Silicon carbide is a naturally occurring, strong, sharp material known for its hardness properties. It crystallizes into a closely packed covalent bond structure, forming a tetrahedral coordination among 4 silicon and 4 carbon atoms. The output material gains high strength due to tetrahedral units’ tight stacking layout.
Chemical Properties of Silicon Carbide (SiC)
The chemical properties of silicon carbide include:
- Maximum resistance to common inorganic and organic acids, salts, and alkali environments. The material can withstand prolonged exposures to these, except for acid fluorides and hydrofluoric acids.
- Distinct electrical properties make it a suitable candidate for semiconductor applications. It exhibits electrical resistance due to varying compositions by up to 7 orders of magnitude.
Physical Properties of Silicon Carbide
Silicon carbide exhibits the following physical properties:
- It has no odor of its own
- It can have grey, black, or green-colored powder forms
- The specific density is 3.21 grams per cubic centimeters
- It is not soluble in alcohol, acids, and water.
The most widespread use of silicon carbide is in the form of abrasives, thanks to the low cost and durability of the material. As an abrasive, it is used in several industrial processes, including grinding, honing, sandblasting, and water-jet cutting.
Different types of silicon carbide abrasives: Characteristics and Uses
- Sintered Silicon Carbide– Sintered SiC (Silicon Carbide) is obtained as a self-bonded material when sintered in the presence of a sintering agent, e.g., Boron. Sintering is a heating process that can be achieved through recrystallization, hot pressing, microwave sintering, pressure-less sintering, and reaction sintering.
Sintered silicon carbide exhibits the following characteristics:
- Exceptional resistance to corrosion owing to the absence of binder.
- High strength that provides for superior abrasion resistance and wears.
- Creep resistance along with resistance to high temperatures up to the range of 1750°C
- Good resistance to thermal shock up to 125W/mK
Uses for sintered silicon carbide
- Chemical industry
- Pulp and Paper industry
- Power Generation
- Petrochemical industry
- Mining operations
- Nitride bonded silicon carbide
Silicon carbide molecules bonded together by the use of silicon nitride. The material is relatively low on corrosion and wears resistance compared to the sintered silicon carbide. But it scores in terms of economic application, where high performance is not a prerequisite. And is common in the case of metal alloy components.
Characteristics that make nitride bonded silicon carbide ideal for use are:
- Thermal shock resistance can be achieved with a relatively low economical cost of operation
- The material has resistance to erosion and spalling and can last longer in comparison to rubber and steel
- Like other silicon carbide-based abrasives, nitride-bonded silicon carbide too has excellent corrosion resistance
- It does not tend to crack or disintegrate under high temperatures
Uses for nitride bonded silicon carbide
- Mining industry
- Petrochemical industry
- Aluminum Processing operations
- Chemical processes
- Power Generation
- Red Metal processing – brass, bronze, and copper
- Reaction bonded silicon carbide
Also known as siliconized silicon carbide, the silicon metal is ‘infiltrated’ to turn into a ceramic with thermal, mechanical, and electrical properties. The material works wonders when used as a liner for pipes, control flow chokes, and mining operations.
Characteristics of reaction bonded silicon carbide include:
- Hardness in the range of 2500-2550 Knoop
- High tensile strength as well as flexural strength
- Good thermal conductivity accompanied by low thermal expansion
- High resistance to corrosive fluids like acids and alkalis
Uses for reaction bonded silicon carbide
- Liners in pipes
- Low mass kiln supports
- Flow control chokes
- Burner nozzles and setters
- Mining industry
- High-precision components like laser mirror blanks and optical benches
- Clay-bonded silicon carbide
Clay-bonded silicon carbide is obtained from a pressure-less sintering process involving silicon carbide dusting powder (raw material) and clay as a sintering additive. Silicon carbide is powdered in the ball mill to achieve consistent particle size as it also helps improve the overall density. The end product is an oxide-bonded silicon carbide abrasive material.
