Browsing by Author "Aissani Linda"

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    Effect of Film Thickness on the Structural and Tribo-Mechanical Properties of Reactive Sputtered Molybdenum Nitride Thin Films
    (Metallurgical and Materials Engineering Association of Metallurgical Engineers of Serbia AMES, 2022-06-05) Abboudi Abdelaziz; Aissani Linda; Saoudi Abdenour; Djebaili Hamid
    The current study aims to examine the impact of nitrogen content and film thickness on the structural and tribo-mechanical characteristics of reactive sputtered MoN thin films. Molybdenum nitride thin films with thicknesses ranging from 0.2 to 1.25 m have been applied to steel and silicon substrates for this purpose, with various amounts of controlled atmosphere (Ar+N2). Then, the films are characterized using XRD (X-ray diffraction), EDX (energy dispersive X-ray analysis), SEM (scanning electron microscopy), FTIR (Fourier-transform infrared spectroscopy), and nanoindentation. The residual stress was measured using the Stoney formula. Results show that a high compressive residual stress of -5.7 GPa is present in the film with a 0.3 μm thickness and gradually decreases with increasing film thickness. Above 1 µm of film thickness, there is no change in the density of the MoN films. Also, the coating hardness and Young’s modulus vary between 9.5 and 35 GPa, and 266 and 320 GPa, respectively, depending on nitrogen content and film thickness. Lastly, the friction of the MoN thin films is estimated to be around 0.55, which proves that the oxide is being slowly removed.
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    Influence of the carburization time on the structural and mechanical properties of XC20 stee
    (Mater. Res. Express, 2021-08-21) Saoudi Abdenour; Aissani Linda; Chahaoui Oualid; Bestandji Ali; Louafi Med Salah; Djebaili Hamid
    This study focuses on the effect of carburization time on the structural and mechanical properties of low carbon XC20 mild steel(C. Wt.% <0.25). The XC20 steel was carburized with activated carbon with a carbon potential Cp1 = 1.1%, at 910 °C at different carburization times of 2, 4 and 6 h. The results obtained show that XC20 steel(non-carburized) has a ferrite-pearlitic structure with a hardness and a Young’s modulus of the order of (150 HV, 26 KN/mm2 ). After carburization, the structure of the carburized layer is transformed in martensite (Fe γ)in which cementite (Fe3C)is imbricated. The depth of the carburized layer and the amount of carbon on the surface gradually increase with increasing carburization time. In addition, the carburized XC20 steel becomes hard and brittle where the hardness and Young’s modulus have been increased for a high holding time until reaching maximum values(845 HV, 48 KN mm−2 ) after 6 h of carburization . However, the toughness of XC20 steel has been reduced from 163 to 40 J cm−2 .
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    Thermal treatment effect on structural and mechanical properties of Cr–C coatings
    (Transactions of the IMF, 2018-03-04) Fellah Mamoune; Aissani Linda; Zairi. A; Abdulsamad. M; Nouveau Corinne; Touhami .M.Z; Djebaili Hamid
    In the present study, the effect of thermal treatment on the mechanical and structural properties of chromium carbide coatings with different thicknesses is evaluated. The coatings were deposited by cathodic magnetron sputtering on XC100 steel substrates. Samples were annealed in vacuum, at different temperatures ranging from 700 to 1000°C for 1 h, resulting in the formation of chromium carbides. X-ray diffraction (XRD), microanalysis X/energy-dispersive X-ray spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy analysis were used to characterise the samples. Mechanical properties were evaluated by nano-indentation tests and the residual stress was calculated with the Stoney formula. The XRD analysis suggests the formation of the Cr7C3, Cr23C6 carbides at 900°C. For thin films, they transformed totally to ternary (Cr, Fe)7C3 carbides and their partial transformation has been observed in the case of thick films at 1000°C, without the formation of Cr3C2 . The EDS and XPS showed the diffusion mechanism between the chromium film and the steel substrate for the Cr, Fe, C, O elements during the annealing treatment. The increase of chromium film thickness from 0.5 to 2.64 µm, contributed to the significant enhancement of mechanical properties such as hardness (H) (from 12 to 26.3 GPa) and Young’s Modulus (E) (from 250 to 330 GPa), respectively.