{"id":50,"date":"2024-03-28T09:10:32","date_gmt":"2024-03-28T01:10:32","guid":{"rendered":"http:\/\/siliconcarbideceramic.net\/?p=50"},"modified":"2024-07-07T21:43:15","modified_gmt":"2024-07-07T13:43:15","slug":"proprietati-ale-carburii-de-siliciu","status":"publish","type":"post","link":"https:\/\/siliconcarbideceramic.net\/ro\/silicon-carbide-properties\/","title":{"rendered":"Propriet\u0103\u021bile carburii de siliciu"},"content":{"rendered":"<p>Carbura de siliciu (SiC) este un material extrem de durabil, cu o duritate pe scara Mohs de 9 \u0219i un aspect estetic care rivalizeaz\u0103 cu cel al diamantului.<\/p>\n<p>Laboratoarele EAG au o vast\u0103 experien\u021b\u0103 \u00een analizarea SiC pentru aceste propriet\u0103\u021bi, utiliz\u00e2nd tehnici analitice \u00een mas\u0103 \u0219i rezolvate spa\u021bial. Acesta poate servi at\u00e2t ca izolator electric, c\u00e2t \u0219i ca semiconductor.<\/p>\n<h2>Duritate<\/h2>\n<p>Carbura de siliciu este una dintre cele mai dure substan\u021be din lume, ocup\u00e2nd locul nou\u0103 pe scara Mohs \u0219i fiind a doua dup\u0103 diamant \u00een ceea ce prive\u0219te duritatea. Carbura de bor \u0219i diamantul sunt chiar mai dure dec\u00e2t carbura de siliciu - alte utiliz\u0103ri ale acesteia includ unelte de t\u0103iere, veste antiglon\u021b, piese auto \u0219i oglinzi pentru telescoape astronomice. Suprafa\u021ba dur\u0103 \u0219i rezistent\u0103 a carburii de siliciu este ideal\u0103 pentru utilizarea ca abraziv de t\u0103iere \u0219i unelte de t\u0103iere, materiale structurale (veste antiglon\u021b), piese auto \u0219i oglinzi utilizate de telescoape!<\/p>\n<p>Ceramica rezistent\u0103 la \u0219ocuri termice este o ceramic\u0103 extrem de dur\u0103, neoxidabil\u0103. Datorit\u0103 rezisten\u021bei sale, a conductivit\u0103\u021bii termice ridicate, a ratei sc\u0103zute de dilatare termic\u0103 \u0219i a rezisten\u021bei excelente la oxidare, aceasta devine un material refractar indispensabil.<\/p>\n<p>Carbura de siliciu (num\u0103rul atomic 14) \u0219i carbonul (num\u0103rul atomic 6) formeaz\u0103 un compus anorganic cunoscut sub numele de carbur\u0103 de siliciu, cu dou\u0103 tetraedre de coordonare primar\u0103 formate din patru atomi de carbon \u0219i patru atomi de siliciu lega\u021bi covalent, cre\u00e2nd o structur\u0103 compact\u0103 extrem de puternic\u0103 \u0219i rigid\u0103, cu rezisten\u021b\u0103 \u0219i rigiditate superioare; polipii s\u0103i se pot chiar stivui pentru a forma polipii. Carbura de siliciu ofer\u0103 propriet\u0103\u021bi de semiconductor cu band\u0103 larg\u0103 care necesit\u0103 de trei ori mai pu\u021bin\u0103 energie pentru a elibera electronii din st\u0103rile orbitale \u00een compara\u021bie cu siliciul.<\/p>\n<h2>Rezisten\u021ba la coroziune<\/h2>\n<p>Cea mai important\u0103 proprietate a carburii de siliciu este rezisten\u021ba sa la coroziune. Nu numai c\u0103 este rezistent la cei mai agresivi acizi (clorhidric, sulfuric \u0219i fluorhidric), baze \u0219i solven\u021bi imaginabili - precum \u0219i la medii oxidante cum ar fi acidul azotic sau aburul - dar se m\u00e2ndre\u0219te \u0219i cu propriet\u0103\u021bi excelente de izolare \u00eempotriva deterior\u0103rii cauzate de temperaturi extreme sau c\u00e2mpuri electrice.<\/p>\n<p>Carbura de siliciu sinterizat\u0103 ofer\u0103 o rezisten\u021b\u0103 termic\u0103 excelent\u0103 datorit\u0103 naturii sale dense, durit\u0103\u021bii, caracteristicilor semiconductoare de band\u0103 larg\u0103 care permit un consum redus de energie electronic\u0103 pentru deplasarea benzii de conduc\u021bie \u0219i coeficientului s\u0103u sc\u0103zut de dilatare termic\u0103.<\/p>\n<p>Rezisten\u021ba la coroziune poate fi, de asemenea, \u00eembun\u0103t\u0103\u021bit\u0103 prin prezen\u021ba aditivilor de sinterizare, a fazelor de delimitare a granulelor \u0219i a porozit\u0103\u021bii; tipul \u0219i cantitatea acestora depinde de rapiditatea cu care coroziunea reac\u021bioneaz\u0103 cu alte medii.<\/p>\n<p>St\u0103rile de oxidare ale carburii de siliciu pot fi controlate prin ac\u021biunea carbonului ca agent pasivant, contribuind la reducerea ratelor de coroziune \u0219i la prelungirea duratei de via\u021b\u0103 a produsului atunci c\u00e2nd este expus la medii oxidante \u00een exploatare.