Question

Which following expression is used to find the corrosion rate from current density of a corroding specimen?

(a) W/At = [(I × am) / (n × F)]

(b) W/At = [(I × am) / (n × d × F)]

(c) W/At = [534 × (I × am) / (n × F)]

(d) W/At = [(I × am) / (n × F)] and W/At = [(I × am) / (d × n × F)]

This question was posed to me by my college director while I was bunking the class.

This intriguing question comes from Corrosion Rate Expression topic in portion Corrosion Principles of Corrosion Engineering

Answer 1

Right option is (d) W/At = [(I × am) / (n × F)] and W/At = [(I × am) / (d × n × F)]

The explanation: W/At denotes the corrosion rate, I= current density, am=molecular weight, n=number of electrons transferred, F=faraday constant (96500), d=density of a specimen. [(I*am) / (n*F)] is used to calculate the MDD whereas the [(I*am) / (n*d*F)] is used to calculate the MPY.