Abstract
In order to better understand alloy electrodeposition processes, it is essential to isolate the various phenomena involved in film formation. One important aspect in this context is the natural convection occurring in electrochemical cells, observed in the presence of gravity and due to the change in electrolyte density upon electrode reactions. These convection patterns can be minimized by the use of horizontal electrodes, with the cathode on top and facing down. Using this geometry and comparing with a number of other cell configurations, we have observed that the suppression of natural convection leads to more uniform nucleation and tighter composition distribution in Cu-Zn-Sn ternary alloy films. Experiments in a flat cell on alloy dendrite growth show that the most stable growth is again in the top cathode configuration; alloying Ag or Ni with Cu leads to more dense dendrites, increase in tip splitting occurrence and in some cases to the destabilization of dendrite formation, leading to dense and compact films.