Characteristics of clay bonded silicon carbide include:
- High thermal conductivity
- The coefficient of thermal expansion manages to stay small in value
- The resistance to thermal shocks is great
- Resistance to wear isamazing
Uses for clay bonded silicon carbide
- Clay bonded silicon carbide is popularly used in the manufacture of ceramic kiln furniture
- Muffle furnace covers are prepared from the material for long-term use
- Furnaces across industries where furnace linings are subjected to high temperatures for extended periods
- Use as material for distillation tank in processes involving zinc distillation furnaces
- Cement industry
- Silicon nitride bonded silicon carbide
Simply put, it is silicon carbide bonded by silicon nitride molecules. It is known for its hardness, which is second only to diamond.
Characteristics of silicon nitride bonded silicon carbide
- Superior hardness to the Mohs hardness of more than 9.
- High resistance to high temperature. The material retains the same strength and hardness at 1400C as it does at room temperature
- Low coefficient of thermal expansion with higher thermal conductivity
- Creep resistance at higher temperatures
- Lost cost of production
Uses for silicon nitride bonded silicon carbide
- Iron and steel industry
- Chemical industry
- Building and construction materials
- Energy savings, wherever feasible
- Chemical vapor deposited silicon carbide
Using a linear growth process, CVD silicon carbide combines chemical vapors with silicon carbide molecules. The output material is so densely packed that its porosity is 0%.
Characteristics of chemical vapor deposited silicon carbide
- High density for the value 3.18 grams per cubic centimeters
- Thanks to high density, the porosity is reduced to zero percent
- The material has an electrical resistivity of about 1500 μΩm
It is a semi-friable, medium-density abrasive. The production may involve resin or vitrified points and wheels. It is commonly used to grind brittle surfaces.
Black silicon carbide has about 98.5% of silicon carbide. It is tougher than green silicon carbide.
Characteristics of black silicon carbide
- High resistance to wear
- Corrosion resistance, even at high temperatures
- The material exhibits superior refractoriness
- The material stays chemically stable even at high temperatures
Uses of black silicon carbide
- Used to process low tensile strength materials like glass, stone, refractory materials, ceramics, and non-ferrous metals.
- Abrasive applications in the glass industry and manufacture of sandpaper
- Ceramic industry
- Power production (desulfurization systems)
- Refractory applications
It is known as the purest form of naturally occurring silicon carbide. It is obtained from grinding raw blocks on silica carbide as a fine powder. It has a medium density and is a friable abrasive. It contains more than 99% silicon carbide.
Characteristics of green silicon carbide
- The material exhibits strong oxidative resistance
- It remains stable in the presence of chemicals like strong alkalis and acids
- It is harder than black silicon carbide with 9.5 Mohs hardness
- High thermal resistance and strength at high temperatures up to 1900 C.
Uses of green silicon carbide
- Refractory industry
- Exterior painting of non-ferrous metals
- High-temperature seals and furnace parts
- Grinding and polishing operations
Products made from silicon abrasives
1. Silicon Carbide Powder – It is produced through a reaction and pyrolysis of vaporized polysiloxanes under high temperatures. As the process is straightforward, it only requires a reaction chamber heated to about 1600C. It finds use in abrasive machining processes like sandblasting, grinding, and water-jet cutting. The semiconductor industry uses it for fine-grinding semiconductors. It is also helpful in the case of ferrous materials and ceramics polishing processes. Other applications include processes including honing, shaping, and polishing.
2. Silicon Carbide Sandpaper – Silicon carbide sandpaper is most commonly used in the automotive, marble, and stone industries. It helps with cost-effective operations like deburring glass and metal surfaces and refinishing wooden floors. The silicon carbide grits on the sandpaper are sharp and very hard. Plastics and medium-density fiberboards can easily be sanded with them.
3. Silicon Carbide Grinding Wheel – The hard and pointy silicon carbide grits are pasted onto the wheel surface for continuous, controlled grinding or abrasive operations. The base grinding wheel is typically made of composite materials with varying densities depending on the target operation. The continuous spinning wheel supports continuous fast-cutting applications. The target metal surfaces are generally softer metals like aluminum and cast iron.
Black silicon carbide particles are generally used for machining surfaces of plastics and stones. At the same time, the green silicon carbide particles are used to grind carbide materials.
4. Silicon Carbide Sharpening Stone – We commonly come across grading stones at our home used to sharpen the knives and scissors made from hard stainless steel. Hence silicon carbide sharpening stones come out as a tough material that can sharpen hard metals. It has a hardness in the range of 9-10 Mohs. Moreover, it can be used with water or oil as coolants and friction reduction mediums.
