Silicon nitride (Si₃N₄) yog cov khoom siv ntau yam thiab thev naus laus zis tseem ceeb nrog cov qauv siv lead ua nyuaj uas nthuav tawm cov khoom tshwj xeeb, ua rau nws muaj txiaj ntsig hauv ntau yam kev siv, tshwj xeeb hauv thaj av ntawm ceramics thiab cov khoom siv siab heev. Ob theem ntawm silicon nitride feem ntau yog -Si₃N₄ thiab -Si₃N₄. Cov theem no nthuav tawm cov qauv siv lead ua sib txawv, cuam tshuam rau lawv cov khoom siv hluav taws xob, thermal, thiab hluav taws xob.
- Si₃N₄ (Hexagonal Silicon Nitride)
1. Crystal Structure
Cov-theem ntawm silicon nitride nta ib hexagonal siv lead ua qauv (hP los yog rhombohedral). Nyob rau hauv cov qauv no, silicon atoms yog tetrahedrally kev koom tes rau nitrogen atoms, tsim ib tug peb-dimensional network. Lub hexagonal kaw-packed kev npaj ntawm nitrogen atoms nrog silicon atoms nyob octahedral qhov chaw characterizes theem no.
2. Unit Cell
Chav tsev ntawm tes yog hexagonal, feem ntau muaj ob hom qauv. Qhov no hexagonal symmetry txhais lub zuag qhia tag nrho cov qauv thiab pab rau cov anisotropic zog ntawm -Si₃N₄.
3. Kev sib koom tes
Kev sib koom ua ke ntawm tetrahedral ntawm silicon thiab nitrogen atoms tsim kom muaj zog thiab sib cuam tshuam lattice. Cov qauv no suav nrog kev ua haujlwm siab thiab cov khoom siv zoo heev ntawm -Si₃N₄, ua rau nws tsim nyog rau kev thov xws li cov cuab yeej txiav thiab cov kabmob.
4. Khoom
-Si₃N₄ nthuav tawm tshwj xeeb hardness, hnav tsis kam, thiab thermal stability. Nws cov khoom ua rau nws yog tus neeg sib tw zoo tshaj plaws rau kev ua haujlwm siab ceramics siv nyob rau hauv ib puag ncig hnyav, xws li cov uas tau ntsib hauv kev tsim khoom thiab cov txheej txheem machining.
-Si₃N₄ (Cubic lossis Hexagonal Silicon Nitride)
1. Crystal Structure
Cov-theem ntawm silicon nitride tuaj yeem muaj nyob rau hauv ib lub cubic (cP) lossis hexagonal qauv. Zoo ib yam li-theem, silicon atoms yog tetrahedrally ua haujlwm rau nitrogen atoms. Txawm li cas los xij, qhov kev npaj yog cubic lossis hexagonal, nyob ntawm cov xwm txheej tshwj xeeb.
2. Unit Cell
Chav tsev cell yog cubic, feem ntau muaj yim tus qauv qauv. Cov chav tsev loj dua no ua rau muaj qhov sib txawv ntawm qhov ntom ntom thiab ruaj khov ntawm cov theem thiab theem.
3. Kev sib koom tes
Thaum tuav tswj kev sib koom tes tetrahedral, lub cubic lossis hexagonal npaj muab cov khoom tshwj xeeb rau -Si₃N₄. Nws yog metastable ntawm qhov kub thiab txias thiab nthuav tawm nthuav hluav taws xob thiab thermal yam ntxwv.
4. Khoom
-Si₃N₄ muaj peev xwm siv nyob rau hauv high-temperature ceramics thiab refractories. Nws qhov xwm txheej metastable ua rau nws muaj kev txaus siab rau kev tsim cov khoom tshiab nrog cov khoom tsim nyog.
Hauv kev xaus, cov qauv siv lead ua ntawm silicon nitride plays lub luag haujlwm tseem ceeb hauv kev txiav txim siab nws cov khoom thiab kev siv. Kev nkag siab txog cov qauv no yog qhov tseem ceeb rau kev ua kom zoo ntawm cov khoom siv hauv kev siv tshwj xeeb thiab tsav kev tsim kho tshiab hauv cov ntaub ntawv tshawb fawb.
