Silicon nitride - zoumba zadothi zopangidwa ndi kapangidwe kake zomwe zimagwira ntchito bwino kwambiri

Ma ceramic apadera amatanthauza gulu la ma ceramic omwe ali ndi mawonekedwe apadera a makina, thupi kapena mankhwala, zinthu zopangira zomwe zimagwiritsidwa ntchito ndi ukadaulo wofunikira wopanga zimasiyana kwambiri ndi ma ceramic wamba komanso chitukuko. Malinga ndi mawonekedwe ndi ntchito, ma ceramic apadera amatha kugawidwa m'magulu awiri: ma ceramic omangira ndi ma ceramic ogwirira ntchito. Pakati pawo, ma ceramic omangira amatanthauza ma ceramic omwe angagwiritsidwe ntchito ngati zida zomangira zaukadaulo, zomwe nthawi zambiri zimakhala ndi mphamvu zambiri, kuuma kwambiri, modulus yolimba kwambiri, kukana kutentha kwambiri, kukana kuvala, kukana dzimbiri, kukana okosijeni, kukana kutentha ndi zina.

Pali mitundu yambiri ya zoumba zadothi, ubwino ndi kuipa kwake, ndipo njira yogwiritsira ntchito ubwino ndi kuipa kwake ndi yosiyana, pakati pawo "zoumba zadothi za silicon nitride" chifukwa cha magwiridwe antchito m'mbali zonse, zimadziwika kuti ndi ntchito yabwino kwambiri m'banja la zoumba zadothi, ndipo zili ndi ntchito zambiri.

Ubwino wa silicon nitride ceramics

Silicon nitride (Si3N4) ikhoza kugawidwa m'magulu a covalent bond compounds, ndi [SiN4] 4-tetrahedron ngati gawo lomanga. Malo enieni a maatomu a nayitrogeni ndi silicon amatha kuwoneka kuchokera pachithunzi chili pansipa, silicon ili pakati pa tetrahedron, ndipo malo a ma vertices anayi a tetrahedron amakhala ndi maatomu a nayitrogeni, kenako tetrahedron iliyonse itatu imagawana atomu imodzi, nthawi zonse imafalikira mu malo atatu. Pomaliza, kapangidwe ka netiweki kamapangidwa. Zambiri mwa zinthu za silicon nitride zimagwirizana ndi kapangidwe ka tetrahedron aka.

Pali mapangidwe atatu a silicon nitride okhala ndi ma crystalline, omwe ndi magawo a α, β ndi γ, omwe magawo a α ndi β ndi omwe amagwiritsidwa ntchito kwambiri pa silicon nitride. Chifukwa maatomu a nayitrogeni amaphatikizidwa bwino, silicon nitride ili ndi mphamvu yabwino, kuuma kwambiri komanso kukana kutentha kwambiri, ndipo kuuma kwake kumatha kufika HRA91 ~ 93; Kulimba kwabwino kwa kutentha, kumatha kupirira kutentha kwakukulu kwa 1300 ~ 1400℃; Kuyankha pang'ono kwa mankhwala ndi zinthu za kaboni ndi zitsulo kumabweretsa kukhudzika kochepa; Imadzipaka yokha ndipo motero imakana kuvala; Kukana dzimbiri ndi kwamphamvu, kuwonjezera pa hydrofluoric acid, sichitapo kanthu ndi ma acid ena osapangidwa, kutentha kwakukulu kumakhalanso ndi kukana kwa okosijeni; Imakhalanso ndi kukana kwabwino kwa kutentha, kuzizira kwambiri mumlengalenga kenako kutentha kwakukulu sikungasweke; Kuyenda kwa silicon nitride ceramics kumachepa kutentha kwambiri, ndipo kusintha pang'onopang'ono kwa pulasitiki kumakhala kochepa chifukwa cha kutentha kwakukulu ndi katundu wokhazikika.

Kuphatikiza apo, ma ceramic a silicon nitride alinso ndi mphamvu zapadera, mawonekedwe apadera, kutentha kwakukulu, mphamvu zamagetsi zabwino komanso zabwino zina, kotero ali ndi phindu lapadera logwiritsidwa ntchito m'malo ovuta kwambiri monga kutentha kwambiri, liwiro lalikulu, zowononga zamphamvu, ndipo amaonedwa kuti ndi chimodzi mwa zipangizo zabwino kwambiri zopangira ndi kugwiritsa ntchito ma ceramic, ndipo nthawi zambiri amakhala chisankho choyamba m'mapulogalamu ambiri omwe amafunika kuyesedwa.