{"id":716,"date":"2026-10-11T21:20:22","date_gmt":"2026-10-11T13:20:22","guid":{"rendered":"https:\/\/siliconcarbide.net\/?p=716"},"modified":"2026-10-11T21:20:22","modified_gmt":"2026-10-11T13:20:22","slug":"preco-karbid-kremika-spojeny-nitridom-straca-pevnost-po-8-az-12-mesiacoch","status":"publish","type":"post","link":"https:\/\/siliconcarbide.net\/sk\/why-nitride-bonded-silicon-carbide-lose-strength-after-8-12-months\/","title":{"rendered":"Pre\u010do karbid krem\u00edka spojen\u00fd nitridom str\u00e1ca pevnos\u0165 po 8\u201312 mesiacoch"},"content":{"rendered":"

Pre\u010do karbid krem\u00edka spojen\u00fd nitridom str\u00e1ca pevnos\u0165 po 8\u201312 mesiacoch v oxida\u010dn\u00fdch atmosf\u00e9rach<\/strong><\/h1>\n

Dvan\u00e1s\u0165 rokov som sa zaoberal zariadeniami pracuj\u00facimi pri vysok\u00fdch teplot\u00e1ch v \u0160anghaji a v okolit\u00fdch keramick\u00fdch a hutn\u00edckych z\u00e1vodoch. Jedn\u00fdm z naj\u010dastej\u0161\u00edch probl\u00e9mov, s ktor\u00fdmi sa stret\u00e1vam pri karbide krem\u00edka spojenom nitridom, je to, \u017ee police, dosky a podlo\u017eky v peci vyzeraj\u00fa pevne pri vlo\u017een\u00ed do pece, av\u0161ak po nieko\u013ek\u00fdch mesiacoch be\u017enej prev\u00e1dzky za\u010dn\u00fa praska\u0165 alebo sa preh\u00fdba\u0165 pod za\u0165a\u017een\u00edm, ktor\u00e9 predt\u00fdm zvl\u00e1dali bez probl\u00e9mov. V\u00e4\u010d\u0161ina prev\u00e1dzkovate\u013eov predpoklad\u00e1, \u017ee sa materi\u00e1l jednoducho \u201copotreboval\u201d alebo \u017ee vypa\u013eovac\u00ed cyklus bol pr\u00edli\u0161 agres\u00edvny. V link\u00e1ch, s ktor\u00fdmi pracujem, je skuto\u010dnou pr\u00ed\u010dinou postupn\u00e1 oxid\u00e1cia f\u00e1zy s nitridov\u00fdm spojivom, akon\u00e1hle je povrch vystaven\u00fd vzduchu pri vysokej teplote.<\/p>\n

Karbid krem\u00edka spojen\u00fd nitridom vyu\u017e\u00edva maticu z nitridu krem\u00edka, ktor\u00e1 dr\u017e\u00ed zrn\u00e1 karbidu krem\u00edka pohromade a dod\u00e1va dielu pevnos\u0165 a odolnos\u0165 vo\u010di tepeln\u00fdm \u0161okom. V reduk\u010dnej alebo neutr\u00e1lnej atmosf\u00e9re zost\u00e1va t\u00e1to v\u00e4zba relat\u00edvne stabiln\u00e1. Akon\u00e1hle pec pracuje s nadbytkom vzduchu \u2013 \u010do je be\u017en\u00e9 pri preru\u0161ovanom vypa\u013eovan\u00ed keramiky alebo pri ur\u010dit\u00fdch cykloch tepeln\u00e9ho spracovania kovov \u2013 kysl\u00edk napad\u00e1 nitrid. Na povrchu a, \u010do je e\u0161te d\u00f4le\u017eitej\u0161ie, na hraniciach z\u0155n sa vytv\u00e1ra tenk\u00e1 vrstva bohat\u00e1 na oxid kremi\u010dit\u00fd. S\u00fa\u010diastka sa nezlom\u00ed n\u00e1hle; postupne str\u00e1ca pevnos\u0165 v ohybe a st\u00e1va sa citlivej\u0161ou na teplotn\u00e9 gradienty. Pravidelne sa stret\u00e1vam s doskami, ktor\u00fdch pevnos\u0165 bola v novom stave v\u00fdrazne nad 40 MPa, ale po 8\u201312 mesiacoch ka\u017edodenn\u00e9ho striedania tepl\u00f4t medzi 1200 \u00b0C a izbovou teplotou klesla na hodnoty v n\u00edzkych 20-tich.<\/p>\n

