The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 16, 1991
Filed:
Jun. 21, 1990
Katsushi Saitou, Chiba, JP;
Yuujirou Miyauchi, Chiba, JP;
Kazumi Shibata, Chiba, JP;
Kouichi Wada, Chiba, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
A surface-blackened steel sheet is produced by electrolyzing a steel sheet at a cathode in an acidic aqueous solution containing Zn.sup.2+, at least one of Fe.sup.2+, Co.sup.2+ and Ni.sup.2+, a film-improving ion consisting of at least one member selected from the group consisting of Cr.sup.3+, Fe.sup.2+, Pb.sup.2+, In.sup.2+, Ag.sup.2+, Sn.sup.2+, Ti.sup.2+, Al.sup.3+, Cu.sup.2+, Mo.sup.6+, V.sup.3+, V.sup.6+, Mn.sup.2+, Mn.sup.4+, Mn.sup.6+, Bi.sup.2+, sulfite ion, thiosulfate ion, thiocyanate ion, sulfamate ion and sulfonate ion, an oxidizing ion and an organic hydroxy-compound as main components, thereby forming a black film on the steel sheet, followed by water washing, a chromate treatment, if required, and coating with a guard coat.