26 JJJ
26 JJJ
26 JJJ
Electrode Kinetics
Activation polarization.
and
Concentration polarization.
ACTIVATION POLARIZATION
ηa = ± β log (i/io)
Where:
ηa is overvoltage, β is a constant, and i is the
rate of oxidation or reduction in terms of
current density.
At all potentials more noble than the
reversible potential a net oxidation process
occurs.
Where:
iL is the limiting diffusion current density,
D is the diffusion coefficient of the reacting ions,
CB is the concentration of the reacting ions in the
bulk solution, and
x is the thickness of the diffusion layer.
This equation applies to almost all anodic dissolution reactions except for
metals which demonstrate active-passive behavior.
Generally: