Carbon at High Temperatures


Book Description

This book deals with the properties and behavior of carbon at high temperatures. It presents new methods and new ways to obtain the liquid phase of carbon. Melting of graphite and the properties of liquid carbon are presented under stationary heat and pulse methods. Metal like properties of molten graphite at high initial density are indicated. A new possible transition of liquid carbon from metal to nonmetal behavior much above the melting point is mentioned. Methodical questions of pulse heating, in particular the role of pinch-pressure in receiving a liquid state of carbon, are discussed. The reader finds evidence about the necessity of applying high pressure (higher than 100 bar) to melt graphite (melting temperature 4800±100 K). The reader can verify the advantage of volume pulse electrical heating before surface laser heating to study the physical properties of carbon, including enthalpy, heat capacity, electrical resistivity and temperature. The advantages of fast heating of graphite by pulsed electric current during a few microseconds are shown. The data obtained for the heat capacity of liquid carbon under constant pressure and constant volume were used to estimate the behavior at temperatures much higher 5000 K.













High Temperature Oxidation and Corrosion of Metals


Book Description

The book is concerned with understanding the fundamental mechanisms of high temperature alloy oxidation. It uses this understanding to develop methods of predicting oxidation rates and the way they change with temperature, gas chemistry and alloy composition. The focus is on designing (or selecting) alloy compositions which provide optimal resistance to attack by corrosive gases. . Emphasises quantitative calculations for predicting reaction rates and the effects of temperature, oxidant activities and alloy compositions. . Uses phase diagrams and diffusion paths to analyse and interpret scale structures and internal precipitation distributions . Provides a detailed examination of corrosion in industrial gases (water vapour effects, carburisation and metal dusting, sulphidation) . Text is well supported by numerous micrographs, phase diagrams and tabulations of relevant thermodynamic and kinetic data . Combines physical chemistry and materials science methodologies.




Ultra-High Temperature Materials I


Book Description

This exhaustive work in three volumes with featuring cross-reference system provides a thorough overview of ultra-high temperature materials – from elements and chemical compounds to alloys and composites. Topics included are physical (crystallographic, thermodynamic, thermo-physical, electrical, optical, physico-mechanical, nuclear) and chemical (solid-state diffusion, interaction with chemical elements and compounds, interaction with gases, vapours and aqueous solutions) properties of the individual physico-chemical phases and multi-phase materials with melting (or sublimation) points over or about 2500 °C. The first volume focuses on carbon (graphite/graphene) and refractory metals (W, Re, Os, Ta, Mo, Nb, Ir). The second and third volumes are dedicated solely to refractory (ceramic) compounds (oxides, nitrides, carbides, borides, silicides) and to the complex materials – refractory alloys, carbon and ceramic composites, respectively. It will be of interest to researchers, engineers, postgraduate, graduate and undergraduate students in various disciplines alike. The reader is provided with the full qualitative and quantitative assessment for the materials, which could be applied in various engineering devices and environmental conditions at ultra-high temperatures, on the basis of the latest updates in the field of physics, chemistry, materials science, nanotechnology and engineering.







Wettability at High Temperatures


Book Description

The purpose of this book is to bring together current scientific understanding of wetting behaviour that has been gained from theoretical models and quantitative experimental observations. The materials considered are liquid metals or inorganic glasses in contact with solid metals or ceramics at temperatures of 200-2000oC. Wetting has been a significant scientific concern for the last two centuries and reference will be made to classical work by nineteenth century scientists such as Dupré, Laplace and Young that was validated by observations of the behaviour of chemically inert ambient temperature systems.In attempting to achieve the aims of the book, the text has been divided into ten Chapters that can be grouped into four stages of presentation. The first stage comprises two Chapters that review established and newly developed models for their relevance to wetting behaviour at high temperatures, including recent models that encompass the role of chemical reactions at the solid/liquid interfaces. Attention is paid both to equilibrium wetting behaviour (Chapter 1) and to the factors that control the approach to equilibrium (Chapter 2). Then follow Chapters concerned with experimental techniques for scientific measurement of the extent of wetting (Chapter 3) and with the surface energy data for both metals and non-metals that are essential for quantitative interpretation of wetting behaviour (Chapter 4). Descriptions of experimentally determined and quantified wetting behaviour are presented and interpreted in the third part comprising five Chapters dealing with the characteristics of metal/metal, metal/oxide, metal/non-oxide, metal/carbon and molten glass/solid systems. The book concludes with a Chapter commenting on the role of wetting behaviour in joining similar and dissimilar materials by liquid route techniques.




Progress in the high-temperature synthesis of atomically dispersed metal on carbon and understanding of their formation mechanism


Book Description

The development of various high-performance electrochemical devices is crucial for mitigating the global climate crisis, and thus the design and fabrication of advanced electrode materials is highly significant. Currently, atomically dispersed metal on catalysts (ADMCs) have shown great potential in boosting the performance of various energy storage/conversion devices involving aqueous and aprotic catalytic processes, including fuel cells, water electrolyzers, CO2 electrolyzers, metal-air batteries, and metal-sulfur batteries, as well as systems involving noncatalytic deposition/adsorption of metals. To date, several reliable fabrication methodologies that can ensure the formation of ADMCs have been demonstrated, and continuous optimization is still being performed. To further reinforce the basic scientific research and promote possible practical applications of these materials, we have analyzed, compared, and summarized progress in the fabrication methodology and formation mechanism of ADMCs in this review. This review aims to draw a comprehensive picture of the current methodology and underlying mechanism in the field of material fabrication to serve as guidance for future material design.