Karbid krem\u00edka (SiC) je tvrd\u00e1 chemick\u00e1 zl\u00fa\u010denina pozost\u00e1vaj\u00faca z krem\u00edka a uhl\u00edka, ktor\u00e1 sa v pr\u00edrode vyskytuje ako drahokam moissanit a masovo sa vyr\u00e1ba na pou\u017eitie v abraz\u00edvach, metalurgick\u00fdch aplik\u00e1ci\u00e1ch a \u017eiaruvzdorn\u00fdch materi\u00e1loch.<\/p>\n
SiC je ide\u00e1lny pre \u0161amotov\u00e9 tehly a in\u00e9 \u017eiaruvzdorn\u00e9 v\u00fdrobky v\u010faka svojej odolnosti vo\u010di vysok\u00fdm teplot\u00e1m a tepeln\u00fdm \u0161okom, polovodivej povahe a at\u00f3movej \u0161trukt\u00fare, ktor\u00e1 ho rob\u00ed \u017eiaruvzdorn\u00fdm.<\/p>\n
Karbid krem\u00edka, \u010dastej\u0161ie ozna\u010dovan\u00fd ako karborundum alebo SiC, je keramick\u00fd materi\u00e1l so \u0161truktur\u00e1lnymi aj polovodi\u010dov\u00fdmi vlastnos\u0165ami. V\u010faka svojej pevnosti, odolnosti vo\u010di vysok\u00fdm teplot\u00e1m a chemickej inertnosti aj pri zv\u00fd\u0161en\u00fdch teplot\u00e1ch je SiC vynikaj\u00facim materi\u00e1lom pre aplik\u00e1cie v oblasti br\u00fasnych materi\u00e1lov, metalurgie a \u017eiaruvzdorn\u00fdch materi\u00e1lov; okrem toho sa v\u010faka svojim vlastnostiam podobn\u00fdm polovodi\u010dom hod\u00ed pre vysoko v\u00fdkonn\u00e9 zariadenia pracuj\u00face pri teplot\u00e1ch, ktor\u00e9 be\u017en\u00e9 polovodi\u010de nezvl\u00e1daj\u00fa.<\/p>\n
SiC sa m\u00f4\u017ee vyr\u00e1ba\u0165 r\u00f4znymi v\u00fdrobn\u00fdmi technikami, pri\u010dom ka\u017ed\u00e1 z nich pon\u00faka odli\u0161n\u00e9 v\u00fdhody pre konkr\u00e9tne aplik\u00e1cie. Napr\u00edklad Achesonov proces pon\u00faka komplexn\u00e9 tvary s vysokou pevnos\u0165ou; proces reak\u010dne viazan\u00e9ho karbidu krem\u00edka (RBSC) poskytuje vysok\u00fa \u010distotu; zatia\u013e \u010do chemick\u00e9 naparovanie pon\u00faka potenci\u00e1l na vytv\u00e1ranie ultra\u010dist\u00fdch povlakov.<\/p>\n
Pri komer\u010dnej v\u00fdrobe karbidu krem\u00edka sa zvy\u010dajne pou\u017e\u00edva proces elektrickej pece s n\u00edzkopopolov\u00fdm ropn\u00fdm koksom ako zdrojom uhl\u00edka, ktor\u00fd sa pred trieden\u00edm a chemickou \u00fapravou na splnenie \u0161pecifick\u00fdch v\u00fdkonnostn\u00fdch charakterist\u00edk rozdrv\u00ed a pomelie.<\/p>\n
Krem\u00edk a uhl\u00edk chemicky reaguj\u00fa v surovin\u00e1ch a vytv\u00e1raj\u00fa polytypy alebo usporiadanie prvkov na sebe, pri\u010dom kubick\u00fd karbid krem\u00edka (a-SiC) je jedn\u00fdm z najob\u013e\u00fabenej\u0161\u00edch polytypov s tvrdos\u0165ou pod\u013ea Mohsa 9. Hoci surov\u00e9 miner\u00e1ly tohto druhu sa m\u00f4\u017eu \u0165a\u017ei\u0165 ako zdroje nerastn\u00fdch surov\u00edn, naj\u010dastej\u0161ie sa vyr\u00e1baj\u00fa kombinovan\u00fdmi procesmi: reak\u010dn\u00fdm sp\u00e1jan\u00edm a spekan\u00edm.<\/p>\n
