Naïma Boutarek

University of Sciences and Technology Houari Boumediene | usthb · Department of Materials Sciences

The current study presents for the first time the preparation of a NiAl (68 wt.% Ni) intermetallic compound through the induction heating technique as a cathode for alkaline water electrolysis. The high-purity target was confirmed by X-ray diffraction and scanning electron microscopy combined with energy dispersive X-ray analysis. The chemical acti...

This work is devoted to the elaboration of Ni68%Al32% wt. (NiAl) intermetallic compound highly electro-active and cost-effective electrode materials using an induction furnace utilized as cathodes in alkaline water reduction into hydrogen. The XRD analysis showed the formation of the NiAl phase with an average crystallite size of 44.13 nm. The SEM/...

This work is devoted to the elaboration of Ni68%Al32% wt. (NiAl) intermetallic compound highly electro-active and cost-effective electrode materials using an induction furnace utilized as cathodes in alkaline water reduction into hydrogen. The XRD analysis showed the formation of the NiAl phase with an average crystallite size of 44.13 nm. The SEM/...

Semiconductors as photoelectric catalysis is recognized as a promising strategy for simultaneous face energy crisis and environmental pollution. In this study, amorphous silicon carbide (SiC) thin films were deposited on Si (100) by reactive direct current magnetron sputtering at room temperature of high purity silicon carbide 6H SiC target. By DRX...

The present work aims to determine the mechanical, morphological and chemical properties of silicon nitride coating applied on silica crucible substrate used for silicon production for photovoltaic application in order to understand and thereby improve the quality of the coated silica crucible system used in this industry. To evaluate the silicon n...

Solar energy is a clean renewable energy source. During the electricity production, photovoltaic systems do not generate any waste or toxic emissions. However, if this industry is to truly present a sustainable solution it must account for the photovoltaic solar panels’ end-of-life phase. According to the already installed PV panels and its predict...

The present research is related to characterize Tebessa Algerian silica sand with several techniques, to provide briquetting process and to exploit it in the silicon metal production project for photovoltaic application. Acid leaching was used to remove the impurities especially iron and aluminium found in the silica sand. Eight experiments were ca...

In this work, three catalysts (nickel, cobalt, copper) are electrochemically deposited on stainless steel substrates AISI 430 and their performances as cathodes in the hydrogen evolution reaction (HER) are investigated. The electrodes, characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), have been the subject of a study...

Dune sand, from Biskra, Algeria which is in the Great Algerian huge desert attracts tourists from all over the world. Dune sand composes around 80% of the total area of the desert. To date only a few studies have been conducted on this sand. The purpose of the present study is to shed light on the textural and physico-chemical characteristics of th...

Le quartz est la matière première principale pour la production du silicium. De nos jours, les industriels ont retenu le quartz en morceau pour la production du silicium et cela pour éviter la production des fines qui affectent négativement le fonctionnement du four et le procédé de carbo-réduction. Malheureusement, obtenir du quartz pur devient de...

This study aims to consolidate the surface of gray cast iron with aluminum deposition by developing a method that combines the preparation and surface treatment in a single operation. The effect of the wall thickness of the castings on the microstructure of the formed layers was studied, and two thicknesses, 8 mm and 25 mm, were studied. The format...

The purpose of this study was to determine the impact of niobium addition as an inoculation element on the microstructure and electrochemical properties of EN-FGL250 gray cast iron. Niobium additions are in a powder form and have a 0.5 mm particle size at dfferent proportions of 1wt.% and 3wt.%. The addition was done during casting of the metal in...

Many of today's advanced materials depend on quartz as a raw material. Quartz usually contains abundant inclusions, both solid and liquid, and due to the number of these inclusions and their small size, complete separation is most difficult. Typical properties of raw quartz that must be characterized are: Size and Chemical composition of inclusions...

Composite ZrO2-NiO powders synthesised, via the oxidation of Ni40-Zr60 alloy, and ball milled to sizes below 90 nm were spark plasma sintered. The isotherm levels, above the monoclinic–tetragonal (m–t) transition temperature in ZrO2 (1170°C), were in the range 1200 and 1300°C. Microstructures with grain sizes between 100 and 900 nm were achieved. T...

