Adsorption and inhibition behavior of a novel Schiff base on carbon steel corrosion in acid media

In this study, the inhibition effect of 2,2′-(heptane-1,7-diylbis(azanylylidene)bis-(methanylylidene))diphenol (HAMD) on carbon steel corrosion in 0.5 mol L−1 H2SO4 solution was studied. Weight loss and electrochemical techniques such as open circuit potential (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to inspect the efficiency of HAMD as corrosion inhibitor. Scanning electron microscopy (SEM) and energy dispersion X-ray (EDAX) were used to characterize the steel surface. Polarization measurements indicated that, the studied inhibitor acts as mixed-type inhibitor. The adsorption of HAMD molecules on the carbon steel surface obeys Langmuir adsorption isotherm

Influence of surface modified nanoilmenite/amorphous silica composite particles on the thermal stability of cold galvanizing coating

The present approach investigates the use of novel nanoilmenite/amorphous silica composite (NI/AS) particles fabricated from ilmenite nanoparticles (FeTiO3 NPs) and synthesized amorphous silica grains to improve thermal stability of the cold galvanizing coating. Transmission electron microscopic (TEM) images demonstrated that both nanoilmenite and nanocomposite particles were of flaky-like nature and the average diameter of the particles is 20 nm. The lamellar shape of the nanocomposite and spherical nature of Zn-dust particles were illustrated by scanning electron microscopy (SEM) micrographs. Different alkyd-based cold galvanizing coating formulations were modified using uniformly dispersing various amounts of the processed nanocomposite particles as a modifier to form some engineering nanocomposite coatings. Thermal stability of the nanocomposite and Zn-dust particles was determined by thermo-gravimetric analysis (TGA). From the obtained results it could be observed that the weight loss (%) as a feature of the thermal stability in case of the nanocomposite particles was 2.9 compared to 85.9 for Zn-dust powder grains. Derivative thermo-gravimetric (DTG) measurements were done under nitrogen atmosphere for the cured cold galvanizing coating samples heated from room temperature to 1000 °C. The obtained results revealed that the maximum decomposition temperature point in the third degradation step for 6% nanocomposite surface modified cured sample (CG-F) was detected at 693 °C and was less value for unmodified conventional cold galvanizing coating (CG-A) at 612 °C. The increase in thermal stability with increasing the concentration of nanocomposite particles could be mainly attributed to the interface surface interaction between the nanocomposite particles and alkyd resin matrix in which enhancing the inorganic-organic network stiffness by causing a reduction in the total free spaces and enhancement in the cross-linking density of the cured film then, requires high energy to cleave it. Keywords: Nanoilmenite/amorphous silica composite, Cold galvanizing coating, Thermal stability, TEM, TGA, DT

Synthesis of some novel non ionic surfactants based on tolyltriazole and evaluation their performance as corrosion inhibitors for carbon steel

Five new synthesized non ionic surfactants (I–V) were synthesized and characterized using FTIR and NMR spectroscopic methods. Performance of the synthesized compounds as corrosion inhibitors for X- 65 type carbon steel in oil wells formation water was investigated by various techniques such as weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). It was found that the percentage inhibition efficiency (η%) increases by increasing the inhibitor concentration until the critical micelle concentration (CMC) is reached. Also, the results showed enhancement in inhibition efficiencies with increasing both molecular size of the surfactant and the degree of ethoxylation. Potentiodynamic polarization curves indicated that the inhibitors under investigation act as mixed type. The data obtained from electrochemical impedance spectroscopy (EIS) were analyzed to model the corrosion inhibition process through equivalent circuit. Finally, the nature of the protective film formed on carbon steel surface was analyzed by SEM and EDX techniques