5. Ways of expressing the effectiveness of a corrosion inhibitor

There are several ways of expressing the efficacy of an inhibitor or inhibitory formulation. The most common expressions are :

• the inhibition rate, most often used : $\text{τ}\text{\%}=\frac{u_0-u}{u_0}\times 100$

  where u ₀ is the corrosion measurement (mass loss, corrosion intensity, etc.) in the absence of inhibitor, and u the measurement in the presence of inhibitor ;

• inhibition coefficient : $\gamma =\frac{u_0}{u}$

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