Patent ID: 9315902
Filing Date: 2016-04-19
CPC Classification: C23C

Claim Text:
1. A composition for chemical conversion treatment for use in forming a black film having an L value of less than 28 on a metallic surface of a member, consisting of: a trivalent chromium-containing substance; at least one cobalt-containing substance; at least one sulfur compound, which is an organic compound; an organic phosphonate compound consisting of one or more compounds selected from the group consisting of organic phosphonic acids, ions of organic phosphonic acids, and organic phosphonates, an additional component selected from the group consisting of nickel-containing compounds; tellurium-containing compounds that release tellurium ions or oxygen acid ions of tellurium; nitrogen-containing compounds; ions of metals selected from the group consisting of Ni, Na, K, Ag, Au, Ru, Nb, Ta, Pt, Pd, Fe, Ca, Mg, Zr, Sc, Ti, V, Mn, Cu, Zn, Sn, Y, Mo, Hf, Te, and W, which may be in a form of oxygen acid ions thereof; aqueous substances containing zinc; substances forming anions of inorganic acids selected from the group consisting of halogen acids, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, and inorganic acids including phosphorous selected from the group consisting of orthophosphoric acid, polyphosphoric acid, metaphosphoric acid, pyrophosphoric acid, ultraphosphoric acid, hypophosphorous acid, and perphosphoric acid; pH adjusting materials selected from the group consisting of sodium hydroxide, sodium hydrogen carbonate, ammonia, sulfuric acid, nitric acid, and hydrochloric acid; surfactants; colorants; pigment-producing agents; desiccants; plastic dispersive materials; dispersants; polyphenols; and combinations thereof; and a solvent selected from the group consisting of water and a combination of water and a water-soluble organic solvent, wherein a content ratio (S/P) of the organic sulfur compound relative to a content of the organic phosphonate compound in the composition is in a range from 0.1 to 10, wherein a content of the trivalent chromium-containing substance in the composition is in a range from 1 to 10 g/L in chromium content equivalent, a content of the cobalt-containing substance in the composition is in a range from 0.1 to 10 g/L in cobalt content equivalent, the content of the sulfur compound in the composition is in a range from 0.1 to 10 g/L, and the content of the organic phosphonate compound in the composition is in a range from 0.1 to 20 g/L, and wherein upon forming the composition as a film onto a metallic surface, the film has an L value of less than 28 when the film is formed by immersing the metallic member in the composition having pH of 2.2 for 45 seconds, and the L value is measured according to JIS Z 8722.