I want to sequentially deposit uniform layers of Cu, Ni, Fe and Zn, respectively on a gold layer. Is such sequential deposition possible galvanostatically?
In our experience a copper film on iron is very fragile, but nickel is robust on iron and copper.
For nickel coatings we use
NiSO_4*-6H_2O (0.95 mol/L)
NiCl_2*6H_2O (0.19 mol/L)
H_3BO_3 (0.65 mol/L)
with 100 mA/cm^2 (Y. Matsubara und H. Hamada, J. of ASTM Int. 3, 1-13, (2006).)
And for copper coatings we use
200mL H2O
6mL H2SO4
13mL Ethanol
25g CuSO4*5H2O
With 0.1 mA/cm^2
Thanks Martin. Could you also comment if the following order of deposition will work if we disregard iron? i.e. a film of Cu, then Ni, and finally Zn?
I have never used Zn, but Ni and Cu can be coated on each other with good adhesion.
As galvanic chemist I can say by experience yes.
Cu on gold is possible (important a good preparation of gold surface)
Nickel on copper is possible (i do, important nickel agitation and temperature 50°C)
Iron on nickel, possible but is important that nickel is not passivated or you may face lack of adhesion. To avoid this is important Nickel never become dry, so after nickel plating you have to rinse and plate iron in few minutes; (you may leave nickel plated substrate in the rinse for minutes before iron plating). Iron plating has to be done with hot solutions (60-70°C) to have a good layer
Zinc on iron is possible (is available in commerce iron protected by zinc).
Feel free to connect me for details on the solutions and the parameters.
My best
Cu, Ni, Fe and Zn, respectively on a gold layer. Is such sequential deposition possible galvanostatically?
It is possible to do that. You can check the publication of Oskar Modin et al. as a good reference: http://publications.lib.chalmers.se/records/fulltext/163014/local_163014.pdf
However, you should be aware that at a certain amount of current, the selectivity is not the same than what can be achieved by controlling the potential. Besides, the recovery process will be thermodynamically feasible or not depending on the concentrations you use of each metal. You should look at the mixed thermodynamic equilibrium to have more clarity of the limits, and such should be regarded also in perpective to gold.
Success will also depend on what is available in the electrolyte, as introducing other ions can shift the equilibria, other reactions may be then involved.
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