Carbura de siliciu (denumit\u0103 \u0219i carborundum) este un compus chimic anorganic format din atomi de siliciu \u0219i carbon, care se g\u0103se\u0219te \u00een natur\u0103 sub form\u0103 de moissanite \u0219i care este produs \u00een mas\u0103 din 1893 pentru a fi utilizat ca abraziv.<\/p>\n
SiC exist\u0103 \u00een mai mult de 70 de forme cristaline, \u00eemp\u0103r\u021bite \u00een dou\u0103 polimorfe: carbur\u0103 de siliciu alfa (a-SiC) \u0219i carbur\u0103 de siliciu beta (b-SiC). \u00cen limitele erorii experimentale, ambele forme se topesc concomitent la presiuni de p\u00e2n\u0103 la 10 GPa.<\/p>\n
Carbura de siliciu este un material extrem de dur \u0219i dens cu aplica\u021bii multiple. Acesta poate fi g\u0103sit \u00een produse precum \u0219mirghel, discuri abrazive, unelte de t\u0103iere, componente auto \u0219i materiale refractare auto; \u00een plus, serve\u0219te ca material refractar \u00een cuptoare, cuptoare \u0219i c\u0103ptu\u0219eli refractare, precum \u0219i ca material pentru oglinzile telescoapelor astronomice datorit\u0103 durit\u0103\u021bii sale \u0219i ratei sc\u0103zute de dilatare termic\u0103.<\/p>\n
Edward Goodrich Acheson a produs primul carbur\u0103 de siliciu \u00een mas\u0103 \u00een 1891, c\u00e2nd a \u00eenc\u0103lzit un amestec de argil\u0103 \u0219i praf de cocs (carbon) \u00eentr-un cuptor electric, produc\u00e2nd un material negru-albastru cunoscut sub numele de \"carborundum\".<\/p>\n
Studiile privind topirea carburii de siliciu la presiuni cuprinse \u00eentre 5-8 GPa au ar\u0103tat c\u0103 aceasta se tope\u0219te congruent la toate presiunile studiate, curba sa de topire av\u00e2nd o pant\u0103 negativ\u0103 de -44 + 4 K\/GPa, furniz\u00e2nd dovezi c\u0103 teoria func\u021bional\u0103 a densit\u0103\u021bii a prezis cu exactitate.<\/p>\n
Carbura de siliciu (SiC) este un material ceramic non-oxid cu propriet\u0103\u021bi excep\u021bionale care \u00eel fac util \u00een multe aplica\u021bii la temperaturi ridicate. SiC este at\u00e2t dur, c\u00e2t \u0219i extrem de puternic, cu rezisten\u021be ale corpului policristalin de p\u00e2n\u0103 la 27 GPa; \u00een plus, are propriet\u0103\u021bi excelente de rezisten\u021b\u0103 la fluaj, \u00eempreun\u0103 cu rate sc\u0103zute de dilatare termic\u0103.<\/p>\n
Ceramica de dioxid de ceramiu (CeO2) este insolubil\u0103 \u00een ap\u0103, dar solubil\u0103 \u00een solu\u021bii alcaline \u0219i de fier topite, ceea ce o face cea mai dur\u0103 dintre toate ceramicile structurale avansate, cu rezisten\u021b\u0103 la abraziune, coroziune, impact \u0219i dilatare termic\u0103 la presiuni ridicate; ceea ce o face perfect\u0103 pentru utilizarea \u00een aplica\u021bii la temperaturi ridicate, cum ar fi componentele reactoarelor nucleare.<\/p>\n
Carbura de siliciu, denumit\u0103 mai frecvent a-SiC, se g\u0103se\u0219te \u00een mod obi\u0219nuit \u00een fr\u00e2nele \u0219i ambreiajele vehiculelor electrice, precum \u0219i \u00een vestele antiglon\u021b \u0219i este utilizat\u0103 ca substrat pentru catalizatori eterogeni. Produc\u021bia de cantit\u0103\u021bi industriale din acest material implic\u0103 \u00eenc\u0103 utilizarea cuptoarelor electrice cu nisip de siliciu pur redus cu cocs fin m\u0103cinat \u00eentr-un cuptor electric; produc\u021bia la scar\u0103 industrial\u0103 de carbur\u0103 de siliciu r\u0103m\u00e2ne o alegere popular\u0103 pentru aplica\u021bii de \u00eenalt\u0103 tensiune \u00een electronica de putere.<\/p>\n
