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This paper aims to evaluate the inhibitive action of different concentrations of Sesbania grandiflora leaf extract on the mild steel corrosion in an aggressive HCl medium under different experimental conditions.

Weight loss investigation, open-circuit voltage analysis, Tafel polarisation, AC impedance analysis, etc. were used for the evaluation of inhibition efficiency. The influence of immersion period on inhibition efficiency was evaluated. The mechanism of action of the inhibitor is also discussed. Infrared (IR) spectroscopy and energy-dispersive X-ray spectroscopy analysis were used to characterise the passive film.

The results suggested that 10,000 ppm solution has maximum inhibition efficiency of 98.01 per cent at room temperature, while 1,000 ppm solution also exhibited a better efficiency of about 96.16 per cent. Efficiency of inhibitor solution was found to increase with an increase in its concentration. Polarisation study proposed the solution as an anodic inhibitor. Impedance study confirmed the formation of a protective layer over the surface of the specimen, and the constituents of the film were identified using IR spectroscopy. Stability of the film adsorbed on the steel was cleared from the steady open-circuit potential value. Study on action of the inhibitor under accelerated conditions revealed the fact that the efficiency of extract in preventing corrosion is good under stimulated conditions also.

The action of inhibitor sustains for a sufficient time period and could sustain under stimulated conditions. Hence, its application is practically possible in industries. The proposed inhibitor is widely available and is environmentally safe.

HCl is an industrially important chemical used for acid cleaning, acid pickling, etc. HCl was used as an aggressive corrosion environment. As the chances for mild steel to be in contact with HCl were very high, it was important to develop an efficient, economical and eco-friendly inhibitor for corrosion.

The purpose of this paper is to adopt both the fragments of imidazole and thiosemicarbazide as reaction centers, to synthesize a water-soluble corrosion inhibitor named as thiosemicarbazide-imidazole derivative (TH-IM).

This paper presents potentiodynamic polarization tests, electrochemical impedance spectroscopy tests and morphology study of metal surface by scanning electron microscope and thermodynamic study.

In the aggressive condition of CO₂ saturated Wt. NaCl solution at 333 K for 72 h with 400 ppm inhibitor dosage, the efficiency of inhibition increases approximately 98 per cent through the method of weight loss.

This paper finds a new corrosion inhibitor about TH-IM which has a good solubility in water.

To evaluate the corrosion inhibition potential of Datura metel in acid medium on mild steel (MS) with a view to develop green corrosion inhibitors.

Acid extract of the D. metel was studied for its corrosion inhibitive effect by electrochemical and weight loss methods. Using weight loss measurement data, an attempt has been made to probe the mechanism of inhibitive action by fitting adsorption isotherms.

D. metel has been found to show significant corrosion inhibitive effect in acid medium on MS. Inhibition is through adsorption of the phytoconstituents on MS following Tempkin and Langmuir adsorption isotherms. The results of A.C. impedance and polarisation studies correlate well with the weight loss studies.

The plant has been investigated for the first time for its corrosion inhibitive effect. The effect has been studied by proven methods. This green inhibitor can find use in the inhibition of corrosion in industries where MS is used as a material of choice for the fabrication of machinery.

This paper aims to evaluate the inhibition efficiency of thiadiazole derivatives, such as 2,5-dimercapto-1,3,4-thiadiazole (DMTD), 5-methly-2-mercapto-1,3,4-thiadiazole (MMTD) and 2,5-dithiododecyl-1,3,4-thiadiazole (DDTD), in 50 mg/L hydrogen sulfide for silver strip.

Evaluation was carried out by corrosion-inhibiting test, electrochemical measurement and surface analysis techniques. 3D surface profiler, atom force microscopy, scanning electron microscopy and energy-dispersive X-ray analysis were applied and finally confirmed the existence of the adsorbed film.

The electrochemical measurement showed that the inhibition efficiency increases with increasing inhibitor concentration in 50 mg/L hydrogen sulfide solution, while the corrosion rate and the corrosion current decrease. Weight-gained measurements also indicated that inhibitor decreases the corrosion rate in the studied solution. The adsorption of DMTD and MMTD on the silver surface obeys Temkin’s adsorption isotherm, but the adsorption of DDTD follows Langmuir’s adsorption isotherm. That means that the inhibition mechanism is different between DMTD, MMTD and DDTD. The ΔG0_ad values of DMTD, MMTD and DDTD were −37.47, −37.29 and −38.69 kJ/mol, respectively. It showed that there was an adsorption bond between silver surface and inhibitor, and the adsorption belongs to chemical adsorption.

The inhibitors have an excellent inhibition efficiency, and the best inhibition efficiency is 91.76 per cent. Inhibitors can effectively inhibit metal corrosion in the oil and gas.

Anodic protection (A.P.) for corrosion control is based on the principle of protecting a metal or alloy from corrosion by raising the electrochemical potential of its surface to a value at which a protective oxide film (passive film) is formed and maintained. The principles of design of anodic protection systems are not very well developed. This paper discusses several important basic design concepts and describes several equations which can be used for the design and optimization of anodic protection systems for corrosion control.

