NON-CHROMIUM CONTAINING BLACK MULTI-LAYER COATINGS

摘要

The disclosed invention relates to black multi-layer coatings for metallic substrates (1 ) or substrates having a metallic coating (2) and to articles covered, or partially covered with such coatings. The black coating consists of a black first layer (3) substantially comprised of nickel and a second polymeric silicate inorganic layer (4). The present invention may additionally have a third layer comprised substantially of organic constituents (5). This invention offers properties currently unavailable or insufficient in existing technologies. The present invention provides enhanced corrosion resistant, adherent black coatings which are thin enough to allow application to fasteners while providing a uniform black color, the combination of which have only been available previously with the use of hexavalent or trivalent chromium conversion coatings.