Electroplated Coating of Zinc Alloy with Excellent Corrosion Resistance and Plated Metal Material Having Same

Abstract

Objects of the present invention is to provide a zinc-based alloy electroplated film having a high corrosion resistance comparable to Zn—Cr alloy plating without containing chromium which gives a heavy environmental load, and a plated metal material using the same. The present invention relates to a zinc-based alloy electroplated film excellent in corrosion resistance containing (A) 30 to 96% by weight of zinc, (B) 2 to 20% by weight of an iron-group metal, and (C) 2 to 50% by weight of tungsten.

Description

TECHNICAL FIELD[0001]The present invention relates to a zinc-based alloy electroplated film excellent in corrosion resistance and a plated metal material using the same, which can be utilized in a wide range of fields such as automobiles, home electric appliances, and building materials.BACKGROUND ART [0002]In response to the request for high corrosion resistance on metal materials to be used in automobiles, home electric appliances, building materials, and the like, there has been increasingly utilized zinc-based alloy metal materials where iron-based materials are coated with zinc or a zinc-based alloy plated film. Various kinds of methods for coating iron-based materials with zinc are present. As the plating methods, hot dip galvanization where a plated film is formed by dipping a base metal in molten zinc or zinc alloy and electrogalvanization where a plated film is formed by precipitating metallic zinc dissolved in an aqueous solution through electrolysis have been known. Furth...

AI Technical Summary

Benefits of technology

[0008]An object of the invention is to provide a zinc-based alloy electroplated film having a high corrosion resistance comparable to Zn—Cr alloy plating without containing chromium which gives a heavy environmental load, and a plated metal material using the same.

[0009]As a result of extensive studies for solving the above-described problems, the present inventors have found that corrosion resistance can be remarkably improved by using a plated film containing zinc as a base material and specific amounts of an iron-group metal and tungsten, and have accomplished the invention.

Problems solved by technology

However, with regard to the metal materials used in automobiles, home electric appliances, building materials, and the like and exposed under severe conditions, even when these plated metal materials are utilized, a sufficient corrosion resistance cannot be obtained in some cases and thus further improvement of corrosion resistance has been required.

As mentioned above, the Zn—Cr alloy plated film is practically excellent but it contains a problem of hexavalent chromium mist generated at plating and hence environmental problems of disturbing plating worker's health and inducing air pollution have been closed up.