Studies on the Chemistry of Platemaking

On the amounts of dissolved Cu in various etching solution prepared from ferric chloride

Abstract

The purpose of this work is to find any other factors than Fe²⁺-Fe³⁺ concentration ratio which affect to the amounts of dissolved Cu²⁺.
Etching solutions were prepared by using FeCl₃ or Fe₂(SO₄)₃⋅(NH₄)₂SO₄ as ferric salt, FeCl₂ or FeSO₄ as ferrous salt and H₂O or HCl or H₂SO₄ as solvent.
By these etching solutions, Cu-plate was etched for 30 minutes, and then amounts of Cu²⁺ dissolved and redox potential were investigated.
The results were as fellows:
(1) It was clarified that the concentration of Fe³⁺ was important in etching and the most effective concentration seemed to be about 2Mol.
(2) Amount of dissolved Cu²⁺ was affected by the sorts of anion and ligands of Fe3⁺-compounds which were produced from solvent and Fe³⁺-salt.
From these results it was concluded that the shape and size of Fe³⁺-compounds in solutions were important in etching.