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, 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 prevails in architectural applications due to its ease of synthesis, while 4H-SiC dominates in high-power electronics for its exceptional fee carrier flexibility.
The large bandgap (2.9– 3.3 eV depending upon polytype) also makes SiC an excellent electrical insulator in its pure form, though it can be doped to function as a semiconductor in specialized electronic tools.
1.2 f
The efficiency of silicon carbide ceramic plates is critically dependent on microstructural attributes such as grain dimension, e, m, and the visibility of secondary stages or 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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