Reak\u010dn\u00e1 v\u00e4zba je proces, pri ktorom sa zmes mlet\u00e9ho kremi\u010dit\u00e9ho piesku a uhl\u00edka vo forme n\u00edzkopopolov\u00e9ho ropn\u00e9ho koksu kombinuje a vytv\u00e1ra okolo elektrickej odporovej pece prostredn\u00edctvom reak\u010dnej v\u00e4zby. Elektrick\u00fd pr\u00fad potom prech\u00e1dza vodi\u010dom, \u010d\u00edm sa spust\u00ed chemick\u00e1 reakcia a vznikne valcov\u00fd ingot a-SiC aj b-SiC; pr\u00edpadn\u00fd nezreagovan\u00fd a-SiC zost\u00e1va na povrchu ingotu. Potom sa prid\u00e1 kvapaln\u00fd krem\u00edk, ktor\u00fd spoj\u00ed p\u00f4vodne oddelen\u00e9 kry\u0161t\u00e1ly do jednej s\u00favislej \u0161trukt\u00fary kubick\u00fdch kry\u0161t\u00e1lov SiC, ktor\u00e1 je vhodn\u00e1 na v\u00e4\u010d\u0161inu priemyseln\u00fdch pou\u017eit\u00ed; niekedy m\u00f4\u017ee d\u00f4js\u0165 k \u010fal\u0161iemu spracovaniu na v\u00fdrobu materi\u00e1lu metalurgickej kvality.<\/p>\n
Karbid krem\u00edka (SiC) je anorganick\u00e1 chemick\u00e1 zl\u00fa\u010denina zlo\u017een\u00e1 z uhl\u00edka a krem\u00edka, ktor\u00e1 sa v pr\u00edrode vyskytuje ako vz\u00e1cny miner\u00e1l moissanit; od roku 1893 sa v\u0161ak vyr\u00e1ba aj synteticky vo forme pr\u00e1\u0161ku, ktor\u00fd sa pou\u017e\u00edva ako br\u00fasivo. Karbid krem\u00edka sa m\u00f4\u017ee pochv\u00e1li\u0165 najtvrd\u0161\u00edm syntetick\u00fdm materi\u00e1lom, ktor\u00fd je na Mohsovej stupnici tvrdosti zaraden\u00fd medzi oxid hlinit\u00fd a diamant, a v\u010faka svojej tepelnej vodivosti, n\u00edzkej tepelnej roz\u0165a\u017enosti a chemickej inertnosti je ve\u013emi vhodn\u00fd na priemyseln\u00e9 \u017eiaruvzdorn\u00e9 aplik\u00e1cie, napr\u00edklad na v\u00fdrobu pecn\u00fdch teh\u00e1l.<\/p>\n
V\u00fdroba SiC metalurgickej kvality sa zvy\u010dajne vykon\u00e1va Achesonov\u00fdm procesom, ktor\u00fd zah\u0155\u0148a mie\u0161anie surov\u00edn, ako je kremenn\u00fd piesok (kremi\u010dit\u00fd piesok), s ropn\u00fdm koksom alebo antracitov\u00fdm uhl\u00edm v elektrickej obl\u00fakovej peci zahriatej na pribli\u017ene 2600 \u00b0C. V r\u00e1mci tohto procesu zahrievania sa oxid kremi\u010dit\u00fd (SiO2) redukuje a men\u00ed na SiC a in\u00e9 zl\u00fa\u010deniny naz\u00fdvan\u00e9 metalurgick\u00e9 kremi\u010ditany, ktor\u00e9 sa nesk\u00f4r op\u00e4\u0165 rozomel\u00fa na \u010dierny alebo zelen\u00fd karbid krem\u00edka v z\u00e1vislosti od ich kvality.<\/p>\n
V\u00fdroba karbidu krem\u00edka touto technikou poskytuje vysok\u00fd v\u00fd\u0165a\u017eok, pri\u010dom sa z jednej vs\u00e1dzky do pece vyrob\u00ed a\u017e 11,3 tony \u010dierneho karbidu krem\u00edka. Vy\u0161\u0161iu \u010distotu SiC v\u0161ak mo\u017eno z\u00edska\u0165 drah\u0161\u00edmi met\u00f3dami, ako je napr\u00edklad Lelyho proces.<\/p>\n
