Ultra High Temperature Ceramics

Ultra High Temperature Ceramics

Ultra High Temperature Ceramics

The first comprehensive book to focus on ultra-hightemperature ceramic materials in more than 20 years Ultra-High Temperature Ceramics are a family of compounds thatdisplay an unusual combination of properties, including extremelyhigh melting temperatures (>3000°C), high hardness, andgood chemical stability and strength at high temperatures. Typical UHTC materials are the carbides, nitrides, and borides oftransition metals, but the Group IV compounds (Ti, Zr, Hf) plus TaCare generally considered to be the main focus of research due tothe superior melting temperatures and stable high-meltingtemperature oxide that forms in situ. Rather than focusing on thelatest scientific results, Ultra-High Temperature Ceramics:Materials for Extreme Environment Applications broadly andcritically combines the historical aspects and the state-of-the-arton the processing, densification, properties, and performance ofboride and carbide ceramics. In reviewing the historic studies and recent progress in thefield, Ultra-High Temperature Ceramics: Materials for ExtremeEnvironment Applications provides: Original reviews of researchconducted 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 hypersonicaerospace applications such as wing leading edges and propulsioncomponents for vehicles traveling faster than Mach 5 Information on materials used in theextreme environments associated with high speed cutting tools andnuclear power generation Contributions are based on presentations by leading researchgroups at the conference "Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications II" held May 13-19,2012 in Hernstein, Austria. Bringing together disparate researchersfrom academia, government, and industry in a singular forum, themeeting cultivated didactic discussions and efforts between benchresearchers, designers and engineers in assaying results in abroader context and moving the technology forward toward near- andlong-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, andpractitioners of high-temperature structural ceramics.

Boron Rich Solids

Boron Rich Solids

Boron Rich Solids

The objective of this book is to discuss the current status of research and development of boron-rich solids as sensors, ultra-high temperature ceramics, thermoelectrics, and armor. Novel biological and chemical sensors made of stiff and light-weight boron-rich solids are very exciting and efficient for applications in medical diagnoses, environmental surveillance and the detection of pathogen and biological/chemical terrorism agents. Ultra-high temperature ceramic composites exhibit excellent oxidation and corrosion resistance for hypersonic vehicle applications. Boron-rich solids are also promising candidates for high-temperature thermoelectric conversion. Armor is another very important application of boron-rich solids, since most of them exhibit very high hardness, which makes them perfect candidates with high resistance to ballistic impact. The following topical areas are presented: •Boron-rich solids: science and technology •Synthesis and sintering strategies of boron rich solids •Microcantilever sensors •Screening of the possible boron-based thermoelectric conversion materials; •Ultra-high temperature ZrB2 and HfB2 based composites •Magnetic, transport and high-pressure properties of boron-rich solids •Restrictions of the sensor dimensions for chemical detection •Armor

MAX Phases and Ultra High Temperature Ceramics for Extreme Environments

MAX Phases and Ultra High Temperature Ceramics for Extreme Environments

MAX Phases and Ultra High Temperature Ceramics for Extreme Environments

Ceramics are a versatile material, more so than is widely known. They are thermal resistant, poor electrical conductors, insulators against nuclear radiation, and not easily damaged, making ceramics a key component in many industrial processes. MAX Phases and Ultra-High Temperature Ceramics for Extreme Environments investigates a new class of ultra-durable ceramic materials, which exhibit characteristics of both ceramics and metals. Readers 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. This book will be of primary use to researchers, academics, and practitioners in chemical, mechanical, and electrical engineering. This book is part of the Research Essentials collection.

