Download or read book Novel Environmental Barrier Coatings for Resistance Against Degradation by Molten Glassy Deposits in the Presence of Water Vapor written by Caitlin Maureen Toohey and published by . This book was released on 2011 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Environmental barrier coatings (EBCs) are used to prevent oxidation of underlying ceramic-matrix composite (CMC) structural components in aircraft gas-turbine engines. As operating temperatures increase, ingested airborne sand poses a serious threat to the stability of these coatings, because the sand adheres to the hot EBC surfaces and melts, forming calcium--magnesium--aluminosilicate (CMAS) glass. The reaction of EBCs with molten CMAS can lead to EBC delamination. Additionally, the interaction of water vapor with the CMAS--reacted EBCs can result in the formation of undesirable phases. Yb2Si2O-- has been identified as a promising EBC ceramic, based on its desirable properties: phase stability up to 1600°C, low thermal expansion coefficient mismatch with common CMCs, and potential resistance against degradation by CMAS and water vapor. As--sintered Yb2Si2O-- and CMAS--coated Yb2Si2O-- are tested in an air environment and in a water vapor environment, at a temperature of 1300°C in both cases. The behavior of these ceramics is compared to that of reference materials. Results from oxidation and chemical stability studies and analyses are presented.
Download or read book The Degradation of Environmental Barrier Coatings by Molten Silicates written by Kendra Marie Grant and published by . This book was released on 2010 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The volatilization of Si-based ceramic matrix composites (CMCs) in moisture-laden combustion environments is alleviated by the application of an environmental barrier coating (EBC). In principle all current (e.g. BSAS) and prospective (e.g. Y2SiO5) EBC materials are susceptible to thermochemical degradation by calcium-magnesium alumino-silicate (CMAS) deposits. The mechanism involves dissolution of the parent EBC into the CMAS melt and the precipitation of silicate reaction products. For example, BSAS in contact with the melt dissolves and re-precipitates as modified Celsian. However, the CMAS attack of BSAS involves an additional and potentially more damaging mechanism, wherein CMAS penetrates along grain boundaries to depths typically of the order of a practical coating thickness. Yttrium silicate monoliths are not susceptible to grain boundary attack; however, the primary precipitated phase, calcium-yttrium apatite (Ca2Y8(SiO 4)6O2), is not fully effective as a diffusion barrier. The apatite is interpenetrated by thin amorphous grain boundary films that allows rapid transport of the glass species to the reaction front. The secondary products and morphological characteristics of the reaction zone depend on time, temperature and whether the environment is stagnant laboratory air or flowing H2O/O2. The degradation mechanisms and their implications to the durability of EBCs in potential gas turbine applications are discussed in light of experiments exploring the effect of these variables.
Download or read book Environmental Barrier Coatings written by Kang N. Lee and published by MDPI. This book was released on 2020-12-29 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The global increase in air travel will require commercial vehicles to be more efficient than ever before. Advanced engine hot section materials are a key technology required to keep fuel consumption and emission to a minimum in next-generation gas turbines. Ceramic matrix composites (CMCs) are the most promising material to revolutionize gas turbine hot section materials technology because of their excellent high‐temperature properties. Rapid surface recession due to volatilization by water vapor is the Achilles heel of CMCs. Environmental barrier coatings (EBCs) is an enabling technology for CMCs, since it protects CMCs from water vapor. The first CMC component entered into service in 2016 in a commercial engine, and more CMC components are scheduled to follow within the next few years. One of the most difficult challenges to CMC components is EBC durability, because failure of EBC leads to a rapid reduction in CMC component life. Key contributors to EBC failure include recession, oxidation, degradation by calcium‐aluminum‐magnesium silicates (CMAS) deposits, thermal and thermo‐mechanical strains, particle erosion, and foreign object damage (FOD). Novel EBC chemistries, creative EBC designs, and robust processes are required to meet EBC durability challenges. Engine-relevant testing, characterization, and lifing methods need to be developed to improve EBC reliability. The aim of this Special Issue is to present recent advances in EBC technology to address these issues. In particular, topics of interest include but are not limited to the following: • Novel EBC chemistries and designs; • Processing including plasma spray, suspension plasma spray, solution precursor plasma spray, slurry process, PS-PVD, EB-PVD, and CVD; • Testing, characterization, and modeling; • Lifing.
