Knowde Brand Summary
Identification
- Chemical Family
- Reinforcement Form
- Reinforcement Material
- Technologies
- Product Families
- Composite Materials Functions
With a filament tensile strength of 870,000 PSI, (6.0GPa) Astroquartz® pure silica has a higher strength-to-weight ratio than virtually all other high-temperature materials.
Astroquartz® fabrics and fibers are flexible and function well in applications subject to torsion and flexing. Astroquartz® is transparent to ultraviolet radiation above wavelengths of 2000A, and able to maintain this property at temperatures exceeding 750°C.
Astroquartz® (99.99% pure fused silica) is chemically stable, water-insoluble, and non-hygroscopic.
Halogens and most common acids have no effect on Astroquartz® products, with the exception of hydrofluoric and hot phosphoric acids. Astroquartz® products should not be used in environments where strong concentrations of alkalis are present.
Astroquartz® can be used at temperatures much higher than either E-glass or S-glass fiber ®, up to 1050°C.
Above 1050°C, slow devitrification or crystallization occurs with and accompanying loss of flexible mechanical properties. Exposure to alkalis may promote devitrification at somewhat lower temperatures.
Astroquartz® softens at approximately 1300°C but never liquefies. Volatilization begins near 2000°C. Because of their very high melt viscosity Astroquartz® products are often used in ablative composites.
Astroquartz® has a coefficient of thermal expansion close to zero in all directions (axial and radial), 0.54 x 10-6 cm/cm/°C. It is, therefore, an ideal reinforcement where dimensional stability under thermal cycling is critical. This low coefficient factor also provides great resistance to thermal shock, resulting in a product suitable for applications involving abrupt thermal variations.
The dielectric constant (3.7) and the loss tangent factor (0.0002) are the best to date among all mineral fibers, and these outstanding performance characteristics are maintained at high frequencies and high temperatures. For these reasons, this fiber is often considered the best choice for radomes and high-speed printed circuit boards.