Nickel Nanostrands™ Expand Nanotechnology Engineering Capabilities

Researchers at the Air Force Research Laboratory Materials and Manufacturing Directorate, working with Metal Matrix Composites of Heber, Utah have developed a new form of nano-structured nickel that dramatically expands nanotechnology design engineering capabilities. The new materials are called nickel nanostrands™ and were developed under Phase I of an Air Force Small Business Innovation Research (SBIR) program. Nickel nanostrands are strands of sub-micron diameter nickel particles linked in chains, microns to millimeters in length. They are very similar to carbon nanofibers but provide the additional properties of nickel, significantly expanding the variety of options available for developing tomorrow's nanostructure technologies.

Nickel nanostrands can be engineered to meet the diameter and length specifications in many fields of sub-micron and nanostructure design. Diameters ranging from 50 nanometers (nm) up to two microns have been produced, with aspect ratios generally in the 50:1 to 500:1 range. Researchers hope to produce nanostrands in the range of 10-30 nm in diameter. Further development could lead to advancements in nanotechnology directly benefiting the Air Force, aerospace community and industry at large.

Nickel nanostrands are analogous to carbon nanofibers (or multi-wall carbon nanotubes) but bring the additional electromagnetic, chemical, catalytical and metallurgical properties associated with nickel to the nanostructure design engineer's toolbox. These new materials have already demonstrated their utility in creating conductive resins, paints, adhesives and thermoplastics for a wide range of conductive polymer and conductive composite applications. Researchers at Metal Matrix Composites, for example, have created paints with a sheet resistance less than 1 ohm per square, and adhesives and thermoplastics with conductivities of 40 S/cm (Siemens per centimeter) and 150 S/cm, respectively.

Nickel nanostrands can also further enhance the conductivity of fiber or particle reinforced composites, thus providing a three dimensional conductive lattice in the otherwise insulating polymer resin matrix. A loading of only two percent of volume in an otherwise standard prepreg, for instance, doubles the conductivity of a carbon fiber composite. This is important for the Air Force and industry because infiltrated carbon composites have proven highly useful in lightning strike protection for aircraft and other composite structures.

Additionally, when nickel nanostrands are added to elastomers, the resulting composite material exhibits remarkable changes in conductivity with respect to tensile or compressive strain. Since nickel nanostrands are a magnetic material, they may be magnetically aligned, while the carrier is still in the liquid phase, yielding a whole range of unique applications, such as magnetically oriented inks or magnetically aligned conductive fibers. The unique microstructure and chemistry of nickel nanostrands could also lead to important advancements in filtering, catalysis, energy storage and nanometallurgy.

Though nickel nanostrands are similar to carbon nanofibers in terms of size and shape, their anticipated applications are quite different, and the simple but proprietary chemistry by which they are produced will no doubt result in a volume production pricing comparable to other nickel commodity powders.

If you would like further information regarding this Success Story, please email our Technical Information and Support Center (TISC) at techinfo@afrl.af.mil, or call them at (937) 255-4689.