Download or read book Oxidation and Catalytic Efficiency of ZrB2 and HfB2 Based Ultra high temperature Ceramic UHTC Composites Exposed to Supersonic Air Plasma written by Jochen Marschall and published by . This book was released on 2004 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the activities and results of experimental and modeling activities performed for the Air Force Office of Scientific Research (AFOSR) under Contract F49620-01-C-0026, "Oxidation and Catalytic Efficiency of ZrB2 and HfB2 Based Ultra-High-Temperature Ceramic (UHTC) Composites Exposed to Supersonic Air Plasma." The goals of this project were to (1) experimentally investigate UHTC oxidation in a supersonic oxidizing flow environment, (2) develop oxidation models that could be incorporated into aerothermal heating and trajectory codes, and (3) experimentally characterize the catalytic efficiency of UHTC samples for surface recombination of dissociated oxygen and nitrogen. Given the importance of impact damage to the leading edges of hypersonic vehicles, a task was added during the third year of the project to (4) begin preliminary high-velocity impact experiments on UHTC materials. Research efforts and accomplishments in each of these four areas are summarized below. The results of this research have led to eight presentations at various conferences and meetings, and have been written up in three technical publications 1-3. Manuscripts of these technical papers are included in this report as Appendixes I, II, and III.
Download or read book Mechanical Properties and Performance of Engineering Ceramics and Composites IV Volume 30 Issue 2 written by Dileep Singh and published by John Wiley & Sons. This book was released on 2009-12-15 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gain insight into the mechanical properties and performance of engineering ceramics and composites. This collection of articles illustrates the Mechanical Behavior and Performance of Ceramics & Composites symposium, which included over 100 presentations representing 10 countries. The symposium addressed the cutting-edge topics on mechanical properties and reliability of ceramics and composites and their correlations to processing, microstructure, and environmental effects.
Download or read book Oxidation of Ultra High Temperature Ceramics in Water Vapor written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra High Temperature Ceramics (UHTCs) including HfB2 + 20v/0 SiC (HS), ZrB2 + 20v/0 SiC (ZS), and ZrB2 + 30v/0 C + 14v/0 SiC (ZCS) have been investigated for use as potential aeropropulsion engine materials. These materials were oxidized in water vapor (90 percent) using a cyclic vertical furnace at 1 atm. The total exposure time was 10 h at temperatures of 1200, 1300, and 1400 C. CVD SiC was also evaluated as a baseline for comparison. Weight change, X-ray diffraction analyses, surface and cross-sectional SEM and EDS were performed. These results are compared with tests ran in a stagnant air furnace at temperatures of 1327 C for 100 min, and with high pressure burner rig (HPBR) results at 1100 and 1300 C at 6 atm for 50 h. Low velocity water vapor does not make a significant contribution to the oxidation rates of UHTCs when compared to stagnant air. The parabolic rate constants at 1300 C, range from 0.29 to 16.0 mg(sup 2)cm(sup 4)/h for HS and ZCS, respectively, with ZS results between these two values. Comparison of results for UHTCs tested in the furnace in 90 percent water vapor with HPBR results was difficult due to significant sample loss caused by spallation in the increased velocity of the HPBR. Total recession measurements are also reported for the two test environments. Nguyen, QuynhGiao N. and Opila, Elizabeth J. and Robinson, Raymond C. Glenn Research Center NASA/TM-2004-212923, E-14363
Download or read book Oxidation of Ultra High Temperature Ceramics in Water Vapor written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra High Temperature Ceramics (UHTCs) including HfB2 + 20v/0 SiC (HS), ZrB2 + 20v/0 SiC (ZS), and ZrB2 + 30v/0 C + 14v/0 SiC (ZCS) have been investigated for use as potential aeropropulsion engine materials. These materials were oxidized in water vapor (90 percent) using a cyclic vertical furnace at 1 atm. The total exposure time was 10 h at temperatures of 1200, 1300, and 1400 C. CVD SiC was also evaluated as a baseline for comparison. Weight change, X-ray diffraction analyses, surface and cross-sectional SEM and EDS were performed. These results are compared with tests ran in a stagnant air furnace at temperatures of 1327 C for 100 min, and with high pressure burner rig (HPBR) results at 1100 and 1300 C at 6 atm for 50 h. Low velocity water vapor does not make a significant contribution to the oxidation rates of UHTCs when compared to stagnant air. The parabolic rate constants at 1300 C, range from 0.29 to 16.0 mg(sup 2)cm(sup 4)/h for HS and ZCS, respectively, with ZS results between these two values. Comparison of results for UHTCs tested in the furnace in 90 percent water vapor with HPBR results was difficult due to significant sample loss caused by spallation in the increased velocity of the HPBR. Total recession measurements are also reported for the two test environments.
