In 1891, it was a eureka moment for Edward Goodrich Acheson when he accidentally discovered Silicon Carbide. This amazing compound was produced in form of bright green crystals, hard enough to cut glass and even diamond. It was the first man-made abrasive and was initially used to polish gems. It has been used in so many fields like automobile parts, fuel for production of steel, high voltage parts and so on. One such use is in the production of Ceramics. This article aims to shed some light on these kinds of Ceramics. We will discuss its uses, benefits, and applications. Let’s begin.
What is “Silicon Carbide Ceramics”?
Silicon Carbide Ceramics are black in color and have high strength. These are believed to be the hardest. These have thermal shock resistance better than alumina. These hard ceramics consist of grains of SiC bound together with the help of Sintering.
What are its uses?
Ceramics that are based on Silicon Carbide are used for manufacturing of articles that are going to be subjected to intense mechanical wear and extremely high temperatures. These can maintain mechanical strength at the high temperature of 1400 C. These are widely used in many industries like nuclear power, machine building, and metal.
How are these Ceramics produced?
They are produced by two methods:
- Reaction Bonded
- Sintered – The main method to form ceramics that are based on Silicon Carbide is high-temperature sintering of SiC powder with various binding additives. Given below are the most widely used types of ceramics and the mode of their preparation.
- Silicon Nitride Bonded- It is produced from a mixture of Silicon Carbide granules and Silicon, in a nitrogen atmosphere at a temperature below the melting point of Silicon.
- Reaction Bonded- It is made from granules Silicon Carbide and fine powder of silicon and graphite. Heat treatment carried out in 1500- 1650 C.
- Direct Sintered- A pulp-like material is prepared from – SiC powder, synthesizing additives of boron and aluminum, various binding agents and carbon-containing additives. The pulp is used to make the required pieces by drying at the temperature of 2050 C.
- Composite Bonded- Fine powder of pure SiC is mixed with Silicon and binding material. Heated in a nitrogen environment at a temperature above 1350 C.
Benefits of Silicon Carbide based Ceramics:
- These have High Thermal Conductivity
- Have Low Thermal Expansion.
- Have Excellent thermal shock resistance.
- Are known for their Hardness.
- Possess properties of a Semiconductor.
- RI (Refractive Index) is greater than that of a diamond.
Application of Silicon-Based Ceramics:
- Wear-resistant nozzles and other wear parts.
- Thermocouple protection tubes.
- Kiln system components.
- Faucet washers.
- Ceramic armor protection systems.
- Heating elements.
- Bearings for high temperatures.
- Used in thin filament pyrometry and steel production.
Sic has the highest corrosion resistance out of all the ceramic materials. Their superior properties for power devices have revolutionized the power electronics industry. Though it was accidentally discovered, it sure has made a concrete place for itself. Isn’t it? Let us know your views.