\u013dudia naz\u00fdvaj\u00fa hexagon\u00e1lny nitrid b\u00f3ru \u201ebielym grafitom\u201c, preto\u017ee kry\u0161t\u00e1lov\u00e1 \u0161trukt\u00fara je zalo\u017een\u00e1 na rovnakom princ\u00edpe: na vrstven\u00fdch platni\u010dk\u00e1ch, ktor\u00e9 sa vz\u00e1jomne \u0161m\u00fdkaj\u00fa. Preto sa such\u00e1 vrstva h-BN na dotyk jav\u00ed ako k\u013azav\u00e1. Toto porovnanie v\u0161ak str\u00e1ca zmysel hne\u010f, ako sa materi\u00e1l zahreje, doch\u00e1dza k oxid\u00e1cii alebo je pod nap\u00e4t\u00edm. Grafit je vodi\u010d a na vzduchu sa za\u010d\u00edna oxidova\u0165 pri teplote okolo 500\u2013600 \u00b0C. Hexagon\u00e1lny BN si zachov\u00e1va izola\u010dn\u00e9 vlastnosti a na vzduchu pova\u017eujeme za praktick\u00e9 oxida\u010dn\u00e9 rozmedzie teploty 900\u20131000 \u00b0C. V dus\u00edku alebo vo v\u00e1kuu je t\u00e1to teplota ove\u013ea vy\u0161\u0161ia, smerom k 2000 \u00b0C a viac. To je d\u00f4vod, pre\u010do \u0161pecifikujeme BN namiesto uhl\u00edka, ke\u010f mus\u00ed povlak odola\u0165 teplu a zosta\u0165 dielektrick\u00fd.<\/p>\n
Pr\u00e1\u0161ok, ktor\u00fd pred\u00e1vame na povrchov\u00e9 \u00fapravy, je zvy\u010dajne h-BN v podobe do\u0161ti\u010diek, \u010dasto v rozmedz\u00ed nieko\u013ek\u00fdch mikr\u00f3nov, niekedy aj jemnej\u0161\u00ed pre hladk\u00e9 nan\u00e1\u0161anie striekan\u00edm. Po zmie\u0161an\u00ed s pojivom sa z neho st\u00e1va odde\u013eovacia farba pre formy, lisovacie n\u00e1stroje, panvice a r\u00farky termo\u010dl\u00e1nkov. U\u017eito\u010dn\u00fdm trikom pri pr\u00e1ci s roztaven\u00fdm hlin\u00edkom je zm\u00e1\u010danie. Hlin\u00edk le\u017e\u00ed na nitride b\u00f3ru s vysok\u00fdm kontaktn\u00fdm uhlom \u2013 pribli\u017ene 160\u00b0 a\u017e do 900\u00b0C pod\u013ea publikovan\u00fdch v\u00fdsledkov experimentov s nehybnou kvapkou \u2013 tak\u017ee kov sa nepri\u013ene k keramike tak, ako sa pri\u013ene k oxidu hlinit\u00e9mu alebo k zne\u010distenej oce\u013eovej podlo\u017eke. Zoberte vrstvu, nalejte, odstr\u00e1\u0148te zvy\u0161ky. Aj grafit m\u00f4\u017ee p\u00f4sobi\u0165 ako odde\u013eova\u010d, k\u00fdm sa nesp\u00e1li a nezanech\u00e1 uhl\u00edkov\u00fa \u0161kvrnu alebo jamku. BN zanech\u00e1va biely film. Dielne, ktor\u00e9 povlakuj\u00fa \u017e\u013eaby a ponorn\u00e9 r\u00farky, si v\u0161imn\u00fa rozdiel u\u017e po t\u00fd\u017edni, nie a\u017e po predn\u00e1\u0161ke v laborat\u00f3riu.<\/p>\n
Tepeln\u00e1 vodivos\u0165 je uspokojiv\u00e1 a v monokry\u0161t\u00e1li v\u00fdrazne anizotropn\u00e1. V diele lisovanom za tepla alebo v povlaku sa dosahuje sk\u00f4r priemern\u00e1 hodnota, ktor\u00e1 je v\u0161ak st\u00e1le dostato\u010dne vysok\u00e1 na to, aby sa keramika z nitridu b\u00f3ru pou\u017e\u00edvala tam, kde sa mus\u00ed pren\u00e1\u0161a\u0165 teplo, ale nie pr\u00fad: rozv\u00e1dza\u010de tepla, povlaky na stabiliz\u00e1ciu, vysokoteplotn\u00e1 elektrick\u00e1 izol\u00e1cia. T\u00e1to kombin\u00e1cia \u2013 vedenie tepla a blokovanie pr\u00fadu \u2013 nie je vlastnos\u0165ou grafitu. Grafit rob\u00ed oboje, av\u0161ak v smere, ktor\u00fd je pre izolant nevhodn\u00fd.<\/p>\n
