BOR
Boron Fiber 4.0-mil
Specialty Materials ? BORON
Manufacturer page / TDSDescription
Continuous CVD boron monofilament with high compression strength and a textured surface that does not require sizing.. Product form: Continuous round monofilament. Official source: AF-SMI-BORON
Comparative overview
Boron fiber — Boron monofilament
Strengths: Exceptional axial stiffness, compressive performance and dimensional stability, especially valuable in metal-matrix and selectively reinforced structures.
When to use: Select for aerospace stiffeners, titanium/aluminum MMC, repair patches and compression/stiffness-critical components where price is secondary.
Key tradeoffs: Among the most expensive fibers; large filament diameter limits drape and the metallic core/coatings reduce electromagnetic transparency.
Qualitative ratings (1–10 scale)
| Relative cost | 10/10 — Very high — very low-volume CVD monofilament with specialized tungsten/carbon core production. |
|---|---|
| EM transparency | 3/10 — Poor — semiconductive/metal-core construction and high polarizability make it unsuitable for transparent radomes. |
| Temperature / fire resistance | 8/10 — Very high — high-temperature monofilament, though oxidation, interfaces and the matrix control usable service. |
| Impact / penetration resistance | 3/10 — Low — very high stiffness and large filament diameter produce low strain-to-failure and poor energy absorption. |
| Electrical / thermal conductivity | 6/10 — Moderate–high — moderate transport functionality: more conductive than dielectrics, far below pitch carbon or CNT yarn. |
| Specific tensile strength | 6/10 — 6/10 | 1532.6 kN·m/kg | Product TDS |
| Atmospheric durability | 7/10 — Good — relatively stable filament, but surface defects, core interaction and matrix/interface durability remain application-dependent. |
| Sustainability (CO₂e) | 2/10 — 100.00 kg CO₂e/kg fiber — Very high emissions — data quality: Low |
Technical properties
| Tensile strength | 4000.0 MPa |
|---|---|
| Tensile modulus | 428.0 GPa |
| Density | 2.61 g/cm³ |
| Filament diameter | 102.0 µm |
Applications and processing
Aerospace; space; aircraft repair; sporting goods; fusion and high-compression laminatesUnidirectional prepreg; filament placement; aerospace structural repair and hybrid laminate manufacture