High Temperature Ceramic Matrix Composites 8

High Temperature Ceramic Matrix Composites 8

High Temperature Ceramic Matrix Composites 8

This proceedings contains 78 papers from the 8th International Conference on High Temperature Ceramic Matrix Composites, held September 22-26, 2013 in Xi'an, Shaanxi, China. Chapters include: Ceramic Genome, Computational Modeling, and Design Advanced Ceramic Fibers, Interfaces, and Interphases Nanocomposite Materials and Systems Polymer Derived Ceramics and Composites Fiber Reinforced Ceramic MatrixComposites Carbon-Carbon Composites: Materials, Systems, and Applications Ultra High Temperature Ceramics and MAX Phase Materials Thermal and Environmental Barrier Coatings

Preparation of Ultra High Temperature Ceramics Based Materials by Sol Gel Routes

Preparation of Ultra High Temperature Ceramics Based Materials by Sol Gel Routes

Preparation of Ultra High Temperature Ceramics Based Materials by Sol Gel Routes

Ultra-high temperature ceramics (UHTCs) are a class of inorganic materials that have melting point over 3000°C and are typically borides, carbides, and nitrides of early transition metals. UHTCs are considered as the promising candidate used in the extreme environment involved with the hypersonic aviation thermal protective system. Synthesis of UHTC-based materials can be divided into solid-based and solution-based protocols according to the state of the raw materials. A sol-gel technique is one of the solution-based protocols for the preparation of UHTC-based materials, which involves the hydrolysis, condensation of the metal organic and/or metal inorganic compounds, gelation, and the posthigh temperature treatment of the dried gels. The sol-gel technique enables the synthesis of UHTC-based materials at 1300-1600°C. UHTC-based materials with desired shapes, such as nanopowders, fibers, and porous monoliths, can also be prepared via sol-gel routes.

Advances in High Temperature Ceramic Matrix Composites and Materials for Sustainable Development

Advances in High Temperature Ceramic Matrix Composites and Materials for Sustainable Development

Advances in High Temperature Ceramic Matrix Composites and Materials for Sustainable Development

Global population growth and tremendous economic development has brought us to the crossroads of long-term sustainability and risk of irreversible changes in the ecosystem. Energy efficient and ecofriendly technologies and systems are critically needed for further growth and sustainable development. While ceramic matrix composites were originally developed to overcome problems associated with the brittle nature of monolithic ceramics, today the composites can be tailored for customized purposes and offer energy efficient and ecofriendly applications, including aerospace, ground transportation, and power generation systems. The 9th International Conference on High Temperature Ceramic Matrix Composites (HTCMC 9) was held in Toronto, Canada, June 26-30, 2016 to discuss challenges and opportunities in manufacturing, commercialization, and applications for these important material systems. The Global Forum on Advanced Materials and Technologies for Sustainable Development (GFMAT 2016) was held in conjunction with HTCMC 9 to address key issues, challenges, and opportunities in a variety of advanced materials and technologies that are critically needed for sustainable societal development. This Ceramic Transactions volume contains a collection of peer reviewed papers from the 16 below symposia that were submitted from these two conferences Design and Development of Advanced Ceramic Fibers, Interfaces, and Interphases in Composites- A Symposium in Honor of Professor Roger Naslain Innovative Design, Advanced Processing, and Manufacturing Technologies Materials for Extreme Environments: Ultrahigh Temperature Ceramics (UHTCs) and Nano-laminated Ternary Carbides and Nitrides (MAX Phases) Polymer Derived Ceramics and Composites Advanced Thermal and Environmental Barrier Coatings: Processing, Properties, and Applications Thermomechanical Behavior and Performance of Composites Ceramic Integration and Additive Manufacturing Technologies Component Testing and Evaluation of Composites CMC Applications in Transportation and Industrial Systems Powder Processing Innovation and Technologies for Advanced Materials and Sustainable Development Novel, Green, and Strategic Processing and Manufacturing Technologies Ceramics for Sustainable Infrastructure: Geopolymers and Sustainable Composites Advanced Materials, Technologies, and Devices for Electro-optical and Medical Applications Porous Ceramics for Advanced Applications Through Innovative Processing Multifunctional Coatings for Sustainable Energy and Environmental Applications

