Ljudje imenujejo heksagonalni borov nitrid \u00bbbeli grafit\u00ab, ker je kristalna struktura enaka: nalo\u017eene plo\u0161\u010de, ki se med seboj stri\u017eejo. Zato se suh film iz h-BN na dotik zdi spolzek. Primerjava pa ni ve\u010d uporabna, takoj ko pride do vro\u010dine, oksidacije ali elektri\u010dnega toka. Grafit je prevodnik in se na zraku za\u010dne oksidirati pri temperaturi okoli 500\u2013600 \u00b0C. Heksagonalni BN ostane izolativen, na zraku pa kot prakti\u010dno okno oksidacije obravnavamo temperaturo 900\u20131000 \u00b0C. V du\u0161iku ali vakuumu ta temperatura zna\u0161a veliko ve\u010d, proti 2000 \u00b0C in ve\u010d. To je razlog, da predpi\u0161emo BN namesto ogljika, kadar mora premaz prenesti vro\u010dino in ostati dielektri\u010den.<\/p>\n
Pra\u0161ek, ki ga prodajamo za premaze, je obi\u010dajno plo\u0161\u010dat h-BN, pogosto v velikosti nekaj mikronov, v\u010dasih pa tudi finej\u0161i za gladko nana\u0161anje s pr\u0161enjem. Ko se zme\u0161a z vezivom, postane lo\u010dilna barva za kalupe, matrice, livarske lonce in cevi za termoelemente. Pri taljenem aluminiju je klju\u010dnega pomena omo\u010denje. Aluminij le\u017ei na borovem nitridu z visokim kontaktnim kotom \u2013 okoli 160\u00b0 do 900\u00b0C v objavljenih raziskavah s fiksno kapljico \u2013, zato se kovina ne oprijema keramike tako, kot se oprijema aluminijevega oksida ali umazane jeklene podlage. Odstranite plast, nalijte, odstranite ostanke. Tudi grafit lahko deluje kot lo\u010dilno sredstvo, dokler se ne za\u017ege in pusti ogljikovo made\u017e ali vdolbino. BN pusti bel film. Delavnice, ki prevle\u010dejo odto\u010dne kanale in potopne cevi, opazijo razliko \u017ee po enem tednu, ne \u0161ele po laboratorijskem predavanju.<\/p>\n
Toplotna prevodnost je v monokristalu zadovoljiva in mo\u010dno anizotropna. Pri vro\u010de stisnjenem delu ali prevleki dobimo bolj povpre\u010dno vrednost, ki je \u0161e vedno dovolj visoka, da se keramika iz borovega nitrida uporablja tam, kjer se mora toplota prena\u0161ati, tok pa ne: razporevalniki toplote, prevleke za utrjevanje, visokotemperaturna elektri\u010dna izolacija. Ta kombinacija \u2013 prevajanje toplote in blokiranje toka \u2013 ni lastnost grafita. Grafit deluje v obeh smereh, kar je za izolator neprimerno.<\/p>\n
Kubi\u010dni BN je druga\u010den material. Enaki elementi, diamantna kristalna mre\u017ea, trdota kot pri rezalnih orodjih. Ne naro\u010dajte c-BN, \u010de ste imeli v mislih protilepljiv premaz, in ne pri\u010dakujte, da boste z h-BN prahom, primernim za barvanje, obdelovali jeklo. Pirolitski BN je spet druga vrsta: CVD plo\u0161\u010de in lonci za delo s polprevodniki, zelo \u010disti, zelo dragi. Ve\u010dina na\u0161ih industrijskih naro\u010dil \u0161e vedno zajema heksagonalni prah in vro\u010de stisnjene oblike.<\/p>\n
h-BN pri nizkih temperaturah ni \u010dude\u017een. Pri temperaturah pod pribli\u017eno 600 \u00b0C ima grafit pogosto ni\u017eji koeficient trenja. BN prevzame vodstvo, ko se grafit za\u010dne oksidirati. Vlaga, olje in debel, lu\u0161\u010de\u010d se sloj uni\u010dijo dober prah. Nanesite tanko, enakomerno in suho plast ter jo ponovno nanesite, ko bela barva izgine. \u010ce je talina aluminij ali magnezij in mora orodje ostati \u010disto ter elektri\u010dno neaktivno, je heksagonalni borov nitrid mazivo, ki ostane na mestu tudi potem, ko se grafit spremeni v 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\/sl\/wp-json\/wp\/v2\/posts\/337"}],"collection":[{"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/comments?post=337"}],"version-history":[{"count":1,"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/posts\/337\/revisions"}],"predecessor-version":[{"id":338,"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/posts\/337\/revisions\/338"}],"wp:attachment":[{"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/media?parent=337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/categories?post=337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/boronnitrideceramic.com\/sl\/wp-json\/wp\/v2\/tags?post=337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}