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Sample records for advanced ceramic components

  1. Advances in resonance based NDT for ceramic components

    NASA Astrophysics Data System (ADS)

    Hunter, L. J.; Jauriqui, L. M.; Gatewood, G. D.; Sisneros, R.

    2012-05-01

    The application of resonance based non-destructive testing methods has been providing benefit to manufacturers of metal components in the automotive and aerospace industries for many years. Recent developments in resonance based technologies are now allowing the application of resonance NDT to ceramic components including turbine engine components, armor, and hybrid bearing rolling elements. Application of higher frequencies and advanced signal interpretation are now allowing Process Compensated Resonance Testing to detect both internal material defects and surface breaking cracks in a variety of ceramic components. Resonance techniques can also be applied to determine material properties of coupons and to evaluate process capability for new manufacturing methods.

  2. Development of sensors for ceramic components in advanced propulsion systems

    NASA Technical Reports Server (NTRS)

    Atkinson, William H.; Cyr, M. A.; Strange, R. R.

    1994-01-01

    The 'Development of Sensors for Ceramics Components in Advanced Propulsion Systems' program was divided into two phases. The objectives of Phase 1 were to analyze, evaluate and recommend sensor concepts for the measurement of surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. The results of this effort were previously published in NASA CR-182111. As a result of Phase 1, three approaches were recommended for further development: pyrometry, thin-film sensors, and thermographic phosphors. The objectives of Phase 2 were to fabricate and conduct laboratory demonstration tests of these systems. A summary report of the Phase 2 effort, together with conclusions and recommendations for each of the categories evaluated, has been submitted to NASA. Emittance tests were performed on six materials furnished by NASA Lewis Research Center. Measurements were made of various surfaces at high temperature using a Thermogage emissometer. This report describes the emittance test program and presents a summary of the results.

  3. Advanced Gas Turbine (AGT) Technology Development Project, ceramic component developments

    NASA Technical Reports Server (NTRS)

    Teneyck, M. O.; Macbeth, J. W.; Sweeting, T. B.

    1987-01-01

    The ceramic component technology development activity conducted by Standard Oil Engineered Materials Company while performing as a principal subcontractor to the Garrett Auxiliary Power Division for the Advanced Gas Turbine (AGT) Technology Development Project (NASA Contract DEN3-167) is summarized. The report covers the period October 1979 through July 1987, and includes information concerning ceramic technology work categorized as common and unique. The former pertains to ceramic development applicable to two parallel AGT projects established by NASA contracts DEN3-168 (AGT100) and DEN3-167 (AGT101), whereas the unique work solely pertains to Garrett directed activity under the latter contract. The AGT101 Technology Development Project is sponsored by DOE and administered by NASA-Lewis. Standard Oil directed its efforts toward the development of ceramic materials in the silicon-carbide family. Various shape forming and fabrication methods, and nondestructive evaluation techniques were explored to produce the static structural components for the ceramic engine. This permitted engine testing to proceed without program slippage.

  4. Sensors for ceramic components in advanced propulsion systems

    NASA Technical Reports Server (NTRS)

    Koller, A. C.; Bennethum, W. H.; Burkholder, S. D.; Brackett, R. R.; Harris, J. P.

    1995-01-01

    This report includes: (1) a survey of the current methods for the measurement of surface temperature of ceramic materials suitable for use as hot section flowpath components in aircraft gas turbine engines; (2) analysis and selection of three sensing techniques with potential to extend surface temperature measurement capability beyond current limits; and (3) design, manufacture, and evaluation of the three selected techniques which include the following: platinum rhodium thin film thermocouple on alumina and mullite substrates; doped silicon carbide thin film thermocouple on silicon carbide, silicon nitride, and aluminum nitride substrates; and long and short wavelength radiation pyrometry on the substrates listed above plus yttria stabilized zirconia. Measurement of surface emittance of these materials at elevated temperature was included as part of this effort.

  5. Standardization Efforts for Mechanical Testing and Design of Advanced Ceramic Materials and Components

    NASA Technical Reports Server (NTRS)

    Salem, Jonathan A.; Jenkins, Michael G.

    2003-01-01

    Advanced aerospace systems occasionally require the use of very brittle materials such as sapphire and ultra-high temperature ceramics. Although great progress has been made in the development of methods and standards for machining, testing and design of component from these materials, additional development and dissemination of standard practices is needed. ASTM Committee C28 on Advanced Ceramics and ISO TC 206 have taken a lead role in the standardization of testing for ceramics, and recent efforts and needs in standards development by Committee C28 on Advanced Ceramics will be summarized. In some cases, the engineers, etc. involved are unaware of the latest developments, and traditional approaches applicable to other material systems are applied. Two examples of flight hardware failures that might have been prevented via education and standardization will be presented.

  6. Advanced Environmental Barrier Coating Development for SiC-SiC Ceramic Matrix Composite Components

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Harder, Bryan; Bhatt, Ramakrishna; Kiser, Doug; Wiesner, Valerie L.

    2016-01-01

    This presentation reviews the NASA advanced environmental barrier coating (EBC) system development for SiCSiC Ceramic Matrix Composite (CMC) components for next generation turbine engines. The emphasis has been placed on the current design challenges of the 2700F environmental barrier coatings; coating processing and integration with SiCSiC CMCs and component systems; and performance evaluation and demonstration of EBC-CMC systems. This presentation also highlights the EBC-CMC system temperature capability and durability improvements through advanced compositions and architecture designs, as shown in recent simulated engine high heat flux, combustion environment, in conjunction with mechanical creep and fatigue loading testing conditions.

  7. Development of Sensors for Ceramic Components in Advanced Propulsion Systems. Phase 2; Temperature Sensor Systems Evaluation

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1994-01-01

    The 'development of sensors for ceramic components in advanced propulsion systems' program is divided into two phases. The objectives of Phase 1 were to analyze, evaluate and recommend sensor concepts for the measurement of surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. The results of this effort were previously published in NASA CR-182111. As a result of Phase 1, three approaches were recommended for further development: pyrometry, thin-film sensors, and thermographic phosphors. The objective of Phase 2 were to fabricate and conduct laboratory demonstration tests of these systems. Six materials, mutually agreed upon by NASA and Pratt & Whitney, were investigated under this program. This report summarizes the Phase 2 effort and provides conclusions and recommendations for each of the categories evaluated.

  8. Advanced SiC/SiC Ceramic Composites For Gas-Turbine Engine Components

    NASA Technical Reports Server (NTRS)

    Yun, H. M.; DiCarlo, J. A.; Easler, T. E.

    2004-01-01

    NASA Glenn Research Center (GRC) is developing a variety of advanced SiC/SiC ceramic composite (ASC) systems that allow these materials to operate for hundreds of hours under stress in air at temperatures approaching 2700 F. These SiC/SiC composite systems are lightweight (approximately 30% metal density) and, in comparison to monolithic ceramics and carbon fiber-reinforced ceramic composites, are able to reliably retain their structural properties for long times under aggressive gas-turbine engine environments. The key for the ASC systems is related first to the NASA development of the Sylramic-iBN Sic fiber, which displays higher thermal stability than any other SiC- based ceramic fibers and possesses an in-situ grown BN surface layer for higher environmental durability. This fiber is simply derived from Sylramic Sic fiber type that is currently produced at ATK COI Ceramics (COIC). Further capability is then derived by using chemical vapor infiltration (CVI) and/or polymer infiltration and pyrolysis (PIP) to form a Sic-based matrix with high creep and rupture resistance as well as high thermal conductivity. The objectives of this study were (1) to optimize the constituents and processing parameters for a Sylramic-iBN fiber reinforced ceramic composite system in which the Sic-based matrix is formed at COIC almost entirely by PIP (full PIP approach), (2) to evaluate the properties of this system in comparison to other 2700 F Sylramic-iBN systems in which the matrix is formed by full CVI and CVI + PIP, and (3) to examine the pros and cons of the full PIP approach for fabricating hot-section engine components. A key goal is the development of a composite system with low porosity, thereby providing high modulus, high matrix cracking strength, high interlaminar strength, and high thermal conductivity, a major property requirement for engine components that will experience high thermal gradients during service. Other key composite property goals are demonstration at

  9. Life prediction methodology for ceramic components of advanced heat engines. Phase 1: Volume 1, Final report

    SciTech Connect

    Cuccio, J.C.; Brehm, P.; Fang, H.T.

    1995-03-01

    Emphasis of this program is to develop and demonstrate ceramics life prediction methods, including fast fracture, stress rupture, creep, oxidation, and nondestructive evaluation. Significant advancements were made in these methods and their predictive capabilities successfully demonstrated.

  10. Life prediction methodology for ceramic components of advanced heat engines. Phase 1: Volume 2, Appendices

    SciTech Connect

    1995-03-01

    This volume presents the following appendices: ceramic test specimen drawings and schematics, mixed-mode and biaxial stress fracture of structural ceramics for advanced vehicular heat engines (U. Utah), mode I/mode II fracture toughness and tension/torsion fracture strength of NT154 Si nitride (Brown U.), summary of strength test results and fractography, fractography photographs, derivations of statistical models, Weibull strength plots for fast fracture test specimens, and size functions.

  11. Advanced Ceramic Armor Materials

    DTIC Science & Technology

    1990-05-11

    materials, toughened alumina, fiber -reinforced glass matrix composites, and multilayer-gradient materials for ballistic testing. Fabrication and...material systems: Multilayer advanced armor materials consisting of a hard ceramic faceplate bonded to a graphite fiber -reinforced glass matrix...toughened alumina, and fiber - applied studies of advanced reinforced ceramic matrix glass and glass -ceramic composites for ballistic testing. technologies

  12. Development of sensors for ceramic components in advanced propulsion systems: Survey and evaluation of measurement techniques for temperature, strain and heat flux for ceramic components in advanced propulsion systems

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1988-01-01

    The report presents the final results of Tasks 1 and 2, Development of Sensors for Ceramic Components in Advanced Propulsion Systems (NASA program NAS3-25141). During Task 1, an extensive survey was conducted of sensor concepts which have the potential for measuring surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. Each sensor concept was analyzed and evaluated under Task 2; sensor concepts were then recommended for further development. For temperature measurement, both pyrometry and thermographic phosphors are recommended for measurements up to and beyond the melting point of ceramic materials. For lower temperature test programs, the thin-film techniques offer advantages in the installation of temperature sensors. Optical strain measurement techniques are recommended because they offer the possibility of being useful at very high temperature levels. Techniques for the measurement of heat flux are recommended for development based on both a surface mounted sensor and the measurement of the temperature differential across a portion of a ceramic component or metallic substrate.

  13. Ceramic component for electrodes

    DOEpatents

    Marchant, David D.

    1979-01-01

    A ceramic component suitable for preparing MHD generator electrodes consists of HfO.sub.2 and sufficient Tb.sub.4 O.sub.7 to stabilize at least 60 volume percent of the HfO.sub.2 into the cubic structure. The ceramic component may also contain a small amount of PrO.sub.2, Yb.sub.2 O.sub.3 or a mixture of both to improve stability and electronic conductivity of the electrode. The component is highly resistant to corrosion by molten potassium seed and molten coal slag in the MHD fluid and exhibits both ionic and electronic conductivity.

  14. Next generation grinding spindle for cost-effective manufacture of advanced ceramic components

    SciTech Connect

    Kovach, J.A.; Laurich, M.A.

    2000-01-01

    Finish grinding of advanced structural ceramics has generally been considered an extremely slow and costly process. Recently, however, results from the High-Speed, Low-Damage (HSLD) program have clearly demonstrated that numerous finish-process performance benefits can be realized by grinding silicon nitride at high wheel speeds. A new, single-step, roughing-process capable of producing high-quality silicon nitride parts at high material removal rates while dramatically reducing finishing costs has been developed.

  15. Life prediction methodology for ceramic components of advanced vehicular heat engines: Volume 1. Final report

    SciTech Connect

    Khandelwal, P.K.; Provenzano, N.J.; Schneider, W.E.

    1996-02-01

    One of the major challenges involved in the use of ceramic materials is ensuring adequate strength and durability. This activity has developed methodology which can be used during the design phase to predict the structural behavior of ceramic components. The effort involved the characterization of injection molded and hot isostatic pressed (HIPed) PY-6 silicon nitride, the development of nondestructive evaluation (NDE) technology, and the development of analytical life prediction methodology. Four failure modes are addressed: fast fracture, slow crack growth, creep, and oxidation. The techniques deal with failures initiating at the surface as well as internal to the component. The life prediction methodology for fast fracture and slow crack growth have been verified using a variety of confirmatory tests. The verification tests were conducted at room and elevated temperatures up to a maximum of 1371 {degrees}C. The tests involved (1) flat circular disks subjected to bending stresses and (2) high speed rotating spin disks. Reasonable correlation was achieved for a variety of test conditions and failure mechanisms. The predictions associated with surface failures proved to be optimistic, requiring re-evaluation of the components` initial fast fracture strengths. Correlation was achieved for the spin disks which failed in fast fracture from internal flaws. Time dependent elevated temperature slow crack growth spin disk failures were also successfully predicted.

  16. Ceramic component for electrodes

    DOEpatents

    Marchant, David D.; Bates, J. Lambert

    1980-01-01

    A ceramic component suitable for preparing MHD generator electrodes having the compositional formula: Y.sub.x (Mg.sub.y Cr.sub.z).sub.w Al.sub.(1-w) O.sub.3 where x=0.9 to 1.05, y=0.02 to 0.2, z=0.8 to 1.05 and w=1.0 to 0.5. The component is resistant to the formation of hydration products in an MHD environment, has good electrical conductivity and exhibits a lower electrochemical corrosion rate than do comparable compositions of lanthanum chromite.

  17. Advanced ceramics for environmental protection

    SciTech Connect

    Chambers, J.A.

    1994-12-31

    Advanced ceramic materials offer significant thermodynamic efficiency advantages over metals and alloys because of their higher use temperatures. Using ceramic components results in higher temperature industrial processes which convert fuels to energy more efficiently, reducing environmental emissions. Ceramics have always offered high temperature strength and superior corrosion and erosion resistance. However, brittleness, poor thermal stock resistance and catastrophic failure have slowed industrial adoptions of ceramics in environmental applications. This paper will focus on environmental applications of three new advanced ceramic materials that are overcoming these barriers to industrial utilization through improved toughness, reliability, and thermal shock performance. PRD-66, a layered oxide ceramic with outstanding thermal shock resistance and high use temperature with utility in catalyst support, insulation, and hot gas filtration applications, is discussed. Tough silicon carbide fiber reinforced silicon carbide (SiC/SiC) and carbon fiber reinforced silicon carbide (C/SiC) ceramic composites made by chemical vapor infiltration, and silicon carbide particulate reinforced alumina (SiC{sub p}/Al{sub 2}O{sub 3}) composites made through Lanxide Corporation`s DIMOX{trademark} directed metal oxidation process are described. Applications of these materials to pollution reduction and energy efficiency in medical and municipal waste incineration, heat management, aluminum remelting, pyrolysis, coal combustion and gasification, catalytic pollution control, and hot gas filtration, will be discussed.

  18. Advanced Ceramics Property Measurements

    NASA Technical Reports Server (NTRS)

    Salem, Jonathan; Helfinstine, John; Quinn, George; Gonczy, Stephen

    2013-01-01

    Mechanical and physical properties of ceramic bodies can be difficult to measure correctly unless the proper techniques are used. The Advanced Ceramics Committee of ASTM, C-28, has developed dozens of consensus test standards and practices to measure various properties of a ceramic monolith, composite, or coating. The standards give the "what, how, how not, and why" for measurement of many mechanical, physical, thermal, and performance properties. Using these standards will provide accurate, reliable, and complete data for rigorous comparisons with other test results from your test lab, or another. The C-28 Committee has involved academics, producers, and users of ceramics to write and continually update more than 45 standards since the committee's inception in 1986. Included in this poster is a pictogram of the C-28 standards and information on how to obtain individual copies with full details or the complete collection of standards in one volume.

  19. Ceramic Technology for Advanced Heat Engines Project

    SciTech Connect

    Not Available

    1990-08-01

    The Ceramic Technology For Advanced Heat Engines Project was developed by the Department of Energy's Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Advanced Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the Department of Energy (DOE), National Aeronautics and Space Administration (NASA), and Department of Defense (DOD) advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a five year project plan was developed with extensive input from private industry. The objective of the project is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on structural ceramics for advanced gas turbine and diesel engines, ceramic hearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines.

  20. Failure Analysis of Ceramic Components

    SciTech Connect

    B.W. Morris

    2000-06-29

    Ceramics are being considered for a wide range of structural applications due to their low density and their ability to retain strength at high temperatures. The inherent brittleness of monolithic ceramics requires a departure from the deterministic design philosophy utilized to analyze metallic structural components. The design program ''Ceramic Analysis and Reliability Evaluation of Structures Life'' (CARES/LIFE) developed by NASA Lewis Research Center uses a probabilistic approach to predict the reliability of monolithic components under operational loading. The objective of this study was to develop an understanding of the theories used by CARES/LIFE to predict the reliability of ceramic components and to assess the ability of CARES/LIFE to accurately predict the fast fracture behavior of monolithic ceramic components. A finite element analysis was performed to determine the temperature and stress distribution of a silicon carbide O-ring under diametral compression. The results of the finite element analysis were supplied as input into CARES/LIFE to determine the fast fracture reliability of the O-ring. Statistical material strength parameters were calculated from four-point flexure bar test data. The predicted reliability showed excellent correlation with O-ring compression test data indicating that the CARES/LIFE program can be used to predict the reliability of ceramic components subjected to complicated stress states using material properties determined from simple uniaxial tensile tests.

  1. Ceramic technology for Advanced Heat Engines Project

    SciTech Connect

    Johnson, D.R.

    1991-07-01

    Significant accomplishments in fabricating ceramic components for advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and database and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a five year project plan was developed with extensive input from private industry. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. This project is managed by ORNL for the Office of Transportation Technologies, Office of Transportation Materials, and is closely coordinated with complementary ceramics tasks funded by other DOE offices, NASA, DOD, and industry.

  2. Ceramic component for MHD electrode

    DOEpatents

    Marchant, David D.; Bates, Junior L.

    1981-01-01

    A ceramic component which exhibits electrical conductivity down to near room temperatures has the formula: Hf.sub.x In.sub.y A.sub.z O.sub.2 where x=0.1 to 0.4, y=0.3 to 0.6, z=0.1 to 0.4 and A is a lanthanide rare earth or yttrium. The component is suitable for use in the fabrication of MHD electrodes or as the current leadout portion of a composite electrode with other ceramic components.

  3. Ceramic components for MHD electrode

    DOEpatents

    Marchant, D.D.

    A ceramic component which exhibits electrical conductivity down to near room temperatures has the formula: Hf/sub x/In/sub y/A/sub z/O/sub 2/ where x = 0.1 to 0.4, y = 0.3 to 0.6, z = 0.1 to 0.4 and A is a lanthanide rare earth or yttrium. The component is suitable for use in the fabrication of MHD electrodes or as the current leadout portion of a composite electrode with other ceramic components.

  4. Ceramic superconducting components

    NASA Technical Reports Server (NTRS)

    Haertling, G. H.

    1991-01-01

    An approach to the application of high-Tc ceramic superconductors to practical circuit elements was developed and demonstrated. This method, known as the rigid conductor process (RCP), involves the mounting of a preformed, sintered, and tested superconductor material onto an appropriate, rigid substrate with an epoxy adhesive which also serves to encapsulate the element from the ambient environment. Circuit elements such as straight conductors, coils and connectors were fabricated from YBa2Cu3O(7-x) superconducting material. Performance results are included for a low-noise low-thermal-conductivity superconducting grounding link for NASA.

  5. Development of Advanced Ceramic Manufacturing Technology

    SciTech Connect

    Pujari, V.K.

    2001-04-05

    Advanced structural ceramics are enabling materials for new transportation engine systems that have the potential for significantly reducing energy consumption and pollution in automobiles and heavy vehicles. Ceramic component reliability and performance have been demonstrated in previous U.S. DOE initiatives, but high manufacturing cost was recognized as a major barrier to commercialization. Norton Advanced Ceramics (NAC), a division of Saint-Gobain Industrial Ceramics, Inc. (SGIC), was selected to perform a major Advanced Ceramics Manufacturing Technology (ACMT) Program. The overall objectives of NAC's program were to design, develop, and demonstrate advanced manufacturing technology for the production of ceramic exhaust valves for diesel engines. The specific objectives were (1) to reduce the manufacturing cost by an order of magnitude, (2) to develop and demonstrate process capability and reproducibility, and (3) to validate ceramic valve performance, durability, and reliability. The program was divided into four major tasks: Component Design and Specification, Component Manufacturing Technology Development, Inspection and Testing, and Process Demonstration. A high-power diesel engine valve for the DDC Series 149 engine was chosen as the demonstration part for this program. This was determined to be an ideal component type to demonstrate cost-effective process enhancements, the beneficial impact of advanced ceramics on transportation systems, and near-term commercialization potential. The baseline valve material was NAC's NT451 SiAION. It was replaced, later in the program, by an alternate silicon nitride composition (NT551), which utilized a lower cost raw material and a simplified powder-processing approach. The material specifications were defined based on DDC's engine requirements, and the initial and final component design tasks were completed.

  6. Cost effective machining and inspection of structural ceramic components for advanced high temperature application. Final CRADA report for CRADA number Y-1292-0151

    SciTech Connect

    Abbatiello, L.A.; Haselkorn, M.

    1996-11-29

    This Cooperative Research and Development Agreement (CRADA) was a mutual research and development (R and D) effort among the participants to investigate a range of advanced manufacturing technologies for two silicon nitride (Si{sub 3}N{sub 4}) ceramic materials. The general objective was to identify the most cost-effective part manufacturing processes for the ceramic materials of interest. The focus was determining the relationship between material removal rates, surface quality, and the structural characteristics of each ceramic resulting from three innovative processes. These innovated machining processes were studied using silicon nitride advanced materials. The particular (Si{sub 3}N{sub 4}) materials of interest were sintered GS-44 from the Norton Company, and reaction-bonded Ceraloy 147-3. The processes studied included the following activities: (1) direct laser machining; (2) rotary ultrasonic machining; and (3) diamond abrasive grinding, including both resinoid and vitreous-bonded grinding wheels. Both friable and non-friable diamond types were included within the abrasive grinding study. The task also conducted a comprehensive survey of European experience in use of ceramic materials, principally aluminum oxide. Originally, the effort of this task was to extend through a prototype manufacturing demonstration of selected engine components. During the execution of this program, however changes were made to the scope of the project, altering the goals. The Program goal became only the development of assessment of their impacts on product strength and surface condition.

  7. Enabling Technologies for Ceramic Hot Section Components

    SciTech Connect

    Venkat Vedula; Tania Bhatia

    2009-04-30

    Silicon-based ceramics are attractive materials for use in gas turbine engine hot sections due to their high temperature mechanical and physical properties as well as lower density than metals. The advantages of utilizing ceramic hot section components include weight reduction, and improved efficiency as well as enhanced power output and lower emissions as a result of reducing or eliminating cooling. Potential gas turbine ceramic components for industrial, commercial and/or military high temperature turbine applications include combustor liners, vanes, rotors, and shrouds. These components require materials that can withstand high temperatures and pressures for long duration under steam-rich environments. For Navy applications, ceramic hot section components have the potential to increase the operation range. The amount of weight reduced by utilizing a lighter gas turbine can be used to increase fuel storage capacity while a more efficient gas turbine consumes less fuel. Both improvements enable a longer operation range for Navy ships and aircraft. Ceramic hot section components will also be beneficial to the Navy's Growth Joint Strike Fighter (JSF) and VAATE (Versatile Affordable Advanced Turbine Engines) initiatives in terms of reduced weight, cooling air savings, and capability/cost index (CCI). For DOE applications, ceramic hot section components provide an avenue to achieve low emissions while improving efficiency. Combustors made of ceramic material can withstand higher wall temperatures and require less cooling air. Ability of the ceramics to withstand high temperatures enables novel combustor designs that have reduced NO{sub x}, smoke and CO levels. In the turbine section, ceramic vanes and blades do not require sophisticated cooling schemes currently used for metal components. The saved cooling air could be used to further improve efficiency and power output. The objectives of this contract were to develop technologies critical for ceramic hot section

  8. Ceramic technology for advanced heat engines

    SciTech Connect

    Johnson, D.R.; Schulz, R.B.

    1994-10-01

    The Ceramic Technology Project was initiated in 1983 for the purpose of developing highly reliable structural ceramics for applications in advanced heat engines, such as automotive gas turbines and advanced heavy duty diesel engines. The reliability problem was determined to be a result of uncontrolled populations of processing flaws in the brittle, flaw-sensitive materials, along with microstructural features, such as grain boundary phases, that contribute to time dependent strength reduction in service at high temperatures. The approaches taken to develop high reliability ceramics included the development of tougher materials with greater tolerance to microstructural flaws, the development of advanced processing technology to minimize the size and number of flaws, and the development of mechanical testing methodology and the characterization of time dependent mechanical behavior, leading to a life prediction methodology for structural ceramics. The reliability goals of the program were largely met by 1993, but commercial implementation of ceramic engine components has been delayed by the high cost of the components. A new effort in Cost Effective Ceramics for Heat Engines was initiated in 1993 and is expected to develop the manufacturing technology leading to an order of magnitude cost reduction. The program has been planned for a five year period.

  9. Process for producing advanced ceramics

    DOEpatents

    Kwong, Kyei-Sing

    1996-01-01

    A process for the synthesis of homogeneous advanced ceramics such as SiC+AlN, SiAlON, SiC+Al.sub.2 O.sub.3, and Si.sub.3 N.sub.4 +AlN from natural clays such as kaolin, halloysite and montmorillonite by an intercalation and heat treatment method. Included are the steps of refining clays, intercalating organic compounds into the layered structure of clays, drying the intercalated mixture, firing the treated atmospheres and grinding the loosely agglomerated structure. Advanced ceramics produced by this procedure have the advantages of homogeneity, cost effectiveness, simplicity of manufacture, ease of grind and a short process time. Advanced ceramics produced by this process can be used for refractory, wear part and structure ceramics.

  10. FOREWORD: Focus on Advanced Ceramics Focus on Advanced Ceramics

    NASA Astrophysics Data System (ADS)

    Ohashi, Naoki

    2011-06-01

    Much research has been devoted recently to developing technologies for renewable energy and improving the efficiency of the processes and devices used in industry and everyday life. Efficient solutions have been found using novel materials such as platinum and palladium-based catalysts for car exhaust systems, samarium-cobalt and neodymium-iron-boron permanent magnets for electrical motors, and so on. However, their realization has resulted in an increasing demand for rare elements and in their deficit, the development of new materials based on more abundant elements and new functionalities of traditional materials. Moreover, increasing environmental and health concerns demand substitution of toxic or hazardous substances with nature-friendly alternatives. In this context, this focus issue on advanced ceramics aims to review current trends in ceramics science and technology. It is related to the International Conference on Science and Technology of Advanced Ceramics (STAC) held annually to discuss the emerging issues in the field of ceramics. An important direction of ceramic science is the collaboration between experimental and theoretical sciences. Recent developments in density functional theory and computer technology have enabled the prediction of physical and chemical properties of ceramics, thereby assisting the design of new materials. Therefore, this focus issue includes articles devoted to theory and advanced characterization techniques. As mentioned above, the potential shortage of rare elements is becoming critical to the industry and has resulted in a Japanese government initiative called the 'Ubiquitous Element Strategy'. This focus issue also includes articles related to this strategy and to the associated topics of energy conversion, such as phosphors for high-efficiency lighting and photocatalysts for solar-energy harvesting. We hope that this focus issue will provide a timely overview of current trends and problems in ceramics science and

  11. Advanced Power Electronics Components

    NASA Technical Reports Server (NTRS)

    Schwarze, Gene E.

    2004-01-01

    This paper will give a description and status of the Advanced Power Electronics Materials and Components Technology program being conducted by the NASA Glenn Research Center for future aerospace power applications. The focus of this research program is on the following: 1) New and/or significantly improved dielectric materials for the development of power capacitors with increased volumetric efficiency, energy density, and operating temperature. Materials being investigated include nanocrystalline and composite ceramic dielectrics and diamond-like carbon films; 2) New and/or significantly improved high frequency, high temperature, low loss soft magnetic materials for the development of transformers/inductors with increased power/energy density, electrical efficiency, and operating temperature. Materials being investigated include nanocrystalline and nanocomposite soft magnetic materials; 3) Packaged high temperature, high power density, high voltage, and low loss SiC diodes and switches. Development of high quality 4H- and 6H- SiC atomically smooth substrates to significantly improve device performance is a major emphasis of the SiC materials program; 4) Demonstration of high temperature (> 200 C) circuits using the components developed above.

  12. FILTER COMPONENT ASSESSMENT--CERAMIC CANDLES--

    SciTech Connect

    M.A. Alvin

    2004-04-23

    Efforts at Siemens Westinghouse Power Corporation (SWPC) have been focused on development of hot gas filter systems as an enabling technology for advanced coal and biomass-based gas turbine power generation applications. SWPC has been actively involved in the development of advanced filter materials and component configuration, has participated in numerous surveillance programs characterizing the material properties and microstructure of field tested filter elements, and has undertaken extended, accelerated filter life testing programs. This report summarizes the results of SWPC's filter component assessment efforts, identifying the performance and stability of porous monolithic, fiber reinforced, and filament wound ceramic hot gas candle filters, potentially for {ge}3 years of viable pressurized fluidized-bed combustion (PFBC) service operating life.

  13. Development in laser peening of advanced ceramics

    NASA Astrophysics Data System (ADS)

    Shukla, Pratik; Smith, Graham C.; Waugh, David G.; Lawrence, Jonathan

    2015-07-01

    Laser peening is a well-known process applicable to surface treat metals and alloys in various industrial sectors. Research in the area of laser peening of ceramics is still scarce and a complete laser-ceramic interaction is still unreported. This paper focuses on laser peening of SiC ceramics employed for cutting tools, armor plating, dental and biomedical implants, with a view to elucidate the unreported work. A detailed investigation was conducted with 1064nm Nd:YAG ns pulse laser to first understand the surface effects, namely: the topography, hardness, KIc and the microstructure of SiC advanced ceramics. The results showed changes in surface roughness and microstructural modification after laser peening. An increase in surface hardness was found by almost 2 folds, as the diamond footprints and its flaws sizes were considerably reduced, thus, enhancing the resistance of SiC to better withstand mechanical impact. This inherently led to an enhancement in the KIc by about 42%. This is attributed to an induction of compressive residual stress and phase transformation. This work is a first-step towards the development of a 3-dimensional laser peening technique to surface treat many advanced ceramic components. This work has shown that upon tailoring the laser peening parameters may directly control ceramic topography, microstructure, hardness and the KIc. This is useful for increasing the performance of ceramics used for demanding applications particularly where it matters such as in military. Upon successful peening of bullet proof vests could result to higher ballistic strength and resistance against higher sonic velocity, which would not only prevent serious injuries, but could also help to save lives of soldiers on the battle fields.

  14. Baseline Industry Analysis, Advance Ceramics Industry

    DTIC Science & Technology

    1993-04-01

    Commerce , Department of Defense, and the National Critical Technologies Panel. Advanced Ceramics, which include ceramic matrix composites, are found in...ceramics and materials industry being identified as a National Critical Technology, Commerce Emerging Technology, and Defense Critical Technology.’ There is...total procurement cost in advanced systems, and as much as ten percent of the electronics portion of those weapons. Ceramic capacitors are almost as

  15. Interdisciplinary research and development on the effects of the nature and properties of ceramic materials in the design of advanced structural components

    NASA Technical Reports Server (NTRS)

    1978-01-01

    An educational development and supportive research program on ceramic materials established to advance design methodology, improve materials, and develop engineers knowledgable in design with and use of high performance ceramic materials is described. Emphasis is on the structures and related materials problems in a ceramic turbine engine, but applications in coal gasification, solar conversion, and magnetohydrodynamic technologies are considered. Progress of various research projects in the areas of new materials, processing, characterization, and nondestructive testing is reported. Fracture toughness determination, extended X-ray absorption fine structure measurements, and grain boundary effects in beta-alumina are among the topics covered.

  16. Sensors for ceramic components in advanced propulsion systems: Summary of literature survey and concept analysis, task 3 report

    NASA Technical Reports Server (NTRS)

    Bennethum, W. H.; Sherwood, L. T.

    1988-01-01

    The results of a literature survey and concept analysis related to sensing techniques for measuring of surface temperature, strain, and heat flux for (non-specific) ceramic materials exposed to elevated temperatures (to 2200 K) are summarized. Concepts capable of functioning in a gas turbine hot section environment are favored but others are reviewed also. Recommendation are made for sensor development in each of the three areas.

