Corrosion and Dye

Formazan of benzaldehyde (FB) has been prepared as a corrosion inhibitor to control the rate of corrosion. This compound has been investigated as corrosion inhibitor at room temperature for preventing mild steel corrosion in Citric acid mediums by weight loss method and by adsorption isotherm. The result showed that the corrosion inhibition efficiency of these compounds was found to vary with different acid concentration. Also, it was found that the corrosion inhibition behavior of FB is greater in 1M Citric acid and 2M Citric acid. But when it has been compared the results revealed that the inhibitor efficiency is better in 1M Citric acid than 2M Citric acid. So FB can be used has a good inhibitor for preventing mild steel material. The surface analysis study also confirms that the corrosion of the mild steel and its inhibition efficiency by the inhibitor FB.

In this work, Khillah extract was examined as green corrosion inhibitor for zinc in 3.5 % NaCl and 16 ppm solution by using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. Results obtained showed that the extract of Khillah functioned as an effective and good inhibitor. The inhibition efficiency was found to increase with increase of extract concentration reaching maximum inhibition efficiency 87.2%. The adsorption of the inhibitor molecules on the zinc metal surface obeyed Langmuir adsorption isotherm. Polarization data indicated that this extract acts as mixed type inhibitor.

Inhibition of C-steel corrosion by metal-organic frameworks containing heterocyclic ligand of Ag (I) in 1 M HCl was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) measurements. The inhibition efficiency increased with increase in inhibitor concentration but decreased with rise in temperature. The thermodynamic parameters of corrosion and adsorption processes were determined and discussed. The adsorption of these inhibitors was found to obey Temkin’s adsorption isotherm. Whereas thermodynamic suggested that a physisorption process occurred.The surface morphology of carbon steel sample was investigated by scanning electron microscopy (SEM).

A passive conversion layer was fabricated from C2 solution (with the composition of 5g Cr(III)/ L, compound producing complex 16 g/L, pH = 9) containing nano-silica particles with the content of 5 g/L, on zinc coated samples denoted as M9-5. In this condition, silica particles were dispersed well in the solution with the particles size of about 87 nm. M9-5 samples do not contain a toxic component of Cr(VI) and were significantly reinforced in anti-corrosion ability in comparison to the zinc coated samples. In addition, M9-5 samples have ability to self correct when it is scratched. This ability is the most important property of conversion layer which can reinforce the anti-corrosion property of the samples.

Benzotriazole has been prepared as a corrosion inhibitor to control the rate of corrosion. This compound has been investigated as corrosion inhibitor at room temperature for preventing mild steel corrosion in Sulphuric acid medium at different concentration at two hour time interval by weight loss method. The result showed that the corrosion inhibition efficiency of these compounds was found to vary with Sulphuric acid concentration. Also, it was found that the corrosion inhibition behavior of Benzotriazole is greater in 1M H2SO4 when compared to 2M H2SO4 at two hour time interval. So Benzotriazole can be used has a good inhibitor for preventing mild steel material for many construction purpose.

Abstract The corrosion inhibition and adsorption process of D - Tryptophan (DT) on mild steel in 2 HCl was studied by means of chemical (weight loss), electrochemical and quantum chemical techniques. The inhibition efficiency increases with decreasing temperature and increasing concentration of inhibitor. It has been determined that the adsorption of DT on mild steel obeys the Temkin adsorption isotherm at all studied temperatures with negative values of ?Goads, suggesting a stable and a spontaneous inhibition process. In potentiodynamic polarization, the curves shifted towards lower current density in the presence of the DT with well-defined Tafel regions suggesting that the inhibitor retard the corrosion process without changing the mechanism of the corrosion process; and exhibit cathodic and anodic polarization (mixed type inhibitor) because the change in Ecorr is less than 85 vM/SCE with respect to the blank. Corrosion current density was calculated by extrapolation of the linear parts of these curves to the corresponding corrosion potential; and corrosion potential (Ecorr), corrosion current densities (icorr), anodic Tafel slope (?a), cathodic Tafel slope (?b) were determined with maximum value of inhibition efficiency for 5 x 10-4 M concentration of the inhibitor at 303 K was 78.4%. Quantum chemical calculations were performed using Density Functional Theory (DFT) with the help of complete geometry optimization for theoretical calculations of EHOMO, ELUMO, and energy gap (?E). Inhibition efficiency increases with increasing EHOMO indicating that the molecule has tendency to donate electrons to the mild steel with low energy empty molecular orbital; whereas low value of ELUMO suggests that the molecule easily accepts electrons from mild steel.

The effect of addition of Santalum paniculatum leaves extract on the corrosion of steel in 0.5M H₂SO₄ acid has been studied by weight loss measurements, potentiodynamic polarisation and Electrochemical Impedance Spectroscopy (EIS) measurements. The inhibition efficiency was found to increase with inhibitors content to attain 59.38% and 91.66% Santalum paniculatum leaves extract on and 25ppmTBAB respectively. Data obtained from EIS studies were analyzed to determinate the model inhibition process through appropriate equivalent circuit models. Inhibition efficiency IE (%) obtained from the various methods is in good agreement.

The inhibitive effect of the extract of Solanum torvum leaves on the corrosion of aluminium in 1M NaOH solution was studied using at weight loss method at 30 - 60?C. The extract acts as an excellent corrosion inhibitor with 91% efficiency at the highest concentration in the alkaline environment and the inhibition efficiency increased with increasing concentration of the extract. The adsorption of the inhibitor on aluminium surface decreases with rise in temperature, suggesting physical adsorption of the organic matter on the metal surface. These results were supported by kinetic and thermodynamic parameters for corrosion and adsorption processes calculated from the experimental data at the various temperatures studied.

The hindrance corrosion of Carbon steel in one molar Hydrochloric acid by Levofloxacin antibiotic was considered utilizing Electrochemical techniques ( EIS, EFM, and Tafel plots) and Chemical (WL, HE and thermometric) at 25ºC. The inhibitor was adsorped on metal surface is steady with Langmuir isotherm adsorption. The curves of polarization reveal that the expansions of Levofloxacin movements the cathodic and anodic branches towards lower currents. Such moves demonstrate that Levofloxacin goes about as a mixed inhibitor. The thermodynamic elements of adsorption procedures were ascertained from weight loss at distinctive temperatures information were utilized to analyses the mechanism of drug. The surface morphology of the metal examples was evaluated using (EDX and SEM) analysis.

Expired drug (non-toxic characteristics) was used as corrosion inhibitors for mild steel in 1 M HCl medium was studied by weight loss and electrochemical methods. Effect of temperature was investigated at temperature range (303-343 K).The obtained results reveals that, the inhibition efficiency increases with increases of concentration of the inhibitor. Polarization curves indicated that they are mixed – type of inhibitor. The data collected from Thermodynamic studied are in good agreement to confirm the ability of using expired LF drug acts as corrosion inhibitors for mild steel in hydrochloric acid corrosive medium.