Tribological study of a bronze obtained by Sintering proceeds

Friction is a widely observed phenomenon requiring scientific capacity in the  tribological behavior of materials. Reliability specialists use language borrowed from the doctors, so they talk about teething, durations of life and death, it is true that the machines as living beings, are born, wear, get tired, suffer defaults and eventually die; That is to say, are reformed, but the comparison stops, because the machines have no nervous system or bloodstream, do not think and feel no pain. Factors that may affect the life, or the factors that affect wear are very numerous: surface characteristics, operating conditions of the lubricant, the atmosphere, and finally the time. In this work we present the effect of speed and load on the tribological characteristics of a Cu 8% Sn bronze pressure sintered self-lubricating mode for two lubricants with different viscosities.Keywords: sintering; powder metallurgy; tribology; lubrication; copper alloy

LES ELECTRONS SECONDAIRES DANS LE PROCESSUS AUGER A LA SURFACE DE L’ALLIAGE Cu-Be

A chaque analyse d’une surface par spectroscopie Auger, il est observé au début du spectre, entre 0 et quelques dizainesd’électrons volts suivant la nature de la surface, un pic d’électrons secondaires très intense par rapport aux pics Auger. Dans cetravail, cette partie du spectre Auger est particulièrement étudiée. La courbe de l’évolution des électrons secondaires vrais aété étudiée et comparée à la littérature. Les surfaces de l’alliage Cu-Be avant et après oxydation à l’oxygène ont étécaractérisées. L’excitation des plasmons de l’alliage, dans le cas de surfaces métallique et oxydé, sont comparées. L’effet dutravail d’extraction sur la forme de la courbe est montré

Modeling of submicronic TMOS

We have developed a model of TMOS submicronic with ultra thin oxide layers as small as 4,5-nm in order to study MOSFET's output characteristics and its associated characterization facility for advanced integrated-circuit design are described. This model makes use of the SPICE3F4 simulator and takes in consideration the majority of the physical effects describing the device's real behavior. The validation of our model has provided us with results on the drain current I$_{\rm DS}$ versus drain voltage V$_{\rm DS}$. Our analysis and conclusions should be of interest to all who work with VLSI circuit technology

Élaboration d'un bronze Cu-8%Sn fritté sous pression et l'étude de son aptitude à l'absorption

L'introduction des píeces miniatures dans le domaine de l'informatique et la microélectronique nécessite une grande précision et un environnement propre. D'autre part, la conservation d'énergie exige des pièces légères et une bonne longévité. Pour résoudre ces problèmes, des pièces autolubrifiées ont été proposées. En effet, plusieurs disciplines peuvent s'ingérer pour élaborer ces pièces : la métallurgie des poudres pour produire des pièces poreuses, la tribologie pour caractériser la pièce en fonctionnement et la mécanique des fluides pour évaluer le comportement échantillon -lubrifiant.
Dans ce présent travail, nous présentons l'évolution de la densité des échantillons élaborés en fonction de : la température d'élaboration, la pression de compactage, et le temps de maintien et l'évolution de l'absorption des lubrifiants par un alliage Cu-8% Sn fritté sous pression. Les lubrifiants choisis sont l'eau et une huile de machine à usage domestique et leur aptitude à l'autolubrification

Study of bronze porous alloy Cu-Sn worked out by metallugy of the powders

Porous bronzes take popularity in various fields of technology. Their development is based on the metallurgy of powders. The samples, in the present study, are worked out by pressure sintering pressure. We used various techniques of characterization: density, hardness, optical and electronic microscopy and diffraction of x-rays. We showed that in the temperature and pressure range or field swept the density believes linearly with these two parameters. The secondary phase was identified. By microscopy, we proved that the structure is not homogeneous. © 2011 Published by Elsevier B.V.SCOPUS: cp.pinfo:eu-repo/semantics/publishe

A new inhibitor for steel rebar corrosion in concrete: Electrochemical and theoretical studies

An original Schiff base 4-hydroxy-3-[1-(3-hydroxy-naphthalen-2-ylimino)-ethyl]-6-methyl-pyran-2-one (L1) is synthesized using the condensation method and characterized by X-ray diffraction spectroscopy (XRD). The compound obtained is a mono-crystal. The study of its inhibitory efficiency with respect to the corrosion of mild steel in reinforced concrete was realized using the potentiodynamic polarization and impedance spectroscopy (EIS) as electrochemical methods. The inhibition power of this Schiff base against the corrosion of mild steel in concrete is studied in the aggressive medium 0.5M NaCl as a function of the concentration of the inhibitor, immersion time and temperature. High inhibition power 90% is determined for the low concentration 10-6M at t=28 days and T= 30°C. This inhibition increases as a function of temperature. The thermodynamic study was used to identify the mechanism of inhibitory action of L1. The inhibiting power (EI%) and the apparent activation energy (Ea) have been calculated at different concentrations of L1. The values of ?Gads, Ea, ?Ha, and ?Sa showed that L1 is a good inhibitor of corrosion of the rebar in concrete in an environment of 0.5M NaCl. The inhibitor studied follows a chemisorption process. The adsorption behavior of this product obeys to Langmuir isotherm. The electrochemical results were confirmed with scanning electron microscopy (SEM). The quantum chemical parameters determined by theoretical calculations were used to elucidate the relationship between inhibiting effect of L1 and its molecular structure. © 2018 Published by ESG.Ministry of Higher Education and Scientific ResearchACKNOWLEDGEMENTS The authors gratefully acknowledge the financial support from the Algerian Ministry of Higher Education and Scientific Research. The authors would like to thank Professors Jean Paul Guisselbrecht from Laboratoire d’Electrochimie et de Chimie Physique du Corps Solide ULP Strasbourg France and Professors Mehmet Erbil and Tunç Tüken from Faculty of Science and Letters Chemistry Department Çukurova University Turkey for helpful