Download or read book Oxidation Resistance of Zrb2 Based Ultra High Temperature Ceramics written by Fei Peng and published by LAP Lambert Academic Publishing. This book was released on 2010-12-01 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Specimens of ZrB2 containing various concentrations of SiC, TaB2, and TaSi2 were pressureless-sintered and post-HIPed to theoretical densities. Oxidation resistances were studied by scanning thermogravimetry over the range 1150 - 1550 C, and isothermal thermogravimetry at 1200 - 1900 C. Most silicon-containing compositions formed a glassy surface layer, covering an interior oxide layer. This interior layer was less porous in tantalum-containing compositions. Small concentrations of TaB2 additions were more effective at increasing oxidation resistance than equal additions of TaSi2. The benefit of these additives was related to the formation of fine particles of ZrO2 and TaC during oxidation. These particles resisted wicking of their liquid/glassy borosilicate encapsulation. With increasing TaB2 or TaSi2 concentration, oxidation resistance degraded. In these cases, zirconia dendrites appeared to grow through the glassy layers, providing conduits for oxygen migration. At 1700 C and above, a layer of ZrB2 devoid of SiC was argued to be from preferential removal of SiC by reaction of silica oxidation product with adjacent unreacted SiC to form escaping gases.
Download or read book High Temperature Corrosion of Technical Ceramics written by R.J. Fordham and published by Springer Science & Business Media. This book was released on 1990-10-31 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Temperature Corrosion of Ceramics written by J.R. Blachere and published by William Andrew. This book was released on 1989-12-31 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The information in this book is from a 1987 Dept. of Energy report of the same title. Materials investigated in this particular study are silica, alumina, silicon nitride and silicon carbide. In addition to the pure single crystals or CVD materials, typical engineering materials of various purities are included. No index. Annotation copyrighted by Book News, Inc., Portland, OR
Download or read book MAX Phases and Ultra high Temperature Ceramics for Extreme Environments written by It-Meng Low and published by Engineering Science Reference. This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This book investigates a new class of ultra-durable ceramic materials, which exhibit characteristics of both ceramics and metals, and will explore recent advances in the manufacturing of ceramic materials that improve their durability and other physical properties, enhancing their overall usability and cost-effectiveness"--
Download or read book Ultra High Temperature Ceramics written by William G. Fahrenholtz and published by John Wiley & Sons. This book was released on 2014-10-10 with total page 601 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive book to focus on ultra-high temperature ceramic materials in more than 20 years Ultra-High Temperature Ceramics are a family of compounds that display an unusual combination of properties, including extremely high melting temperatures (>3000°C), high hardness, and good chemical stability and strength at high temperatures. Typical UHTC materials are the carbides, nitrides, and borides of transition metals, but the Group IV compounds (Ti, Zr, Hf) plus TaC are generally considered to be the main focus of research due to the superior melting temperatures and stable high-melting temperature oxide that forms in situ. Rather than focusing on the latest scientific results, Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications broadly and critically combines the historical aspects and the state-of-the-art on the processing, densification, properties, and performance of boride and carbide ceramics. In reviewing the historic studies and recent progress in the field, Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications provides: Original reviews of research conducted in the 1960s and 70s Content on electronic structure, synthesis, powder processing, densification, property measurement, and characterization of boride and carbide ceramics. Emphasis on materials for hypersonic aerospace applications such as wing leading edges and propulsion components for vehicles traveling faster than Mach 5 Information on materials used in the extreme environments associated with high speed cutting tools and nuclear power generation Contributions are based on presentations by leading research groups at the conference "Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications II" held May 13-19, 2012 in Hernstein, Austria. Bringing together disparate researchers from academia, government, and industry in a singular forum, the meeting cultivated didactic discussions and efforts between bench researchers, designers and engineers in assaying results in a broader context and moving the technology forward toward near- and long-term use. This book is useful for furnace manufacturers, aerospace manufacturers that may be pursuing hypersonic technology, researchers studying any aspect of boride and carbide ceramics, and practitioners of high-temperature structural ceramics.
