Surface treated steel sheet with less environmental impact for electronic components, excellent in solder wettability, a rust-proof property and a whisker-proof property

   
   

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.sup.2, 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.sup.2 in terms of the amount of P+Mg on said Sn--Zn alloy layer.

 
Web www.patentalert.com

< Method for manufacturing a steel sheet

< System for producing steel

> Ferritic stainless steel which can be used for ferromagnetic parts

> Quantitative measuring method and apparatus of metal phase using x-ray diffraction method, and method for making plated steel sheet using them

~ 00145