Download or read book tude et d veloppement de nouveaux traitements de surface sur alliage de magn sium Elektron 21 written by Benjamin Mouls and published by . This book was released on 2014 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'objectif général de cette thèse était l'élaboration de films protecteurs, exempts de toutes espèces CMR, par imprégnation de couches de conversion sur un alliage de magnésium, dans l'optique d'en améliorer la résistance à la corrosion. L'alliage étudié était l'Elektron 21 (EV31A), disponible sous forme de deux substrats différents (EL21T6) et (EL21T5), présentant des microstructures différentes. Cette étude avait alors deux objectifs majeurs : - La compréhension et le contrôle des mécanismes mis en jeu lors d'un décapage en milieu d'acide nitrique, afin de parvenir à un procédé répétable d'enlèvement de matière. - L'élaboration en milieu acide d'un film anodique poreux et son imprégnation ultérieure par des nanoparticules grâce à un procédé d'électrophorèse. La première partie de l'étude a permis de définir l'influence de différents paramètres expérimentaux (concentration en acide, température et agitation de la solution) vis-à-vis de la vitesse de décapage en solution d'acide nitrique. Cette partie expérimentale a abouti au choix d'un décapage-standard (Tbain = 25°C, agitation modérée (250rpm), [HNO3] = 1,20 mol/l) permettant d'obtenir un enlèvement matière constant, et ce même après plusieurs utilisations du bain de décapage. Des études thermodynamique et de cinétique chimique ont permis par ailleurs d'établir pour la première fois les valeurs des paramètres cinétiques correspondants (ordre de réaction, constante de vitesse moyenne, énergie d'activation). Concernant l'anodisation poreuse, le choix de l'électrolyte s'est porté sur l'acide phosphorique, utilisé par ailleurs pour les conversions chimiques sur magnésium. L'objectif a été alors de favoriser la composante électrochimique du procédé afin de contrôler au mieux la formation de la couche de conversion. Des mesures de variation de masse ainsi que l'analyse des bains par ICP ont permis de montrer que l'influence de la polarisation est plus importante pour la concentration la plus faible en acide phosphorique (0,01mol/L), cette influence étant d'autant plus marquée lorsque la température du bain est augmentée de 25 à 75°C. Des analyses EDX et DRX ont permis de montrer de plus que le film est en partie amorphe et en partie cristallisé, et est constitué notamment de newberyite (MgHPO4,3H2O). Les observations MEB ont permis de montrer en outre que l'épaisseur des films anodiques est plus importante que celles des films de conversions chimiques élaborés dans les mêmes conditions opératoires. Toutefois, les films anodiques présentaient une grande porosité, due à l'existence de nombreuses microfissures, qu'il était donc nécessaire de combler. Dans cette optique, un procédé d'imprégnation électrophorétique a été mis en œuvre et a finalement permis, par l'étude de l'influence de certains paramètres (tension, durée), de combler avec succès ces fissures avec des nanoparticules de silice. Par contre, l'évaluation, par impédance électrochimique, de la tenue à la corrosion a montré la nécessité ultérieure d'imprégner des particules comportant une fonction inhibitrice de corrosion.
Download or read book Gilded Metals written by Terry Drayman-Weisser and published by . This book was released on 2000 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through this lavishly illustrated volume, readers will discover how various cultures, ranging from ancient societies to more recent Western cultures, created gilded surfaces and how the allure of gold inspired new and ingenious technologies. Among others, practical techniques covered include foil and leaf gilding, depletion and diffusion techniques, fire gilding and electroplating. Conservation issues are also addressed.
Download or read book Nuclear Energy written by Nicholas Tsoulfanidis and published by Springer Science & Business Media. This book was released on 2012-12-12 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear Energy provides an authoritative reference on all aspects of the nuclear industry from fundamental reactor physics calculations to reactor design, nuclear fuel resources, nuclear fuel cycle, radiation detection and protection, and nuclear power economics. Featuring 19 peer-reviewed entries by recognized authorities in the field, this book provides comprehensive, streamlined coverage of fundamentals, current areas of research, and goals for the future. The chapters will appeal to undergraduate and graduate students, researchers, and energy industry experts.
Download or read book Design and Modeling of Mechanical Systems written by Mohamed Haddar and published by Springer Science & Business Media. This book was released on 2013-03-12 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 5th International Congress on Design and Modeling of Mechanical Systems (CMSM) was held in Djerba, Tunisia on March 25-27, 2013 and followed four previous successful editions, which brought together international experts in the fields of design and modeling of mechanical systems, thus contributing to the exchange of information and skills and leading to a considerable progress in research among the participating teams. The fifth edition of the congress (CMSM ́2013), organized by the Unit of Mechanics, Modeling and Manufacturing (U2MP) of the National School of Engineers of Sfax, Tunisia, the Mechanical Engineering Laboratory (MBL) of the National School of Engineers of Monastir, Tunisia and the Mechanics Laboratory of Sousse (LMS) of the National School of Engineers of Sousse, Tunisia, saw a significant increase of the international participation. This edition brought together nearly 300 attendees who exposed their work on the following topics: mechatronics and robotics, dynamics of mechanical systems, fluid structure interaction and vibroacoustics, modeling and analysis of materials and structures, design and manufacturing of mechanical systems. This book is the proceedings of CMSM ́2013 and contains a careful selection of high quality contributions, which were exposed during various sessions of the congress. The original articles presented here provide an overview of recent research advancements accomplished in the field mechanical engineering.
Download or read book Peaceful Uses of Atomic Energy written by United States. Department of State and published by . This book was released on 1955 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reactor Materials written by and published by . This book was released on 1968 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the First International Congress of Radiation Protection written by and published by . This book was released on 1968 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A CONF 15 P written by and published by . This book was released on 1958 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Subcritical Assemblies written by W. Maurice Pritchard and published by . This book was released on 1963 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nondestructive Activation Analysis written by Saadia Amiel and published by Elsevier Science & Technology. This book was released on 1981 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Offshore Power Systems written by Faye H. Horn and published by . This book was released on 1974 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ZnO Thin Films written by Paolo Mele and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) is an n-type semiconductor with versatile applications such as optical devices in ultraviolet region, piezoelectric transducers, transparent electrode for solar cells and gas sensors. This book "ZnO Thin Films: Properties, Performance and Applications" gives a deep insight in the intriguing science of zinc oxide thin films. It is devoted to cover the most recent advances and reviews the state of the art of ZnO thin films applications involving energy harvesting, microelectronics, magnetic devices, photocatalysis, photovoltaics, optics, thermoelectricity, piezoelectricity, electrochemistry, temperature sensing. It serves as a fundamental information source on the techniques and methodologies involved in zinc oxide thin films growth, characterization, post-deposition plasma treatments and device processing. This book will be invaluable to the experts to consolidate their knowledge and provide insight and inspiration to beginners wishing to learn about zinc oxide thin films.
Download or read book Nuclear Techniques for Mineral Exploration and Exploitation written by International Atomic Energy Agency and published by . This book was released on 1971 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Industrial Application of Radioisotopes written by Gábor Földiák and published by . This book was released on 1986 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:
