Sciences des matériaux

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Etude de l’influence du traitement thermique sur les propriétés mécaniques et électrochimiques d’un rechargement E-309L / 316L-17 sur l’acier 25CrMo4

Mémoire de Master

The main concerns of industrialists having a relationship with the field of oil drilling is wear and corrosion a set of phenomena that act alone or in combination. We propose through this work in addition to the fact of making bi-materials by the hard reloading process to the MMA coated electrode (Manuel Métal arc), using the electrode E309L-17 in the first pass and 316L-17 in finish on low alloy chromium nickel 25CrMo4 steel, This type of steel is used during maintenance on borehole head preventers. In this welding configuration, see quality on the weld by discussing the effect of the chosen parameters on the cohesion at the substrate-input metal and the optimization of the welding process. Three essential steps to be considered in this study: the production of bi-materials by MMA reloading, microstructural, mechanical characterization of compounds and the electrochemical study in NaCl has 3.5% Voir les détails

Mots clés : 25CrMo4, Interface, reloading, corrosion, tribology, heat treatmen

Étude de l’influence du traitement thermique sur les propriétés mécanique du rechargement ENiCrMo-3 sur l’acier 25CrMo4

A. LALOUI, A. ANIK  (2022)
Mémoire de Master

L’usure est la préoccupation des industriels ayant une relation avec le domaine du forage pétrolier, un ensemble de phénomènes faisant intervenir une détérioration progressive par frottement, érosion qui agissent seuls ou en combinaison. Nous nous proposons, à travers ce travail de réaliser un bi-matériaux par le procédé de rechargement dur, à l’électrode enrobé MMA (Manuel Métal arc), sur l’acier faiblement allié au chrome-nickel 25CrMo4, en utilisant l’électrode ENiCrMo-3. Ce type d’acier est utilisé lors de la maintenance sur les obturateurs de tête de puits de forage. Dans cette configuration de rechargement, voir la qualité du rechargement en discutant l’effet des paramètre choisis sur la cohésion à l’interface substrat-métal d’apport utilisant la technique de corrélation d’image et voir l’effet du traitement thermique par l’approche tribologique sur la partie supérieure du rechargement. Trois étapes essentielles sont à envisager dans cette étude : La réalisation par rechargement MMA, la caractérisation microstructurale et mécanique du composé. Voir les détails

Mots clés : 25CrMo4, Interface, MMA, rechargement, corrélation d’image, fatigue.

Synthesis, Characterization, and Photocatalytic Activity ofBa-Doped BiFeO3 Thin Films.

KHIAT Abdelmadjid, Felicia Gheorghiu Boughelout Abderrahmane.  (2022)

Abstract: In the present paper, Bi1-xBaxFeO3 (BBFO) thin films (where x = 0, 0.02 and 0.05) wereprepared by a combined sol-gel and spin-coating method. The influence of Ba substitutions on thestructural, microstructural, optical properties, and photocatalytic activity of BiFeO3 thin films hasbeen studied. X-ray diffraction pattern correlated with FTIR analysis results confirms that all thefilms have a perovskite structure of rhombohedral symmetry with an R3m space group. Atomicforce microscopy (AFM) and scanning electron microscopy (SEM) were used to investigate thesurface morphology and reveals microstructural modifications with the increase in Ba concentration.The optical properties show that the band gap is narrowed after doping with Ba ions and decreasesgradually with the increase of doping content. The photocatalytic investigations of depositedfilms revealed that Ba doping of BFO material leads to the enhancement of photocatalytic response.The present data demonstrates that Bi1-xBaxFeO3 (BBFO) thin films can be used in photocatalyticapplications. Voir les détails

Mots clés : perovskites; films; optical properties; doped BaTiO3; photocatalytic activity

Synthesis and characterization of hydroxyapatite powder derived of eggshell by precipitation method

Samira TLILI, Saida Bouyegh, kotbia LABIOD, Noura Traiaia, Mohamed Hassani, Bilal Ariche  (2022)

Hydroxyapatite is the inorganic material with formula Ca10(PO4)6(OH)2. It is one of bioceramic was used for one repairs, fixing defects of filing voids in biomedical fields. The use of chicken eggshell is one of the natural sources to obtain the calcium phosphate compounds. The main objective of this study is to synthesize the hydroxyapatite by precipitation method from eggshell. The raw eggshell was calcined at 850°C for 2 hours following by grinding for 16 hours. The HA powder was synthesized by wet chemical method, using eggshells and phosphoric acid (H3PO4). X-ray diffraction spectroscopy (XRD, Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR) were used to characterize the morphology, composition and distribution of the particles. The Thermos gravimetric analysis (TGA-DTA) was also carried out to evaluate the stability of the synthesized HA powder. The particle-size distribution (PSD) of the powder was determined by the laser scattering particle size distribution analyzer. The results showed that the sintered at 1000°C of HA powder resembles the feature of pure and single apatite phase having favorable Ca/P ratio. Voir les détails

Mots clés : hydroxyapatite, Bioceramics, synthesis, Eggshell, Precipitation.

