N,N-Dimethylaniline as corrosion inhibitor for zinc in sulphuric acid medium

Abstract

The inhibitive effect of N, N-Dimethylaniline (DMA) as corrosion inhibitor for zinc in 0.1, 0.3 and 0.5 M H₂SO₄ solutions has been investigated by using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results obtained reveal that inhibition efficiency (I.E.) increases with increase in concentration of inhibitors but decreases with increase in temperature. As inhibitor concentration increases corrosion rate decreases. The rate constant ‘k’ decreases while half-life ‘t_½’ increases with the increase in concentration of inhibitor. DMA showed maximum I. E. of 93.51 % at 60 mM in 0.5 M H₂SO₄ acid at 301 K. The inhibition effect is discussed in view of DMA molecules adsorbed on the metal surface and it obeys Langmuir adsorption isotherm. Polarization curve indicates that inhibitor act as mixed type for zinc corrosion in sulphuric acid solutions.