Ultra High Temperature Materials II

Ultra High Temperature Materials II

Ultra High Temperature Materials II

This exhaustive work in three volumes and over 1300 pages provides a thorough treatment of ultra-high temperature materials with melting points over 2500 °C. The first volume focuses on Carbon and Refractory Metals, whilst the second and third are dedicated solely to Refractory compounds and the third to Refractory Alloys and Composites respectively. 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 of carbon (graphite/graphene), refractory metals (W, Re, Os, Ta, Mo, Nb, Ir) and compounds (oxides, nitrides, carbides, borides, silicides) with melting points in this range. It will be of interest to researchers, engineers, postgraduate, graduate and undergraduate students 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 and engineering.

Ultra High Temperature Materials III

Ultra High Temperature Materials III

Ultra High Temperature Materials III

This exhaustive work in several volumes and over 2500 pages provides a thorough treatment of ultra-high temperature materials (with melting points around or over 2500 °C). The first volume focuses on carbon (graphene/graphite) and refractory metals (W, Re, Os, Ta, Mo, Nb and Ir), whilst the second and third are dedicated to refractory transition metal 4-5 groups carbides. Topics included are physical (structural, thermal, electro-magnetic, optical, mechanical, nuclear) and chemical (more than 3000 binary, ternary and multi-component systems, including those used for materials design, data on solid-state diffusion, wettability, interaction with various elements and compounds in solid and liquid states, gases and chemicals in aqueous solutions) properties of these materials. It will be of interest to researchers, engineers, postgraduate, graduate and undergraduate students alike. The readers/users are provided with the full qualitative and quantitative assessment, which is based on the latest updates in the field of fundamental physics and chemistry, nanotechnology, materials science, design and engineering.

Synthesis of Dual Phase High Entropy Ultrahigh Temperature Ceramics and Reactive Sintering of Boride Based High Entropy Ceramics

Synthesis of Dual Phase High Entropy Ultrahigh Temperature Ceramics and Reactive Sintering of Boride Based High Entropy Ceramics

Synthesis of Dual Phase High Entropy Ultrahigh Temperature Ceramics and Reactive Sintering of Boride Based High Entropy Ceramics

The everlasting demands of new materials to fulfill certain functional or structural applications stimulate the exploration and innovation of materials science. As a brand new field in material development, high-entropy materials have received great amounts of research effort in the past decade. In the community of metallurgy, high-entropy alloys are widely reported to possess excellent physical and mechanical properties beyond each of their individual components. As ceramics counterparts to high-entropy alloys, high-entropy ceramics present another big family in high-entropy materials and have attracted increased attention since their inception in 2015. Over the past few years, numerous amounts of high-entropy ceramics of different kinds have been synthesized and characterized; and various fabrication routes have been developed and analyzed. Despite all these achievements, high-entropy ceramics is still a fledging topic with plenty of opportunities and challenges. In this dissertation, bulk synthesis and densification of dual-phase high-entropy ultrahigh temperature ceramics and four classes of high-entropy borides of different structures are investigated. First, a new series dual-phase high-entropy boride and carbide ultrahigh temperature ceramics are fabricated to full density in bulk pellets. Binary borides and carbides are utilized as the precursors. Extra addition of graphite and prolong holdings at elevated temperatures during sintering facilitate the removal of intrinsic oxides. The sintered dual-phase specimens are demonstrated to possess tunable microstructures and properties, as well as higher hardness than the average of single-phase high-entropy components. Then, three classes of refractory metal high-entropy borides, each with prototype of Ta3B4, CrB, or AlB2, are synthesized via in-situ reactive spark plasma sintering of ball-milled elemental powders; and all sintered specimens are close to fully dense without measurable oxides. W-containing high-entropy diborides from elemental precursors are fabricated to be single-phase, which is not alternatively achievable from binary boride precursors; and somewhat unexpectedly, these W-containing high-entropy diborides are measured to possess higher hardness, although WB2 are predicted to have lower hardness than other refractory metal diborides. On the other hand, high-entropy monoborides represent a promising series towards superhard materials, with composition (V0.2Cr0.2Nb0.2Ta0.2W0.2)B demonstrated to be harder than the reported superhard ternary monoboride solid solutions. The final part of the dissertation focuses on the rare earth high-entropy borides; and a novel class of high-entropy tetraborides with UB4-typed tetragonal structure has been successfully developed. The homogenous elemental distributions in the sintered specimen have been verified by both micro-scale SEM and nano-scale TEM characterizations. These high-entropy tetraboride represent the first equimolar highentropy ceramics in tetragonal structure. The production of these novel high-entropy materials further expands the scope of high-entropy ceramics; and the fabrication route of reactive sintering from elemental precursors facilitates the synthesis of other high-entropy materials at different cation-anion ratios. The successful synthesis of these new materials provides another platform for composition adjustment and property tailoring.

