Materialeprøvning

The study of defects and disorder in solids remains a central topic in solid state science. Developments in the field continue to be promoted by new experimental and theoretical techniques, while further impetus for the study of disorder in solids is provided by the growing range of applications of solid state materials in which disorder at the atomic level plays a crucial rOle. In this book we attempt to present a survey of fundamental and applied aspects of the field. We consider the basic aspects of defective crystalline and amorphous solids. We discuss recent studies of structural, electronic, transport, thermodynamic and spectroscopic properties of such materials. Experimental and theoretical methodologies are reviewed, and detailed consideration is given to materials such as fast ion conductors and amorphous semiconductors that are of importance in an applied context. Any survey of this large field is necessarily selective. We have chosen to emphasise insulating (especially oxidic) and semi-conducting materials. But many of the approaches and techniques we describe apply generally across the entire field of solid state science. This volume is based on a NATO ASI held at the Residencia Santa Teresa de Jesus, Madrid in September 1991. The Editor is grateful to the NATO Scientific Affairs Division for their sponsorship of this School. Thanks are also due to all who participated in and lectured at the school, but especially to the organising committee of A. V. Chadwick, G. N. Greaves, M. Grigorkiewicz, J. H. Harding and S. Kalbitzer. C. R. A.

This thesis describes the development of a new technique to solve an important industrial inspection requirement for a high-value jet-engine component. The work ¿ and the story told in the thesis ¿ stretches all the way from the fundamentals of wave propagation in anisotropic material and ultrasonic array imaging through to device production and site trials. The book includes a description of a new method to determine crystallographic orientation from 2D ultrasonic array data. Another new method is described that enables volumetric images of an anisotropic material to be generated from 2D ultrasonic array data, based on measured crystallographic orientation. After extensive modeling, a suitable 2D array and deployment fixtures were manufactured and tested on in situ turbine blades in real engines. The final site trial indicated an order of magnitude improvement over the best existing technique in the detectability of a certain type of root cracking. The Development of a 2D Ultrasonic Array Inspection for Single Crystal Turbine Blades should be an inspiration for those starting out on doctoral degrees as it shows the complete development cycle from basic science to industrial usage.

After epoxy resins and polyimides, cyanate esters arguably form the most well-developed group of high-temperature, thermosetting polymers. They possess a number of desirable performance characteristics which make them of increasing technological importance, where their somewhat higher costs are acceptable. The principal end uses for cyanate esters are as matrix resins for printed wiring board laminates and structural composites. For the electronics markets, the low dielectric loss characteristics, dimen- sional stability at molten solder temperatures and excellent adhesion to conductor metals at temperatures up to 250(deg)C, are desirable. In their use in aerospace composites, unmodified cyanate esters offer twice the frac- ture toughness of multifunctional epoxies, while achieving a service tem- perature intermediate between epoxy and bis-maleimide capabilities. Applications in radome construction and aircraft with reduced radar signatures utilize the unusually low capacitance properties of cyanate esters and associated low dissipation factors. While a number of commercial cyanate ester monomers and prepoly- mers are now available, to date there has been no comprehensive review of the chemistry and recent technological applications of this versatile family of resins. The aims of the present text are to present these in a com- pact, readable form. The work is primarily aimed at materials scientists and polymer technologists involved in research and development in the chemical, electronics, aerospace and adhesives industries. It is hoped that advanced undergraduates and postgraduates in polymer chemistry and technology, and materials science/technology will find it a useful introduc- tion and source of reference in the course of their studies.

Resin Transfer Moulding and other similar 'liquid moulding' manufacturing methods have been used to make non-structural composites for the last 35 years. However, in the last eight years these methods have become the subject of enormous interest by aerospace manufacturing companies. Resin Transfer Moulding for Aerospace Structures describes all aspects of Resin Transfer Moulding (RTM) for aerospace structures. Written by an international team of experts, from both industry and academia, it is a comprehensive work providing complete and detailed information on the process of RTM from theoretical modelling to practical experience. With subjects including manufacturing, tooling, fabric design and flow modelling all covered, this book is an invaluable up-to-the-minute reference source which provides the reader with a good understanding of RTM and its possible uses, especially for high performance applications. Resin Transfer Moulding for Aerospace Structures is an ideal guide for those in the aerospace and related industries, who want to understand and utilize RTM, as well as those directly involved in the RTM industry.

Few scientific developments in recent years have captured the popular imagination like the subject of'biodegradable' plastics. The reasons for this are complex and lie deep in the human subconscious. Discarded plastics are an intrusion on the sea shore and in the countryside. The fact that nature's litter abounds in the sea and on land is acceptable because it is biodegradable - even though it may take many years to be bioassimilated into the ecosystem. Plastics litter is not seen to be biodegradable and is aesthetically unacceptable because it does not blend into the natural environment. To the environmentally aware but often scientifically naive, biodegradation is seen to be the ecologically acceptable solution to the problem of plastic packaging waste and litter and some packaging manufacturers have exploited the 'green' consumer with exaggerated claims to 'environmentally friendly' biodegradable packaging materials. The principles underlying environmental degradation are not understood even by some manufacturers of 'biodegradable' materials and the claims made for them have been categorized as 'deceptive' by USA legislative authorities. This has set back the acceptance of plastics with controlled biodegradability as part of the overall waste and litter control strategy. At the opposite end of the commercial spectrum, the polymer manufactur- ing industries, through their trade associations, have been at pains to discount the role of degradable materials in waste and litter management. This negative campaign has concentrated on the supposed incompatibility of degradable plastics with aspects of waste management strategy, notably materials recycling.

Micro Electro Mechanical Systems (MEMS) is already about a billion dollars a year industry and is growing rapidly. So far major emphasis has been placed on the fabrication processes for various devices. There are serious issues related to tribology, mechanics, surfacechemistry and materials science in the operationand manufacturingof many MEMS devices and these issues are preventing an even faster commercialization. Very little is understood about tribology and mechanical properties on micro- to nanoscales of the materials used in the construction of MEMS devices. The MEMS community needs to be exposed to the state-of-the-artoftribology and vice versa. Fundamental understanding of friction/stiction, wear and the role of surface contamination and environmental debris in micro devices is required. There are significantadhesion, friction and wear issues in manufacturing and actual use, facing the MEMS industry. Very little is understood about the tribology of bulk silicon and polysilicon films used in the construction ofthese microdevices. These issues are based on surface phenomenaand cannotbe scaled down linearly and these become increasingly important with the small size of the devices. Continuum theory breaks down in the analyses, e. g. in fluid flow of micro-scale devices. Mechanical properties ofpolysilicon and other films are not well characterized. Roughness optimization can help in tribological improvements. Monolayers of lubricants and other materials need to be developed for ultra-low friction and near zero wear. Hard coatings and ion implantation techniques hold promise.

Biomedical Engineering Program between Rutgers University and the University of Medicine and Dentistry of New Jersey entitled "e;Biopolymers"e; and "e;Patho- biology"e; during the past 15 years. It is our hope that this book will provide the reader with all the infor- mation necessary to understand the complexity of the biological reactions that are set into motion by implantation of a material or a device. We hope that this book will provide a framework for thinking about implant interactions with bio- logical systems. Although the field of studying pathobiological responses to im- plants is still in its infancy, we are now more aware of acute and chronic con- ditions that generate inflammatory responses as a result of wear debris, activation of complement, and acute hypersensitivity. As we learn more concerning these responses, it is hoped that our ability to design implants will also improve. We encourage readers to send to us any suggestions of additional topics that they would like to see covered in our book. Frederick H. Silver David L.

Polymer science is a technology-driven science. More often than not, technological breakthroughs opened the gates to rapid fundamental and theoretical advances, dramatically broadening the understanding of experimental observations, and expanding the science itself. Some of the breakthroughs involved the creation of new materials. Among these one may enumerate the vulcanization of natural rubber, the derivatization of cellulose, the giant advances right before and during World War II in the preparation and characterization of synthetic elastomers and semi­ crystalline polymers such as polyesters and polyamides, the subsequent creation of aromatic high-temperature resistant amorphous and semi-crystal­ line polymers, and the more recent development of liquid-crystalline polymers mostly with n~in-chain mesogenicity. other breakthroughs involve the development of powerful characterization techniques. Among the recent ones, the photon correlation spectroscopy owes its success to the advent of laser technology, small angle neutron scattering evolved from n~clear reactors technology, and modern solid-state nuclear magnetic resonance spectroscopy exists because of advances in superconductivity. The growing need for high modulus, high-temperature resistant polymers is opening at present a new technology, that of more or less rigid networks. The use of such networks is rapidly growing in applications where they are used as such or where they serve as matrices for fibers or other load­ bearing elements. The rigid networks are largely aromatic. Many of them are prepared from multifunctional wholly or almost-wholly aromatic kernels, while others contain large amount of stiff difunctional residus leading to the presence of many main-chain "liquid-crystalline" segments in the "infinite" network.

