Silicon nitride - zoumba za ceramic zomwe zimagwira ntchito bwino kwambiri

Zadothi zapadera zimatanthawuza gulu lazoumba zomwe zimakhala ndi makina apadera, thupi kapena mankhwala, zipangizo zomwe zimagwiritsidwa ntchito ndi teknoloji yopangira zofunikira ndizosiyana kwambiri ndi zoumba ndi chitukuko. Malinga ndi mawonekedwe ndi ntchito, zida zadothi zapadera zitha kugawidwa m'magulu awiri: zoumba ndi ziwiya zogwirira ntchito. Pakati pawo, zoumba zadothi zimatanthawuza za ceramics zomwe zingagwiritsidwe ntchito ngati zida zomangira zomangamanga, zomwe nthawi zambiri zimakhala ndi mphamvu zambiri, kuuma kwakukulu, modulus zotanuka kwambiri, kukana kutentha, kukana kuvala, kukana dzimbiri, kukana makutidwe ndi okosijeni, kukana kugwedezeka kwamafuta ndi zina.

Pali mitundu yambiri ya zoumba zoumba, ubwino ndi kuipa kwake, ndipo kagwiritsidwe ntchito ka ubwino ndi kuipa kwake ndi kosiyana, pakati pawo "silicon nitride ceramics" chifukwa chakuchita bwino m'mbali zonse, imadziwika kuti ndiyo njira yabwino kwambiri yolumikizirana. banja la ceramics structural, ndipo lili ndi ntchito zosiyanasiyana.

Ubwino wa silicon nitride ceramics

Silicon nitride (Si3N4) ikhoza kugawidwa kukhala covalent bond compounds, ndi [SiN4] 4-tetrahedron monga gawo la zomangamanga. Maudindo enieni a maatomu a nayitrogeni ndi silicon amatha kuwoneka kuchokera pazithunzi pansipa, silicon ili pakatikati pa tetrahedron, ndipo malo a ma vertices anayi a tetrahedron amakhala ndi maatomu a nayitrogeni, ndiyeno ma tetrahedron atatu aliwonse amagawana atomu imodzi, nthawi zonse. kufalikira mu danga la mbali zitatu. Pomaliza, dongosolo la maukonde limapangidwa. Zambiri mwazinthu za silicon nitride zimagwirizana ndi mawonekedwe a tetrahedral.

Pali mitundu itatu ya crystalline ya silicon nitride, yomwe ndi α, β ndi γ magawo, omwe α ndi β magawo ndi mitundu yambiri ya silicon nitride. Chifukwa maatomu a nayitrogeni amalumikizana kwambiri, silicon nitride ili ndi mphamvu zabwino kwambiri, kuuma kwakukulu komanso kukana kutentha kwambiri, ndipo kuuma kumatha kufika HRA91 ~ 93; Good matenthedwe kuuma, akhoza kupirira kutentha kwa 1300 ~ 1400 ℃; Kachitidwe kakang'ono ka mankhwala ndi carbon ndi zitsulo zinthu kumabweretsa otsika mikangano coefficient; Imadzipaka mafuta paokha motero imalimbana ndi kuvala; Kukana kwa dzimbiri ndi kolimba, kuwonjezera pa hydrofluoric acid, sikuchita ndi ma inorganic acid, kutentha kwakukulu kumakhalanso kukana kwa okosijeni; Ilinso ndi kukana kwamphamvu kwamafuta, kuziziritsa kwakuthwa mumlengalenga kenako Kutentha kwakuthwa sikungagwe; Kukwera kwa silicon nitride ceramics kumachepa kutentha kwambiri, ndipo kupindika kwa pulasitiki pang'onopang'ono kumakhala kochepa chifukwa cha kutentha kwakukulu ndi katundu wokhazikika.

Kuphatikiza apo, silicon nitride ceramics ilinso ndi mphamvu zenizeni zenizeni, mawonekedwe apamwamba kwambiri, matenthedwe apamwamba kwambiri, zinthu zabwino kwambiri zamagetsi ndi zabwino zina, chifukwa chake imakhala ndi phindu lapadera m'malo owopsa monga kutentha kwambiri, kuthamanga kwambiri, media zowononga kwambiri, ndi zina zambiri. Imawerengedwa kuti ndi imodzi mwazinthu zodalirika kwambiri zama ceramic zopangira chitukuko ndikugwiritsa ntchito, ndipo nthawi zambiri zimakhala chisankho choyamba pamapulogalamu ambiri omwe amafunikira kuyesedwa.