Alkaline zinc-iron plating bath

Abstract

This alkaline zinc-iron plating bath contains a zinc compound, an alkali metal hydroxide, an iron-containing metal salt, and a complexing agent, wherein the complexing agent is an aliphatic compound having five or more hydroxyl groups. Thus, by using an aliphatic compound having a chain structure having five or more hydroxyl groups as a complexing agent, for example, redissolution of a deposited coating film is suppressed by an inhibitor effect, and as a result, a thick coating film can be effectively formed.

Description

technical field [0001] The present invention relates to alkaline zinc-iron plating baths containing zinc compounds, alkali metal hydroxides, iron-containing metal salts and complexing agents. Background technique [0002] In alkaline zinc-based baths it is common practice to have low current efficiency, especially in alkaline zinc-iron baths, the current efficiency is very low. This is because in order to simultaneously dissolve zinc and iron in a high-alkali bath, it is necessary to use a complexing agent having a high complex stability constant, such as triethanolamine, which makes it difficult to cause electrolytic deposition. In addition, an example of an alkaline zinc-iron plating bath is described in the following patent document. [0003] prior art literature [0004] Patent Literature [0005] Patent Document 1: Japanese Patent Publication No. Sho 62-238387 SUMMARY OF THE INVENTION [0006] The problem to be solved by the invention [0007] As mentioned above,...

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Problems solved by technology

[0002] In alkaline zinc-type baths, generally low current efficiencies are customary, especially in alkaline zinc-iron baths where current efficiencies are very low

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