Sil\u012bcija karb\u012bds (saukts ar\u012b par karborundu) ir neorganisks \u0137\u012bmisks savienojums, kas sast\u0101v no sil\u012bcija un oglek\u013ca atomiem, dab\u0101 sastopams k\u0101 moizan\u012bts un kop\u0161 1893. gada masveid\u0101 ra\u017eots k\u0101 abraz\u012bvs.<\/p>\n
SiC past\u0101v vair\u0101k nek\u0101 70 krist\u0101lisk\u0101s form\u0101s, kas iedal\u0101s divos polimorfos: alfa sil\u012bcija karb\u012bds (a-SiC) un beta sil\u012bcija karb\u012bds (b-SiC). Eksperiment\u0101l\u0101s k\u013c\u016bdas robe\u017e\u0101s abas formas k\u016bst vienlaic\u012bgi pie spiediena l\u012bdz 10 GPa.<\/p>\n
Sil\u012bcija karb\u012bds ir \u0101rk\u0101rt\u012bgi ciets un bl\u012bvs materi\u0101ls ar daudzveid\u012bgu pielietojumu. To var atrast t\u0101dos izstr\u0101d\u0101jumos k\u0101 smil\u0161pap\u012brs, sl\u012bpripas, griez\u0113jinstrumenti, automobi\u013cu deta\u013cas un automobi\u013cu ugunsiztur\u012bgie materi\u0101li; turkl\u0101t tas kalpo k\u0101 ugunsiztur\u012bgais materi\u0101ls kr\u0101sn\u012bs, kr\u0101sn\u012bs un ugunsiztur\u012bgajos oder\u0113jumos, k\u0101 ar\u012b k\u0101 astronomisko teleskopu spogu\u013cu materi\u0101ls, pateicoties t\u0101 ciet\u012bbai un zemajam termisk\u0101s izple\u0161an\u0101s koeficientam.<\/p>\n
Edvards Goodrichs A\u010dons pirmo reizi masveid\u0101 sil\u012bcija karb\u012bdu izgatavoja 1891. gad\u0101, kad elektriskaj\u0101 kr\u0101sn\u012b kars\u0113ja m\u0101la un pulverveida koksa (oglek\u013ca) mais\u012bjumu, ieg\u016bstot zili melnu materi\u0101lu, kas paz\u012bstams k\u0101 \"karborunds\".<\/p>\n
Sil\u012bcija karb\u012bda ku\u0161anas p\u0113t\u012bjumi pie spiediena no 5 l\u012bdz 8 GPa atkl\u0101ja, ka tas k\u016bst kongruenti pie visiem p\u0113t\u012btajiem spiedieniem, un t\u0101 ku\u0161anas l\u012bknei ir negat\u012bvs sl\u012bpums -44 + 4 K\/GPa, sniedzot pier\u0101d\u012bjumus tam, ka bl\u012bvuma funkcion\u0101l\u0101 teorija to prec\u012bzi paredz\u0113ja.<\/p>\n
Sil\u012bcija karb\u012bds (SiC) ir keramikas materi\u0101ls, kas nav oks\u012bds un kam piem\u012bt izcilas \u012bpa\u0161\u012bbas, kas padara to noder\u012bgu daudzos augstas temperat\u016bras lietojumos. SiC ir gan ciets, gan \u013coti iztur\u012bgs, un t\u0101 polikrist\u0101lisk\u0101 \u0137erme\u0146a stipr\u012bba sasniedz 27 GPa; turkl\u0101t tam piem\u012bt izcilas r\u0113po\u0161anas pretest\u012bbas \u012bpa\u0161\u012bbas un zems termisk\u0101s izple\u0161an\u0101s koeficients.<\/p>\n
Keramika ar keramikas sast\u0101vu no keramisk\u0101 dioks\u012bda (CeO2) ne\u0161\u0137\u012bst \u016bden\u012b, bet \u0161\u0137\u012bst izkaus\u0113tos s\u0101rmu un dzelzs \u0161\u0137\u012bdumos, padarot to par visciet\u0101ko no vis\u0101m modernaj\u0101m struktur\u0101laj\u0101m keramik\u0101m ar iztur\u012bbu pret nodilumu, koroziju, triecieniem un termisko izple\u0161anos augst\u0101 spiedien\u0101; tas ir ide\u0101li piem\u0113rots izmanto\u0161anai augsttemperat\u016bras lietojumos, piem\u0113ram, kodolreaktoru komponentos.<\/p>\n
Sil\u012bcija karb\u012bdu, ko bie\u017e\u0101k d\u0113v\u0113 par a-SiC, parasti izmanto elektrisko transportl\u012bdzek\u013cu bremz\u0113s un saj\u016bgos, k\u0101 ar\u012b lo\u017eu necaur\u0161aujo\u0161\u0101s vest\u0113s, un to izmanto ar\u012b k\u0101 substr\u0101tu heterog\u0113najiem katalizatoriem. \u0160\u0101 materi\u0101la ra\u017eo\u0161ana r\u016bpnieciskos apjomos joproj\u0101m ir saist\u012bta ar elektriskaj\u0101m kr\u0101sn\u012bm, kur\u0101s izmanto t\u012bras sil\u012bcija smiltis, kas tiek reduc\u0113tas ar smalki samaltu koksu elektriskaj\u0101 kr\u0101sn\u012b; r\u016bpnieciska m\u0113roga sil\u012bcija karb\u012bda ra\u017eo\u0161ana joproj\u0101m ir popul\u0101ra izv\u0113le augstsprieguma lietojumiem energoelektronik\u0101.<\/p>\n
