Properties And Applications Of Nanocrystalline Alloys From Amorphous Precursors

Metallic (magnetic and non-magnetic) nanocrystalline materials have been known for over ten years but only recent developments in the research into those complex alloys and their metastable amorphous precursors have created a need to summarize the most important accomplishments in the field. This book is a collection of articles on various aspects of metallic nanocrystalline materials, and an attempt to address this above need. The main focus of the papers is put on the new issues that emerge in the studies of nanocrystalline materials, and, in particular, on (i) new compositions of the alloys, (ii) properties of conventional nanocrystalline materials, (iii) modeling and simulations, (iv) preparation methods, (v) experimental techniques of measurements, and (vi) different modern applications. Interesting phenomena of the physics of nanocrystalline materials are a consequence of the effects induced by the nanocrystalline structure. They include interface physics, the influence of the grain boundaries, the averaging of magnetic anisotropy by exchange interactions, the decrease in exchange length, and the existence of a minimum two-phase structure at the atomic scale. Attention is also paid to the special character of the local atomic ordering and to the corresponding interatomic bonding as well as to anomalies and particularities of electron density distributions, and to the formation of metastable, nanocrystalline (or quasi-crystalline) phases built from exceptionally small grains with special properties. Another important focus of attention are new classes of materials which are not based on new compositions, but rather on the original and special crystalline structure in the nanoscale.

Metallic (magnetic and non-magnetic) nanocrystalline materials have been known for over ten years but only recent developments in the research into those complex alloys and their metastable amorphous precursors have created a need to summarize the most important accomplishments in the field. This book is a collection of articles on various aspects of metallic nanocrystalline materials, and an attempt to address this above need. The main focus of the papers is put on the new issues that emerge in the studies of nanocrystalline materials, and, in particular, on (i) new compositions of the alloys, (ii) properties of conventional nanocrystalline materials, (iii) modeling and simulations, (iv) preparation methods, (v) experimental techniques of measurements, and (vi) different modern applications. Interesting phenomena of the physics of nanocrystalline materials are a consequence of the effects induced by the nanocrystalline structure. They include interface physics, the influence of the grain boundaries, the averaging of magnetic anisotropy by exchange interactions, the decrease in exchange length, and the existence of a minimum two-phase structure at the atomic scale. Attention is also paid to the special character of the local atomic ordering and to the corresponding interatomic bonding as well as to anomalies and particularities of electron density distributions, and to the formation of metastable, nanocrystalline (or quasi-crystalline) phases built from exceptionally small grains with special properties. Another important focus of attention are new classes of materials which are not based on new compositions, but rather on the original and special crystalline structure in the nanoscale.

Amorphous-nanocrystalline alloys are a relatively new class of materials born from the rapid development of new technologies and different methods of producing amorphous and nanocrystalline powders and films, compacting, melt quenching, megaplastic deformation, implantation, laser, plasma, and other high-energy methods. This book considers methods of producing these materials (melt quenching, controlled crystallization, deformation effect, and pulse treatments (photon, laser and ultrasound), spraying thin films, and ion implantation). Theoretical and experimental studies describe plastic deformation mechanisms and physico-mechanical properties. Practical applications are also presented.

Amorphous and nanocrystalline materials are a class of their own. Their properties are quite different to those of the corresponding crystalline materials. This book gives systematic insight into their physical properties, structure, behaviour, and design for special advanced applications.

Nanostructured materials have at least one dimension in the nanometer range. They became a very active research area in solid state physics and chemistry in recent years with anticipated applications in various domains, including solar cells, electronics, batteries and sensors. Nanocrystalline metals and oxides are dense polycrystalline solids with a mean grain size below 100 nm. This book is intended to give an overview on selected properties and applications of nanocrystalline metals and oxides by leading experts in the field. The first three chapters provide a very complete theoretical treatment of thermodynamics and atom/ion transport for nanocrystalline materials. The following chapters are experts' views on the development of experimental characterization techniques for nanocrystalline solids with emphasis on electroceramic materials. Nanocrystalline Metals and Oxides is intended for a broad range of readers, foremost chemists, physicists and materials scientists. Theoretical physicists and chemists will certainly also profit from this book. The electroceramics and solid state ionics community are particularly addressed, given the main interests of the editors.

Nanocrystalline FINEMET-type alloys (FeSiBCuNb ) having average grain diameter ~ 10 nm , obtained by the devitrification of rapidly solidified (typically 20 mm thick ribbons) amorphous alloys are attractive for applications due to their excellent soft magnetic properties e. g. – high saturation magnetic induction comparable with Fe-based amorphous alloys and large permeability as observed in Co-based metallic glasses. In Finemet type alloys the presence of small amount of Cu enhances the nucleation rate, while presence of Nb inhibits the grain growth, resulting in nano-crystallization which proved to be key factor for obtaining the particular ultra fine grain structure.

Amorphous and nanocrystalline materials are a class of their own. Their properties are quite different to those of the corresponding crystalline materials. This book gives systematic insight into their physical properties, structure, behaviour, and design for special advanced applications.

Nano-oxide materials lend themselves to applications in a wide variety of emerging technological fields such as microelectronics, catalysts, ceramics, coatings, and energy storage. However, developing new routes for making nano-based materials is a challenging area for solid-state materials chemists. This book does just that by describing a novel method for preparing them. The authors have developed a novel low-temperature, self-propagating synthetic route to nano-oxides by the solution combustion and combustible precursor processes. This method provides the desired composition, structure, and properties for many types of technologically useful nanocrystalline oxide materials like alumina, ceria, iron oxides, titania, yttria, and zirconia, among others.The book is particularly instructive in bringing readers one step closer to the exploration of nanomaterials. Students of nanoscience can acquaint themselves with the actual production and evaluation of nanopowders by this route, while academic researchers and industrial scientists will find answers to a host of questions on nano-oxides. The book also provides an impetus for scientists in industrial research to evaluate and explore new ways to scale up the production of nanomaterials, offering helpful suggestions for further research.

Nanostructure science and technology has become an identifiable, if very broad and multidisciplinary, field of research and emerging application in recent years. It is one of the most visible and growing research areas in materials science in its broadest sense. Nanostructured materials include atomic clusters, layered (lamellar) films, filamentary structures, and bulk nanostructured materials. The common thread to these materials is the nanoscale dimensionality, i.e. at least one dimension less than 100 nm, more typically less than 50 nm. In some cases, the physics of such nanoscale materials can be very different form the macroscale properties of the same substance, offering often superior properties that warrant much interest in these materials. Including contributions from twenty-one international contributors, Nanostructured Materials focuses on the synthesis, characterization, and properties relevant to nanostructured materials applications that require bulk and mainly inorganic materials. Topics include synthesis and processing of powders and films, thermal spray processing of nanocrystalline materials, solid state processing, nanocrystalline powder consolidation methods, electrodeposited nanocrystalline materials, computer simulation of nanomaterials, diffusion, gas reactive applications, magnetic properties, mechanical behavior, structure formation, mechanical behavior of two-phase materials, and more.