Browsing by Author "M. Naoun"

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    Characterization of electrodeposited Ni–MoS2 composite coatings under the influence of current density
    (S.C. Virtual Company of Physics S.R.L, 2021-07-08) A. Ganaa; H. Ben Temama; F. Lekmine; M. Naoun; O. Herzallaha
    In this paper, the influence of current density on electrodeposited Ni–MoS2 composite coatings has been studied for the first time. Low carbon steel alloy has been selected as a substrate. The Ni–MoS2 composite coatings are deposited at a temperature of 48 °C with applied current densities of (1, 2, 3 and 4 A/dm2). The x-ray diffraction (XRD) analysis of electrodeposited Ni– MoS2 coatings depicts a number of sharp peaks indicating a good crystallinity. Using ASTM database, the peaks at 14°, 32°, 33°, 39°, 49° and 58° correspond to (200), (100), (101), (103), (105) and (110) hkl planes respectively. The morphology was examined by scanning electron microscopy (SEM). Microhardness measurements show that all Ni–MoS2 samples are harder than low carbon steel substrate. EDX analysis of the Ni–MoS2 composite confirmed that the fraction of MoS2 increased with the increase of applied current density. The study of corrosion properties was carried out in a 0.6M NaCl solution. The potentiodynamic polarization curve of electrodeposited Ni–MoS2 confirmed that the corrosion resistance increases with the decrease of applied current density. In addition, Electrochemical tests show that the optimal value of applied current density is 3 A/dm2 in the sense of the least value of Ecorr = -314,1 mV and the best resistance was Rp = 9.52 K.cm2.
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    Effects of Current Density on Ni–P Coating Obtained by Electrodeposition
    (Metallophysics and Advanced Technologies, 2021-08-02) F. Lekmine; K. Digheche; M. Naoun; H. Bentemam; A. Gana
    In this work, Ni–P coatings are deposited on the steel substrate by electro-deposition from a solution containing nickel sulfate and sodium hypophos-phite (NaH2PO2). The effect of the current density on the morphology, phase structure, microhardness, and corrosion performance of the Ni–P coatings are studied. Scanning electron microscopy and energy dispersive X-ray anal-ysis and X-ray diffraction are used to study the morphological, composition and phase structure. The corrosion performance of the coatings is evaluated by weight loss, electrochemical impedance spectroscopy and Tafel polariza-tion. Results showed that the morphology of the electrodeposited Ni–P alloys coatings has spherical grains for all the samples, and the Ni3P phases are formed all over the microstructure of the coatings. It is observed that the phosphorus content and microhardness are dependent on the current density. The corrosion tests show that 5 A⋅dm−2 current density is the optimal value which gives the best protective coating against corrosion. It also exhibits su-perior microhardness originated from the higher Ni3P amount.
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    Mechanical Characterization of Electrodeposition of Ni-P Alloy Coating
    (JOURNAL OF NANO- AND ELECTRONIC PHYSICS, 2020-02-25) F. Lekmine; H. Ben Temam; M. Naoun; M. Hadjadj
    The electrodeposition process plays a crucial role in the formation of thin films on materials, in particular, the electrodeposition of nickel-phosphorus because of its important properties. In this study, Ni-P coatings were deposited on X52 steel substrates by electrodeposition technique from a solution containing nickel sulfate, sodium hypophosphite (NaH2PO2). Composition, surface morphology, and mechanical properties of the Ni-P deposits were studied using SEM, EDAX, the Vickers method, weight loss and potentiodynamic polarization techniques. The effects of the current density were investigated on the surface morphology, phosphorus content, microhardness and corrosion of the coatings. It was observed that both the phosphorus content and microhardness are dependent on the current density. Results demonstrate that the morphology of the electrodeposited Ni-P alloys shows that the grains are spherical in nature for all the samples. It has been observed that the influence of current density on the P content of the deposit is an inverse relation with phosphorous content and also the as-plated coatings at current density of 5 Am − 4 exhibit the superior microhardness. Corrosion tests show that 5 Am − 4 is the best current density value which gives the best protection coating against corrosion.
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    Structural, Mechanical and Corrosion Behavior of Ni-P-TiO2 Composite Coatings: Effect of Current Density
    (JOURNAL OF NANO- AND ELECTRONIC PHYSICS, 2021-02-28) 1. LEKMINE Farid; M. Naoun; A. Gana; H. Ben Temam
    Ni-P-TiO2 composite coatings are important in engineering due to their properties such as good resistance to wear and corrosion, magnetic properties, electrical and thermal conductivity. In this paper, the effect of current density on electrodeposited Ni-P-TiO2 composite coatings was investigated for the first time. Ni-P-TiO2 composite coatings were deposited with applied current densities (1, 3, 5, 7 and 9 A·dm – 2) on copper substrates. X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and microhardness analysis were used to study the morphological, microstructural and mechanical properties. On the other hand, the corrosion performance of the coatings was evaluated using Tafel polarization and electrochemical impedance spectroscopy (EIS). XRD results indicate that the inclusion of TiO2 nanoparticles into the coatings alters the relative intensity of Ni peak as well as peak breadth. In addition, microhardness of the coatings noticeably increased with current densities. Ni-P-TiO2 composite coating electrodeposited at 3 A·dm – 2 exhibits the best microhardness and corrosion resistance.