What Are the Different Types of Silicon Carbide Bonds?

SiC is distinguished by a strong chemical bond between silicon and carbon that is both tetrahedral and covalent, providing it with exceptional hardness and versatility in properties.

Silicon carbide is an ideal material choice for parts that must withstand corrosion from chemicals, high temperatures and thermal shock, such as refractory parts.

Reaction Bonded Silicon Carbide

Reaction Bonded Silicon Carbide (RB-SiC) is an advanced ceramic material with high strength, excellent thermal and chemical resistance, and the capability of being formed into complex shapes. RB SiC is most frequently found in wear components for industrial applications like mechanical seals, bearings, pipe liners, flow control chokes and larger wear parts for mining cyclones; but can also be found as wear resistant coatings for walls and floors. Thanks to its very low coefficient of expansion it provides stability which allows it to be used where traditional metals cannot – meaning traditional metals would simply not work effectively in these settings.

Manufacturing process of RB-SiC involves injecting molten silicon into a porous carbon preform that has been packed into its desired shape. Once infiltrated, this reacts with carbon to form silicon carbide – this reaction may need to be modified depending on final product geometry, configuration and tolerance requirements. As opposed to sintered silicon carbide production lines, RB-SiC fabrication temperatures can range between 1500-1700C for easier fabrication of components with complex shapes than can be produced through standard sintering processes; however residue silicon remains within this material which limits performance when exposed to higher temperatures or corrosion environments.

For optimal RB-SiC characteristics, its silicon content must be reduced as much as possible. This can be accomplished by decreasing the amount of silicon added to preform, using lower melting point resin or by reducing how much of that silicon interacts with carbon during reaction process – otherwise an excessive percentage may result in cracking or microcracking when subjected to elevated temperatures.

Another way to enhance RB-SiC performance is by adding plasticizer. Plasticizer acts as a binding agent between silicon and carbon particles, producing stronger and denser structures than bare preforms. This feature can be particularly helpful for applications involving heterogeneous catalysts that need solid support structures; typical plasticizers include di-butyl phthalate, benzyl butyl phthalate, polyethylene glycol, polyvinyl acetate, methyl methacrylate, di-octyl phthalate and glycerol.

ALTRON(tm) Alumina Bonded Silicon Carbide

The ALTRON line of refractories provides superior oxidation and thermal shock resistance, helping customers lower operating costs. As non-wetting material, they can replace metallic components found in kiln furniture, waste incineration furnaces, aluminium reduction cells and copper shaft furnaces as well as providing good hot strength with moderate expansion; making them suitable as alternatives to conventional fire-clay refractories.

NB SiC boasts one of the highest hardness values among engineering materials. It is exceptionally tough and resistant to damage from heavy loads and impacts as well as abrasion from sharp particles or surfaces; furthermore it can withstand temperatures up to 1300 degrees C.

Material for this material is produced through a process called nitridation, in which a mixture of silicon carbide powder and a nitrogen-containing compound, such as ammonia or silicon nitride is heated under an inert gas to release its nitrogen molecules which react with silicon grains to form silicon nitride, binding them together to form dense and strong composite material.

Contrary to conventional fire-clay refractories, this invention presents a different approach in that its refractory does not contain free silica crystal phase as cristobalite; yet still boasts an exceptionally high silica content of up to 93% and thus greatly improving bonding between it and metal substrates.

It has also been demonstrated that this invention’s refractory can significantly improve dissimilar material joining between SiC and low-Si Al alloys by suppressing interfacial product formation, significantly increasing shear strength of joints to 28.8 MPa which is much higher than previously reported values for Al-SiC joints with lower silica content refractories.

The refractory produced through this invention is created by mixing a silica-alumina type refractory compound with fine aluminum powder, molding it, drying it and firing in an atmosphere with carbon oxide gas. As part of this process, silica in the refractory is reduced with aluminum to form metallic silicon while simultaneously carbonized into silicon carbide at Al-silicon carbide interface resulting in intergrowth textures including corundum and silicon carbide in its surface layer.

