Download or read book Thermoelectric Properties of Higher Manganese Silicides written by Dao Y Nhi Truong and published by . This book was released on 2015 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work aims to cover a variety of aspects relating to the Higher Manganese Silicide (HMS) system, e.g. composites, substitutions, synthesis methods, and structural evolutions. The composites made of HMS-based compounds and nano-inclusions have been prepared via two different procedures, i.e. (i) solid state reaction, manually mixing, and hot pressing, or (ii) soft ball milling and reactive spark plasma sintering. The later approach has proved its effectiveness in preparing the multi-walled carbon nanotube (MWCNT)/HMS-based material composites mainly containing the HMS phases with a homogeneous distribution of MWCNTs. It was demonstrated that a fine distribution of the nano-inclusions played a crucial role in reducing thermal conductivity through enhancing phonon scattering in HMS-based materials, resulting in an improvement by about 20% for the maximum efficiency for the MWCNT/HMS-based material composite with 1.0 wt.-% MWCNTs. The substitution of molybdenum, tungsten, or silver at the Mn sites, and of germanium or aluminium at the Si sites has been studied for the HMS-based materials. The best thermoelectric efficiency among different Ge contents was achieved for the phase mixture of the non-stoichiometric composition MnSi1.75Ge0.02, which was then chosen to be the base material for further substitutions. No crucial modification of the electrical properties of the base material was observed, but large decreases of lattice thermal conductivity were achieved because of enhanced phonon scattering, with the highest reduction up to 25% for molybdenum substitution. The maximum figure of merit, ZT, value was approximately 0.40 for the material with 2 at.-% molybdenum substitution at the Mn sites. The maximum ZT values ranging from 0.31 to 0.42 have been achieved for various compositions prepared by mechanical alloying, mechanical milling and heat treating in conventional furnace, as well as by solid state reaction, which could possibly be improved by completely eliminating the side products. Subsequently, a simple and effective process was used to synthesize undoped HMS, involving ball milling in n-hexane under soft conditions to obtain homogeneous mixtures of constituting elements, and subsequent spark plasma sintering for a direct solid state reaction. The obtained fine particles after the milling process in n-hexane helped to improve the reaction rate later on, resulting in pure HMS materials. As a consequence, the maximum thermoelectric figure of merit obtained was 0.55 at 850 K, a high value for undoped HMS. Moreover, single crystals of HMS have been prepared using chemical vapor transport with very low yield, but their poor qualities resulted in low resolution in single crystal XRD. HMS-based materials including the ones with different Si/Mn atomic ratios and various dopants, e.g. Ge, Al, Cr, and Mo, have been prepared for the investigation of structural evolution upon heating up from room temperature to high temperature. The average structural formula at room temperature and its temperature dependence were strongly impacted by the phase compositions of the starting materials as well as the nature of dopants. Physical property measurements on the MnSi1.75 compound revealed that a correlation between the thermoelectric properties and the average structural formula of bulk HMS-based materials could be expected.

Download or read book Synthesis and Thermoelectric Properties of Higher Manganese Silicides for Waste Heat Recovery written by Chen, Xi and published by . This book was released on 2015 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric (TE) materials, which can convert temperature gradients directly into electricity and vice versa, have received renewed interest for waste heat recovery and refrigeration applications. Higher manganese silicides (HMS) are promising p-type TE materials due to the abundance of the constituent elements, environmental friendliness, and good chemical stability. The objective of this dissertation is to establish a better understanding of the structure-TE properties relationship of HMS with a complex Nowotny chimney ladder structure. The focus of this work is on the investigations of the phonon dispersion of HMS crystals and the effects of chemical doping and nanostructuring on the TE properties of polycrystalline HMS. HMS crystals have been synthesized by the Bridgeman method for inelastic neutron scattering measurements of the phonon dispersion. In conjunction with density functional theory calculations, the results clearly show the presence of numerous low-lying optical phonon branches, especially an unusually low-energy optical phonon polarization associated with the twisting motions of the Si helical ladders in the Mn chimneys. The obtained phonon dispersion can be used to explain the low and anisotropic thermal conductivity of HMS crystals. (Al,Ge) double doping was found to be effective in modifying the electrical properties of HMS polycrystals. The peak thermoelectric power factor occurs at an optimized hole concentration of 1.8~2.2×1021 cm−3 at room temperature. On the other hand, Re substitution can suppress the lattice thermal conductivity to approach the calculated minimum value corresponding to the amorphous limit. Meanwhile, the thermoelectric power factor does not markedly change at low Re content of x ≤ 0.04 although it drops considerably with increasing Re content. Hence, the peak ZT has been improved to ~0.6 in both systems. The effects of nanostructuring on the TE properties have been studied in the cold-pressed samples and ball-milled samples. The thermal conductivity was reduced remarkably by decreasing the grain size. It is found that the grain size effects are more significant at low temperature. However, it is difficult to reduce the grain size to less than 50 nm without the formation of impurity phases by ball milling. These facts limit the ZT enhancement of the nanostructured HMS at high temperatures in this study.

