SCS Silicon Carbide Fiber
Specialty Materials' SCS silicon carbide fibers are the result of more than twenty years of research and development. These fibers are used in metal, ceramic and polymer matrix composites and are extremely effective for high-temperature applications. Silicon carbide reinforced titanium (TMC), aluminum (MMC) and ceramic composites (CMC) are high in strength and stiffness, lightweight, and maintain their properties at high temperatures.
Tests have proven that high fiber strength is maintained up to 1200°C in an inert gas atmosphere. SiC fibers do not react with typical matrix alloys. SCS-6™ - The lowest cost fiber, with high strength properties, wettability for metals, low electrical conductivity, high heat resistance, and corrosion resistance/chemical stability. SCS-Ultra™ - A fiber for the most demanding applications. Produced at the same diameter as SCS-6, it is 50% stronger and 10% higher in modulus.
Produced primarily in 5.6-mil diameter
Beta silicon carbide on (33μm) carbon monofilament
Smooth surface with duplex SiC/C coating
High strength / high modulus
Designed for use in metal-matrix composites
Successfully used in ceramic-matrix composites
Resistant to liquid-phase aluminum
Resistant to titanium bonding processes
Surface texture not optimum for interface with resin matrices
SCS-Ultra™ Silicon Carbide Fiber
SCS-Ultra™ silicon carbide fiber, a 1M psi tensile strength fiber was developed to meet the most demanding applications for aerospace materials. In the mid-1990s, turbine engine manufacturers wanted a fiber that could withstand the fabrication conditions of titanium aluminde to make a composite for use in rotating engine parts. Using its own resources, SMI developed SCS-Ultra™, a fiber with very fine silicon carbide crystallites (200 nm or less) that is 50% stronger and 10% stiffer than SCS-6 fiber and is stable at temperatures above 2500 deg F. Several high temperature titanium aluminide composite turbine engine parts were successfully developed using SCS-Ultra™ as the fiber reinforcement.
In addition to its outstanding effectiveness in titanium aluminide composites, SCS-Ultra™ is also extremely effective as a reinforcement for ceramic matrix composites. NASA Glenn Research Center has concluded that the most critical determinant for the high-temperature thermo-structural performance of a ceramic matrix composite is its creep-rupture strength, which in turn is highly dependent upon the creep resistance of the fiber. NASA has found that the most creep-rupture resistant fiber at high temperatures is the SCS-Ultra™ manufactured by Specialty Materials, Inc.
Produced primarily in 3-mil diameter
Beta silicon carbide on (33μm) carbon monofilament
Smooth surface with duplex SiC/C coating
Finer grain size results in the highest strength and modulus
Designed for use in titanium aluminide metal-matrix composites
Most creep-rupture resistant fiber for use in ceramic-matrix composites
Surface texture not optimum for interface with resin matrices
You can learn more about the use of SCS-Ultra™ in ceramic matrix composites here.
SCS Silicon Carbide Fiber Properties
| Property (Typical) | Units | SCS-6 | SCS-Ultra |
|---|---|---|---|
| Cross-Section | - | Round | Round |
| Aspect Ratio | - | Continuous | Continuous |
| Diameter | um | 142 | 75 |
| in.x10ˉ³ | 5.6 | 3.0 | |
| Density | g/cc | 3.08 | 2.89 |
| lbs/in³ | 0.11 | 0.10 | |
| Thermal Expansion | PPM/°C | 4.1 | 4.1 |
| PPM/°F | 2.3 | 2.3 | |
| Tensile Strength | MPa | 3,900 | 5,900 |
| ksi | 560 | 600-800 | |
| Tensile Modulus | GPa | 380 | 415 |
| msi | 56 | 50-54 |