Silicon Carbide ceramic is an non-oxide dense refractory ceramic material offering many desirable properties and has become a top choice in numerous industrial markets worldwide. Foamed SiC ceramics are highly recommended for the filtration and purification of industrial lyes and metal solutions, heating of corrosive liquids and as special carrier materials in automotive exhaust gas purifiers.
Thermomechanical properties
Silicon carbide ceramics are well known for their outstanding abrasion, corrosion, impact and thermal resistance properties – qualities which make them the perfect material choice for applications requiring durability such as mechanical seals and bearings. Silicon Carbide, composed of silicon and carbon, is an extremely hard chemical compound with an extremely hard Mohs hardness rating of 9. It occurs naturally as moissanite gemstone; however, commercial production began as powder and crystal forms since 1893 for use as an abrasive. Refractories also use ceramic fiber for burner nozzles, jet and flame tubes, flue gas desulphurisation plants, petrochemical production facilities, bulletproof plate production and flue gas desulphurisation facilities. Ceramic fibre has the unique combination of toughness, strength and weight savings over steel and aluminum oxide materials; making it an attractive material choice when looking for bulletproof plates.
SiC ceramics can be enhanced in terms of their abrasion and impact resistance by adding additives. Sintering bonds ceramic particles together using a molten silicate liquid, creating polycrystalline structures with high specific surface areas. When oxides or metals are added during this process, bond strength increases, leading to improved abrasion resistance as well as corrosion resistance benefits.
Corrosion of SiC ceramics is an intricate process that depends on multiple factors: chemical species used, temperature and reaction history of their attacker. Corrosion behavior of ceramics typically depends on its nature of attack; often indicated by either recession rate or performance loss over time. Any loss in strength may be gradual or sudden depending on the attack type and underlying microstructure.
Erosion characteristics of ceramics can be significantly affected by impurities, sintering aids, grain boundary phases and porosity. For example, SiC corrosion in acidic slag environments is characterised by surface pitting and erosion of its amorphous phase, with either active oxidation reducing flexural strength averages or passively replaced by oxygen in the slag increasing them flexural strengths of SiC ceramics.
Corrosion resistance
Silicon carbide is one of the hardest and lightest engineering ceramics. Distinguished for its exceptional corrosion resistance, which surpasses most other ceramic materials. Silicon carbide’s robust properties also allow it to withstand aggressive chemicals and temperatures; with high tensile strength and modulus of elasticity. Silicon carbide has many applications within mechanical seals, pumps and bearings applications as well as blasting nozzles and pipes abrasives use.
SiC’s corrosion resistance can be attributed to its microstructure and preferred orientation, particularly its micro-powder structure. SiC is more resistant than other materials to acidic environments due to its stratified columnar structure’s higher corrosion resistance compared with faceted crystal structures and has superior (111)-oriented films than (220)-oriented ones.
Silicon carbide ceramic offers resistance against slag attack and has excellent oxidation resistance, making it a good material choice for bearings subject to high temperatures and chemical attacks. Furthermore, due to its low coefficient of friction it makes an ideal material choice for aerospace components as it’s hardness and ability to dissipate energy make it suitable as armor while still offering increased protection against ballistic threats. Silicon carbide’s lightweight nature also makes it comfortable when worn comfortably while offering enhanced ballistic protection.
Silicon carbide ceramics offer excellent corrosion resistance but can be fragile and crack easily. New fabrication processes have the ability to improve fracture toughness allowing manufacturers to create resilient yet cost-effective silicon carbide ceramics.
Silicon carbide can be formed using either reaction bonding or sintering in order to achieve the desired microstructure. Each process has an impactful impact on its final microstructure; reaction bonded SiC is typically created by injecting liquid silicon into compacts of coarse SiC and carbon mix using infiltrating equipment; this allows silicon atoms to react with carbon to produce more SiC which can then be sintered at high temperatures into dense ceramic. Both methods result in ceramics with differing porosities and densities which affect their applications respectively.
Wear resistance
Silicon carbide ceramic is an extremely hard and resilient material designed to withstand extremely abrasive environments without succumbing to deformation or softening, high temperatures without losing strength or hardness and chemical corrosion. It makes an excellent choice for applications involving critical component protection such as inner sleeves in powder grinding beds, ball mills and crushing equipment. Manufactured from high-purity raw materials through pressing, sintering and mechanical processing steps, it boasts many advantages such as its resistance to chemical corrosion resistance as well as high wear resistance – saving energy costs while increasing production efficiency.
Sintered silicon carbide ceramics feature low coefficient of thermal expansion (CTE) and high Young’s modulus values that make it suitable for use in harsh environments, including those exposed to harsh chemicals or thermal shock. Due to its resistance against abrasion and erosion, sintered silicon carbide ceramics have also found application in mills, expanders, extruders and burner nozzles – as well as in refractory applications like flue gas desulphurisation plants.
As a material with excellent abrasion resistance, stainless steel stands out thanks to its hard texture and grain size distribution; further enhanced through nitriding and densification processes. Furthermore, its impact strength and friction wear resistance make it an excellent material choice for bearings and mechanical seals used in acidic and hot water/steam applications.
Although its performance is outstanding, it does have its limitations. For instance, its resistance to brittle cracking is limited by its relatively low compressive strength; and hardness and modulus of elasticity limit its resistance against bending and stretching. However, recent advances in graphene and zirconium composite technologies provide promising new avenues for the application of this multipurpose material across a range of fields. Innovative materials combine the properties of SiC with those of polymers to provide enhanced tensile strength and elastic properties, opening up exciting applications in 3D printing, ballistics and protective armour design. Manufacturers will now have greater protection at lower weight than ever before allowing for increased protection levels without increasing product weight significantly.
Thermal conductivity
Silicon carbide ceramic is highly heat resistant nonoxide ceramics commonly employed in products requiring both strength and temperature resistance. Silicon Carbide has become an invaluable choice for use in mechanical seals, pump parts, mechanical seals, seal ring backers and pump parts due to its hardness, excellent thermal conductivity and low coefficient of thermal expansion – these properties make it suitable for applications with substantial changes in size over time. Silicon Carbide also plays an integral part of automotive brake pads due to both strength and thermal conductivity being required in their performance – making this material essential in providing proper performance of automotive brake pads which requires both qualities in order for them to perform correctly.
Addition of a small amount of graphene can dramatically improve the mechanical properties of SiC ceramics, particularly flexural strength. However, its effect will depend on their method of production and grain size; furthermore, this addition reduces abrasion resistance and surface friction of ceramics.
Silicon carbide ceramic plates are significantly lighter than their steel counterparts, giving wearers greater freedom while providing effective ballistic defense. Furthermore, silicon carbide ceramic armor helps decrease weight and can positively impact fuel consumption and range.
SiC, in its pure state, is an electrical insulator; however, doping it with specific impurities can result in semi-conductivity. Care must be taken during the doping process to achieve semi-conductivity; too large of an impurity dose could produce negative electrical behavior while too few can inhibit electricity transfer altogether. Low-pressure plasma nitriding can help create electrically conductive SiC by applying it across an entire ceramic surface or just to one region, providing an economical and quick way of reaching desired results.