Effect of solution impurities on morphology and composition of copper electrodeposits obtained in membrane based cell

Chemical and physical characterisation of copper electrodeposits obtained on mesh and plate cathodes in a lab scale reactive electrodialysis cell and cells of conventional design have been carried out. The effect of Fe, Mn, Cl and guar in the electrolyte on electrodeposit composition and morphology were determined by means of metallographies, scanning electron microscopy, energy dispersive spectrometer, atomic force microscopy and inductively coupled plasma mass spectrometry. Metallographies revealed that electrolytes with Cl, Fe and Fe-Cl-Mn generated thick columnar deposits. Impurity free and Mn containing solutions produced thin columnar electrodeposits. The presence of all the impurities plus the organic additive resulted in small grained equiaxial electrodeposits. Atomic force microscopy revealed that the latter deposits, and those where Mn was present in solution, exhibited the smoother surfaces (100-200 nm mean surface rugosity) whereas other deposits showed higher degrees of roughness (over 400 nm mean surface rugosity). Impurities and additive were present in small concentrations (<1 mg dm(-3)) in the produced electrodeposits.