  17. Investigation of properties and performance of ceramic composite components

    SciTech Connect

    Stinchcomb, W.W.; Reifsnider, K.L.; Dunyak, T.J.

    1992-06-15

    The objective of the work reported herein is to develop an understanding of the mechanical behavior of advanced ceramic composites subjected to elevated temperature and dynamic (cyclic) loading, to develop a test system and test methods to obtain the properties and performance information required to design engineering components made from ceramic composite materials, and to provide critical and comprehensive evaluations of such materials to material synthesizers and developers to support and enhance progress in ceramic composite material development. The accomplishments of the investigation include the design, development, and demonstration of a high temperature, biaxial mechanical test facility for ceramic composite tubes and the development and validation of a performance simulation model (MRLife) for ceramic composites.

  18. Nonintrusive temperature measurements on advanced turbomachinery components

    SciTech Connect

    Noel, B.W.; Turley, W.D.; Lewis, W.

    1992-12-31

    A nonintrusive, noncontacting method we developed for temperature measurements in hostile environments is well-suited for measurements on advanced turbine components. The method is not only superior to thermocouples in sufficiently difficult environments, but also is the only known method for making measurements in situations where no form of pyrometry works. We demonstrated the method, which uses laser-induced fluorescence of thermographic phosphors bonded to the component surfaces, on turbine blades and vanes in developmental turbine engines. The method is extendable to the much-higher temperatures expected inside advanced turbomachinery. Of particular note is the adaptability of the method to surface-temperature measurements on ceramics operating at high temperatures. In this temperature range, the ceramics become translucent, and surface emissivity becomes meaningless. We shall discuss the method, its advantages and limitations, recent test results on operating turbine engines, and the extension to ceramic components.

  19. Ceramic Composite Development for Gas Turbine Engine Hot Section Components

    NASA Technical Reports Server (NTRS)

    DiCarlo, James A.; VANrOODE, mARK

    2006-01-01

    The development of ceramic materials for incorporation into the hot section of gas turbine engines has been ongoing for about fifty years. Researchers have designed, developed, and tested ceramic gas turbine components in rigs and engines for automotive, aero-propulsion, industrial, and utility power applications. Today, primarily because of materials limitations and/or economic factors, major challenges still remain for the implementation of ceramic components in gas turbines. For example, because of low fracture toughness, monolithic ceramics continue to suffer from the risk of failure due to unknown extrinsic damage events during engine service. On the other hand, ceramic matrix composites (CMC) with their ability to display much higher damage tolerance appear to be the materials of choice for current and future engine components. The objective of this paper is to briefly review the design and property status of CMC materials for implementation within the combustor and turbine sections for gas turbine engine applications. It is shown that although CMC systems have advanced significantly in thermo-structural performance within recent years, certain challenges still exist in terms of producibility, design, and affordability for commercial CMC turbine components. Nevertheless, there exist some recent successful efforts for prototype CMC components within different engine types.

  20. Advanced Materials Development Program: Ceramic Technology for Advanced Heat Engines program plan, 1983--1993

    SciTech Connect

    Not Available

    1990-07-01

    The purpose of the Ceramic Technology for Advanced Heat Engines (CTAHE) Project is the development of an industrial technology base capable of providing reliable and cost-effective high temperature ceramic components for application in advanced heat engines. There is a deliberate emphasis on industrial'' in the purpose statement. The project is intended to support the US ceramic and engine industries by providing the needed ceramic materials technology. The heat engine programs have goals of component development and proof-of-concept. The CTAHE Project is aimed at developing generic basic ceramic technology and does not involve specific engine designs and components. The materials research and development efforts in the CTAHE Project are focused on the needs and general requirements of the advanced gas turbine and low heat rejection diesel engines. The CTAHE Project supports the DOE Office of Transportation Systems' heat engine programs, Advanced Turbine Technology Applications (ATTAP) and Heavy Duty Transport (HDT) by providing the basic technology required for development of reliable and cost-effective ceramic components. The heat engine programs provide the iterative component design, fabrication, and test development logic. 103 refs., 18 figs., 11 tabs.

  1. Advanced Ceramic Materials for Future Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Misra, Ajay

    2015-01-01

    With growing trend toward higher temperature capabilities, lightweight, and multifunctionality, significant advances in ceramic matrix composites (CMCs) will be required for future aerospace applications. The presentation will provide an overview of material requirements for future aerospace missions, and the role of ceramics and CMCs in meeting those requirements. Aerospace applications will include gas turbine engines, aircraft structure, hypersonic and access to space vehicles, space power and propulsion, and space communication.

  2. Precision grinding of advanced ceramics using superabrasives with glass bond

    SciTech Connect

    Ramanath, S.; Picone, J.

    1995-08-01

    Due to their superior properties such as high wear, heat resistance, low density, and high strength, advanced ceramic materials are being utilized in increasing number of applications and replacing metals and polymers. Wheels containing superabrasives (diamond or cubic boron nitride) are used to precision grind these materials to finished components in about 70% of the applications. The typical grinding wheel bonded by a thermosetting resin does not provide acceptable wheel life and material removal rates to make these ceramic materials commercially viable. Glass bonded superabrasive wheels developed recently and tailored for grinding of ceramics, have shown significant productivity through higher cut rates, longer wheel life values, and better form holding capabilities. Good strength of the ground ceramic work pieces indicates that the damage is maintained at low levels after grinding. Through case studies, this paper discusses the benefits of these new glass bonded wheel specifications, together with some of their limitations.

  3. Clay minerals for advanced ceramics

    SciTech Connect

    Murray, H.H. )

    1989-11-01

    The author describes new and improved beneficiation techniques available to allow the production of clay minerals of exceptionally high purity. This is particularly true for kaolins and smectites. Wet processing techniques include particle size separation, high intensity magnetic separation, chemical leaching, flotation, and selective flocculation. The blending of clay minerals with other minerals provides opportunities to make special ceramic materials such as cordierite and other minerals that have very special ceramic properties including low heat expansion, high fired strength, low absorption, and other desired qualities.

  4. ADVANCED SECOND GENERATION CERAMIC CANDLE FILTERS

    SciTech Connect

    M.A. Alvin

    2002-01-31

    system at the Foster Wheeler pressurized circulating fluidized-bed combustion (PCFBC), pilot-scale, test facility in Karhula, Finland. This report presents a summary of these efforts, defining the stability of the various porous ceramic filter materials, as well as component performance and extended life for use in advanced coal-based power systems.

  5. Advanced ceramic matrix composites for TPS

    NASA Technical Reports Server (NTRS)

    Rasky, Daniel J.

    1992-01-01

    Recent advances in ceramic matrix composite (CMC) technology provide considerable opportunity for application to future aircraft thermal protection system (TPS), providing materials with higher temperature capability, lower weight, and higher strength and stiffness than traditional materials. The Thermal Protection Material Branch at NASA Ames Research Center has been making significant progress in the development, characterization, and entry simulation (arc-jet) testing of new CMC's. This protection gives a general overview of the Ames Thermal Protection Materials Branch research activities, followed by more detailed descriptions of recent advances in very-high temperature Zr and Hf based ceramics, high temperature, high strength SiC matrix composites, and some activities in polymer precursors and ceramic coating processing. The presentation closes with a brief comparison of maximum heat flux capabilities of advanced TPS materials.

  6. Advanced Ceramics Property and Performance Measurements

    NASA Technical Reports Server (NTRS)

    Jenkins, Michael; Salem, Jonathan; Helfinstine, John; Quinn, George; Gonczy, Stephen

    2015-01-01

    Mechanical and physical properties of ceramic bodies can be difficult to measure correctly unless the proper techniques are used. The Advanced Ceramics Committee of ASTM, C-28, has developed dozens of consensus test standards and practices to measure various properties of a ceramic monolith, composite, or coating. The standards give the what, how, how not, and why for measurement of many mechanical, physical, thermal, and performance properties. Using these standards will provide accurate, reliable, and complete data for rigorous comparisons with other test results from your test lab, or another. The C-28 Committee has involved academics, producers, and users of ceramics to write and continually update more than 45 standards since the committees inception in 1986. Included in this poster is a pictogram of the C-28 standards and information on how to obtain individual copies with full details or the complete collection of all of the standards in one volume.

  7. Comparative study for the nondestructive testing of advanced ceramic materials by infrared thermography and holographic interferometry

    NASA Astrophysics Data System (ADS)

    Sfarra, S.; Ibarra-Castanedo, C.; Bendada, A.; Maldague, X.; Ambrosini, D.; Paoletti, D.

    2010-05-01

    Advanced ceramic materials are increasingly employed in varied and new applications where improved electrical, mechanical and/or thermal properties are sought. For instance, in a manner similar to carbon or glass fiber reinforced plastics, ceramic matrix composites (CMCs) are designed to improve the naturally brittle characteristics of monolithic ceramics thanks to the inclusion of fibers. Among the main interests for advanced ceramics are the increase in the operation temperature of components, the elimination of the use of cooling fluids, and weight savings. In this paper, the capabilities of infrared thermography and holographic interferometry are investigated and compared for the nondestructive assessment of advanced ceramic materials using three experimental specimens: (1) a monolithic green ceramic tile with fabricated defects, (2) a CMC specimen (from production reject) with a porous alumina matrix reinforced with glass fibers, and (3) a sandwich structure consisting on a carbon fiber honeycomb core with a ceramic plate bonded in one side.

  8. Robust Joining and Integration of Advanced Ceramics and Composites: Challenges, Opportunities, and Realities

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay

    2006-01-01

    Advanced ceramics and fiber reinforced composites are under active consideration for use in a wide variety of high temperature applications within the aeronautics, space transportation, energy, and nuclear industries. The engineering designs of ceramic and composite components require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. In addition, these components have to be joined or assembled with metallic sub-components. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing of high temperature joints in advanced ceramics and ceramic matrix composites will be presented. Silicon carbide based advanced ceramics and fiber reinforced composites in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology. In addition, some examples of metal-ceramic brazing will also be presented. Microstructure and high temperature mechanical properties of joints in silicon carbide ceramics and composites will be reported. Various joint design philosophies and design issues in joining of ceramics and composites will be discussed.

  9. Ceramic technology for advanced heat engines project

    SciTech Connect

    Not Available

    1990-09-01

    The Ceramic Technology for Advanced Heat Engines Project was developed by the Department of Energy's Office of Transportation Systems in Conservation and Renewable Energy. This project was developed to meet the ceramic technology requirements of the OTT's automotive technology programs. This project is managed by ORNL and is closely coordinated with complementary ceramics tasks funded by other DOE offices, NASA, DoD, and industry. Research is discussed under the following topics; Turbomilling of SiC Whiskers; microwave sintering of silicon nitride; and milling characterization; processing of monolithics; silicon nitride matrix; oxide matrix; silicate matrix; thermal and wear coatings; joining; design; contact interfaces; time-dependent behavior; environmental effects; fracture mechanics; nondestructive evaluation; and technology transfer. References, figures, and tables are included with each topic.

  10. High temperature ceramics for automobile gas turbines. Part 2: Development of ceramic components

    NASA Technical Reports Server (NTRS)

    Walzer, P.; Koehler, M.; Rottenkolber, P.

    1978-01-01

    The development of ceramic components for automobile gas turbine engines is described with attention given to the steady and unsteady thermal conditions the ceramics will experience, and their anti-corrosion and strain-resistant properties. The ceramics considered for use in the automobile turbines include hot-pressed Si3N4, reaction-sintered, isostatically pressed Si3N4, hot-pressed SiC, reaction-bonded SiC, and glass ceramics. Attention is given to the stress analysis of ceramic structures and the state of the art of ceramic structural technology is reviewed, emphasizing the use of ceramics for combustion chambers and ceramic shrouded turbomachinery (a fully ceramic impeller).

  11. Advanced diesel engine component development program, tasks 4-14

    NASA Astrophysics Data System (ADS)

    Kaushal, Tony S.; Weber, Karen E.

    1994-11-01

    This report summarizes the Advanced Diesel Engine Component Development (ADECD) Program to develop and demonstrate critical technology needed to advance the heavy-duty low heat rejection engine concept. Major development activities reported are the design, analysis, and fabrication of monolithic ceramic components; vapor phase and solid film lubrication; electrohydraulic valve actuation; and high pressure common rail injection. An advanced single cylinder test bed was fabricated as a laboratory tool in studying these advanced technologies. This test bed simulates the reciprocator for a system having no cooling system, turbo compounding, Rankine bottoming cycle, common rail injection, and variable valve actuation to achieve fuel consumption of 160 g/kW-hr (.26 lb/hp-hr). The advanced concepts were successfully integrated into the test engine. All ceramic components met their functional and reliability requirements. The firedeck, cast-in-place ports, valves, valve guides, piston cap, and piston ring were made from silicon nitride. Breakthroughs required to implement a 'ceramic' engine included the fabrication of air-gap cylinder heads, elimination of compression gaskets, machining of ceramic valve seats within the ceramic firedeck, fabrication of cast-in-place ceramic port liners, implementation of vapor phase lubrication, and elimination of the engine coolant system. Silicon nitride valves were successfully developed to meet several production abuse test requirements and incorporated into the test bed with a ceramic valve guide and solid film lubrication. The ADECD cylinder head features ceramic port shields to increase insulation and exhaust energy recovery. The combustion chamber includes a ceramic firedeck and piston cap. The tribological challenge posed by top ring reversal temperatures of 550 C was met through the development of vapor phase lubrication using tricresyl phosphate at the ring-liner interface. A solenoid-controlled, variable valve actuation system

  12. Advanced diesel engine component development program, tasks 4-14

    NASA Technical Reports Server (NTRS)

    Kaushal, Tony S.; Weber, Karen E.

    1994-01-01

    This report summarizes the Advanced Diesel Engine Component Development (ADECD) Program to develop and demonstrate critical technology needed to advance the heavy-duty low heat rejection engine concept. Major development activities reported are the design, analysis, and fabrication of monolithic ceramic components; vapor phase and solid film lubrication; electrohydraulic valve actuation; and high pressure common rail injection. An advanced single cylinder test bed was fabricated as a laboratory tool in studying these advanced technologies. This test bed simulates the reciprocator for a system having no cooling system, turbo compounding, Rankine bottoming cycle, common rail injection, and variable valve actuation to achieve fuel consumption of 160 g/kW-hr (.26 lb/hp-hr). The advanced concepts were successfully integrated into the test engine. All ceramic components met their functional and reliability requirements. The firedeck, cast-in-place ports, valves, valve guides, piston cap, and piston ring were made from silicon nitride. Breakthroughs required to implement a 'ceramic' engine included the fabrication of air-gap cylinder heads, elimination of compression gaskets, machining of ceramic valve seats within the ceramic firedeck, fabrication of cast-in-place ceramic port liners, implementation of vapor phase lubrication, and elimination of the engine coolant system. Silicon nitride valves were successfully developed to meet several production abuse test requirements and incorporated into the test bed with a ceramic valve guide and solid film lubrication. The ADECD cylinder head features ceramic port shields to increase insulation and exhaust energy recovery. The combustion chamber includes a ceramic firedeck and piston cap. The tribological challenge posed by top ring reversal temperatures of 550 C was met through the development of vapor phase lubrication using tricresyl phosphate at the ring-liner interface. A solenoid-controlled, variable valve actuation system

  13. Near net shape forming of advanced structural ceramic devices

    NASA Astrophysics Data System (ADS)

    Liu, Hao-Chih

    This research applied a combination of rapid prototyping techniques and ceramic gelcasting processes in the design and manufacturing of advanced structural ceramic components that cannot be fabricated by other shape-forming processes. An Assembly Mold SDM process, a derivative process of Shape Deposition Manufacturing, was adopted along with modified gelcasting with great success. The fabricated gas turbine rotors, inlet nozzles, and mesoscale burner arrays have demonstrated superior shape accuracy, mechanical strength, and surface smoothness with a feature size of 200 mum. The design concepts and functionalities of the ceramic devices were verified with performance tests. The shape complexity and surface quality of ceramic parts have been further improved by the use of a mold assembly made of a low melting temperature metal alloy. The introduction of metal alloy required modifications in the mold design, machining procedure, and ceramic processing. A complete shape forming process (from slurry to final parts) was developed for the low melting temperature metal alloy. In addition, the choice of ceramic material now includes SiC, which is critical to the development of micro heat exchangers. Forty-channel, high-aspect-ratio structured SiC heat exchangers were fabricated, and the thermal conductivity value of SiC was found to be comparable to that of steel. The catalyst deposition and ceramic precursor impregnation processes were proposed to enable use of the SiC heat exchangers as micro reactors. Micro-electro-mechanical-systems (MEMS)-related techniques such as SU-8 deep photolithography and polydimethylsiloxane (PDMS) soft lithography were combined with gelcasting to make micro patterns on structural ceramics. A feature size of 125 mum and aspect ratio of 8 have been achieved in the preliminary experiments. Based on the fabricated ceramic devices, a graphical method to characterize the shape attributes of complex-shaped components was proposed and used to compare

  14. Update on the prospects for ceramic engine components

    SciTech Connect

    Larsen, R.P.; Vyas, A.D.

    1991-01-01

    Ceramic components have the potential to improve the performance of automative heat engines. Earlier work by the authors involved predicting the timing and size of the ceramic engine component market using a worldwide Delphi survey. Relevant information from that earlier work is presented, and developments since then are summarized. 6 refs., 1 tab.

  15. Advanced lightweight ceramic candle filter module

    SciTech Connect

    Zievers, J.F.; Eggerstedt, P.

    1992-11-01

    To determine the economic effect of light weight ceramics, several sizes of filters were cost estimated for operation at 217.5 psi (15 bar) based on the use of all light weight ceramics (Fibro/Fibro) vs. the use of cooled alloy (RA300) tubesheets and silicon carbide candles (Alloy/SiC). A jet pulse delivery system was included in both estimates. The Fibro/Fibro system was estimated with the plenum design while the Alloy/SiC system was based on header/nozzle design. Battery limits were the filters and jet pulse delivery systems, Ex-works, with no main valves or dust removal systems. It was found that the cost of Fibro/Fibro components were consistently lower than the cost of the Alloy/SiC components; this comparison is illustrated in Figure 8.

  16. Advanced lightweight ceramic candle filter module

    SciTech Connect

    Zievers, J.F.; Eggerstedt, P.

    1992-01-01

    To determine the economic effect of light weight ceramics, several sizes of filters were cost estimated for operation at 217.5 psi (15 bar) based on the use of all light weight ceramics (Fibro/Fibro) vs. the use of cooled alloy (RA300) tubesheets and silicon carbide candles (Alloy/SiC). A jet pulse delivery system was included in both estimates. The Fibro/Fibro system was estimated with the plenum design while the Alloy/SiC system was based on header/nozzle design. Battery limits were the filters and jet pulse delivery systems, Ex-works, with no main valves or dust removal systems. It was found that the cost of Fibro/Fibro components were consistently lower than the cost of the Alloy/SiC components; this comparison is illustrated in Figure 8.

  17. Ceramic components manufacturing by selective laser sintering

    NASA Astrophysics Data System (ADS)

    Bertrand, Ph.; Bayle, F.; Combe, C.; Goeuriot, P.; Smurov, I.

    2007-12-01

    In the present paper, technology of selective laser sintering/melting is applied to manufacture net shaped objects from pure yttria-zirconia powders. Experiments are carried out on Phenix Systems PM100 machine with 50 W fibre laser. Powder is spread by a roller over the surface of 100 mm diameter alumina cylinder. Design of experiments is applied to identify influent process parameters (powder characteristics, powder layering and laser manufacturing strategy) to obtain high-quality ceramic components (density and micro-structure). The influence of the yttria-zirconia particle size and morphology onto powder layering process is analysed. The influence of the powder layer thickness on laser sintering/melting is studied for different laser beam velocity V ( V = 1250-2000 mm/s), defocalisation (-6 to 12 mm), distance between two neighbour melted lines (so-called "vectors") (20-40 μm), vector length and temperature in the furnace. The powder bed density before laser sintering/melting also has significant influence on the manufactured samples density. Different manufacturing strategies are applied and compared: (a) different laser beam scanning paths to fill the sliced surfaces of the manufactured object, (b) variation of vector length (c) different strategies of powder layering, (d) temperature in the furnace and (e) post heat treatment in conventional furnace. Performance and limitations of different strategies are analysed applying the following criteria: geometrical accuracy of the manufactured samples, porosity. The process stability is proved by fabrication of 1 cm 3 volume cube.

  18. Integrated Design Software Predicts the Creep Life of Monolithic Ceramic Components

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Significant improvements in propulsion and power generation for the next century will require revolutionary advances in high-temperature materials and structural design. Advanced ceramics are candidate materials for these elevated-temperature applications. As design protocols emerge for these material systems, designers must be aware of several innate features, including the degrading ability of ceramics to carry sustained load. Usually, time-dependent failure in ceramics occurs because of two different, delayedfailure mechanisms: slow crack growth and creep rupture. Slow crack growth initiates at a preexisting flaw and continues until a critical crack length is reached, causing catastrophic failure. Creep rupture, on the other hand, occurs because of bulk damage in the material: void nucleation and coalescence that eventually leads to macrocracks which then propagate to failure. Successful application of advanced ceramics depends on proper characterization of material behavior and the use of an appropriate design methodology. The life of a ceramic component can be predicted with the NASA Lewis Research Center's Ceramics Analysis and Reliability Evaluation of Structures (CARES) integrated design programs. CARES/CREEP determines the expected life of a component under creep conditions, and CARES/LIFE predicts the component life due to fast fracture and subcritical crack growth. The previously developed CARES/LIFE program has been used in numerous industrial and Government applications.

  19. Joining and Assembly of Silicon Carbide-based Advanced Ceramics and Composites for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Singh, M.

    2004-01-01

    Silicon carbide based advanced ceramics and fiber reinforced composites are under active consideration for use in wide variety of high temperature applications within the aeronautics, space transportation, energy, and nuclear industries. The engineering designs of ceramic and composite component require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. In addition these components have to be joined or assembled with metallic sub-components. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing o high temperature joints in ceramic matrix composites will be presented. Silicon carbide based advanced ceramics (CVD and hot pressed), and C/SiC and SiC/SiC composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and high temperature mechanical properties of joints in silicon carbide ceramics and CVI and melt infiltrated SiC matrix composites will,be reported. Various joint design philosophies and design issues in joining of ceramics and composites well be discussed.

  20. Recent Advances on Carbon Nanotubes and Graphene Reinforced Ceramics Nanocomposites

    PubMed Central

    Ahmad, Iftikhar; Yazdani, Bahareh; Zhu, Yanqiu

    2015-01-01

    Ceramics suffer the curse of extreme brittleness and demand new design philosophies and novel concepts of manufacturing to overcome such intrinsic drawbacks, in order to take advantage of most of their excellent properties. This has been one of the foremost challenges for ceramic material experts. Tailoring the ceramics structures at nanometre level has been a leading research frontier; whilst upgrading via reinforcing ceramic matrices with nanomaterials including the latest carbon nanotubes (CNTs) and graphene has now become an eminent practice for advanced applications. Most recently, several new strategies have indeed improved the properties of the ceramics/CNT nanocomposites, such as by tuning with dopants, new dispersions routes and modified sintering methods. The utilisation of graphene in ceramic nanocomposites, either as a solo reinforcement or as a hybrid with CNTs, is the newest development. This article will summarise the recent advances, key difficulties and potential applications of the ceramics nanocomposites reinforced with CNTs and graphene. PMID:28347001

  1. Advanced Environmental Barrier Coatings Development for Si-Based Ceramics

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Choi, R. Sung; Robinson, Raymond C.; Lee, Kang N.; Bhatt, Ramakrishna T.; Miller, Robert A.

    2005-01-01

    Advanced environmental barrier coating concepts based on multi-component HfO2 (ZrO2) and modified mullite systems are developed for monolithic Si3N4 and SiC/SiC ceramic matrix composite (CMC) applications. Comprehensive testing approaches were established using the water vapor cyclic furnace, high pressure burner rig and laser heat flux steam rig to evaluate the coating water vapor stability, cyclic durability, radiation and erosion resistance under simulated engine environments. Test results demonstrated the feasibility and durability of the environmental barrier coating systems for 2700 to 3000 F monolithic Si3N4 and SiC/SiC CMC component applications. The high-temperature-capable environmental barrier coating systems are being further developed and optimized in collaboration with engine companies for advanced turbine engine applications.

  2. Ceramic applications in the advanced Stirling automotive engine

    NASA Technical Reports Server (NTRS)

    Tomazic, W. A.; Cairelli, J. E.

    1977-01-01

    The ideal cycle, its application to a practical machine, and the specific advantages of high efficiency, low emissions, multi-fuel capability, and low noise of the stirling engine are discussed. Certain portions of the Stirling engine must operate continuously at high temperature. Ceramics offer the potential of cost reduction and efficiency improvement for advanced engine applications. Potential applications for ceramics in Stirling engines, and some of the special problems pertinent to using ceramics in the Stirling engine are described. The research and technology program in ceramics which is planned to support the development of advanced Stirling engines is outlined.

  3. Ceramic component manufacturing process development. Final report

    SciTech Connect

    Robinson, S.

    1996-09-30

    Ceramic materials are well suited for applications where temperature, wear, and corrosion resistance are necessary. The toughness and wear resistance properties that make ceramics desirable, also make fabrication of parts difficult. The objective of this CRADA was to increase the grinding efficiency on Ceradyne Incorporated silicon nitride. This was to be accomplished through optimization of grinding wheel life and increasing silicon nitride material removal rates. Experiments were conducted to determine the relationship between grinding parameters, wheel wear, and material removal rates. Due to excessive, unexplained variation in the experimental results, a consistent relationship between the selected grinding parameters and wheel wear could not be established. Maximum material removal rates were limited by spindle and table drive power. Additional experiments were conducted to evaluate high speed grinding. When compared to conventional grinding speeds, the material removal rates using high speed grinding (13,000 SFM) increased by a factor of five to ten with no degradation of fracture strength.

  4. Fabrication and Testing of Ceramic Matrix Composite Rocket Propulsion Components

    NASA Technical Reports Server (NTRS)

    Effinger, Michael; Clinton, R. G., Jr.; Dennis, Jay; Elam, Sandy; Genge, Gary; Eckel, Andy; Jaskowiak, Matha; Kiser, J. Doug; Lang, Jerry

    1999-01-01

    The National Aeronautics and Space Administration (NASA) is pursuing using ceramic matrix composites (CMC) as primary structural components for advanced rocket engines. This endeavor is due to the requirement of increasing safety by two orders of magnitude and reducing costs from $10,000/lb to $1,000/lb both within ten years. Out year goals are even more aggressive. Safety gains, through using CMCS, will be realized by increasing temperature margins, tolerance for extreme thermal transients, and damping capability of components and systems, by using components with lower weight and thermal conductivity, etc. Gains in cost reduction, through using CMCS, are anticipated by enabling higher performance systems, using lighter weight components and systems, enabling 100 mission reusability without system refurbishment, greatly reducing cooling requirements and erosion rates, selecting safe fabrication processes that are ideally cost competitive with metal processes at low volume production, etc. This philosophy contrasts the previous philosophy of rocket engine development focused largely on achieving the highest performance with metals and ablatives -- cost and safety were not the focal point of the initial design. Rocket engine components currently being pursued, largely C/SiC and SiC/SiC, include blisks or rotors, 10 foot by 8 foot nozzle ramps, gas generators, thrust chambers, and upperstage nozzles. The Simplex Turbopump CMC blisk effort has just successfully completed a 4.5 year development and test program. The other components mentioned are in the design or fabrication stage. Although the temperature limits of the CMC materials are not quantified in a realistic environment yet, CMC materials are projected to be the only way to achieve significant safety risks mitigation and cost reductions simultaneously. We, the end-users, material fabricators, technology facilitators, and government organizations are charged with developing and demonstrating a much safer and a

  5. Needs assessment for manufacturing ceramic gas turbine components

    SciTech Connect

    Johnson, D.R.; McSpadden, S.B.; Morris, T.O.; Pasto, A.E.

    1995-11-01

    An assessment of needs for the manufacturing of ceramic gas turbine components was undertaken to provide a technical basis for planning R&D activities to support DOE`s gas turbine programs. The manufacturing processes for ceramic turbine engine components were examined from design through final inspection and testing. The following technology needs were identified: Concurrent engineering early in the design phase to develop ceramic components that are more readily manufacturable. Additional effort in determining the boundaries of acceptable design dimensions and tolerances through experimental and/or analytical means. Provision, by the designer, of a CAD based model of the component early in the design cycle. Standardization in the way turbine components are dimensioned and toleranced, and in the way component datum features are defined. Rapid means of fabricating hard tooling, including intelligent systems for design of tooling and rapid prototyping of tooling. Determination of process capabilities by manufacturing significant numbers of parts. Development of more robust ceramic manufacturing processes which are tolerant of process variations. Development of intelligent processing as a means of controlling yield and quality of components. Development of computer models of key manufacturing steps, such as green forming to reduce the number of iterations required to manufacture intolerance components. Development of creep feed or other low-damage precision grinding for finish machining of components. Improved means of fixturing components for finish machining. Fewer and lower-cost final inspection requirements. Standard procedures, including consistent terminology and analytical software for dimensional inspection of components. Uniform data requirements from the US turbine engine companies. An agreed-upon system of naming ceramic materials and updating the name when changes have been made.

  6. Integration Science and Technology of Advanced Ceramics for Energy and Environmental Applications

    NASA Technical Reports Server (NTRS)

    Singh, M.

    2012-01-01

    The discovery of new and innovative materials has been known to culminate in major turning points in human history. The transformative impact and functional manifestation of new materials have been demonstrated in every historical era by their integration into new products, systems, assemblies, and devices. In modern times, the integration of new materials into usable products has a special relevance for the technological development and economic competitiveness of industrial societies. Advanced ceramic technologies dramatically impact the energy and environmental landscape due to potential wide scale applications in all aspects of energy production, storage, distribution, conservation, and efficiency. Examples include gas turbine propulsion systems, fuel cells, thermoelectrics, photovoltaics, distribution and transmission systems based on superconductors, nuclear power generation, and waste disposal. Robust ceramic integration technologies enable hierarchical design and manufacturing of intricate ceramic components starting with geometrically simpler units that are subsequently joined to themselves and/or to metals to create components with progressively higher levels of complexity and functionality. However, for the development of robust and reliable integrated systems with optimum performance under different operating conditions, the detailed understanding of various thermochemical and thermomechanical factors is critical. Different approaches are required for the integration of ceramic-metal and ceramic-ceramic systems across length scales (macro to nano). In this presentation, a few examples of integration of ceramic to metals and ceramic to ceramic systems will be presented. Various challenges and opportunities in design, fabrication, and testing of integrated similar (ceramic-ceramic) and dissimilar (ceramic-metal) material systems will be discussed. Potential opportunities and need for the development of innovative design philosophies, approaches, and

  7. Advanced Ceramic Matrix Composites (CMCs) for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Singh, M.

    2005-01-01

    Advanced ceramic matrix composites (CMCs) are enabling materials for a number of demanding applications in aerospace, energy, and nuclear industries. In the aerospace systems, these materials are being considered for applications in hot sections of jet engines such as the combustor liner, vanes, nozzle components, nose cones, leading edges of reentry vehicles, and space propulsion components. Applications in the energy and environmental industries include radiant heater tubes, heat exchangers, heat recuperators, gas and diesel particulate filters, and components for land based turbines for power generation. These materials are also being considered for use in the first wall and blanket components of fusion reactors. In the last few years, a number of CMC components have been developed and successfully tested for various aerospace and ground based applications. However, a number of challenges still remain slowing the wide scale implementation of these materials. They include robust fabrication and manufacturing, assembly and integration, coatings, property modeling and life prediction, design codes and databases, repair and refurbishment, and cost. Fabrication of net and complex shape components with high density and tailorable matrix properties is quite expensive, and even then various desirable properties are not achievable. In this presentation, a number of examples of successful CMC component development and testing will be provided. In addition, critical need for robust manufacturing, joining and assembly technologies in successful implementation of these systems will be discussed.

  8. Some design considerations for ceramic components in heat engine applications

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John P.

    1986-01-01

    The design methodology for brittle material structures which is being developed and used at the Lewis Research Center for sizing ceramic components in heat engine applications is reviewed. Theoretical aspects of designing with structural ceramics are discussed, and a general purpose reliability program for predicting fast fracture response due to volume distributed flaws is described. Statistical treatment of brittle behavior, based on the Weibull model, is reviewed and its advantages, as well as drawbacks, are listed. A mechanistic statistical fracture theory, proposed by Batdorf to overcome the Weibull model limitations and based on Griffith fracture mechanics, is summarized. Failure probability predictions are made for rotating annular Si3N4 disks using various fracture models, and the results are compared to actual failure data. The application of these design methods to Government funded ceramics engine demonstration programs is surveyed. The uncertainty in observed component performance emphasizes the need for proof testing and improved nondestructive evaluation to guarantee adequate structural integrity.