Download or read book Thermoelectric Energy Conversion written by Ryoji Funahashi and published by Woodhead Publishing. This book was released on 2021-02-05 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric Energy Conversion: Theories and Mechanisms, Materials, Devices, and Applications provides readers with foundational knowledge on key aspects of thermoelectric conversion and reviews future prospects. Sections cover the basic theories and mechanisms of thermoelectric physics, the chemical and physical aspects of classical to brand-new materials, measurement techniques of thermoelectric conversion properties from the materials to modules and current research, including the physics, crystallography and chemistry aspects of processing to produce thermoelectric devices. Finally, the book discusses thermoelectric conversion applications, including cooling, generation, energy harvesting, space, sensor and other emerging areas of applications. Reviews key applications of thermoelectric energy conversion, including cooling, power generation, energy harvesting, and applications for space and sensing Discusses a wide range of materials, including skutterudites, heusler materials, chalcogenides, oxides, low dimensional materials, and organic materials Provides the fundamentals of thermoelectric energy conversion, including the physics, phonon conduction, electronic correlation, magneto-seebeck theories, topological insulators and thermionics

Download or read book Materials Aspect of Thermoelectricity written by Ctirad Uher and published by CRC Press. This book was released on 2016-11-25 with total page 625 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, novel families of materials have been discovered and significant improvements in classical thermoelectric materials have been made. Thermoelectric generators are now being used to harvest industrial heat waste and convert it into electricity. This is being utilized in communal incinerators, large smelters, and cement plants. Leading car and truck companies are developing thermoelectric power generators to collect heat from the exhaust systems of gasoline and diesel engines. Additionally, thermoelectric coolers are being used in a variety of picnic boxes, vessels used to transport transplant organs, and in air-conditioned seats of mid-size cars. Consisting of twenty-one chapters written by top researchers in the field, this book explores the major advancements being made in the material aspects of thermoelectricity and provides a critical assessment in regards to the broadening of application opportunities for thermoelectric energy conversion.

Download or read book Stability of Manganese Silicides of the HMS Type Alloying Effect on Their Electronic Properties written by Ali Allam and published by . This book was released on 2013 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric materials as electric power generators can be used in many fields, such as the conversion of automobile exhausting heat and industrial waste heat, solar photovoltaic-thermoelectric hybrid power generation, or RTG (Radioisotope thermoelectric generator) for deep space exploration. To date, most of the constituent elements of thermoelectric materials are scarce resource and are toxic, resulting in environmental pollution. Silicide materials have shown to exhibit good thermoelectric performances at high temperature without suffering from the aforementioned drawbacks. Among the silicide compounds, silicon-rich silicides MnSix, with x comprised between 1.71 and 1.75, are particularly interesting for their thermoelectric properties. These so-called higher manganese silicides (HMS) exhibit several tetragonal structures that correspond to Mn4Si7, Mn11Si19, Mn15Si26 and Mn27Si47. In this thesis, we examine from an experimental point of view the stability of these compounds. The investigations have been performed on both bulk and thin film materials. Mn4Si7 seems to be the most interesting HMS for thermoelectric applications; hence various synthesis routes have been explored for this compound. Finally, theoretical calculations, based on density-functional theory and Boltzmann's transport theory, have allowed us to predict the thermoelectric properties of substituted Mn4Si7. The objectives were to find substitutional atoms leading to an improvement of the thermoelectric efficiency of Mn4Si7.

Download or read book Thermoelectric Materials written by Enrique Macia and published by CRC Press. This book was released on 2015-05-05 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental and economic concerns have significantly spurred the search for novel, high-performance thermoelectric materials for energy conversion in small-scale power generation and refrigeration devices. This quest has been mainly fueled by the introduction of new designs and the synthesis of new materials. In fact, good thermoelectric material

Download or read book Properties of Metal Silicides written by Karen Maex and published by Institution of Electrical Engineers. This book was released on 1995 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of silicon alloyed with metals are presented here for silicides of both transition and rare earth metals.

Download or read book Modules Systems and Applications in Thermoelectrics written by David Michael Rowe and published by CRC Press. This book was released on 2012-04-25 with total page 585 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprising two volumes, Thermoelectrics and Its Energy Harvesting reviews the dramatic improvements in technology and application of thermoelectric energy with a specific intention to reduce and reuse waste heat and improve novel techniques for the efficient acquisition and use of energy. This volume, Modules, Systems and Applications in Thermoelectrics, discusses the practical, novel, and truly groundbreaking applications of thermoelectrics in a range of markets. The book details the U.S. interest in alternative energy and energy harvesting, specifically, the current efforts to use thermoelectric generators (TGs) to reduce emissions. Internationally, it expounds on the strong interest in Japan, Korea and Europe to incorporate TGs in cars to reduce fuel consumption and meet EU carbon dioxide emission targets; the European plans to build an isotopic powered thermoelectric generator; and India’s use of TG s in converting hot water from steel mills into electricity.

Download or read book Thermoelectric Nanomaterials written by Kunihito Koumoto and published by Springer Science & Business Media. This book was released on 2013-07-20 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presently, there is an intense race throughout the world to develop good enough thermoelectric materials which can be used in wide scale applications. This book focuses comprehensively on very recent up-to-date breakthroughs in thermoelectrics utilizing nanomaterials and methods based in nanoscience. Importantly, it provides the readers with methodology and concepts utilizing atomic scale and nanoscale materials design (such as superlattice structuring, atomic network structuring and properties control, electron correlation design, low dimensionality, nanostructuring, etc.). Furthermore, also indicates the applications of thermoelectrics expected for the large emerging energy market. This book has a wide appeal and application value for anyone being interested in state-of-the-art thermoelectrics and/or actual viable applications in nanotechnology.

Download or read book Semiconducting Silicides written by Victor E. Borisenko and published by Springer Science & Business Media. This book was released on 2013-03-07 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive presentation and analysis of properties and methods of formation of semiconducting silicides. Fundamental electronic, optical and transport properties of the silicides collected from recent publications will help readers choose their application in new generations of solid-state devices. A comprehensive presentation of thermodynamic and kinetic data is given in combination with their technical application, as is information on corresponding thin-film or bulk crystal formation techniques.

Download or read book Electronic Properties of Materials written by Rolf E. Hummel and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book on electrical, optical, magnetic and thermal properties of materials is in many aspects different from other introductory texts in solid state physics. First of all, this book is written for engineers, particularly materials and electrical engineers who want to gain a fundamental under standing of semiconductor devices, magnetic materials, lasers, alloys, etc. Second, it stresses concepts rather than mathematical formalism, which should make the presentation relatively easy to understand. Thus, this book provides a thorough preparation for advanced texts, monographs, or special ized journal articles. Third, this book is not an encyclopedia. The selection oftopics is restricted to material which is considered to be essential and which can be covered in a 15-week semester course. For those professors who want to teach a two-semester course, supplemental topics can be found which deepen the understanding. (These sections are marked by an asterisk [*]. ) Fourth, the present text leaves the teaching of crystallography, X-ray diffrac tion, diffusion, lattice defects, etc. , to those courses which specialize in these subjects. As a rule, engineering students learn this material at the beginning of their upper division curriculum. The reader is, however, reminded of some of these topics whenever the need arises. Fifth, this book is distinctly divided into five self-contained parts which may be read independently.

