Browsing by Author "Aknouche, Hamid"

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Applications of CrAlN ternary system in wood machining of medium density fibreboard (MDF)
(2009) Benlatreche, Y.; Nouveau, C.; Marchal, R.; Martins, J-P. F.; Aknouche, Hamid
Nowadays, medium density fibreboard (MDF) composite wood is more and more used in the furniture industry to replace bulk wood such as oak, beech, etc. Indeed, this material presents good mechanical properties, is easy to machine, homogeneous, exists in different dimensions (thickness, etc.), is cheaper than bulk wood and finally can be covered by an adhesive decorative coat. Nevertheless, even if this material is homogeneous, it is abrasive enough to tend to the breakdown of the conventional carbide tools employed during its routing process. That is why it is necessary to improve the wear resistance of these tools. One solution is to protect them with a hard coating. The present study deals with the development of ternary CrAlN hard layers obtained by PVD method on carbide tools employed in second transformation of wood. CrAlN coatings have been optimized and then applied on carbide tools in routing of three types of MDF: standard, waterproof and fireproof. The aim of these wood machining tests was first to define the ability to be machined of the three kinds of MDF and second to compare the effectiveness of CrAlN coatings during the routing tests of these materials
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
Comparison of CrAlN layers obtained with one (CrAl)or two targets (Cr and Al) by magnetron sputtering
(2012) Nouveau, C.; Tlili, B.; Aknouche, Hamid; Benlatreche, Y.; Patel, B.
The aim of this study is to compare the properties of CrAlN coatings obtained by magnetron sputtering with one (CrAl) or two targets (Cr and Al). The influence of parameters such as the target bias voltage, the working pressure, the deposition time and the bias voltage applied on the Cr or Al targets on the properties of the layers was studied. We characterized the films by X-ray Diffraction, Scanning Electron Microscopy, coupled with Energy Dispersive Spectroscopy, nanoindentation and their residual stresses were also determined. The optimal films obtained with both methods are well crystallized, well-adherent to the substrate, and contained similar amounts of Al (20–30 at.%). The optimal coatings synthesized with one target presented properties not as good as those realized with two targets. Nevertheless, films made with one target showed a lower frictional coefficient probably due to composition control. The lack of compositional control with the use of one target limits the optimization process. With two targets, we have greater control over the film composition. This leads to higher hardness, lower stresses, and improved Young's modulus over films produced with a single CrAl target. Additionally, the morphologies are different (columnar with CrAl and dense with Cr and Al). To conclude, it seems more justified to work if possible with two independent targets
Deposition and characterization of titanium aluminum nitridecoatings prepared by RF magnetron sputtering
(Elsevier, 2015) Ait Djafer, Amina Zouina; Saoula, Nadia; Aknouche, Hamid; Guedouar, Bendiba
An ecological water‑based drilling mud (WBM) with low cost: substitution of polymers by wood wastes
(Springer, 2019) Haider, Soumia; Messaoud‑Boureghda, Mohamed‑Zine; Aknouche, Hamid; Akkouche, Ali; Hammadi, Larbi; Safi, Brahim
An ecologically friendly water-based drilling mud (WBM) was designed by using wood wastes (WP: wood powder) in order to substitute the organic polymers which are very expensive and often make the higher cost of the oil well drilling. This present work is dedicated on studying the rheological behavior and main rheological properties of WBM containing the wood powder at different contents and sizes by substitution of usually used polymers. The effect of wood powder on the drilling fluid filtrate was also analyzed. The drilling fluid that was developed has better rheological properties and fluid loss control which are required for a good functioning of oil well drilling. By a total substitution of polymers, the wood powder (300 μm at 850 kg/m3) can be used as a filtrate reducer of mud because the WBM filtrate obtained exhibits a minimum and having requested values for such formation
Effects of Nitrogen Content on the Structural, Mechanical, and Corrosion Properties of ZrN Thin Films Grown on AISI 316L by Radiofrequency Magnetron Sputtering
(Wiley, 2021) Azibi, Mourad; Saoula, Nadia; Madaoui, Noureddine; Aknouche, Hamid
Zirconium nitride films are deposited onto stainless steel AISI 316L and silicon (100) by radio frequency magnetron sputtering at different nitrogen flow ratios [N2 /(Ar+N2 )] varied between 0 and 0.25). Scanning electron microscope, atomic force microscopy, X-ray diffraction (XRD), and Raman are used to investigate the surface morphology and microstructure of the thin films. The mechanical and electrochemical properties of all coatings are evaluated and compared with the uncoated AISI 316L to explore the efficiency of surface modification. The XRD and Raman analysis show that all the films are crystalline. This shows that the increased nitrogen content leads to a transformation from hexagonal 𝜶-Zr phase to cubic c-Zr and then to mixed 𝜶-Zr and face centered cubic c-ZrN phases. The films deposited with nitrogen flow ratio of 0.2 show the highest hardness of 32.2 GPa. Using the potentiodynamic polarization method, the corrosion behavior of the films is studied in Hank’s solution. The comparison between uncoated and coated substrates shows a decrease in corrosion current density for all coated samples.