  9. Polymer, metal, and ceramic matrix composites for advanced aircraft engine applications

    SciTech Connect

    Mc Daniels, D.L.; Serafini, T.T.; Di Carlo, J.A.

    1986-06-01

    Advanced aircraft engine research within NASA Lewis focuses on propulsion systems for subsonic, supersonic, and hypersonic aircraft. Each of these flight regimes requires different types of engines, but all require advanced materials to meet their goals of performance, thrust-to-weight ratio, and fuel efficiency. The high strength/weight and stiffness/weight properties of resin, metal, and ceramic matrix composites will play an increasingly key role in meeting these performance requirements. At NASA Lewis, research is ongoing to apply graphite/polyimide composites to engine components and to develop polymer matrices with higher operating temperature capabilities. Metal matrix composites, using magnesium, aluminum, titanium, and superalloy matrices, are being developed for application to static and rotating engine components, as well as for space applications, over a broad temperature range. Ceramic matrix composites are also being examined to increase the toughness and reliability of ceramics for application to high-temperature engine structures and components.

  10. Advanced ceramic cladding for water reactor fuel

    SciTech Connect

    Feinroth, H.

    2000-07-01

    Under the US Department of Energy's Nuclear Energy Research Initiatives (NERI) program, continuous fiber ceramic composites (CFCCs) are being developed as cladding for water reactor fuel elements. The purpose is to substantially increase the passive safety of water reactors. A development effort was initiated in 1991 to fabricate CFCC-clad tubes using commercially available fibers and a sol-gel process developed by McDermott Technologies. Two small-diameter CFCC tubes were fabricated using pure alumina and alumina-zirconia fibers in an alumina matrix. Densities of {approximately}60% of theoretical were achieved. Higher densities are required to guarantee fission gas containment. This NERI work has just begun, and only preliminary results are presented herein. Should the work prove successful, further development is required to evaluate CFCC cladding and performance, including in-pile tests containing fuel and exploring a marriage of CFCC cladding materials with suitable advanced fuel and core designs. The possibility of much higher temperature core designs, possibly cooled with supercritical water, and achievement of plant efficiencies {ge}50% would be examined.

  11. Impact design methods for ceramic components in gas turbine engines

    NASA Technical Reports Server (NTRS)

    Song, J.; Cuccio, J.; Kington, H.

    1991-01-01

    Methods currently under development to design ceramic turbine components with improved impact resistance are presented. Two different modes of impact damage are identified and characterized, i.e., structural damage and local damage. The entire computation is incorporated into the EPIC computer code. Model capability is demonstrated by simulating instrumented plate impact and particle impact tests.

  12. Test model designs for advanced refractory ceramic materials

    NASA Technical Reports Server (NTRS)

    Tran, Huy Kim

    1993-01-01

    The next generation of space vehicles will be subjected to severe aerothermal loads and will require an improved thermal protection system (TPS) and other advanced vehicle components. In order to ensure the satisfactory performance system (TPS) and other advanced vehicle materials and components, testing is to be performed in environments similar to space flight. The design and fabrication of the test models should be fairly simple but still accomplish test objectives. In the Advanced Refractory Ceramic Materials test series, the models and model holders will need to withstand the required heat fluxes of 340 to 817 W/sq cm or surface temperatures in the range of 2700 K to 3000 K. The model holders should provide one dimensional (1-D) heat transfer to the samples and the appropriate flow field without compromising the primary test objectives. The optical properties such as the effective emissivity, catalytic efficiency coefficients, thermal properties, and mass loss measurements are also taken into consideration in the design process. Therefore, it is the intent of this paper to demonstrate the design schemes for different models and model holders that would accommodate these test requirements and ensure the safe operation in a typical arc jet facility.

  13. Advances in design and performance of SHE system components

    NASA Astrophysics Data System (ADS)

    McBride, J. R.; Novak, R. F.; Schmatz, D. J.; Copple, W. B.; Brockway, J. T.

    The sodium heat engine (SHE), a thermoelectric energy conversion device that operates with no moving parts at conversion efficiencies projected to reach 25-30 percent, is discussed. Recent progress in the design and performance of components used in the development of a 1000-W SHE is reported. Advances in long-life electrodes, high-temperature ceramic-to-metal seals, electromagnetic pumps, radiation shields, and current-gathering systems are discussed. Parasitic losses and modular designs are considered.

  14. Award-Winning CARES/Life Ceramics Durability Evaluation Software Is Making Advanced Technology Accessible

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Products made from advanced ceramics show great promise for revolutionizing aerospace and terrestrial propulsion and power generation. However, ceramic components are difficult to design because brittle materials in general have widely varying strength values. The CARES/Life software developed at the NASA Lewis Research Center eases this by providing a tool that uses probabilistic reliability analysis techniques to optimize the design and manufacture of brittle material components. CARES/Life is an integrated package that predicts the probability of a monolithic ceramic component's failure as a function of its time in service. It couples commercial finite element programs--which resolve a component's temperature and stress distribution - with reliability evaluation and fracture mechanics routines for modeling strength - limiting defects. These routines are based on calculations of the probabilistic nature of the brittle material's strength.

  15. Subcritical crack-growth behavior in advanced silicon nitride ceramics

    NASA Astrophysics Data System (ADS)

    Bhatnagar, Ajay

    Advanced silicon nitride ceramics (Sisb3Nsb4) are leading candidates for structural components in gas turbine and reciprocating engines. However, widespread use of these materials has been deterred due to their low fracture toughness under tensile loads. In the last decade, novel processing techniques have allowed extrinsic toughening of this material through grain bridging processes. The extrinsic toughening mechanisms, however, are prone to subcritical crack-growth processes through environmental, mechanical and high temperature degradation mechanisms. Understanding these failure mechanisms is critical for long term reliability and design. In the first part of this study, fracture and environmentally-assisted subcritical crack-growth processes were examined in bulk Y-Si-Al-O-N oxynitride glasses with compositions typical of the grain boundary phase of silicon nitride ceramics. Both long crack as well as short crack behavior were investigated to establish a reliable fracture toughness value and to elucidate the anomalous densification behavior of the oxynitride glass under indentation loads. Environmentally assisted subcritical crack-growth processes were studied in inert, moist and wet environments under both cyclic and static loading conditions and compared to commercial soda lime and borosilicate glasses. The second part of this study involved the effect of loading, microstructure and temperature on subcritical crack-growth behavior in silicon nitride ceramics. Crack-growth rates under an alternating applied stress intensity were compared to those under static loads. The effect of microstructure on fatigue crack-growth rates was determined in silicon nitrides sintered using different processing techniques and with different grain sizes. Unique experimental techniques were used to determine subcritical crack-growth behavior from room temperature to elevated temperatures of 1250sp°C. Frictional wear models were used to explain the trends in experimental data at

  16. Environment Conscious Ceramics (Ecoceramics): An Eco-Friendly Route to Advanced Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Singh, M.

    2001-01-01

    Environment conscious ceramics (Ecoceramics) are a new class of materials, which can be produced with renewable natural resources (wood) or wood wastes (wood sawdust). This technology provides an eco-friendly route to advanced ceramic materials. Ecoceramics have tailorable properties and behave like ceramic materials manufactured by conventional approaches. Silicon carbide-based ecoceramics have been fabricated by reactive infiltration of carbonaceous preforms by molten silicon or silicon-refractory metal alloys. The fabrication approach, microstructure, and mechanical properties of SiC-based ecoceramics are presented.

  17. Research on chemical vapor deposition processes for advanced ceramic coatings

    NASA Technical Reports Server (NTRS)

    Rosner, Daniel E.

    1993-01-01

    Our interdisciplinary background and fundamentally-oriented studies of the laws governing multi-component chemical vapor deposition (VD), particle deposition (PD), and their interactions, put the Yale University HTCRE Laboratory in a unique position to significantly advance the 'state-of-the-art' of chemical vapor deposition (CVD) R&D. With NASA-Lewis RC financial support, we initiated a program in March of 1988 that has led to the advances described in this report (Section 2) in predicting chemical vapor transport in high temperature systems relevant to the fabrication of refractory ceramic coatings for turbine engine components. This Final Report covers our principal results and activities for the total NASA grant of $190,000. over the 4.67 year period: 1 March 1988-1 November 1992. Since our methods and the technical details are contained in the publications listed (9 Abstracts are given as Appendices) our emphasis here is on broad conclusions/implications and administrative data, including personnel, talks, interactions with industry, and some known applications of our work.

  18. Progress in ceramic component fabrication technology

    NASA Technical Reports Server (NTRS)

    Storm, R. S.; Lashway, R. W.

    1982-01-01

    Net shape techniques have been used in the production of rotating and static vehicular engine high-temperature components composed of sintered Alpha-SiC (SASC). Injection-molded rotors have been cold spin tested, as well as a slip-cast combustor assembly hot rig. SASC pistons and cylinder liners have also been constructed for an opposed piston, two-cycle diesel test rig while test results are presented. An uncooled, minimum-friction internal combustion engine with multi-fuel capability due to its elevated combustion temperatures appears to be achievable in the near term by means of SASC techniques. The flexural strength of SASC at 1500 C is 446 MPa, identical to that at room temperature, and excellent strength retention has been demonstrated after 3500 hours of cyclic exposure.

  19. Durability evaluation of ceramic components using CARES/LIFE

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Powers, Lynn M.; Janosik, Lesley A.; Gyekenyesi, John P.

    1994-01-01

    The computer program CARES/LIFE calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. This program is an extension of the CARES (Ceramics Analysis and Reliability Evaluation of Structures) computer program. CARES/LIFE accounts for the phenomenon of subcritical crack growth (SCG) by utilizing the power law, Paris law, or Walker equation. The two-parameter Weibull cumulative distribution function is used to characterize the variation in component strength. The effects of multiaxial stresses are modeled using either the principle of independent action (PIA), the Weibull normal stress averaging method (NSA), or the Batdorf theory. Inert strength and fatigue parameters are estimated from rupture strength data of naturally flawed specimens loaded in static, dynamic, or cyclic fatigue. Application of this design methodology is demonstrated using experimental data from alumina bar and disk flexure specimens which exhibit SCG when exposed to water.

  20. Time-dependent reliability analysis of ceramic engine components

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.

    1993-01-01

    The computer program CARES/LIFE calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. This program is an extension of the CARES (Ceramics Analysis and Reliability Evaluation of Structures) computer program. CARES/LIFE accounts for the phenomenon of subcritical crack growth (SCG) by utilizing either the power or Paris law relations. The two-parameter Weibull cumulative distribution function is used to characterize the variation in component strength. The effects of multiaxial stresses are modeled using either the principle of independent action (PIA), the Weibull normal stress averaging method (NSA), or the Batdorf theory. Inert strength and fatigue parameters are estimated from rupture strength data of naturally flawed specimens loaded in static, dynamic, or cyclic fatigue. Two example problems demonstrating proof testing and fatigue parameter estimation are given.

  1. Test Standard Developed for Determining the Slow Crack Growth of Advanced Ceramics at Ambient Temperature

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Salem, Jonathan A.

    1998-01-01

    The service life of structural ceramic components is often limited by the process of slow crack growth. Therefore, it is important to develop an appropriate testing methodology for accurately determining the slow crack growth design parameters necessary for component life prediction. In addition, an appropriate test methodology can be used to determine the influences of component processing variables and composition on the slow crack growth and strength behavior of newly developed materials, thus allowing the component process to be tailored and optimized to specific needs. At the NASA Lewis Research Center, work to develop a standard test method to determine the slow crack growth parameters of advanced ceramics was initiated by the authors in early 1994 in the C 28 (Advanced Ceramics) committee of the American Society for Testing and Materials (ASTM). After about 2 years of required balloting, the draft written by the authors was approved and established as a new ASTM test standard: ASTM C 1368-97, Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress-Rate Flexural Testing at Ambient Temperature. Briefly, the test method uses constant stress-rate testing to determine strengths as a function of stress rate at ambient temperature. Strengths are measured in a routine manner at four or more stress rates by applying constant displacement or loading rates. The slow crack growth parameters required for design are then estimated from a relationship between strength and stress rate. This new standard will be published in the Annual Book of ASTM Standards, Vol. 15.01, in 1998. Currently, a companion draft ASTM standard for determination of the slow crack growth parameters of advanced ceramics at elevated temperatures is being prepared by the authors and will be presented to the committee by the middle of 1998. Consequently, Lewis will maintain an active leadership role in advanced ceramics standardization within ASTM

  2. Machining and inspection of structural ceramic components. CRADA final report for CRADA number Y-1292-0078

    SciTech Connect

    Counts, R.W.; Albright, S.; Ritland, M.

    1996-09-30

    This document is the final report of the Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Systems, Inc. (Energy Systems) and the Coors Ceramics Company (Coors). The purpose of this CRADA was to develop advanced technology and manufacturing practices for machining and inspecting ceramic components. Specific CRADA objectives were accomplished through the completion of six projects at four separate Coors facilities. The projects included the development of an analytical model to simulate the mechanics of a powder rolling process, development and testing of a microwave-based system for measuring the density of conveyed ceramic material, and the development and testing of four machine vision inspection systems. This CRADA benefited the U.S. Department of Energy (DOE) activities associated with advanced heat engines, enhanced critical manufacturing skills within the DOE complex for fabricating precision, high quality workpieces from difficult-to-machine materials, and enabled U.S. industry to maintain a position of leadership in the structural ceramics field.

  3. Plutonium immobilization ceramic feed batching component test report

    SciTech Connect

    Erickson, S.A.

    1999-10-04

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with high level waste glass for permanent storage. Ceramic feed batching (CFB) is one of the first process steps involved with first stage plutonium immobilization. The CFB step will blend plutonium oxide powder before it is combined with other materials to make pucks. This report discusses the Plutonium Immobilization CFB process preliminary concept (including a process block diagram), batch splitting component test results, CFB development areas, and FY 1999 and 2000 CFB program milestones.

  4. Development of advanced ceramic matrix composite insulators for electromagnetic railguns

    SciTech Connect

    Stevenson, R.D.; Rosenwasser, S.N.; Washburn, R.M. )

    1991-01-01

    Stiff, erosion resistant insulator materials are currently needed as bore insulators for electromagnetic railguns. In this paper a status review is given of an ongoing program to develop stiff erosion resistant ceramic composite materials capable of withstanding the severe mechanical, electrical and thermal environment that exists in the bore of such devices. Analytical predictions were made in order to establish property goals. A wide variety of advanced ceramic composite insulator panels have been fabricated and tested. A railgun was modified to serve as a test device for evaluating the new insulator materials. Work has been initiated to scale up the fabrication of selected advanced ceramic composite insulator parts to be tested in full-size railguns.

  5. Ceramic component development analysis -- Volume 1. Final report

    SciTech Connect

    Boss, D.E.

    1998-06-09

    The development of advanced filtration media for advanced fossil-fueled power generating systems is a critical step in meeting the performance and emissions requirements for these systems. While porous metal and ceramic candle-filters have been available for some time, the next generation of filters will include ceramic-matrix composites (CMCs) (Techniweave/Westinghouse, Babcock and Wilcox (B and W), DuPont Lanxide Composites), intermetallic alloys (Pall Corporation), and alternate filter geometries (CeraMem Separations). The goal of this effort was to perform a cursory review of the manufacturing processes used by 5 companies developing advanced filters from the perspective of process repeatability and the ability for their processes to be scale-up to produce volumes. Given the brief nature of the on-site reviews, only an overview of the processes and systems could be obtained. Each of the 5 companies had developed some level of manufacturing and quality assurance documentation, with most of the companies leveraging the procedures from other products they manufacture. It was found that all of the filter manufacturers had a solid understanding of the product development path. Given that these filters are largely developmental, significant additional work is necessary to understand the process-performance relationships and projecting manufacturing costs.

  6. Fabrication and Testing of Ceramic Matrix Composite Rocket Propulsion Components

    NASA Technical Reports Server (NTRS)

    Effinger, M. R.; Clinton, R. C., Jr.; Dennis, J.; Elam, S.; Genge, G.; Eckel, A.; Jaskowiak, M. H.; Kiser, J. D.; Lang, J.

    2001-01-01

    NASA has established goals for Second and Third Generation Reusable Launch Vehicles. Emphasis has been placed on significantly improving safety and decreasing the cost of transporting payloads to orbit. Ceramic matrix composites (CMC) components are being developed by NASA to enable significant increases in safety and engineer performance, while reducing costs. The development of the following CMC components are being pursued by NASA: (1) Simplex CMC Blisk; (2) Cooled CMC Nozzle Ramps; (3) Cooled CMC Thrust Chambers; and (4) CMC Gas Generator. These development efforts are application oriented, but have a strong underpinning of fundamental understanding of processing-microstructure-property relationships relative to structural analyses, nondestructive characterization, and material behavior analysis at the coupon and component and system operation levels. As each effort matures, emphasis will be placed on optimizing and demonstrating material/component durability, ideally using a combined Building Block Approach and Build and Bust Approach.

  7. Joining of ceramics for advanced heavy-duty diesels

    SciTech Connect

    Moorhead, A.J.; Keating, H.

    1986-03-01

    The wettability and adherence in vacuum of a series of metal alloys on several oxide ceramics were investigated with the goal of identifying those compositions suitable as filler metals for direct brazing of ceramics in uncooled diesel engine applications. Wetting behavior was determined by the sessile-drop technique. Adherence was measured by several tests including sessile-drop shear, flexure strength of ceramics brazed in a butt-joint configuration, fracture toughness using a composite double cantilever beam specimen, and, in the case of ceramic-metal brazements, by a bar/pad shear test. Compositions were identified in both the Cu-Ag-Ti and Cu-Au-Ti ternary systems that wet and strongly adhered to high-purity aluminas, partially stabilized zirconia ceramics, and alumina reinforced with SiC whiskers. Excellent flexural strengths, at temperatures up to 600/sup 0/C, of brazements containing these filler metals indicate that these materials are good candidates for use in advanced heavy-duty diesel engines. They have the advantage over competing systems of not requiring that the ceramic be metallized before brazing.

  8. Fracture Toughness of Advanced Structural Ceramics: Applying ASTM C1421

    DOE PAGES

    Swab, Jeffrey J.; Tice, Jason; Wereszczak, Andrew A.; ...

    2014-11-03

    The three methods of determining the quasi-static Mode I fracture toughness (KIc) (surface crack in flexure – SC, single-edge precracked beam – PB, and chevron notched beam – VB) found in ASTM C1421 were applied to a variety of advanced ceramic materials. All three methods produced valid and comparable KIc values for the Al2O3, SiC, Si3N4 and SiAlON ceramics examined. However, not all methods could successfully be applied to B4C, ZrO2 and WC ceramics due to a variety of material factors. The coarse-grained microstructure of one B4C hindered the ability to observe and measure the precracks generated in the SCmore » and PB methods while the transformation toughening in the ZrO2 prevented the formation of the SC and PB precracks and thus made it impossible to use either method on this ceramic. The high strength and elastic modulus of the WC made it impossible to achieve stable crack growth using the VB method because the specimen stored a tremendous amount of energy prior to fracture. Even though these methods have passed the rigors of the standardization process there are still some issues to be resolved when the methods are applied to certain classes of ceramics. We recommend that at least two of these methods be employed to determine the KIc, especially when a new or unfamiliar ceramic is being evaluated.« less

  9. Recent advances in ALON optical ceramic

    NASA Astrophysics Data System (ADS)

    Wahl, Joseph M.; Hartnett, Thomas M.; Goldman, Lee M.; Twedt, Richard; Warner, Charles

    2005-05-01

    Aluminum Oxynitride (ALONTM Optical Ceramic) is a transparent ceramic material which combines transparency from the UV to the MWIR with excellent mechanical properties. ALON"s optical and mechanical properties are isotropic by virtue of its cubic crystalline structure. Consequently, ALON is transparent in its polycrystalline form and can be made by conventional powder processing techniques. This combination of properties and manufacturability make ALON suitable for a range of applications from IR windows, domes and lenses to transparent armor. The technology for producing transparent ALON was developed at Raytheon and has been transferred to Surmet Corporation where it is currently in production. Surmet is currently selling ALON into a number of military (e.g., windows and domes) and commercial (e.g., supermarket scanner windows) applications. The capability to manufacture large ALON windows for both sensor window and armor applications is in place. ALON windows up to 20x30 inches have been fabricated. In addition, the capability to shape and polish these large and curved windows is being developed and demonstrated at Surmet. Complex shapes, both hyper-hemispherical and conformal, are also under development and will be described.

  10. Strength and flexibility properties of advanced ceramic fabrics

    NASA Technical Reports Server (NTRS)

    Sawko, P. M.; Tran, H. K.

    1985-01-01

    The mechanical properties of four advanced ceramic fabrics are measured at a temperature range of 23 C to 1200 C. The fabrics evaluated are silica, high-and low-boria content aluminoborosilicate, and silicon carbide. Properties studied include fabric break strengths from room temperature to 1200 C, and bending durability after temperature conditioning at 1200 C and 1400 C. The interaction of the fabric and ceramic insulation is also studied for shrinkage, appearance, bend resistance, and fabric-to-insulation bonding. Based on these tests, the low-boria content aluminoborosilicate fabric retains more strength and fabric durability than the other fabrics studied at high temperature.

  11. Strength and flexibility properties of advanced ceramic fabrics

    NASA Technical Reports Server (NTRS)

    Sawko, P. M.; Tran, H. K.

    1985-01-01

    The mechanical properties of four advanced ceramic fabrics were measured at a temperature range of 23C to 1200C. The fabrics evaluated were silica, high and low-boria content aluminoborosilicate, and silicon carbide. Properties studied included fabric break strengths from room temperature to 1200C, and bending durability after temperature conditioning at 1200C and 1400C. The interaction of the fabric and ceramic insulation was also studied for shrinkage, appearance, bend resistance, and fabric-to-insulation bonding. Based on these tests, the low-boria content aluminoborosilicate fabric retained more strength and fabric durability than the other fabrics studied at high temperature.

  12. Advanced ceramic coating development for industrial/utility gas turbines

    NASA Technical Reports Server (NTRS)

    Vogan, J. W.; Stetson, A. R.

    1982-01-01

    A program was conducted with the objective of developing advanced thermal barrier coating (TBC) systems. Coating application was by plasma spray. Duplex, triplex and graded coatings were tested. Coating systems incorporated both NiCrAly and CoCrAly bond coats. Four ceramic overlays were tested: ZrO2.82O3; CaO.TiO2; 2CaO.SiO2; and MgO.Al2O3. The best overall results were obtained with a CaO.TiO2 coating applied to a NiCrAly bond coat. This coating was less sensitive than the ZrO2.8Y2O3 coating to process variables and part geometry. Testing with fuels contaminated with compounds containing sulfur, phosphorus and alkali metals showed the zirconia coatings were destabilized. The calcium titanate coatings were not affected by these contaminants. However, when fuels were used containing 50 ppm of vanadium and 150 ppm of magnesium, heavy deposits were formed on the test specimens and combustor components that required frequent cleaning of the test rig. During the program Mars engine first-stage turbine blades were coated and installed for an engine cyclic endurance run with the zirconia, calcium titanate, and calcium silicate coatings. Heavy spalling developed with the calcium silicate system. The zirconia and calcium titanate systems survived the full test duration. It was concluded that these two TBC's showed potential for application in gas turbines.

  13. Advanced ceramic materials for next-generation nuclear applications

    NASA Astrophysics Data System (ADS)

    Marra, John

    2011-10-01

    The nuclear industry is at the eye of a 'perfect storm' with fuel oil and natural gas prices near record highs, worldwide energy demands increasing at an alarming rate, and increased concerns about greenhouse gas (GHG) emissions that have caused many to look negatively at long-term use of fossil fuels. This convergence of factors has led to a growing interest in revitalization of the nuclear power industry within the United States and across the globe. Many are surprised to learn that nuclear power provides approximately 20% of the electrical power in the US and approximately 16% of the world-wide electric power. With the above factors in mind, world-wide over 130 new reactor projects are being considered with approximately 25 new permit applications in the US. Materials have long played a very important role in the nuclear industry with applications throughout the entire fuel cycle; from fuel fabrication to waste stabilization. As the international community begins to look at advanced reactor systems and fuel cycles that minimize waste and increase proliferation resistance, materials will play an even larger role. Many of the advanced reactor concepts being evaluated operate at high-temperature requiring the use of durable, heat-resistant materials. Advanced metallic and ceramic fuels are being investigated for a variety of Generation IV reactor concepts. These include the traditional TRISO-coated particles, advanced alloy fuels for 'deep-burn' applications, as well as advanced inert-matrix fuels. In order to minimize wastes and legacy materials, a number of fuel reprocessing operations are being investigated. Advanced materials continue to provide a vital contribution in 'closing the fuel cycle' by stabilization of associated low-level and high-level wastes in highly durable cements, ceramics, and glasses. Beyond this fission energy application, fusion energy will demand advanced materials capable of withstanding the extreme environments of high

  14. Modeling injection molding of net-shape active ceramic components.

    SciTech Connect

    Baer, Tomas; Cote, Raymond O.; Grillet, Anne Mary; Yang, Pin; Hopkins, Matthew Morgan; Noble, David R.; Notz, Patrick K.; Rao, Rekha Ranjana; Halbleib, Laura L.; Castaneda, Jaime N.; Burns, George Robert; Mondy, Lisa Ann; Brooks, Carlton, F.

    2006-11-01

    To reduce costs and hazardous wastes associated with the production of lead-based active ceramic components, an injection molding process is being investigated to replace the current machining process. Here, lead zirconate titanate (PZT) ceramic particles are suspended in a thermoplastic resin and are injected into a mold and allowed to cool. The part is then bisque fired and sintered to complete the densification process. To help design this new process we use a finite element model to describe the injection molding of the ceramic paste. Flow solutions are obtained using a coupled, finite-element based, Newton-Raphson numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. Thermal, rheological, and wetting properties of the PZT paste are measured for use as input to the model. The viscosity of the PZT is highly dependent both on temperature and shear rate. One challenge in modeling the injection process is coming up with appropriate constitutive equations that capture relevant phenomenology without being too computationally complex. For this reason we model the material as a Carreau fluid and a WLF temperature dependence. Two-dimensional (2D) modeling is performed to explore the effects of the shear in isothermal conditions. Results indicate that very low viscosity regions exist near walls and that these results look similar in terms of meniscus shape and fill times to a simple Newtonian constitutive equation at the shear-thinned viscosity for the paste. These results allow us to pick a representative viscosity to use in fully three-dimensional (3D) simulation, which because of numerical complexities are restricted to using a Newtonian constitutive equation. Further 2D modeling at nonisothermal conditions shows that the choice of

  15. Dental ceramics: An update

    PubMed Central

    Shenoy, Arvind; Shenoy, Nina

    2010-01-01

    In the last few decades, there have been tremendous advances in the mechanical properties and methods of fabrication of ceramic materials. While porcelain-based materials are still a major component of the market, there have been moves to replace metal ceramics systems with all ceramic systems. Advances in bonding techniques have increased the range and scope for use of ceramics in dentistry. In this brief review, we will discuss advances in ceramic materials and fabrication techniques. Examples of the microstructure property relationships for these ceramic materials will also be addressed. PMID:21217946

  16. High resolution computed tomography of advanced composite and ceramic materials

    NASA Technical Reports Server (NTRS)

    Yancey, R. N.; Klima, S. J.

    1991-01-01

    Advanced composite and ceramic materials are being developed for use in many new defense and commercial applications. In order to achieve the desired mechanical properties of these materials, the structural elements must be carefully analyzed and engineered. A study was conducted to evaluate the use of high resolution computed tomography (CT) as a macrostructural analysis tool for advanced composite and ceramic materials. Several samples were scanned using a laboratory high resolution CT scanner. Samples were also destructively analyzed at the locations of the scans and the nondestructive and destructive results were compared. The study provides useful information outlining the strengths and limitations of this technique and the prospects for further research in this area.

  17. Elevated Temperature Testing and Modeling of Advanced Toughened Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Keith, Theo G.

    2005-01-01

    The purpose of this report is to provide a final report for the period of 12/1/03 through 11/30/04 for NASA Cooperative Agreement NCC3-776, entitled "Elevated Temperature Testing and Modeling of Advanced Toughened Ceramic Materials." During this final period, major efforts were focused on both the determination of mechanical properties of advanced ceramic materials and the development of mechanical test methodologies under several different programs of the NASA-Glenn. The important research activities made during this period are: 1. Mechanical properties evaluation of two gas-turbine grade silicon nitrides. 2) Mechanical testing for fuel-cell seal materials. 3) Mechanical properties evaluation of thermal barrier coatings and CFCCs and 4) Foreign object damage (FOD) testing.

  18. Fracture toughness of advanced ceramics at room temperature

    NASA Technical Reports Server (NTRS)

    Quinn, George D.; Salem, Jonathan; Bar-On, Isa; Cho, Kyu; Foley, Michael; Fang, HO

    1992-01-01

    Results of round-robin fracture toughness tests on advanced ceramics are reported. A gas-pressure silicon nitride and a zirconia-toughened alumina were tested using three test methods: indentation fracture, indentation strength, and single-edge precracked beam. The latter two methods have produced consistent results. The interpretation of fracture toughness test results for the zirconia alumina composite is shown to be complicated by R-curve and environmentally assisted crack growth phenomena.

  19. Fracture Toughness of Advanced Structural Ceramics: Applying ASTM C1421

    SciTech Connect

    Swab, Jeffrey J.; Tice, Jason; Wereszczak, Andrew A.; Kraft, Reuben H.

    2014-11-03

    The three methods of determining the quasi-static Mode I fracture toughness (KIc) (surface crack in flexure – SC, single-edge precracked beam – PB, and chevron notched beam – VB) found in ASTM C1421 were applied to a variety of advanced ceramic materials. All three methods produced valid and comparable KIc values for the Al2O3, SiC, Si3N4 and SiAlON ceramics examined. However, not all methods could successfully be applied to B4C, ZrO2 and WC ceramics due to a variety of material factors. The coarse-grained microstructure of one B4C hindered the ability to observe and measure the precracks generated in the SC and PB methods while the transformation toughening in the ZrO2 prevented the formation of the SC and PB precracks and thus made it impossible to use either method on this ceramic. The high strength and elastic modulus of the WC made it impossible to achieve stable crack growth using the VB method because the specimen stored a tremendous amount of energy prior to fracture. Even though these methods have passed the rigors of the standardization process there are still some issues to be resolved when the methods are applied to certain classes of ceramics. We recommend that at least two of these methods be employed to determine the KIc, especially when a new or unfamiliar ceramic is being evaluated.

  20. Development of impact design methods for ceramic gas turbine components

    NASA Technical Reports Server (NTRS)

    Song, J.; Cuccio, J.; Kington, H.

    1990-01-01

    Impact damage prediction methods are being developed to aid in the design of ceramic gas turbine engine components with improved impact resistance. Two impact damage modes were characterized: local, near the impact site, and structural, usually fast fracture away from the impact site. Local damage to Si3N4 impacted by Si3N4 spherical projectiles consists of ring and/or radial cracks around the impact point. In a mechanistic model being developed, impact damage is characterized as microcrack nucleation and propagation. The extent of damage is measured as volume fraction of microcracks. Model capability is demonstrated by simulating late impact tests. Structural failure is caused by tensile stress during impact exceeding material strength. The EPIC3 code was successfully used to predict blade structural failures in different size particle impacts on radial and axial blades.

  1. Fracture Toughness of Advanced Ceramics at Room Temperature.

    PubMed

    Quinn, George D; Salem, Jonathan; Bar-On, Isa; Cho, Kyu; Foley, Michael; Fang, Ho

    1992-01-01

    This report presents the results obtained by the five U.S. participating laboratories in the Versailles Advanced Materials and Standards (VAMAS) round-robin for fracture toughness of advanced ceramics. Three test methods were used: indentation fracture, indentation strength, and single-edge pre-cracked beam. Two materials were tested: a gas-pressure sintered silicon nitride and a zirconia toughened alumina. Consistent results were obtained with the latter two test methods. Interpretation of fracture toughness in the zirconia alumina composite was complicated by R-curve and environmentally-assisted crack growth phenomena.

