Corrosion inhibition of iron in 1M HCl by 1-phenyl-5-mercapto-1,2,3,4-tetrazole

The effect of molecular structure on hydrogen permeation and the corrosion inhibition of mild steel in acidic solutions

Inhibition of the acid corrosion of steel by 4-amino-3-hydrazino-5-thio-1,2,4-triazoles

Effects of SDS and some alcohols on the inhibition efficiency of corrosion for nickel

In the present work the corrosion inhibition of mild steel in hydrochloric solution by Black pepper extract (Piper nigrum fem. Piperaceae) was studied. The techniques employed for study were mass loss measurements, poten- tiodynamic polarisation, linear polarization resistance and electrochemical impedance spectroscopy (EIS). The results ob- tained revealed that Black pepper extract was a good corrosion inhibitor for mild steel in hydrochloric acid medium and maximum inhibition efficiency (98%) was found at 120 ppm at 35 oC. Potentiodynamic polarization curves showed that black pepper extract is a mixed-type inhibitor. EIS showed that the charge transfer controls the corrosion process in inhib- ited solutions. Adsorption of the inhibitor on the mild steel surface followed Langmuir adsorption isotherm. The value of the free energy of adsorption, � Gads, indicated that the adsorption of inhibitor molecules was typical of chemisorption. The results obtained show that the Black pepper extract which mainly contains alkaloid 'Piperine' could serve as an excel- lent green inhibitor for corrosion of mild steel in acid solutions.

Green Approach to Corrosion Inhibition by Black Pepper Extract in Hydrochloric Acid Solution

Corrosion inhibition by 4-amino-3-H-5-mercapto-1,2,4-triazoline and some related compounds on the dissolution of mild steel in sulphuric acid solutions was measured using chemical and electrochemical methods. Polarization curves indicated that these compounds act as mixed-type inhibitors, that is, both the cathodic and anodic curves were affected. The effect of the structural changes in these compounds on their inhibition efficiency has been studied. Mass-loss measurements indicated that the rate of corrosion of mild steel rapidly increases with temperature over the range 25 – 60 °C both in the absence and in the presence of inhibitors, with an apparent activation energy in all instances of about 15 kcal mol -1 .

4-amino-3-substituted-5-mercapto-1,2,4-triazolines as inhibitors for the acid corrosion of steel

The corrision of steel in 2.5 N H 2 SO 4 in water-dimethyl formamide (DMF) solutions with various compositions (from 0.0 to 70 vol.% DMF) was studied. The rate of dissolution of steel was measured chemically using gasometry and mass-loss technique and electrochemically using d.c. polarization and a.c. impedance techniques. The results obtained showed that the acid corrosion of steel was inhibited by dimethyl formamide in the medium. Capacitance measurements indicated that the dimethyl formamide molecules were specifically adsorbed at the steel-solution interface. The effect of variation in the composition of the water-dimethyl formamide solution on the protection efficiency of 4-amino-3-H-5-mercapto-1,2,4-triazoline was also studied. The results showed that the protection efficiency of this inhibitor generally decreased as the concentration of DMF in the medium increased. It is suggested that there is competitive adsorption between the dimethyl formamide and the inhibitor molecules. An increase in the concentration of DMF in the solution leads to the displacement of adsorbed inhibitor molecules from the double layer at the steel-solution interface.

Acid corrosion of steel in water-dimethyl formamide solutions

The effect of heat treatment on the inhibition of acid corrosion of duralumin has been studied using gasometry, mass loss measurements and potentiodynamic technique. All the data reveal that the duralumin generally developed good corrosion resistance after heat treatment and the corrosion rate ranked as follows: Non treated > Naturally aged > quenched. This improvement in the corrosion resistance was attributed to the structural homogeneity of the heat-treated alloys. The presence of some selected aryl and alkyl triazoline derivatives at the thershold concentration of 5 × 10−3 M indicate that these compounds retard the corrosion rate of duralumin and the extend of inhibition depends on the molecular structure of the inhibitors. Polarization curves show that the triazoline compounds act as mixed-type inhibitors affecting both the cathodic and anodic process. Moreover, there is no noticeable difference in the degree by which the triazoline derivatives inhibit the corrosion of pure aluminium and heat treated duralumin alloy.

M. El-Gamal

Papers

4-amino-3-substituted-5-mercapto-1,2,4-triazolines as inhibitors for the acid corrosion of steel

Acid corrosion of steel in water-dimethyl formamide solutions

Effect of heat treatment on the Inhibition of the acidic corrosion of aluminum alloy