Physical Vapor Deposition (PVD) as a Method to produce High Aspect Ratio Conductive Flakes for Advanced Bispectral or Infrared (IR) Obscuration

This Phase I STTR proposal addresses the development of a low cost electrically conductive obscurant, with functionality in the visible and IR spectra. A commercial low-cost state of the art PVD process that is currently used to manufacture aluminum nanoflake will be adopted to produce copper nanoflakes with surface interference layers designed to produce conductive flakes that have a black appearance. The black interference colors will be produced by forming nanothick oxide and semiconducting layers of the copper flake surface. Attempts in the past to form nanothick copper flakes with a well-controlled diameter failed due to the ductility of the copper flakes. More recently a new diminution method has been developed that causes the copper flake to become brittle during the size reduction step. Pure copper nanoflakes and flakes with optically functional surface layers will be evaluated with thicknesses ranging from 5nm to 25nm and a target diameter of 3m. The Phase I development will be performed in a pilot scale PVD/CDV/Polymer deposition system, the function of which is duplicated by a large-scale production system. The proposed project is a collaborative effort between Sigma Technologies and Clarkson University.