Download or read book Multicomponent Silicides for Thermoelectric Materials written by Jean-Claude Tedenac and published by Springer. This book was released on 2017-06-02 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive review of the current state of the art in silicon compounds for thermoelectric applications. Silicides are materials with good initial thermoelectric properties, which can be enhanced through tuning of their micro- and macrostructure. These compounds present various conduction mechanisms and complex band structures. Moreover, some are isotropic, and others anisotropic, which is highly beneficial for device tailoring. Silicides are a particularly attractive material for sensors, thermoelectric generators, and other applications because they are environmentally friendly, abundant, and low cost. This concise volume covers fundamentals and applications for an audience of materials scientists, chemists, solid-state physicists, and engineers.

Download or read book Thermoelectric Skutterudites written by Ctirad Uher and published by CRC Press. This book was released on 2021-05-18 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: • Gives a comprehensive account of all fundamental physical properties of skutterudites. • Each major topic is accompanied by introductory sections and further detailed theoretical treatment is provided in Appendices. • Supported by many figures and a vast number of relevant references.

Download or read book High Temperature Corrosion and Materials Chemistry III written by Electrochemical Society. High Temperature Materials Division and published by The Electrochemical Society. This book was released on 2001 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Thermoelectrics written by Zhifeng Ren and published by CRC Press. This book was released on 2017-11-06 with total page 1102 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview on nanostructured thermoelectric materials and devices, covering fundamental concepts, synthesis techniques, device contacts and stability, and potential applications, especially in waste heat recovery and solar energy conversion. The contents focus on thermoelectric devices made from nanomaterials with high thermoelectric efficiency for use in large scale to generate megawatts electricity. Covers the latest discoveries, methods, technologies in materials, contacts, modules, and systems for thermoelectricity. Addresses practical details of how to improve the efficiency and power output of a generator by optimizing contacts and electrical conductivity. Gives tips on how to realize a realistic and usable device or module with attention to large scale industry synthesis and product development. Prof. Zhifeng Ren is M. D. Anderson Professor in the Department of Physics and the Texas Center for Superconductivity at the University of Houston. Prof. Yucheng Lan is an associate professor in Morgan State University. Prof. Qinyong Zhang is a professor in the Center for Advanced Materials and Energy at Xihua University of China.

Download or read book Thermoelectric Materials and Devices written by Lidong Chen and published by Elsevier. This book was released on 2020-09-25 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectric Materials and Devices summarizes the latest research achievements over the past 20 years of thermoelectric material and devices, most notably including new theory and strategies of thermoelectric materials design and the new technology of device integration. The book's author has provided a bridge between the knowledge of basic physical/chemical principles and the fabrication technology of thermoelectric materials and devices, providing readers with research and development strategies for high performance thermoelectric materials and devices. It will be a vital resource for graduate students, researchers and technologists working in the field of energy conversion and the development of thermoelectric devices. - Discusses the new theory and methods of thermoelectric materials design - Combines scientific principles, along with synthesis and fabrication technologies in thermoelectric materials - Presents the design optimization and interface technology for thermoelectric devices - Introduces thermoelectric polymers and organic-inorganic thermoelectric composites

Download or read book Heavily Doped Semiconductors written by V. I. Fistul and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, there has been a considerable upsurge of interest in heavily doped semiconductors. This interest is due primarily to the expanding range of applications of such. materials. Moreover, the heavy doping of semiconductors produces new effects (the forma tion of impurity aggregates, the appearance of allowed states in the forbidden band, etc J, which are of great interest in solid-state physics. The rapid growth in the number of papers on heavily doped semiconductors makes it difficult to review the results obtained so far. Therefore, many investigations carried out in 1966-7, par ticularly those on AIIIBV semiconductors, are not discussed in the present monograph, which represents the state of the knowledge in 1965. Nevertheless, the author hopes that, in spite of this, the book will be useful. An attempt is made, first, to review investigations of heavily doped semiconductors from a certain viewpoint and, sec ondly, to suggest some ideas (Chap. 5) which may be controversial but which are intended to stimulate further studies of heavily doped semiconductors which can be regarded as a special case of dis ordered systems. The work of American scientists investigating heavily doped semiconductors, in particular the efforts of E. O. Kane, J. 1. Pan kove, R. N. Hall, R. A. Logan, W. G. Spitzer, F. A. Trumbore, and many others, is well known to Soviet investigators. It gives me pleasure to learn that Western readers will now have an - v vi PREFACE portunity to become acquainted with the work done in the USSR.