Karbid krem\u00edka sa vyskytuje v r\u00f4znych polymorfoch alebo form\u00e1ch, pri\u010dom ka\u017ed\u00e1 z nich m\u00e1 odli\u0161n\u00e9 charakteristiky a vlastnosti. Napr\u00edklad karbid krem\u00edka alfa (a-SiC) m\u00e1 hexagon\u00e1lnu kry\u0161t\u00e1lov\u00fa \u0161trukt\u00faru podobn\u00fa wurtzitu, zatia\u013e \u010do beta modifikovan\u00fd b-SiC obsahuje kry\u0161t\u00e1lov\u00e9 \u0161trukt\u00fary zinku blende podobn\u00e9 diamantu.<\/p>\n
V\u0161etky formy karbidu krem\u00edka maj\u00fa bez oh\u013eadu na svoj polymorf podobn\u00fa vrstevnat\u00fa \u0161trukt\u00faru obsahuj\u00facu at\u00f3my krem\u00edka a uhl\u00edka viazan\u00e9 do tetraedrickej konfigur\u00e1cie. SiC sa od karbidu b\u00f3ru odli\u0161uje t\u00fdm, \u017ee na ka\u017ed\u00fd at\u00f3m krem\u00edka v jeho \u0161trukt\u00fare pripadaj\u00fa tri at\u00f3my uhl\u00edka - na rozdiel od jeho koso\u0161tvorcovej \u0161trukt\u00fary, ktor\u00e1 d\u00e1va karbidu b\u00f3ru lep\u0161ie mechanick\u00e9 vlastnosti a v\u00e4\u010d\u0161iu komer\u010dn\u00fa \u017eivotaschopnos\u0165; preto sa a-SiC p\u00fd\u0161il lep\u0161\u00edmi mechanick\u00fdmi vlastnos\u0165ami a stal sa dominantn\u00fdm, k\u00fdm nepri\u0161iel b-SiC, ktor\u00fd je rozpustnej\u0161\u00ed.<\/p>\n
Karbid krem\u00edka je extr\u00e9mne tvrd\u00fd, kry\u0161talick\u00fd materi\u00e1l s mnoh\u00fdmi priemyseln\u00fdmi aplik\u00e1ciami. Najm\u00e4 sa be\u017ene pou\u017e\u00edva ako br\u00fasivo v br\u00fasnych kot\u00fa\u010doch, rezn\u00fdch n\u00e1strojoch a br\u00fasnych papieroch v\u010faka svojej ve\u013emi vysokej pevnosti a tvrdosti; medzi jeho \u010fal\u0161ie pou\u017eitia v\u0161ak patria elektrick\u00e9 izol\u00e1tory, \u017eiaruvzdorn\u00e9 materi\u00e1ly a keramika - v\u010faka svojej n\u00edzkej tepelnej roz\u0165a\u017enosti je ide\u00e1lnym materi\u00e1lom na pou\u017eitie v prostred\u00ed s vysokou teplotou - hoci sa \u010dasto pokr\u00fdva oxidom hlinit\u00fdm, aby sa e\u0161te viac pred\u013a\u017eila jeho \u017eivotnos\u0165.<\/p>\n
V\u00fdroba karbidu krem\u00edka sa za\u010d\u00edna najprv zahrievan\u00edm surov\u00e9ho oxidu kremi\u010dit\u00e9ho a uhl\u00edka v elektrickej peci, a\u017e k\u00fdm sa ich zl\u00fa\u010deniny nezl\u00fa\u010dia a nevznikne oxid kremi\u010dit\u00fd a plynn\u00fd oxid uho\u013enat\u00fd, potom nasleduje nieko\u013ekod\u0148ov\u00e9 su\u0161enie v inertnej atmosf\u00e9re pri teplot\u00e1ch v rozmedz\u00ed 1 400 - 2 700 stup\u0148ov Celzia - to umo\u017e\u0148uje \u00fa\u010dinn\u00e9 odstr\u00e1nenie ne\u010dist\u00f4t a vznik\u00e1 takmer \u010dist\u00fd ingot karbidu krem\u00edka.<\/p>\n
Kvalifikovan\u00ed pracovn\u00edci potom tento ingot triedia a klasifikuj\u00fa na r\u00f4zne ve\u013ekosti, tvary a chemick\u00e9 zlo\u017eenie, ktor\u00e9 vyhovuj\u00fa r\u00f4znym aplik\u00e1ci\u00e1m. Po vytrieden\u00ed a klasifik\u00e1cii kvalifikovan\u00fdmi pracovn\u00edkmi sa m\u00f4\u017ee \u010falej spracova\u0165 na pou\u017eitie v priemyseln\u00fdch odvetviach, ako s\u00fa brusiv\u00e1, metalurgia a \u017eiaruvzdorn\u00e9 materi\u00e1ly, ako aj na v\u00fdrobu dopantov do polovodi\u010dov\u00fdch v\u00fdrobkov, ak sa do nich pridaj\u00fa dopanty.<\/p>\n