Download or read book Upper Temperature Limit of Environmental Barrier Coatings Based on Mullite and BSAS written by and published by . This book was released on 2002 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental Barrier Coatings for the Energy Efficient Heat Engines Program written by Katherine Faber and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This program aimed to develop a fundamental understanding of the microstructural, mechanical, and chemical properties of Ta{sub 2}O{sub 5}-based coatings for Si{sub 3}N{sub 4} (AS800) substrates and optimize such coatings for environmental barriers. The program consisted of three tasks: processing of Ta{sub 2}O{sub 5} coatings, phase and microstructural development, and life-limiting phenomena. Northwestern University formed a cross-functional team with Lehigh University, Honeywell Inc., and Oak Ridge National Laboratory. The major accomplishments are: (1) Conditions for the plasma spray of Ta{sub 2}O{sub 5} and its alloys were optimized to provide maximum density and thickness. (2) Adherent small particle plasma spray coatings of Ta{sub 2}O{sub 5} can be routinely prepared. (3) Ta{sub 2}O{sub 5} can be stabilized against its disruptive phase transformation to 1400 C by the addition of one or more oxides of Al, La, and/or Nb. (4) Residual stresses in the Ta{sub 2}O{sub 5} coatings were measured using X-rays and changed with thermal exposure. (5) Properly doped coatings are more resistant against thermal cycling than undoped coatings, and can be cycled many thousand times without spallation. (6) Water vapor testing in the ORNL Keiser Rig of adherent coatings showed that undoped Ta{sub 2}O{sub 5} is not an effective barrier at preventing chemical changes to the AS800. (7) Limited water vapor testing of doped and adherent coatings, which had successfully survived many thermal cycles, showed that in the water vapor environment, de-cohesion may occur.
Download or read book Ceramic Fibers and Coatings written by Committee on Advanced Fibers for High-Temperature Ceramic Composites and published by National Academies Press. This book was released on 1998-05-05 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-temperature ceramic fibers are the key components of ceramic matrix composites (CMCs). Ceramic fiber properties (strength, temperature and creep resistance, for example)-along with the debonding characteristics of their coatings-determine the properties of CMCs. This report outlines the state of the art in high-temperature ceramic fibers and coatings, assesses fibers and coatings in terms of future needs, and recommends promising avenues of research. CMCs are also discussed in this report to provide a context for discussing high-temperature ceramic fibers and coatings.
Download or read book High Temperature Coatings written by Sudhangshu Bose and published by Butterworth-Heinemann. This book was released on 2017-11-27 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Temperature Coatings, Second Edition, demonstrates how to counteract the thermal effects of rapid corrosion and degradation of exposed materials and equipment that can occur under high operating temperatures. This is the first true practical guide on the use of thermally protective coatings for high-temperature applications, including the latest developments in materials used for protective coatings. It covers the make-up and behavior of such materials under thermal stress and the methods used for applying them to specific types of substrates, as well as invaluable advice on inspection and repair of existing thermal coatings. With his long experience in the aerospace gas turbine industry, the author has compiled the very latest in coating materials and coating technologies, as well as hard-to-find guidance on maintaining and repairing thermal coatings, including appropriate inspection protocols. The book is supplemented with the latest reference information and additional support to help readers find more application- and industry-type coatings specifications and uses. Offers an overview of the underlying fundamental concepts of thermally-protective coatings, including thermodynamics, energy kinetics, crystallography and equilibrium phases Covers essential chemistry and physics of underlying substrates, including steels, nickel-iron alloys, nickel-cobalt alloys and titanium alloys Provides detailed guidance on a wide variety of coating types, including those used against high temperature corrosion and oxidative degradation and thermal barrier coatings
Download or read book Modeling Volcanic Processes written by Sarah A. Fagents and published by Cambridge University Press. This book was released on 2021-02-11 with total page 902 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the physical behavior of volcanoes is key to mitigating the hazards active volcanoes pose to the ever-increasing populations living nearby. The processes involved in volcanic eruptions are driven by a series of interlinked physical phenomena, and to fully understand these, volcanologists must employ various physics subdisciplines. This book provides the first advanced-level, one-stop resource examining the physics of volcanic behavior and reviewing the state-of-the-art in modeling volcanic processes. Each chapter begins by explaining simple modeling formulations and progresses to present cutting-edge research illustrated by case studies. Individual chapters cover subsurface magmatic processes through to eruption in various environments and conclude with the application of modeling to understanding the other volcanic planets of our Solar System. Providing an accessible and practical text for graduate students of physical volcanology, this book is also an important resource for researchers and professionals in the fields of volcanology, geophysics, geochemistry, petrology and natural hazards.