Praktick\u00fd d\u00f4sledok sa prejavuje dvoma sp\u00f4sobmi. Po prv\u00e9, na policiach vznikaj\u00fa vlasov\u00e9 trhliny, ktor\u00e9 za\u010d\u00ednaj\u00fa na okrajoch alebo v okol\u00ed oporn\u00fdch bodov a n\u00e1sledne sa \u0161\u00edria pod vplyvom vlastnej hmotnosti a za\u0165a\u017eenia tovarom. Po druh\u00e9, efekt\u00edvna nosnos\u0165 kles\u00e1 e\u0161te sk\u00f4r, ako sa objavia vidite\u013en\u00e9 trhliny, tak\u017ee prev\u00e1dzkovatelia bu\u010f zni\u017euj\u00fa po\u010det kusov na polici, alebo akceptuj\u00fa vy\u0161\u0161iu mieru po\u0161kodenia tovaru. V oboch pr\u00edpadoch z\u00e1vod nakoniec vymen\u00ed reg\u00e1ly sk\u00f4r, ako sa predpokladalo v p\u00f4vodnej kalkul\u00e1cii n\u00e1kupu. Z\u00e1vody prev\u00e1dzkuj\u00face kontinu\u00e1lne pos\u00fava\u010de alebo valcov\u00e9 pece s pr\u00edsnej\u0161ou regul\u00e1ciou atmosf\u00e9ry zvy\u010dajne dosahuj\u00fa dlh\u0161iu \u017eivotnos\u0165 pri pou\u017eit\u00ed rovnak\u00e9ho druhu materi\u00e1lu; v pr\u00edpade preru\u0161ovan\u00fdch d\u00e1vkov\u00fdch pec\u00ed, be\u017en\u00fdch v oblasti \u0160anghaja, sa tento probl\u00e9m prejav\u00ed r\u00fdchlej\u0161ie, preto\u017ee pri ka\u017edom ochladen\u00ed sa na hor\u00face povrchy dostane \u010derstv\u00fd vzduch.<\/p>\n

Ke\u010f pova\u017eujete f\u00e1zu viazania za limituj\u00faci faktor, je jasn\u00e9, \u010do vlastne spoma\u013euje degrad\u00e1ciu. Udr\u017eujte maxim\u00e1lnu teplotu a dobu zotrvania pri tejto teplote na najni\u017e\u0161ej \u00farovni, ak\u00fa proces dovo\u013euje; ka\u017ed\u00fdch \u010fal\u0161\u00edch 50 \u00b0C nad 1350 \u00b0C v\u00fdrazne ur\u00fdch\u013euje r\u00fdchlos\u0165 oxid\u00e1cie, ktor\u00fa meriam na vr\u00e1ten\u00fdch dieloch. Ak to kon\u0161trukcia pece dovo\u013euje, kr\u00e1tke preplachovanie alebo mierne reduk\u010dn\u00e1 atmosf\u00e9ra po\u010das udr\u017eovania vysokej teploty zn\u00ed\u017eia parci\u00e1lny tlak kysl\u00edka nato\u013eko, \u017ee sa \u017eivotnos\u0165 pred\u013a\u017ei o nieko\u013eko mesiacov. Rovnako d\u00f4le\u017eit\u00e9 je mechanick\u00e9 za\u0165a\u017eenie. Nitridom spojen\u00e9 SiC, ktor\u00e9 s\u00fa podopren\u00e9 len na koncoch a nes\u00fa \u0165a\u017ek\u00e9, nerovnomern\u00e9 za\u0165a\u017eenie, vyv\u00edjaj\u00fa vy\u0161\u0161ie \u0165ahov\u00e9 nap\u00e4tia na spodnej ploche; akon\u00e1hle je povrch oslaben\u00fd oxid\u00e1ciou, tieto nap\u00e4tia sp\u00f4sobuj\u00fa skor\u0161ie vznik trhl\u00edn. Prechod na trojbodov\u00fa alebo nepretr\u017eit\u00fa oporu, alebo jednoduch\u00e9 zn\u00ed\u017eenie maxim\u00e1lneho za\u0165a\u017eenia na jednu dosku o 15\u201320 %, \u010dasto obnov\u00ed p\u00f4vodn\u00fd interval v\u00fdmeny bez zmeny triedy materi\u00e1lu.<\/p>\n

