Reaction Bonded Silicon Carbide

Silicon Carbide is one of the hardest and most durable ceramic materials on the market, providing protection from corrosion, wear, and high temperatures.

Reaction-bonded silicon carbide is produced by reacting porous carbon with liquid or gaseous silicon and infiltrating it with additional silicon to create a dense ceramic part.

Nitride Bonded Silicon Carbide (NB SiC)

Nitride Bonded Silicon Carbide (NB SiC) is a composite refractory material composed of silicon carbide nitride as its ceramic phase to form a strong, resilient and durable material. As one of the hardest engineering materials available today, NB SiC resists wear from particles or hard surfaces like surfaces. Furthermore, its chemical inertness allows it to remain resistant to most acids, alkalis, and halides while being highly ductile and capable of withstanding heavy loads and impact.

Nitride-bonded silicon carbide can be easily formed into intricate and precise shapes through the Blasch process, enabling it to be used in applications requiring both refractory and mechanical properties. Furthermore, its fracture toughness exceeds that of sintered SiC, making it suitable for demanding environments involving abrasion and impact stress.

Note that there are two methods for manufacturing silicon carbide: reaction bonding and sintering. Each forming method greatly impacts the microstructure of the end product, leading to different thermal and mechanical properties than when manufactured solely through sintering. Below is an outline of each of these forming techniques:

Reaction bonded silicon carbide is formed by adding liquid silicon into a compact that contains mixtures of SiC and carbon, reacting with carbon to form additional silicon carbide grains while binding together initial grains of SiC. Once formed, this material can be easily formed into various shapes and sizes making it suitable for applications such as kiln furniture, mechanical seals and flow control chokes.

Nitride-bonded silicon carbide has long been utilized for applications involving abrasion resistance; however, in erosion resistance tests in soil conditions it has also proven itself an outstanding performer against sintered boron-containing steel products in both loose and dense soil conditions.

InVinCerTM by Blasch

Reaction bonding is an innovative technique used to produce silicon carbide ceramic parts of any shape or size, using less expensive production processes than sintered silicon carbide (SSC). Refractory ceramics made using this technology are known for their strength, corrosion resistance and extreme temperatures resistance – these qualities make them suitable for heating devices like kiln furniture as well as wear components such as seals and valves.

Refractory ceramics produced using this technology are known for their superior thermal shock resistance. Flexural and fracture toughness increase with an increase in solid content of reaction-bonded silicon carbide; this material forms due to a chemical reaction between porous carbon or graphite and molten silicon; its main fracture mode involves intergranular fracture of SiC as well as brittle fracture from residual carbon particles.

To achieve reaction bonded silicon carbide, first combine coarse silicon carbide powder and non-oxide sintering aids before heating until reaching 2000F. Following that step, precision grinding techniques may be utilized to complete the mixture.

As part of the gelcasting of reaction-bonded silicon carbide, the ratio between furfuryl alcohol (FA) and phenolic resin was adjusted to facilitate polymerization and gel time modification. Furthermore, both gel time and pore morphology of microporous carbon were studied; both proved instrumental in creating reactively-bonded silicon carbide structures.

Refractory ceramics produced using this technology are known as RBSC. Figure 9 displays XRD patterns of SiC/porous carbon bodies with different solid loadings produced using this process; their results show that those with higher solid content contained less free Si, evidenced by increased peak intensities for both a-SiC phase and b-SiC phase in these refractory ceramics.

Calsic® RB

Reaction bonded silicon carbide (RBSC) is an innovative ceramic material, featuring exceptional strength and hardness while being capable of withstanding extreme temperatures. Due to these properties, RBC makes for an excellent material choice in kiln furniture, mechanical seals, and semiconductor manufacturing equipment applications.

RB SiC is typically created by mixing SiC powder with carbon and plasticizer in a mold, firing to remove plasticizer and infusing with liquid or vapour silicon that reacts with carbon to form additional silicon carbide – this results in an extremely dense high performance product with excellent wear and impact resistance.

Composition, morphology and size of carbon sources play an enormous role in shaping the microstructure and properties of RB SiC ceramics. Generally speaking, more carbon content in the preform results in greater concentration of RB SiC in the final ceramic. Furthermore, their reactiveness also has an impactful presence in this process: from highly reactive graphite to less reactive micro-spherical carbon.

Which type of SiC is appropriate for your application will depend on its intended use, such as hardness, density and corrosion resistance requirements. Both nitride bonded and reaction bonded silicon carbide offer exceptional performance in harsh environments.

Sintered silicon carbide (SSiC), produced through pressing and sintering, outshines RB SiC in terms of strength and hardness; however, its thermal conductivity is lower due to more complex sintering processes requiring much higher temperatures for production; additionally it’s more costly due to complex production methods required by this material – thus rendering some applications unsuitable for this form. Luckily Saint-Gobain Performance Ceramics & Refractories can assist you in selecting the appropriate ceramic for your application with our full line of industrial-grade wear resistant products tailored specifically designed to meet specific requirements – call today for more information or help deciding on your application!

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