A systematic DFT study of (Ti3/2RE1/2)AlC alloys: A new database foradjustable mechanical and electronic properties

C. Meftah, N. Iles, L. Rabahi, M. Gallouze, H.I. Feraoun, M. Drir  (2022)

In this study, ab initio calculations based on Pseudo-Potential Density Functional Theory (PP-DFT) method arecarried out in order to highlight the partial substitution effect of Rare Earth (RE) elements in the well-known 211-MAX phase of Ti2AlC. The considered elements are Y, Sc and RE = La, Ce, Pr, Nd, Sm, Eu, Gd leading to (Ti3/2RE1/2)AlC alloys. According to the obtained results, the (Ti3/2RE1/2)AlC alloys are significantly less compressibleunder uniaxial stress along x and z axes. They exhibit high resistance to shearing along <001> direction. Inaddition, the calculated heat capacity for (Ti3/2RE1/2)AlC alloys increases with respect to the temperature, amaximum is found in the temperature range 200–300 K. Localized states occur in (Ti3/2RE1/2)AlC alloys due tothe f states filling of the rare earth elements. The magnetic moment of (Ti3/2RE1/2)AlC compounds increasesaccording to 4f n (n=2 for Ce to n=7 for Gd) filling. Our findings provide a theoretical database for new tunableproperties of (Ti3/2RE1/2)AlC alloys. Voir les détails

Mots clés : DFT, Rare earth elements, (Ti3/2Re1/2)AlC, mechanical properties, Localized States, Magnetic moment

Preparation and characteristics of synthesized hydroxyapatite from bovine bones and by co-precipitation method

Saida Bouyegh, Samira TLILI, kotbia LABIOD, Mohamed Hassani, Mohamed Grimet, Oussama Bensalem  (2022)

Hydroxyapatite (HA, (Ca10(PO4)6(OH)2) is a widely studied bioceramic due to its biocompatibility, bioactivity, and chemical similarity to the mineral component of bone. Generally, hydroxyapatite can be made from several natural and synthetic sources. The objective of this study is to prepare hydroxyapatite powders from different precursors (natural or chemical). Hydroxyapatite was synthetized by co-precipitation method, the chemical precursors of which are [Ca(NO3)2.4H2O, (NH4)2HPO4] and the natural source was bovine bone. Bovine hydroxyapatite (BHA) was extracted from the bovine bone bio-waste via thermal method and milling process. Synthesized HA (SHA) was prepared by co-precipitation method with the pH 10.0 of mother liquor. The prepared powders were characterized using various analytical techniques such as XRD, FTIR spectroscopy, thermogravimetry (TG), and scanning electron microscope (SEM). These techniques provide information about the structural, chemical, morphological and physicochemical of each of the prepared powders. The use of co-precipitation method produced a low crystallinity of HA while the thermal method increased crystallinity. On the other hand, the results showed that the Ca / P ratio of synthetic hydroxyapatite (SHA) as well as that of bovine bone source (BHA) was also stoichiometric. Voir les détails

Mots clés : hydroxyapatite, Bovine bone, synthesis, co-precipitation, thermal decomposition.

Tribocorrosion Dependence on Porosity of TiNi Alloysin Phosphate‑Buffered Saline Solution

KAHLOUL Latifa, MEDDAH Soumaya, Nasser Eddine BELIARDOUH, Alex Montagne, Mohamed Bououdina, Said Boudebane  (2022)

Degradations of implants during their service life lead to rejection because of corrosion and wear-related problems, i.e., toxicions and wear particles released into the human body. In this case, tribocorrosion tests are appropriate ways to investigate thesynergistic effect of the corrosion and wear phenomena, on the material implant in simulated body fluids. This study aims toanalyze the bio-tribology as well as the tribocorrosion performances of porous TiNi alloys, fabricated from elemental powdermixture (Ti, Ni) by powder metallurgy. The effect of the level in porosity, resulting from four (04) different cold pressing, wasinvestigated against alumina ball in phosphate-buffered saline solution (PBS) at 37 °C. SEM/EDS microstructural analysesrevealed the presence of various phases with TiNi as the predominant phase. Obtained results showed that the lowest frictioncoefficient was recorded for the sample with 33% in porosity rate when sliding against an alumina ball in dry conditions. Ahigh tribocorrosion resistance for all the studied TiNi compositions was also observed. Based on the corrosion parametersand the wear rate, the composition with the highest porosity exhibited the optimum performance. Voir les détails

