The effect of ethylenediaminetetraacetic acid (EDTA) as a capping agent on the structure, morphology, optical, and magnetic properties of nickel oxide (NiO) nanosized particles, synthesized by coprecipitation method, was investigated. Nickel chloride hexahydrate and sodium hydroxide (NaOH) were used as precursors. The resultant nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). XRD patterns showed that NiO have a face-centered cubic (FCC) structure. The crystallite size, estimated by Scherrer formula, has been found in the range of 28–33 nm. It is noticed that EDTA-capped NiO nanoparticles have a smaller size than pure nanoparticles. Thus, the addition of 0.1 M capping agent EDTA can form a nucleation point for nanoparticles growth. The optical and magnetic properties were investigated by Fourier transform infrared spectroscopy (FTIR) and UV-vis absorption spectroscopy (UV) as well as electron paramagnetic resonance (EPR) and magnetization measurements. FTIR spectra indicated the presence of absorption bands in the range of 402–425 cm−1, which is a common feature of NiO. EPR for NiO nanosized particles was measured at room temperature. An EPR line withgfactor ≈1.9–2 is detected for NiO nanoparticles, corresponding to Ni2+ions. The magnetic hysteresis of NiO nanoparticles showed that EDTA capping recovers the surface magnetization of the nanoparticles.

The inhibitive action of plant leaf extracts, Crataegus oxyacantha (Hawthorn) and Prunus Avium (Sweet Cherry) on the corrosion of mild steel in 0.5 M HCl solution was investigated using open circuit potential-time measurements (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Functional groups of these plants' leaf extracts and their absorption bands were identified by Fourier transform infrared spectroscopy (FTIR) and Ultra-Violet Spectrophotometer (UV), respectively. The leaf extracts showed good inhibition efficiency in hydrochloric acid solution. Potentiodynamic polarization curves revealed that Crataegus oxyacantha and Purnus Avium plants leaves extracts acted as mixed type inhibitors. Theoretical fitting of different isotherms, Langmuir, Florry-Huggins and the kinetic-thermodynamic models was tested to describe the mode of inhibitors' adsorption on mild steel surface. UV spectra proved that the inhibiting action takes place through simple physical adsorption of the extracts molecules on mild steel surface.

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The influence of SnO 2 nanoparticles addition on the corrosion and capacitive behaviour of (SnO 2 ) x (Bi,Pb)-2223, where x=0.00, 0.025, and 0.1wt. % phase superconductor in 0.1 mol L -1 Na 2 SO 4 at 30 0 C was studied using potentiodynamic polarization curves measurements, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques. . The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as scanning electron microscopy (SEM). XRD patterns showed that nano-sized SnO 2 are located at the surface and grains boundaries reducing the voids present in the (Bi,Pb)-2223 matrix as displayed by SEM photographs. Such fact is confirmed by TEM images that also assured the presence of nanosized SnO 2 particles in the phase matrix. The electrochemical techniques showed that the corrosion current density (i corr ) decreases with increasing both SnO 2 nanoparticles percentages and the time elapsed from the preparation of superconductor samples. Cyclic voltammetry (CV) measurements showed that 0.025% SnO 2 containing superconductor is a good choice for electrochemical capacitor applications. The corrosion process was found to be controlled not only by charge transfer, but also by the diffusion process.