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Two chemical solutions NH₄F:H₂O:C₃H₈O₃(sol${}_1)$ and NH₄F:H₂O:C₂H₆O₂(sol${}_2)$ with different fluoride ratios were used separately in an anodic process to study the morphological characteristics of the produced copper oxides. Glycerol and ethylene glycol were utilized as inhibitions to slow down the activity of fluoride ions. The rest of the anodization process parameters were constant. Scanning electron microscope (SEM) images showed the formation of Cu₂O microcubes when sol₁ was used. The utilization of sol₂ produced octahedral Cu₂O as well as cubes and spherical structures. The increase of NH₄F in sol₁ led to a reduction in the volumes of Cu₂O microcubes, and in sol₂, it produced incomplete octahedral Cu₂O. Since ethylene glycol has a lower viscosity than glycerol, copper corrodes more quickly in the presence of the former than in the latter. The findings indicate that sol₁ is experiencing a higher current flow than sol₂. The relationship between current and time is semi-constant at low applied voltage, but the two curves behave differently when applying high voltage in the early stages.

Essential oil from Artemisia herba alba (Art) was hydrodistilled and tested as corrosion inhibitor of steel in 0.5 M H₂SO₄ using weight loss measurements and electrochemical polarization methods. Results gathered show that this natural oil reduced the corrosion rate by the cathodic action. Its inhibition efficiency attains the maximum (74%) at 1 g/L. The inhibition efficiency of Arm oil increases with the rise of temperature. The adsorption isotherm of natural product on the steel has been determined. A. herba alba essential oil was obtained by hydrodistillation and its chemical composition oil was investigated by capillary GC and GC/MS. The major components were chrysanthenone (30.6%) and camphor (24.4%).

The focus of this study is to synthesize a new calixarene derivative namely calix[6]arene (C21) and to test its performance as corrosion inhibitor of C38 steel in molar HCl at 308 K. Polarization and weight loss measurements were used. Weight loss tests show that C21 retards until to stop corrosion phenomenon at 5 × 10^-5M. C21 is an excellent inhibitor and its inhibition efficiency increases with its concentration to reach 100% since 5 × 10^-5M. Polarization curves revealed that C21 affects both cathodic and anodic domains by decreasing current densities and then it may be classified as a mixed type inhibitor. The calixarene tested is adsorbed on the surface according to the Langmuir adsorption isotherm. Free enthalpy of adsorption reveals that C21 acts from chemisorption onto the steel surface.

This paper describes the inhibition effect of 1-benzyl piperazine (P1) and bis(1-benzyl piperazine) thiuram disulfide (P2) towards the corrosion of C38 steel in 5.5 M H₃PO₄ solution by potentiodynamic polarization and weight loss methods. The influence of inhibitor concentration and temperature on inhibitory behavior of P2 were investigated. The inhibition efficiency (IE) was found to be dependent on the type of piperazine and its concentration. The IE for 10^-3 M P2 in 5.5 M H₃PO₄ is greater than 98%. Polarization studies clearly revealed that both P1 and P2 act as mixed-type inhibitors. Adsorption isotherms were fitted by the Langmuir isotherm. Adsorption energies ( and ) were evaluated. Kinetic parameters were determined.

Dodecylamine spontaneously adsorbs on carbon steel via its polar group (-NH₂) in hydrochloric acid solution. Furthermore, it forms a monolayer film on carbon steel surface. The inhibition mechanism of dodecylamine for carbon steel is geometric blocking effect. The adsorption of dodecylamine on carbon steel surface follows Arrhenius equation. The adsorption slightly increases activated energy, but greatly reduces pre-exponential factor value. Atomic force microscopy force curves indicate that at the area without adsorbed dodecylamine, no obvious adhere force occurs. At the area with adsorbed dodecylamine, however, an average 1.3 nN adhere force is observed.

The inhibition effect of synthesized N′-(phenylmethylidene)-2-(2-methyl-1H-benzimidazol-1-yl)acetohydrazides, N′-(4-methylphenylmethylidene)-2-(2-methyl-1H-benzimidazol-1-yl)acetohydrazides, and N′-(4-methoxyphenylmethylidene)-2-(2-methyl-1H-benzimidazol-1-yl)acetohydrazides on the corrosion behaviour of N80 steel in 15% hydrochloric acid solution was investigated using weight loss, potentiostatic polarization and electrochemical impedance spectroscopy methods. The inhibition efficiency increased as the concentration of the inhibitors was increased. The effect of temperature on corrosion inhibition was investigated by weight loss method and thermodynamic parameters were calculated. Potentiodynamic polarization measurements show that all the three studied inhibitors act as mixed inhibitor. The adsorption of inhibitors on N80 steel surface obeys Langmuir adsorption isotherm. The structure of inhibitors was optimized using semiemperical AM1 method. Theoretical parameters such as the highest occupied molecular orbital (E_HOMO), lowest unoccupied molecular orbital (E_LUMO) energy levels, energy gap (ΔE = E_LUMO - E_HOMO), dipole moment (μ), global hardness (γ), softness (σ), binding energy, molecular surface area and the fraction of electrons transferred (ΔN) were calculated and the adsorption mechanism was discussed. Scanning electron microscopy was used to characterize the surface marphology of the N80 steel.