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:
Nov. 16, 2004
Filed:
Aug. 21, 2003
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention provides a surface treated steel sheet for electronic components which does not include lead, which is a hazardous substance with environmental impact, and, in particular, satisfies the solder wettability after retort treatment, a rust-proof property and a whisker-proof property simultaneously. More specifically, the present invention is a surface treated steel sheet with less environmental impact for electronic components excellent in solder wettability, a rust-proof property and a whisker-proof property and having an Sn—Zn alloy layer which is formed by plating Sn and Zn on a steel sheet or a Ni plated steel sheet and then applying thermal diffusion treatment, or by plating Sn—Zn alloy on a steel sheet or a Ni plated steel sheet, characterized in that the amount of said Sn—Zn alloy layer is not less than 3 g/m , the Zn/Sn ratio (in weight ratio) is 0.01 to 10, more preferably 0.01 to 0.1, and an inorganic film mainly composed of magnesium phosphate is formed in the amount of 1 to 100 mg/m in terms of the amount of P+Mg on said Sn—Zn alloy layer.