Étude de l'influence de l'inclinaison des cannelures sur le comportement à l'usure des cylindres broyeurs de blé
(2002) Aknouche, Hamid
Le suivi du comportement des équipements de l'industrie alimentaire, lors de leur exploitation est l'une des préoccupations majeures pour le maintien de la meilleure qualité des produits céréaliers. La perte des performances des mécanismes des machines alimentaires est due dans la plupart des cas à une dégradation importante causée par l'usure. Cette dernière est souvent accélérée par la présence de corps étrangers entre les surfaces en frottement. A cet effet, nos investigations, en milieu industriel, notamment dans la branche alimentaire (semoulerie); relève que la matière première renferme une quantité non négligeable en déchets qu'on qualifie de corps indésirables. Ce travail a pour finalité de répondre à des préoccupations liées à l'exploitation optimale des broyeurs à cylindrées dans les entreprises algériennes de transformation des céréales…
Etude de l’usure des outils de coupe traités dans le domaine de l’usinage du bois
(2009) Aknouche, Hamid
L’évolution des moyens de production dans l’industrie du bois et la concurrence internationale imposent des rentabilités de plus en plus élevées où les nouvelles technologies et matériaux de coupe sont des points clés de la productivité. Dans le contexte industrie bois, chaque machine-outil est associée à un produit donné, dont l’intérêt est de maîtriser les conditions d’usinage dues aux coûts financiers au demeurant très important des machines. Pour des conditions de rendement optimum, il est impératif que les pertes de matière et fréquence de changement d’outils soient minimisées au même titre que les coûts de production. La présente recherche a eu comme objectif principal d'identifier les mécanismes d’usure des outils coupants dans la première et seconde transformation du bois et de préconiser des solutions afin d’augmenter la productivité des outils de coupe, par l’application des revêtements durs. En effet, un revêtement de protection est supposé être stable vis-à-vis de l’environnement chimique et mécanique auquel il est soumis durant son utilisation. Un revêtement dur n’est pas déposé tel quel sur un outil de coupe pour accroître la durée de vie et la résistance à l’abrasion de l’outil, surtout pour des utilisations en usinage à grande vitesse sans lubrification. Ce revêtement s’avérera efficace si sa mise en œuvre inclut une étude préalable du type de revêtement, des moyens pour l’obtenir et des ajustements des paramètres du procédé d’élaboration. De ce fait on a élaboré des revêtements CrAlN, CrSiN et TiAlN, la caractérisation de ces revêtements nous a permis de voire l’influence de l'Al sur la structure ainsi que la stabilité thermique et les propriétés mécaniques et tribologiques des films. Les tests d’usinage des outils revêtus, ont montrés que le revêtement CrSiN a donné des résultats intéressants quant a son aptitude a résister à l’usure et aux chocs qui peuvent être générés par les noeuds. Dans l’opération de défonçage, le film CrN possède l’usure la plus réduite après 1500m de d’usinage du MDF
Improvement of the tribological behavior of TiN/CrN multilayer coatings by modulation wavelength variation
(Elsevier, 2024) Atmani, Taous Doria; Bouamerene, Mohammed-Said; Gaceb, Mohammed; Nouveau, Corinne; Aknouche, Hamid
Hard coatings are widely used in materials engineering as surface coatings to protect mechanical parts subject to friction. For a coating to be functionally successful, it should possess high wear resistance. Experimental work has been performed on TiN/CrN multilayer coatings with various modulated periods, deposited on XC48 steel substrates having two different surface roughnesses using reactive direct current magnetron sputtering. Their Tribological performances were investigated following dry sliding wear tests using a tribometer with ball-on-flat contact configuration. The prevailing wear mechanisms of TiN/CrN coatings are dominated by oxidation of wear debris and counter material transfer. The decreased wear rate was significantly influenced by both the reduction of the period thicknesses and the increase of substrate surface roughness. Nonetheless, varying thickness period in the multilayer and increasing the substrate roughness did not show any significant wear resistance improvement.