The Special Metal Products Business Area of Degussa AG, Frankfurt am Main, presented an overview of its range of dispersion‐hardened platinum materials. These materials, which remain resistant to corrosion by aggressive media such as gases and salt or glass melts even at high temperatures and which are capable of withstanding high mechanical loads, are attracting considerable interest. The Degussa range now consists of the fine‐grain stabilised types FKS 16 Pt, FKS 40 Pt, FKS 16 PtRh and FKS 16 PtAu.

This paper aims to study the effect of Hg²⁺ on the corrosion behavior of Al–2%Zn coatings on AA5083 in 3.5 Wt.% NaCl solution.

Potentiodynamic polarization and electrochemical impedance spectroscopy are used to investigate the effect of Hg²⁺ on the corrosion behavior. The surface and cross-sectional morphology are characterized by scanning electron microscopy and energy dispersive spectroscopy (EDS) to further reveal the corrosion mechanism of Hg²⁺.

The results show that the corrosion behavior of the coating changes significantly as the concentration of Hg²⁺ increases from 5 to 30 μg/L. The corrosion production film can inhibit the corrosion process when Hg²⁺ concentration is in the range of 0.5–5 μg/L, while Hg²⁺ can promote the corrosion process significantly when its concentration reaches to 30 μg/L. The generation rate of dense oxide film on the coating surface is faster than dissolution rate when the concentration of Hg²⁺ is in the range of 0–5 μg/L, which makes the coating “self-healing” and thus slightly slows down the corrosion rate. The EDS analysis shows that excessive Hg²⁺ are preferentially deposited at locations with inhomogeneous electrochemical properties, which in turn accelerates corrosion.

The corrosion resistance of Al-based coatings is significantly affected by Hg²⁺ in seawater. Thus, it is important to explain the corrosion mechanism of Al–2%Zn coatings under the combined effect of Hg²⁺ and Cl⁻ in 3.5 Wt.% NaCl solution.

DISTINGUISHED CHEMIST TO OPEN CORROSION EXHIBITION. The work of the Ministry of Supply touches on corrosion in many ways. The need to provide the armed forces with equipment which can be maintained in good condition in field and, what is more difficult, in store, means that anti‐corrosive measures receive special study at the Ministry. In the aircraft field, in which the relationship between fatigue and corrosion is now well appreciated, research is making good progress. The contribution made by the Ministry in the general field of corrosion is well known and significant. We were especially gratified therefore to announce in Corrosion Technology last month that Sir Owen Wansbrough‐Jones, K.B.E., C.B., PH.D., F.R.I.C., Chief Scientist of the Ministry of Supply, will open the Corrosion Exhibition to be held at the Royal Horticultural Society's New Hall, London, S.W.1, April 27–30.

Niobium Nitride (NbN) was interesting material for its applications in the medicinal tools or tools field (corresponding to saline serum media) as well as in mechanical properties. The aim of this work was depositing NbN thin films on two types of substrates (stainless steel (SS304) and silicon (100)) using plasma technique at varied powers (100–150 W).

DC magnetron sputtering technique at different powers were used to synthesis NbN films. Film structure was studied using X-ray diffraction (XRD) pattern. Rutherford elastic backscattering and energy dispersive X-ray were used to examine the deposited film composition. The films morphology was studied via atomic force microscopy and scanning electron microscopy images. Corrosion resistance of the three NbN/SS304 films was studied in 0.9% NaCl environment (physiological standard saline).

All properties could be controlled by the modification of DC power, where the crystallinity of samples was changed and consequently the corrosion and microhardness were modified, which correlated with the power. NbN film deposited at higher power (150 W) has shown better corrosion resistance (0.9% NaCl), which had smaller grain size (smoother) and was thicker.

The NbN films have a preferred orientation (111) matching to cubic structure phase. Corrosion resistance was enhanced for the NbN films compared to SS304 substrates (noncoating). Therefore, NbN films deposited on SS304 substrate could be applied as medicinal tools as well as in mechanical fields.

The purpose of this study is to introduce mechanochemically prepared polyaniline anticorrosive additives. In primer coating technology, there is an increasing interest in the development of efficient anticorrosive additives which replace the conventional inorganic anticorrosive pigments like heavy metal chromates and phosphates normally added to primer paints for the coating on metals. Conducting polymers are found to be better alternatives.

Polyaniline phosphate is synthesized through solid-state conditions without using any solvent. The synthesized polyaniline phosphate is added in the primer formulation instead of zinc phosphate. Primers with different quantity of zinc phosphate are also formulated and studied for comparison. The comparison between their abilities to control corrosion of carbon steel were done with application of open-circuit potential monitoring, polarization and electrochemical impedance spectroscopy methods in 3.5 per cent NaCl solution.

Corrosion studies indicate that polyaniline phosphate can improve corrosion protection properties by taking part the passivation processes. The performance of polyaniline phosphate is better than zinc phosphate.

I certify that the results are from our original research and this paper is neither considered for publication elsewhere nor published previously.