1. Crystallography and Material Principles of Silicon Carbide
1.1 Polymorphism and Atomic Bonding in SiC
(Silicon Carbide Ceramic Plates)
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– over 250 well-known 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 bond, nrog daim ntawv cog lus lub zog ntawm ib puag ncig 318 kJ / mol, txhawb nqa SiC qhov nyuaj zoo kawg nkaus (Mohs hardness ntawm 9– 9.5), siab melting point (~ 2700 °C), thiab tsis kam rau tshuaj lom neeg corrosion thiab thermal shock.
Hauv cov phaj ceramic, lub polytype feem ntau yog xaiv raws li lub hom phiaj siv: 6H-SiC yog favored nyob rau hauv architectural daim ntawv thov vim nws yooj yim ntawm synthesis, thaum 4H-SiC yog nyiam nyob rau hauv high-power electronics rau nws exceptional charge carrier mobility.
Qhov dav bandgap (2.9– 3.3 eV nyob ntawm polytype) kuj ua rau SiC yog qhov zoo tshaj plaws hluav taws xob insulator hauv nws daim ntawv ntshiab, txawm hais tias nws tuaj yeem doped los ua semiconductor hauv cov khoom siv hluav taws xob tshwj xeeb.
1.2 f
Kev ua haujlwm ntawm silicon carbide ceramic phaj yog heev nyob ntawm cov yam ntxwv microstructural xws li cov nplej loj, e, m, thiab lub xub ntiag ntawm theem ob lossis impurities.
Cov phaj qib siab feem ntau yog ua los ntawm submicron lossis nanoscale SiC hmoov siv cov txheej txheem sintering siab heev, t, tag nrho cov microstructures ntom ntom uas ua rau cov neeg kho tshuab lub zog thiab thermal conductivity.
Impurities xws li cov pa roj carbon ntxiv, silica (SiO₂), lossis sintering pab xws li boron lossis txhuas yuav tsum tau ua tib zoo tswj hwm, vim tias lawv tuaj yeem tsim cov yeeb yaj kiab intergranular uas txo qis lub zog kub thiab oxidation tsis kam.
Residual porosity, txawm tias nyob rau theem qis (
a 17, 2012, b, ntau lawm, C, kev muag khoom thiab kev pabcuam thev naus laus zis ntawm cov khoom siv ceramic-ntsig txog xws li Silicon Carbide Ceramic Plates. Peb cov khoom suav nrog tab sis tsis txwv rau Boron Carbide Ceramic Products, Boron Nitride Ceramic Products, Silicon Carbide Ceramic Products, Silicon Nitride Ceramic Products, Zirconium Dioxide Ceramic Products, v. Yog tias koj txaus siab, thov koj xav tiv tauj peb.
Tags: Silicon Carbide Phaj,Carbide Phaj,Silicon Carbide Sheet
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