Bøger i Materials Research Foundations serien

A novel method of concrete mix design is presented. Tests with various constituent materials are reported in great detail. Both laboratory tests and applications in industry show the method to be very successful for all kinds of normal constituent materials, including silica fume, ground granulated blast furnace slag, fly ash, natural pozzolans, blended cement, fine and coarse aggregates, water, air entraining admixtures, plasticizers and super-plasticizers.

Thin phosphate coatings are very attractive technologically; in terms of reliability, manufacturing cost and environmental impact. For one thing, the book presents research aimed at obtaining thin phosphate layers that offer good corrosion protection of finished parts. The other aim was to develop techniques that result in coatings with good lubricating properties, as they are required in plastic deformation processing. Presented are alternatives to obtain and characterize phosphate layers by means of the co-precipitation of cations and surfactants in acidic aqueous solutions; resulting in the production of dendritic structures with optimal chemical, physical-structural and mechanical properties. Decisive here are the processes of nucleation and the formation of compact layers that are uniform and well adherent to the substrate. Another general aim was the development of phosphating technologies with high reliability, minimal use of materials and energy and with minimal impact on the environment and operator.

Characterization, design, specific properties and applications of thermoset composites are reported. These composites are presently in high demand because they can be shaped into many-sided segments and structures, and can have a great variety of densities and special physical and mechanical properties. The research reported includes: Energy absorption of fiber reinforced composites; automotive crashworthiness; lignocellulosic composites; hybrid bast fiber reinforced composites; nano-carbon/polymer composites; electromagnetic shielding; structural mechanical applications; electromagnetic field emission applications, conductive composites; epoxy composites for structural purposes; tribological performance of polymeric composites.

This compendium reports fundamental science and engineering advances of the US Army Research Labratory (ARL) within the area of Energy and Power technologies. Although, in general, ARL's Materials Research encompasses a broad range of materials technologies (e.g.: Photonics, Electronics, Biological and Bio-inspired Materials, Structural Materials, High Strain and Ballistic Materials, and Manufacturing Science), this publication specifically addresses selected energy and power material related work at ARL. While this work includes electrochemical energy storage (batteries and capacitors) and electrochemical energy conversion (fuel cells, photoelectrochemistry, and photochemistry), special emphasis is given on electrochemical energy storage: • Micro Electro-Mechanical Systems (MEMS): Power density, efficiency, and robustness of motors, generators, and actuators while also reducing their life cycle costs. • Energy Storage: Electrical and electrochemical energy storage devices to decrease device size, weight, and cost as well as increase their capabilities in extreme temperatures and operating conditions. • Power Control and Distribution: Tactical, deployable power systems using conventional fuels, alternative fuels, and energy harvested from renewable/ambient sources. • Power Generation/Energy Conversion: Smart energy networks for platforms, forward operating bases, and facilities using modeling and simulation tools as well as new, greater capability and efficiency components. • Thermal Transport and Control: Heat and higher power density systems, advanced components, system modeling, and adaptive or hybrid-cycle technologies.Keywords Electrochemical Energy Storage, Batteries, Capacitors, Electrochemical Energy Conversion, Fuel Cells, Photoelectrochemistry, Photochemistry, High Voltage Electrolytes, Li-ion Batteries, Li-ion Chemistry, Lithium-Sulphur Batteries, Nuclear Metastables, Pyroelectric Energy Conversion, Charged Quantum Dots, High-Efficiency Photovoltaics, IR Sensing, GaN Power Schottky Diodes, Threshold-Voltage Instability, Reliability Testing, SiC MOSFETs, Power Electronics Packaging, High Voltage 4H-SiC GTOs, Silicon Carbide, Avalanche Breakdown Diode, SiC PiN Diodes, Thyristor Protection, Compact DC-DC Battery Chargers

The rapidly advancing Silicon Carbide technology has a great potential in high temperature and high frequency electronics. High thermal stability and outstanding chemical inertness make SiC an excellent material for high-power, low-loss semiconductor devices. The present volume presents the state of the art of SiC device fabrication and characterization. Topics covered include: SiC surface cleaning and etching techniques; electrical characterization methods and processing of ohmic contacts to silicon carbide; analysis of contact resistivity dependence on material properties; limitations and accuracy of contact resistivity measurements; ohmic contact fabrication and test structure design; overview of different metallization schemes and processing technologies; thermal stability of ohmic contacts to SiC, their protection and compatibility with device processing; Schottky contacts to SiC; Schottky barrier formation; Schottky barrier inhomogeneity in SiC materials; technology and design of 4H-SiC Schottky and Junction Barrier Schottky diodes; Si/SiC heterojunction diodes; applications of SiC Schottky diodes in power electronics and temperature/light sensors; high power SiC unipolar and bipolar switching devices; different types of SiC devices including material and technology constraints on device performance; applications in the area of metal contacts to silicon carbide; status and prospects of SiC power devices.

Diluted Magnetic Semiconductors (DMS) play a vital role in modern electronics industry. It is important to understand the fundamental properties of these materials in order to apply them to their full potential. This book presents an analysis of the charge density distribution and other properties of some silicon and germanium based diluted magnetic semiconductors. A quantitative analysis of the charge density distribution has been done in order to obtain measurements of the charges involved in the bonding, which are decisive for the physical and chemical properties of the DMS materials. Also, the local structures of the materials have been analyzed by studying their powder X-ray diffraction intensities. Analysis of the magnetic properties of the DMS materials is mandatory and has been accomplished by magnetic measurements carried out using a vibrating sample magnetometer. The morphology of the DMS materials has been studied using scanning electron micrographs.

Magnetic oxides, their composites and nanoparticles are uniquely suited for a wide variety of applications in new technologies, including device miniaturization, power efficiency improvement and health sector innovations. The interest in these materials is due to such properties as high resistivity, low dielectric and magnetic losses, good corrosion resistance and favorable mechanical characteristics. The book focuses on the relevant basic concepts, as well as on synthesis routes and important applications of spinel ferrites, hexaferrites and magnetic oxide nanomaterials.