Question

What is the formula to determine the slope of linear polarization curve?

(a) ΔE/Δi =[2.3*icorr*(βa+βb)]/[βa*βb]

(b) ΔE/Δi=[βa+βb]/[2.3*icorr*(βa*βb)]

(c) ΔE/Δi=[βa*βb]/[2.3*icorr*(βa+βb)]

(d) ΔE/Δi=[2.3*icorr*(βa*βb)]/[βa+βb]

I had been asked this question in an interview for internship.

The above asked question is from Modern Theory Applications in portion Modern Theory Applications of Corrosion Engineering

Answer 1

The correct choice is (c) ΔE/Δi=[βa*βb]/[2.3*icorr*(βa+βb)]

To elaborate: The slope of linear polarization curve is determined by using ΔE/Δi=[βa*βb]/[2.3*icorr*(βa+βb)] where βa , βb are Tafel slopes of anodic and cathodic reactions and icorr is the current density at the intersection point of anodic and cathodic reaction.