Download or read book Damp Indoor Spaces and Health written by Institute of Medicine and published by National Academies Press. This book was released on 2004-10-01 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost all homes, apartments, and commercial buildings will experience leaks, flooding, or other forms of excessive indoor dampness at some point. Not only is excessive dampness a health problem by itself, it also contributes to several other potentially problematic types of situations. Molds and other microbial agents favor damp indoor environments, and excess moisture may initiate the release of chemical emissions from damaged building materials and furnishings. This new book from the Institute of Medicine examines the health impact of exposures resulting from damp indoor environments and offers recommendations for public health interventions. Damp Indoor Spaces and Health covers a broad range of topics. The book not only examines the relationship between damp or moldy indoor environments and adverse health outcomes but also discusses how and where buildings get wet, how dampness influences microbial growth and chemical emissions, ways to prevent and remediate dampness, and elements of a public health response to the issues. A comprehensive literature review finds sufficient evidence of an association between damp indoor environments and some upper respiratory tract symptoms, coughing, wheezing, and asthma symptoms in sensitized persons. This important book will be of interest to a wide-ranging audience of science, health, engineering, and building professionals, government officials, and members of the public.
Download or read book Principles of Environmental Physics written by John Monteith and published by Butterworth-Heinemann. This book was released on 1990-02-15 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thoroughly revised and up-dated edition of a highly successful textbook.
Download or read book Engineered Ceramics written by Tatsuki Ohji and published by John Wiley & Sons. This book was released on 2016-02-01 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book project, all the American Ceramic Society's Engineering Ceramics Division Mueller and Bridge Building Award Winners, the ICACC Plenary Speakers and the past Engineering Ceramics Division Chairs have been invited to write book chapters on a topic that is compatible with their technical interests and consistent with the scope of the book, which is to focus on the current status and future prospects of various technical topics related to engineering ceramics, advanced ceramics and composite materials. Topics include: Mechanical Behavior and Performance of Ceramics & Composites Non-Destructive Evaluation and Mechanical Testing of Engineering Ceramics Brittle and Composite Material Design Modern Fracture Mechanics of Ceramics Thermal/Environmental Barrier Coatings Advanced Ceramic Coatings for Functional Applications Advanced Ceramic Joining Technologies Ceramics for Machining, Friction, Wear, and Other Tribological Applications Ceramic Composites for High-Temperature Aerospace Structures and Propulsion Systems Thermal Protection Materials: From Retrospect to Foresight Carbon/Carbon Composites Ceramic-Matrix Composites for Lightweight Construction Ultra High-Temperature Ceramics (UHTC) Nanolaminated Ternary Carbides and Nitrides (MAX Phases) Ceramics for Heat Engine and Other Energy Related Applications Solid Oxide Fuel Cells (SOFC) Armor Ceramics Next Generation Bioceramics Ceramics for Innovative Energy and Storage Systems Designing Ceramics for Electrochemical Energy Storage Devices Nanostructured Materials and Nanotechnology Advanced Ceramic Processing and Manufacturing Technologies Engineering Porous Ceramics Thermal Management Materials and Technologies Geopolymers Advanced Ceramic Sensor Technology Advanced Ceramics and Composites for Nuclear and Fusion Applications Advanced Ceramic Technologies for Rechargeable Batteries
Download or read book Protein Based Films and Coatings written by Aristippos Gennadios and published by CRC Press. This book was released on 2002-02-07 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the most up-to-date and detailed information available on protein-based biopolymer films and coatings. It provides a comprehensive overview of the design, technology, properties, functionality, and applications of biopolymer films and coatings (edible and inedible) from plant and animal proteins. Both widely commercialized and
Download or read book Lunar Sourcebook written by Grant Heiken and published by CUP Archive. This book was released on 1991-04-26 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only work to date to collect data gathered during the American and Soviet missions in an accessible and complete reference of current scientific and technical information about the Moon.