Sil\u012bcija karb\u012bds, paz\u012bstams ar\u012b k\u0101 sil\u012bcija dioks\u012bds, ir ciets \u0137\u012bmisks savienojums, kas sast\u0101v no sil\u012bcija un oglek\u013ca un dab\u0101 sastopams k\u0101 miner\u0101ls moizan\u012bts, bet kop\u0161 1893. gada tiek masveid\u0101 ra\u017eots k\u0101 pulveris un krist\u0101li, ko izmanto k\u0101 abraz\u012bvu un lo\u017eu necaurlaid\u012bgu vestu keramikas pl\u0101k\u0161\u0146u materi\u0101lu. Lielus monokrist\u0101lu graudus var savienot, tos sa\u0137epinot, lai ieg\u016btu \u0101rk\u0101rt\u012bgi iztur\u012bgu struktur\u0101lo keramiku; turkl\u0101t to bie\u017ei izmanto sint\u0113tisko moisan\u012bta d\u0101rgakme\u0146u izgatavo\u0161anai, kas paz\u012bstami k\u0101 sint\u0113tiskie moisan\u012bta d\u0101rgakme\u0146i. Sil\u012bcija karb\u012bds darbojas ar\u012b k\u0101 pusvad\u012bt\u0101js; to doping\u0113jot ar sl\u0101pekli vai fosforu, to var padar\u012bt par n-tipa materi\u0101lu; l\u012bdz\u012bgi berilijs, bors vai alum\u012bnijs to var p\u0101rveidot par p-tipa materi\u0101lu atkar\u012bb\u0101 no t\u0101 \u012bpa\u0161\u012bb\u0101m to dopingu var p\u0101rveidot par n-tipa pusvad\u012bt\u0101ju materi\u0101lu.<\/p>\n
Sil\u012bcija karb\u012bdam ir pla\u0161a joslas sprauga un augsta elektrisk\u0101 lauka sadal\u012b\u0161an\u0101s iztur\u012bba, t\u0101p\u0113c tas ir piem\u0113rots elektronikas ier\u012bc\u0113m, kas darbojas \u013coti augst\u0101s temperat\u016br\u0101s vai pie \u013coti augsta sprieguma. Turkl\u0101t t\u0101 termisko triecienu notur\u012bba noz\u012bm\u0113, ka tas ir pla\u0161i izmantots. Sil\u012bcija karb\u012bdam ir da\u017e\u0101das vien\u012bbas \u0161\u016bnas (kubiskas, rombiskas vai heksagon\u0101las). Ja to sabl\u012bv\u0113, izmantojot m\u0101lu, tas var kav\u0113t kakli\u0146u aug\u0161anu, vienlaikus nov\u0113r\u0161ot SiO2 veido\u0161anos, kas cit\u0101di samazin\u0101tu elast\u012bbas moduli. Da\u017e\u0101dos p\u0113t\u012bjumos, izmantojot ab initio molekul\u0101r\u0101s dinamikas simul\u0101cijas, kas balst\u012btas uz bl\u012bvuma funkcion\u0101l\u0101s teorijas simul\u0101cij\u0101m, ir p\u0113t\u012bta t\u0101 ku\u0161anas iztur\u012bba augst\u0101 spiedien\u0101.<\/p>\n
Sil\u012bcija karb\u012bds ir \u0101rk\u0101rt\u012bgi ciets un stingrs keramikas materi\u0101ls, ko raksturo augsta temperat\u016bras iztur\u012bba, zems termisk\u0101s izple\u0161an\u0101s koeficients un iztur\u012bba pret \u0137\u012bmisk\u0101m reakcij\u0101m. Tas ir pieejams da\u017e\u0101dos izm\u0113ros un form\u0101s, tostarp granulu veid\u0101, ko var ieg\u0101d\u0101ties, k\u0101 ar\u012b pl\u0101ksn\u012bt\u0113s, no kur\u0101m var izgatavot spogu\u013cus lieliem teleskopiem. Sil\u012bcija karb\u012bda ra\u017eo\u0161anas metodes ir da\u017e\u0101das - no tie\u0161as oglek\u013ca sint\u0113zes l\u012bdz \u0137\u012bmiskai tvaiku uzkl\u0101\u0161anai.<\/p>\n
Tika veikti p\u0113t\u012bjumi par Debye temperat\u016bras atkar\u012bbu no spiediena ZB un RS SiC no 3100+40 K l\u012bdz 5-8 GPa, izmantojot sl\u0101p\u0113\u0161anas eksperimentus un in situ m\u0113r\u012bjumus, izmantojot sl\u0101p\u0113\u0161anas eksperimentus un in situ m\u0113r\u012bjumus temperat\u016br\u0101 no 3100+40 K l\u012bdz 5-8 GPa. Rezult\u0101ti liecina, ka pie apk\u0101rt\u0113j\u0101 spiediena abas Lama konstantes (l, m) ir pozit\u012bvas, pieaugot m novirzei, kas liecina par to, ka pie augst\u0101ka spiediena palielin\u0101s necentrisko daudzu \u0137erme\u0146u sp\u0113ku sp\u0113ks, kas ietver l\u0101di\u0146a p\u0101rneses mijiedarb\u012bbu, k\u0101 rezult\u0101t\u0101 meh\u0101niski pastiprin\u0101s SiC saspie\u017eam\u012bba.<\/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\/lv\/wp-json\/wp\/v2\/posts\/66","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/comments?post=66"}],"version-history":[{"count":1,"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/posts\/66\/revisions"}],"predecessor-version":[{"id":67,"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/posts\/66\/revisions\/67"}],"wp:attachment":[{"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/media?parent=66"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/categories?post=66"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbideceramic.net\/lv\/wp-json\/wp\/v2\/tags?post=66"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}