Kubick\u00fd BN je odli\u0161n\u00fd materi\u00e1l. Tie ist\u00e9 prvky, mrie\u017eka podobn\u00e1 diamantu, tvrdos\u0165 ako u rezac\u00edch n\u00e1strojov. Neobjedn\u00e1vajte si c-BN, ak m\u00e1te na mysli uvo\u013e\u0148ovac\u00ed povlak, a neo\u010dak\u00e1vajte, \u017ee pr\u00e1\u0161ok h-BN v kvalite farby bude vhodn\u00fd na obr\u00e1banie ocele. Pyrolytick\u00fd BN je zase in\u00e1 trieda: CVD dosky a t\u00e9gliky pre pr\u00e1cu s polovodi\u010dmi, ve\u013emi \u010dist\u00e9, ve\u013emi drah\u00e9. V\u00e4\u010d\u0161ina na\u0161ich priemyseln\u00fdch objedn\u00e1vok sa st\u00e1le t\u00fdka hexagon\u00e1lneho pr\u00e1\u0161ku a tvarov lisovan\u00fdch za tepla.<\/p>\n
h-BN nie je pri n\u00edzkych teplot\u00e1ch \u017eiadnym z\u00e1zrakom. Pri teplot\u00e1ch pod pribli\u017ene 600 \u00b0C m\u00e1 grafit \u010dasto ni\u017e\u0161\u00ed koeficient trenia. BN sa dost\u00e1va do vedenia, akon\u00e1hle grafit za\u010dne oxidova\u0165. Vlhkos\u0165, olej a hrub\u00e1, odlupuj\u00faca sa vrstva zni\u010dia kvalitn\u00fd pr\u00e1\u0161ok. Nan\u00e1\u0161ajte tenk\u00fa, rovnomern\u00fa a such\u00fa vrstvu a v pr\u00edpade potreby ju naneste znovu, ke\u010f biela farba zmizne. Ak sa tav\u00ed hlin\u00edk alebo hor\u010d\u00edk a n\u00e1stroj mus\u00ed zosta\u0165 \u010dist\u00fd a bez elektrick\u00e9ho ru\u0161enia, hexagon\u00e1lny nitrid b\u00f3ru je mazivo, ktor\u00e9 zostane na mieste aj po tom, \u010do sa grafit premen\u00ed na CO\u2082.<\/p>","protected":false},"excerpt":{"rendered":"
Hexagonal Boron Nitride Is Graphite That Does Not Conduct and Does Not Burn Off at 600\u00b0C People call hexagonal boron […]<\/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 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":""}},"ngg_post_thumbnail":0,"footnotes":""},"categories":[4],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/posts\/337"}],"collection":[{"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/comments?post=337"}],"version-history":[{"count":1,"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/posts\/337\/revisions"}],"predecessor-version":[{"id":338,"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/posts\/337\/revisions\/338"}],"wp:attachment":[{"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/media?parent=337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/categories?post=337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/boronnitrideceramic.com\/sk\/wp-json\/wp\/v2\/tags?post=337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}