Surface treatment of steel products electroplated with iron-zinc alloy

Abstract

Abstract PURPOSE:To enhance the rust preventiveness of steel products after coating by phosphating the steel products each having a plated layer of a Zn alloy as an under layer and an upper layer of an Fe-Zn alloy to dissolve the upper layers of the products and to convert the surfaces into phosphophyllite-base phosphate coats. CONSTITUTION:Steel products each plated with a Zn or Zn alloy layer as an under layer and an Fe-Zn alloy layer consisting of >=60wt% Fe and the balance Zn as an upper layer are manufactured. The steel products are treated with a phosphating soln. contg. phosphate ion, Zn ion, alkali metallic ion, an accelerator and heavy metallic ion. By the treatment the upper layers of the steel products are dissolved and the surface layers are converted into phosphophyllite-base phosphate coats. When the amount of phosphophyllite in the surface layers is >=50wt%, satisfactory properties are obtd.

Inventors

• 👤 Masaaki Ohashi
• 👤 大橋　正昭
• 👤 Yasuhiko Tsuzuki
• 👤 都築　安彦
• 👤 Satoshi Hanai
• 👤 花井　諭
• 👤 Kametaro Ito
• 👤 伊藤　亀太郎

Bibliographic Details