Introduction
Silicon nitride-bonded silicon carbide (Si₃N₄-SiC) bricks are advanced refractory materials primarily composed of silicon carbide sand with silicon nitride as the binding phase. Since both SiC and Si₃N₄ are covalent compounds, sintering is challenging, so industrial production typically employs reaction sintering. Using SiC as the aggregate, metallic silicon powder is added, and an appropriate particle gradation, mixing system, and molding process are selected. After drying, the green bodies are sintered in specialized equipment under a nitrogen atmosphere. During firing, the Si₃N₄ matrix (binding phase) forms gray-white crystals that effectively bond the SiC particles (aggregate) into a spatial network structure, endowing the bricks with unique properties unmatched by other refractories.
Advantage
High Hardness and Wear Resistance
The inherent extreme hardness of silicon carbide, combined with the toughness and strength of the silicon nitride bonding phase, imparts exceptional wear resistance to these bricks. Under severe operating conditions-including high temperatures, pressures, and frictional forces-their surfaces remain smooth and intact over prolonged periods, minimizing material loss and equipment failures caused by abrasion.
In metallurgical applications such as blast furnaces and hot blast furnaces, this property enables effective resistance to impact and friction from charging materials, significantly extending equipment service life.
High Thermal Conductivity
Both silicon carbide and silicon nitride exhibit high thermal conductivity, enabling silicon nitride-bonded silicon carbide bricks to transfer heat rapidly. This property effectively mitigates thermal stress in high-temperature equipment and enhances thermal stability. In applications like ceramic kilns and glass melting furnaces-where rapid heat transfer and uniform heating are critical-the bricks facilitate efficient heat exchange, improve energy utilization, and ensure consistent in-furnace temperatures, thereby enhancing product quality.
Good Thermal Shock Resistance
Silicon nitride-bonded silicon carbide bricks exhibit a low thermal expansion coefficient, and the silicon nitride phase buffers thermal stress at high temperatures, imparting excellent thermal shock resistance. Even under frequent temperature fluctuations and thermal shocks, they maintain structural integrity, resisting cracking and spalling. In thermal equipment such as cement rotary kilns and waste incinerators, these bricks withstand extreme temperature variations, ensuring continuous operation and reducing maintenance frequency.
High Chemical Stability
These bricks exhibit strong resistance to acids, alkalis, and other chemicals, maintaining stable performance in various chemically corrosive environments. In chemical and power industry equipment such as chimneys and desulfurization towers, they effectively withstand erosion from acidic gases and alkaline solutions, enhancing equipment corrosion resistance and service life. Additionally, they resist chemical reactions with metals, slags, and other substances at high temperatures, ensuring consistent chemical stability.
High Strength
Silicon nitride-bonded silicon carbide bricks exhibit high compressive strength at both room and elevated temperatures. At room temperature, their strength exceeds 100 MPa, and they maintain high strength in high-temperature environments. This enables them to withstand significant pressure and loads. In metallurgical and building materials industries, when used for high-temperature load-bearing components such as blast furnace bottoms and hearths, they stably support the weight of upper charging materials, ensuring safe equipment operation.
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We provide one-stop services from technical consultation to design, production, and after-sales support.
Raw Materials
Silicon Carbide (SiC),Silicon powder (Si)
Physical and Chemical Specifications
|
Apparently Porosity |
% |
<17 |
|
Bulk Density |
g/cm3 |
>2.6 |
|
Cold Crushing Strength |
Mpa |
>150 |
|
Modules of Rupture |
(1400℃)Mpa |
43 |
|
SIC |
% |
72 |
|
Si3N4 |
% |
21 |
|
Fe2O3 |
% |
1.5 |
process
Raw Material Processing
Silicon Carbide: Screening and classification to achieve specified particle size distributions.
Silicon Powder: Removal of impurities and refinement through milling or chemical processes.
Additives & Binding Agents: Preparation of binders (e.g., clay, resins) and additives (e.g., antioxidants).
Mixing
Dosing & Homogenization: Precise blending of raw materials to ensure uniform composition.
Molding
Method Selection: Depending on brick geometry (e.g., pressing, isostatic pressing, extrusion).
Mold Preparation: Cleaning and lubrication of molds to facilitate demolding.
Forming Operation: Compaction of the mixture into desired shapes under controlled pressure.
Drying
Moisture Removal: Sequential drying via natural air drying followed by thermal drying to ≤0.5% moisture content.
