1. Crystallography thiab Material Principles ntawm Silicon Carbide
1.1 Polymorphism thiab Atomic Bonding hauv SiC
(Silicon Carbide Ceramic Phaj)
Silicon carbide (SiC) is a covalent ceramic compound made up of silicon and carbon atoms in a 1:1 stoichiometric proportion, distinguished by its amazing polymorphism– dhau 250 paub zoo polytypes– all sharing strong directional covalent bonds but varying in stacking series of Si-C bilayers.
One of the most technologically relevant polytypes are 3C-SiC (cubic zinc blende structure), and the hexagonal kinds 4H-SiC and 6H-SiC, each showing refined variations in bandgap, electron flexibility, and thermal conductivity that influence their viability for particular applications.
The toughness of the Si– C daim ntawv cog lus, with a bond power of around 318 kJ/mol, underpins SiC’s phenomenal firmness (Mohs solidity of 9– 9.5), high melting factor (~ 2700 ° C), and resistance to chemical degradation and thermal shock.
In ceramic plates, the polytype is generally selected based upon the meant use: 6H-SiC yeej nyob rau hauv kev siv vaj tse vim nws yooj yim ntawm kev sib txuas, thaum 4H-SiC dominates nyob rau hauv high-power electronics rau nws exceptional nqi cab kuj yooj yooj yim.
Qhov loj bandgap (2.9– 3.3 eV nyob ntawm polytype) kuj ua rau SiC ib qho zoo heev hluav taws xob insulator hauv nws daim ntawv ntshiab, Txawm hais tias nws tuaj yeem raug doped los ua haujlwm ua ib qho semiconductor hauv cov cuab yeej hluav taws xob tshwj xeeb.
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 yam ntxwv xws li grain dimension, tuab, theem homogeneity, thiab qhov pom ntawm theem nrab lossis impurities.
Cov phaj qib siab feem ntau yog tsim los ntawm submicron lossis nanoscale SiC hmoov ntawm cov txheej txheem sintering siab heev, ua rau nplua-grained, tag nrho ntom microstructures uas optimize mechanical zog thiab thermal conductivity.
Cov pa phem xws li cov pa roj carbon monoxide pub dawb, silica (SiO ₂), los yog sintering pab zoo li boron los yog txhuas yuav tsum tau ua tib zoo tswj, raws li lawv tuaj yeem tsim cov yeeb yaj kiab intergranular uas txo qhov kub thiab txias zog thiab oxidation tsis kam.
Residual porosity, txawm nyob rau theem 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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