Reaction Bonded Silicon Carbide

Reaction Bonded Silicon Carbide (RB SiC) is a porous silicon carbide ceramic material with superior thermal and corrosion resistance, produced by infiltrating liquid silicon into an open carbon or graphite preform.

As part of its silicon supply body, phenol resin or furfuryl alcohol resin acts as a bonding agent that ensures proper frame structure when heated, facilitating even melting and eliminating lumping of fused silicon.

Hardness

Reaction-bonded silicon carbide (RB SiC) offers higher hardness than sintered silica but lower than nitride-bonded silicon carbide. Furthermore, its strength and impact resistance surpass that of alumina making it an excellent option for use as pipe and chute lining material.

RB SiC is made by infiltrating liquid silicon into a porous carbon or graphite preform, reacting it with carbon to form SiC and producing lightweight ceramic material with high strength, good chemical resistance, and excellent thermal stability. It can be made in many shapes and sizes for mining equipment applications as wear parts.

Reactivity of carbon in granules can vary depending on its graphitization degree, morphology and size; accordingly, special types of reactivity-enhancing resin and compound carbon sources have been created to enhance reaction-bonding [14].

Furfuryl alcohol resin, epoxy resins, benzyl butyl phthalate di-butyl phthalate methyl ethyl ketone polyvinyl acetate and ethylene glycol can all be used as thermosetting resins in addition to phenol. Plasticizers such as methyl ethyl ketone, methyl acrylate methyl cellulose and glycerol may also be added for better flowability and dimensional accuracy of finished products; their elastic modulus approaches that of sintered silica products.

Corrosion Resistance

Silicon carbide is one of the hardest ceramic materials, maintaining its hardness and strength even at elevated temperatures. Additionally, it resists wear well from both abrasive and erosive wear as well as most acids and alkalis; additionally its thermal conductivity allows it to withstand rapid changes in temperature changes as well.

Corrosion resistance is essential in industrial applications, and reaction bonded silicon carbide offers outstanding corrosion protection across multiple environments. It can withstand dry and moist oxygen environments as well as hot gaseous vapors, mixtures of hot liquid metals and complex environments like coal slags without being affected by corrosion.

Reaction bonded SiC is created by infiltrating porous carbon or graphite preforms with molten silicon, which then reacts with them and forms SiC. While typically having lower strength and hardness than its sintered silicon carbide counterpart, its production costs are considerably less, making this an economical and straightforward material option that’s great for various applications requiring durable ceramic materials that are cost-effective yet straightforward to work with.

Calix Ceramics’ Calsic RB reaction-bonded silicon carbide offers an ideal alternative to sintered material when corrosion or wear resistance aren’t crucial, such as environments requiring durable ceramic that can handle heavy loads and impacts with no cracking issues.

Thermal Stability

Reaction Bonded SiC is an incredibly durable ceramic material, providing excellent resistance against chemical attack, thermal expansion and contraction and high stress/pressure environments, such as burner nozzles, kiln furniture, mechanical seals and larger wear components in mining industries. Furthermore, this material offers exceptional corrosion resistance as well as temperature stability for use under extreme temperatures.

For the production of RB SiC, molten silicon must first be infiltrated into a porous carbon or graphite preform. As it flows infiltrating through, silicon reacts with carbon to form SiC. This results in highly compact bodies with high densities and tight dimensional tolerances; this manufacturing process is known as reaction sintering.

This type of ceramic boasts increased temperature strength and oxidation resistance while having reduced hardness compared to sintered SiC. Furthermore, RB SiC is more permeable to gases and liquids, making it perfect for use in chemical processing machinery.

Due to its production process, RB SC is more cost-effective than sintered SiC. Reaction bonding requires less energy and can be much faster, providing an environmental friendly alternative to traditional ceramics. Furthermore, large size parts that may be difficult to machine using traditional techniques may benefit from its superior mechanical strength and dimensional accuracy provided by its sintering process.

Wear Resistance

Reaction bonded silicon carbide boasts outstanding wear resistance and is extremely resistant to erosion and abrasion, withstanding temperatures without degrading or cracking, boasting a low coefficient of thermal expansion and being acid-corrosion-proof. As such, RB SiC can withstand acid corrosion and often used for parts that will experience frictional forces such as kiln furniture, mechanical seals or larger wear components for mining industries and similar sectors.

Reaction-Bonded Silicon Carbide (RBSC) is manufactured by infiltrating molten silicon into porous carbon that has been packed into its desired shape using heat and pressure from a special reaction bonding furnace, where its heat and pressure cause it to react with carbon particles to form silicon carbide. Manufacturing method depends on desired final product geometry, shape and tolerance requirements.

An anti-wear study of nitride-bonded silicon carbide was carried out through an abrasive test conducted under various soil conditions. Results of this abrasive test demonstrated that wear on nitride-bonded silicon carbide was significantly less intensive than steels resistant to abrasive wear such as boron steel and C+ Cr + Nb padding weld, in all types of soil types tested; its wear rate being 9 times greater in heavy soil and 8 times greater in medium soil than that seen on nitride-bonded silicon carbido.