Crystal structure of silicon carbide
SiC is a covalently-based covalent compound. Since carbon and silicon form SiC crystals, the migration of S→P electrons in SiC atoms leads to energy-stable SP3 hybrid arrangement, thus forming SiC with diamond structure. . Therefore its basic unit is a tetrahedron. All SiC are stacked from SiC tetrahedrons, except for parallel or anti-parallel bonding.
There are 75 variants of SiC, such as α-SiC, β-SiC, 3C-SiC, 4H-SiC, 15R-SiC, etc. All of these structures can be divided into cubic, hexagonal and rhombohedral systems. Among them, α-SiC and β-SiC are the most common. α-SiC is a high temperature stable type, and β-SiC is a low temperature stable type. β-SiC can be converted to α-SiC at 2100~2400 °C. β-SiC can be prepared from a simple mixture of silicon and carbon at a temperature of around 1450 °C. Polymorph analysis and quantification of SiC microcrystals can be performed using transmission electron microscopy and X-ray diffraction techniques.
The application of SiC ceramics in many industrial fields shows excellent performance, which has attracted widespread attention. SiC ceramics are a large family in the field of inorganic non-metallic materials, and their antennae extend almost all industrial fields. However, due to the poor sinterability of SiC ceramics, its fabrication process and production are relatively expensive. Reducing the firing temperature of SiC ceramics and finding new and inexpensive production processes are still the focus of materials workers. At the same time, mining and developing all the advantages of SiC ceramics (powder) for the benefit of mankind is also the focus of our work. SiC ceramics have its broad development and application prospects
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