Mots clés : TiNi alloys, Biotribolgy, Tribocorrosion, Porosity

A0 Lamb Mode Tracking to Monitor Crack Evolution in Thin Aluminum Plates Using Acoustic Emission Sensors

El yamine DRIS, Mourad Bentahar, Redouane DRAI, Abderrahim El Mahi  (2022)

This paper presents a real time monitoring methodology to identify the location of acoustic emission (AE) sources generated by microcracks created within an aluminum plate when submitted to a tensile load. The real time detection of the AE hits was performed by means of a network of piezoelectric sensors distributed on the surface of the plate. The proposed localization approach is based on the combination of the time-frequency analysis of the detected AE hits with an extended Kalman filter (EKF). The spatial coordinates of the AE sources were determined by solving a set of nonlinear equations, where the extended Kalman filter is based on an iterative calculation. By considering the statistics related to the estimation of the coordinates’ errors, results show that the proposed method is in agreement with the experimental observations related to the propagation of the crack when the aluminum plate is under load. Voir les détails

Mots clés : Acoustic Emission (AE), AE events localization, Continuous Wavelet Transform (CWT), crack propagation, Extended Kalman Filter (EKF), Lamb waves, tensile test

Argon flow rate effects on the optical waveguide properties of DC sputtered TiO2 thin films

Hacene Serrar, Fatima-Zohra Mecibah, Ines Kribes, Yassine Bouachiba, Abdelouadoud Mammeri, Abderrahmane BOUABELLOU, Mohamed Retima, Abderrahmane BOUGHELOUT, Adel TAABOUCHE, Redha Aouati  (2022)

TiO2 thin films were successfully prepared by DC sputtering using pure titanium target in mixed gases (Argon, Oxygen) plasma on glass substrates. The films were deposited at a constant substrate temperature (350 °C) with different Argon flow rate values (15, 30, 45, and 60 sccm). Raman spectroscopy analysis shows that all films crystallized in the Anatase phase. The crystallinity was found to improve with increasing Argon flow rate up to 45 sccm and then deteriorate sharply at 60 sccm. The crystallite size varied between 9.1 and 9.7 nm. Atomic force microscopy (AFM) revealed that the roughness fluctuated between 1.30 and 6.01 nm with an overall increase. The grain shape went from sharp needles like shape to dome like shape with an enlargement in their size by up to 60 nm. The UV–Vis spectrophotometer displayed that the films were highly transparent. The optical band gap ranged from 3.65 to 3.49 eV. Prism coupler analysis exhibited single guided modes in both transverse electric and transverse magnetic polarizations for the sample prepared at 15 sccm Argon flow rate and bi-guided modes in both polarizations for the rest of the samples. Both ordinary and extraordinary refractive indices decreased over Argon flow by 9.912% and 6.441% respectively. The thickness, porosity as well as the birefringence where found to increase by 155 nm, 16.16% and 0.0832 respectively as Argon flow rate went from 15 to 60 sccm. Voir les détails

Mots clés : Ar flow rate, DC sputtering, Prism coupler, Refractive indices, TiO2, waveguides

Effects of Erbium Incorporation on Structural, Surface Morphology, and Degradation of Methylene Blue Dye of Magnesium Oxide Nanoparticles

Imene Ameur, Ahmed reda Khantoul, Boubekeur Boudine, Valérie Brien, David Horwat, Miloud Sebais, Ouahiba Halimi  (2022)

This paper reports the chemical synthesis of MgO and Er-doped MgO nanoparticles (NPs) by the sol–gel method. Their microstructural, optical characterization and the evaluation of their photocatalytic activity are presented. The synthesized NPs were characterized by means of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Environmental Scanning Electron Microscopy (ESEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDX), UV–Visible and Photoluminescence (PL) spectroscopy. The effective synthesis of cubic MgO compound is attested by XRD, FTIR and electron diffraction in TEM. Er2O3 cubic secondary phase is found in the 2 and 3 wt% Er-doped MgO samples. The average size of the roundish cuboid-shaped crystallites decreases from 50 to 32 nm upon the incorporation of the rare earth element (TEM, XRD). Concomitantly, the size of flakes in which the NPs do agglomerate follows the same trend (ESEM). UV–Visible results show that the calculated band-gap energy of the NPs was in the 5.23 to 5.35 eV range. PL analysis showed that all samples have visible emissions owing to the formation of defects in the MgO band-gap. The photocatalytic activity against methylene blue dye was evaluated under UV light irradiation. The photocatalytic results showed an improvement in degradation efficiency with the addition of erbium in samples, with a maximal MB dye removal for the 3 wt% Er-doped MgO sample after 90 min irradiation. The performance is ascribed to a higher separation of the photo-generated (electron–hole) and larger surface area. Voir les détails

Mots clés : Erbium, methylene blue, MgO, Photocatalytic activity, X-ray diffraction