A szerkezeti ker\u00e1mi\u00e1k, m\u00e1s n\u00e9ven m\u0171szaki ker\u00e1mi\u00e1k a fejlett ker\u00e1mi\u00e1k egy olyan oszt\u00e1lya, amely els\u0151sorban az anyagok mechanikai, termikus, k\u00e9miai \u00e9s egy\u00e9b hat\u00e1sait fejti ki. A szerkezeti ker\u00e1mi\u00e1k tulajdons\u00e1gai a magas h\u0151m\u00e9rs\u00e9kleti ellen\u00e1ll\u00e1s, a kop\u00e1s\u00e1ll\u00f3s\u00e1g, a korr\u00f3zi\u00f3\u00e1ll\u00f3s\u00e1g, az oxid\u00e1ci\u00f3val szembeni ellen\u00e1ll\u00e1s \u00e9s a magas h\u0151m\u00e9rs\u00e9kleten val\u00f3 alacsony k\u00fasz\u00e1s. Ellen\u00e1llnak a kem\u00e9ny munkak\u00f6rnyezetnek, amelyre a f\u00e9manyagok \u00e9s a polimer anyagok nem alkalmasak. Sz\u00e9les k\u00f6rben haszn\u00e1lj\u00e1k \u0151ket a rep\u00fcl\u00e9sben, a g\u00e9piparban, az aut\u00f3iparban, a koh\u00e1szatban, a vegyiparban, az elektronik\u00e1ban \u00e9s m\u00e1s ter\u00fcleteken, \u00e9s a ker\u00e1miaanyagok nagyon gyorsan fejl\u0151d\u0151 oszt\u00e1ly\u00e1v\u00e1 v\u00e1ltak.A szerkezeti ker\u00e1mi\u00e1k k\u00f6z\u00e9 els\u0151sorban az oxidker\u00e1mi\u00e1k, a nitridker\u00e1mi\u00e1k \u00e9s a karbidker\u00e1mi\u00e1k tartoznak. A szil\u00edcium-karbid ker\u00e1mi\u00e1t els\u0151sorban az al\u00e1bbiakban mutatjuk be. A szil\u00edcium-karbid, k\u00f6zismert nev\u00e9n karborundum, m\u00e1s n\u00e9ven karborundum, egy tipikus kovalens k\u00f6t\u00e9s\u0171 vegy\u00fclet, amely szinte nem l\u00e9tezik a term\u00e9szetben. 1890-ben, amikor Eword \u00e9s G. Acheson gy\u00e9m\u00e1ntot akartak szintetiz\u00e1lni \u00fagy, hogy kataliz\u00e1tork\u00e9nt szil\u00edciumot adtak a sz\u00e9nhez, szil\u00edciumkarbidot \u00e1ll\u00edtottak el\u0151. Ma is tanulm\u00e1nyozz\u00e1k \u00e9s fejlesztik.<\/p>\n
A szil\u00edcium-karbidot kezdetben szuperkem\u00e9ny teljes\u00edtm\u00e9nye miatt haszn\u00e1lt\u00e1k, amelyet k\u00fcl\u00f6nb\u00f6z\u0151 csiszol\u00f3korongokk\u00e1, csiszol\u00f3sz\u00f6vetekk\u00e9, csiszol\u00f3pap\u00edrr\u00e1 \u00e9s k\u00fcl\u00f6nb\u00f6z\u0151 csiszol\u00f3anyagokk\u00e1 lehet el\u0151\u00e1ll\u00edtani, \u00e9s sz\u00e9les k\u00f6rben haszn\u00e1lj\u00e1k a mechanikai feldolgoz\u00f3iparban. A m\u00e1sodik vil\u00e1gh\u00e1bor\u00faban a szil\u00edcium-karbid ker\u00e1mi\u00e1r\u00f3l kider\u00fclt, hogy reduk\u00e1l\u00f3szerk\u00e9nt \u00e9s f\u0171t\u0151elemk\u00e9nt is haszn\u00e1lhat\u00f3 az ac\u00e9lgy\u00e1rt\u00e1sban, ami el\u0151seg\u00edtette gyors fejl\u0151d\u00e9s\u00e9t. A tov\u00e1bbi kutat\u00e1sok sor\u00e1n kider\u00fclt, hogy sz\u00e1mos kiv\u00e1l\u00f3 tulajdons\u00e1ggal rendelkezik, p\u00e9ld\u00e1ul magas h\u0151m\u00e9rs\u00e9kleti stabilit\u00e1ssal, nagy h\u0151vezet\u0151 k\u00e9pess\u00e9ggel, sav- \u00e9s l\u00fagkorr\u00f3zi\u00f3\u00e1ll\u00f3s\u00e1ggal, alacsony t\u00e1gul\u00e1si egy\u00fctthat\u00f3val \u00e9s j\u00f3 h\u0151sokk\u00e1ll\u00f3s\u00e1ggal.<\/p>\n
A szil\u00edciumkarbidnak f\u0151k\u00e9nt k\u00e9t krist\u00e1lyform\u00e1ja van: a k\u00f6b\u00f6s \u03b2- SIC4 \u00e9s a hexagon\u00e1lis \u03b1- SIC\u3002 A szil\u00edciumkarbid r\u00e1cs\u00e1nak alapvet\u0151 szerkezeti egys\u00e9gei az egym\u00e1st \u00e1that\u00f3 SIC4 \u00e9s CSI4 tetra\u00e9derek. A tetra\u00e9derek egyazon \u00e9len osztoznak, \u00edgy egy s\u00edkbeli r\u00e9teget alkotnak, \u00e9s a cs\u00facsok a k\u00f6vetkez\u0151 tetra\u00e9derr\u00e9teggel kapcsol\u00f3dva h\u00e1romdimenzi\u00f3s mechanizmust alkotnak. Mivel a k\u00fcl\u00f6nb\u00f6z\u0151 tetra\u00e9derek egym\u00e1sra rak\u00e1si sorrendjei k\u00fcl\u00f6nb\u00f6z\u0151 strukt\u00far\u00e1kat alkothatnak, eddig t\u00f6bb sz\u00e1z v\u00e1ltozatot