Silicon carbide (SiC) is an advanced ceramic with exceptional thermal shock resistance and strength properties, offering extreme hardness/wear resistance, low density, and chemical stability.
SiC is a nonporous material used for various abrasive applications, including grinding wheels and cutting tools. SiC can also be found in carborundum printmaking – an unconventional form of collagraph printmaking using carborundum grit to produce printed marks on paper.
Thermal Conductivity
Silicon carbide stands out among engineering ceramics as it possesses exceptional properties in terms of flexural strength, compression resistance and fatigue resistance. Furthermore, it features excellent chemical resistance properties as well as low thermal expansion properties.
Due to its low density, superior wear resistance, high abrasion resistance, and low coefficient of expansion, silicone rubber is used extensively in applications ranging from oil and gas pipelines to paper manufacturing, mining and atomic energy production. Furthermore, bullet-proof plates and nozzles made from this material are often found within aerospace and automotive industries.
Aluminum Nitride (AlN) ceramics offer higher electrical conductivity but require more costly materials for production, which limits their widespread application in electronics.
Due to these benefits, yttria-stabilized zirconia has become an increasingly popular material choice in a wide range of fields. This is particularly evident given that it provides superior electrical and thermal conductivity while still boasting the superior mechanical properties associated with silica-based ceramics.
Corrosion Resistance
Silicon carbide is a highly corrosion-resistant material. It stands up well to most chemicals, steam and water at both high and low temperatures – making it suitable for environments in which other materials might fail. Furthermore, silicon carbide offers outstanding thermal stability as well as exceptional mechanical strength.
Silicon carbide ceramics have the qualities necessary to be an ideal material choice for applications requiring resistance against wear and tear, such as components, refractories and ceramics; electrical applications (electronic insulation); high-temperature mechanical applications like furnace linings, combustion chamber rings and gas turbines. Furthermore, silicon carbide ceramics can be found in aerospace engineering, automobile production facilities, chemical plants and energy engineering applications.
Silicon carbide ceramics offer exceptional tensile strength, resistance to thermal shock, chemical attack and abrasion as well as thermal shock protection, making them suitable for ballistic protection against 7.62 x 54mm R B32 AP projectiles travelling up to 850m/s; making them an attractive alternative to boron carbide used in bulletproof armor systems.
Electrical Conductivity
Silicon carbide stands out among industrial ceramics as one of the most versatile, with an exceptional range of thermomechanical properties that span multiple sectors and applications. Notably, its ability to retain strength even at elevated temperatures while resisting thermal shocks underscores its unique value as a material suitable for demanding applications across numerous fields.
SiC is typically an electrically semiconducting material with band gap energies ranging between 2.4 eV and 3.4eV depending on its polytype, yet second phase additives that create pathways through its structure can dramatically enhance its electrical conductivity.
The volume resistivity of porous SiC can be adjusted by altering its chemical composition and processing conditions during sintering, or through its porosity and microstructure – increasing porosity leads to reduced cross-sectional areas for charge carrier transport, leading to decreased volume resistivity.
Doping porous SiC with acceptors or donors that introduce electrons or holes into its semiconductor structure can enhance its electrical conductivity, significantly decreasing resistance while making it suitable for heaters or electrical components.
Hardness
Silicon carbide ceramics are one of the hardest non-oxide ceramic materials, second only to diamond, cubic boron nitride and boron carbide. Due to its combination of high hardness with low density and superior corrosion resistance, silicon carbide ceramics make an excellent material choice for mechanical seals, pump parts, structural ceramics and ballistic armour applications. Silicon carbide ceramics retain strength even at high temperatures while resisting oxidation more effectively than other ceramic materials.
IPS ceramics can withstand the extreme pressure and temperature conditions found within a gas turbine without cracking, creeping or deforming under extreme circumstances. Furthermore, these materials offer excellent acid/lye resistance as well as chemical stability.
An impact test can be used to accurately assess the hardness of material samples. A spring is used to accelerate a spherical, tungsten carbide-tipped mass which hits against a surface sample. As its energy dissipates upon impact with its sensor recording each energy loss as the mass strikes the sample’s surface, indentation depth or size provides insight into hardness measurement; this technique is known as rebound hardness testing. This test also serves as one way of testing abrasion resistance.
Wear Resistance
Silicon carbide ceramics have been engineered to withstand extremely high temperatures without losing strength, making them the perfect material for wafer tray supports and paddles in semiconductor furnaces. Furthermore, this material’s excellent chemical resistance means it can also be utilized for electrical applications like thermistors and varistors.
Porous nitride-bonded silicon carbide wear resistance depends on the type of soil mass and grain size distribution, with resistance decreasing as more abrasive particles enter soil masses; in light soils micro-cutting dominates, while medium and heavy soils favor furrowing as the dominant mode of abrasion.
Nitride-bonded silicon carbide offers outstanding abrasive and impact resistance due to its low coefficient of friction, resistance to heat and thermal expansion and vibration-proof properties. As such, this material makes an ideal material for applications that demand high abrasion resistance at elevated temperatures such as lining kilns and resistance furnaces; coating surfaces in harsh environments or vibration; as well as containers for bulk materials like abrasive powders and granular materials stored at extremely high temperatures; pipes transporting these materials at very high temperatures; crucibles used for melting aluminium; and grinding wheels.