1. Crystallography thiab Material Basics ntawm Silicon Carbide
1.1 Polymorphism thiab Atomic Bonding hauv SiC
(Silicon Carbide Ceramic Phaj)
Silicon carbide (SiC) yog covalent ceramic khoom tsim los ntawm silicon thiab carbon atoms hauv a 1:1 stoichiometric ratio, txheeb xyuas los ntawm nws qhov tshwj xeeb polymorphism– dhau 250 paub polytypes– tag nrho kev sib koom cov kev taw qhia cov kev sib cog lus sib cog lus tab sis sib txawv hauv pawg ntawm Si-C bilayers.
Ib qho ntawm feem ntau tsim nyog polytypes yog 3C-SiC (cubic zinc blende moj khaum), thiab hexagonal hom 4H-SiC thiab 6H-SiC, txhua qhov kev nthuav qhia hloov maj mam hloov pauv hauv bandgap, electron mobility, thiab thermal conductivity uas cuam tshuam rau lawv qhov tsim nyog rau kev siv cov ntsiab lus.
Lub toughness ntawm Si– C daim ntawv cog lus, nrog ib daim ntawv cog lus zog ntawm roughly 318 kJ/mol, underpins SiC qhov zoo kawg nkaus solidity (Mohs solidity ntawm 9– 9.5), siab melting factor (~ 2700 ° C), thiab tiv thaiv kev puas tsuaj rau tshuaj lom neeg thiab thermal shock.
Hauv cov ntawv ceramic, cov polytype feem ntau xaiv raws li qhov xav tau siv: 6H-SiC yeej nyob rau hauv cov ntawv thov kev tsim vaj tsev vim nws qhov yooj yim ntawm kev sib txuas, thaum 4H-SiC tswj nyob rau hauv high-power electronics rau nws superior nqi muab lub rooj zaum log.
Qhov dav bandgap (2.9– 3.3 eV nyob ntawm polytype) Tsis tas li ntawd ua rau SiC qhov tshwj xeeb hluav taws xob insulator hauv nws hom ntshiab, Txawm hais tias nws tuaj yeem doped los ua haujlwm ua ib qho semiconductor hauv cov cuab yeej tshwj xeeb digital.
1.2 Microstructure thiab Theem Purity hauv Ceramic Phaj
Kev ua tau zoo ntawm silicon carbide ceramic daim hlau yog qhov tseem ceeb nyob ntawm microstructural nta xws li grain loj, tuab, theem homogeneity, thiab muaj cov theem ntxiv lossis cov kab mob sib kis.
High-qib phaj feem ntau yog tsim los ntawm submicron los yog nanoscale SiC hmoov nrog sophisticated sintering txoj kev, ua rau nplua-grained, tag nrho ntom microstructures uas ua rau txhua yam toughness thiab thermal conductivity.
Cov pa paug xws li cov pa roj carbon monoxide pub dawb, silica (SIJ OB), los yog sintering pab zoo li boron los yog lub teeb yuag aluminium yuav tsum tau tswj kom huv si, raws li lawv tuaj yeem tsim cov yeeb yaj kiab intergranular uas txo qis qhov kub thiab txias thiab oxidation tsis kam.
Rov ua dua porosity, kuj nyob ntawm qhov txo qis (
Advanced Ceramics nrhiav tau rau lub Kaum Hlis 17, 2012, yog lub tuam txhab high-tech cog lus rau kev tshawb fawb thiab kev tsim kho, ntau lawm, ua, kev muag khoom thiab kev pabcuam ntawm cov ntaub ntawv txheeb ze ceramic xws li Silicon Carbide Ceramic Phaj. Peb cov khoom suav nrog tab sis tsis txwv rau Boron Carbide Ceramic Cov Khoom, Boron Nitride Ceramic Khoom, Silicon Carbide Ceramic Khoom, Silicon Nitride Ceramic Khoom, Zirconium Dioxide Ceramic Khoom, lwm. Yog koj txaus siab, thov koj xav tiv tauj peb.
Cim npe: silicon carbide phaj,carbide phaj,silicon carbide ntawv
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