Sil\u012bcija karb\u012bds jeb karborunds () ir cieta keramika, kas pirmo reizi masveid\u0101 tika ra\u017eota 1893. gad\u0101, lai to izmantotu k\u0101 abraz\u012bvu. Lai gan past\u0101v dabiski eksempl\u0101ri (moisan\u012bta d\u0101rgakme\u0146i un neliels daudzums k\u0101 vulk\u0101nisks iezis, ko sauc par korundu), m\u016bsdien\u0101s liel\u0101koties tiek izmantots sint\u0113tiski.<\/p>\n
SiC ir paz\u012bstams ar augstu iztur\u012bbu pret nogurumu, augstu siltumvad\u012btsp\u0113ju un zemu izple\u0161an\u0101s koeficientu, t\u0101p\u0113c tas ir piem\u0113rots ra\u017eo\u0161anai, lai iztur\u0113tu augstas temperat\u016bras, vienlaikus saglab\u0101jot iztur\u012bbu koroz\u012bv\u0101 vid\u0113.<\/p>\n
Sil\u012bcija karb\u012bds ir viens no nedaudzajiem materi\u0101liem ar augstu siltumvad\u012btsp\u0113ju istabas temperat\u016br\u0101. T\u0101 k\u0101 sil\u012bcija karb\u012bds ir ciets, stingrs un temperat\u016bras zi\u0146\u0101 stabils, tas ir lielisks materi\u0101ls astronomu izmantoto teleskopu spogu\u013cu izgatavo\u0161anai.<\/p>\n
Lai sistem\u0101tiski teor\u0113tiski izp\u0113t\u012btu kubisk\u0101 sil\u012bcija karb\u012bda (3C-SiC) struktur\u0101los parametrus un termofizik\u0101l\u0101s \u012bpa\u0161\u012bbas gal\u012bgaj\u0101 temperat\u016br\u0101, tika izmantota bl\u012bvuma funkcion\u0101l\u0101 teorija. M\u016bsu rezult\u0101ti attiec\u012bb\u0101 uz elast\u012bbas konstant\u0113m un Knoopa mikrotr\u016bdumu par\u0101d\u012bja apmierino\u0161u atbilst\u012bbu eksperiment\u0101lajiem datiem, k\u0101 ar\u012b citur public\u0113tajiem apr\u0113\u0137inu rezult\u0101tiem.<\/p>\n
Izmantojot optimiz\u0113tus strukt\u016bras mode\u013cus, m\u0113s ieguv\u0101m ar\u012b atomu l\u012bme\u0146a apl\u0113ses par defektu veido\u0161an\u0101s ener\u0123ij\u0101m ZrC, TiC un SiC, izmantojot optimiz\u0113tus strukt\u016bras mode\u013cus. Rezult\u0101ti atkl\u0101ja, ka Debye temperat\u016bra samazin\u0101s, palielinoties defektu atomu skaitam, bet CZr antis\u012bta un VC defekti uzr\u0101da zem\u0101kas veido\u0161an\u0101s ener\u0123ijas nek\u0101 to analogie VSi un Sit defekti; to veido\u0161an\u0101s ener\u0123ijas samazin\u0101jums var ietekm\u0113t 3C-SiC strukt\u016bru iztur\u012bbu pret vienass un b\u012bdes deform\u0101ciju.<\/p>\n
Sil\u012bcija karb\u012bds ir viens no ciet\u0101kajiem un siltumvado\u0161\u0101kajiem materi\u0101liem, kas atrodams dab\u0101, un tas ir iztur\u012bgs gan pret sk\u0101bju, gan s\u0101rmu iedarb\u012bbu, turkl\u0101t ir karstumiztur\u012bgs l\u012bdz 1600 gr\u0101diem p\u0113c Celsija, nezaud\u0113jot iztur\u012bbu. Turkl\u0101t sil\u012bcija karb\u012bds ir lielisks elektrovad\u012bt\u0101js.<\/p>\n
Silicija karb\u012bda pla\u0161\u0101 joslas joslas sprauga padara to piem\u0113rotu izmanto\u0161anai t\u0101d\u0101s pusvad\u012bt\u0101ju ier\u012bc\u0113s k\u0101 diodes, tranzistori un tiristori, savuk\u0101rt t\u0101 sp\u0113ja iztur\u0113t lielu spriegumu un str\u0101vu padara to noder\u012bgu ar\u012b lieljaudas ener\u0123ijas ier\u012bc\u0113s.<\/p>\n
Poraino SiC var p\u0101rveidot, pievienojot graf\u0113na nanoplat\u012btes (GNP), t\u0101d\u0113j\u0101di radot materi\u0101lu ar uzlabot\u0101m termiskaj\u0101m \u012bpa\u0161\u012bb\u0101m. \u0160o materi\u0101lu var izgatavot, sa\u0137epinot \u0161\u0137idr\u0101s f\u0101zes dzirkste\u013cplazm\u0101 stehiometrisko vai nestehiometrisko SiC pulveri; tika p\u0101rbaud\u012btas da\u017e\u0101das sa\u0137epin\u0101\u0161anas pal\u012bgvielu (Y2O3 un La2O3) kombin\u0101cijas, lai nov\u0113rt\u0113tu to ietekmi uz porainu materi\u0101lu ar GNP saturu l\u012bdz 20 tilpuma % f\u0101\u017eu sast\u0101vu, mikrostrukt\u016bru un siltumvad\u012btsp\u0113ju; kompoz\u012btiem ar GNP saturu l\u012bdz 20% tika nov\u0113rota nemonotona temperat\u016bras atkar\u012bba.<\/p>\n
SiC unik\u0101lais sil\u012bcija un oglek\u013ca atomu sast\u0101vs t\u0101 krist\u0101lre\u017e\u0123\u012b pie\u0161\u0137ir tam iev\u0113rojamas meh\u0101nisk\u0101s \u012bpa\u0161\u012bbas, kas padara to par vienu no ciet\u0101kajiem un iztur\u012bg\u0101kajiem keramikas materi\u0101liem. SiC ir \u013coti iztur\u012bgs pret sk\u0101bju, s\u0101rmu, izkaus\u0113tu s\u0101\u013cu izrais\u012btu koroziju, k\u0101 ar\u012b pret nodilumu; stingr\u012bba un iztur\u012bba padara SiC par pievilc\u012bgu materi\u0101lu ar\u012b t\u0101diem nodilumiztur\u012bgiem komponentiem k\u0101 sl\u012bp\u0113\u0161anas diski vai urbji dzirnav\u0101s, ekspanderos vai ekstr\u016bderos.<\/p>\n
