Refer this link:http://link.springer.com/chapter/10.1007/978-90-481-3477-9_5#page-1

Refer this link:

Thanks Dr. Babu !!

corrosion is stipulated in weight loss (mass dissolved)  unit area/per time unit.

or depth lost (dissolved) per time unit.

in mass / depth it is essentially the density.

so why not apply simple arithmatics to help yourself

In order to help You understand from where 1.116x10^7 comes from, I need to know what metal is concerned in the paper. The Faraday law uses the number of electrons produced by the oxydation of the metal, could be 1 or 2 etc...and the atomic mass of the element....need to know the element.

Calculation of Corrosion Rate from the Corrosion Current

According to Faraday’s Law:

                                W = QM/nF                (equ.1)

Where

Q = coulombs

n = number of electrons involved in the electrochemical

reaction

F = Faraday constant, 96,487 coulombs

W = weight of the electroactive species, gram

M = molecular weight

Since equivalent weight  EW= M/n

and since Q = it   from Faraday’s Law

where

i is the current, amp

t is the exposure time, sec.

so, W/t is the corrosion rate (C.R.) in grams/second.

It is convenient and traditional to express corrosion rate as milli-inches per year (mpy). These units provide an indication of penetration.

Dividing equation (1) by the electrode area and the density of the metal sample gives:

C.R. (cm/sec) = i (E.W.)/dFA

Convert seconds to years and centimeters to milli-inches.

Convert the Faraday (amp-sec/eq) to microamps.

Express the terms i/A as current density. Combining all

the constants gives:

Corrosion Rate (mpy) = [ 0.13 ICORR (E.W.)]/d (Eq. 2)

ICORR = corrosion current density, μA/cm2

E.W. = equivalent weight of corroding species, g

d = density of corroding species, g/cm3

Equation (2) is used to calculate the corrosion rate

directly from ICORR.

Conversion of (Eq.2) from mpy to micrometer per year (um per y), Equ.2 becomes;

 Corrosion Rate (um py) = [3.302 ICORR(EW)]/d

Then try to mathematically manipulate the above equation(Equ.2) to:

corrosion Rate = (1.116x10^7 x WL)/(AxT)

If you divide the weight corrosion rate in the unit [g/(cm2 h)] by the density of the metal, you will receive the linear corrosion rate in the unit [mm/year]. Remember that you have to convert hours to the year: 8760 hours per year.