u00e1ly nejsou blokov\u00e1ny nov\u011b vytvo\u0159en\u00fdmi \u010d\u00e1sticemi b-SiC.<\/p>","protected":false},"excerpt":{"rendered":"
Reaction bonded silicon carbide (RBSC) is an exceptionally hard and strong ceramic material with superior mechanical strength, impact resistance, chemical […]<\/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-36","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\/36","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=36"}],"version-history":[{"count":1,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/posts\/36\/revisions"}],"predecessor-version":[{"id":37,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/posts\/36\/revisions\/37"}],"wp:attachment":[{"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/media?parent=36"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/categories?post=36"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/cs\/wp-json\/wp\/v2\/tags?post=36"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}