U vr\u00e1ten\u00fdch dosiek tie\u017e kontrolujem hr\u00fabku oxidovanej vrstvy. Norm\u00e1lny je rovnomern\u00fd svetlosiv\u00fd povrchov\u00fd film s hr\u00fabkou nieko\u013ek\u00fdch stoviek mikr\u00f3nov; miestne silnej\u0161ie okuj\u00ed alebo pr\u00e1\u0161kovanie na okrajoch zvy\u010dajne znamen\u00e1 bu\u010f hor\u00face miesto v peci, alebo dlhodob\u00e9 vystavenie nad odpor\u00fa\u010dan\u00fdm limitom. Z\u00e1vody, ktor\u00e9 zaznamen\u00e1vaj\u00fa hodnoty atmosf\u00e9ry a maxim\u00e1lne za\u0165a\u017eenie pol\u00edc spolu s po\u010dtom cyklov pred vznikom prv\u00fdch trhl\u00edn, m\u00f4\u017eu zvy\u010dajne pred\u013a\u017ei\u0165 priemern\u00fa \u017eivotnos\u0165 z pribli\u017ene 10 mesiacov na 14\u201316 mesiacov pri pou\u017eit\u00ed rovnak\u00e9ho nitridom viazan\u00e9ho SiC. Tie, ktor\u00e9 na\u010falej pou\u017e\u00edvaj\u00fa p\u00f4vodn\u00fd hust\u00fd vzor za\u0165a\u017eenia a atmosf\u00e9ru s pln\u00fdm pr\u00fadom vzduchu, jednoducho vymie\u0148aj\u00fa dosky pod\u013ea krat\u0161ieho a n\u00e1kladnej\u0161ieho harmonogramu a neust\u00e1le sa \u010duduj\u00fa, pre\u010do nov\u00e1 sada nevydr\u017e\u00ed dlh\u0161ie ako t\u00e1 predch\u00e1dzaj\u00faca.<\/p>\n

Samotn\u00fd materi\u00e1l m\u00e1 dlh\u00fa \u017eivotnos\u0165, ak je chr\u00e1nen\u00e1 v\u00e4zbov\u00e1 f\u00e1za. Rozdiel, ktor\u00fd v praxi pozorujem, takmer nikdy nespo\u010d\u00edva v n\u00e1hlej zmene kvality suroviny; ide sk\u00f4r o to, \u010di z\u00e1vod pova\u017euje oxid\u00e1ciu a za\u0165a\u017eenie za riadite\u013en\u00e9 premenn\u00e9, alebo za nevyhnutn\u00e9 r\u00e1mcov\u00e9 podmienky.<\/p>","protected":false},"excerpt":{"rendered":"

Why Nitride Bonded Silicon Carbide Lose Strength After 8\u201312 Months in Oxidizing Atmospheres I\u2019ve spent twelve years dealing with high-temperature equipment around Shanghai and the surrounding ceramics and metallurgy plants. One of the most consistent problems I see with nitride bonded silicon carbide is that the kiln shelves, plates, and setters look solid when they… <\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"off","neve_meta_content_width":70,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","ngg_post_thumbnail":0,"footnotes":""},"categories":[30],"tags":[],"class_list":["post-716","post","type-post","status-publish","format-standard","hentry","category-sic-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/posts\/716","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/comments?post=716"}],"version-history":[{"count":1,"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/posts\/716\/revisions"}],"predecessor-version":[{"id":717,"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/posts\/716\/revisions\/717"}],"wp:attachment":[{"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/media?parent=716"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/categories?post=716"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/siliconcarbide.net\/sk\/wp-json\/wp\/v2\/tags?post=716"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}