Patent ID: 6586046
Filing Date: 2003-07-01
Classification: C01P,C09C

Abstract:
A method for forming non-spherical aluminum-containing metallic particles to provide them with resistance to oxidation and corrosion, electrical insulation capabilities and sufficient brightness to provide heat reflectance and infrared radiation suppression, comprising the steps of:placing a preselected mass of non-spherical, aluminum-containing particles in a tube having an upper end open to the atmosphere and a sealed lower end having at least one sealed connection; placing the tube into a furnace; introducing a non-oxidizing, fluidizing gas into the tube through the at least one sealed connection at a flow rate sufficient to provide a positive flow of gas out of the upper end of the tube and to fluidize the particles within the tube so that the fluidized particles are within a heating zone of the furnace; then heating the furnace so that a temperature within the tube is within a preselected range; then introducing an oxidant gas at a preselected rate into the tube through the at least one sealed connection; and forming a thin protective ceramic shell over external surfaces of the non-spherical particles as the oxidant reacts with the metal, the ceramic layer characterized by transparency for improved reflectance of at least 60% and resistance-to-environmental deterioration.