Processing for Improved Creep Behavior of Ultra high Temperature Ceramics

Processing for Improved Creep Behavior of Ultra high Temperature Ceramics

Processing for Improved Creep Behavior of Ultra high Temperature Ceramics

Ultra-high temperature ceramics have been considered for several extreme applications involving high temperatures and oxidizing atmospheres. Most notably, sharp leading edges and nosecones associated with hypersonic re-entry vehicles often benefit from advanced material performance under long exposure to severe conditions. ZrB2-based composites consistently compete with the other candidates for these applications due to their high melting temperatures (exceeding 3000°C), high temperature strength retention and good oxidation resistance. Long duty cycle aerospace applications particularly necessitate excellent creep deformation resistance reaching or exceeding 10-8s-1 in steady state creep rates. In the present work, ZrB2-SiC composite and ZrB2-WC alloy were selected for creep testing at 1800°C in protected environments. Two sets of experiments were performed on the hot pressed composite: four-point flexure tests at 16 and 20 MPa and compression tests under stresses ranging between 10 and 40 MPa. The data fit well to power law creep models (Norton) and based on four-point bend data, uniaxial creep parameters were determined using an analytical method present in the literature. Predicted and experimental compressive stress exponents were found to be in excellent agreement, 1.85 and 1.76 respectively. Stress exponent supported by observation of the microstructure suggest a combination of diffusion and grain boundary sliding creep mechanisms in compression. In tension, a stress exponent of 2.61, exceeds the flexural stress exponent of 2.2, suggesting an increased contribution from cavitation to the creep strain, contrasting with grain boundary sliding observed as the predominate creep mechanism for flexural creep at this temperature. Earlier work has shown the importance of grain boundary sliding on the creep deformation of ZrB2 at 1800°C, and also that this mechanism relies upon a critical accommodation mechanism involving dislocation activity in the grain boundary region. Therefore, the effect of WC addition on the creep behavior of ZrB2 was investigated in the context of a solute-dislocation interaction hypothesis in efforts to impede the accommodation event and thus retard the creep deformation. Four-point flexure experiments showed two orders of magnitude reduction in creep rates in the ZrB2-WC alloy compared to ZrB2-SiC composite when ~1.5 mol% of W dissolved in ZrB2 lattice. Additionally, a stress exponent drop from ~2.2 in ZrB2-SiC to ~1.2 in ZrB2-WC suggests transition from climb to glide controlled deformation accommodation due to effective solute interactions with gliding dislocations. The solubility of W in ZrB2 is not well known and was estimated here through two methods. First, experimentally, where ZrB2 was successfully densified by pressureless sintering to near full density at temperatures as low as 1850°C, with the addition of B4C as sintering additive. An experimental phase diagram was approximated as the samples were produced. Second, using a combination of density functional theory simulations and thermodynamic modeling based on a sublattice description of the solid solution phase. The calculated solvus line suggests no solubility of W in ZrB2 below ~1380°C and reduced solubility in the presence of C at higher temperatures.