Dopanty pridan\u00e9 do ingotu m\u00f4\u017eu vytvori\u0165 viacero polytypov s odli\u0161n\u00fdmi fyzik\u00e1lnymi a elektrick\u00fdmi vlastnos\u0165ami. B\u00f3r a hlin\u00edk vytvoria z krem\u00edka polovodi\u010d typu p, zatia\u013e \u010do dus\u00edk a fosfor vytvoria polovodi\u010d typu n.<\/p>\n
V\u00fdroba \u010dist\u00e9ho karbidu krem\u00edka si vy\u017eaduje zlo\u017eit\u00fd a d\u00f4kladn\u00fd proces, ktor\u00fd si vy\u017eaduje prec\u00edznu pozornos\u0165 pri ka\u017edom kroku. \u017diaromateri\u00e1ly vyr\u00e1ban\u00e9 z karbidu krem\u00edka na pou\u017eitie v br\u00fasnom, metalurgickom a \u017eiaruvzdornom priemysle maj\u00fa \u010dasto jedine\u010dn\u00e9 \u0161pecifik\u00e1cie, ako s\u00fa ve\u013ekosti z\u0155n, typy spojiva, \u00farove\u0148 \u010distoty, \u00farove\u0148 hustoty a po\u017eiadavky na p\u00f3rovitos\u0165. N\u00e1\u0161 t\u00edm spolo\u010dnosti Washington Mills bude ochotne spolupracova\u0165 so z\u00e1kazn\u00edkmi, aby pochopil ich individu\u00e1lne po\u017eiadavky a z\u00e1rove\u0148 presk\u00famal v\u0161etky mo\u017enosti s produktmi CARBOREX.<\/p>\n
S karbidom krem\u00edka sa m\u00f4\u017ee \u0165a\u017eko pracova\u0165 a br\u00fasi\u0165, \u010do si vy\u017eaduje diamantov\u00e9 alebo ultrazvukov\u00e9 n\u00e1stroje na rezanie alebo br\u00fasenie. Okrem toho si jeho jemn\u00fd povrch vy\u017eaduje opatrn\u00e9 zaobch\u00e1dzanie, aby sa predi\u0161lo odlupovaniu alebo od\u0161tiepeniu; ke\u010f\u017ee jeho odolnos\u0165 mu umo\u017e\u0148uje dobre odol\u00e1va\u0165 ve\u013emi vysok\u00fdm teplot\u00e1m v peciach alebo su\u0161iar\u0148ach.<\/p>\n
Achesonov proces. Karbid krem\u00edka mo\u017eno vytvori\u0165 t\u00fdmto procesom zmie\u0161an\u00edm kremi\u010dit\u00e9ho piesku s uhl\u00edkov\u00fdm pr\u00e1\u0161kov\u00fdm koksom, aby sa vytvorila zelen\u00e1 alebo \u010dierna pevn\u00e1 l\u00e1tka, ktor\u00e1 sa potom m\u00f4\u017ee rozomlie\u0165 na jemn\u00fd pr\u00e1\u0161ok a zmie\u0161a\u0165 s \u010fal\u0161\u00edmi zlo\u017ekami, aby sa vytvoril plastifik\u00e1tor, ktor\u00fd umo\u017en\u00ed spojenie at\u00f3mov oxidu kremi\u010dit\u00e9ho a uhl\u00edka a potom sa formuje pomocou foriem pred infiltr\u00e1ciou tekut\u00e9ho krem\u00edka, aby sa vytvoril reak\u010dne spojen\u00fd materi\u00e1l alebo spekan\u00fd materi\u00e1l.<\/p>\n
Spekan\u00fd karbid krem\u00edka sa m\u00f4\u017ee pochv\u00e1li\u0165 vy\u0161\u0161ou \u010distotou ako reak\u010dne sp\u00e1jan\u00fd, \u013eah\u0161ie sa obr\u00e1ba a tvaruje a m\u00e1 vynikaj\u00facu odolnos\u0165 proti kor\u00f3zii, opotrebovaniu a tepeln\u00fdm \u0161okom - je schopn\u00fd odola\u0165 teplot\u00e1m 1600 \u00b0C bez toho, aby pod\u013eahol oxid\u00e1cii alebo chemick\u00e9mu p\u00f4sobeniu. V\u010faka t\u00fdmto vlastnostiam sa pou\u017e\u00edva v \u0161irokej \u0161k\u00e1le priemyseln\u00fdch aplik\u00e1ci\u00ed.<\/p>\n