  2. Fracture Toughness of Advanced Ceramics at Room Temperature

    PubMed Central

    Quinn, George D.; Salem, Jonathan; Bar-on, Isa; Cho, Kyu; Foley, Michael; Fang, Ho

    1992-01-01

    This report presents the results obtained by the five U.S. participating laboratories in the Versailles Advanced Materials and Standards (VAMAS) round-robin for fracture toughness of advanced ceramics. Three test methods were used: indentation fracture, indentation strength, and single-edge pre-cracked beam. Two materials were tested: a gas-pressure sintered silicon nitride and a zirconia toughened alumina. Consistent results were obtained with the latter two test methods. Interpretation of fracture toughness in the zirconia alumina composite was complicated by R-curve and environmentally-assisted crack growth phenomena. PMID:28053447

  3. Advanced Ceramics for NASA's Current and Future Needs

    NASA Technical Reports Server (NTRS)

    Jaskowiak, Martha H.

    2006-01-01

    Ceramic composites and monolithics are widely recognized by NASA as enabling materials for a variety of aerospace applications. Compared to traditional materials, ceramic materials offer higher specific strength which can enable lighter weight vehicle and engine concepts, increased payloads, and increased operational margins. Additionally, the higher temperature capabilities of these materials allows for increased operating temperatures within the engine and on the vehicle surfaces which can lead to improved engine efficiency and vehicle performance. To meet the requirements of the next generation of both rocket and air-breathing engines, NASA is actively pursuing the development and maturation of a variety of ceramic materials. Anticipated applications for carbide, nitride and oxide-based ceramics will be presented. The current status of these materials and needs for future goals will be outlined. NASA also understands the importance of teaming with other government agencies and industry to optimize these materials and advance them to the level of maturation needed for eventual vehicle and engine demonstrations. A number of successful partnering efforts with NASA and industry will be highlighted.

  4. Ceramic Integration Technologies for Advanced Energy Systems: Critical Needs, Technical Challenges, and Opportunities

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay

    2010-01-01

    Advanced ceramic integration technologies dramatically impact the energy landscape due to wide scale application of ceramics in all aspects of alternative energy production, storage, distribution, conservation, and efficiency. Examples include fuel cells, thermoelectrics, photovoltaics, gas turbine propulsion systems, distribution and transmission systems based on superconductors, nuclear power generation and waste disposal. Ceramic integration technologies play a key role in fabrication and manufacturing of large and complex shaped parts with multifunctional properties. However, the development of robust and reliable integrated systems with optimum performance requires the understanding of many thermochemical and thermomechanical factors, particularly for high temperature applications. In this presentation, various needs, challenges, and opportunities in design, fabrication, and testing of integrated similar (ceramic ceramic) and dissimilar (ceramic metal) material www.nasa.gov 45 ceramic-ceramic-systems have been discussed. Experimental results for bonding and integration of SiC based Micro-Electro-Mechanical-Systems (MEMS) LDI fuel injector and advanced ceramics and composites for gas turbine applications are presented.

  5. Parametric Weight Comparison of Advanced Metallic, Ceramic Tile, and Ceramic Blanket Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Myers, David E.; Martin, Carl J.; Blosser, Max L.

    2000-01-01

    A parametric weight assessment of advanced metallic panel, ceramic blanket, and ceramic tile thermal protection systems (TPS) was conducted using an implicit, one-dimensional (I-D) finite element sizing code. This sizing code contained models to account for coatings fasteners, adhesives, and strain isolation pads. Atmospheric entry heating profiles for two vehicles, the Access to Space (ATS) vehicle and a proposed Reusable Launch Vehicle (RLV), were used to ensure that the trends were not unique to a certain trajectory. Ten TPS concepts were compared for a range of applied heat loads and substructural heat capacities to identify general trends. This study found the blanket TPS concepts have the lightest weights over the majority of their applicable ranges, and current technology ceramic tiles and metallic TPS concepts have similar weights. A proposed, state-of-the-art metallic system which uses a higher temperature alloy and efficient multilayer insulation was predicted to be significantly lighter than the ceramic tile stems and approaches blanket TPS weights for higher integrated heat loads.

  6. "Ultra"-Fast Fracture Strength of Advanced Structural Ceramic Materials Studied at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.

    1999-01-01

    The accurate determination of inert strength is important in reliable life prediction of structural ceramic components. At ambient temperature, the inert strength of a brittle material is typically regarded as free of the effects of slow crack growth due to stress corrosion. Therefore, the inert strength can be determined either by eliminating active species, especially moisture, with an appropriate inert medium, or by using a very high test rate. However, at elevated temperatures, the concept or definition of the inert strength of brittle ceramic materials is not clear, since temperature itself is a degrading environment, resulting in strength degradation through slow crack growth and/or creep. Since the mechanism to control strength is rate-dependent viscous flow, the only conceivable way to determine the inert strength at elevated temperatures is to utilize a very fast test rate that either minimizes the time for or eliminates slow crack growth. Few experimental studies have measured the elevated-temperature, inert (or "ultra"-fast fracture) strength of advanced ceramics. At the NASA Lewis Research Center, an experimental study was initiated to better understand the "ultra"-fast fracture strength behavior of advanced ceramics at elevated temperatures. Fourteen advanced ceramics - one alumina, eleven silicon nitrides, and two silicon carbides - have been tested using constant stress-rate (dynamic fatigue) testing in flexure with a series of stress rates including the "ultra"-fast stress rate of 33 000 MPa/sec with digitally controlled test frames. The results for these 14 advanced ceramics indicate that, notwithstanding possible changes in flaw populations as well as flaw configurations because of elevated temperatures, the strength at 33 000 MPa/sec approached the room-temperature strength or reached a higher value than that determined at the conventional test rate of 30 MPa/sec. On the basis of the experimental data, it can be stated that the elevated

  7. Advanced Electrical Materials and Component Development

    NASA Technical Reports Server (NTRS)

    Schwarze, Gene E.

    2003-01-01

    The primary means to develop advanced electrical components is to develop new and improved materials for magnetic components (transformers, inductors, etc.), capacitors, and semiconductor switches and diodes. This paper will give a description and status of the internal and external research sponsored by NASA Glenn Research Center on soft magnetic materials, dielectric materials and capacitors, and high quality silicon carbide (SiC) atomically smooth substrates. The rationale for and the benefits of developing advanced electrical materials and components for the PMAD subsystem and also for the total power system will be briefly discussed.

  8. Evaluation of Sialon internal combustion engine components and fabrication of several ceramic components for automotive applications

    SciTech Connect

    McMurtry, C.H.; Ten Eyck, M.O.

    1992-10-01

    Fabrication development work was carried out on a push-rod tip having a stepped OD design and a 90[degree] shoulder in the transition area. Spray-dried Sialon premix was used in dry press tooling, and components were densified to about 98% of theoretical density using pressureless sintering conditions. Upon evaluation of the sintered components, it was found that afl components showed defects in the transition area. Modifications of the pressing parameters, incorporation of a 45[degree] angle in the shoulder area, and the use of tailored premix did not lead to the fabrication of defect-free parts. From these observations, it was concluded that the original part design could not easily be adapted to high-volume ceramic manufacturing methods. Subsequently, a modification to the desip was implemented. An SiC material with improved toughness (Hexoloy SX) was used for fabricating several test components with a closely machined, straight OD design. Pressureless-sintered and post-hot isostatically pressed (HIPed) Hexoloy SX components were supplied to The American Ceramic Engine Company (ACE) for assembly and testing. Fuel pump push-rod assemblies with Hemoloy SX tips were prepared by ACE, but no testing has been carried out to date.

  9. Evaluation of Sialon internal combustion engine components and fabrication of several ceramic components for automotive applications

    SciTech Connect

    McMurtry, C.H.; Ten Eyck, M.O.

    1992-10-01

    Fabrication development work was carried out on a push-rod tip having a stepped OD design and a 90{degree} shoulder in the transition area. Spray-dried Sialon premix was used in dry press tooling, and components were densified to about 98% of theoretical density using pressureless sintering conditions. Upon evaluation of the sintered components, it was found that afl components showed defects in the transition area. Modifications of the pressing parameters, incorporation of a 45{degree} angle in the shoulder area, and the use of tailored premix did not lead to the fabrication of defect-free parts. From these observations, it was concluded that the original part design could not easily be adapted to high-volume ceramic manufacturing methods. Subsequently, a modification to the desip was implemented. An SiC material with improved toughness (Hexoloy SX) was used for fabricating several test components with a closely machined, straight OD design. Pressureless-sintered and post-hot isostatically pressed (HIPed) Hexoloy SX components were supplied to The American Ceramic Engine Company (ACE) for assembly and testing. Fuel pump push-rod assemblies with Hemoloy SX tips were prepared by ACE, but no testing has been carried out to date.

  10. Robust Joining and Integration Technologies for Advanced Metallic, Ceramic, and Composite Systems

    NASA Technical Reports Server (NTRS)

    Singh, M.; Shpargel, Tarah; Morscher, Gregory N.; Halbig, Michael H.; Asthana, Rajiv

    2006-01-01

    Robust integration and assembly technologies are critical for the successful implementation of advanced metallic, ceramic, carbon-carbon, and ceramic matrix composite components in a wide variety of aerospace, space exploration, and ground based systems. Typically, the operating temperature of these components varies from few hundred to few thousand Kelvin with different working times (few minutes to years). The wide ranging system performance requirements necessitate the use of different integration technologies which includes adhesive bonding, low temperature soldering, active metal brazing, diffusion bonding, ARCJoinT, and ultra high temperature joining technologies. In this presentation, a number of joining examples and test results will be provided related to the adhesive bonding and active metal brazing of titanium to C/C composites, diffusion bonding of silicon carbide to silicon carbide using titanium interlayer, titanium and hastelloy brazing to silicon carbide matrix composites, and ARCJoinT joining of SiC ceramics and SiC matrix composites. Various issues in the joining of metal-ceramic systems including thermal expansion mismatch and resulting residual stresses generated during joining will be discussed. In addition, joint design and testing issues for a wide variety of joints will be presented.

  11. Nondestructive evaluation of advanced ceramic composite materials

    SciTech Connect

    Lott, L.A.; Kunerth, D.C.; Walter, J.B.

    1991-09-01

    Nondestructive evaluation techniques were developed to characterize performance degrading conditions in continuous fiber-reinforced silicon carbide/silicon carbide composites. Porosity, fiber-matrix interface bond strength, and physical damage were among the conditions studied. The material studied is formed by chemical vapor infiltration (CVI) of the matrix material into a preform of woven reinforcing fibers. Acoustic, ultrasonic, and vibration response techniques were studied. Porosity was investigated because of its inherent presence in the CVI process and of the resultant degradation of material strength. Correlations between porosity and ultrasonic attenuation and velocity were clearly demonstrated. The ability of ultrasonic transmission scanning techniques to map variations in porosity in a single sample was also demonstrated. The fiber-matrix interface bond was studied because of its importance in determining the fracture toughness of the material. Correlations between interface bonding and acoustic and ultrasonic properties were observed. These results are presented along with those obtained form acoustic and vibration response measurements on material samples subjected to mechanical impact damage. This is the final report on research sponsored by the US Department of Energy, Fossil Energy Advanced Research and Technology Development Materials Program. 10 refs., 24 figs., 2 tabs.

  12. Laser ablation of advanced ceramics and glass-ceramic materials: Reference position dependence

    NASA Astrophysics Data System (ADS)

    Sola, D.; Escartín, A.; Cases, R.; Peña, J. I.

    2011-04-01

    In this work, we present the effect produced by modifying the reference position as well as the method of machining on the results obtained when advanced ceramics and glass-ceramic materials are machined by laser ablation. A Q-switched Nd:YAG laser at its fundamental wavelength of 1064 nm with pulsewidths in the nanosecond range has been used. Morphology, depth and volume obtained by means of pulse bursts and grooves have been studied. Working within the same laser conditions, it has been shown that these values depend on the thermal, optical and mechanical features of the material processed. We have also studied the variation in the ablation yield when the position of the surface to be machined is modified. Material properties and work conditions are related to the results obtained. We have described and discussed the morphology, composition, microstructure and hardness of the materials processed.

  13. Pre-form ceramic matrix composite cavity and method of forming and method of forming a ceramic matrix composite component

    DOEpatents

    Monaghan, Philip Harold; Delvaux, John McConnell; Taxacher, Glenn Curtis

    2015-06-09

    A pre-form CMC cavity and method of forming pre-form CMC cavity for a ceramic matrix component includes providing a mandrel, applying a base ply to the mandrel, laying-up at least one CMC ply on the base ply, removing the mandrel, and densifying the base ply and the at least one CMC ply. The remaining densified base ply and at least one CMC ply form a ceramic matrix component having a desired geometry and a cavity formed therein. Also provided is a method of forming a CMC component.

  14. Advanced Electrical Materials and Components Being Developed

    NASA Technical Reports Server (NTRS)

    Schwarze, Gene E.

    2004-01-01

    All aerospace systems require power management and distribution (PMAD) between the energy and power source and the loads. The PMAD subsystem can be broadly described as the conditioning and control of unregulated power from the energy source and its transmission to a power bus for distribution to the intended loads. All power and control circuits for PMAD require electrical components for switching, energy storage, voltage-to-current transformation, filtering, regulation, protection, and isolation. Advanced electrical materials and component development technology is a key technology to increasing the power density, efficiency, reliability, and operating temperature of the PMAD. The primary means to develop advanced electrical components is to develop new and/or significantly improved electronic materials for capacitors, magnetic components, and semiconductor switches and diodes. The next important step is to develop the processing techniques to fabricate electrical and electronic components that exceed the specifications of presently available state-of-the-art components. The NASA Glenn Research Center's advanced electrical materials and component development technology task is focused on the following three areas: 1) New and/or improved dielectric materials for the development of power capacitors with increased capacitance volumetric efficiency, energy density, and operating temperature; 2) New and/or improved high-frequency, high-temperature soft magnetic materials for the development of transformers and inductors with increased power density, energy density, electrical efficiency, and operating temperature; 3) Packaged high-temperature, high-power density, high-voltage, and low-loss SiC diodes and switches.

  15. Ceramic automotive Stirling engine program

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The Ceramic Automotive Stirling Engine Program evaluated the application of advanced ceramic materials to an automotive Stirling engine. The objective of the program was to evaluate the technical feasibility of utilizing advanced ceramics to increase peak engine operating temperature, and to evaluate the performance benefits of such an increase. Manufacturing cost estimates were also developed for various ceramic engine components and compared with conventional metallic engine component costs.

  16. Ceramic Automotive Stirling Engine Program

    SciTech Connect

    Not Available

    1986-08-01

    The Ceramic Automotive Stirling Engine Program evaluated the application of advanced ceramic materials to an automotive Stirling engine. The objective of the program was to evaluate the technical feasibility of utilizing advanced ceramics to increase peak engine operating temperature, and to evaluate the performance benefits of such an increase. Manufacturing cost estimates were also developed for various ceramic engine components and compared with conventional metallic engine component costs.

  17. Physics-Based Design Tools for Lightweight Ceramic Composite Turbine Components with Durable Microstructures

    NASA Technical Reports Server (NTRS)

    DiCarlo, James A.

    2011-01-01

    Under the Supersonics Project of the NASA Fundamental Aeronautics Program, modeling and experimental efforts are underway to develop generic physics-based tools to better implement lightweight ceramic matrix composites into supersonic engine components and to assure sufficient durability for these components in the engine environment. These activities, which have a crosscutting aspect for other areas of the Fundamental Aero program, are focusing primarily on improving the multi-directional design strength and rupture strength of high-performance SiC/SiC composites by advanced fiber architecture design. This presentation discusses progress in tool development with particular focus on the use of 2.5D-woven architectures and state-of-the-art constituents for a generic un-cooled SiC/SiC low-pressure turbine blade.

  18. Ceramics in engine components. (Latest citations from Engineered Materials abstracts). Published Search

    SciTech Connect

    1995-12-01

    The bibliography contains citations concerning the application of ceramics in automotive and aerospace engine components. Mechanical properties are reviewed. The citations examine techniques for joining dissimilar materials, advantages and problems associated with substitutions of ceramics in lieu of metals, and types and methods of ceramic coatings.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  19. 0-G experiments with advanced ceramic fabric wick structures

    SciTech Connect

    Antoniak, Z.I.; Webb, B.J.; Bates, J.M.; Cooper, M.F.; Pauley, K.A.

    1991-07-01

    Both Air Force and NASA future spacecraft thermal management needs span the temperature range from cryogenic to liquid metals. Many of these needs are changing and not well defined and will remain so until goals, technology, and missions converge. Nevertheless, it is certain that high-temperature (> 800 K) and medium-temperature (about 450 K) radiator systems will have to be developed that offer significant improvements over current designs. This paper discusses experiments performed in the lower temperature regime as part of a comprehensive advanced ceramic fabric (ACF) heat pipe development program. These experiments encompassed wicking tests with various ceramic fabric samples, and heat transfer tests with a 1-m long prototype ACF water heat pipe. A prototype ceramic fabric/titanium water heat pipe has been constructed and tested; it transported up to 60 W of power at about 390 K. Startup and operation both with and against gravity examined. Wick testing was begun to aid in the design and construction of an improved prototype heat pipe, with a 38-{mu}m stainless steel linear covered by a biaxially-braided Nextel (trademark of the 3M Co., St. Paul, Minnesota) sleeve that is approximately 300-{mu}m thick. Wick testing took place in 1-g; limited testing in 0-g was initiated, and results to date suggest that in 0-g, wick performance improves over that in 1-g.

  20. Application of scanning acoustic microscopy to advanced structural ceramics

    NASA Technical Reports Server (NTRS)

    Vary, Alex; Klima, Stanley J.

    1987-01-01

    A review is presentod of research investigations of several acoustic microscopy techniques for application to structural ceramics for advanced heat engines. Results obtained with scanning acoustic microscopy (SAM), scanning laser acoustic microscopy (SLAM), scanning electron acoustic microscopy (SEAM), and photoacoustic microscopy (PAM) are compared. The techniques were evaluated on research samples of green and sintered monolithic silicon nitrides and silicon carbides in the form of modulus-of-rupture bars containing deliberately introduced flaws. Strengths and limitations of the techniques are described with emphasis on statistics of detectability of flaws that constitute potential fracture origins.

  1. Ultrasonic and radiographic evaluation of advanced aerospace materials: Ceramic composites

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1990-01-01

    Two conventional nondestructive evaluation techniques were used to evaluate advanced ceramic composite materials. It was shown that neither ultrasonic C-scan nor radiographic imaging can individually provide sufficient data for an accurate nondestructive evaluation. Both ultrasonic C-scan and conventional radiographic imaging are required for preliminary evaluation of these complex systems. The material variations that were identified by these two techniques are porosity, delaminations, bond quality between laminae, fiber alignment, fiber registration, fiber parallelism, and processing density flaws. The degree of bonding between fiber and matrix cannot be determined by either of these methods. An alternative ultrasonic technique, angular power spectrum scanning (APSS) is recommended for quantification of this interfacial bond.

  2. Creep Life of Ceramic Components Using a Finite-Element-Based Integrated Design Program (CARES/CREEP)

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, J. P.; Powers, L. M.; Jadaan, O. M.

    1998-01-01

    The desirable properties of ceramics at high temperatures have generated interest in their use for structural applications such as in advanced turbine systems. Design lives for such systems can exceed 10,000 hours. The long life requirement necessitates subjecting the components to relatively low stresses. The combination of high temperatures and low stresses typically places failure for monolithic ceramics in the creep regime. The objective of this paper is to present a design methodology for predicting the lifetimes of structural components subjected to creep rupture conditions. This methodology utilized commercially available finite element packages and takes into account the time-varying creep strain distributions (stress relaxation). The creep life of a component is discretized into short time steps, during which the stress and strain distributions are assumed constant. The damage is calculated for each time step based on a modified Monkman-Grant creep rupture criterion. Failure is assumed to occur when the normalized accumulated damage at any point in the component is greater than or equal to unity. The corresponding time will be the creep rupture life for that component. Examples are chosen to demonstrate the CARES/CREEP (Ceramics Analysis and Reliability Evaluation of Structures/CREEP) integrated design programs, which is written for the ANSYS finite element package. Depending on the component size and loading conditions, it was found that in real structures one of two competing failure modes (creep or slow crack growth) will dominate. Applications to benechmark problems and engine components are included.

  3. Creep Life of Ceramic Components Using a Finite-Element-Based Integrated Design Program (CARES/CREEP)

    NASA Technical Reports Server (NTRS)

    Powers, L. M.; Jadaan, O. M.; Gyekenyesi, J. P.

    1998-01-01

    The desirable properties of ceramics at high temperatures have generated interest in their use for structural application such as in advanced turbine engine systems. Design lives for such systems can exceed 10,000 hours. The long life requirement necessitates subjecting the components to relatively low stresses. The combination of high temperatures and low stresses typically places failure for monolithic ceramics in the creep regime. The objective of this paper is to present a design methodology for predicting the lifetimes of structural components subjected to creep rupture conditions. This methodology utilizes commercially available finite element packages and takes into account the time-varying creep strain distributions (stress relaxation). The creep life, of a component is discretized into short time steps, during which the stress and strain distributions are assumed constant. The damage is calculated for each time step based on a modified Monkman-Grant creep rupture criterion. Failure is assumed to occur when the normalized accumulated damage at any point in the component is greater than or equal to unity. The corresponding time will be the creep rupture life for that component. Examples are chosen to demonstrate the Ceramics Analysis and Reliability Evaluation of Structures/CREEP (CARES/CREEP) integrated design program, which is written for the ANSYS finite element package. Depending on the component size and loading conditions, it was found that in real structures one of two competing failure modes (creep or slow crack growth) will dominate. Applications to benchmark problems and engine components are included.

  4. Advanced Placement: Model Policy Components. Policy Analysis

    ERIC Educational Resources Information Center

    Zinth, Jennifer

    2016-01-01

    Advanced Placement (AP), launched in 1955 by the College Board as a program to offer gifted high school students the opportunity to complete entry-level college coursework, has since expanded to encourage a broader array of students to tackle challenging content. This Education Commission of the State's Policy Analysis identifies key components of…

  5. New engine and advanced component design

    SciTech Connect

    Not Available

    1990-01-01

    This book contains the proceedings on new engine and advance component design. Topics covered include: development of low emission high performance four valve engines, the effect of engine build options on powerplant inertias, silicon nitride turbocharger rotor for high performance automotive engines and development of Toyota reflex Burn (TRB) system in DI diesel.

  6. Assessing condition of turbine engine ceramic components through NDE technology.

    SciTech Connect

    Ellingson, W.A.; Sun, J.G.; Deemer, C.; Erdman, S.; Prested, C.

    2002-04-12

    Thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) are under development for hot-gas path components to allow higher gas-firing temperatures in advanced (high-efficiency, low-emission) gas turbines. Increasing dependence on the reliability of TBC and EBC components has driven the need for nondestructive evaluation (NDE) methods to assess the condition, or ''health status,'' of these coatings. NDE methods based on elastic optical scatter and thermal imaging have been applied to TBC-coated test specimens that were thermally cycled and to EBC-coated SiC/SiC components that were run in 4.5 MW(e) field-test turbines. One primary interest is to develop NDE methods that can predict a prespall condition. Resulting data suggest a correlation between laser scatter data and thermal cycles for TBC-coated specimens, and thermal imaging results have demonstrated prespall detection for an EBC-coated SiC/SiC combustor liner.

  7. Analysis of the low temperature ceramics structure with consideration for polydispersity of initial refractory components

    NASA Astrophysics Data System (ADS)

    Leytsin, Vladimir N.; Dmitrieva, Mariya A.; Tovpinets, Alexandr O.; Ivonin, Ivan V.; Ponomarev, Sergey V.

    2016-11-01

    The results of computer simulation of the structure and physical properties of sintered low-temperature ceramics specimens with different volume fractions of different components of refractory components are presented. Properties of sintered ceramics, residual porosity, and shrinkage anisotropy are determined by features of packing of various fractions of refractory particles. The results indicate the determining factor of the presence of particles of the coarse fraction of refractory components capable of forming a internal skeleton of interacting particles.

  8. Advanced ceramic material for high temperature turbine tip seals

    NASA Technical Reports Server (NTRS)

    Solomon, N. G.; Vogan, J. W.

    1978-01-01

    Ceramic material systems are being considered for potential use as turbine blade tip gas path seals at temperatures up to 1370 1/4 C. Silicon carbide and silicon nitride structures were selected for study since an initial analysis of the problem gave these materials the greatest potential for development into a successful materials system. Segments of silicon nitride and silicon carbide materials over a range of densities, processed by various methods, a honeycomb structure of silicon nitride and ceramic blade tip inserts fabricated from both materials by hot pressing were tested singly and in combination. The evaluations included wear under simulated engine blade tip rub conditions, thermal stability, impact resistance, machinability, hot gas erosion and feasibility of fabrication into engine components. The silicon nitride honeycomb and low-density silicon carbide using a selected grain size distribution gave the most promising results as rub-tolerant shroud liners. Ceramic blade tip inserts made from hot-pressed silicon nitride gave excellent test results. Their behavior closely simulated metal tips. Wear was similar to that of metals but reduced by a factor of six.

  9. Development of ASTM standards in support of advanced ceramics -- continuing efforts

    SciTech Connect

    Brinkman, C.R.

    1998-02-01

    An update is presented of the activities of the American Society for Testing and Materials (ASTM) Committee C-28 on Advanced Ceramics. Since its inception in 1986, this committee, which has five standard producing subcommittees, has written and published over 32 consensus standards. These standards are concerned with mechanical testing of monolithic and composite ceramics, nondestructive examination, statistical analysis and design, powder characterization, quantitative microscopy, fractography, and terminology. These standards ensure optimum material behavior with physical and mechanical property reproducibility, component reliability, and well-defined methods of data treatment and material analysis for both monolithic and composite materials. Committee C-28 continues to sponsor technical symposia and to cooperate in the development of international standards. An update of recent and current activities as well as possible new areas of standardization work will be presented.

  10. Study and program plan for improved heavy duty gas turbine engine ceramic component development

    NASA Technical Reports Server (NTRS)

    Helms, H. E.

    1977-01-01

    Fuel economy in a commercially viable gas turbine engine was demonstrated through use of ceramic materials. Study results show that increased turbine inlet and generator inlet temperatures, through the use of ceramic materials, contribute the greatest amount to achieving fuel economy goals. Improved component efficiencies show significant additional gains in fuel economy.

  11. Method for removing volatile components from a ceramic article, and related processes

    DOEpatents

    Klug, Frederic Joseph; DeCarr, Sylvia Marie

    2002-01-01

    A method of removing substantially all of the volatile component in a green, volatile-containing ceramic article is disclosed. The method comprises freezing the ceramic article; and then subjecting the frozen article to a vacuum for a sufficient time to freeze-dry the article. Frequently, the article is heated while being freeze-dried. Use of this method efficiently reduces the propensity for any warpage of the article. The article is often formed from a ceramic slurry in a gel-casting process. A method for fabricating a ceramic core used in investment casting is also described.

  12. Method For Removing Volatile Components From A Gel-Cast Ceramic Article

    DOEpatents

    Klug, Frederic Joseph; DeCarr, Sylvia Marie

    2004-09-07

    A method of removing substantially all of the volatile component in a green, volatile-containing ceramic article is disclosed. The method comprises freezing the ceramic article; and then subjecting the frozen article to a vacuum for a sufficient time to freeze-dry the article. Frequently, the article is heated while being freeze-dried. Use of this method efficiently reduces the propensity for any warpage of the article. The article is often formed from a ceramic slurry in a gel-casting process. A method for fabricating a ceramic core used in investment casting is also described.

  13. Thermal response of ceramic components during electron beam brazing

    SciTech Connect

    Voth, T.E.; Gianoulakis, S.E.; Halbleib, J.A.

    1996-03-01

    Ceramics are being used increasingly in applications where high temperatures are encountered such as automobile and gas turbine engines. However, the use of ceramics is limited by a lack of methods capable of producing strong, high temperature joints. This is because most ceramic-ceramic joining techniques, such as brazing, require that the entire assembly be exposed to high temperatures in order to assure that the braze material melts. Alternatively, localized heating using high energy electron beams may be used to selectively heat the braze material. In this work, high energy electron beam brazing of a ceramic part is modeled numerically. The part considered consists of a ceramic cylinder and disk between which is sandwiched an annular washer of braze material. An electron beam impinges on the disk, melting the braze metal. The resulting coupled electron and thermal transport equations are solved using Monte Carlo and finite element techniques. Results indicate that increased electron beam current decreases time to melt as well as required cooling time. Vacuum furnace brazing was also simulated and predicted results indicate increased processing times relative to electron beam brazing.

  14. Advanced processing of the Zerodur R glass ceramic

    NASA Astrophysics Data System (ADS)

    Marx, Thomas A.

    1991-11-01

    The Zerodur glass ceramic is an extraordinary material possessing a very low thermal expansion over a broad temperature range. Depending on the size of the castings, a continuous or a discontinuous melting technology is used in the manufacture of Zerodur. Continuous melters are being operated regularly in Germany and recently in the United States. The latest generation of discontinuous melters started production of 8.2 m spincast telescope blanks in early 1991. Zerodur fusion is a special process to generate lightweighted mirror blanks and special components. It requires glassy material and generates bonds that are as strong as the bulk material. Further process development such as waterjet cutting and insertion technologies are underway and may generate components of unique shapes and performance.

  15. Analysis of whisker-toughened ceramic components: A design engineer's viewpoint

    NASA Technical Reports Server (NTRS)

    Duffy, Stephen F.; Manderscheid, Jane M.; Palko, Joseph L.

    1989-01-01

    The use of ceramics components in gas turbines, cutting tools, and heat exchangers has been limited by the relatively low flaw tolerance of monolithic ceramics. The development of whisker toughened ceramic composites offers the potential for considerable improvement in fracture toughness as well as strength. However, the variability of strength is still too high for the application of deterministic design approaches. Several phenomenological reliability theories proposed for this material system are reviewed and the development is reported of a public domain computer algorithm. This algorithm, when coupled with a general purpose finite element program, predicts the fast fracture reliability of a structural component under multiaxial loading conditions.

  16. Liquid-assisted laser ablation of advanced ceramics and glass-ceramic materials

    NASA Astrophysics Data System (ADS)

    Garcia-Giron, A.; Sola, D.; Peña, J. I.

    2016-02-01

    In this work, results obtained by laser ablation of advanced ceramics and glass-ceramic materials assisted by liquids are reported. A Q-switched Nd:YAG laser at its fundamental wavelength of 1064 nm with pulse-width in the nanosecond range was used to machine the materials, which were immersed in water and ethylene glycol. Variation in geometrical parameters, morphology, and ablation yields were studied by using the same laser working conditions. It was observed that machined depth and removed volume depended on the thermal, optical, and mechanical features of the processed materials as well as on the properties of the surrounding medium in which the laser processing was carried out. Variation in ablation yields was studied in function of the liquid used to assist the laser process and related to refractive index and viscosity. Material features and working conditions were also related to the obtained results in order to correlate ablation parameters with respect to the hardness of the processed materials.

  17. Investigation of properties and performance of ceramic composite components: Final report on Phases 3 and 4

    SciTech Connect

    Curtin, W.A.; Halverson, H.; Carter, R.H.; Miraj, N.; Reifsnider, K.L.

    1998-01-15

    The objective of the Fossil Energy Advanced Research and Technology Development (AR and TD) Materials Program is to conduct research and development on materials for longer-term fossil energy applications as well as for generic needs of various fossil fuel technologies. The research program of the Materials Response Group at Virginia Tech addresses the need for reliable and durable structural ceramic composites to perform in high temperature environments. The research effort provides an experimental and analytical basis for the transition from properties of materials to performance of actual component structures. Phases 1 and 2 of the present program focused on the development of test capabilities, initial studies of component mechanical response under various conditions and the development of a life prediction methodology. These efforts have been described in previous reports. This report summarizes the major tasks completed under Phases 3 and 4 of the project. Overall, the authors have made significant progress in a broad spectrum of tasks in this program. Their efforts have encompassed component evaluation, assessment of new SiC-based composites with improved high-temperature potential, development of oxide coating materials for SiC, and the extension and development of new models for predicting the durability of composite components under specific operating conditions for various CMC applications. Each of these areas of work is an important area for achieving the ultimate goal of usable SiC-based composites in high-temperature corrosive environments typical of fossil energy applications.

  18. NDE of advanced turbine engine components and materials by computed tomography

    NASA Technical Reports Server (NTRS)

    Yancey, R. N.; Baaklini, George Y.; Klima, Stanley J.

    1991-01-01

    Computed tomography (CT) is an X-ray technique that provides quantitative 3D density information of materials and components and can accurately detail spatial distributions of cracks, voids, and density variations. CT scans of ceramic materials, composites, and engine components were taken and the resulting images will be discussed. Scans were taken with two CT systems with different spatial resolution capabilities. The scans showed internal damage, density variations, and geometrical arrangement of various features in the materials and components. It was concluded that CT can play an important role in the characterization of advanced turbine engine materials and components. Future applications of this technology will be outlined.

