Inhibition of Corrosion of Aluminium in Potassium Hydroxide Solution by Pyridine Derivatives

The influence of 3-methylpyridine and 3-nitropyridine on the corrosion rate of aluminium in 1 mol L−1 potassium hydroxide solution was investigated using weight loss method. It was observed that both investigated derivatives behave as inhibitors. It was found that the inhibition efficiency increases with increasing inhibitor concentration. The inhibition mechanism is discussed on the basis of adsorption of inhibitor molecules on the metal surface. The inhibitors were adsorbed on the surface according to the Frumkin adsorption isotherm. The effect of temperature on the corrosion inhibition of Al was studied and thermodynamic functions for the dissolution and adsorption processes in the absence and in the presence of the inhibitors were computed and discussed.