When mild steel is passivated in inhibitive solutions, the thickening of the (oxide)film on the surface of the steel is a function of the logarithm of time, as it is in dry air, and the constants of this ‘logarithmic’ growth are of the same order ofmagnitude in all environments. This suggests that a similar mechanism of growth is operating in the various conditions.
Constants for growth in different solutions nevertheless show minor variations, and values for growth in aerated solution are always slightly greater than that for growth in dry air.
