Oxidation and Catalytic Efficiency of ZrB2 and HfB2 Based Ultra-high-temperature Ceramic (UHTC) Composites Exposed to Supersonic Air Plasma PDF Download
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Author: Jochen Marschall
Publisher:
ISBN:
Category :
Languages : en
Pages : 48
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Book Description
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.
Author: Jochen Marschall
Publisher:
ISBN:
Category :
Languages : en
Pages : 48
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Book Description
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.
Author: Dileep Singh
Publisher: John Wiley & Sons
ISBN: 0470584254
Category : Technology & Engineering
Languages : en
Pages : 350
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Book Description
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.
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721650033
Category :
Languages : en
Pages : 34
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Book Description
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
Author: Nasa Technical Reports Server (Ntrs)
Publisher: BiblioGov
ISBN: 9781289263522
Category :
Languages : en
Pages : 24
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Book Description
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.
Author: Fei Peng
Publisher: LAP Lambert Academic Publishing
ISBN: 9783843379892
Category :
Languages : en
Pages : 112
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Book Description
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.
Author: R.J. Fordham
Publisher: Springer Science & Business Media
ISBN: 9781851665686
Category : Technology & Engineering
Languages : en
Pages : 244
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Book Description
Author: J.R. Blachere
Publisher: William Andrew
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 208
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Book Description
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
Author: It-Meng Low
Publisher: Engineering Science Reference
ISBN: 9781466640665
Category : Ceramic-matrix composites
Languages : en
Pages : 0
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Book Description
"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"--
Author: William G. Fahrenholtz
Publisher: John Wiley & Sons
ISBN: 111892441X
Category : Technology & Engineering
Languages : en
Pages : 601
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Book Description
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.
Author: Rosario Gerhardt
Publisher: BoD – Books on Demand
ISBN: 9533072016
Category : Science
Languages : en
Pages : 550
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Book Description
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.