5. Silicon carbide sanding belts -Silicon carbide particles adhered to rapidly spinning belts are durable for fine grinding and sanding operations. The base sand cloth can have varying densities to support the silicon carbide abrasive action. They are instrumental in polishing soft metals like zinc, copper, and aluminum alloys.
Silicon carbide is made up of two components, silicon and carbon. The cohesive bonding between the two leads to a hard, durable material that can be used for various abrasion applications. It is indeed a nature’s wonder and very useful in several industrial and domestic operations.
Silicon Carbide Ceramic Powder
Silicon carbide ceramic powder is a man-made material that combines silicon and carbon. It is a very hard and durable material with high thermal conductivity and resistance to corrosion. Silicon carbide ceramic powder is a versatile material with many applications. Its unique properties make it ideal for many demanding applications.
Here are some of the specific properties of silicon carbide ceramic powder:
- Hardness:Silicon carbide ceramic powder is one of the hardest known materials, with a Mohs hardness of 9. It is even harder than diamonds.
- Thermal conductivity:Silicon carbide ceramic powder has excellent thermal conductivity, about 4 times that of aluminum. This makes it ideal for applications where heat needs to be transferred quickly, such as in electronics.
- Corrosion resistance:Silicon carbide ceramic powder is very resistant to corrosion from acids and alkalis. This makes it ideal for applications where it will be exposed to harsh environments.
- High-temperature stability:Silicon carbide ceramic powder can withstand temperatures up to 2,500 degrees Celsius. This makes it ideal for applications where it will be exposed to high temperatures, such as in kilns and furnaces.
Different types of silicon carbide ceramic powder: Characteristics and Uses
1. Sintered silicon carbide (SSC)– This is the most common type of silicon carbide ceramic powder. It is made by sintering, or fusing, silicon carbide powder at high temperatures. SSC is a very hard and durable material with excellent thermal conductivity. It is used in various applications, including abrasives, refractories, electronics, and composites.
- Very hard
- Good thermal conductivity
2.Nitride bonded silicon carbide (NBSC)– This type of silicon carbide ceramic powder is made by bonding silicon carbide powder with silicon nitride. NBSC is a very strong and lightweight material with good thermal conductivity. It is used in a variety of applications, including cutting tools, armor, and bearings.
- Good thermal conductivity
- Cutting tools
3.Reaction bonded silicon carbide (RBSC)– This type of silicon carbide ceramic powder is made by reacting powdered silicon carbide with carbon. RBSC is a very porous material with good thermal insulation properties. It is used in various applications, including kiln shelves, furnace linings, and heat shields.
- Good thermal insulation
- Kiln shelves
- Furnace linings
- Heat shields
4.Ceramic whisker– This type of silicon carbide ceramic powder is made by growing long, thin silicon carbide crystals. Ceramic whiskers are very strong and lightweight materials with good electrical conductivity. They are used in a variety of applications, including composites, sensors, and actuators.
- Good electrical conductivity
Products made from silicon carbide ceramic powder
Here are some of the products made from silicon carbide ceramic powder. This versatile material is used in various industries, and its unique properties make it ideal for many demanding applications.
- Abrasives– Silicon carbide ceramic powder is used in various abrasive products, such as sandpaper, grinding wheels, and cutting tools. It is a very hard material that can withstand high wear rates. For example, silicon carbide sandpaper is used to smooth and polish wood, metal, and other materials.
- Refractories –Silicon carbide ceramic powder is used in high-temperature applications, such as kiln shelves and furnace linings. It is a very stable material that can withstand high temperatures without melting or decomposing. For example, silicon carbide kiln shelves are used in high-temperature kilns to fire ceramics, fusing, or casting.
- Electronics– Silicon carbide ceramic powder is used in various electronic applications, such as power transistors, high-voltage diodes, and high-temperature sensors. It is a good conductor of heat and electricity and also corrosion-resistant. For example, silicon carbide is used in power transistors that can withstand high temperatures and voltages.
- Composite materials– Silicon carbide ceramic powder is used in composite materials, such as carbon fiber-reinforced silicon carbide (CFRC). These materials are very strong and lightweight and are used in various applications, such as aerospace and automotive. For example, CFRC is used in the brakes of high-performance cars because it can withstand the high temperatures and stresses of braking.