The effect of the oxidation temperature of sintered UO2 pellets on the powder properties of U3O8 was studied in the temperature range 250–900 °C in air. The U3O8 was obtained at 450 °C after 180 min and its particle size and surface area are respectively, 35 µm and 0.7 m2/g. The reduction of the U3O8 powder resulted in UO2 after 30 min with a surfa...

Raw materials are essential for the functioning of modern societies, and access to these raw materials is vital to the world economy. Sustainable development, both globally level, raises important new challenges associated with access and efficient use of raw materials. High purity quartz, is consider as a critical raw material and it is a rare com...

This study is concerned with the research and development in the field of materials science, leading to the industrial applications especially for the development of materials by moulding process. The purpose of this study was to determine the influence of vanadium on microstructural, mechanical and electrochemical properties of gray cast iron with...

The work was devoted to study the recycling process of the unirradiated defective uranium dioxide pellets stored during 10 years. The effect of the temperature on the kinetics of the oxidation and reduction of dioxide uranium was investigated, respectively, in the range 250 °C–600°C and 300 °C–800 °C. For the oxidation process, the kinetics is low...

L'objectif principal de ce travail est d'étudier et l'influence de traitements de surface de titanisation et nitruration sur le comportement à la corrosion électrochimique de matériaux métalliques largement utilisés comme biomatériaux (système acier inoxydable austénitique 304/ titane). Parmi les résultats obtenus, on distingue la formation d’une c...

The present work is a continuation of research on alloys based on iron, with the aim to understanding the solidification behaviour of Fe-V-Nb alloys. Solidification sequences are proposed in relation to the observed microstructures for Fe-V-Nb synthesis alloys. Fe-V-Nb binary alloys with different concentrations are arc melted and characterized sys...

Parmi les alliages métalliques, les aciers où le fer est l’élément de base, constituent une classe exceptionnelle par la diversité des nuances proposées et leur large champ d’application aussi bien dans les domaines industriels les plus divers comme les industries mécaniques, chimiques, automobile et aéronautique, que dans le domaine de la recherch...

The present work is a continuation of research on alloys based on iron, with the aim to understanding the solidification behaviour of Fe-Cr-Nb alloys. Ternary Fe-Cr-Nb alloys with different concentrations are arc melted and systematically characterized by means of; differential thermal analysis, optical and scanning electron microscopy coupled to a...

This study focuses on the characterization and examination of the fracture mechanisms acting simultaneously on the fractured surface of a nickel-based Inconel 713 superalloy gas turbine blade. This objective is reached using a variety of experimental approaches to determine the material's properties (chemical composition, morphology and crystalline...

CO2 laser beam welding with a continuous wave is a high energy density and low heat input process. The result of this is a small heat-affected zone (HAZ), which cools very rapidly with very little distortion. Welding is a necessary process during fabricating fuel rods and fuel assemblies with Zircaloy-4 cladding, and electron beam welding is one of...

For a lot of applications in the mechanical industry, both attractive and mechanical properties of materials and wear resistance are required. Usually such a combination is achieved only by performing surface treatments. The aim of this investigation is the consolidation of 12% Mn steel surface by treatment of impacts. We show by optical and scanni...

This study presents a new configuration for the growth of 3C-SiC polycristals crystals and 6H-SiC homoepitaxial layers. The apparatus consists of a modified Czochralski puller, equipped with a cold crucible able to work under controlled atmosphere. Without any contact between the liquid and the crucible, only the liquid is heated and the whole liqu...

Fe-V binary alloys with different concentrations of vanadium (4-55 at. %) are arc melted and characterized systematically by means of differential thermal analysis, optical and scanning electron microscopy coupled to an energy dispersive X-Ray microprobe analysis, quantitative XRF spectrometry and X-Ray diffraction. In the present paper, solidifica...

Major thermo-physical properties data are of fundamental importance to accurate and reliable design of melting and casting processes. In this paper, we show that we can control the germination process using thermodynamics data. These data must be known for the entire period of time and temperature range of interest in any given condition. In additi...