  19. Dynamic Behavior and Optimization of Advanced Armor Ceramics: January-December 2012 Annual Report

    DTIC Science & Technology

    2015-03-01

    properties. Since the rapid heating process avoids many of the negative attributes of traditional B4C synthesis , such as the presence of unreacted C...References Weimer A, Moore W, Roach R, Hitt J, Dixit R, Pratsinis S. Kinetics of carbothermal reduction synthesis of boron carbide. J Am Ceram Soc. 1992;75...9):2509. Knudsen A. Laser-driven synthesis and densification of ultrafine boron carbide powders. Advances in Ceramics: Ceramic Powder Science

  20. Lifetime predictions for alumina ceramics used in nuclear weapons stockpile components

    SciTech Connect

    Glass, S.J.; Monroe, S.L.; Newton, C.

    1997-09-01

    Ceramic materials are used extensively in non-nuclear components in the weapons stockpile including neutron tubes, firing sets, radar, strong link and weak link assemblies, batteries, and current/voltage stacks. Ceramics also perform critical functions in electronics, passively as insulators and actively as resistors and capacitors. Glass and ceramic seals also provide hermetic electrical feedthroughs in connectors for many weapons components. The primary goal of the ceramic material lifetime prediction program is to provide the enhanced surveillance program with the capability to specify the reliability and lifetimes of glass and ceramic-containing components under conditions typical of the stockpile environment. The authors have studied the reliability and subcritical crack growth (SCG) behavior of 94% alumina (Al{sub 2}O{sub 3}), which is likely the most common ceramic in the stockpile. Measurements have been made on aluminas manufactured by four war reserve qualified vendors (Coors, Wesgo, AlSiMag, and Diamonite). These materials are expected to be representative of typical product obtained from vendors who have supplied alumina for weapons components during the past several decades.

  1. Ceramic applications in turbine engines. [for improved component performance and reduced fuel usage

    NASA Technical Reports Server (NTRS)

    Hudson, M. S.; Janovicz, M. A.; Rockwood, F. A.

    1980-01-01

    Ceramic material characterization and testing of ceramic nozzle vanes, turbine tip shrouds, and regenerators disks at 36 C above the baseline engine TIT and the design, analysis, fabrication and development activities are described. The design of ceramic components for the next generation engine to be operated at 2070 F was completed. Coupons simulating the critical 2070 F rotor blade was hot spin tested for failure with sufficient margin to quality sintered silicon nitride and sintered silicon carbide, validating both the attachment design and finite element strength. Progress made in increasing strength, minimizing variability, and developing nondestructive evaluation techniques is reported.

  2. Probabilistic Evaluation of Advanced Ceramic Matrix Composite Structures

    NASA Technical Reports Server (NTRS)

    Abumeri, Galib H.; Chamis, Christos C.

    2003-01-01

    The objective of this report is to summarize the deterministic and probabilistic structural evaluation results of two structures made with advanced ceramic composites (CMC): internally pressurized tube and uniformly loaded flange. The deterministic structural evaluation includes stress, displacement, and buckling analyses. It is carried out using the finite element code MHOST, developed for the 3-D inelastic analysis of structures that are made with advanced materials. The probabilistic evaluation is performed using the integrated probabilistic assessment of composite structures computer code IPACS. The affects of uncertainties in primitive variables related to the material, fabrication process, and loadings on the material property and structural response behavior are quantified. The primitive variables considered are: thermo-mechanical properties of fiber and matrix, fiber and void volume ratios, use temperature, and pressure. The probabilistic structural analysis and probabilistic strength results are used by IPACS to perform reliability and risk evaluation of the two structures. The results will show that the sensitivity information obtained for the two composite structures from the computational simulation can be used to alter the design process to meet desired service requirements. In addition to detailed probabilistic analysis of the two structures, the following were performed specifically on the CMC tube: (1) predicted the failure load and the buckling load, (2) performed coupled non-deterministic multi-disciplinary structural analysis, and (3) demonstrated that probabilistic sensitivities can be used to select a reduced set of design variables for optimization.

  3. Microstructurally tailored ceramics for advanced energy applications by thermoreversible gelcasting

    NASA Astrophysics Data System (ADS)

    Shanti, Noah Omar

    Thermoreversible gelcasting (TRG) is an advantageous technique for rapidly producing bulk, net-shape ceramics and laminates. In this method, ceramic powder is suspended in warm acrylate triblock copolymer/alcohol solutions that reversibly gel upon cooling by the formation of endblock aggregates, to produce slurries which are cast into molds. Gel properties can be tailored by controlling the endblock and midblock lengths of the copolymer network-former and selecting an appropriate alcohol solvent. This research focuses on expanding and improving TRG techniques, focusing specifically on advanced energy applications including the solid oxide fuel cell (SOFC). Rapid drying of filled gels can lead to warping and cracking caused by high differential capillary stresses. A new drying technique using concentrated, alcohol-based solutions as liquid desiccants (LDs) to greatly reduce warping is introduced. The optimal LD is a poly(tert-butyl acrylate)/isopropyl alcohol solution with 5 mol% tert-butyl acrylate units. Alcohol emissions during drying are completely eliminated by combining initial drying in an LD with final stage drying in a vacuum oven having an in-line solvent trap. Porous ceramics are important structures for many applications, including SOFCs. Pore network geometries are tailored by the addition of fugitive fillers to TRG slurries. Uniform spherical, bimodal spherical and uniform fibrous fillers are used. Three-dimensional pore structures are visualized by X-ray computed tomography, allowing for direct measurements of physical parameters such as concentration and morphology as well as transport properties such as tortuosity. Tortuosity values as low as 1.52 are achieved when 60 vol% of solids are uniform spherical filler. Functionally graded laminates with layers ranging from 10 mum to > 1 mm thick are produced with a new technique that combines TRG with tape casting. Gels used for bulk casting are not suitable for use with tape casting, and appropriate base

  4. Inspecting Composite Ceramic Armor Using Advanced Signal Processing Together with Phased Array Ultrasound

    DTIC Science & Technology

    2010-01-08

    processing techniques have been developed to help improve phased array ultrasonic inspection and analysis of multi-layered ceramic armor panels. The...INSPECTING COMPOSITE CERAMIC ARMOR USING ADVANCED SIGNAL PROCESSING TOGETHER WITH PHASED ARRAY ULTRASOUND J. S. Steckenrider Illinois College...immersion phased array ultrasound system. Some of these specimens had intentional design defects inserted interior to the specimens. Because of the very

  5. The status of ceramic turbine component fabrication and quality assurance relevant to automotive turbine needs

    SciTech Connect

    Richerson, D.W.

    2000-02-01

    This report documents a study funded by the U.S. Department of Energy (DOE) Office of Transportation Technologies (OTT) with guidance from the Ceramics Division of the United States Automotive Materials Partnership (USAMP). DOE and the automotive companies have funded extensive development of ceramic materials for automotive gas turbine components, the most recent effort being under the Partnership for a New Generation of Vehicles (PNGV) program.

  6. The development and testing of ceramic components in piston engines. Final report

    SciTech Connect

    McEntire, B.J.; Willis, R.W.; Southam, R.E.

    1994-10-01

    Within the past 10--15 years, ceramic hardware has been fabricated and tested in a number of piston engine applications including valves, piston pins, roller followers, tappet shims, and other wear components. It has been shown that, with proper design and installation, ceramics improve performance, fuel economy, and wear and corrosion resistance. These results have been obtained using rig and road tests on both stock and race engines. Selected summaries of these tests are presented in this review paper.

  7. Optimal glass-ceramic structures: Components of giant mirror telescopes

    NASA Technical Reports Server (NTRS)

    Eschenauer, Hans A.

    1990-01-01

    Detailed investigations are carried out on optimal glass-ceramic mirror structures of terrestrial space technology (optical telescopes). In order to find an optimum design, a nonlinear multi-criteria optimization problem is formulated. 'Minimum deformation' at 'minimum weight' are selected as contradictory objectives, and a set of further constraints (quilting effect, optical faults etc.) is defined and included. A special result of the investigations is described.

  8. Methods for providing ceramic matrix composite components with increased thermal capacity

    NASA Technical Reports Server (NTRS)

    Steibel, James Dale (Inventor); Utah, David Alan (Inventor)

    2001-01-01

    A method for enhancing the cooling capability of a turbine component made from a ceramic matrix composite. The method improves the thermal performance of the component by producing a surface having increased cooling capacity, thereby allowing the component to operate at a higher temperature. The method tailors the available surface area on the cooling surface of the composite component by depositing a particulate layer of coarse grained ceramic powders of preselected size onto the surface of the ceramic matrix composite component. The size of the particulate is selectively tailored to match the desired surface finish or surface roughness of the article. The article may be designed to have different surface finishes for different locations, so that the application of different sized powders can provide different cooling capabilities at different locations, if desired. The compositions of the particulates are chemically compatible with the ceramic material comprising the outer surface or portion of the ceramic matrix composite. The particulates are applied using a slurry and incorporated into the article by heating to an elevated temperature without melting the matrix, the particulates or the fiber reinforcement.

  9. Advanced Environmental Barrier Coating Development for SiC/SiC Ceramic Matrix Composites: NASA's Perspectives

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming

    2016-01-01

    This presentation reviews NASA environmental barrier coating (EBC) system development programs and the coating materials evolutions for protecting the SiC/SiC Ceramic Matrix Composites in order to meet the next generation engine performance requirements. The presentation focuses on several generations of NASA EBC systems, EBC-CMC component system technologies for SiC/SiC ceramic matrix composite combustors and turbine airfoils, highlighting the temperature capability and durability improvements in simulated engine high heat flux, high pressure, high velocity, and with mechanical creep and fatigue loading conditions. The current EBC development emphasis is placed on advanced NASA 2700F candidate environmental barrier coating systems for SiC/SiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. Major technical barriers in developing environmental barrier coating systems, the coating integrations with next generation CMCs having the improved environmental stability, erosion-impact resistance, and long-term fatigue-environment system durability performance are described. The research and development opportunities for advanced turbine airfoil environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling are discussed.

  10. Melt Infiltrated Ceramic Matrix Composites for Shrouds and Combustor Liners of Advanced Industrial Gas Turbines

    SciTech Connect

    Gregory Corman; Krishan Luthra; Jill Jonkowski; Joseph Mavec; Paul Bakke; Debbie Haught; Merrill Smith

    2011-01-07

    This report covers work performed under the Advanced Materials for Advanced Industrial Gas Turbines (AMAIGT) program by GE Global Research and its collaborators from 2000 through 2010. A first stage shroud for a 7FA-class gas turbine engine utilizing HiPerComp{reg_sign}* ceramic matrix composite (CMC) material was developed. The design, fabrication, rig testing and engine testing of this shroud system are described. Through two field engine tests, the latter of which is still in progress at a Jacksonville Electric Authority generating station, the robustness of the CMC material and the shroud system in general were demonstrated, with shrouds having accumulated nearly 7,000 hours of field engine testing at the conclusion of the program. During the latter test the engine performance benefits from utilizing CMC shrouds were verified. Similar development of a CMC combustor liner design for a 7FA-class engine is also described. The feasibility of using the HiPerComp{reg_sign} CMC material for combustor liner applications was demonstrated in a Solar Turbines Ceramic Stationary Gas Turbine (CSGT) engine test where the liner performed without incident for 12,822 hours. The deposition processes for applying environmental barrier coatings to the CMC components were also developed, and the performance of the coatings in the rig and engine tests is described.

  11. Assessment of Japanese Technology in Advanced Glass and Ceramic Fibers

    DTIC Science & Technology

    1992-06-01

    3 International Symposium on the Science of Engineering Ceramics, Mikawa-Haitsu, Koda, 21 Through 23 October 1991...for armor and heat engine applications. While the importance of the matrix cannot be ignored, the fiber or whisker phases used in making composites...contemporary activities in ceramics in Japan. International Symposium on the Science of Engineering Ceramics, Mlkawa-Haltsu, Koda, 21 Through 23 October

  12. Sonogels in the Preparation of Advanced Glass and Ceramic Materials

    DTIC Science & Technology

    1992-10-20

    1 In0 f 7;ra Products) ceramic fibres . -using other yreinforcing phases in the. form of 7’T02 (7YF- 100 ,Zircar Products) and A1203 (MAFTEC) ceramic...usd we -r, made friom ceramic fibres . In both cases t ,- fi bris were I anrgel y continuous and random], oriented in p1lanes parallel Io tahe layers...gives the relative densities for the CT15 ’ A1203 composites . They are designated as CT15Av , where y is the volume fract ion of alt]mina ceramic

  13. Experimental assessment of advanced Stirling component concepts

    NASA Technical Reports Server (NTRS)

    Ziph, B.

    1985-01-01

    The results of an experimental assessment of some advanced Stirling engine component concepts are presented. High performance piston rings, reciprocating oil scrapers and heat pipes with getters and with mechanical couplings were tested. The tests yielded the following results: (1) Bonded, split, pumping piston rings, in preliminary testing, proved a promising concept, exhibiting low leakage and friction losses. Solid piston rings proved impractical in view of their sensitivity to the operating temperature; (2) A babbit oil scraper in a compliant housing performed well in atmospheric endurance testing. In pressurized tests the scraper did not perform well as a containment seal. The latter tests suggest modifications which may adapt Ti successfully to that application; and (3) Heat pipe endurance tests indicated the adequacy of simple, inexpensive fabrication and filling procedures. Getters were provided to increase the tolerance of the heat pipes to the presence of air and commercially available couplings were demonstrated to be suitable for heat pipe application. In addition to the above tests, the program also included a design effort for a split shaft applicable to a swashplate driven engine with a pressurized crank-case. The design is aimed, and does accomplish, an increase in component life to more than 10,000 hours.

  14. Innovative grinding wheel design for cost-effective machining of advanced ceramics

    SciTech Connect

    Licht, R.H.; Kuo, P.; Liu, S.; Murphy, D.; Picone, J.W.; Ramanath, S.

    2000-05-01

    This Final Report covers the Phase II Innovative Grinding Wheel (IGW) program in which Norton Company successfully developed a novel grinding wheel for cost-effective cylindrical grinding of advanced ceramics. In 1995, Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics using small prototype wheels. The Phase II program was initiated to scale-up the new superabrasive wheel specification to larger diameters, 305-mm to 406-mm, required for most production grinding of cylindrical ceramic parts, and to perform in-house and independent validation grinding tests.

  15. Fracture behavior of advanced ceramic hot gas filters: Final report

    SciTech Connect

    Singh, J.P.; Majumdar, S.; Sutaria, M.; Bielke, W.

    1997-03-01

    This report presents the results of mechanical/microstructural evaluation, thermal shock/fatigue testing, and stress analyses of advanced hot-gas filters obtained from different manufacturers. These filters were fabricated from both monolithic ceramics and composites. The composite filters, made of both oxide and nonoxide materials, were in both as-fabricated and exposed conditions, whereas the monolithic filters were made only of nonoxide materials. Mechanical property measurement of composite filters included diametral compression testing with O-ring specimens and burst-testing of short filter segments with rubber plugs. In-situ strength of fibers in the composite filters was evaluated by microscopic technique. Thermal shock/fatigue resistance was estimated by measuring the strengths of filter specimens before and after thermal cycling from an air environment at elevated temperatures to a room temperature oil bath. Filter performance during mechanical and thermal shock/fatigue loadings was correlated with microstructural observations. Micromechanical models were developed to derive properties of composite filter constituents on the basis of measured mechanical properties of the filters. Subsequently, these properties were used to analytically predict the performance of composite filters during thermal shock loading.

  16. Advanced Measurements of Silicon Carbide Ceramic Matrix Composites

    SciTech Connect

    Farhad Farzbod; Stephen J. Reese; Zilong Hua; Marat Khafizov; David H. Hurley

    2012-08-01

    Silicon carbide (SiC) is being considered as a fuel cladding material for accident tolerant fuel under the Light Water Reactor Sustainability (LWRS) Program sponsored by the Nuclear Energy Division of the Department of Energy. Silicon carbide has many potential advantages over traditional zirconium based cladding systems. These include high melting point, low susceptibility to corrosion, and low degradation of mechanical properties under neutron irradiation. In addition, ceramic matrix composites (CMCs) made from SiC have high mechanical toughness enabling these materials to withstand thermal and mechanical shock loading. However, many of the fundamental mechanical and thermal properties of SiC CMCs depend strongly on the fabrication process. As a result, extrapolating current materials science databases for these materials to nuclear applications is not possible. The “Advanced Measurements” work package under the LWRS fuels pathway is tasked with the development of measurement techniques that can characterize fundamental thermal and mechanical properties of SiC CMCs. An emphasis is being placed on development of characterization tools that can used for examination of fresh as well as irradiated samples. The work discuss in this report can be divided into two broad categories. The first involves the development of laser ultrasonic techniques to measure the elastic and yield properties and the second involves the development of laser-based techniques to measurement thermal transport properties. Emphasis has been placed on understanding the anisotropic and heterogeneous nature of SiC CMCs in regards to thermal and mechanical properties. The material properties characterized within this work package will be used as validation of advanced materials physics models of SiC CMCs developed under the LWRS fuels pathway. In addition, it is envisioned that similar measurement techniques can be used to provide process control and quality assurance as well as measurement of

  17. Creep Life Prediction of Ceramic Components Using the Finite Element Based Integrated Design Program (CARES/Creep)

    NASA Technical Reports Server (NTRS)

    Jadaan, Osama M.; Powers, Lynn M.; Gyekenyesi, John P.

    1997-01-01

    The desirable properties of ceramics at high temperatures have generated interest in their use for structural applications such as in advanced turbine systems. Design lives for such systems can exceed 10,000 hours. Such long life requirements necessitate subjecting the components to relatively low stresses. The combination of high temperatures and low stresses typically places failure for monolithic ceramics in the creep regime. The objective of this work is to present a design methodology for predicting the lifetimes of structural components subjected to multiaxial creep loading. This methodology utilizes commercially available finite element packages and takes into account the time varying creep stress distributions (stress relaxation). In this methodology, the creep life of a component is divided into short time steps, during which, the stress and strain distributions are assumed constant. The damage, D, is calculated for each time step based on a modified Monkman-Grant creep rupture criterion. For components subjected to predominantly tensile loading, failure is assumed to occur when the normalized accumulated damage at any point in the component is greater than or equal to unity.

  18. Full-field characterization of thermal diffusivity in continuous-fiber ceramic composite materials and components

    NASA Astrophysics Data System (ADS)

    Steckenrider, J. Scott; Ellingson, William A.; Rothermel, Scott A.

    1995-03-01

    Continuous-fiber ceramic matrix composites (CFCCs) are currently being developed for various high-temperature applications, including use in advanced heat engines. Among the material classes of interest for such applications are silicon carbide (SiC)-fiber-reinforced SiC (SiC(f)/SiC), SiC-fiber-reinforced silicon nitride (SiC(f)/Si3N4), aluminum oxide (Al2O3)-fiber-reinforced Al2O3 (Al2O3(f)/Al2O3), and others. In such composites, the condition of the interfaces (between the fibers and matrix) are critical to the mechanical and thermal behavior of the component (as are conventional mechanical defects such as cracks, porosity, etc.). For example, oxidation of this interface (especially on carbon coated fibers) can seriously degrade both mechanical and thermal properties. Furthermore, thermal shock damage can degrade the matrix through extensive crack generation. A nondestructive evaluation method that could be used to assess interface condition, thermal shock damage, and to detect other `defects' would thus be very beneficial, especially if applicable to full-scale components. One method under development uses infrared thermal imaging to provide `single-shot' full-field assessment of the distribution of thermal properties in large components by measuring thermal diffusivity. By applying digital image filtering, interpolation, and least-squares-estimation techniques for noise reduction, we can achieve acquisition and analysis times of minutes or less with submillimeter spatial resolution. The system developed at Argonne National Laboratory has been used to examine the effects of thermal shock, oxidation treatment, density variations, and variations in oxidation resistance coatings in a full array of test specimens. Subscale CFCC components with nonplanar geometries have also been studied for manufacturing-induced variations in thermal properties.

  19. Development of metrological NDE methods for microturbine ceramic components

    SciTech Connect

    Lee, H.-R.; Ellingson, W. A.

    1999-12-23

    In this work, X-ray computed tomographic imaging technology with high spatial resolution has been explored for metrological applications to Si{sub 3}N{sub 4} ceramic turbine wheels. X-ray computed tomography (XCT) data were acquired by a charge-coupled device detector coupled to an image intensifier. Cone-beam XCT reconstruction algorithms were used to allow full-volume data acquisition from the turbine wheels. Special software was developed so that edge detection and complex blade contours could be determined from the XCT data. The feasibility of using the XCT for dimensional analyses was compared with that of a coordinate-measuring machine. Details of the XCT system, data acquisition, and dimensional comparisons will be presented.

  20. Advanced Ceramic Technology for Space Applications at NASA MSFC

    NASA Technical Reports Server (NTRS)

    Alim, Mohammad A.

    2003-01-01

    The ceramic processing technology using conventional methods is applied to the making of the state-of-the-art ceramics known as smart ceramics or intelligent ceramics or electroceramics. The sol-gel and wet chemical processing routes are excluded in this investigation considering economic aspect and proportionate benefit of the resulting product. The use of ceramic ingredients in making coatings or devices employing vacuum coating unit is also excluded in this investigation. Based on the present information it is anticipated that the conventional processing methods provide identical performing ceramics when compared to that processed by the chemical routes. This is possible when sintering temperature, heating and cooling ramps, peak temperature (sintering temperature), soak-time (hold-time), etc. are considered as variable parameters. In addition, optional calcination step prior to the sintering operation remains as a vital variable parameter. These variable parameters constitute a sintering profile to obtain a sintered product. Also it is possible to obtain identical products for more than one sintering profile attributing to the calcination step in conjunction with the variables of the sintering profile. Overall, the state-of-the-art ceramic technology is evaluated for potential thermal and electrical insulation coatings, microelectronics and integrated circuits, discrete and integrated devices, etc. applications in the space program.

  1. Process development for electron beam joining of ceramic and glass components

    SciTech Connect

    Turman, B.N.; Glass, S.J.; Yang, P.; Gerstle, F.P.; Halbleib, J.A.; Voth, T.E.; McKenzie, B.; Clifford, J.R.; Habiger, K.

    1997-11-01

    The purpose of this project is to develop and extend the electron beam joining process to applications related to Mo/Al{sub 2}O{sub 3} cermets for neutron tube fabrication, glass seals for flat panel displays, and ceramics for structural applications. The key issue is the identification of the allowable operating ranges that produce thermal conditions favorable to robust joining and sealing. High strength, hermetic braze joints between ceramic components have been produced using high energy electron beams. With a penetration depth into a typical ceramic of {approximately} 1 cm for a 10 MeV electron beam, this method provides the capability for rapid, transient brazing operations where temperature control of heat sensitive components is essential. The method deposits energy directly into a buried joint, allowing otherwise inaccessible interfaces to be brazed. The combination of transient heating, with higher thermal conductivity, lower heat capacity, and lower melting temperature of braze metals relative to the ceramic materials, enables a pulsed high power beam to melt a braze metal without producing excessive ceramic temperatures. The authors have demonstrated the feasibility of this process related to ceramic coupons a well as ceramic and glass tubes and cylindrical shapes. The transient thermal response was predicted, using as input the energy absorption predicted from the coupled electron-photon and thermal transport analysis. The joining experiments were conducted with an RF linear accelerator at 10--13 MV. Joining experiments have provided high strength joints between alumina and alumina and between alumina and cermet joints in cylindrical geometry. These joints provided good hermetic seals.

  2. Advanced Integrated Optical Signal Processing Components.

    NASA Astrophysics Data System (ADS)

    Rastani, Kasra

    This research was aimed at the development of advanced integrated optical components suitable for devices capable of processing multi-dimensional inputs. In such processors, densely packed waveguide arrays with low crosstalk are needed to provide dissection of the information that has been partially processed. Waveguide arrays also expand the information in the plane of the processor while maintaining its coherence. Rib waveguide arrays with low loss, high mode confinement and highly uniform surface quality (660 elements, 8 μm wide, 1 μm high, and 1 cm long with 2 mu m separations) were fabricated on LiNbO _3 substrates through the ion beam milling technique. A novel feature of the multi-dimensional IO processor architecture proposed herein is the implementation of large area uniform outcoupling (with low to moderate outcoupling efficiencies) from rib waveguide arrays in order to access the third dimension of the processor structure. As a means of outcoupling, uniform surface gratings (2 μm and 4 μm grating periods, 0.05 μm high and 1 mm long) with low outcoupling efficiencies (of approximately 2-18%/mm) were fabricated on the nonuniform surface of the rib waveguide arrays. As a practical technique of modulating the low outcoupling efficiencies of the surface gratings, it was proposed to alter the period of the grating as a function of position along each waveguide. Large aperture (2.5 mm) integrated lenses with short positive focal lengths (1.2-2.5 cm) were developed through a modification of the titanium-indiffused proton exchanged (TIPE) technique. Such integrated lenses were fabricated by increasing the refractive index of the slab waveguides by the TIPE process while maintaining the refractive index of the lenses at the lower level of Ti:LiNbO _3 waveguide. By means of curvature reversal of the integrated lenses, positive focal length lenses have been fabricated while providing high mode confinement for the slab waveguide. The above elements performed as

  3. Advanced Ceramic Matrix Composites with Multifunctional and Hybrid Structures

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Morscher, Gregory N.

    2004-01-01

    Ceramic matrix composites are leading candidate materials for a number of applications in aeronautics, space, energy, and nuclear industries. Potential composite applications differ in their requirements for thickness. For example, many space applications such as "nozzle ramps" or "heat exchangers" require very thin (< 1 mm) structures whereas turbine blades would require very thick parts (> or = 1 cm). Little is known about the effect of thickness on stress-strain behavior or the elevated temperature tensile properties controlled by oxidation diffusion. In this study, composites consisting of woven Hi-Nicalon (trademark) fibers a carbon interphase and CVI SiC matrix were fabricated with different numbers of plies and thicknesses. The effect of thickness on matrix crack formation, matrix crack growth and diffusion kinetics will be discussed. In another approach, hybrid fiber-lay up concepts have been utilized to "alloy" desirable properties of different fiber types for mechanical properties, thermal stress management, and oxidation resistance. Such an approach has potential for the C(sub I)-SiC and SiC(sub f)-SiC composite systems. CVI SiC matrix composites with different stacking sequences of woven C fiber (T300) layers and woven SiC fiber (Hi-Nicalon (trademark)) layers were fabricated. The results will be compared to standard C fiber reinforced CVI SiC matrix and Hi-Nicalon reinforced CVI SiC matrix composites. In addition, shear properties of these composites at different temperatures will also be presented. Other design and implementation issues will be discussed along with advantages and benefits of using these materials for various components in high temperature applications.

  4. Advanced Ceramics for Use as Fuel Element Materials in Nuclear Thermal Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Valentine, Peter G.; Allen, Lee R.; Shapiro, Alan P.

    2012-01-01

    With the recent start (October 2011) of the joint National Aeronautics and Space Administration (NASA) and Department of Energy (DOE) Advanced Exploration Systems (AES) Nuclear Cryogenic Propulsion Stage (NCPS) Program, there is renewed interest in developing advanced ceramics for use as fuel element materials in nuclear thermal propulsion (NTP) systems. Three classes of fuel element materials are being considered under the NCPS Program: (a) graphite composites - consisting of coated graphite elements containing uranium carbide (or mixed carbide), (b) cermets (ceramic/metallic composites) - consisting of refractory metal elements containing uranium oxide, and (c) advanced carbides consisting of ceramic elements fabricated from uranium carbide and one or more refractory metal carbides [1]. The current development effort aims to advance the technology originally developed and demonstrated under Project Rover (1955-1973) for the NERVA (Nuclear Engine for Rocket Vehicle Application) [2].

  5. Thermal Conductivity of Advanced Ceramic Thermal Barrier Coatings Determined by a Steady-state Laser Heat-flux Approach

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Miller, Robert A.

    2004-01-01

    The development of low conductivity and high temperature capable thermal barrier coatings requires advanced testing techniques that can accurately and effectively evaluate coating thermal conductivity under future high-performance and low-emission engine heat-flux conditions. In this paper, a unique steady-state CO2 laser (wavelength 10.6 microns) heat-flux approach is described for determining the thermal conductivity and conductivity deduced cyclic durability of ceramic thermal and environmental barrier coating systems at very high temperatures (up to 1700 C) under large thermal gradients. The thermal conductivity behavior of advanced thermal and environmental barrier coatings for metallic and Si-based ceramic matrix composite (CMC) component applications has also been investigated using the laser conductivity approach. The relationships between the lattice and radiation conductivities as a function of heat flux and thermal gradient at high temperatures have been examined for the ceramic coating systems. The steady-state laser heat-flux conductivity approach has been demonstrated as a viable means for the development and life prediction of advanced thermal barrier coatings for future turbine engine applications.

  6. Current status and future aspects of R&D activities on electro- ceramic components in Japanese industry

    NASA Astrophysics Data System (ADS)

    Takagi, Hiroshi

    2011-05-01

    The oldest pottery in Japan was made 16,500 years ago in Jomon period. On the background of a long history of Japanese ceramics, Murata and other Japanese manufacturers have been developing electro-ceramic materials and manufacturing many kinds of electronic components using them. In 1937, TDK manufactured ferrite cores first in the world. Then, Japanese electro-ceramic industry has led the world on electro-ceramic materials and components until now, especially in the fields of BaTiO3, PZT, PTC thermistor, ZnO varistor and insulating ceramics. From the analysis of the papers reported lately, R&D activities of Japanese manufacturers are understood to cover not only improving properties of electro-ceramics, but also appropriate technologies and basic technologies.

  7. Development of Cost-Effective Low-Permeability Ceramic and Refractory Components for Aluminum Melting and Casting

    SciTech Connect

    Kadolkar, Puja; Ott, Ronald D

    2006-02-01

    A recent review by the U.S. Advanced Ceramics Association, the Aluminum Association, and the U.S. Department of Energy's Office of Industrial Technologies (DOE/OIT) described the status of advanced ceramics for aluminum processing, including monolithics, composites, and coatings. The report observed that monolithic ceramics (particularly oxides) have attractive properties such as resistance to heat, corrosion, thermal shock, abrasion, and erosion [1]. However, even after the developments of the past 25 years, there are two key barriers to commercialization: reliability and cost-effectiveness. Industry research is therefore focused on eliminating these barriers. Ceramic coatings have likewise undergone significant development and a variety of processes have been demonstrated for applying coatings to substrates. Some processes, such as thermal barrier coatings for gas turbine engines, exhibit sufficient reliability and service life for routine commercial use. Worldwide, aluminum melting and molten metal handling consumes about 506,000 tons of refractory materials annually. Refractory compositions for handling molten aluminum are generally based on dense fused cast silica or mullite. The microstructural texture is extremely important because an interlocking mass of coarser grains must be bonded together by smaller grains in order to achieve adequate strength. At the same time, well-distributed microscopic pores and cracks are needed to deflect cracks and prevent spalling and thermal shock damage [2]. The focus of this project was to develop and validate new classes of cost-effective, low-permeability ceramic and refractory components for handling molten aluminum in both smelting and casting environments. The primary goal was to develop improved coatings and functionally graded materials that will possess superior combinations of properties, including resistance to thermal shock, erosion, corrosion, and wetting. When these materials are successfully deployed in

  8. Recent Advances in Materials for All-Ceramic Restorations

    PubMed Central

    Griggs, Jason A.

    2010-01-01

    SYNOPSIS The past three years of research on materials for all-ceramic veneers, inlays, onlays, single-unit crowns, and multi-unit restorations are reviewed. The primary changes in the field were the proliferation of zirconia-based frameworks and computer-aided fabrication of prostheses, as well as, a trend toward more clinically relevant in vitro test methods. This report includes an overview of ceramic fabrication methods, suggestions for critical assessment of material property data, and a summary of clinical longevity for prostheses constructed of various materials. PMID:17586152

  9. Advanced ceramic material for high temperature turbine tip seals

    NASA Technical Reports Server (NTRS)

    Vogan, J. W.; Solomon, N. G.; Stetson, A. R.

    1980-01-01

    Forty-one material systems were evaluated for potential use in turbine blade tip seal applications at 1370 C. Both ceramic blade tip inserts and abradable ceramic tip shoes were tested. Hot gas erosion, impact resistance, thermal stability, and dynamic rub performance were the criteria used in rating the various materials. Silicon carbide and silicon nitride were used, both as blade tips and abradables. The blade tip inserts were fabricated by hot pressing while low density and honeycomb abradables were sintered or reaction bonded.

  10. Recent advances in materials for all-ceramic restorations.

    PubMed

    Griggs, Jason A

    2007-07-01

    The past 3 years of research on materials for all-ceramic veneers, inlays, onlays, single-unit crowns, and multi-unit restorations are reviewed in this article. The primary changes in the field were the proliferation of zirconia-based frameworks and computer-aided fabrication of prostheses, and a trend toward more clinically relevant in vitro test methods. This article includes an overview of ceramic fabrication methods, suggestions for critical assessment of material property data, and a summary of clinical longevity for prostheses constructed of various materials.

  11. Challenges and Opportunities in Reactive Processing and Applications of Advanced Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay

    2003-01-01

    Recently, there has been a great deal of interest in the research, development, and commercialization of innovative synthesis and processing technologies for advanced ceramics and composite materials. Reactive processing approaches have been actively considered due to their robustness, flexibility, and affordability. A wide variety of silicon carbide-based advanced ceramics and composites are currently being fabricated using the processing approaches involving reactive infiltration of liquid and gaseous species into engineered fibrous or microporous carbon performs. The microporous carbon performs have been fabricated using the temperature induced phase separation and pyrolysis of two phase organic (resin-pore former) mixtures and fiber reinforcement of carbon and ceramic particulate bodies. In addition, pyrolyzed native plant cellulose tissues also provide unique carbon templates for manufacturing of non-oxide and oxide ceramics. In spite of great interest in this technology due to their affordability and robustness, there is a lack of scientific basis for process understanding and many technical challenges still remain. The influence of perform properties and other parameters on the resulting microstructure and properties of final material is not well understood. In this presentation, mechanism of silicon-carbon reaction in various systems and the effect of perform microstructure on the mechanical properties of advanced silicon carbide based materials will be discussed. Various examples of applications of reactively processed advanced silicon carbide ceramics and composite materials will be presented.

  12. International Standards for Properties and Performance of Advanced Ceramics - 30 years of Excellence

    NASA Technical Reports Server (NTRS)

    Jenkins, Michael G.; Salem, Jonathan A.; Helfinstine, John; Quinn, George D.; Gonczy, Stephen T.

    2016-01-01

    Mechanical and physical properties/performance of brittle bodies (e.g., advanced ceramics and glasses) can be difficult to measure correctly unless the proper techniques are used. For three decades, ASTM Committee C28 on Advanced Ceramics, has developed numerous full-consensus standards (e.g., test methods, practices, guides, terminology) to measure various properties and performance of a monolithic and composite ceramics and coatings that, in some cases, may be applicable to glasses. These standards give the "what, how, how not, why, why not, etc." for many mechanical, physical, thermal, properties and performance of advanced ceramics. Use of these standards provides accurate, reliable, repeatable and complete data. Involvement in ASTM Committee C28 has included users, producers, researchers, designers, academicians, etc. who write, continually update, and validate through round robin test programmes, more than 45 standards in the 30 years since the Committee's inception in 1986. Included in this poster is a pictogram of the ASTM Committee C28 standards and how to obtain them either as i) individual copies with full details or ii) a complete collection in one volume. A listing of other ASTM committees of interest is included. In addition, some examples of the tangible benefits of standards for advanced ceramics are employed to demonstrate their practical application.

  13. Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components

    NASA Technical Reports Server (NTRS)

    Sun, J. G.; Verrilli, M. J.; Stephan, R.; Barnett, T. R.; Ojard, G.

    2003-01-01

    Combustor liners fabricated from a SiC/SiC composite were nondestructively interrogated before and after combustion rig testing by X-ray, ultrasonic and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications were found to correlate with reduced material properties obtained after rig testing. The thermography indications in the SiC/SiC liners were delaminations and damaged fiber tows, as determined through microstructural examinations. [copyright] 2003 American Institute of Physics

  14. Nondestructive evaluation of ceramic matrix composite combustor components.

    SciTech Connect

    Sun, J. G.; Verrilli, M. J.; Stephan, R.; Barnett, T. R.; Ojard, G.

    2002-11-08

    Combustor liners fabricated from a SiC/SiC composite were nondestructively interrogated before and after combustion rig testing. The combustor liners were inspected by X-ray, ultrasonic and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications were found to correlate with reduced material properties obtained after rig testing. Microstructural examination of the SiC/SiC liners revealed the thermography indications to be delaminations and damaged fiber tows.

  15. Slow Crack Growth and Fatigue Life Prediction of Ceramic Components Subjected to Variable Load History

    NASA Technical Reports Server (NTRS)

    Jadaan, Osama

    2001-01-01

    Present capabilities of the NASA CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code include probabilistic life prediction of ceramic components subjected to fast fracture, slow crack growth (stress corrosion), and cyclic fatigue failure modes. Currently, this code has the capability to compute the time-dependent reliability of ceramic structures subjected to simple time-dependent loading. For example, in slow crack growth (SCG) type failure conditions CARES/Life can handle the cases of sustained and linearly increasing time-dependent loads, while for cyclic fatigue applications various types of repetitive constant amplitude loads can be accounted for. In real applications applied loads are rarely that simple, but rather vary with time in more complex ways such as, for example, engine start up, shut down, and dynamic and vibrational loads. In addition, when a given component is subjected to transient environmental and or thermal conditions, the material properties also vary with time. The objective of this paper is to demonstrate a methodology capable of predicting the time-dependent reliability of components subjected to transient thermomechanical loads that takes into account the change in material response with time. In this paper, the dominant delayed failure mechanism is assumed to be SCG. This capability has been added to the NASA CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code, which has also been modified to have the ability of interfacing with commercially available FEA codes executed for transient load histories. An example involving a ceramic exhaust valve subjected to combustion cycle loads is presented to demonstrate the viability of this methodology and the CARES/Life program.

  16. Development of wear resistant ceramic coatings for diesel engine components

    SciTech Connect

    Haselkorn, M.H. )

    1992-04-01

    Improved fuel economy and a reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, insulating the combustion chamber components will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150{degree}C to over 300{degree}C. Existing ring/liner materials can not withstand these higher operating temperatures and for this reason, new materials need to be developed for this critical tribological interface. The overall goal of this program is the development of piston ring/cylinder liner material pairs which would be able to provide the required friction and wear properties at these more severe operating conditions. More specifically, this program first selected, and then evaluated, potential d/wear resistant coatings which could be applied to either piston rings an or cylinder liners and provide, at 350{degree}C under lubricated conditions, coefficients of friction below 0.1 and wear rates of less than 25 {times} lO{sup {minus}6} mm/hour. The processes selected for applying the candidate wear resistant coatings to piston rings and/or cylinder liners were plasma spraying, chemical vapor, physical vapor and low temperature arc vapor deposition techniques as well as enameling techniques.

  17. Metal hypersensitivity in total knee arthroplasty: revision surgery using a ceramic femoral component - a case report.

    PubMed

    Bergschmidt, Philipp; Bader, Rainer; Mittelmeier, Wolfram

    2012-03-01

    We present a case involving the revision of a total knee arthroplasty with a metal femoral component using a ceramic implant due to metal hypersensitivity. A 58-year-old female patient underwent total knee arthroplasty (TKA) with a standard metal bicondylar knee system. She suffered from persistent pain and strong limitations in her range of motion (ROM) associated with flexion during the early postoperative period. Arthroscopic arthrolysis of the knee joint and intensive active and passive physical treatment, in combination with a cortisone regime, temporarily increased the ROM and reduced pain. No signs of low grade infection or other causes of implant failure were evident. Histology of synovial tissue revealed lymphoplasmacellular fibrinous tissue, consistent with a type IV allergic reaction. Allergometry (skin reaction) revealed type IV hypersensitivity against nickel-II-sulfate and palladium chloride. Revision surgery of the metal components was performed with a cemented ceramic femoral component (same bicondylar design) and a cemented titanium alloy tibial component. Postoperative evaluations were performed 10days, and 3 and 12months after the revision surgery. There was an increased ROM in flexion to 90° at the 12month follow-up. No swelling or effusion was observed at all clinical examinations after the revision surgery. No pain at rest and moderate walking pain were evident. The presented case demonstrates that ceramic implants are a promising solution for patients suffering from hypersensitivity to metal ions in total knee arthroplasty.

  18. Extremely high fracture rate of a modular acetabular component with a sandwich polyethylene ceramic insertion for THA: a preliminary report.

    PubMed

    Kircher, Jörn; Bader, Rainer; Schroeder, Bettina; Mittelmeier, Wolfram

    2009-09-01

    Improvements of ceramic components and design changes have reduced failure rates over the past 30 years in total hip arthroplasty. We present a series of n = 11 cases with ceramic failure out of n = 113 implantations, from which n = 66 were ceramic-on-ceramic (n = 50 with ceramic insert with sandwich in polyethylene and n = 16 with directly fixed ceramic inlay) and n = 47 ceramic on polyethylene bearings, between 1999 and 2001 after introduction of a new implantation system to the market. The overall fracture rate of ceramic for the whole series (n = 113) was 9.7%. For the combination ceramic head with UHMW-PE (n = 47) the fracture rate was 2.1%. For the combination ceramic with ceramic (n = 66) the fracture rate was 15.2%. For the combination ceramic with ceramic sandwich in PE (n = 50) the failure rate was 18%. Only three patients experienced a trauma. Demography of patients (age, gender, body weight and BMI) was not statistically different between patients with failed ceramics and the rest of the patients making patient-specific risk factors unlikely to be an explanation for the failures. Retrospective X-ray analysis of the cup positioning did not show significant difference between failed and non-failed implants in terms of mean cup inclination and version making also operation-specific factors unlikely to be the only reason of this high failure rate. Therefore, manufacturer-specific factors such as design features may have contributed to this high failure rate. Further analysis of the whole series with biomechanical testing of the retrieved material needs to be performed.

  19. Advanced Materials and Cell Components for NASA's Exploration Missions

    NASA Technical Reports Server (NTRS)

    Reid, Concha M.

    2009-01-01

    This is an introductory paper for the focused session "Advanced Materials and Cell Components for NASA's Exploration Missions". This session will concentrate on electrochemical advances in materials and components that have been achieved through efforts sponsored under NASA's Exploration Systems Mission Directorate (ESMD). This paper will discuss the performance goals for components and for High Energy and Ultra High Energy cells, advanced lithium-ion cells that will offer a combination of higher specific energy and improved safety over state-of-the-art. Papers in this session will span a broad range of materials and components that are under development to enable these cell development efforts.

  20. Advanced laser microfabrication of photonic components

    NASA Astrophysics Data System (ADS)

    Herman, Peter R.; Chen, Kevin P.; Corkum, Paul B.; Naumov, Andrei; Ng, Sandy; Zhang, Jie

    2000-11-01

    The powerful transition from electronic to photonic systems in today's Internet-driven communication industry is driving the development of processes to miniaturize and integrate optical components. New processing and packaging technologies are now required that can precisely shape and assemble transparent optical components to sub-wavelength accuracy. Laser microfabrication technology is beginning to play a role here. Our groups are exploring two extremes in laser technology- ultrafast lasers and very short wavelength F2 lasers- to microstructure optical surfaces and to profile refractive-index structures inside transparent glasses. In this paper, we compare photosensitivity responses, spatial resolution, and processing windows for the deep-ultraviolet and ultrafast laser approaches, and discuss prospects for laser printing and trimming of optical waveguide components and circuits.

  1. Advanced NDE Technologies for Powder Metal Components

    SciTech Connect

    Martin, P; Haskins, J; Thomas, G; Dolan, K

    2003-05-01

    Nondestructive evaluation encompasses numerous technologies that assess materials and determine important properties. This paper demonstrates the applicability of several of these technologies to the field of powder metallurgy. The usual application of nondestructive evaluation is to detect and quantify defects in fully sintered product. But probably its most appealing role is to sense problems earlier in the manufacturing process to avoid making defects at all. Also nondestructive evaluation can be incorporated into the manufacturing processes to monitor important parameters and control the processes to produce defect free product. Nondestructive evaluation can characterize powders, evaluate components in the green state, monitor the sintering process, and inspect the final component.

  2. Flexure Strength of Advanced Ceramics - A Round Robin Exercise

    DTIC Science & Technology

    1989-07-01

    tests. McMahon showed a very strong effect at room temperature on a high alumina ceramic. 4 Most of the laboratories in the present exer- cise did...Materials, and was concluded in 1987. Flexural strength at room temperature was measured for a sintercd alumina and a reaction-bonded silicon nitride... sintered alumina and reaction-bonded silicon nitride were quite satisfactory for the exercise. Flexure strengths measured by seven laboratories using

  3. Investigation of the Kinetic Energy Characterization of Advanced Ceramics

    DTIC Science & Technology

    2015-04-01

    of Science, under a US Army International Technology Center contract. These ceramic formulations were compared with standard armor- grade boron...a sensitivity equivalent to that of other ballistic test methods. The change in penetration into the metal plates provides a comparison with which...thick. An epoxy resin, Dureflex Optical Aliphatic Polyether Polyurethane Grade A4700, was used to attach each tile to the first 50.8-mm (2-inch

  4. Recent advances in aluminum oxynitride (ALON) optical ceramic

    NASA Astrophysics Data System (ADS)

    Goldman, Lee M.; Hartnett, Thomas M.; Wahl, Joseph M.; Ondercin, Robert J.; Olson, Karen R.

    2001-09-01

    Aluminum Oxynitride or ALON optical ceramic is transparent material, developed and patented by Raytheon, which is very similar to sapphire, being comprised mostly of Al2O3 with a small amount of additional nitrogen. This nitrogen addition has the effect of producing a cubic material whose optical and mechanical properties are isotropic. Importantly, this means that it can be produced by powder processing methods, which are scalable to larger sizes, and at lower prices than can be achieved by the single crystal growth techniques that are used to grow sapphire. Furthermore, its isotropic properties make it much easier to grind and polish than sapphire. Recently, the interest in ALON optical ceramic has grown substantially following impressive results in ballistic testing. Ballistic laminates, containing ALON layers, have demonstrated protection against armor piercing rounds, at half the areal density and thickness of conventional ballistic laminates. ALON plates as large as 14x20in are being produced, under Air Force funding, for evaluation as IR windows and transparent armor, using conventional powder processing techniques. The production processes themselves are now being scaled to produce large pieces and large quantities of ALON optical ceramic.

  5. Recent advances in the field of ceramic fibers and ceramic matrix composites

    NASA Astrophysics Data System (ADS)

    Naslain, R.

    2005-03-01

    Progress achieved during the last decade in the field of ceramic fibers and related ceramic matrix composites is reviewed. Both SiC-based and alumina-based fine fibers have been improved in terms of thermal stability and creep resistance with temperature limit of about 1400 and 1200 ° C, respectively. Two concepts for achieving damage-tolerant ceramic matrix composites have been identified : (i) that of non-oxide composites with a dense matrix in which matrix cracks formed under load are deflected and arrested in a weak fiber coating referred to as the interphase and (ii) that of all-oxide composites with a highly porous matrix with no need of any fiber coating. The lifetime under load of non-oxide composites in oxidizing atmospheres, is improved through the use of multilayered self-healing interphases and matrices deposited from gaseous precursors by chemical vapor infiltration (CVI). Lifetime ranging from 1000 to 10,000 hours at 1200 ° C under cyclic loading in air are foreseen. Alumina-based composites although attractive for long term exposures in oxidizing atmospheres up to ≈1200 ° C, are still experimental materials.

  6. Failure analysis of sandwich-type ceramic-on-ceramic hip joints: A spectroscopic investigation into the role of the polyethylene shell component.

    PubMed

    Okita, Shinya; Hasegawa, Masahiro; Takahashi, Yasuhito; Puppulin, Leonardo; Sudo, Akihiro; Pezzotti, Giuseppe

    2014-03-01

    The mechanisms leading to systematic failure in modular acetabular components with a sandwich insertion (alumina/polyethylene/titanium) have been reconsidered in light of the newly collected Raman spectroscopic results. Raman assessments were conducted on the polyethylene shells, which belonged to a series of six failed sandwich implants with in vivo lifetimes ranging between 2 and 9yr. With only one exception, all implants commonly showed dislodgment of the polyethylene shell during radiographic analyses prior to revision surgery. The polyethylene shell slipped out of the backing titanium shell, while always remaining integer to the ceramic liner. Four implants fractured at the ceramic liners, but their fractures occurred according to distinctly different patterns, which could be rationalized and classified. The insertion of the polyethylene layer, originally conceived to reduce the rigidity of the ceramic-on-ceramic bearing and to prevent impingement between the ceramic liner rim and the femoral neck, played a role in implant failure with its initial (asymmetric) thickness reduction due to creep deformation (eventually followed by cup rotation and backside wear). The results of the present spectroscopic investigation suggest that a simplistic failure classification of the sandwich-type implant as a "ceramic fracture failure" could be misleading and might represent a confounding factor in judging about the reliability of modern ceramic implants.

  7. Advanced aerospace hydraulic systems and components

    NASA Astrophysics Data System (ADS)

    1991-07-01

    The present volume discusses the development of a viable hydraulic circuit breaker, the electromodulated control of supply pressure in hydraulic systems, the flight control actuation system for the B-2 advanced technology bomber, and the B747-400 upper rudder control system with triple tandem valve. Also discussed are a total-flexibility cartridge-valve porting via innovative sealing technology, the A320 pilots' autothrust survey, an all-digital electrohydrostatic servoactuator, and a concurrent design/analysis tool for aircraft hydraulic systems. (For individual items see A93-21841 to A93-21844)

  8. Advanced Rotorcraft Transmission (ART) - Component test results

    NASA Astrophysics Data System (ADS)

    Henry, Z. S.

    1992-07-01

    The preliminary design of the ART and some of the component test results are presented. The goals for the future rotorcraft transmissions include a 25-percent weight reduction in comparison with current state-of-the-art transmissions, a 10-dB reduction in the transmitted noise level, and a system reliability of 5,000 hr mean-time-between-removal for the transmission. The ART tests completed to date support the attainment of the three major goals of the program.

  9. Shock wave loading of high-strength ceramics with components undergoing phase transitions

    NASA Astrophysics Data System (ADS)

    Maevskii, K. K.; Kinelovskii, S. A.

    2016-11-01

    One of the methods of solving the problem of creating ceramics with specified properties is a shock wave loading of multicomponent mixtures. The numerical simulation results of thermodynamic parameters are presented for mixtures consisting of components that experience phase transitions during shock wave loading: quartz SiO2, silicon nitride Si3N4, aluminum nitride AlN. The calculation results obtained by thermodynamic equilibrium component (TEC) models are compared with both the experimental data and the simulation results obtained by other authors.

  10. Innovative grinding wheel design for cost-effective machining of advanced ceramics. Phase I, final report

    SciTech Connect

    Licht, R.H.; Ramanath, S.; Simpson, M.; Lilley, E.

    1996-02-01

    Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics. This program was a cooperative effort involving three Norton groups representing a superabrasive grinding wheel manufacturer, a diamond film manufacturing division and a ceramic research center. The program was divided into two technical tasks, Task 1, Analysis of Required Grinding Wheel Characteristics, and Task 2, Design and Prototype Development. In Task 1 we performed a parallel path approach with Superabrasive metal-bond development and the higher technical risk, CVD diamond wheel development. For the Superabrasive approach, Task 1 included bond wear and strength tests to engineer bond-wear characteristics. This task culminated in a small-wheel screening test plunge grinding sialon disks. In Task 2, an improved Superabrasive metal-bond specification for low-cost machining of ceramics in external cylindrical grinding mode was identified. The experimental wheel successfully ground three types of advanced ceramics without the need for wheel dressing. The spindle power consumed by this wheel during test grinding of NC-520 sialon is as much as to 30% lower compared to a standard resin bonded wheel with 100 diamond concentration. The wheel wear with this improved metal bond was an order of magnitude lower than the resin-bonded wheel, which would significantly reduce ceramic grinding costs through fewer wheel changes for retruing and replacements. Evaluation of ceramic specimens from both Tasks 1 and 2 tests for all three ceramic materials did not show evidence of unusual grinding damage. The novel CVD-diamond-wheel approach was incorporated in this program as part of Task 1. The important factors affecting the grinding performance of diamond wheels made by CVD coating preforms were determined.

  11. Ceramic component reliability with the restructured NASA/CARES computer program

    NASA Technical Reports Server (NTRS)

    Powers, Lynn M.; Starlinger, Alois; Gyekenyesi, John P.

    1992-01-01

    The Ceramics Analysis and Reliability Evaluation of Structures (CARES) integrated design program on statistical fast fracture reliability and monolithic ceramic components is enhanced to include the use of a neutral data base, two-dimensional modeling, and variable problem size. The data base allows for the efficient transfer of element stresses, temperatures, and volumes/areas from the finite element output to the reliability analysis program. Elements are divided to insure a direct correspondence between the subelements and the Gaussian integration points. Two-dimensional modeling is accomplished by assessing the volume flaw reliability with shell elements. To demonstrate the improvements in the algorithm, example problems are selected from a round-robin conducted by WELFEP (WEakest Link failure probability prediction by Finite Element Postprocessors).

  12. Advanced components for spaceborne infrared astronomy

    NASA Technical Reports Server (NTRS)

    Davidson, A. W.

    1984-01-01

    The need for improved cryogenic components to be used in future spaceborne infrared astronomy missions was identified. Improved low noise cryogenic amplifiers operated with infrared detectors, and better cryogenic actuators and motors with extremely low power dissipation are needed. The feasibility of achieving technological breakthroughs in both of these areas was studied. An improved silicon junction field effect transistor (JFET) could be developed if: (1) high purity silicon; (2) optimum dopants; and (3) very high doping levels are used. The feasibility of a simple stepper motor equipped with superconducting coils is demonstrated by construction of such a device based on a standard commercial motor. It is found that useful levels of torque at immeasurably low power levels were achieved. It is concluded that with modest development and optimization efforts, significant performance gains is possible for both cryogenic preamplifiers and superconducting motors and actuators.

  13. Crack Branching and Fracture Mirror Data of Glasses and Advanced Ceramics

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.

    1998-01-01

    The fracture mirror and crack branching constants were determined from three glasses and nine advanced ceramics tested under various loading and specimen configurations in an attempt to use the constants as a data base for fractography. The ratios of fracture mirror or crack branching constant to fracture toughness were found to be approximately two for most ceramic materials tested. A demonstration of how to use the two constants as a tool for verifying stress measurements was presented for silicon nitride disk specimens subjected to high-temperature, constant stress-rate biaxial flexure testing.

  14. Development of a constitutive model for creep and life prediction of advanced silicon nitride ceramics

    SciTech Connect

    Ding, J.L.; Liu, K.C.; Brinkman, C.R.

    1992-12-31

    A constitutive model capable of describing deformation and predicting rupture life was developed for high temperature ceramic materials under general thermal-mechanical loading conditions. The model was developed based on the deformation and fracture behavior observed from a systematic experimental study on an advanced silicon nitride (Si{sub 3}N{sub 4}) ceramic material. Validity of the model was evaluated with reference to creep and creep rupture data obtained under constant and stepwise-varied loading conditions, including the effects of annealing on creep and creep rupture behavior.

  15. Advances in telecom and datacom optical components

    NASA Astrophysics Data System (ADS)

    Eldada, Louay A.

    2001-07-01

    We review and contrast key technologies developed to address the optical components market for telecom and datacom applications. We first look at different material systems, compare their properties, and describe the functions achieved to date in each of them. The material systems reviewed include glass fiber, silica on silicon, silicon on insulator, silicon oxynitride, sol-gels, polymers, thin film dielectrics, lithium niobate, indium phosphide, gallium arsenide, magneto-optic materials, and birefringent crystals. We then look at the most commonly used classes of technology and present their pros and cons as well as the functions achieved to date in each. The technologies reviewed include passive, actuation, and active technologies. The passive technologies described include fused fibers, dispersion-compensating fiber, beam steering (e.g., AWG), Bragg gratings, diffraction gratings, holographic elements, thin film filters, photonic crystals, microrings, and birefringent elements. The actuation technologies include thermo-optics, electro-optics, acousto- optics, magneto-optics, liquid crystals, total internal reflection technologies (e.g., bubble technology), and mechanical actuation (e.g., moving fibers and MEMS). We finally describe active technologies including heterostructures, quantum wells, rare earth doping, and semiconductor optical amplifiers. We also investigate the use of different material systems and technologies to achieve building block functions including lasers, amplifiers, detectors, modulators, polarization controllers, couplers, filters, switches, attenuators, nonreciprocal elements (Faraday rotators or nonreciprocal phase shifters) for isolators and circulators, wavelength converters, and dispersion compensators.

  16. Impact-Resistant Ceramic Coating

    NASA Technical Reports Server (NTRS)

    Wheeler, W. H.; Creedon, J. F.; Izu, Y. D.

    1986-01-01

    Refractory fibers more than double strength of coating. Impact strengths of ceramic coatings increase with increasing whisker content. Silicon carbide whiskers clearly produce largest increase, and improvement grows even more with high-temperature sintering. Coating also improves thermal and mechanical properties of electromagnetic components, mirrors, furnace linings, and ceramic parts of advanced internal-combustion engines.

  17. [The application of inductively coupled plasma atomic emission spectrometry/mass spectrometry to the analysis of advanced ceramic materials].

    PubMed

    Wang, Zheng; Wang, Shi-Wei; Qiu, De-Ren; Yang, Peng-Yuan

    2009-10-01

    Advanced ceramics have been applied to various important fields such as information science, aeronautics and astronautics, and life sciences. However, the optics and electric properties of ceramics are significantly affected by the micro and trace impurities existing in the material even at very low concentration level. Thus, the accurate determination of impurities is important for materials preparation and performance. Methodology of the analysis of advanced ceramic materials using ICP-AES/MS was reviewed in the present paper for the past decade. Various techniques of sample introduction, especially advances in the authors' recent work, are described in detail. The developing trend is also presented. Sixty references are cited.

  18. Ceramic Technology Project

    SciTech Connect

    Not Available

    1992-03-01

    The Ceramic Technology Project was developed by the USDOE Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the USDOE and NASA advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. These programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. A five-year project plan was developed with extensive input from private industry. In July 1990 the original plan was updated through the estimated completion of development in 1993. The objective is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities.

  19. PREFACE: Symposium 1: Advanced Structure Analysis and Characterization of Ceramic Materials

    NASA Astrophysics Data System (ADS)

    Yashima, Masatomo

    2011-05-01

    Preface to Symposium 1 (Advanced Structure Analysis and Characterization of Ceramic Materials) of the International Congress of Ceramics III, held 14-18 November 2010 in Osaka, Japan Remarkable developments have been made recently in the structural analysis and characterization of inorganic crystalline and amorphous materials, such as x-ray, neutron, synchrotron and electron diffraction, x-ray/neutron scattering, IR/Raman scattering, NMR, XAFS, first-principle calculations, computer simulations, Rietveld analysis, the maximum-entropy method, in situ measurements at high temperatures/pressures and electron/nuclear density analysis. These techniques enable scientists to study not only static and long-range periodic structures but also dynamic and short-/intermediate-range structures. Multi-scale characterization from the electron to micrometer levels is becoming increasingly important as a means of understanding phenomena at the interfaces, grain boundaries and surfaces of ceramic materials. This symposium has discussed the structures and structure/property relationships of various ceramic materials (electro, magnetic and optical ceramics; energy and environment related ceramics; bio-ceramics; ceramics for reliability secure society; traditional ceramics) through 38 oral presentations including 8 invited lectures and 49 posters. Best poster awards were given to six excellent poster presentations (Y-C Chen, Tokyo Institute of Technology; C-Y Chung, Tohoku University; T Stawski, University of Twente; Y Hirano, Nagoya Institute of Technology; B Bittova, Charles University Prague; Y Onodera, Kyoto University). I have enjoyed working with my friends in the ICC3 conference. I would like to express special thanks to other organizers: Professor Scott T Misture, Alfred University, USA, Professor Xiaolong Chen, Institute of Physics, CAS, China, Professor Takashi Ida, Nagoya Institute of Technology, Japan, Professor Isao Tanaka, Kyoto University, Japan. I also acknowledge the

  20. New advanced surface modification technique: titanium oxide ceramic surface implants: long-term clinical results

    NASA Astrophysics Data System (ADS)

    Szabo, Gyorgy; Kovacs, Lajos; Barabas, Jozsef; Nemeth, Zsolt; Maironna, Carlo

    2001-11-01

    The purpose of this paper is to discuss the background to advanced surface modification technologies and to present a new technique, involving the formation of a titanium oxide ceramic coating, with relatively long-term results of its clinical utilization. Three general techniques are used to modify surfaces: the addition or removal of material and the change of material already present. Surface properties can also be changed without the addition or removal of material, through the laser or electron beam thermal treatment. The new technique outlined in this paper relates to the production of a corrosion-resistant 2000-2500 A thick, ceramic oxide layer with a coherent crystalline structure on the surface of titanium implants. The layer is grown electrochemically from the bulk of the metal and is modified by heat treatment. Such oxide ceramic-coated implants have a number of advantageous properties relative to implants covered with various other coatings: a higher external hardness, a greater force of adherence between the titanium and the oxide ceramic coating, a virtually perfect insulation between the organism and the metal (no possibility of metal allergy), etc. The coated implants were subjected to various physical, chemical, electronmicroscopic, etc. tests for a qualitative characterization. Finally, these implants (plates, screws for maxillofacial osteosynthesis and dental root implants) were applied in surgical practice for a period of 10 years. Tests and the experience acquired demonstrated the good properties of the titanium oxide ceramic-coated implants.

  1. Development of Thin Film Thermocouples on Ceramic Materials for Advanced Propulsion System Applications

    NASA Technical Reports Server (NTRS)

    Holanda, R.

    1992-01-01

    Thin film thermocouples have been developed for use on metal parts in jet engines to 1000 c. However, advanced propulsion systems are being developed that will use ceramic materials and reach higher temperatures. The purpose of this work is to develop thin film thermocouples for use on ceramic materials. The new thin film thermocouples are Pt13Rh/Pt fabricated by the sputtering process. Lead wires are attached using the parallel-gap welding process. The ceramic materials tested are silicon nitride, silicon carbide, aluminum oxide, and mullite. Both steady state and thermal cycling furnace tests were performed in the temperature range to 1500 C. High-heating-rate tests were performed in an arc lamp heat-flux-calibration facility. The fabrication of the thin film thermocouples is described. The thin film thermocouple output was compared to a reference wire thermocouple. Drift of the thin film thermocouples was determined, and causes of drift are discussed. The results of high heating rate tests up to 2500 C/sec are presented. The stability of the ceramic materials is examined. It is concluded that Pt13Rh/Pt thin film thermocouples are capable of meeting lifetime goals of 50 hours or more up to temperature of 1500 C depending on the stability of the particular ceramic substrate.

  2. Development of thin film thermocouples on ceramic materials for advanced propulsion system applications

    NASA Technical Reports Server (NTRS)

    Holanda, Raymond

    1993-01-01

    Thin film thermocouples were developed for use on metal parts in jet engines to 1000 C. However, advanced propulsion systems are being developed that will use ceramic materials and reach higher temperatures. The purpose is to develop thin film thermocouples for use on ceramic materials. The new thin film thermocouples are Pt13Rh/Pt fabricated by the sputtering process. Lead wires are attached using the parallel-gap welding process. The ceramic materials tested are silicon nitride, silicon carbide, aluminum oxide, and mullite. Both steady state and thermal cycling furnace tests were performed in the temperature range to 1500 C. High-heating-rate tests were performed in an arc lamp heat-flux-calibration facility. The fabrication of the thin film thermocouples is described. The thin film thermocouple output was compared to a reference wire thermocouple. Drift of the thin film thermocouples was determined, and causes of drift are discussed. The results of high heating rate tests up to 2500 C/sec are presented. The stability of the ceramic materials is examined. It is concluded that Pt13Rh/Pt thin film thermocouples are capable of meeting lifetime goals of 50 hr or more up to temperatures of 1500 C depending on the stability of the particular ceramic substrate.

  3. Design of ceramic components with the NASA/CARES computer program

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Manderscheid, Jane M.; Gyekenyesi, John P.

