We present an experimental and theoretical study of front interaction durin
g the growth of patterns in thin-layer electrochemical deposition. Simultan
eous schlieren and particle image velocimetry techniques are used to follow
front development of concentration fields and convection rolls in gravitoc
onvection prevailing Rows. A theoretical model describing full front nonlin
ear interaction taking into account diffusive, migratory and convective mot
ion of ions in a viscous fluid subject to an electric field is presented. T
he equations are written in terms of a set of dimensionless numbers showing
the significance of the gravity Grashof number in a gravitoconvection prev
ailing regime. Our experiments reveal that concentration and gravity driven
convection fronts which develop near the electrodes coincide and that the
two evolve together. Prior to the appearance of rough growth, cathodic and
anodic concentration and convective fronts are parallel to the electrodes.
After branching develops, the cathodic fronts become slaved to the deposit
front, all three growing linearly in time. Our model predicts that, in the
parallel flow regime, the convective and concentration fronts coincide, bot
h scaling first as t(4/5) and then slowing down to t(1/2), as it is observe
d in our experiments. After branching develops, this behavior applies only
to the anodic front.