Ever since the first volume appeared in 1969, this series has received good reviews in a variety of periodicals published in different corners of the world. It would seem that the work has fulfilled its purpose as outlined in the Preface to Volume 1. The rapidly increasing interest in surface and colloid science by people engaged in industrial research and development, and in environmental, ecological, medical, pharmaceutical, and other areas, justifies the continuation of such an effort. The Surface and Colloid Science series originated with John Wiley and Sons and has been continued with Plenum Press. This volume is the third with the present publisher, and is the best assurance of our mutual interest to proceed with this work. Some books in the series, as was the case with Volume 11, may appear under the editorship of other workers in the field. For reasons of continuity, a sequential numbering system will be maintained. This editor hopes to provide the scientific and technical community with high-quality contributions in surface and colloid science in the future. He invites specialists to submit definitive chapters on any topic within the broad area of our discipline for inclusion in this series.

This book represents the proceedings of the First International Conference on Frontiers of Polymer Research held in New Delhi, India during January 20-25, 1991. Polymers have usually been perceived as substances to be used in insulations, coatings, fabrics, and structural materials. Defying this classical view, polymers are emerging as a new class of materials with potential applications in many new technologies. They also offer challenging opportunities for fundamental research. Recognizing a tremendous growth in world wide interest in polymer research and technology, a truly global "1st International Conference on Frontiers of Polymer Research" was organized by P. N. Prasad (SUNY at Buffalo), F. E. Karasz (University of Massachusetts) and J. K. Nigam (Shriram Institute for Industrial Research, India). The 225 participants represented 25 countries and a wide variety of academic, industrial and government groups. The conference was inaugurated by the Prime Minister of India, Mr. Chandra Shekhar and had a high level media coverage. The focus of the conference was on three frontier areas of polymer research: (i) Polymers for photonics, where nonlinear optical properties of polymers show great promise, (ii) Polymers for electronics, where new conduction mechanisms and photophysics have generated considerable enthusiasm and (iii) High performance polymers as new advanced polymers have exhibited exceptionally high mechanical strength coupled with light weight.

Number 25 of this acclaimed series breaks new ground with articles on charge transfer across liquid-liquid interfaces, electrochemical techniques to study hydrogen ingress in metals, and electrical breakdown of liquids. Also included are articles on the measurement of corrosion and ellipsometry, bringing these older subjects up to date.

This volume chronicles the proceedings of the Third Symposium on Metallized Plastics: Fundamental and Applied Aspects held under the auspices of the Dielectric Science and Technology Division of the Electrochemical Society in Phoenix, Arizona, October 13-18, 1991. This series of symposia to address the subject of metallized plastics was initiated in 1988 and the premier symposium was held in Chicago, October 10-12, 1988, followed by the second event in Montreal, Canada, May 7-10, 1990. The rroceedings of these two symposia have been properly documented ,2. The third symposium was a huge success like the previous two events, and all this is testimonial to the brisk interest and high tempo of R&D activity in the fie14 of metallized plastics. This further bolsters our earlier thinking that there was a conspicuous need to hold symposia on this topic on a regular basis and the fourth is planned for May 16-21, 1993 in Honolulu, Hawaii. The study of metallized plastics constitutes an important human endeavor l and as pointed out earlier there are myriad applications of metallized plastics ranging from very commonplace to exotic. Also a survey of the recent literature will reveal that both the fundamental and applied aspects of metallized plastics are being pursued with great vigor.

The term biotechnology has emerged on the contemporary scene fairly recently, but the basic concept of utilizing natural materials, either directly or in modified versions, dates back to antiquity. If we search the ancient literature, such as the Bible, we find hundreds of examples wherein people employed, or modified, natural materials for a variety of important uses. As far back as the days of Noah we find pitch, a natural material, being used as a caulk. Clothing was made from animal skins and the products of several plants. Today, we would consider these things as important biotechnological developments. Likewise, the human use of polymeric materials also has a long his­ tory. In fact, many of the original materials used by mankind were poly­ mers derived from nature, such as wood, flax, cotton, wool and animal skins, which were used for shelter and clothing. In recent years, however, the concept of biotechnology has taken on a new and renewed role in our society. This is due to a combination of factors, including an increased interest in environmental concerns and the desire to break free from the stranglehold that petrochemicals have placed on our society. If we can manufacture some of our polymers from renewable resources, then we can expect to prepare them for many more years into the future than we might if we could only depend on the petro­ chemical resources.