    1990-01-01

    The ceramics analysis and reliability evaluation of structures (CARES) computer program is described. The primary function of the code is to calculate the fast-fracture reliability or failure probability of macro-scopically isotropic ceramic components. These components may be subjected to complex thermomechanical loadings, such as those found in heat engine applications. CARES uses results from MSC/NASTRAN or ANSYS finite-element analysis programs to evaluate how inherent surface and/or volume type flaws component reliability. CARES utilizes the Batdorf model and the two-parameter Weibull cumulative distribution function to describe the effects of multiaxial stress states on material strength. The principle of independent action (PIA) and the Weibull normal stress averaging models are also included. Weibull material strength parameters, the Batdorf crack density coefficient, and other related statistical quantities are estimated from four-point bend bar or uniform uniaxial tensile specimen fracture strength data. Parameter estimation can be performed for a single or multiple failure modes by using a least-squares analysis or a maximum likelihood method. Kolmogorov-Smirnov and Anderson-Darling goodness-to-fit-tests, 90 percent confidence intervals on the Weibull parameters, and Kanofsky-Srinivasan 90 percent confidence band values are also provided. Examples are provided to illustrate the various features of CARES.

  4. Plugging micro-leaks in multi-component, ceramic tubesheets with material leached therefrom

    DOEpatents

    Bieler, B.H.; Tsang, F.Y.

    1985-03-19

    Cracks, in ceramic wall members, on the order of 1 micron or less in width are plugged helium-tight by selectively leaching a component of the wall member with a solvent, letting the resultant leach form a liquid bridge within the crack, removing the solvent and sintering the resultant residue. This method is of particular value for remedying microcracks or channels in a cell member constituting a tubesheet in a hollow fiber type, high temperature battery cell, such as a sodium/sulfur cell, for example. 1 fig.

  5. Plugging micro-leaks in multi-component, ceramic tubesheets with material leached therefrom

    DOEpatents

    Bieler, Barrie H.; Tsang, Floris Y.

    1985-03-19

    Cracks, in ceramic wall members, on the order of 1 micron or less in width are plugged helium-tight by selectively leaching a component of the wall member with a solvent, letting the resultant leach form a liquid bridge within the crack, removing the solvent and sintering the resultant residue. This method is of particular value for remedying microcracks or channels in a cell member constituting a tubesheet in a hollow fiber type, high temperature battery cell, such as a sodium/sulfur cell, for example.

  6. Advanced Nanocrystalline Ceramic Matrix Composites with Improved Toughness

    DTIC Science & Technology

    2009-01-09

    nanocomposites reinforced with niobium and/or carbon nanotubes were fabricated by advanced powder processing techniques and consolidated by spark plasma...tests were conducted on niobium and/or carbon nanotube-reinforced alumina U 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 09-01-2009 13...Toughness Report Title ABSTRACT Alumina-based nanocomposites reinforced with niobium and/or carbon nanotubes were fabricated by advanced powder processing

  7. Development of nondestructive evaluation techniques for high-temperature ceramic heat exchanger components. Tenth quarterly report, January-March 1980

    SciTech Connect

    Kupperman, D.S.; Yuhas, D.; Caines, M.J.

    1980-04-01

    The effectiveness of several conventional and unconventional NDE techniques for specific high-temperature ceramic components was determined. Techniques under study at ANL include dye-enhanced radiography, acoustic microscopy, conventional ultrasonic testing, acoustic-emission detection, acoustic impact testing, holography, interferometry, infrared scanning, internal friction measurements, and overload proof testing. The current effort involves SiC heat-exchanger tubes; previous ceramic NDE efforts at ANL have involved silicon-nitride gas-turbine rotors. Recent results on inspection of SiC heat-exchanger tubing by means of ultrasonic acoustic microscopy techniques and efforts initiated and planned for NDE of ceramic joints are discussed.

  8. Durability and CMAS Resistance of Advanced Environmental Barrier Coatings Systems for SiC/SiC Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming

    2015-01-01

    Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. This paper will emphasize advanced environmental barrier coating developments for SiCSiC turbine airfoil components, by using advanced coating compositions and processing, in conjunction with mechanical and environment testing and durability validations. The coating-CMC degradations and durability in the laboratory simulated engine fatigue-creep and complex operating environments are being addressed. The effects of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the degradation mechanisms of the environmental barrier coating systems will be discussed. The results help understand the advanced EBC-CMC system performance, aiming at the durability improvements of more robust, prime-reliant environmental barrier coatings for successful applications of the component technologies and lifing methodologies.

  9. Effect of ceramic industrial particulate emission control on key components of ambient PM10.

    PubMed

    Minguillón, María Cruz; Monfort, Eliseo; Querol, Xavier; Alastuey, Andrés; Celades, Irina; Miró, José Vicente

    2009-06-01

    The relationship between specific particulate emission control and ambient levels of some PM(10) components (Zn, As, Pb, Cs, Tl) was evaluated. To this end, the industrial area of Castellón (Eastern Spain) was selected, where around 40% of the EU glazed ceramic tiles and a high proportion of EU ceramic frits are produced. The PM(10) emissions from the ceramic processes were calculated over the period 2000-2006, taking into account the degree of implementation of corrective measures throughout the study period. Abatement systems were implemented in the majority of the fusion kilns for frit manufacture in the area as a result of the application of the Directive 1996/61/EC, leading to a marked decrease in PM(10) emissions. By contrast, emissions from tile manufacture remained relatively constant because of the few changes in the implementation of corrective measures. On the other hand, ambient PM(10) levels and composition measurements were carried out from 2002 to 2006. A high correlation between PM(10) emissions from frit manufacture and ambient levels of Zn, As, Pb and Cs (R(2) from 0.61 to 0.98) was observed. On the basis of these results, the potential impact of the implementation of corrective measures to reduce emissions from tile manufacture was quantified, resulting in a possible decrease of 3-5 microg/m(3) and 2 microg/m(3) in ambient mineral PM(10) (on an annual basis) in urban and suburban areas, respectively. This relatively simple methodology allows us to estimate the direct effect of a reduction in primary particulate emissions on ambient levels of key particulate components, and to make a preliminary quantification of the possibilities of air quality improvement by means of further emission reduction. Therefore, it is a useful tool for developing future air quality plans in the study area and in other industrialised areas.

  10. Application of advanced coating techniques to rocket engine components

    NASA Technical Reports Server (NTRS)

    Verma, S. K.

    1988-01-01

    The materials problem in the space shuttle main engine (SSME) is reviewed. Potential coatings and the method of their application for improved life of SSME components are discussed. A number of advanced coatings for turbine blade components and disks are being developed and tested in a multispecimen thermal fatigue fluidized bed facility at IIT Research Institute. This facility is capable of producing severe strains of the degree present in blades and disk components of the SSME. The potential coating systems and current efforts at IITRI being taken for life extension of the SSME components are summarized.

  11. Ferroelectromagnetic solid solutions on the base piezoelectric ceramic materials for components of micromechatronics

    NASA Astrophysics Data System (ADS)

    Bochenek, Dariusz; Zachariasz, Radosław; Niemiec, Przemysław; Ilczuk, Jan; Bartkowska, Joanna; Brzezińska, Dagmara

    2016-10-01

    In the presented work, a ferroelectromagnetic solid solutions based on PZT and ferrite powders have been obtained. The main aim of combination of ferroelectric and magnetic powders was to obtain material showing both electric and magnetic properties. Ferroelectric ceramic powder (in amount of 90%) was based on the doped PZT type solid solution while magnetic component was nickel-zinc ferrite Ni1-xZnxFe2O4 (in amount of 10%). The synthesis of components of ferroelectromagnetic solid solutions was performed using the solid phase sintering. Final densification of synthesized powder has been done using free sintering. The aim of the work was to obtain and examine in the first multicomponent PZT type ceramics admixed with chromium with the following chemical composition Pb0.94Sr0.06(Zr0.46Ti0.54)O3+0.25 at% Cr2O3 and next ferroelectromagnetic solid solution based on a PZT type ferroelectric powder (Pb0.94Sr0.06(Zr0.46Ti0.54)O3+0.25 at% Cr2O3) and nickel-zinc ferrite (Ni0.64Zn0.36Fe2O4), from the point of view of their mechanical and electric properties, such as: electric permittivity, ε; dielectric loss, tanδ; mechanical losses, Q-1; and Young modulus, E.

  12. Processing of Advanced Ceramics Which Have Potential for Use in Gas Turbine Aero Engines

    DTIC Science & Technology

    1989-02-01

    and Materials Laboratory/ G.F. Marsters Laboratofre de structures et materiaux Director/directeur ABSTRACT Si 3N4 and SiC based advanced ceramics that...Alumina, for example, maintains good corrosion resistance , good stiffness, and good strength at high temperatures, but exhibits very poor thermal shock... resistance ; an important property to be considered in the steep temperature gradients and with the rapid -2- temperature fluctuations that are developed

  13. High performance fibers for structurally reliable metal and ceramic composites. [advanced gas turbine engine materials

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.

    1984-01-01

    Very few of the commercially available high performance fibers with low densities, high Young's moduli, and high tensile strengths possess all the necessary property requirements for providing either metal matrix composites (MMC) or ceramic matrix composites (CMC) with high structural reliability. These requirements are discussed in general and examples are presented of how these property guidelines are influencing fiber evaluation and improvement studies at NASA aimed at developing structurally reliable MMC and CMC for advanced gas turbine engines.

  14. Advanced component technologies for energy-efficient turbofan engines

    NASA Technical Reports Server (NTRS)

    Saunders, N. T.

    1980-01-01

    The paper reviews NASA's Energy Efficient Engine Project which was initiated to provide the advanced technology base for a new generation of fuel-conservative engines for introduction into airline service by the late 1980s. Efforts in this project are directed at advancing engine component and systems technologies to a point of demonstrating technology-readiness by 1984. Early results indicate high promise in achieving most of the goals established in the project.

  15. Structural Ceramics Database

    National Institute of Standards and Technology Data Gateway

    SRD 30 NIST Structural Ceramics Database (Web, free access)   The NIST Structural Ceramics Database (WebSCD) provides evaluated materials property data for a wide range of advanced ceramics known variously as structural ceramics, engineering ceramics, and fine ceramics.

  16. Development of nondestructive evaluation techniques for high-temperature ceramic heat exchanger components. Third annual report, October 1979-September 1980

    SciTech Connect

    Kupperman, D S; Yuhas, D; Sciammarella, C; Caines, M J; Winiecki, A

    1980-12-01

    The goals of the present program are not only to develop hardware and procedures for efficiently inspecting ceramic heat-exchanger components in conventional ways, but also to develop advanced NDE techniques that will allow effective failure prediction. The main objectives in FY 1980 have been to (a) develop a computer-interfaced ultrasonic bore-side probe for preservice and in-service inspection, (b) develop and assess techniques for inspection of SiC tubing by acoustic microscopy, and (c) carry out preliminary tests to compare ultrasonic, holographic, and infrared techniques with more conventional dye-penetrant and radiographic methods for inspection of butt joints in ceramic tubes. Circumferential notches, 125 ..mu..m deep x 250 ..mu..m long, on the inner and outer surfaces of sintered and siliconized SiC tubes were successfully detected with an ultrasonic bore-side probe. The acoustic microscope was modified to handle 30- as well as 100-MHz sound waves, since the lower-frequency waves give better penetration of Sic tube walls. The modification decreased the acoustic noise. The ability to detect a notch only 250 x 125 x 75 ..mu..m in size was demonstrated. Efforts to examine a butt joint with dye-penetrant, radiographic, ultrasonic, and holographic-interferometry techniques revealed that while holography seemed to identify more clearly the presence of a crack-like inner surface flaw, ultrasonic pulse-echo and pitch-catch techniques at 22 MHz also indicated the presence of an anomaly; the ultrasonic and holographic results agreed with regard to angular location of the flaw.

  17. Designing Advanced Ceramic Waste Forms for Electrochemical Processing Salt Waste

    SciTech Connect

    Ebert, W. L.; Snyder, C. T.; Frank, Steven; Riley, Brian

    2016-03-01

    This report describes the scientific basis underlying the approach being followed to design and develop “advanced” glass-bonded sodalite ceramic waste form (ACWF) materials that can (1) accommodate higher salt waste loadings than the waste form developed in the 1990s for EBR-II waste salt and (2) provide greater flexibility for immobilizing extreme waste salt compositions. This is accomplished by using a binder glass having a much higher Na2O content than glass compositions used previously to provide enough Na+ to react with all of the Cl– in the waste salt and generate the maximum amount of sodalite. The phase compositions and degradation behaviors of prototype ACWF products that were made using five new binder glass formulations and with 11-14 mass% representative LiCl/KCl-based salt waste were evaluated and compared with results of similar tests run with CWF products made using the original binder glass with 8 mass% of the same salt to demonstrate the approach and select a composition for further studies. About twice the amount of sodalite was generated in all ACWF materials and the microstructures and degradation behaviors confirmed our understanding of the reactions occurring during waste form production and the efficacy of the approach. However, the porosities of the resulting ACWF materials were higher than is desired. These results indicate the capacity of these ACWF waste forms to accommodate LiCl/KCl-based salt wastes becomes limited by porosity due to the low glass-to-sodalite volume ratio. Three of the new binder glass compositions were acceptable and there is no benefit to further increasing the Na content as initially planned. Instead, further studies are needed to develop and evaluate alternative production methods to decrease the porosity, such as by increasing the amount of binder glass in the formulation or by processing waste forms in a hot isostatic press. Increasing the amount of binder glass to eliminate porosity will decrease

  18. Case history advanced coatings for water treatment plant components

    SciTech Connect

    Stephenson, L.D.; Kumar, A.

    2008-12-15

    Components of water treatment plants (WTPs) are susceptible to corrosion from constant immersion in water. A case history of corrosion and proximity to chlorine problems and their treatment at an Army WTP is presented. Solutions included using high micro-silica restoration mortar and advanced coal tar epoxy coatings.

  19. The APS ceramic chambers

    SciTech Connect

    Milton, S.; Warner, D.

    1994-07-01

    Ceramics chambers are used in the Advanced Photon Source (APS) machines at the locations of the pulsed kicker and bumper magnets. The ceramic will be coated internally with a resistive paste. The resistance is chosen to allow the low frequency pulsed magnet field to penetrate but not the high frequency components of the circulating beam. Another design goal was to keep the power density experienced by the resistive coating to a minimum. These ceramics, their associated hardware, the coating process, and our recent experiences with them are described.

  20. Surface engineering glass-metal coatings designed for induction heating of ceramic components

    NASA Astrophysics Data System (ADS)

    Khan, Amir Azam; Labbe, Jean Claude

    2014-06-01

    The term Surface Engineering is of relatively recent origin and use, however, the use of coatings and treatments to render surfaces of materials more suitable for certain application or environment is not new. With the advent of Vacuum Technology, Surface Engineering has gained a whole new impetus, whereby expensive materials with adequate mechanical, chemical and thermal properties are being coated or treated on their surfaces in order to achieve what is called as Surface Engineered materials. The present paper presents an overview of recent achievements in Surface Engineering and gives a detailed view of a specific application where glass-metal composite coatings were deposited on ceramic components in order to render them sensitive to induction heating. Sintered glaze coatings containing silver particles in appropriate concentration can be used for the induction heating of porcelain. Mixtures of glass ceramic powders with silver are used to prepare self-transfer patterns, which are deposited over porcelain. Several configurations of these coatings, which are aesthetic to start with, are employed and heating patterns are recorded. The microstructure of these coatings is discussed in relation to the heating ability by a classical household induction system. The results show that this technique is practical and commercially viable.

  1. High-speed, low-damage grinding of advanced ceramics Phase 1. Final report

    SciTech Connect

    Kovach, J.A.; Malkin, S.

    1995-03-01

    In manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. Most of these costs arise from the conventional multi-step grinding process with numerous grinding wheels and additional capital equipment, perishable dressing tools, and labor. In an attempt to reduce structural ceramic grinding costs, a feasibility investigation was undertaken to develop a single step, roughing-finishing process suitable for producing high-quality silicon nitride ceramic parts at high material removal rates at lower cost than traditional, multi-stage grinding. This feasibility study employed combined use of laboratory grinding tests, mathematical grinding models, and characterization of resultant material surface condition. More specifically, this Phase 1 final report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding and the conditions necessary to achieve the small grain depths of cut necessary for low damage grinding while operating at relatively high material removal rates. Particular issues addressed include determining effects of wheel speed and material removal rate on resulting mode of material removal (ductile or brittle fracture), limiting grinding forces, calculation of approximate grinding zone temperatures developed during HSLD grinding, and developing the experimental systems necessary for determining HSLD grinding energy partition relationships. In addition, practical considerations for production utilization of the HSLD process are also discussed.

  2. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate ('dynamic fatigue') testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rate in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  3. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate (dynamic fatigue) testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rates in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  4. Structural Design of Glass and Ceramic Components for Space System Safety

    NASA Technical Reports Server (NTRS)

    Bernstein, Karen S.

    2007-01-01

    Manned space flight programs will always have windows as part of the structural shell of the crew compartment. Astronauts and cosmonauts need to and enjoy looking out of the spacecraft windows at Earth, at approaching vehicles, at scientific objectives and at the stars. With few exceptions spacecraft windows have been made of glass, and the lessons learned over forty years of manned space flight have resulted in a well-defined approach for using this brittle, unforgiving material in NASA's vehicles, in windows and other structural applications. This chapter will outline the best practices that have developed at NASA for designing, verifying and accepting glass (and ceramic) windows and other components for safe and reliable use in any space system.

  5. Advanced Electrical Materials and Components Development: An Update

    NASA Technical Reports Server (NTRS)

    Schwarze, Gene E.

    2005-01-01

    The primary means to develop advanced electrical components is to develop new and improved materials for magnetic components (transformers, inductors, etc.), capacitors, and semiconductor switches and diodes. This paper will give an update of the Advanced Power Electronics and Components Technology being developed by the NASA Glenn Research Center for use in future Power Management and Distribution subsystems used in space power systems for spacecraft and lunar and planetary surface power. The initial description and status of this technology program was presented two years ago at the First International Energy Conversion Engineering Conference held at Portsmouth, Virginia, August 2003. The present paper will give a brief background of the previous work reported and a summary of research performed the past several years on soft magnetic materials characterization, dielectric materials and capacitor developments, high quality silicon carbide atomically smooth substrates, and SiC static and dynamic device characterization under elevated temperature conditions. The rationale for and the benefits of developing advanced electrical materials and components for the PMAD subsystem and also for the total power system will also be briefly discussed.

  6. Development of ceramic matrix composites for application in the ceramic technology for advanced heat engines project

    SciTech Connect

    Yeh, H.; Solidum, E.; Karasek, K.; Stranford, G.; Yuhas, D.; Schienle, J.; Bradley, S. . Garrett Ceramic Components Div.)

    1992-04-01

    The objective of this effort (Phase II of a multi-phase program) was to maximize the toughness of a high-temperature Si{sub 3}N{sub 4} (GN-10) by the near-net-shape fabrication technology established previously (Phase I). Acid-etched American Matrix SiC whiskers were selected as the reinforcement. Extensive green forming and densification process optimizations were conducted. The results showed that whisker addition increased the toughness slightly, but decreased the strength of the material. It has been recommended to discontinue the whisker reinforcement approach, and to instead pursue the in-situ grown-whisker reinforcement approach. To address future needs for the composite technology, two supplemental efforts were conducted using monolithic GN-10 Si{sub 3}N{sub 4}. These were nanometer deposition of sintering aids and ultrasonic characterization of drying. Spray drying, polymerization, basic precipitation, and evaporation yielded more uniform sintering aid distributions than conventional ball milling. Spray drying was selected for scale-up study. Improved mechanical properties were demonstrated. The results of the ultrasonic study showed that variations in ultrasonic compressional velocity in slip-cast components are more complex than anticipated. Specifically, it was found that the sonic velocity, as a function of moisture content, was double-valued. This behavior, together with the problems associated with maintaining uniform couplant, precludes the use of ultrasonics as a routine means of monitoring moisture content.

  7. ADVANCED CERAMIC MATERIALS FOR NEXT-GENERATION NUCLEAR APPLICATIONS

    SciTech Connect

    Marra, J.

    2010-09-29

    proliferation), the worldwide community is working to develop and deploy new nuclear energy systems and advanced fuel cycles. These new nuclear systems address the key challenges and include: (1) extracting the full energy value of the nuclear fuel; (2) creating waste solutions with improved long term safety; (3) minimizing the potential for the misuse of the technology and materials for weapons; (4) continually improving the safety of nuclear energy systems; and (5) keeping the cost of energy affordable.

  8. Advanced ceramic coating development for industrial/utility gas turbine applications

    NASA Technical Reports Server (NTRS)

    Andersson, C. A.; Lau, S. K.; Bratton, R. J.; Lee, S. Y.; Rieke, K. L.; Allen, J.; Munson, K. E.

    1982-01-01

    The effects of ceramic coatings on the lifetimes of metal turbine components and on the performance of a utility turbine, as well as of the turbine operational cycle on the ceramic coatings were determined. When operating the turbine under conditions of constant cooling flow, the first row blades run 55K cooler, and as a result, have 10 times the creep rupture life, 10 times the low cycle fatigue life and twice the corrosion life with only slight decreases in both specific power and efficiency. When operating the turbine at constant metal temperature and reduced cooling flow, both specific power and efficiency increases, with no change in component lifetime. The most severe thermal transient of the turbine causes the coating bond stresses to approach 60% of the bond strengths. Ceramic coating failures was studied. Analytic models based on fracture mechanics theories, combined with measured properties quantitatively assessed both single and multiple thermal cycle failures which allowed the prediction of coating lifetime. Qualitative models for corrosion failures are also presented.

  9. Nondestructive Measurements for Diagnostics of Advanced Reactor Passive Components

    SciTech Connect

    Prowant, Matthew S.; Dib, Gerges; Roy, Surajit; Luzi, Lorenzo; Ramuhalli, Pradeep

    2016-09-20

    Information on advanced reactor (AdvRx) component condition and failure probability is necessary to maintaining adequate safety margins and avoiding unplanned shutdowns, both of which have regulatory and economic consequences. Prognostic health management (PHM) technologies provide one approach to addressing these needs by providing the technical means for lifetime management of significant passive components and reactor internals. However, such systems require measurement data that are sensitive to degradation of the component. This paper describes results to date of ongoing research on nondestructive measurements of component condition for degradation mechanisms of relevance to AdvRx concepts. The focus of this paper is on in-situ ultrasonic measurements during high-temperature creep degradation. The data were analyzed to assess the sensitivity of the measurements to creep degradation, with the specific objective of assessing the suitability of the resulting correlations for remaining life prediction. The details of the measurements, results of data analysis, and ongoing research in this area are discussed.

  10. Center for Technology for Advanced Scientific Component Software (TASCS)

    SciTech Connect

    Damevski, Kostadin

    2009-03-30

    A resounding success of the Scientific Discover through Advanced Computing (SciDAC) program is that high-performance computational science is now universally recognized as a critical aspect of scientific discovery [71], complementing both theoretical and experimental research. As scientific communities prepare to exploit unprecedened computing capabilities of emerging leadership-class machines for multi-model simulations at the extreme scale [72], it is more important than ever to address the technical and social challenges of geographically distributed teams that combine expertise in domain science, applied mathematics, and computer science to build robust and flexible codes that can incorporate changes over time. The Center for Technology for Advanced Scientific Component Software (TASCS) tackles these issues by exploiting component-based software development to facilitate collaborative hig-performance scientific computing.

  11. Advances in Ceramic Matrix Composite Blade Damping Characteristics for Aerospace Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    Min, James B.; Harris, Donald L.; Ting, J. M.

    2011-01-01

    For advanced aerospace propulsion systems, development of ceramic matrix composite integrally-bladed turbine disk technology is attractive for a number of reasons. The high strength-to-weight ratio of ceramic composites helps to reduce engine weight and the one-piece construction of a blisk will result in fewer parts count, which should translate into reduced operational costs. One shortcoming with blisk construction, however, is that blisks may be prone to high cycle fatigue due to their structural response to high vibration environments. Use of ceramic composites is expected to provide some internal damping to reduce the vibratory stresses encountered due to unsteady flow loads through the bladed turbine regions. A goal of our research was to characterize the vibration viscous damping behavior of C/SiC composites. The vibration damping properties were measured and calculated. Damping appeared to decrease with an increase in the natural frequency. While the critical damping amount of approximately 2% is required for typical aerospace turbomachinery engines, the C/SiC damping at high frequencies was less than 0.2% from our study. The advanced high-performance aerospace propulsion systems almost certainly will require even more damping than what current vehicles require. A purpose of this paper is to review some work on C/SiC vibration damping by the authors for the NASA CMC turbine blisk development program and address an importance of the further investigation of the blade vibration damping characteristics on candidate CMC materials for the NASA s advanced aerospace turbomachinery engine systems.

  12. Dynamic Fragmentation of an Advanced Ceramic during High-Speed Impact

    NASA Astrophysics Data System (ADS)

    Hogan, James; Farbaniec, Lukasz; Mallick, Debjoy; McCauley, James W.; Ramesh, K. T.; Hopkins Extreme Materials Institute Collaboration

    2015-06-01

    The development of the next generation of light-weight protection materials requires an improved understanding of impact-induced fragmentation of advanced ceramics. We investigate the impact behavior of a hot-pressed boron carbide for impact velocities between 200 and 1000 m/s, and study the response in the context of the material properties, microstructure, and boundary conditions (e.g., confinement). We use measurements of fragment size and shapes to inform us about the mechanisms that are activated during dynamic failure. The fragment measurements are linked with physical evidence of failure processes obtained using scanning electron microscopy and Raman spectroscopy.

  13. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1990-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra-efficient and low-emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttria based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  14. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2003-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra efficient and low emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttna based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  15. Uses of Advanced Ceramic Composites in the Thermal Protection Systems of Future Space Vehicles

    NASA Technical Reports Server (NTRS)

    Rasky, Daniel J.

    1994-01-01

    Current ceramic composites being developed and characterized for use in the thermal protection systems (TPS) of future space vehicles are reviewed. The composites discussed include new tough, low density ceramic insulation's, both rigid and flexible; ultra-high temperature ceramic composites; nano-ceramics; as well as new hybrid ceramic/metallic and ceramic/organic systems. Application and advantage of these new composites to the thermal protection systems of future reusable access to space vehicles and small spacecraft is reviewed.

  16. High speed low damage grinding of advanced ceramics - Phase II Final Report

    SciTech Connect

    Kovach, J.A.; Malkin, S.

    2000-02-01

    In the manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. As a result, one of the most challenging tasks faced by manufacturing process engineers is the development of a ceramic finishing process to maximize part throughput while minimizing costs and associated scrap levels. The efforts summarized in this report represent the second phase of a program whose overall objective was to develop a single-step, roughing-finishing process suitable for producing high-quality silicon nitride parts at high material removal rates and at substantially lower cost than traditional, multi-stage grinding processes. More specifically, this report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding which employs elevated wheel speeds to achieve the small grain depths of cut necessary for low-damage grinding while operating at relatively high material removal rates. The study employed the combined use of laboratory grinding tests, mathematical grinding models, and characterization of the resultant surface condition. A single-step, roughing-finishing process operating at high removal rates was developed and demonstrated.

  17. Integrated nitrogen removal biofilter system with ceramic membrane for advanced post-treatment of municipal wastewater.

    PubMed

    Son, Dong-Jin; Yun, Chan-Young; Kim, Woo-Yeol; Zhang, Xing-Ya; Kim, Dae-Gun; Chang, Duk; Sunwoo, Young; Hong, Ki-Ho

    2016-12-01

    The pre-denitrification biofilm process for nitrogen removal was combined with ceramic membrane with pore sizes of 0.05-0.1 µm as a system for advanced post-treatment of municipal wastewater. The system was operated under an empty bed hydraulic retention time of 7.8 h, recirculation ratio of 3, and transmembrane pressure of 0.47 bar. The system showed average removals of organics, total nitrogen, and solids as high as 93%, 80%, and 100%, respectively. Rapid nitrification could be achieved and denitrification was performed in the anoxic filter without external carbon supplements. The residual particulate organics and nitrogen in effluent from biofilm process could be also removed successfully through membrane filtration and the removal of total coliform was noticeably improved after membrane filtration. Thus, a system composed of the pre-denitrification biofilm process with ceramic membrane would be a compact and flexible option for advanced post-treatment of municipal wastewater.

  18. Reliability Quantification of Advanced Stirling Convertor (ASC) Components

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin R.; Korovaichuk, Igor; Zampino, Edward

    2010-01-01

    The Advanced Stirling Convertor, is intended to provide power for an unmanned planetary spacecraft and has an operational life requirement of 17 years. Over this 17 year mission, the ASC must provide power with desired performance and efficiency and require no corrective maintenance. Reliability demonstration testing for the ASC was found to be very limited due to schedule and resource constraints. Reliability demonstration must involve the application of analysis, system and component level testing, and simulation models, taken collectively. Therefore, computer simulation with limited test data verification is a viable approach to assess the reliability of ASC components. This approach is based on physics-of-failure mechanisms and involves the relationship among the design variables based on physics, mechanics, material behavior models, interaction of different components and their respective disciplines such as structures, materials, fluid, thermal, mechanical, electrical, etc. In addition, these models are based on the available test data, which can be updated, and analysis refined as more data and information becomes available. The failure mechanisms and causes of failure are included in the analysis, especially in light of the new information, in order to develop guidelines to improve design reliability and better operating controls to reduce the probability of failure. Quantified reliability assessment based on fundamental physical behavior of components and their relationship with other components has demonstrated itself to be a superior technique to conventional reliability approaches based on utilizing failure rates derived from similar equipment or simply expert judgment.

  19. Prognostics Health Management for Advanced Small Modular Reactor Passive Components

    SciTech Connect

    Meyer, Ryan M.; Ramuhalli, Pradeep; Coble, Jamie B.; Mitchell, Mark R.; Wootan, David W.; Hirt, Evelyn H.; Berglin, Eric J.; Bond, Leonard J.; Henager, Charles H.

    2013-10-18

    In the United States, sustainable nuclear power to promote energy security is a key national energy priority. Advanced small modular reactors (AdvSMR), which are based on modularization of advanced reactor concepts using non-light-water reactor (LWR) coolants such as liquid metal, helium, or liquid salt may provide a longer-term alternative to more conventional LWR-based concepts. The economics of AdvSMRs will be impacted by the reduced economy-of-scale savings when compared to traditional LWRs and the controllable day-to-day costs of AdvSMRs are expected to be dominated by operations and maintenance costs. Therefore, achieving the full benefits of AdvSMR deployment requires a new paradigm for plant design and management. In this context, prognostic health management of passive components in AdvSMRs can play a key role in enabling the economic deployment of AdvSMRs. In this paper, the background of AdvSMRs is discussed from which requirements for PHM systems are derived. The particle filter technique is proposed as a prognostics framework for AdvSMR passive components and the suitability of the particle filter technique is illustrated by using it to forecast thermal creep degradation using a physics-of-failure model and based on a combination of types of measurements conceived for passive AdvSMR components.

  20. Development of wear-resistant ceramic coatings for diesel engine components

    SciTech Connect

    Naylor, M.G.S. )

    1992-06-01

    The tribological properties of a variety of advanced coating materials have been evaluated under conditions which simulate the piston ring -- cylinder liner environment near top ring reversal in a heavy duty diesel engine. Coated ring'' samples were tested against a conventional pearlitic grey cast iron liner material using a high temperature reciprocating wear test rig. Tests were run with a fresh CE/SF 15W40lubricant at 200 and 350{degrees}C, with a high-soot, engine-tested oil at 200{degrees}C and with no lubrication at 200{degrees}C. For lowest wear under boundary lubricated conditions, the most promising candidates to emerge from this study were high velocity oxy-fuel (HVOF) Cr{sub 3} C{sub 2} - 20% NiCr and WC - 12% Co cermets, low temperature arc vapor deposited (LTAVD) CrN and plasma sprayed chromium oxides. Also,plasma sprayed Cr{sub 2}O{sub 3} and A1{sub 2}O{sub 3}-ZrO{sub 2} materials were found to give excellent wear resistance in unlubricated tests and at extremely high temperatures (450{degrees}C) with a syntheticoil. All of these materials would offer substantial wear reductions compared to the conventional electroplated hard chromium ring facing and thermally sprayed metallic coatings, especially at high temperatures and with high-soot oils subjected to degradation in diesel environments. The LTAVD CrN coating provided the lowest lubricated wear rates of all the materials evaluated, but may be too thin (4 {mu}m) for use as a top ring facing. Most of the coatings evaluated showed higher wear rates with high-soot, engine-tested oil than with fresh oil, with increases of more than a factor of ten in some cases. Generally, metallic materials were found to be much more sensitive to soot/oil degradation than ceramic and cermet coatings. Thus, decreased soot sensitivity'' is a significant driving force for utilizing ceramic or cermet coatings in diesel engine wear applications.