Download or read book Carbon Fibres and Their Composites written by Erich Fitzer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proper choice of technology is a complex decision, particularly for developing countries, as it depends not only on local needs and conditions but also, importantly, on the national political context and, increasingly, on the international environment. This technological choice carries with it the genetic code of the nation's future development. Many developing countries which lack the needed infrastructure do not have real options; others with a reservoir of scientific and engineering skills and explicit SIT strategies, can indeed choose between alternatives. Turning to the technologies themselves, these cover a wide spectrum: traditional technologies that are low-cost, low-energy and often better suited to meet basic needs; more sophisticated technologies which are highly knowledge-intensive and require large capital outlays for research, product design and manufacturing; and still others which depend upon a blending of modern technology with traditional methods to create products and processes more suited to local needs. Even within the group of advanced technologies, there is considerable differentiation, and those at the lower end of the product cycle are clearly within reach by the newly industri alizing countries.
Download or read book Properties and Applications of Silicon Carbide written by Rosario Gerhardt and published by BoD – Books on Demand. This book was released on 2011-04-04 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, we explore an eclectic mix of articles that highlight some new potential applications of SiC and different ways to achieve specific properties. Some articles describe well-established processing methods, while others highlight phase equilibria or machining methods. A resurgence of interest in the structural arena is evident, while new ways to utilize the interesting electromagnetic properties of SiC continue to increase.
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 Additive Manufacturing written by Amit Bandyopadhyay and published by CRC Press. This book was released on 2015-09-08 with total page 547 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of additive manufacturing has seen explosive growth in recent years due largely in part to renewed interest from the manufacturing sector. Conceptually, additive manufacturing, or industrial 3D printing, is a way to build parts without using any part-specific tooling or dies from the computer-aided design (CAD) file of the part. Today, mo
Download or read book Carbide Nitride and Boride Materials Synthesis and Processing written by A.W. Weimer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 675 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbide, Nitride and Boride Materials Synthesis and Processing is a major reference text addressing methods for the synthesis of non-oxides. Each chapter has been written by an expert practising in the subject area, affiliated with industry, academia or government research, thus providing a broad perspective of information for the reader. The subject matter ranges from materials properties and applications to methods of synthesis including pre- and post-synthesis processing. Although most of the text is concerned with the synthesis of powders, chapters are included for other materials such as whiskers, platelets, fibres and coatings. Carbide, Nitride and Boride Materials Synthesis and Processing is a comprehensive overview of the subject and is suitable for practitioners in the industry as well as those looking for an introduction to the field. It will be of interest to chemical, mechanical and ceramic engineers, materials scientists and chemists in both university and industrial environments working on or with refractory carbides, nitrides and borides.
Download or read book Thermal Conductivity Database of Various Structural Carbon Carbon Composite Materials written by Craig W. Ohlhorst and published by . This book was released on 1997 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Amazon Legends and Charms Part1 written by Agnaldo Melo and published by Agnaldo Souza Melo. This book was released on 2014-11-20 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amazon legends and stories of mysterious charms portrays Amazonia showing a bit of culture and stressing the preservation of the Amazon forest.
Download or read book Advanced Structural Ceramics written by Bikramjit Basu and published by John Wiley & Sons. This book was released on 2011-10-11 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the area of advanced ceramic composites broadly, providing important introductory chapters to fundamentals, processing, and applications of advanced ceramic composites. Within each section, specific topics covered highlight the state of the art research within one of the above sections. The organization of the book is designed to provide easy understanding by students as well as professionals interested in advanced ceramic composites. The various sections discuss fundamentals of nature and characteristics of ceramics, processing of ceramics, processing and properties of toughened ceramics, high temperature ceramics, nanoceramics and nanoceramic composites, and bioceramics and biocomposites.
