Properties of Silicon Carbide Crystal
Physical Properties
Silicon carbide is recognized for its hardness, second only to diamond and boron carbide. It also has a high thermal conductivity, making it an excellent heat dissipater.
Chemical Properties
One of the unique aspects of silicon carbide is its resistance to oxidation and corrosion, thanks to the silicon oxide layer that forms on its surface when exposed to air.
Resistance to Heat
Silicon carbide can withstand extremely high temperatures, making it an ideal material for environments with intense heat.
Hardness and Durability
Its hardness and durability are impressive, rivaling that of some of the hardest materials known to us.
Structure of Silicon Carbide Crystal
The Basic Structure
The structure of a silicon carbide crystal involves a tetrahedral arrangement of carbon and silicon atoms with strong covalent bonding, which gives it its incredible strength.
Types of Silicon Carbide Crystals
There are many types of silicon carbide crystals, each with different physical properties. Some of the most common types include (β) 3C-SiC, 4H-SiC, and (α) 6H-SiC.
Production of Silicon Carbide Crystal
The Acheson Process
Silicon carbide’s mass production began in 1891, thanks to Edward Goodrich Acheson. Acheson was trying to make artificial diamonds when he heated a mixture of clay (aluminium silicate) and powdered coke (carbon) in an iron bowl. He observed the formation of blue crystals, which he called carborundum, thinking it was a new compound of carbon and aluminium, akin to corundum. Acheson patented this method, known today as the Acheson process, for making silicon carbide powder on February 28, 1893. His method is still widely used today, and he even formed the Carborundum Company to manufacture bulk SiC, initially for use as an abrasive.
The Lely Method
The Lely method allows the growth of large single crystals of silicon carbide. These can be cut into gems known as synthetic moissanite, a testament to the beauty and versatility of this material.
Applications of Silicon Carbide Crystal
Use in Electronics
Silicon carbide has found its way into the electronics industry due to its excellent semiconductor properties. It’s used in devices that operate at high temperatures or high voltages, or both. The first electronic applications of silicon carbide, such as light-emitting diodes (LEDs) and detectors in early radios, were demonstrated around 1907.
Role in Jewelry and Gemology
The hardness and heat resistance of silicon carbide, coupled with its ability to be cut into gems, make it a valuable material in the field of jewelry and gemology. Synthetic moissanite gems are crafted from silicon carbide crystals and are renowned for their brilliance and fire.
Industrial Applications
Silicon carbide’s robustness, resistance to heat and corrosion, and hardness make it a suitable material for various industrial applications. It’s used in car brakes, car clutches, and even in the ceramic plates of bulletproof vests. Its use extends to any application requiring high endurance.
Conclusion
Silicon carbide crystals, with their unique properties and versatility, have made a significant impact in various fields. Whether in high-tech electronics, the glamour of gemology, or the demanding environments of industrial applications, silicon carbide continues to prove its worth. As our understanding of this material deepens, we can only expect to see its use become more widespread and innovative.