Download or read book Extrusion written by Harold F. Giles Jr and published by William Andrew. This book was released on 2013-09-21 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Extrusion is designed to aid operators, engineers, and managers in extrusion processing in quickly answering practical day-to-day questions. The first part of the book provides the fundamental principles, for operators and engineers, of polymeric materials extrusion processing in single and twin screw extruders. The next section covers advanced topics including troubleshooting, auxiliary equipment, and coextrusion for operators, engineers, and managers. The final part provides applications case studies in key areas for engineers such as compounding, blown film, extrusion blow molding, coating, foam, and reprocessing. This practical guide to extrusion brings together both equipment and materials processing aspects. It covers basic and advanced topics, for reference and training, in thermoplastics processing in the extruder. Detailed reference data are provided on such important operating conditions as temperatures, start-up procedures, shear rates, pressure drops, and safety. A practical guide to the selection, design and optimization of extrusion processes and equipment Designed to improve production efficiency and product quality Focuses on practical fault analysis and troubleshooting techniques
Download or read book Introduction to Glass Science and Technology written by James E Shelby and published by Royal Society of Chemistry. This book was released on 2015-11-06 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a concise and inexpensive introduction for an undergraduate course in glass science and technology. The level of the book has deliberately been maintained at the introductory level to avoid confusion of the student by inclusion of more advanced material, and is unique in that its text is limited to the amount suitable for a one term course for students in materials science, ceramics or inorganic chemistry. The contents cover the fundamental topics of importance in glass science and technology, including glass formation, crystallization, phase separation and structure of glasses. Additional chapters discuss the most important properties of glasses, including discussion of physical, optical, electrical, chemical and mechanical properties. A final chapter provides an introduction to a number of methods used to form technical glasses, including glass sheet, bottles, insulation fibre, optical fibres and other common commercial products. In addition, the book contains discussion of the effects of phase separation and crystallization on the properties of glasses, which is neglected in other texts. Although intended primarily as a textbook, Introduction to Glass Science and Technology will also be invaluable to the engineer or scientist who desires more knowledge regarding the formation, properties and production of glass.
Download or read book Active Protective Coatings written by Anthony E. Hughes and published by Springer. This book was released on 2016-03-01 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers a broad range of materials science that has been brought to bear on providing solutions to the challenges of developing self-healing and protective coatings for a range of metals. The book has a strong emphasis on characterisation techniques, particularly new techniques that are beginning to be used in the coatings area. It features many contributions written by experts from various industrial sectors which examine the needs of the sectors and the state of the art. The development of self-healing and protective coatings has been an expanding field in recent years and applies a lot of new knowledge gained from other fields as well as other areas of materials science to the development of coatings. It has borrowed from fields such as the food and pharmaceutical industries who have used, polymer techniques, sol-gel science and colloidosome technology for a range encapsulation techniques. It has also borrowed from fields like hydrogen storage such as from the development of hierarchical and other materials based on organic templating as “nanocontainers” for the delivery of inhibitors. In materials science, recent developments in high throughput and other characterisation techniques, such as those available from synchrotrons, are being increasing used for novel characterisation – one only needs to look at the application of these techniques in self healing polymers to gauge wealth of new information that has been gained from these techniques. This work is largely driven by the need to replace environmental pollutants and hazardous chemicals that represent risk to humans such as chromate inhibitors which are still used in some applications.
Download or read book Lectures on Materials Science for Architectural Conservation written by Giorgio Torraca and published by . This book was released on 2009-12-01 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on Dr. Torraca's 2002 publication, Lezioni di scienza e tecnologia dei materiali per restauro dei monumenti. The English-language Lectures includes new and updated material. An excellent resource for architectural conservators, engineers, and conservation scientists.
