Silicon carbide ceramic fibers exhibit exceptional resistance to oxidation and high thermal stability, making them excellent reinforcement materials for ceramic matrix composites (CMC), polymer matrix composites, and metal matrix composites.
Nicalon crystalline SiC fiber offers improved performance to ceramic, polymer and metal matrix composites in short or long continuous tow forms.
High-Temperature Resistance
Silicon carbide ceramic fibers have long been utilized as reinforcement in metal matrix composite materials due to their exceptional temperature resistance. Furthermore, this material offers great promise as an advanced bulletproof plate material and bearing material, both being suitable for harsh environments that must withstand high temperatures and extreme environments.
Refractory ceramics used in high temperature applications must withstand creep deformation under constant load to be suitable. This depends on their capacity to withstand creep deformation due to effective matrix strain rate versus effective fiber strain rate, which in turn depends on free carbon concentration within their preforms; Nicalon fibers produced via chemical vapor deposition (CVD) or spinning confine their free carbon to specific regions known as segregation areas for easier testing and monitoring.
Restricting silicon carbide ceramics has proven to improve their performance when used in metallic matrix composites (CMCs). CMCs created from these ceramics boast high abrasion resistance, stiffness, hardness and thermal stability as well as their low density and superior ballistic characteristics which further contribute to improving their performance.
Researchers at Wright-Patterson Air Force Base have developed and commercialized a process for producing short silicon carbide ceramic fibers that can be integrated into weaving or braiding systems to produce high strength ceramic matrix composites suitable for gas turbine engine components and other aerospace applications. These ceramic fibers, known as Sylramic and its derivative Sylramic-iBN have shown to perform exceptionally well during tests that mimic engine conditions.
Low Density
Silicon carbide ceramic fibers feature an extremely low density, making them strong yet lightweight, which enables them to improve the performance of materials such as metals, polymers and ceramic matrix composites (CMC, PMC, MMC). Utilizing SiC fibers can increase strength, corrosion resistance, thermal stability and wear resistance as well as decrease weight compared to using nickel-based superalloys – ideal for aerospace applications compared to which silicone carbide ceramic fiber reinforced components may be up to two times stronger and 20% more heat resistant while being two thirds lighter compared with using nickel-based superalloys.
Over the past 30 years, three generations of small diameter ceramic fibers based on silicon carbide have been developed over time. The first was invented and commercialized by Nippon Carbon in 1983 using organosilicon polymers converted to ceramics through pyrolysis; second-generation silicon carbide fibers featured reduced oxygen content through irradiation and curing under an oxygen-containing atmosphere; while third generation silicon carbide fibers produced via carbothermal reduction using carbon monoxide as starting material have near stoichiometric composition with higher crystallinity; while carbothermal reduction using carbon monoxide as starting material produces near stoichiometric composition with higher crystallinity than their predecessors.
The global market for silicon carbide ceramic fibers can be divided into several segments according to form and usage. Continuous silicon carbide fibers hold the largest share in terms of both usage and market size, due to their applications involving radiation resistance, superior strength, metal matrix composites and weight saving properties that make them more economical than other metallic alloys.
High Stiffness
Silicon carbide fibers retain their high stiffness even at elevated temperatures, making them an excellent reinforcement material in metal matrix composite materials. Furthermore, they exhibit excellent chemical corrosion, oxidation and fatigue resistance characteristics – ideal characteristics for aerospace applications.
Conventional reinforcement materials like carbon or boron fibers quickly lose strength and stiffness when exposed to elevated temperatures, limiting their use in high-temperature applications such as aerospace. Silicon carbide ceramic fibers on the other hand have maintained their mechanical properties at these elevated temperatures allowing them to be utilized in applications including aerospace, military weaponry and equipment, advanced sports equipment and automobiles.
Silicon carbide ceramic fibers are easier and more affordable to produce than their boron counterparts, offering superior specific strength, stiffness, thermal expansion coefficient, electrical conductivity and electrical conductivity – making them an excellent reinforcement material for high temperature composite materials.
Whisker-based and continuous silicon carbide fibers can both be used for reinforcing high-temperature composite materials, although their tensile strengths vary considerably based on composition and microstructure of bulk materials. Research has indicated that increasing bulk species concentration leads to decreased tensile strength; this corresponds with their decomposition into SiCxOy amorphous phase when exposed to elevated temperatures. To improve continuous fiber’s tensile properties it is crucial that their fracture mechanism and structural stability at such temperatures be studied thoroughly.
Excellent Wear Resistance
Silicon carbide ceramic fibers’ excellent wear resistance makes them the perfect material for reinforcing metal and ceramic matrix structures. These high-performance materials can also provide superior strength and toughness at very high temperatures while offering chemical corrosion resistance.
Silicon carbide ceramic fibers boast superior performances over carbon or boron fibers in terms of specific strength, stiffness, thermal expansion coefficient and thermal conductivity – which makes them easier to produce qualified metal matrix composite materials (CMC). CMC materials may be named according to fiber/type matrix combinations like C/SiC for carbon-reinforced SiC or their manufacturing process such as liquid polymer infiltration or chemical vapor infiltration.
These new lightweight ceramic materials are revolutionizing their application in various fields such as aerospace, energy and power, metallurgy, chemical and other demanding industries, thanks to their low density, stiffness, chemical resistance and tensile strength as well as resistance against extreme temperatures.
Metal matrix composites that incorporate these materials are widely utilized due to their resistance to corrosion, oxidation and fatigue. Furthermore, these materials can also be used in manufacturing ceramic components for gas turbines and aero-engines. In the petrochemical industry these corrosion-resistant containers and pipelines contain chemicals like sulfuric acid or hot sodium hydroxide solutions; in automotive industries they may be found as valves, bearings and mechanical seal parts.