tal\u00e1ltak. \u00c1ltal\u00e1ban t\u00f6m\u00f6r \u00e9s intuit\u00edv szimb\u00f3lumokat, nevezetesen a C, H, R bet\u0171ket haszn\u00e1lj\u00e1k a r\u00e1cst\u00edpus \u00e1br\u00e1zol\u00e1s\u00e1ra, \u00e9s az egys\u00e9gcell\u00e1ban tal\u00e1lhat\u00f3 r\u00e9tegek sz\u00e1m\u00e1t haszn\u00e1lj\u00e1k a k\u00fcl\u00f6nbs\u00e9g bemutat\u00e1s\u00e1ra. B\u00e1r ezeknek a polimorfoknak a r\u00e1cs\u00e1lland\u00f3i elt\u00e9r\u0151ek, a benn\u00fck l\u00e9v\u0151 anyagokban nincs nyilv\u00e1nval\u00f3 v\u00e1ltoz\u00e1s. a szil\u00edcium-karbid ker\u00e1mia tipikus valencia vegy\u00fclet, de vannak ionos t\u00edpusok is. Az elm\u00e9leti sz\u00e1m\u00edt\u00e1sok szerint az SI-C k\u00f6t\u00e9s teljes energi\u00e1j\u00e1b\u00f3l 78% kovalens \u00e1llapotba, 22% pedig ionos \u00e1llapotba tartozik. Az S \u00e9s C atomok kis m\u00e9rete, a k\u00f6t\u00e9shossz \u00e9s az er\u0151s kovalencia miatt a szil\u00edcium-karbid ker\u00e1mia egy sor jellemz\u0151vel rendelkezik, mint p\u00e9ld\u00e1ul nagy kem\u00e9nys\u00e9g, bizonyos mechanikai szil\u00e1rds\u00e1g \u00e9s neh\u00e9z szinterez\u00e9s.<\/p>\n
A szil\u00edciumkarbid tipikus kovalens k\u00f6t\u00e9ssel k\u00f6t\u00f6tt stabil vegy\u00fclet. Ezenk\u00edv\u00fcl diff\u00fazi\u00f3s egy\u00fctthat\u00f3ja alacsony, ami megnehez\u00edti a hagyom\u00e1nyos szinterel\u00e9si m\u00f3dszerekkel t\u00f6rt\u00e9n\u0151 s\u0171r\u00edt\u00e9s\u00e9t. A s\u0171r\u0171 szil\u00edcium-karbid ker\u00e1mi\u00e1k el\u0151\u00e1ll\u00edt\u00e1s\u00e1hoz n\u00e9h\u00e1ny szinterel\u00e9si seg\u00e9danyagot kell hozz\u00e1adni a fel\u00fcleti energia vagy a fel\u00fclet n\u00f6vel\u00e9se \u00e9rdek\u00e9ben, \u00e9s speci\u00e1lis elj\u00e1r\u00e1sokat kell alkalmazni. A szinterel\u00e9si elj\u00e1r\u00e1s szerint a szil\u00edcium-karbidot \u00e1tkrist\u00e1lyos\u00edtott szil\u00edcium-karbid ker\u00e1mi\u00e1kra, reakci\u00f3val szinterezett szil\u00edcium-karbid ker\u00e1mi\u00e1kra, nyom\u00e1s n\u00e9lk\u00fcli szinterezett szil\u00edcium-karbid ker\u00e1mi\u00e1kra, forr\u00f3n sajtolt szinterezett szil\u00edcium-karbid ker\u00e1mi\u00e1kra, magas h\u0151m\u00e9rs\u00e9kleten forr\u00f3n izosztatikusan sajtolt szinterezett szil\u00edcium-karbid ker\u00e1mi\u00e1kra \u00e9s k\u00e9miai g\u0151zf\u00e1zis\u00fa szil\u00edcium-karbidra lehet osztani. A k\u00fcl\u00f6nb\u00f6z\u0151 elj\u00e1r\u00e1sokkal el\u0151\u00e1ll\u00edtott szil\u00edcium-karbid tulajdons\u00e1gai meglehet\u0151sen elt\u00e9r\u0151ek, azaz az azonos elj\u00e1r\u00e1ssal el\u0151\u00e1ll\u00edtott SIC a k\u00fcl\u00f6nb\u00f6z\u0151 nyersanyagok \u00e9s adal\u00e9kanyagok miatt rossz teljes\u00edtm\u00e9nyt mutat.<\/p>","protected":false},"excerpt":{"rendered":"
Structural ceramics, also known as engineering ceramics, are a class of advanced ceramics that mainly exert the mechanical, thermal, 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-7","post","type-post","status-publish","format-standard","hentry","category-product-related"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/posts\/7","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/comments?post=7"}],"version-history":[{"count":4,"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/posts\/7\/revisions"}],"predecessor-version":[{"id":11,"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/posts\/7\/revisions\/11"}],"wp:attachment":[{"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/media?parent=7"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/categories?post=7"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/hu\/wp-json\/wp\/v2\/tags?post=7"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}