of this layer is
called the effective (or equivalent) thickness of the diffusion layer. Its definition is apparent from the
figure. It is the thickness which the diffusion layer would have if
the concentration profile were a straight line coinciding with the
tangent to the true concentration profile at the interface, and that straight line were extended up
to the point where the bulk concentration is reached.
has a formal
significance only. It is simply another way of writing the
mass transfer coefficient
defined in terms of a resistivity instead of a
conductivity.
Source:
PAC, 1981, 53, 1827
(Nomenclature for transport phenomena in electrolytic systems)
on page 1837