Kawasaki Steel Corporation

Katsuhei Kikuchi

Nobuo Totsuka

Takao Kurisu

Yoshihiro Naruse

Sachiko Suzuki

Masaki Mabuchi

Keizo Okuno

A blackened steel strip having improved blackness is produced in an efficient manner by anodizing a zinc alloy-plated steel strip in a solution containing 5 to 100 g/l of ClO.sub.3.sup.- and 10 to 300 g/l of SO.sub.4.sup.2- at pH 0.5 to 2.5 at a temperature of 30.degree. to 75.degree. C. and with a quantity of electricity of 10 to 300 C/dm.sup.2, and forming an acrylic resin chromate layer on the anodized steel strip to a thickness of 0.3 to 2.5 .mu.m. The solution may contain 5 to 100 g/l in total of at least one co-additive selected from Cl.sup.-, NO.sub.3.sup.-, H.sub.2 O.sub.2, Ni.sup.2+, Co.sup.2+, Fe.sup.2+, and Mn.sup.2+. The acrylic resin chromate layer contains 2 to 10 parts by weight of in the form of a chromate Cr per 100 parts by weight of acrylic resin.

Efficient preparation of blackened steel strip

A surface-treated metal sheet which excels in workability, electrical conductivity and corrosion resistance has a metal sheet which has been plated as required, a chromate layer as a first layer formed on at least one side of the metal sheet, with a deposition amount of about 5 to 200 mg/m.sup.2 as calculated on the basis of Cr, and a second layer formed on the first layer from organic lubricant particles, with a deposition amount of from about 5 to 1000 mg/m.sup.2, such that the area coated by the organic lubricant particles to the entire area of the metal sheet surface is below about 50%. The second layer is preferably applied with a roll coater, a spin coater or a dip coater, a dispersion liquid or an emulsion containing about 0.1 to 40 wt. % of the organic lubricant particles so as to provide a wet film thickness of about 0.2 to 10 .mu.m.

Surface-treated metal sheet which excels in workability, electrical

An electrolytic process for forming a pattern on a metallic object makes use of a screen of electrically insulating material having a perforated pattern corresponding to the pattern to be formed on the metallic object. A paste containing an electrolyte is applied to the surface of the metallic object through the pattern of the screen. Electric current is supplied between the metallic object and an electrode placed in contact with the electrolyte-containing paste so that electrolysis takes place through the pattern of the screen on the surface of the metallic object. Disclosed also is an electrolytic apparatus suitable for use in carrying out the method.

Electrolytic process and apparatus for forming pattern on surface of

A black colored steel strip having improved degree of blackness and uniform appearance is prepared by subjecting a Zn-Ni alloy plated steel substrate to anodic electrolysis or alternating current electrolysis in an electrolyte solution containing at least one member selected from the group consisting of hydroxide, sulfate, and chloride of sodium, potassium, or nickel; nitrate ion; and at least one member selected from an inhibitor and a complexing agent.

Growing community of inventors

Chiba, Japan

Katsuhei Kikuchi