Boron Fiber
Produced in single-filament reactors by chemical vapor deposition. Boron fiber exhibits a unique combination of high compression strength, high modulus and large diameter.
Boron Fiber is produced in single-filament reactors by chemical vapor deposition, boron fiber exhibits a unique combination of high compression strength, high modulus and large diameter. It provides superior compression properties compared to carbon fiber based composites.
Elemental boron is deposited on a fine tungsten wire substrate and produced in diameters of 4.0-mil (102-micron) and 5.6-mil (142-micron). The resulting fiber is essentially amorphous boron with a fully borided-tungsten core.
The textured surface provides an excellent interface in resin-matrix composites, eliminating any need for sizing treatments. Primarily used in resin-matrix composites it is available as a unidirectional prepreg tape with 250ºF and 350ºF cure epoxies.
Boron Fiber Properties
| Property | Units | 4-mil Boron (Typical) | 5.6-mil Boron (Typical) | 3-mil Boron (Typical) |
|---|---|---|---|---|
| Diameter | um | 102 | 142 | 76 |
| in.x10ˉ³ | 4 | 5.6 | 3 | |
| Cross Section | Shape | Round | Round | Round |
| Density | g/cc | 2.61 | 2.48 | 2.82 |
| lbs/in³ | 0.094 | 0.089 | 0.102 | |
| Thermal Expansion | PPM/°C | 4.5 | 4.5 | 4.5 |
| PPM/°F | 2.5 | 2.5 | 2.5 | |
| Tensile Strength | MPa | 4,000 | 4,000 | - |
| ksi | 580 | 580 | - | |
| Tensile Modulus | GPa | 428 | 400 | - |
| msi | 62 | 58 | - | |
| Compression Strength (est.*) | MPa | >6,000 | - | - |
| ksi | >900 | - | - | |
| Hardness | Knoop | 3,200 | 3,200 | 3,200 |
*Filament compression strength calculated from composite lamina property and back-out factor.
Unique Properties of Boron Fiber Composites
•No other composite material has higher compressive strength properties than Boron fiber & Hy-Bor® fiber composites
•Adding Boron fiber to composites with standard & intermediate modulus fibers will increase the tensile & compression modulus allowing reduced thickness/ply count for equivalent stiffness
•When using Hy-Bor®, a designer can reduce the laminate thickness resulting in higher performance at a lower mass
•Hy-Bor® can reduce manufacturing costs & result in a net cost savings
• Reduces processing steps like debulking
• Reduces layup time due to lower ply count
•Hy-Bor® is used in space applications like the Google Earth Cameras because its zero CTE & High Elastic Modulus
•Boron & Hy-Bor® prepreg can be manufactured with epoxy, toughened epoxy, cyanate ester, cyanate siloxane, bismaleimides, phenolic & polyimide resins
•No galvanic corrosion with boron fiber
