Silicon carbide ceramic fibers are essential elements in lightweight, high-performance ceramic matrix composite (CMC) materials. They improve strength, stiffness, thermal stability and oxidation resistance.
NASA’s Glenn Research Center has unveiled an innovative microwave processing method to rapidly create stronger SiC tows with tailored specifications while healing damaged fibers, increasing implementation in aerospace applications as well as other extreme environments.
High Temperature Resistance
Silicon carbide ceramic fibers boast high stability and retain their strength even at higher temperatures, making them an excellent option to replace tungsten or carbon filaments in metal matrix composite materials, improving performance in elevated operating temperatures.
Silicon carbide fibers have the ability to help minimize ceramic brittleness while increasing damage tolerance – this makes them an excellent choice for aerospace applications that must withstand harsh environments and extreme conditions.
Silicon carbide ceramic fibers stand out as superior choices due to their lower fracture stress than that of alumina filaments, making it easier to incorporate them in composites operating at elevated temperatures and their increased tensile strength at such temperatures.
Tyranno(tm) SA-9 and SiC-14 fibers exhibit over 94% retention of their tensile strength after being heated at 1900degC for 1 hour in an atmosphere containing argon, which demonstrates their excellent thermal stability. Furthermore, EDS analysis (Fig 9) confirms the significant increase in carbon content on their surfaces due to heat treatment.
BJS Ceramics GmbH is currently creating a pilot plant to produce large scale high performance SiC fibers at scale. This will mark Europe’s first pre-industrial pilot plant for ceramic fiber reinforced composites and provide the final step to an integrated value chain.
High Strength
Silicon carbide ceramic fibers are much stronger than their oxide counterparts, making them an excellent option for reinforcing ceramic matrix composite (CMC) materials and providing extended protection from hostile environments and high temperatures. Silicon carbide ceramic fibers also boast superior antimicrobial capabilities making them suitable for applications requiring protection from aggressive environments or high temperatures for an extended period of time.
At present, one of the major hurdles to short SiC fiber production has been an inefficient production method that’s cost-effective and time-effective. Existing methods can only produce few kilograms a month and often take months before producing an entire batch. With this SBIR topic we aim to develop more commercially viable processes for producing shaped fibers.
Research team is developing a process for fabricating silicon carbide (SiC) fibers from organosilicon precursor using low temperature gas-solidification pyrolysis. The technology allows fabrication of SiC fibers with various compositions and shapes, permitting production of various ceramic matrix composites as well as high degrees of customization to fit specific applications.
NASA has pioneered SiC/SiC ceramic matrix composite (CMC) technologies as an essential means to advance aerospace, automotive, power generation and other industries operating under extreme environments. Utilizing non-oxide SiC fibers and matrices with superior structural properties for providing hot components with lasting structural solutions at elevated temperatures for prolonged operation.
High Stiffness
Silicon carbide ceramic fibers feature high stiffness and can maintain their strength under intense pressure, making them an ideal material for applications including engine components, as well as abrasive machining processes such as grinding, sanding and water jet cutting. Silicon carbide ceramic fibers have also found wide use in modern lapidary, where their durability and affordability make them a favorite material choice.
Silicon Carbide Fibers can be identified by their presence of carbon and silicon molecules within a polymer matrix and dispersed grains of g-alumina. Produced through pyrolysis of organic precursors into inorganic ceramics, common commercial silicon carbide fibers include continuous alumina-silica mullite (Nicalon) and discontinuous alumina-silica (Tyranno or Sylramic) ceramic fibers; their stiffness increases with mixed bonding between carbon atoms bonded to oxygen or silica molecules – their Young’s modulus ranges from 205 to 215GPa respectively.
Silicon carbide fiber-reinforced ceramics exhibit greater damage tolerance than monolithic ceramics due to moderate bonding forces between fibers and matrix materials, as well as adaptable interphases that form during processing. Microstructure analysis using optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy confirm this behavior as damage-tolerant behaviour is observed. Furthermore, these composites also boast superior corrosion resistance and thermal stability properties in addition to excellent mechanical properties.
High Wear Resistance
Silicon carbide fibers are highly resistant to wear in harsh environments. Their exceptional wear resistance allows them to withstand much higher stresses than traditional ceramics while offering improved corrosion protection, strength, stiffness and high temperature oxidation resistance make this material suitable for aerospace applications like jet engine parts and rocket nozzles.
Woven silicon carbide fibers find many uses in textile-reinforced composites, particularly ceramic matrix composites (CMCs), which combine reinforcing material dispersed throughout a ceramic matrix matrixe. CMCs can be manufactured through various processes – injection molding, pultrusion or direct compression are among them – but are often utilized in aerospace applications such as gas turbine engines and heat shields due to their excellent wear and temperature resistance.
Sylramic SiC fiber developed at AFRL has proven its superior wear properties compared with commercially available sic fibers, making it suitable for use in demanding aerospace applications such as nozzles and rocket engine components. Pin-on-disc friction tests were used to demonstrate its abrasion resistance, investigating the tribological behavior of SiC/SiC based materials under dry conditions. Results demonstrated that the tribological properties of these materials depended heavily on surface processing as well as type and severity of applied loads, with sintered nitride-bonded SiC fibers being an ideal reinforcement choice for creating advanced composites that offer increased wear properties and better fatigue resistance.