Silicon carbide, also known as carborundum, is a hard chemical compound found only in trace amounts naturally; therefore it must be synthesized. Silicon carbide refractory ceramics have many applications within industrial production environments and it remains one of the most versatile refractory ceramic materials today.
Material characteristics such as corrosion resistance and high flexural strength make it suitable for low thermal expansion; only diamond and boron carbide surpass its strength in these respects.
Cost
Silicon carbide ceramics (commonly referred to as advanced, technical or engineered ceramics) stand out from other ceramic materials with their superior resistance to abrasion, corrosion and toughness, and high temperature mechanical properties. Fabricated from a complex blend of oxides, nitrides and carbides they must be processed using extremely specialized machinery and should only be used for specific applications.
Silicon carbide ceramics have become an increasingly sought-after engineering material. Silicon carbide boasts the highest corrosion and wear resistance of all nonoxide ceramics while providing thermal shock resistance and high temperature resistance, making it particularly desirable in applications that involve high temperatures, pressures or chemical attacks.
Silicon carbide offers excellent tribological properties at an economical price point; second only in hardness to diamond and significantly more affordable than boron carbide (B4C). Therefore, silicon carbide has become widely used both as an abrasive material (for grinding nonferrous metals and finishing tough/hard materials) as well as wear-resistant material in pump components and mechanical seals.
Refractories can also be used for applications in refractories applications, including burner nozzles, jet and flame tubes and other forms of combustion equipment that operate under extreme conditions. Refractory applications also include flue gas desulfurization plants and pipe manufacturing.
Corrosion
Silicon carbide (SiC) is one of the most frequently utilized nonoxide ceramics due to its superior corrosion resistance and hardness properties, making it perfect for mechanical seals and pump parts. Furthermore, SiC boasts exceptional thermal conductivity which enables it to retain strength even at very high temperatures; hence making it popular as brake pad material in consumer automobiles. Furthermore, due to its low thermal expansion and rigidity properties it makes an ideal material for abrasive applications such as metal cutting.
Corrosion of SiC occurs when exposed to fluid or gaseous environments that differ chemically from its bulk material, usually fluids or gases with differing chemical composition. Corrosive environments include both oxidative and acidic environments; typically seen with chemical processing operations like sodium sulfate corrosion at recession rates of one millimeter/year while basic slag corrosion produces rates up to 100 millimeters annually.
SiC corrosion is characterized by the formation of an oxide layer with different chemical composition than that found in bulk ceramic material, creating either passive or active oxidation depending on its environment; passive oxidation usually heals surface cracks while active oxidation creates new surface flaws, decreasing average flexural strength of ceramic and decreasing average flexural strength overall. Even so, corrosion rates for silicon carbide remain considerably lower than metals or other ceramic materials.
Hardness
Silicon carbide boasts a Mohs hardness of 9.5 and is one of the hardest industrial materials on the market; only diamond and cubic boron nitride are harder. Thanks to its hardness, coupled with exceptional chemical and thermal properties, silicon carbide makes an excellent high-performance material suitable for many high-performance applications such as aircraft engine parts. Furthermore, this versatile refractory ceramic can even be pressed into shapes or injection molded – making it an incredibly useful refractory ceramic option!
Silicon carbide differs from alumina in that it tolerates oxidation, making it ideal for use as both an abrasive and deoxidizer in metalworking. Furthermore, this material is easily press-formed into granular form before being melted at high temperatures, making it an excellent raw material for functional ceramics, advanced refractories and ballistic protection applications.
Ballistic capabilities depend on three characteristics of material – hardness, modulus of elasticity and compressive strength. Black-grey SiC ceramic is an effective ballistic protector due to its hardness, modulus of elasticity and compressive strength; when used for ballistic protection it reliably stops bullet penetration while dissipating any residual energy that remains. Due to its hardness and low mass it provides reliable defense with much lighter products than steel armour or aluminium oxide armouring can offer.
Mechanical properties of ceramic can be assessed through various tests, with Friedrich Mohs’ indentation test being one of the most reliable ones. This technique measures hardness by scratching it with an indenter, such as diamond.
Wear
silicon carbide offers superior mechanical properties when compared to alumina ceramics, making it more resistant to wear-and-tear, shock resistance, abrasion resistance and shock mitigation – hence making it more suitable for applications that demand tough conditions such as those found in industrial settings.
Silicon carbide ceramics feature superior thermal properties. They can withstand temperatures much higher than alumina ceramics, making them the ideal choice for use in high-performance applications where high heat resistance is key – for instance making machinable inserts for cutting hard-to-machine materials like superalloys and hardened steels.
Silicon carbide’s abrasive qualities make it suitable for wear-and-tear applications like grinding wheels. In fact, its Mohs hardness rating of 9.5 on the Mohs scale makes it more durable than aluminum oxide or other grains such as tungsten carbide.
Your choice of material depends on the needs and specifications of both your industry and project. Considerations including your environment, machining process and budgetary constraints will all play into this decision-making process. Knowing about each material’s particular advantages will enable you to select one suitable to your requirements – Saint-Gobain has an impressive variety of specialty products designed to fulfill those specifications across various industries.