45030

Iron plating on copper [Spain] 

May 8, 2007

In my free time I make engravings(dry-points, etchings, etc.) and I electroplate the copper with iron to get a harder surface and be able to print more copies.
I have obtained the best results (brightness + hardness) with alcalyne-organic baths (pH =10...12): I have used for years the ferrocyanure bath from Boettger and now a sodium gluconate + Fe-sulfate bath (easier to prepare).
(Note1: pH high alone makes iron and nickel deposits very bright and hard, but in the case of iron, inorganic baths do not work with high pH as Fe hydroxide precipitates).
(Note2: I tried an inorganic, high pH, nickel bath and worked wonderfully but nickel is difficult to remove from copper without any dammage to the plate and for this reason is not much appreciated by the artists which often want to modify the plate).

But these organic baths do not take any iron from the anode, owing to the high pH, so they have to be replaced often, and are very expensive.
QUESTION: Is there a way to return to the bath the lost iron, without changing the properties of the bath? I am thinking of using iron hydroxide but I fear that it will be not be solved as the pH is so high.

Francesc Casanellas
Hobbyist - Aiguafreda (Barcelona), SPAIN