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Electrochemical measurements were used to characterize the inhibiting effectiveness of Curcuma and saffron, considered as green inhibitors in a corrosive environment 3% NaCl on A106 Gr B carbon steel.

This study/paper aims to polarization and potentiodynamic impedance spectroscopy techniques were performed on A106 Gr B carbon steel in the 3% NaCl environment only and containing various concentrations of Curcuma and Saffron (0.005, 0.01, 0.02, 0.04, g/L) after 30 min of immersion; these measures were taken at a temperature of (298 ± 1)K. A voltlab PGZ 301 assembled by A 106 Gr B carbon steel working electrode, a platinum counter electrode (CE) and a saturated calomel electrode as the reference electrode were used in the experiment. In this research, potentiodynamic polarization and electrochemical impedance spectroscopy were used.

The inhibition efficiencies increased with increase in the concentrations of the inhibitor but decreased with rise in temperature. The obtained results show an optimal efficiency with 0.04 g/L which are ordered of 78 and 96 per cent successively for the two inhibitors. Curcuma and saffron acts as a mixed type inhibitor. Adsorption of the inhibitor molecules corresponds to Langmuir adsorption isotherm. Mechanism of inhibition was also investigated by calculating the thermodynamic and activation parameters like (ΔG), (E_a), (ΔH_a) and (ΔS_a). The inhibitor molecules followed physical adsorption on the surface of carbon steel.

The present trend in research on environmental friendly corrosion inhibitors is concentrating on products of natural origin due principally to non-toxicity and eco-friendliness. Among these natural products are curcuma and saffron.

The purpose of this study was to investigate the inhibitive action of some green leaves on Monel 400 alloy in acidic media.

Green leaves of Mespilus japonica, Ricinus communis L and Vitis vinifera were immersed in methanol solutions, separately, and filtrated after 48 h of immersion; the obtained filtrates were examined as corrosion inhibitors of Monel 400 alloy in hydrochloric acid solution (1.0M HCl). The performance of these inhibitors was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization. The effect of temperature on corrosion behavior of Monel 400 was also studied.

The results obtained showed that all tested inhibitors performed as good corrosion inhibitors. The inhibition process is attributed to the adsorption of the inhibitors on Monel surface. The adsorption behavior was found to follow Langmiur isotherm. The inhibition efficiencies of extracts increased with increasing the concentration of each inhibitor and deceased with increasing the temperature.

Practical implication These inhibitors could have application in industries where hydrochloric solutions were used to remove the surface impurities of Monel 400.

This paper helps to find new corrosion inhibitors that are safe and eco-friendly.

Corrosion and corrosion inhibition of alloyed zinc electrode were investigated in neutral chloride solution using electrochemical techniques. The purpose of this study is to study the corrosion inhibition of acetanilide and para hydroxy acetanilide as organics inhibitors for corrosion control of alloyed zinc electrode in NaCl 3 per cent solution.

A volt lab PGZ 301, assembled using alloyed zinc working electrode, a platinum counter electrode and a saturated calomel electrode as the reference electrode, was used in the experiment. This research was conducted using potentiodynamic polarization and electrochemical impedance spectroscopy techniques.

Acetanilide, para hydroxy acetanilide and their mixture provided inhibitions efficiencies of 88 per cent at 40 ppm, 87 per cent with 80 ppm and 99.86 per cent with (40 ppm AC + 80 ppm PHA), respectively. The study also discusses the corrosion inhibition mechanism of the protective layers. The adsorption of acetanilide and para hydroxy acetanilide on metal surface obeyed Langmuir’s adsorption isotherm. Polarization measurements showed that the acetanilide and the para hydroxy acetanilide, and their mixture acted as cathodic inhibitors in NaCl solution, and the inhibitor molecules followed physical adsorption on the surface of alloyed zinc.

The other new inhibitors which are very efficient inhibitors and to be applied in the field of prevention and control against corrosion.