Low-Cost Method for Metal Nano-Coating of Anisotropic Fibers

Physical Sciences, Inc. (PSI) has demonstrated the low cost fabrication of chopped carbon fibers with a 100 nm thick, continuous conductive copper coating for use as millimeter wave and infrared obscurants. The thickness, conductivity and surface roughness of the copper coating were controlled using a solution based electroless deposition process. Our best samples were found to significantly exceed the Phase I extinction coefficient target. PSI delivered 10 grams of these conductive obscurant microfibers to the Army. PSI fabricated carbon microfibers using an electropsinning based process. Using this process, PSI was able to fabricate carbon fibers with tunable diameters from 500 nm to 3 microns, with a diameter size distribution of about +/- 10%. We also examined two pilot scale sources of carbon fibers and then applied an electroless copper coating to them. The Phase II program will focus on the substrate microfiber type, source, mechanical properties, and production scaleup. The electroless copper adhesion, thickness and conductivity will be optimized and the process scaled-up to the multi-kg level. Microwave attenuation will be measured in an aerosol chamber and on single fiber obscurants during the proposed Phase II program.