Inhibition of corrosion of aluminium in hydrochloric acid by cobalt tetrasulphophthalocyanine

Inhibition of corrosion of aluminium in 2M HCl by cobalt tetrasulphophthalocyanine (CoTSP) has been investigated by gasometry, thermometry, weight loss and polarization techniques. The test Al strips were Indal 2S, of composition Al-0.5Fe-0.3Si-0.02Ga-0.01Ti. Inhibitive property is exhibited in concentrations as low as 10 exp -7 M but reaches its maximum in concentrations exceeding 2x10 exp -4 M. The activation energy of the dissolution process is found to increase with increasing inhibitor concentration and Arrhenius activation energies show that the inhibition process is activation controlled.