Firing
Kiln Loading: Arrangement of green bodies with proper spacing to ensure uniform heat distribution.
Nitriding Sintering: Reaction bonding in a nitrogen atmosphere at 1400–1500°C to form the Si₃N₄ binding phase.
Controlled Cooling: Gradual cooling to prevent thermal stress cracking.
Applications
Silicon nitride-bonded silicon carbide bricks have a wide range of applications across various industries. The following are some examples:
Fertilizer Nitrogen Furnaces, Oil Vaporizers, Desulfurization Furnaces
Linings in these units utilize Si₃N₄-SiC products to withstand chemical corrosion from various process media. Their high resistance to chemical attack ensures equipment reliability and extends operational life.
Ceramic Kilns
Silicon nitride-bonded silicon carbide (Si₃N₄-SiC) products are used in ceramic kiln components, including flame separators, kiln furniture (scaffolding, columns, rollers, brackets, beams, setter plates, saggers), fish-shaped plates, and high-temperature burners. Leveraging their high-temperature strength, thermal shock resistance, oxidation resistance, and thermal conductivity, these materials enable:
Weight Reduction: Lighter kiln furniture reduces energy consumption.
Improved Efficiency: Faster heat transfer and uniform heating enhance product quality and yield.
Extended Lifespan: Resistance to thermal cycling and oxidation prolongs kiln component service life.
Glass Annealing Furnaces & Enamel Firing Furnaces
Linings in these furnaces utilize silicon nitride-bonded silicon carbide (Si₃N₄-SiC) materials due to their exceptional high-temperature stability, oxidation resistance, and thermal shock resistance. These properties enable the linings to endure extreme temperatures and thermal cycling within the furnaces, ensuring continuous operation and extending service life.
Zinc Furnaces
In vertical zinc retorts, the outer walls are exposed to 1300–1340°C flames, while the inner surfaces contact zinc vapor and slag up to 1200°C.
High Thermal Conductivity: Reduces temperature gradients in the high-temperature zone by approximately 30°C, improving energy efficiency.
Erosion Resistance: After 20 months of service, residual thickness in the hottest zones exceeds that of clay-bonded SiC bricks by 40–50 mm.
Other Non-Ferrous Metallurgy Applications
Aluminum Refining Furnaces: Linings
Zinc Distillation Retorts: Linings and trays
Molten Metal Handling: Degassing rotors, pipelines, suction pumps, filters, crucibles
Process Components: Thermocouple protection tubes for Al-Zn melt temperature measurement, ceramic launders for aluminum casting
These applications leverage key properties such as resistance to molten metal erosion, high strength at elevated temperatures, oxidation and thermal shock resistance, chemical corrosion resistance against cryolite and other electrolytes, and high thermal conductivity for efficient heat transfer.
Buy ZINFON Silicon Nitride Bonded Silicon Carbide Brick at reasonable price
It is understood that the price of Silicon Nitride Bonded Silicon Carbide Brick is a key factor that influences customers to buy. Therefore, we offer affordable Silicon Nitride Bonded Silicon Carbide Brick for sale. There are several reasons why ZINFON offers affordable Silicon Nitride Bonded Silicon Carbide Brick.
factory price
By cooperating with zinfon, we ensure that our customers enjoy ex-factory prices for silicon nitride combined with silicon carbide bricks. This allows customers to reduce the costs of middlemen or distributors. Allowing customers to get the most cost-effective pricing directly from the source. If you want to buy the cheapest refractory bricks, contact us today.
Low raw material costs
One of the key factors for the low price of silicon nitride combined with silicon carbide bricks is the low cost of the raw material, which is abundantly available around ZINFON. As a result, ZINFON has low production costs and high quality. With its high quality materials, customers can obtain affordable products with excellent performance.
mass production
ZINFON possesses advanced production equipment and technologies that enable the plant to realize economies of scale and reduce unit production costs. In addition, the large-scale production of silicon nitride combined with silicon carbide bricks not only helps ZINFON to optimize its resources, but also ensures a continuous supply of high-quality products at favorable prices.
It is important to note that price is an important factor, but it should not be the sole determining factor in your purchasing decision. Quality, reliability and technical support are equally important considerations for ZINFON when purchasing silicon nitride bonded silicon carbide bricks.
By choosing ZINFON as your supplier, you can find high-quality silicon nitride bonded silicon carbide bricks and a wide range of other refractory materials as well as comprehensive support. Contact ZINFON Refractories today to discuss your specific requirements and receive a customized solution!
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