Showing papers by "Belkheir Hammouti published in 2004"

Corrosion inhibition of iron in hydrochloric acid solution by jojoba oil

Abstract: The influence of addition of the natural material, jojoba oil, on the corrosion of iron in molar hydrochloric acid had been studied using weight loss measurement and electrochemical polarisation methods. It was found that the corrosion rate was significantly reduced in the presence of jojoba. It was also found that the corrosion inhibition efficiency increased with the concentration of the jojoba oil to attain a 100 per cent inhibition at 0.515 g/l of jojoba oil, indicating that jojoba oil was an excellent corrosion inhibitor. The effect of temperature on the corrosion behaviour of iron indicated that the inhibition efficiency of jojoba oil decreased very slightly with the rise of temperature. It was found that the adsorption of jojoba oil on the iron, which followed the Frumkin isotherm, was the main cause to the corrosion inhibition.

A study of anti‐corrosive effects of Artemisia oil on steel

Abstract: The effects of natural Artemisia oil on the corrosion of steel in molar hydrochloric acid were studied by the measurements of weight loss, electrochemical and EIS polarisation. The results obtained revealed that Artemisia oil reduced the rate of corrosion. The corrosion inhibition efficiency increased with the increase of inhibitor concentration. Potentiodynamic polarisation studies clearly revealed that the presence of the natural Artemisia oil did not alter the mechanism of the hydrogen evolution reaction and acted essentially as a cathodic inhibitor. Good agreement between gravimetric and electrochemical polarisation results was noted. The effect of temperature on the corrosion behaviour of steel in 1M HCl, with and without the oil in the temperature range of 308‐353 K, indicated that inhibition efficiency increased with temperature. The adsorption of Artemisia oil on the steel is followed by Frumkin adsorption isotherm.

Characterisation of a new tripyrazole derivative as inhibitor for the steel corrosion in acid solution

Abstract: The inhibition of corrosion of steel in 1 M HCl solution by newly synthesised pyrazole derivatives has been studied by weight loss and polarisation techniques at 308°K. Its inhibitory power is compared to N,N′‐bis(3,5‐dimethylpyrazol‐1‐yl‐methyl)‐pentanolamine (Bipyr). The results obtained reveal that tripyrazole exhibits a good protection. Inhibition is found to increase with increase in inhibitor concentration. The inhibition behaviour of the compound has been explained on the basis of molecule size and charge density of adsorption active centres. The adsorption phenomenon obeys the Langmuir adsorption isotherm model.

Corrosion inhibition of mild steel in hydrochloric acid solutions by malonitrile compounds

Abstract: p-methoxy benzylidene malonitrile (MN1) and p-hydroxy benzylidene malonitrile (MN2) were synthesized and tested as inhibitors for the corrosion of mild steel in molar HCl. We have found that both of them inhibit the corrosion. The maximum inhibition efficiency reached 100% for MN1 at 10-4 M and for MN2 at 10-3 M. Current-voltage curves indicated that malonitriles act as mixed type inhibitors. Their adsorption on the steel surface obeys to the Langmuir isotherm model. The effect of temperature on the corrosion behaviour of steel indicated that the inhibition efficiency of the two inhibitors decreases slightly with the rise of temperature in the range 298-338 K. The apparent activation energies for steel dissolution are greater than in the absence of inhibitors, which is consistent with a chimisorption mechanism.