The corrosion protection of stainless steel 304 (SS 304) in 2M HCl solutions using Clindamycin antibiotic was investigated by weight loss (WL), electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) tests. Electrochemical results showed that this compound is an efficient inhibitor for SS304 and the efficiency reached 93 % at 300 ppm. The inhibition efficiency (IE) increases with the drug concentration and decreases with rising temperature. Data from electrochemical measurements suggested that the drug functioned by adsorption of the molecule on the metal/corroding interface, inhibiting both the cathodic and anodic half-reactions of the corrosion process. The adsorption of this drug on SS304 surface follows Langmuir adsorption isotherm. The thermodynamic functions of activation and adsorption processes were calculated and discussed. The surface morphology of the SS304 specimens was evaluated using atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR).

In 1 M HCl pickling media, the paprika extract was used as an ecofriendly anti-corrosive material for carbon steel. Many strategies were utilized to estimate the mitigation efficacy such as potentiodynamic polarization (PP), frequency modulation (EFM), electrochemical impedance spectroscopy (EIS), and mass loss. Surface analyses were accomplished by scanning microscopy (SEM) and dispersion X-ray (EDX) techniques. The mitigation efficacy ameliorates with the concentration of extract and temperature. The inhibition is ascribed to the building of a protective coating at the surface of carbon steel that reduces its dissolution. The adsorption of Paprika extract on steel metal satisfied Langmuir , s model. The adsorption belongs to the physical and chemical types. The adsorption of the extract affected both anodic and cathodic reactions. Tafel curves demonstrated that the Paprika is a mixed inhibitor. The Nyquist curves confirmed that Paprika extract prohibits the disintegration of steel in acid media without changing the dissolution reaction mechanism. The adsorption of the Paprika extract on the carbon steel metal was confirmed by ATR -FTIR analysis and SEM examination. Using 300 ppm of Paprika extract, a maximum inhibitory efficacy of 95% was observed at 313 K.

The corrosion behavior of carbon steel  in 1 M HCl solution in the absence and presence of 4-(2-Cyano-7- hydroxy-4-methylene-hepta-2,5-dienoylamino)-benzoic acid (a), 4-[2-Cyano-3-(4-methoxy -phenyl)-acryloylamino]-benzoicacid.(b), 4-(2-Cyano-3-phenyl acryloylamino)-benzoic acid (c) ,4-[3-(4-Chloro-phenyl)-2-cyano-acryloylamino]-benzoic acid(d), was investigated using weight loss , potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The inhibitive action of the investigated compounds was discussed in terms of blocking the electrode surface by adsorption of the molecules through the active centers contained in their structures. The adsorption of these derivatives on carbon steel surface is consistent with Freundlich adsorption isotherm. The effect of temperature on the rate of corrosion in the absence and presence of these compounds were also studied. Physical adsorption mechanism is proposed from the calculated thermodynamic parameters for all investigated compounds.

No abstract

The inhibitive action of some phenylthiazole derivatives namely: 2-acetylamino-5-p-bromophenylazo-4-phenylthiazole (BPT), 2-acetylamino-5-p-methylphenylazo-4-phenylthiazole (MPT), 2-acetylamino-5-p-methoxyphenylazo-4-phenylthiazole (XPT) and 2-acetylamino-5-p-nitrophenylazo-4-phenylthiazole (NPT), on zinc corrosion in 0.2 M HCl  has been studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS)and electrochemical frequency modulation (EFM) measurements. The results showed that the dissolution rate of zinc decreases with increasing the phenylthiazole derivatives concentration and decreases with raising temperature. Polarization curves indicated that the studied inhibitors act as mixed-type inhibitors. The adsorption of the investigated compounds follows Langmuir adsorption isotherm model. The thermodynamic parameters of adsorption and corrosion processes were determined and discussed.