Incorporation mode effect of Nano-silica on the rheological and mechanical properties of cementitious pastes and cement mortars
(2018) Saf, Brahim; Aknouche, Hamid; Mechakra, Hamza; Aboutaleb, D.; Bouali, Khaled
Influence de l'angle d'inclinaison des cannelures sur le comportement à l'usure des cylindres broyeurs de blé
(European Journal of Scientific Research, 2008) Aknouche, Hamid; Zerizer, A.; Chemani, B.
Le suivi du comportement des équipements de l’industrie alimentaire, lors de leur exploitation est l’une des préoccupations majeures pour le maintien de la meilleure qualité des produits céréaliers. a perte des performances des mécanismes des machines alimentaires est due dans la plupart des cas à une dégradation importante causée par l’usure. Ce travail a pour finalité de répondre à des préoccupations liées à l’exploitation optimale des broyeurs à cylindres dans les entreprises algériennes de transformation des céréales. Les constructeurs de ces machines utilisent des caractéristiques de cannelures (les angles des cannelures) influençant leur blé local, ce qui déséquilibre leur exploitation dans les semouleries algériennes utilisant d’autres blés. Des relevés en milieu industriel ont été réalisés pour déterminer leurs durées de services. Une étude expérimentale faite sur un banc d’essai réalisé dans notre laboratoire, nous a permis de comparer le comportement à l’usure des cannelures de différentes pentes
The influence of substrate bias voltage on the electrochemical properties of ZrN thin films deposited by radio-frequency magnetron sputtering : biomedical application
(De Gruyter Open Ltd, 2019) Azibi, Mourad; Saoula, Nadia; Aknouche, Hamid
In order to study the influence of the substrate bias on the properties of ZrN thin films deposited by radio-frequency magnetron sputtering for biomedical application. Films of ZrN were grown onto 316L stainless steel substrate using radio-frequency (rf) magnetron sputtering from a pure zirconium target in Ar - N2 gas mixture. The substrate bias voltage was varied from 0 to -100 V, which produces a variation in the structural and electrochemical properties of the obtained films. The deposited films were characterized by X-Rays Diffraction, Atomic Force Microscopy, scanning force microscopy and potentiodynamic polarization
Mesure des efforts de défonçage et de la qualité finale en usinant en différents angles du fil
(2012) Aknouche, Hamid; Goli, G.; Marchal, R.; Sandak, J.
Comparaison entre un bois très commun et usiné en Europe comme le pin Douglas et une essence pas très utilisée comme le pin d'Alep de provenance algérienne. Pour cette comparaison, une nouvelle méthode a été mise au point afin d'évaluer les efforts de coupe et la qualité des surfaces usinées dans le processus du défonçage. Cette méthode a été expérimentée sur du pin d'Alep en coupe orthogonale allant de façon continue de 90°/0° à 90°/90° dans le sens du fil et contrefil afin de juger également de l'aptitude à l'usinage de ce bois par rapport à d'autres essences plus communément usinées. L'outil de coupe est une fraise circulaire comportant deux plaquettes en carbure. Elle est utilisée pour usiner le chant de disques de pin d'Alep prélevés dans une planche, ce qui induit une variation de l'angle du fil continue de 0° à 360°. La mesure des forces de coupe a été faite avec l'emploi d'une table piézoélectrique Kistler 9257A à trois axes montée sur la table d'une défonceuse à commande numérique, couplée à un PC et une carte d'acquisition. Les données sont traitées à l'aide d'un logiciel Dasylab. Parallèlement, des tests de qualité des surfaces usinées avec un outil comportant une arête de coupe neuve sur une moitié et usée artificiellement sur l'autre ont été réalisés par une nouvelle méthode sans contact développée par l'équipe de recherche Cnr/Ivalsa. Les résultats indiquent que les efforts de coupe sont un peu plus grands pour le pin Douglas que pour le pin d'Alep. En revanche, la qualité des surfaces obtenues est bien meilleure pour le pin d'Alep que pour le pin Douglas
Mesure des efforts de défonçage et de la qualité finale en usinant en différents angles du fil : comparaison entre le pin douglas et le pin d'Alep = Measuring cutting effort and the surface quality obtained by routing across different wood grain angles : a comparison between douglas pine and aleppo pine
(2012) Aknouche, Hamid; Goli, Giacomo; Marchal, Rémy; Sandak, Jakub; Zerizer, Abdellatif; Butaud, Jean-Claude
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
Physical and mechanical properties of CrAlN and CrSiN ternary systems for wood machining applications
(2009) Benlatreche, Y.; Nouveau, C.; Aknouche, Hamid; Imhoff, L.; Martin, N.; Gavoille, J.; Rousselot, C.; Yves Rauch, J.; Pilloud, D.