- Armor– Silicon carbide ceramic powder is used in armor, such as Chobham armor, and in ceramic plates in bulletproof vests. It is a very hard and durable material that can withstand high-velocity impacts. For example, silicon carbide is used in the armor of tanks and other military vehicles to protect the crew from enemy fire.
Silicon Carbide Refractory
Silicon Carbide Refractory is a material that is used to create a high-temperature resistant and durable refractory material. It is produced from silicon carbide at 2500°C in an electric furnace. It is often used in industrial and commercial applications like glass, ceramics, and metals. It is popularly used as a raw material in the construction of furnaces and other high-temperature applications. Silicon Carbide Refractory is known for its excellent thermal shock resistance and thermal stability. Since the material is highly corrosion-resistant, it is an ideal choice for several industrial applications. We discuss silicon carbide refractory materials, how they are chosen, and their specific industrial applications.
Properties of Silicon Carbide Refractories
Silicon carbide is a very hard and brittle material that is often used in refractories because of its high thermal and mechanical stability. Silicon carbide is made up of a silicon atom in the center of a carbon atom surrounded by six oxygen atoms. The silicon atom has a negative charge, while the carbon atom has a positive charge. This makes silicon carbide a good candidate for refractory use because it can resist heat and mechanical stress. Silicon carbide also has a very high melting point, so it can be used to create very hard refractories.
Silicon carbide is an excellent refractory material because of its high thermal and mechanical stability, melting point, and negative charge. Its unique properties make it an excellent choice for refractories and other high-temperature applications.
Products made from silicon carbide refractory
The use of silicon carbide refractories is growing in industrial applications. These materials are used in various applications, from high-temperature furnaces to nuclear reactors. The following are some typical applications of silicon carbide refractories:
- Nuclear reactors: Silicon carbide refractories are used in nuclear reactors to help protect the reactor walls from radiation.
- High temperature furnaces: Silicon carbide refractories are used in high-temperature furnaces to protect the furnace walls from extreme temperatures.
- Steelmaking: Silicon carbide refractories are used in steelmaking to help protect the furnace walls from the high temperatures associated with steelmaking.
- Ceramics / H.T. Insulators: Silicon carbide refractories are used in the production of ceramics to help protect the kiln walls from the high temperatures associated with ceramics production.
- Glassmaking: Silicon carbide refractories help protect the furnace walls from the high temperatures associated with glassmaking.
- Defense purposes: They help as protective armor for tanks and armored vehicles.
- Industrial coatings: They can form a protective quote as anti-wear lubricants, functional coatings, structural coatings, stealth materials
- Metallurgy: Used as a deoxidizer and exotic material for metallurgical operations
- Other industries: Sanitaryware, kiln furnaces, foundries, muffles, and chamber fronts.
Silicon carbide refractories are used for several industrial applications, such as glass and ceramics. Silicon carbide refractories are also used in producing electric motors, heat exchangers, and other industrial equipment. Silicon carbide refractories are a very efficient and durable material that can withstand heat and pressure.
Applications of Nitride-Bonded Silicon Carbide Refractories
Nitride-bonded Silicon Carbide refractories boast oxidation resistance, high thermal conductivity, and superior thermal shock resistance. Moreover, they possess greater hot strength than oxide-bonded Silicon Carbide refractories, making them an ideal option as kiln furniture. As they do not get wet quickly, they are helpful in non-ferrous metal contact zones. Some applications of nitrite-bonded silicon carbide refractories include:
- Iron & Steel
- Cell lining via aluminum reduction
- Blast furnace lining
- Shaft Furnace lining
We are a reputed silicon carbide manufacturer based in China. As a leading provider of silicon carbide and related products in China, our products find use in refractory, abrasives, technical ceramics, etc. Our production capacity is just one factor that makes us a favored supplier. We have existed for over 20 years, and our supply markets cover America, Canada, Spain, Russia, South Africa, etc. Our annual output is $9.3 million, which translates into 12,800 tonnes of monthly output. Choosing us as your partner in growth means you are assured of our high-quality materials, supported by on-time professional service. We provide black and green silicon carbide for your distinct industrial use.