Boron fiber or boron filament is an amorphous product which represents the major industrial use of elemental boron. Boron fiber manifests a combination of high strength and high elastic modulus.

A common use of boron fibers is in the construction of high tensile strength tapes. Boron fiber use results in high-strength, lightweight materials that are used chiefly for advanced aerospace structures as a component of composite materials, as well as limited production consumer and sporting goods such as golf clubs and fishing rods.[1][2]

One of the uses of boron fiber composites was the horizontal tail surfaces of the F-14 Tomcat fighter. This was done because carbon fiber composites were not then developed to the point they could be used, as they were in many subsequent aircraft designs.[3]

In the production process, elemental boron is deposited on an even tungsten wire substrate which produces diameters of 4.0 mil (102 micron) and 5.6 mil (142 micron). It consists of a fully borided tungsten core with amorphous boron.[4][5][6]

Boron fibers and sub-millimeter sized crystalline boron springs are produced by laser-assisted chemical vapor deposition. Translation of the focused laser beam allows to produce even complex helical structures. Such structures show good mechanical properties (elastic modulus 450 GPa, fracture strain 3.7%, fracture stress 17 GPa) and can be applied as reinforcement of ceramics or in micromechanical systems.[7]

References

  1. ^ Herring, H. W. (1966). "Selected Mechanical and Physical Properties of Boron Filaments" (PDF). NASA. Retrieved September 20, 2008.
  2. ^ Layden, G. K. (1973). "Fracture behaviour of boron filaments". Journal of Materials Science. 8 (11): 1581–1589. Bibcode:1973JMatS...8.1581L. doi:10.1007/BF00754893. S2CID 136959123.
  3. ^ "Boron fiber: The original high-performance fiber". www.compositesworld.com. Retrieved February 26, 2021.
  4. ^ Kostick, Dennis S. (2006). "Mineral Yearbook: Boron" (PDF). United States Geological Survey. Retrieved September 20, 2008.
  5. ^ Cooke, Theodore F. (1991). "Inorganic Fibers—A Literature Review". Journal of the American Ceramic Society. 74 (12): 2959–2978. doi:10.1111/j.1151-2916.1991.tb04289.x.
  6. ^ "Boron Fiber". Specialty Materials. Archived from the original on August 12, 2014.
  7. ^ Johansson, S.; Schweitz, Jan-Åke; Westberg, Helena; Boman, Mats (1992). "Microfabrication of three-dimensional boron structures by laser chemical processing". Journal of Applied Physics. 72 (12): 5956–5963. Bibcode:1992JAP....72.5956J. doi:10.1063/1.351904.
Category