Corrosion Inhibition of Carbon Steel in hydrochloric acid medium using Gliclazide drug

  • Tab. 4: Thermodynamic variables for the dissolution of CS in 1 M HCl in the nonexistence and existence of varied doses measurements of investigated drug
    Tab. 4: Thermodynamic variables for the dissolution of CS in 1 M HCl in the nonexistence and existence of varied doses measurements of investigated drug
The role of Gliclazide as corrosion drugs for CS in 1 M HCl have been studied by using weight loss (WL), Hydrogen evaluation (HE), potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS) and Electrochemical frequency modulation (EFM) techniques. Weight loss (WL) studied at various temperatures between (25 – 45oC) but Hydrogen evaluation (HE), Open circuit potential (EOCP) and all electrochemical studied at 25oC and seen that the gliclazide studied are mixed type drug. The effect of temperature on corrosion inhibition, the activation and the thermodynamic of adsorption parameters were determinate. Electrochemical impedance was utilizing to examine the inhibition of corrosion and the mechanism. The existence of the Gliclazide in the solution rise the charge transfer resistance and reducing the capacitance of the double layer. The adsorption of the Gliclazide on the surface of CS was found to obey with Langmuir adsorption isotherm and discussed the thermodynamic parameters (ΔGo, ΔHo and ΔSo) that were determinate. The morphology of inhibition of Gliclazide on CS surface was analyzed by scanning electron microscope (SEM) technology, energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM), all examine techniques illustrate the formation of thin film from Gliclazide inhibitor adsorbed on the metal surface.It was found the adsorption process is spontaneous and increases, with increasing of inhibition efficiency.


Malonic Acid as Corrosion Inhibitor for Carbon Steel in 1 M Hydrochloric Acid Solutions

The protection effect of malonic acid on carbon steel corrosion was studied in aerated stagnant 1M HCl solutions at 250C. Measurements were conducted under different experimental conditions using weight loss, Tafel polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. malonic acid was found to be good inhibitor of carbon steel corrosion in1 M HCl. The adsorption of this inhibitor is found to obey the Langmuir adsorption isotherm. The calculated activation energies proposed that the inhibitor molecules being physically adsorbed onto the metal surface. Polarization data revealed that this compound behave as mixed type inhibitor.


Adsorption and Corrosion Inhibition Characteristics of Some Thiophene-3-Carbohydrazide Derivatives on Low Carbon Steel in Hydrochloric Acid Solutions

Fig. 7: Molecular orbital plots of organic compounds

New compounds of corrosion inhibitors namely amino-N’-(3-(hydroxyimino)butan-2-ylidene)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbohydrazide (1), amino-N’-(thiophen-2-ylmethylene)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbohydrazide (2) and amino-N’-(1-(pyridin-2-yl)ethylidene)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbohydrazide (3) were synthesized and its inhibiting action on the corrosion of carbon steel in 1 M hydrochloric acid at 25ºC was investigated by various corrosion monitoring techniques. A Potentiodynamic polarization, AC impedance and electrochemical frequency modulation methods have been used. Potentiodynamic polarization studies showed that these derivatives were mixed type inhibitors. The effect of temperature on the corrosion behavior of carbon steel in 1 M HCl with the addition of these compounds were studied in the temperatures 25 and 45ºC. The adsorption of these inhibitors on carbon steel surface from hydrochloric acid obeyed the Langmuir adsorption isotherm. Quantum chemical method is used to explore the relationship between the inhibitors molecular properties and their inhibition efficiency.