Analysis of impurities in silicon carbide crystal

Impurities in the silicon carbide crystal are: iron, aluminum, calcium, magnesium, and silicon oxides and carbides, and their eutectic.
These impurities in the smelting furnace thermal power conditions, the temperature in the 2100 - 2200 ℃ is evaporated when discharged, move into the cooler areas of the furnace, only a small part of the carbide SiC crystals incorporated into the crystalline state lattice, forming a sheet-like fine crystal. The entire silicon carbide crystal brittle, poor toughness, low strength (which is in the processing of silicon carbide products, crushing, by sieve classification, the fine particles of silicon carbide SiC content of less than the content of coarse phenomenon proof).
The decomposition temperature of silicon carbide is greater than 2400 ℃, in the decomposition, while the silicon carbide containing various impurities in the crystal lattice due to a temperature rise at the same time, thermal power can be discharged, moved to the lower temperature zone. The silicon carbide crystal product purification. Longer refining time, impurities in the silicon carbide crystal with many crystals → decomposition → recrystallization, purification repeated several times, and then purification, crystal growth of silicon carbide, and then grow to grow large enough to form a dense of the crystal, the crystal reduces porosity.
Decomposition of silicon smelting, is essentially the product purification process. The more times the decomposition process, the product sufficient degree of purification, the more thorough the degree of purification, the more pure final product, the product less impurity content, the higher the toughness and strength, the more stable chemical properties.