A STUDY OF CORROSION INHIBITON EFFECT OF THIOSEMICARBAZIDE BASED SCHIFF BASE ON ALUMINIUM METAL IN ACIDIC MEDIUM

Corrosion is the destruction of metal surface by the reaction with its environment (humidity, gases, acid, alkaline etc.). In this process metal convert in to the more stable form such as sulphide oxide etc. Corrosion of materials and structures is a hindrance to the development of society as it causes significant loss to the economy, leads to pollution, and leads to serious disasters, hence its prevention and control is of great benefit for the humanity. Addition of corrosion inhibitors is one of the practical and easy methods to protect metals and alloys against attack of corrosion in many industrial environments. In this chapter thiosemicarbazide based Schiff base 2-[(3,4-dihydroxy-5-nitrophenyl)methylidene]hydrazine1-carbothioamide (DHNPMHC) was synthesized and characterized using elemental analysis, FT-IR and UV–Vis methods. The inhibition efficiency of Schiff base DHNPMHC against aluminium corrosion in 0.5 M HCl was examined using mass loss measurement and scanning electron microscopy (SEM). Results showed that DHNPMHC is an effective inhibitor for aluminium corrosion in 0.5 M HCl solution. The inhibition efficiency also increased with concentration of inhibitor increased. Maximum percentage inhibition efficiency 92.6 % (at 4-hour immersion time) is shown at highest concentration of inhibitor 5% (5X10-5M). Adsorption of the inhibitor on the aluminium surface followed Langmuir adsorption isotherm. SEM study of aluminium surface in presence of inhibitor and in absence of inhibitor also supports the inhibition of corrosion in acidic medium. All results show that the Schiff base of thiosemicarbazide (DHNPMHC) is excellent corrosion inhibitor for aluminium in 0.5 M HCl.

Experimental Evaluation for the Inhibition of Carbon Steel Corrosion in Salt and Acid Media by New Derivative of Quinolin-2-One

The inhibition ability of the new derivative (quinolin-2-one), namely (1-{[5-(2-Chloro-phenylazo)-2- hydroy-benzylidene]-amino}-4,7-dimethyl -6-nitro- 1H-quinolin-2-one (CPHAQ2O)) towards carbon steel corrosion in (3.5% NaCl) and (0.5M HCl) solutions were evaluated by potentiodynamic polarization at different inhibitor concentrations. Polarization curves showed that the evaluated compound acted as mixed inhibitors, and the adsorption of the evaluated inhibitor obeys the Langmuir adsorption isotherm in both salt and acid solutions. The results revealed that the percentage inhibition efficiency (%IE) in the salty solution (90.55%) is greater than that in the acidic solution (77.62%). The surface changes of the carbon steel and the film persistency of the inhibitor were studied using SEM (Scanning Electron Microscopy).

3-Mercaptopropionic Acid as Corrosion Inhibitor for Carbon Steel in CO2 Aerated 1% NaCl Solution with Buffer Control-pH

In this research, 3-Mercaptopropionic acid (MPA) as corrosion inhibitor of carbon steel in CO2 aerated 1% NaCl solution with buffer pH adjustment has been studied by means of electrochemical impedance (EIS) and polarization (Tafel plot). MPA was found to be an effective carbon steel inhibitor. Percentage inhibition efficiency (IE %) calculated by both Tafel plot and EIS, ranged from 85% to 90%. MPA was found to affect the cathodic processes and act as cathodic-type inhibitors. Mechanism of inhibit corrosion by adsorption mechanism leads to the formation of a protective chemisorbed film on the metal surface film which suppresses the dissolution reaction and the hydrogen evolution reaction is activation controlled.

Adsorption and corrosion inhibition behavior of stainless steel 316 by aliphatic amine compounds in acidic solution

Gravimetric and electrochemical measurements were performed to investigate the effectiveness of an aliphatic amine compound with trade name of Armohib 28. It was found that the percentage inhibition efficiency increased with the increase of the compound concentration. Polarization curves indicate that the inhibitor under investigation acts as cathodic type which retards the rate of corrosion reactions by adsorbing on to the steel surface according to Langmuir adsorption isotherm. The activation energy and thermodynamic parameters were calculated and analyzed. The data obtained from electrochemical impedance spectroscopy (EIS) were analyzed to model the corrosion inhibition process through equivalent circuit.

Corrosion Inhibition and Adsorption Behavior of Clove Oil on Iron in Acidic Medium

Corrosion behavior of iron in hydrochloric acid solution was studied using weight loss as well Scanning electron microscopy study without and with clove oil. The percentage inhibition efficiency increases with increasing clove oil concentration. All the data revel that the oil acts as an excellent inhibitor for the corrosion of iron in HCl solution. Thermodynamic, kinetic parameters and equilibrium constant for adsorption process were calculated from the experimental data. The adsorption of clove oil on experimental metals was found to follow the Langmuir adsorption isotherm at all the concentration studies. Scanning electron microscope (SEM), investigations also indicate that clove oil greatly lowers the dissolution currents.

Corrosion inhibition of 1018 carbon steel with some ethoxylated fatty amides in hydrochloric acid solution

The effect of three compounds of ethoxylated fatty amides with different number of ethylene oxide unit on the corrosion of 1018 carbon steel in 1M HCl has been studied using weight loss and galvanostatic polarization measurements. The percentage inhibition efficiency was found to increase with increasing concentration of inhibitor, number of ethylene oxide unit and with decreasing temperature. The inhibitive effect of these compounds was explained on the basis of adsorption on the metal surface, through their ethoxy groups. The adsorption process follows Langmuir adsorption isotherm. The effect of temperature on the rate of corrosion in the absence and presence of these compounds was also, studied. Some activated thermodynamic parameters were calculated.