Technol\u00f3gia spekania sa vo ve\u013ekej miere pou\u017e\u00edva v pokro\u010dil\u00fdch elektronick\u00fdch aplik\u00e1ci\u00e1ch. Na tento \u00fa\u010del sa v procese spekania vyr\u00e1baj\u00fa ve\u013ek\u00e9 monokry\u0161t\u00e1lov\u00e9 gu\u013e\u00f4\u010dky, ktor\u00e9 sa potom re\u017e\u00fa na do\u0161ti\u010dky na pou\u017eitie v polovodi\u010dov\u00fdch zariadeniach. Niekedy sa \u010dist\u00e9 materi\u00e1ly m\u00f4\u017eu mie\u0161a\u0165 s b\u00f3rom alebo hlin\u00edkom, aby sa zv\u00fd\u0161ila tvrdos\u0165 a kalite\u013enos\u0165.<\/p>\n
Spekan\u00edm mo\u017eno vytvori\u0165 vysokopevnostn\u00fa keramiku, ktor\u00e1 je odoln\u00e1 vo\u010di praskaniu. Tento typ keramiky je nielen odoln\u00fd vo\u010di vysok\u00fdm teplot\u00e1m, ale je aj vysoko \u017eiaruvzdorn\u00fd vo\u010di chemik\u00e1li\u00e1m, ako s\u00fa kyseliny s\u00edrov\u00e1 a fluorovod\u00edkov\u00e1; odtia\u013e poch\u00e1dza n\u00e1zov spekan\u00fd a-SiC. Tvrdos\u0165, tuhos\u0165, tepeln\u00e1 vodivos\u0165 a tvrdos\u0165 karbidu krem\u00edka ho robia \u017eiaducim aj ako materi\u00e1l zrkadiel astronomick\u00fdch teleskopov; na rozdiel od mnoh\u00fdch in\u00fdch materi\u00e1lov zrkadiel zost\u00e1va stabiln\u00fd po\u010das teplotn\u00fdch zmien bez toho, aby sa deformoval pod vlastnou v\u00e1hou, \u010do mu umo\u017e\u0148uje nahradi\u0165 sklo v r\u00f4znych modeloch teleskopov od mal\u00fdch ru\u010dn\u00fdch modelov a\u017e po obrovsk\u00e9 vesm\u00edrne observat\u00f3ri\u00e1.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide (SiC) is a hard chemical compound comprised of silicon and carbon, found naturally as moissanite gemstone and produced mass-scale for use in abrasives, metallurgical applications and refractories. SiC is ideal for fire bricks and other refractory products due to its resistance to high temperature and thermal shock, its semi-conductive nature, and atomic structure […]<\/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-477","post","type-post","status-publish","format-standard","hentry","category-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/477","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/comments?post=477"}],"version-history":[{"count":1,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/477\/revisions"}],"predecessor-version":[{"id":478,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/477\/revisions\/478"}],"wp:attachment":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/media?parent=477"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/categories?post=477"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/tags?post=477"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}