<\/p>\n<h2>Conductivitate termic\u0103<\/h2>\n<p>Carbura de siliciu este un material extrem de dur, situ\u00e2ndu-se undeva \u00eentre alumin\u0103 (9 pe scara Mohs) \u0219i diamant (10). Datorit\u0103 combina\u021biei sale de duritate \u0219i stabilitate termic\u0103, carbura de siliciu reprezint\u0103 o alegere excelent\u0103 de material pentru aplica\u021bii mecanice exigente \u00een piese concepute pentru a rezista la materiale rezistente la uzur\u0103, precum \u0219i la materiale refractare.<\/p>\n<p>De asemenea, datorit\u0103 rezisten\u021bei sale excelente la \u0219ocurile termice \u0219i a ratei sc\u0103zute de dilatare termic\u0103, cauciucul siliconic este potrivit pentru utilizarea \u00een medii cu temperaturi ridicate \u0219i componente utilizate \u00een sistemele de conducte.<\/p>\n<p>Carbura de siliciu poate fi dopat\u0103 cu diferite elemente pentru a-i modifica propriet\u0103\u021bile electronice. Doparea cu azot sau fosfor \u00eel va transforma \u00eentr-un semiconductor de tip n, \u00een timp ce dopajul cu beriliu, bor sau aluminiu \u00eel va transforma \u00eentr-un semiconductor de tip p.<\/p>\n<p>Diferen\u021ba de bandgap dintre benzile de valen\u021b\u0103 \u0219i de conduc\u021bie ale carburii de siliciu \u00eengreuneaz\u0103 comutarea electronilor \u00eentre cele dou\u0103 benzi, permi\u021b\u00e2ndu-i s\u0103 suporte p\u00e2n\u0103 la de 10 ori mai multe c\u00e2mpuri electrice dec\u00e2t siliconul \u00eenainte de a deveni fragil \u0219i de a se rupe.<\/p>\n<h2>Conductivitate electric\u0103<\/h2>\n<p>Carbura de siliciu ofer\u0103 o gam\u0103 de propriet\u0103\u021bi electrice care pot fi adaptate prin dopare. Doparea presupune ad\u0103ugarea de impurit\u0103\u021bi \u00een structura cristalin\u0103 pentru a forma electroni \u0219i g\u0103uri libere care conduc electricitatea, oferind SiC valori de conductivitate de zece ori mai mari dec\u00e2t cele ale siliciului.<\/p>\n<p>Propriet\u0103\u021bile electrice ale carburii de siliciu sunt determinate \u00een mare m\u0103sur\u0103 de intervalul s\u0103u de band\u0103. Aceast\u0103 diferen\u021b\u0103 dintre nivelurile energetice ale benzii de valen\u021b\u0103 \u0219i ale benzii de conduc\u021bie a unui atom determin\u0103 c\u00e2mpul electric pe care \u00eel poate suporta; carbura de siliciu se m\u00e2ndre\u0219te cu un band-gap mai larg dec\u00e2t omologul s\u0103u din siliciu, ceea ce \u00eei permite s\u0103 tolereze o tensiune de aproape dou\u0103 ori mai mare.<\/p>\n<p>Rezisten\u021ba ridicat\u0103 la tensiune face ca neodimul s\u0103 fie ideal pentru utilizarea \u00een dispozitivele de alimentare a vehiculelor electrice, oferind distan\u021be mai lungi de conducere \u0219i o eficien\u021b\u0103 sporit\u0103 a gestion\u0103rii bateriei. \u00cen plus, greutatea sa mai redus\u0103 comparativ cu alternative precum nitrurile de galiu permite produc\u0103torilor de electronice de putere s\u0103 reduc\u0103 semnificativ dimensiunile \u0219i greutatea, rezist\u00e2nd \u00een acela\u0219i timp la temperaturi ridicate cu un coeficient minim de dilatare termic\u0103.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-186\" src=\"http:\/\/siliconcarbideceramic.net\/wp-content\/uploads\/2024\/03\/Silicon-Carbide-Properties.jpg\" alt=\"Propriet\u0103\u021bile carburii de siliciu\" width=\"1920\" height=\"1920\" srcset=\"https:\/\/siliconcarbideceramic.net\/wp-content\/uploads\/2024\/03\/Silicon-Carbide-Properties.jpg 1920w, https:\/\/siliconcarbideceramic.net\/wp-content\/uploads\/2024\/03\/Silicon-Carbide-Properties-300x300.jpg 300w, https:\/\/siliconcarbideceramic.net\/wp-content\/uploads\/2024\/03\/Silicon-Carbide-Properties-1024x1024.jpg 1024w, https:\/\/siliconcarbideceramic.net\/wp-content\/uploads\/2024\/03\/Silicon-Carbide-Properties-150x150.jpg 150w, https:\/\/siliconcarbideceramic.net\/wp-content\/uploads\/2024\/03\/Silicon-Carbide-Properties-768x768.jpg 768w, https:\/\/siliconcarbideceramic.net\/wp-content\/uploads\/2024\/03\/Silicon-Carbide-Properties-1536x1536.jpg 1536w, https:\/\/siliconcarbideceramic.net\/wp-content\/uploads\/2024\/03\/Silicon-Carbide-Properties-12x12.jpg 12w\" sizes=\"auto, (max-width: 1920px) 100vw, 1920px\" \/><\/p>","protected":false},"excerpt":{"rendered":"<p>Silicon Carbide (SiC) is an extremely durable material with an extremely hard Mohs scale hardness rating of 9 and an [&hellip;]<\/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":"default","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":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","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 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