Corrosion inhibition of mild steel in acidic medium using hydrazide derivatives

Ethanedihydrazide as a Corrosion Inhibitor for Iron in 3.5% NaCl Solutions

Corrosion of iron in sodium chloride (3.5% wt) solutions and its inhibition by ethanedihydrazide (EH) have been reported. Electrochemical impedance spectroscopy (EIS), cyclic potentiodynamic polarization (CPP), and change of current with time at -475 mV (Ag/AgCl) measurements were employed in this study. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) techniques were utilized to report surface morphology and elemental analysis, respectively. The presence of 5 × 10-5 M EH was found to inhibit the corrosion of iron, and the effect of inhibition profoundly increased with an increase in EH concentration up to 1 × 10-4 M and further to 5 × 10-4 M. The low values of corrosion current and high corrosion resistance, which were obtained from the EIS, CPP, and change of current with time experiments, affirmed the adequacy of EH as a corrosion inhibitor for iron. Surface investigations demonstrated that the chloride solution without EH molecules causes severe corrosion, while the coexistence of EH within the chloride solution greatly minimizes the acuteness of chloride, particularly pitting corrosion.

Enhanced corrosion inhibition properties of carboxymethyl hydroxypropyl chitosan for mild steel in 1.0 M HCl solution

CHPCS was synthesized and showed better corrosion inhibition than HPCS (corrosion inhibition of 95.3%); its corrosion inhibition mechanism is presented.

Solvent Free Synthesis of Four Cationic Surfactants: Evaluation of Their Corrosion Inhibition Properties on Zinc Phosphate Conversion Coating on Mild Steel

Four cationic surfactants have been synthesized in the absence of solvent using triethylamine and four different long chain alkyl halides. Using FTIR, 1H NMR spectra and elementary analysis the chemical structure of the synthesized surfactants were confirmed. The physio-chemical properties have been evaluated using standard analytical procedures. The corrosion inhibition properties of these four surfactants as additives were evaluated on zinc phosphate conversion coating on mild steel using nano silica as accelerator. The efficacy of the surfactants as corrosion inhibitor increases with increase in the side chain length and surface activity. With the help of X-ray diffraction (XRD), Atomic force microscope (AFM) and Scanning electron microscope (SEM) the surface morphology have been studied. The protective performance of the coatings was evaluated by salt spray exposure studies.

Corrosion Inhibition Effect of 4-Hydroxy-N′-[(E)-(1H-indole-2-ylmethylidene)] Benzohydrazide on Mild Steel in Hydrochloric Acid Solution

The inhibition performance and adsorption behaviour of 4-hydroxy-N′-[(E)-(1H-indole-2-ylmethylidene)] benzohydrazide (HIBH) on mild steel in 1 M HCl solution were tested by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The inhibition efficiency of HIBH increases with increase in inhibitor concentration in the temperature range 30–60°C. Polarisation curves indicate that HIBH is a mixed inhibitor, affecting both cathodic and anodic corrosion currents. The adsorption process of HIBH at the mild steel/hydrochloric acid solution interface obeyed Langmuir adsorption isotherm model and inhibition takes place by mixed adsorption, predominantly chemisorption. The activation and thermodynamic parameters for the corrosion inhibition process were calculated to elaborate the mechanism of corrosion inhibition.

N′-(Phenylsulfonyl)isonicotinohydrazide monohydrate

In the title compound, C₁₂H₁₁N₃O₃S·H₂O, the pyridine ring makes a dihedral angle of 24.78 (14)° with the phenyl ring. Intra­molecular N—H⋯O and inter­molecular O—H⋯O hydrogen bonds are observed and stabilize the packing in the crystal structure.