Nowadays, almost all the cutting tools in metal machining are protected with a surface treatment. Nevertheless, this is not the case in woodmachining where no tools are protected, except by thermal treatments, and so they present a previous wear because of the use of steel or carbide materials in milling, sawing, routing, etc. During these processes, the tools are particularly exposed to abrasive and shock wear. To enhance their wear resistance, one solution is to protect them with hard coatings. The present study deals with the development of ternary systems (CrAlN and CrSiN) obtained by two PVD different magnetron sputtering systems [‘A’ (laboratory where CrAlN layers have been obtained) and ‘B’ (laboratory where CrSiN layers have been obtained) in the following text] on carbide WC–Co tools used in second transformation of wood to be compared to the binary CrN one. CrAlN and CrSiN films were deposited with different Al and Si contents, respectively, in order to check the effect of the additive element (Al or Si) on the different properties of the Cr–N system. The different coatings were characterized by SEM and EDS for thickness measurements, morphology and composition analyses, respectively, by nanoindentation for hardness and Young’s modulus measurements and by pin-on-disc to determine their friction coefficient. Routing of medium density fibreboard (MDF) was realized employing untreated or modified carbide WC–Co tools in order to compare their wear resistance. We observed that the Al and the Si addition improved the hardness and the Young’s modulus of the Cr–N system (‘A’: 29 and 410 GPa, respectively, ‘B’: 18 and 280 GPa, respectively). Indeed, the hardness values are 15–36GPa for CrAlN and 15–24 GPa for CrSiN coatings. Besides, the Young’s modulus values are 331–520GPa for CrAlN and 260–320 GPa for CrSiN coatings. The friction coefficient of the CrAlN layers varied between 0.6 and 0.7 and it increased slightly with the Al content. For the CrSiN coatings, the friction coefficient was lower and about 0.4. In both cases, the CrN layers ‘A’ and ‘B’ presented similar friction coefficient than CrAlN and CrSiN, respectively. During the routing of MDF, the CrN ‘A’ coating has a similar wear behaviour than the optimized CrAlN one (5 at.% of Al) while the optimized CrSiN coating (1.2 at.% of Si) showed a better behaviour against wear than the CrN ‘B’ one. The wear resistance of CrAlN- and CrSiN-coated carbide tools decreased when the Al and Si contents increased
Tool wear effect on cutting forces : in routing process of aleppo pine wood
(2009) Aknouche, Hamid; Outahyon, A.; Nouveau, C.; Marchal, R.; Zerizer, A.; Butaud, J.C.
This paper uses the cutting forces in a routing process of Aleppo pine wood to estimate the tool wear effect. The aim is to obtain further information about the tool wear effect by monitoring the variation in the cutting forces. A Kistler 9257A 3 axes Dynamometer was positioned under the workpiece to measure the cutting forces at frequencies up to 10,000 Hz. The experiments were carried out on a CNC routing machine RECORD1 of SCM. A carbide tool was used and the cutting parameters were fixed. The cutting speed was approximately 25 m/s. Dasylab software was used to capture the data. The results show a correlation between the tool wear and the computed angle ( ), between the tangential and cutting forces. In fact, the variation of ( ) is unstable in the running period and stable in the linear wear zone, included in the interval [−1.11◦; −1.10◦]. This study was performed as part of a development program for the Algerian wood industry, hence the selection Aleppo pine wood as the working material
Traceability in wood production
(2013) Zerizer, A.; Nacereddine, H.; Aknouche, Hamid