Keramikas materi\u0101ls ir viegls, turkl\u0101t tam piem\u012bt izcila iztur\u012bba pret termisko triecienu - tas var iztur\u0113t temperat\u016bru l\u012bdz 1600 gr\u0101diem p\u0113c Celsija, nezaud\u0113jot meh\u0101nisk\u0101s \u012bpa\u0161\u012bbas vai termisko izple\u0161anos, ar zemu termisk\u0101s izple\u0161an\u0101s \u0101trumu un \u0101rk\u0101rt\u012bgi augstu Junga moduli, kas nodro\u0161ina izm\u0113ru stabilit\u0101ti.<\/p>\n
Porain\u0101s SiC keramikas porain\u012bba at\u0161\u0137iras atkar\u012bb\u0101 no t\u0101s veido\u0161anas metodes (reakcijas saist\u012b\u0161ana vai sa\u0137epin\u0101\u0161ana). P\u0113t\u012bjumos ir pier\u0101d\u012bts, ka, palielinoties B4C saturam, palielin\u0101s gan elektrovad\u012btsp\u0113ja, gan stiepes iztur\u012bba, jo tas sp\u0113j adsorb\u0113t sk\u0101bekli no Si-C matricas materi\u0101liem un t\u0101d\u0113j\u0101di samazina fononu izkliedes garumu.<\/p>\n
Sil\u012bcija karb\u012bdu izmanto gan k\u0101 abraz\u012bvu, gan k\u0101 griez\u0113jinstrumentu ra\u017eo\u0161an\u0101. T\u0101 ciet\u0101s un karstumiztur\u012bg\u0101s virsmas d\u0113\u013c sil\u012bcija karb\u012bdu var izmantot ar\u012b k\u0101 elektronisko pusvad\u012bt\u0101ju diod\u0113s un tranzistoru sast\u0101v\u0101, jo t\u0101 sprieguma tolerance var p\u0101rsniegt sil\u012bcija toleranci.<\/p>\n
Sil\u012bcija karb\u012bda ciet\u012bba, iztur\u012bba pret koroziju un augst\u0101 siltumvad\u012btsp\u0113ja padara to par lielisku materi\u0101lu t\u0101diem aizsardz\u012bbas l\u012bdzek\u013ciem k\u0101 \u0137iveres un bru\u0146u pl\u0101ksnes. Turkl\u0101t t\u0101 \u0137\u012bmisk\u0101 inertums noz\u012bm\u0113, ka tas nerea\u0123\u0113 ar \u016bdeni, t\u0101p\u0113c ir ide\u0101li piem\u0113rots izmanto\u0161anai augsta mitruma apst\u0101k\u013cos, piem\u0113ram, kosmosa ku\u0123os un j\u016bras vid\u0113.<\/p>\n
P\u0101rkristaliz\u0113tais sil\u012bcija karb\u012bds (RSiC) var lepoties ar nep\u0101rsp\u0113jamu meh\u0101nisko, termisko un elektrisko \u012bpa\u0161\u012bbu kombin\u0101ciju, kas ir lab\u0101ka par citiem SiC variantiem. T\u0101 bl\u012bv\u0101 mikrostrukt\u016bra nodro\u0161ina RSiC zemu izple\u0161an\u0101s koeficientu, vienlaikus saglab\u0101jot iztur\u012bbu un stingr\u012bbu ar\u012b augst\u0101s temperat\u016br\u0101s; turkl\u0101t RSiC uzr\u0101da relat\u012bvi augst\u0101kas elast\u012bbas modu\u013ca v\u0113rt\u012bbas nek\u0101 struktur\u0101l\u0101 cirkonija keramika un tam ir zemas termisk\u0101s izple\u0161an\u0101s koeficienta v\u0113rt\u012bbas sal\u012bdzin\u0101jum\u0101 ar struktur\u0101lo cirkonija keramiku.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide, or carborundum (), is a hard ceramic first mass-produced in 1893 for use as an abrasive. While natural instances exist (moissanite gems and small quantities as an igneous rock called corundum), most modern day usage occurs synthetically. SiC is known to exhibit high fatigue resistance, high thermal conductivity and a low coefficient of […]<\/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":[64],"tags":[],"class_list":["post-190","post","type-post","status-publish","format-standard","hentry","category-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/posts\/190","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/comments?post=190"}],"version-history":[{"count":1,"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/posts\/190\/revisions"}],"predecessor-version":[{"id":191,"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/posts\/190\/revisions\/191"}],"wp:attachment":[{"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/media?parent=190"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/categories?post=190"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/lv\/wp-json\/wp\/v2\/tags?post=190"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}