Carbura de siliciu, cunoscut\u0103 \u0219i sub denumirea de dioxid de siliciu, este un compus chimic dur format din siliciu \u0219i carbon care se g\u0103se\u0219te \u00een stare natural\u0103 sub forma mineralului moissanite, dar care a fost produs \u00een mas\u0103 \u00eencep\u00e2nd cu 1893 sub form\u0103 de pulbere \u0219i cristal pentru a fi utilizat ca material abraziv \u0219i ca material pentru pl\u0103ci ceramice de vest\u0103 antiglon\u021b. Granulele mari, monocristaline, pot fi unite prin sinterizare pentru a produce ceramic\u0103 structural\u0103 extrem de dur\u0103; \u00een plus, este adesea utilizat pentru fabricarea pietrelor pre\u021bioase sintetice din moissanit\u0103, cunoscute sub denumirea de pietre pre\u021bioase sintetice din moissanit\u0103. Carbura de siliciu ac\u021bioneaz\u0103, de asemenea, ca un semiconductor; doparea sa cu azot sau fosfor \u00eel poate transforma \u00eentr-un material de tip n; \u00een mod similar, beriliul, borul sau aluminiul \u00eel pot modifica \u00een material de tip p, \u00een func\u021bie de caracteristicile sale, dopajul \u00eel va transforma \u00eentr-un material semiconductor de tip n.<\/p>\n
Carbura de siliciu are un interval de band\u0103 expansiv \u0219i o rezisten\u021b\u0103 ridicat\u0103 la ruperea c\u00e2mpului electric, ceea ce o face potrivit\u0103 pentru dispozitivele electronice care func\u021bioneaz\u0103 la temperaturi sau tensiuni extrem de ridicate. \u00cen plus, datorit\u0103 caracterului s\u0103u rezistent la \u0219ocuri termice, acesta este utilizat pe scar\u0103 larg\u0103. Carbura de siliciu exist\u0103 sub form\u0103 de diferite celule unitare (cubic\u0103, romboedric\u0103 sau hexagonal\u0103). Dac\u0103 este densificat cu ajutorul argilei, acesta poate inhiba cre\u0219terea g\u00e2tului, \u00eempiedic\u00e2nd \u00een acela\u0219i timp formarea SiO2, care altfel ar reduce modulul elastic. Diferite studii au examinat comportamentul de topire al carbidului de siliciu sub presiune ridicat\u0103 utiliz\u00e2nd simul\u0103ri de dinamic\u0103 molecular\u0103 ab initio bazate pe simul\u0103ri ale teoriei func\u021bionale a densit\u0103\u021bii.<\/p>\n
Carbura de siliciu este un material ceramic extrem de dur \u0219i rigid, caracterizat prin capacitatea sa de a rezista la temperaturi ridicate, coeficient sc\u0103zut de dilatare termic\u0103 \u0219i rezisten\u021b\u0103 la reac\u021bii chimice. Acesta este disponibil \u00een diferite dimensiuni \u0219i forme, inclusiv sub form\u0103 granular\u0103 pentru cump\u0103rare, precum \u0219i sub form\u0103 de plachete care pot fi transformate \u00een oglinzi pentru telescoape mari. Metodele de produc\u021bie pentru carbura de siliciu variaz\u0103 de la sinteza direct\u0103 a carbonului la depunerea chimic\u0103 \u00een stare de vapori.<\/p>\n
S-au efectuat studii privind dependen\u021ba de presiune a temperaturilor Debye \u00een ZB \u0219i RS SiC de la 3100+40 K la 5-8 GPa utiliz\u00e2nd experimente de stingere \u0219i m\u0103sur\u0103tori in situ la temperaturi cuprinse \u00eentre 3100+40 K \u0219i 5-8 GPa utiliz\u00e2nd experimente de stingere \u0219i m\u0103sur\u0103tori in situ. Rezultatele demonstreaz\u0103 c\u0103, la presiunea ambiant\u0103, ambele constante ale lui Lame (l, m) sunt pozitive cu o abatere cresc\u00e2nd\u0103 a lui m, ceea ce sugereaz\u0103 o rezisten\u021b\u0103 sporit\u0103 a for\u021belor noncentrale ale multor corpuri care implic\u0103 interac\u021biuni de transfer de sarcin\u0103 la presiuni mai mari, ceea ce duce la rigidizarea mecanic\u0103 a compresibilit\u0103\u021bii SiC.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide (also referred to as carborundum) is an inorganic chemical compound composed of silicon and carbon atoms, naturally found […]<\/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-66","post","type-post","status-publish","format-standard","hentry","category-product-related"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/posts\/66","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/comments?post=66"}],"version-history":[{"count":1,"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/posts\/66\/revisions"}],"predecessor-version":[{"id":67,"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/posts\/66\/revisions\/67"}],"wp:attachment":[{"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/media?parent=66"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/categories?post=66"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/ro\/wp-json\/wp\/v2\/tags?post=66"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}