Publications Scientifiques

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Author: search.filters.author.Aknouche, HamidHas files: No

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    Bias voltage effect on magnetron sputtered titanium aluminum nitride TiAlN thin films properties
    (EDP Sciences, 2019) Ait-Djafer, Amina Zouina; Saoula, Nadia; Wamwangi, Daniel; Madaoui, Noureddine; Aknouche, Hamid
    In this study, a negative substrate bias voltage is used to tune the structural, morphological, mechanical and electrochemical properties of TiAlN coatings fundamental for protective coating applications. TiAlN thin films have been deposited on glass, (001)Si and stainless steel substrates by RF magnetron sputtering at a power density of 4.41 W/cm2. The deposition rate was determined from X-ray reflectivity measurements to 7.00 ± 0.05 nm/min. TiAlN films used in this work were deposited for 60 min to yield a film thickness of 420 nm. Structural analysis has shown that TiAlN coating forms a cubic (fcc) phase with orientations in (111), (200), (220) and (222) planes. The deposited coatings present maximum hardness (H = 37.9 GPa) at −75 V. The dependence of hardness and Young's modulus and corrosion resistance on microstructure has been established. Electrochemical studies by potentiodynamic polarization in aggressive environment (3.5 wt.% NaCl) have revealed that stainless steel substrate with TiAlN coating exhibits excellent corrosion resistance
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    Parametric study of the mechanical properties of nanocrystalline TiN/CrN multilayer coatings with a special focus on the effect of coating thickness and substrate roughness
    (Elsevier, 2021) Atmani, Taous Doria; Gaceb, M.; Aknouche, Hamid; Nouveau, C.; Bouamrene, M.S.
    In a plot to improve the performance of steel mechanical parts subject to aggressive friction solicitations, three batches of deposits of TiN and CrN layers on steel substrates with two different roughnesses have been obtained using reactive DC magnetron sputtering. The present study was conducted to determine the effect of varying TiN/CrN multilayer coatings thickness (varying modulated period Λ and interlayer thickness), on their mechanical and tribological properties. The morphological and the structural properties were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The nanoindentation measurements displayed improvement in hardness (> 40 GPa) and Young's modulus (> 600 GPa) for the coating with Λ ≅ 12 nm (TiN Λ/2 ≅ 7.5 nm + CrN Λ/2 ≅ 4.5 nm) thickness and the higher number (300) of interfaces, deposited on the rougher substrate. Its low coating damage under the scratch test, associated with its estimated adhesion work (Wad), indicated a good cohesive/adhesive strength and improved structural and mechanical properties