The present work is a continuation of research on alloys based on iron, aiming at understanding the solidification behaviour of Fe-Cr-Nb alloys. Ternary Fe-Cr-Nb alloys with different concentrations were arc-melted and systematically characterized by means of; differential thermal analysis, optical and scanning electron microscopy coupled to an ene...

Welding is a joining procedure that offers some benefits over mechanical fasteners such as weight reduction and absence of notches induced by machining operations. CO(2) laser beam welding with a continuous wave is a high energy density and low heat input process. The result of this is a small heat-affected zone (HAZ), which cools very rapidly with...

This study focuses on the characterization and examination of the fracture mechanisms acting simultaneously on the fractured surface of a nickel-based Inconel 713 superalloy gas turbine blade. This objective is reached using a variety of experimental approaches to determine the material's properties (chemical composition, morphology and crystalline...

The growth of SiC crystals or epilayers from the liquid phase has already been reported for many years. Even if the resulting material can be of very high structural quality and the possibility to close micropipes was demonstrated, handling the liquid phase still is a challenge. Moreover, it is highly difficult to stabilize the C dissolution front...

Fe – V binary alloys with different vanadium concentrations (4 to 55 at.%) are arc melted and systematically characterized by means of; (1) differential thermal analysis, (2) optical and scanning electron microscopy coupled to an energy dispersive X-ray microprobe analysis, (3) quantitative X-ray fluorescence spectrometry, and (4) X-ray diffraction...

The growth of 3C-SiC polycrystal and 6H-SiC homoepitaxial layers from Metal-Si alloys is carried out as function of temperature and propane partial pressure. Based on the vapourliquid-solid mechanism, we present a new configuration for the growth of SiC which could allow first to simplify the liquid handling at high temperature and second to precis...

The PrGe1.6 compound shows two coexistent crystallographic structures, which are ordered and disordered variants of the ThSi2 structure, the ordered phase resulting from the ordering of Ge vacancies. Comparison is made with CeGe1.6 and Ce and Pr silicides, which exhibit the same type of phase separation.

Polymer-based composites being composed of a polymer in which specific additives are imbedded, derive most of their physical properties from such additives. In this presentation, it is shown how some of the properties of such plastics may be effected by excimer laser irradiation via processing the imbedded additives without altering the polymeric b...

The series of disilicides and digermanides of praseodyme with the composition PrX2−x (XSi or Ge) were investigated using X-ray diffraction, metallographic studies, electrical resistivity and magnetic measurements. The original result presented here is evidence of new phases that can be identified as ordered and disordered variants of the ThSi2 str...

The phase diagram of the CeGe2−x compounds (0.1<×<0.6) is redefined. The occurrence of two tetragonal phases in equilibrium in a single crystal of CeGe1.54 is observed by optical microscopy. The two phases are identified by X-ray diffraction as ordered and disordered variants of the ThSi2 structure; their magnetic properties are characterized by ne...

Few studies have been up to now devoted to the metallization of Si-Ge alloys and most of them concerns the sequence of phases formation for thin films interactions. In order to obtain a better understanding of these metallization processes, we have determined the thermodynamic equilibrium state by a systematic analysis of the ternary phase diagrams...

Some crystallographic properties of solid solutions of the Ce-Si-Ge system were investigated. A new type of superstructure was observed in the compound CeGe0.66Si0.92, with an alternation of silicon- or germanium-rich planes; this compound undergoes a crystallographic transition at low temperature. Two different tetragonal phases coexist at room te...

The orthorhombic phase of iron silicide, β-FeSi2, is a semiconducting material whose preparation is compatible with silicon processes. Epitaxy on Si has been achieved recently [1]. Its direct gap of 0.85 eV seems to make it suitable for infrared applications as a detector or emitter. Samples studied here have been prepared by several methods, inclu...

Samples of beta-iron silicide were prepared by three different methods : solid phase reaction on silicon (111), on a monocrystaline FeSi substrate, and from the melt. These samples have been characterized by x-ray diffraction and investigated by Infrared and Raman spectroscopies. The infrared and Raman lines are compared with theoretical prediction...