Determining the elemental composition of surfaces is an essential measurement in characterizing solid surfaces. At present, many ap­ proaches may be applied for measuring the elemental and molecular composition of a surface. Each method has particular strengths and limitations that often are directly connected to the physical processes involved. Typically, atoms and molecules on the surface and in the near surface region may be excited by photons, electrons, ions, or neutrals, and the detected particles are emitted, ejected, or scattered ions or electrons. The purpose of this book is to bring together a discussion of the surface compositional analysis that depends on detecting scattered or sputtered ions, and the methods emphasized are those where instruments are commercially available for carrying out the analysis. For each topic treated, the physical principles, instrumentation, qualitative analysis, artifacts, quantitative analysis, applications, opportunities, and limita­ tions are discussed. The first chapter provides an overview of the role of elemental composition in surface science; compositional depth profiling; stimulation by an electric field, electrons, neutrals, or photons and detection of ions; and then stimulation by ions, and detection of ions, electrons, photons, or neutrals.

This book comprises the proceedings of the Conference and Exhibition on Non Destructive Evaluation (NDE 2020). The contents of the volume encompass a vast spectrum from Conventional to Advanced NDE including novel methods, instrumentation, sensors, procedures, and data analytics as applied to all industry segments for quality control, periodic maintenance, life estimation, structural integrity and related areas. This book will be a useful reference for students, researchers and practitioners.

This book focuses on recent advances in dental gold alloys and gold nanoparticles (GNPs) for biomedical applications. Dental gold alloys combine several highly desirable mechanical properties, such as high strength, ductility, and elasticity, with an extremely robust chemical stability in the mouth. Moreover, astonishing progress has been made in the use of GNPs as novel gold biomaterials that provide a multifunctional platform for cellular imaging, biosensing, and targeted drug delivery in tumour immunotherapy and photothermal therapy.Beginning with a comprehensive overview of the development and use of dental gold alloys, the book addresses the materials properties that are crucial for dental applications, focusing on aspects such as microstructure, chemical and mechanical stability, ageing, biocompatibility, and colour retention. The book then shifts focus to the use of GNPs in dental applications, delving into different techniques of GNP synthesis for specifically tailoring the size, shape, and stability of GNPs in biological media. In addition to these factors, it addresses how their exposure route, surface chemistry, as well as how the steric effects of their coating impact biodistribution and determine the level of GNP toxicity in the human body. Featuring topical literature reviews alongside up-to-date published experimental results, this book offers an attractive resource for practicing scientists and engineers working in the field of gold-based biomaterials.

John Keats, writing to Fanny Brawne [1], said "I long to believe in immortality ¿¿¿¿¿ I wish to believe in immortality - I wish to live with you forever". So much of this talk will be concerned with the ductile behaviour of crystals, plasticity in its narrower sense. We shall consider a crystal which is deforming by slip, and shall expose a surface in this crystal. We first think of the sur­ face as a simple mathematical cut along a low-index plane. Then we allow for the relaxation of the newly-exposed atoms, and for surface irregularities, and we consider the effect of lattice va­ cancies which can enter at the surface. We consider the effect of dissolving off the surface layers, either intermittently or contin­ uously. Then the effects of adsorption or oxidation by normal con­ stituents of the atmosphere must be considered, the effects of sur­ face alloying, and finally those of special surface-active agents. But "All/Life death does end and each day dies with sleep" [2], and plasticity in its broader sense includes the fracture ~'1hich term­ inates flow. Here there is a bewildering array of effects. The medium in which the crystal flows may enhance its ductility enor­ mously, or it may cause it to break almost without plastic deform­ ation, or under a load which it has already supported.

This Advanced Study Institute on the topic of SOLID STATE MICROBATTERIES is the third and final institute on the general theme of a field of study now termed "e;SOLID STATE IONICS"e;. The institute was held in Erice, Sicily, Italy, 3 - 15 July 1988. The objective was to assemble in one location individuals from industry and academia expert in the fields of microelectronics and solid state ionics to determine the feasibility of merging a solid state microbattery with microelectronic memory. Solid electrolytes are in principle amenable to vapor deposition, RF or DC sputtering, and other techniques used to fabricate microelectronic components. A solid state microbattery 1 1 mated on the same chip carrier as the chip can provide on board memory backup power. A solid state microbattery assembled from properly selected anode/solid electrolyte/cathode materials could have environmental endurance properties equal or superior to semiconductor memory chips. Lectures covering microelectronics, present state-of-art solid state batteries, new solid electrolyte cathode materials, theoretical and practical techniques for fabrication of new solid electrolytes, and analytical techniques for study of solid electrolytes were covered. Several areas where effort is required for further understanding of materials in pure form and their interactions with other materials at interfacial contact points were identified. Cathode materials for solid state batteries is one particular research area which requires attention. Another is a microscopic model of conduction in vitreous solid electrolytes to enhance the thermodynamic macroscopic Weak ~lectrolyte Iheory (WET).