The conditions I used for the electrodeposition are mentioned below.
Electrolytic solution:
30gms of CuSO4
5ml of H2SO4
150ml of DI water
Electrodeposition parameters:
Current density - 0.25mA/mm2
The voltage at the beginning was 0.4V and started increasing gradually. After three and a half hours, there was a change in resistance with a yellow color formation on the anode and voltage started fluctuating. It suddenly rises to 16V and then drops to 8V.
May I know what's wrong with my approach? And can you suggest me the best approach to deposit 150-175 microns of copper on copper?
Hello Priyadharshini Aravind,
Thanks for your reply. Both the electrodes are 99.8% copper
Hi Christian Punckt,
I am using magnetic stirrer @ 200rpm in a 250ml beaker. Anode and cathode have same area i.e 800mm2 (40mm*20mm). By complex formation what are you referring to?
+1 to Christian's answer.
The voltage behavior is telling you exactly why constant current depositions are problematic (also why 2-electrode experiments are problematic). Nominally, if you have enough mass transport from convection/flow/stirring, then you can overcome the problem of depletion. However, even if you do, and all of your cathodic current is from electrodeposition of your desired species, you still have the issue of what is giving [anodic] current at the counter electrode. Most people don't care and so the fixes are to use (ideally much) larger areas and to use more noble materials as counters (Pt, graphite) that are less likely to end up passivating, filming or contaminating the electrolyte.
...Looking again at your setup, it could also be as simple as bulk depletion not supporting your current for that length of time, so there may be cathode and anode side reactions.
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