Materials for, and methods of, colorizing a metallic surface with micro-gratings using vibration cutting technologies are provided. Micro-gratings on aluminum, brass, and stainless steel surfaces can be rapidly created to effect, under illumination, at least one color observable in the visible spectrum using elliptical vibration texturing, a vibration-assisted mechanical cutting process. The modified metallic surface can display multiple visible colors, an iridescent effect caused by changes in one or more cutting parameters employed to produce the micro-gratings, the angle of illumination by an incident light, and/or the viewing angle of the surface under illumination.

Materials for, and methods of, colorizing a metallic surface with micro-gratings using vibration cutting technologies are provided. Micro-gratings on aluminum, brass, and stainless steel surfaces can be rapidly created to effect, under illumination, at least one color observable in the visible spectrum using elliptical vibration texturing, a vibration-assisted mechanical cutting process. The modified metallic surface can display multiple visible colors, an iridescent effect caused by changes in one or more cutting parameters employed to produce the micro-gratings, the angle of illumination by an incident light, and/or the viewing angle of the surface under illumination.

The present inventions refers to a passivation composition for depositing a chromium-comprising passivation layer on a zinc or zinc-nickel coated substrate, the composition comprising: (i) trivalent chromium ions, (ii) at least one complexing agent for the trivalent chromium ions, being different from the at least one corrosion-inhibiting agent, and (iii) at least one corrosion-inhibiting agent, which is (A) one or more than one substituted azole compound and/or salts thereof, together in a total concentration below 10 mg/L, based on the total volume of the passivation composition, and/or (B) one or more than one unsubstituted or substituted aliphatic organic acid with at least one mercapto-group and/or salts thereof, together in a total concentration in a range from 0.001 mg/L to 100 mg/L, based on the total volume of the passivation composition.

The present inventions refers to a passivation composition for depositing a chromium-comprising passivation layer on a zinc or zinc-nickel coated substrate, the composition comprising: (i) trivalent chromium ions, (ii) at least one complexing agent for the trivalent chromium ions, being different from the at least one corrosion-inhibiting agent, and (iii) at least one corrosion-inhibiting agent, which is (A) one or more than one substituted azole compound and/or salts thereof, together in a total concentration below 10 mg/L, based on the total volume of the passivation composition, and/or (B) one or more than one unsubstituted or substituted aliphatic organic acid with at least one mercapto-group and/or salts thereof, together in a total concentration in a range from 0.001 mg/L to 100 mg/L, based on the total volume of the passivation composition.

An object is to provide a trivalent chromium chemical conversion treatment liquid for a zinc or zinc alloy base capable of forming an environmentally-friendly chemical conversion coating with high corrosion resistance. The present invention provides a hexavalent chromium-free trivalent chromium chemical conversion treatment liquid for zinc or zinc alloy, the liquid comprising trivalent chromium ions, zirconium ions, nitrate ions, and chain colloidal silica, in which the pH of the treatment liquid is 2.5 to 5.0.

An object is to provide a trivalent chromium chemical conversion treatment liquid for a zinc or zinc alloy base capable of forming an environmentally-friendly chemical conversion coating with high corrosion resistance. The present invention provides a hexavalent chromium-free trivalent chromium chemical conversion treatment liquid for zinc or zinc alloy, the liquid comprising trivalent chromium ions, zirconium ions, nitrate ions, and chain colloidal silica, in which the pH of the treatment liquid is 2.5 to 5.0.

The chemical conversion treatment liquid according to the present invention, which is cobalt-free and is capable of forming a chemical conversion film having excellent corrosion resistance, contains a water-soluble trivalent chromium-containing substance, a water-soluble titanium-containing substance, and a water-soluble lactic acid-containing substance as essential components and may optionally contain a component at least a part of which is any of a water-soluble glycolic acid-containing substance and a water-soluble ineffective organic acid-containing substance. The water-soluble ineffective organic acid-containing substance is a water-soluble organic acid-containing substance based on an ineffective organic acid that is an organic acid other than lactic acid and other than glycolic acid. When the chemical conversion treatment liquid does not contain the water-soluble glycolic acid-containing substance and does not contain the water-soluble ineffective organic acid-containing substance, a titanium-equivalent molar concentration CTi of the water-soluble titanium-containing substance, a chromium-equivalent molar concentration CCr of the water-soluble trivalent chromium-containing substance, and a lactic acid-equivalent molar concentration CLc of the water-soluble lactic acid-containing substance satisfy the following Expressions (1) to (3): CTi/CCr≥0.5 ...(1); CLc/(CTi+CCr)≥0.40 ...(2); and CLc/CTi≤2.6 ...(3).

The chemical conversion treatment liquid according to the present invention, which is cobalt-free and is capable of forming a chemical conversion film having excellent corrosion resistance, contains a water-soluble trivalent chromium-containing substance, a water-soluble titanium-containing substance, and a water-soluble lactic acid-containing substance as essential components and may optionally contain a component at least a part of which is any of a water-soluble glycolic acid-containing substance and a water-soluble ineffective organic acid-containing substance. The water-soluble ineffective organic acid-containing substance is a water-soluble organic acid-containing substance based on an ineffective organic acid that is an organic acid other than lactic acid and other than glycolic acid. When the chemical conversion treatment liquid does not contain the water-soluble glycolic acid-containing substance and does not contain the water-soluble ineffective organic acid-containing substance, a titanium-equivalent molar concentration CTi of the water-soluble titanium-containing substance, a chromium-equivalent molar concentration CCr of the water-soluble trivalent chromium-containing substance, and a lactic acid-equivalent molar concentration CLc of the water-soluble lactic acid-containing substance satisfy the following Expressions (1) to (3): CTi/CCr≥0.5 ...(1); CLc/(CTi+CCr)≥0.40 ...(2); and CLc/CTi≤2.6 ...(3).

The invention relates to a method for producing a silane-modified silicate. In order to obtain optimal corrosion protection properties, a silane compound according to the invention is at least partially hydrolyzed and/or condensed in the presence of a silicate compound at a pH value greater than or equal to 8 and then a pH value less than or equal to 7 is set by adding acid. The invention further relates to an aqueous acidic passivation composition for metal substrate coated with the passivation composition.

A steel sheet coated with a zinc-based coating layer having a reaction layer on the surface of the steel sheet is manufactured by a method that includes bringing a steel sheet coated with a zinc-based coating layer into contact for 1.0 second or more with an alkaline aqueous solution containing one or more chelating agents selected from among sodium gluconate, sodium glucoheptonate, sodium citrate, tartaric acid, arabonic acid, galactonic acid, sorbit, mannite, glycerin, EDTA, and sodium tripolyphosphate in a total amount of 0.050 mass % or more and having a pH of 10.0 or more as a pre-treatment before a formation of the reaction layer, and forming the reaction layer being an oxide layer containing a crystal-structured substance expressed by Zn.sub.4(SO.sub.4).sub.1-X(CO.sub.3).sub.X(OH).sub.6.nH.sub.2O.