Oxidation Resistance of Zrb2 Based Ultra-High Temperature Ceramics PDF Download
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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: 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: 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: Xinghong Zhang
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659533440
Category : Ceramic-matrix composites
Languages : en
Pages : 156
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Book Description
Several diborides, carbides and nitrides of the group IVB and VB transition metals are a family of materials known as ultrahigh temperature ceramics based on melting temperatures in excess of 3000 C. In recent years, hafnium and zirconium borides in ultrahigh temperature ceramics have attracted increasing attention from material scientists and engineers due to their unique combination of high melting point, high strength, high electrical and thermal conductivities, excellent corrosion resistance, and good oxidation resistance. These properties make the ultrahigh temperature ceramics promising candidates for high-temperature applications, including thermal protective structures for leading-edge parts on hypersonic re-entry space vehicles, propulsion systems, furnace elements, refractory crucibles, and plasma-arc electrodes.
Author: Richard Philip Stadelmann
Publisher:
ISBN:
Category :
Languages : en
Pages : 245
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Book Description
In the present research the ZrB2-17vol%SiC, ZrB2-32vol%SiC, and ZrB2-45vol%SiC ultra-high temperature particulate ceramic composites were sintered using both Hot Pressing (HP) and Spark Plasma Sintering (SPS) techniques. The mechanical performance of the ZrB2-SiC composites was investigated using 3- and 4-point bending techniques for measurements of instantaneous fracture strength and fracture toughness. Resonant Ultrasound Spectroscopy was used for measurement of Young's, shear, and bulk moduli as well as Poisson's ratio of the composites. The distribution of thermal residual stresses and the effect of the applied external load on their re-distribution was studied using micro-Raman spectroscopy. Piezospectroscopic coefficients were determined for all compositions of ZrB2-SiC ceramic under study and their experimentally obtained values were compared with the piezospectroscopic coefficients both published in the literature and calculated using theoretical approach. Finally, the novel ZrB2-IrB2-SiC ceramic composites were also produced using Spark Plasma Sintering (SPS), where IrB2 powder was synthesized using mechanochemical route. It is expected that the IrB2 additive phase might contribute to the improved overall oxidation resistance of ZrB2 based ultra-high temperature ceramic composites.
Author: Dipankar Ghosh
Publisher: Elsevier Inc. Chapters
ISBN: 0128057165
Category : Technology & Engineering
Languages : en
Pages : 75
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Book Description
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: Adam Lee Chamberlain
Publisher:
ISBN:
Category : Borides
Languages : en
Pages : 324
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Book Description
"Research into ultra high temperature materials has increased in recent years due to the need for material systems that can withstand the temperatures associated with hypersonic flight applications. ZrB2 and HfB2 are among the candidates for these extreme conditions. These diborides have melting temperatures that exceed 3000°C, the potential for strength retention at elevated temperatures, and moderate oxidation resistance when compared to high temperature carbides. However, diborides have often been reported to exhibit low strength and significant strength degradation by 1500°C; therefore, limiting their use at high temperatures ... This research focused on processing zirconium diboride (ZrB2) ceramics that exhibit improved mechanical performance and reduced impurity content. Three processing methods have been used to produce dense ZrB2 ceramics; conventional hot pressing, reactive hot pressing, and pressureless sintering"--Abstract, leaf iv.
Author: Electrochemical Society. High Temperature Materials Division
Publisher: The Electrochemical Society
ISBN: 9781566773188
Category : Science
Languages : en
Pages : 380
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Book Description
Author: Narottam P. Bansal
Publisher: Springer Science & Business Media
ISBN: 0387239863
Category : Technology & Engineering
Languages : en
Pages : 547
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Book Description
This valuable handbook has been compiled by internationally renowned researchers in the field. Each chapter is focused on a specific composite system or a class of composites, presenting a detailed description of processing, properties, and applications.
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.