Purebide(r) Reaction-Bonded Silicon Carbide

Silicon carbide (SiC) is an inorganic material composed of silicon and carbon that has wide bandgap semiconductor properties. Found naturally as moissanite mineral, SiC has been mass produced as powder since 1893 for use as an abrasive and component in glass production. As a very strong material it can withstand extremely high temperatures while it may be doped with nitrogen, phosphorus or aluminum for electrical applications.

Pure silicon carbide is colorless; however, its industrial product often appears brown to black due to iron impurities. Tribological components made from this material have high strength and good dimensional stability as well as corrosion-resistance qualities; additionally, they can be produced in many shapes.

Reaction bonded SiC is used extensively across many industrial applications and can be produced using several processes such as Selective Laser Sintering (SLS) and reactive infiltration. Reaction bonded SiC typically starts as a mixture of SiC powders combined with carbon binder, before being infiltrated with molten silicon that reacts with carbon to form a ceramic material; typically this infiltrating metal is tungsten; however other metals like aluminium or molybdenum as well as alloys with silicon could also be infiltrating metals may also infiltrating this way.

SiC ceramic boasts superior wear resistance, thermal and chemical resistance, and dimensional stability, and comes in various shapes and sizes such as tubes, rods and cones for use in pumps, valves, mechanical seals and high temperature environments such as kilns or furnaces. It offers exceptional wear resistance as well as being highly dimensionally stable – characteristics that are especially helpful in components requiring high mechanical strength such as pumps. It has excellent wear resistance while still being thermal and chemical resistant and offers exceptional dimensional stability. It offers superior wear resistance in comparison to ceramic counterparts such as carbonized materials which come from silicon carbide crystallisation process in large quantity making SiC ceramic ideal for use in applications requiring high mechanical strength such as pumps valves mechanical seals as well as high temperature environments such as kilns or furnaces.

Reaction-bonded SiC is typically produced in a reaction kiln by infiltrating molten silicon into a porous carbon-containing preform of SiC powder. The resultant ceramic, known as reaction infiltration ceramic, can then be shaped and sintered like any other silicon carbide ceramics; however, due to lower temperatures it requires significantly less energy, making it suitable for creating intricate shapes in parts requiring complex shapes.

Purebide(r) Sintered Silicon Carbide

Silicon carbide (SiC) is an extremely hard and durable material with excellent corrosion, abrasion, heat and temperature resistance. Due to its ability to withstand oxidising conditions it makes SiC ideal for acid, caustic and corrosive environments as well as applications requiring pump seals, cutting tools, mixing nozzles and flame holders – as it reduces frictional temperatures in these situations by its higher thermal conductivity than many other materials.

SiC can be formed into dense, porous forms through reaction bonding or sintering processes, respectively. Reaction bonding involves infiltrating compacts containing mixtures of carbon and silicon with liquid silicon to bond individual particles of SiC together; while sintering involves heating the material at temperatures above its melting point with minimal application of pressure; this creates a composite with numerous carbon-graphite inclusions interspersed throughout its surface layer as a microstructure.

Graphite is an established lubricant, used in both carbon and silicon carbide materials to provide self-lubricating properties. Unfortunately, however, incorporating large amounts of graphite without cracking the microstructure or increasing porosity has proven challenging in sintered ceramic applications.

The present invention provides a dense, porous self-sintered silicon carbide/graphite composite which can be impregnated with lubricants to form material suitable for bearings and seals that survive dry running conditions, along with a method to produce such a composite.

The present invention employs a sintering process which produces a dense, porous body featuring a microstructure made up of carbon-graphite inclusions dispersed throughout its surface, silicon carbide matrix material and trace amounts of boron and free carbon as residual sintering aids. This material can then be impregnated with coke or charcoal as a lubricant to form a tribologically favorable compound; when tested against conventional self-sintered porous silicon carbide it performed significantly better and showed superior resistance against wear- and wear resistance as measured against conventional self-sintered porous silicon carbide material.