  1. A Method of Producing Surface Conduction on Ceramic Accelerator Components Using Metal Ion Implantation

    SciTech Connect

    Liu, F.; Brown, I.; Phillips, H.; Biallas, George; Siggins, Timothy

    1997-05-01

    An important technique used for the suppression of surface flashover on high voltage DC ceramic insulators as well as for RF windows is that of providing some surface conduction to bleed off accumulated surface charge. We have used metal ion implantation to modify the surface of high voltage ceramic vacuum insulators to provide a niform surface resistivity of approximately 5 x 1010 W/square. A vacuum arc ion source based implanter was used to implant Pt at an energy of about 135 keV to doses of up to more than 5 x 1016 ions/cm2 into small ceramic test coupons and also into the inside surface of several ceramic accelerator columns 25 cm I. D. by 28 cm long. Here we describe the experimental set-up used to do the ion implantation and summarize the results of our exploratory work on implantation into test coupons as well as the implantations of the actual ceramic columns.

  2. Melt processed crystalline ceramic waste forms for advanced nuclear fuel cycles: CRP T21027 1813: Processing technologies for high level waste, formulation of matrices and characterization of waste forms, Task 17208: Final report

    SciTech Connect

    Amoroso, J. W.; Marra, J. C.

    2015-08-26

    A multi-phase ceramic waste form is being developed at the Savannah River National Laboratory (SRNL) for treatment of secondary waste streams generated by reprocessing commercial spent nuclear. The envisioned waste stream contains a mixture of transition, alkali, alkaline earth, and lanthanide metals. Ceramic waste forms are tailored (engineered) to incorporate waste components as part of their crystal structure based on knowledge from naturally found minerals containing radioactive and non-radioactive species similar to the radionuclides of concern in wastes from fuel reprocessing. The ability to tailor ceramics to mimic naturally occurring crystals substantiates the long term stability of such crystals (ceramics) over geologic timescales of interest for nuclear waste immobilization [1]. A durable multi-phase ceramic waste form tailored to incorporate all the waste components has the potential to broaden the available disposal options and thus minimize the storage and disposal costs associated with aqueous reprocessing. This report summarizes results from three years of work on the IAEA Coordinated Research Project on “Processing technologies for high level waste, formulation of matrices and characterization of waste forms” (T21027), and specific task “Melt Processed Crystalline Ceramic Waste Forms for Advanced Nuclear Fuel Cycles” (17208).

  3. Melt processed crystalline ceramic waste forms for advanced nuclear fuel cycles: CRP T21027 1813: Processing technologies for high level waste, formulation of matrices and characterization of waste forms, task 17208: Final report

    SciTech Connect

    Amoroso, J. W.; Marra, J. C.

    2015-08-26

    A multi-phase ceramic waste form is being developed at the Savannah River National Laboratory (SRNL) for treatment of secondary waste streams generated by reprocessing commercial spent nuclear. The envisioned waste stream contains a mixture of transition, alkali, alkaline earth, and lanthanide metals. Ceramic waste forms are tailored (engineered) to incorporate waste components as part of their crystal structure based on knowledge from naturally found minerals containing radioactive and non-radioactive species similar to the radionuclides of concern in wastes from fuel reprocessing. The ability to tailor ceramics to mimic naturally occurring crystals substantiates the long term stability of such crystals (ceramics) over geologic timescales of interest for nuclear waste immobilization [1]. A durable multi-phase ceramic waste form tailored to incorporate all the waste components has the potential to broaden the available disposal options and thus minimize the storage and disposal costs associated with aqueous reprocessing. This report summarizes results from three years of work on the IAEA Coordinated Research Project on “Processing technologies for high level waste, formulation of matrices and characterization of waste forms” (T21027), and specific task “Melt Processed Crystalline Ceramic Waste Forms for Advanced Nuclear Fuel Cycles” (17208).

  4. Hydrogen-bromine fuel cell advance component development

    NASA Technical Reports Server (NTRS)

    Charleston, Joann; Reed, James

    1988-01-01

    Advanced cell component development is performed by NASA Lewis to achieve improved performance and longer life for the hydrogen-bromine fuel cells system. The state-of-the-art hydrogen-bromine system utilizes the solid polymer electrolyte (SPE) technology, similar to the SPE technology developed for the hydrogen-oxygen fuel cell system. These studies are directed at exploring the potential for this system by assessing and evaluating various types of materials for cell parts and electrode materials for Bromine-hydrogen bromine environment and fabricating experimental membrane/electrode-catalysts by chemical deposition.

  5. Advancements in all-ceramics for dental restorations and their effect on the wear of opposing dentition

    PubMed Central

    Rashid, Haroon; Sheikh, Zeeshan; Misbahuddin, Syed; Kazmi, Murtaza Raza; Qureshi, Sameer; Uddin, Muhammad Zuhaib

    2016-01-01

    Tooth wear is a process that is usually a result of tooth to tooth and/or tooth and restoration contact. The process of wear essentially becomes accelerated by the introduction of restorations inside the oral cavity, especially in case of opposing ceramic restorations. The newest materials have vastly contributed toward the interest in esthetic dental restorations and have been extensively studied in laboratories. However, despite the recent technological advancements, there has not been a valid in vivo method of evaluation involving clinical wear caused due to ceramics upon restored teeth and natural dentition. The aim of this paper is to review the latest advancements in all-ceramic materials, and their effect on the wear of opposing dentition. The descriptive review has been written after a thorough MEDLINE/PubMed search by the authors. It is imperative that clinicians are aware of recent advancements and that they should always consider the type of ceramic restorative materials used to maintain a stable occlusal relation. The ceramic restorations should be adequately finished and polished after the chair-side adjustment process of occlusal surfaces. PMID:28042280

  6. Application of advanced austenitic alloys to fossil power system components

    SciTech Connect

    Swindeman, R.W.

    1996-06-01

    Most power and recovery boilers operating in the US produce steam at temperatures below 565{degrees}C (1050{degrees}F) and pressures below 24 MPa (3500 psi). For these operating conditions, carbon steels and low alloy steels may be used for the construction of most of the boiler components. Austenitic stainless steels often are used for superheater/reheater tubing when these components are expected to experience temperatures above 565{degrees}C (1050{degrees}F) or when the environment is too corrosive for low alloys steels. The austenitic stainless steels typically used are the 304H, 321H, and 347H grades. New ferritic steels such as T91 and T92 are now being introduced to replace austenitic: stainless steels in aging fossil power plants. Generally, these high-strength ferritic steels are more expensive to fabricate than austenitic stainless steels because the ferritic steels have more stringent heat treating requirements. Now, annealing requirements are being considered for the stabilized grades of austenitic stainless steels when they receive more than 5% cold work, and these requirements would increase significantly the cost of fabrication of boiler components where bending strains often exceed 15%. It has been shown, however, that advanced stainless steels developed at ORNL greatly benefit from cold work, and these steels could provide an alternative to either conventional stainless steels or high-strength ferritic steels. The purpose of the activities reported here is to examine the potential of advanced stainless steels for construction of tubular components in power boilers. The work is being carried out with collaboration of a commercial boiler manufacturer.

  7. Influence of ceramic package internal components on the performance of vacuum sealed uncooled bolometric detectors

    NASA Astrophysics Data System (ADS)

    Paquet, Alex; Deshaies, Sébastien; Desroches, Yan; Whalin, Jeff; Topart, Patrice

    2013-03-01

    INO has developed a hermetic vacuum packaging technology for uncooled bolometric detectors based on ceramic leadless chip carriers (LCC). Cavity pressures less than 3 mTorr are obtained. Processes are performed in a state-of-the art semi-automated vacuum furnace that allows for independent activation of non-evaporable thin film getters. The getter activation temperature is limited by both the anti-reflection coated silicon or germanium window and the MEMS device built on CMOS circuits. Temperature profiles used to achieve getter activation and vacuum sealing were optimized to meet lifetime and reliability requirements of packaged devices. Internal package components were carefully selected with respect to their outgassing behavior so that a good vacuum performance was obtained. In this paper, INO's packaging process is described. The influence of various package internal components, in particular the CMOS circuits, on vacuum performance is presented. The package cavity pressure was monitored using INO's pressure microsensors and the gas composition was determined by internal vapor analysis. Lifetime was derived from accelerated testing after storage of packaged detectors at various temperatures from room temperature to 120°C. A hermeticity yield over 80% was obtained for batches of twelve devices packaged simultaneously. Packaged FPAs submitted to standard MIL-STD-810 reliability testing (vibration, shock and temperature cycling) exhibited no change in IR response. Results show that vacuum performance strongly depends on CMOS circuit chips. Detectors packaged using a thin film getter show no change in cavity pressure after storage for more than 30 days at 120°C. Moreover, INO's vacuum sealing process is such that even without a thin film getter, a base pressure of less than 10 mTorr is obtained and no pressure change is observed after 40 days at 85°C.

  8. Ceramic Processing

    SciTech Connect

    EWSUK,KEVIN G.

    1999-11-24

    Ceramics represent a unique class of materials that are distinguished from common metals and plastics by their: (1) high hardness, stiffness, and good wear properties (i.e., abrasion resistance); (2) ability to withstand high temperatures (i.e., refractoriness); (3) chemical durability; and (4) electrical properties that allow them to be electrical insulators, semiconductors, or ionic conductors. Ceramics can be broken down into two general categories, traditional and advanced ceramics. Traditional ceramics include common household products such as clay pots, tiles, pipe, and bricks, porcelain china, sinks, and electrical insulators, and thermally insulating refractory bricks for ovens and fireplaces. Advanced ceramics, also referred to as ''high-tech'' ceramics, include products such as spark plug bodies, piston rings, catalyst supports, and water pump seals for automobiles, thermally insulating tiles for the space shuttle, sodium vapor lamp tubes in streetlights, and the capacitors, resistors, transducers, and varistors in the solid-state electronics we use daily. The major differences between traditional and advanced ceramics are in the processing tolerances and cost. Traditional ceramics are manufactured with inexpensive raw materials, are relatively tolerant of minor process deviations, and are relatively inexpensive. Advanced ceramics are typically made with more refined raw materials and processing to optimize a given property or combination of properties (e.g., mechanical, electrical, dielectric, optical, thermal, physical, and/or magnetic) for a given application. Advanced ceramics generally have improved performance and reliability over traditional ceramics, but are typically more expensive. Additionally, advanced ceramics are typically more sensitive to the chemical and physical defects present in the starting raw materials, or those that are introduced during manufacturing.

  9. Ceramic Technology Project semiannual progress report, April 1992--September 1992

    SciTech Connect

    Johnson, D.R.

    1993-07-01

    This project was developed to meet the ceramic technology requirements of the DOE Office of Transportation Systems` automotive technology programs. Significant progress in fabricating ceramic components for DOE, NASA, and DOE advanced heat engine programs show that operation of ceramic parts in high-temperature engines is feasible; however, addition research is needed in materials and processing, design, and data base and life prediction before industry will have a sufficient technology base for producing reliable cost-effective ceramic engine components commercially. A 5-yr project plan was developed, with focus on structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines.

  10. Environmental Barrier Coating Development for SiC/SiC Ceramic Matrix Composites: Recent Advances and Future Directions

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming

    2016-01-01

    This presentation briefly reviews the SiC/SiC major environmental and environment-fatigue degradations encountered in simulated turbine combustion environments, and thus NASA environmental barrier coating system evolution for protecting the SiC/SiC Ceramic Matrix Composites for meeting the engine performance requirements. The presentation will review several generations of NASA EBC materials systems, EBC-CMC component system technologies for SiC/SiC ceramic matrix composite combustors and turbine airfoils, highlighting the temperature capability and durability improvements in simulated engine high heat flux, high pressure, high velocity, and with mechanical creep and fatigue loading conditions. This paper will also focus on the performance requirements and design considerations of environmental barrier coatings for next generation turbine engine applications. The current development emphasis is placed on advanced NASA candidate environmental barrier coating systems for SiC/SiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. The efforts have been also directed to developing prime-reliant, self-healing 2700F EBC bond coat; and high stability, lower thermal conductivity, and durable EBC top coats. Major technical barriers in developing environmental barrier coating systems, the coating integrations with next generation CMCs having the improved environmental stability, erosion-impact resistance, and long-term fatigue-environment system durability performance will be described. The research and development opportunities for turbine engine environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling will be briefly discussed.

  11. Ceramics for the advanced automotive gas turbine engine: A look at a single shaft design

    NASA Technical Reports Server (NTRS)

    Nosek, S. M.

    1977-01-01

    The results of a preliminary analysis of a single shaft regenerative design with a single stage radial turbine are presented to show the fuel economy that can be achieved at high turbine inlet temperatures, with this particular advanced design, if the turbine tip speed and regenerator inlet temperature are not limited. The engine size was 100 hp for application to a 3500 lb auto. The fuel economy was analyzed by coupling the engine to the auto through a continuously variable speed-ratio transmission and operating the system at constant turbine inlet temperature over the Composite Driving Cycle. The fuel was gasoline and the analysis was for a 85 F day. With a turbine inlet temperature of 2500 F the fuel economy was 26.2 mpg, an improvement of 18 percent over that of 22.3 mpg with a turbine inlet temperature of 1900 F. The turbine tip speed needed for best economy with the 2500 F engine was 2530 ft/sec. The regenerator temperature was approximately 2200 F at idle. Disk stresses were estimated for one single stage radial turbine and two two-stage radial-axial turbines and compared with maximum allowable stress curves estimated for a current ceramic material. Results show a need for higher Weibull Modulus, higher strength ceramics.

  12. DEVELOPMENT OF CRYSTALLINE CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES

    SciTech Connect

    Fox, K.; Brinkman, K.

    2011-09-22

    The Savannah River National Laboratory (SRNL) is developing crystalline ceramic waste forms to incorporate CS/LN/TM high Mo waste streams consisting of perovskite, hollandite, pyrochlore, zirconolite, and powellite phase assemblages. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase crystalline ceramics. Fiscal Year 2011 (FY11) activities included (i) expanding the compositional range by varying waste loading and fabrication of compositions rich in TiO{sub 2}, (ii) exploring the processing parameters of ceramics produced by the melt and crystallize process, (iii) synthesis and characterization of select individual phases of powellite and hollandite that are the target hosts for radionuclides of Mo, Cs, and Rb, and (iv) evaluating the durability and radiation stability of single and multi-phase ceramic waste forms. Two fabrication methods, including melting and crystallizing, and pressing and sintering, were used with the intent of studying phase evolution under various sintering conditions. An analysis of the XRD and SEM/EDS results indicates that the targeted crystalline phases of the FY11 compositions consisting of pyrochlore, perovskite, hollandite, zirconolite, and powellite were formed by both press and sinter and melt and crystallize processing methods. An evaluation of crystalline phase formation versus melt processing conditions revealed that hollandite, perovskite, zirconolite, and residual TiO{sub 2} phases formed regardless of cooling rate, demonstrating the robust nature of this process for crystalline phase development. The multiphase ceramic composition CSLNTM-06 demonstrated good resistance to proton beam irradiation. Electron irradiation studies on the single phase CaMoO{sub 4} (a component of the multiphase waste form) suggested that this material exhibits stability to 1000 years at anticipated self-irradiation doses (2 x 10{sup 10}-2 x 10{sup 11} Gy), but that

  13. High-Performance SiC/SiC Ceramic Composite Systems Developed for 1315 C (2400 F) Engine Components

    NASA Technical Reports Server (NTRS)

    DiCarlo, James A.; Yun, Hee Mann; Morscher, Gregory N.; Bhatt, Ramakrishna T.

    2004-01-01

    As structural materials for hot-section components in advanced aerospace and land-based gas turbine engines, silicon carbide (SiC) ceramic matrix composites reinforced by high performance SiC fibers offer a variety of performance advantages over current bill-of-materials, such as nickel-based superalloys. These advantages are based on the SiC/SiC composites displaying higher temperature capability for a given structural load, lower density (approximately 30- to 50-percent metal density), and lower thermal expansion. These properties should, in turn, result in many important engine benefits, such as reduced component cooling air requirements, simpler component design, reduced support structure weight, improved fuel efficiency, reduced emissions, higher blade frequencies, reduced blade clearances, and higher thrust. Under the NASA Ultra-Efficient Engine Technology (UEET) Project, much progress has been made at the NASA Glenn Research Center in identifying and optimizing two highperformance SiC/SiC composite systems. The table compares typical properties of oxide/oxide panels and SiC/SiC panels formed by the random stacking of balanced 0 degrees/90 degrees fabric pieces reinforced by the indicated fiber types. The Glenn SiC/SiC systems A and B (shaded area of the table) were reinforced by the Sylramic-iBN SiC fiber, which was produced at Glenn by thermal treatment of the commercial Sylramic SiC fiber (Dow Corning, Midland, MI; ref. 2). The treatment process (1) removes boron from the Sylramic fiber, thereby improving fiber creep, rupture, and oxidation resistance and (2) allows the boron to react with nitrogen to form a thin in situ grown BN coating on the fiber surface, thereby providing an oxidation-resistant buffer layer between contacting fibers in the fabric and the final composite. The fabric stacks for all SiC/SiC panels were provided to GE Power Systems Composites for chemical vapor infiltration of Glenn designed BN fiber coatings and conventional SiC matrices

  14. Power Law Versus Exponential Form of Slow Crack Growth of Advanced Structural Ceramics: Dynamic Fatigue

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.

    2002-01-01

    The life prediction analysis based on an exponential crack velocity formulation was examined using a variety of experimental data on glass and advanced structural ceramics in constant stress-rate ("dynamic fatigue") and preload testing at ambient and elevated temperatures. The data fit to the strength versus In (stress rate) relation was found to be very reasonable for most of the materials. It was also found that preloading technique was equally applicable for the case of slow crack growth (SCG) parameter n > 30. The major limitation in the exponential crack velocity formulation, however, was that an inert strength of a material must be known priori to evaluate the important SCG parameter n, a significant drawback as compared to the conventional power-law crack velocity formulation.

  15. ENERGY EFFICIENCY CHALLENGES ADDRESSED THROUGH THE USE OF ADVANCED REFRACTORY CERAMIC MATERIALS

    SciTech Connect

    Hemrick, James Gordon

    2014-01-01

    Refractory ceramics can play a critical role in improving the energy efficiency of traditional industrial processes through increased furnace efficiency brought about by the employment of novel refractory systems and techniques. Examples of advances in refractory materials related to aluminum, gasification, glass, and lime are highlighted. Energy savings are realized based on reduction of chemical reactions, elimination of mechanical degradation caused by the service environment, reduction of temperature limitations of materials, and elimination of costly installation and repair needs. Key results of projects resulting from US Department of Energy (DOE) funded research programs are discussed with emphasis on applicability of these results to high temperature furnace applications and needed research directions for the future.

  16. Reducing the Scatter in Reliability Predictions for Ceramic Components Using a Combined MCMC and BOOTSTRAP Approach

    SciTech Connect

    Roudi, S.; Riesch-Oppermann, H.

    2004-11-16

    Reliability of ceramic components is usually obtained in terms of failure probability from Finite Element stress analysis and subsequent numerical integration of the stress field. Due to scatter in the material parameters that enter the numerical integration, the uncertainty in the resulting failure probabilities depends strongly on the quality and abundance of the underlying data base. Material parameters that enter the calculation are obtained at different levels of, e.g. temperature or loading rate. It would be helpful to have a framework which allows efficient allocation of specimens to different types of experiments with respect to minimizing the resulting scatter in the failure probability predictions.For the prediction of confidence intervals for the failure probability, we use bootstrap resampling methods based on observed samples for material strength measurements. For the description of temperature dependent material behavior we have implemented two methods for regression neural networks, namely D. J. C. MacKay's Gaussian approximation method and also Markov Chain Monte Carlo Method of R. M. Neal.This procedure allows also a 'pooling' of the data -- in our case we obtain one large room temperature sample from various samples at different temperatures -- leading to reduced prediction uncertainty. Using the regression network, we can generate a relation between the strength data base and the corresponding reliability prediction uncertainty. In order to investigate the influence of different data bases, we use a parametric bootstrap approach to generate artificial samples from the original data. Imposing weights to different samples, a procedure is obtained which detects the relevance of specific samples to the uncertainties in the final failure probability prediction.Thus strategies can be proposed for efficient allocation of available specimens to selected experimental conditions.

  17. Advanced materials: The fabrication, characterization and study of novel ceramics and composites

    NASA Astrophysics Data System (ADS)

    Pitcher, Michael W.

    As advances in technology prompt demands for materials with specific and wide ranges of properties, traditional materials have often not been able to meet these more challenging needs. There is also an exigency to process these materials with minimal consumption of energy at low cost. To address these needs there has been a considerable impetus to develop new materials, new processing strategies and/or new synthetic strategies. This thesis focuses on the synthesis, characterization, and manipulation of a variety of new and advanced materials. The two main topics of this thesis are, firstly, a composite system where the growth of an inorganic phase takes place within a polymer film. Composite films of CdS in PEO were formed by an in situ reaction of CdCl2/PEO composite films with an octane solution of hexamethyldisilathiane [S(TMS) 2]. Organized crystallization of the product was found only to occur in thin films (<300nm) in the presence of surfactant. Crystals were found to be uniform in size, shape, phase and crystallographic orientation. The principles of this system have been further developed and used to produce novel phases of lead sulfides at room temperature and pressure, and the first known synthesis of single crystals of Lithium Niobate at room temperature and pressure. The second part of this thesis deals with the synthesis and characterization of poly(methyl)silyne (PMSy), a polymer precursor to silicon carbide (SiC). The synthesis of PMSy is both cheap and simple. The polymer is non-pyrophoric which is unique among current SiC preceramic polymers. The pyrolysis of PMSy results in a ceramic of unrivaled purity, it is the only perfectly stoichiometric SiC than has been obtained from any polymeric precursor. Ceramic films have also been produced from PMSy, and are the smoothest, the most continuous, the most perfect and defect free that have ever been reported.

  18. PRELIMINARY STUDY OF CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES

    SciTech Connect

    Fox, K.; Billings, A.; Brinkman, K.; Marra, J.

    2010-09-22

    The Savannah River National Laboratory (SRNL) developed a series of ceramic waste forms for the immobilization of Cesium/Lanthanide (CS/LN) and Cesium/Lanthanide/Transition Metal (CS/LN/TM) waste streams anticipated to result from nuclear fuel reprocessing. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase ceramics containing hollandite-type phases, perovskites (particularly BaTiO{sub 3}), pyrochlores, zirconolite, and other minor metal titanate phases. Identification of excess Al{sub 2}O{sub 3} via X-ray Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) in the first series of compositions led to a Phase II study, with significantly reduced Al{sub 2}O{sub 3} concentrations and increased waste loadings. Three fabrication methodologies were used, including melting and crystallizing, pressing and sintering, and Spark Plasma Sintering (SPS), with the intent of studying phase evolution under various sintering conditions. XRD and SEM/EDS results showed that the partitioning of the waste elements in the sintered materials was very similar, despite varying stoichiometry of the phases formed. The Phase II compositions generally contained a reduced amount of unreacted Al{sub 2}O{sub 3} as identified by XRD, and had phase assemblages that were closer to the initial targets. Chemical composition measurements showed no significant issues with meeting the target compositions. However, volatilization of Cs and Mo was identified, particularly during melting, since sintering of the pressed pellets and SPS were performed at lower temperatures. Partitioning of some of the waste components was difficult to determine via XRD. SEM/EDS mapping showed that those elements, which were generally present in small concentrations, were well distributed throughout the waste forms. Initial studies of radiation damage tolerance using ion beam irradiation at Los

  19. Progress in SiC/SiC Ceramic Composite Development for Gas Turbine Hot-Section Components under NASA EPM and UEET Programs

    NASA Technical Reports Server (NTRS)

    DiCarlo, J. A.; Yun, Hee Mann; Morscher, Gregory N.; Bhatt, Ramakrishna T.

    2002-01-01

    The successful application of ceramic matrix composites as hot-section components in advanced gas turbine engines will require the development of constituent materials and processes that can provide the material systems with the key thermostructural properties required for long-term component service. Much initial progress in identifying these materials and processes was made under the former NASA Enabling Propulsion Materials Program using stoichiometric Sylramic (trademark) silicon-carbide (SiC) fibers, 2D (two dimensional)-woven fiber architectures, chemically vapor-infiltrated (CVI) BN fiber coatings (interphases), and SiC-based matrices containing CVI SiC interphase over-coatings, slurry-infiltrated SiC particulate, and melt-infiltrated (MI) silicon. The objective of this paper is to discuss the property benefits of this SiC/SiC composite system for high-temperature engine components and to elaborate on further progress in SiC/SiC development made under the new NASA Ultra Efficient Engine Technology Program. This progress stems from the recent development of advanced constituent materials and manufacturing processes, including specific treatments at NASA that improve the creep, rupture, and environmental resistance of the Sylramic fiber as well as the thermal conductivity and creep resistance of the CVI SiC over-coatings. Also discussed are recent observations concerning the detrimental effects of inadvertent carbon in the fiber-BN interfacial region and the beneficial effects of certain 2D-architectures for thin-walled SiC/SiC panels.

  20. DEVELOPMENT OF CERAMIC WASTE FORMS FOR AN ADVANCED NUCLEAR FUEL CYCLE

    SciTech Connect

    Marra, J.; Billings, A.; Brinkman, K.; Fox, K.

    2010-11-30

    A series of ceramic waste forms were developed and characterized for the immobilization of a Cesium/Lanthanide (CS/LN) waste stream anticipated to result from nuclear fuel reprocessing. Simple raw materials, including Al{sub 2}O{sub 3} and TiO{sub 2} were combined with simulated waste components to produce multiphase ceramics containing hollandite-type phases, perovskites (particularly BaTiO{sub 3}), pyrochlores and other minor metal titanate phases. Three fabrication methodologies were used, including melting and crystallizing, pressing and sintering, and Spark Plasma Sintering (SPS), with the intent of studying phase evolution under various sintering conditions. X-Ray Diffraction (XRD) and Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM/EDS) results showed that the partitioning of the waste elements in the sintered materials was very similar, despite varying stoichiometry of the phases formed. Identification of excess Al{sub 2}O{sub 3} via XRD and SEM/EDS in the first series of compositions led to a Phase II study, with significantly reduced Al{sub 2}O{sub 3} concentrations and increased waste loadings. The Phase II compositions generally contained a reduced amount of unreacted Al{sub 2}O{sub 3} as identified by XRD. Chemical composition measurements showed no significant issues with meeting the target compositions. However, volatilization of Cs and Mo was identified, particularly during melting, since sintering of the pressed pellets and SPS were performed at lower temperatures. Partitioning of some of the waste components was difficult to determine via XRD. SEM/EDS mapping showed that those elements, which were generally present in small concentrations, were well distributed throughout the waste forms.

  1. Ceramic-coated components for the combustion zone of natural gas engines

    NASA Astrophysics Data System (ADS)

    Holloman, L.; Levy, A. V.

    1992-03-01

    The use of ceramic coatings on the combustion zone surfaces of large,natural gas-fueled,internal com-bustion engines is discussed. Unique handling and quality control systems are required for plasma spray-ing thin (0.25 mm,0.0010) in.coatings on up to 48.25(cm19)-in.diameter piston crowns and cylinder heads weighing up to(1200 lb).The in-service performance characteristics of two types of natural gas-fu-eled combustion engines powering natural gas compressors that had thin zirconia ceramic coatings ap-plied to their combustion zone surfaces are presented. Their performance was measured in the field be-fore and after coating. It was determined that the durability,power output,fuel consumption,exhaust emissions,and other operating characteristics all improved due to ceramic coating of the flame side sur-faces of cylinder heads,power pistons,and valves.

  2. Ceramic inspection system

    DOEpatents

    Werve, Michael E.

    2006-05-16

    A system for inspecting a ceramic component. The ceramic component is positioned on a first rotary table. The first rotary table rotates the ceramic component. Light is directed toward the first rotary table and the rotating ceramic component. A detector is located on a second rotary table. The second rotary table is operably connected to the first rotary table and the rotating ceramic component. The second rotary table is used to move the detector at an angle to the first rotary table and the rotating ceramic component.

  3. Reactive Processing of Environment Conscious, Biomorphic Ceramics: A Novel and Eco-friendly Route to Advanced Ceramic

    NASA Technical Reports Server (NTRS)

    Singh, M.

    2002-01-01

    Environment-conscious, biomorphic ceramics (Ecoceramics) are a new class of materials that can be produced with renewable resources (wood) and wood wastes (wood sawdust). These materials have tailorable properties with numerous potential applications. Silicon carbide-based ecoceramics have been fabricated by the infiltration of wood-derived carbonaceous preforms with oxide and silicon based materials. The wood-derived carbonaceous preforms have been shown to be quite useful in producing porous or dense materials with different microstructures and compositions. The microstructure and mechanical properties (flexural strength, fracture toughness, elastic modulus, and compressive strength) of a wide variety of Sic-based ecoceramics have been measured. Ecoceramics have tailorable properties and behave like ceramic materials manufactured by conventional approaches. In this presentation the fabrication approach, microstructure, and thermomechanical properties of a wide variety of Sic-based Ecoceramics will be reported.

  4. Advanced Turbine Technology Applications Project (ATTAP)

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advanced Turbine Technology Application Project (ATTAP) activities during the past year were highlighted by test-bed engine design and development activities; ceramic component design; materials and component characterization; ceramic component process development and fabrication; component rig testing; and test-bed engine fabrication and testing. Although substantial technical challenges remain, all areas exhibited progress. Test-bed engine design and development activity included engine mechanical design, power turbine flow-path design and mechanical layout, and engine system integration aimed at upgrading the AGT-5 from a 1038 C metal engine to a durable 1371 C structural ceramic component test-bed engine. ATTAP-defined ceramic and associated ceramic/metal component design activities include: the ceramic combustor body, the ceramic gasifier turbine static structure, the ceramic gasifier turbine rotor, the ceramic/metal power turbine static structure, and the ceramic power turbine rotors. The materials and component characterization efforts included the testing and evaluation of several candidate ceramic materials and components being developed for use in the ATTAP. Ceramic component process development and fabrication activities are being conducted for the gasifier turbine rotor, gasifier turbine vanes, gasifier turbine scroll, extruded regenerator disks, and thermal insulation. Component rig testing activities include the development of the necessary test procedures and conduction of rig testing of the ceramic components and assemblies. Four-hundred hours of hot gasifier rig test time were accumulated with turbine inlet temperatures exceeding 1204 C at 100 percent design gasifier speed. A total of 348.6 test hours were achieved on a single ceramic rotor without failure and a second ceramic rotor was retired in engine-ready condition at 364.9 test hours. Test-bed engine fabrication, testing, and development supported improvements in ceramic component technology

  5. Thermal stress analysis of ceramic gas-path seal components for aircraft turbines

    NASA Technical Reports Server (NTRS)

    Kennedy, F. E.; Bill, R. C.

    1979-01-01

    Stress and temperature distributions were evaluated numerically for a blade-tip seal system proposed for gas turbine applications. The seal consists of an abradable ceramic layer on metallic backing with intermediate layers between the ceramic layer and metal substrate. The most severe stresses in the seal, as far as failure is concerned, are tensile stresses at the top of the ceramic layer and shear and normal stresses at the layer interfaces. All these stresses reach their maximum values during the deceleration phase of a test engine cycle. A parametric study was carried out to evaluate the influence of various design parameters on these critical stress values. The influences of material properties and geometric parameters of the ceramic, intermediate, and backing layers were investigated. After the parametric study was completed, a seal system was designed which incorporated materials with beneficial elastic and thermal properties in each layer of the seal. An analysis of the proposed seal design shows an appreciable decrease in the magnitude of the maximum critical stresses over those obtained with earlier configurations.

  6. Nondestructive characterization of micromachined ceramics

    NASA Astrophysics Data System (ADS)

    Cooney, Adam; Hix, Kenneth E.; Yaney, Perry; Zhan, Qiwen; Dosser, Larry R.; Blackshire, James L.

    2005-05-01

    The aerospace, automotive, and electronic industries are finding increasing need for components made from silicon carbide (SiC) and silicon nitride (Si3N4). The development and use of miniaturized ceramic parts, in particular, is of significant interest in a variety of critical applications. As these application areas grow, manufacturers are being asked to find new and better solutions for machining and forming ceramic materials with microscopic precision. Recent advances in laser machining technologies are making precision micromachining of ceramics a reality. Questions regarding micromachining accuracy, residual melt region effects, and laser-induced microcracking are of critical concern during the machining process. In this activity, a variety of nondestructive inspection methods have been used to investigate the microscopic features of laser-machined ceramic components. The primary goal was to assess the micromachined areas for machining accuracy and microcracking using laser ultrasound, scanning electron microscopy, and white-light interference microscopic imaging of the machined regions.

  7. Structural ceramics

    NASA Technical Reports Server (NTRS)

    Craig, Douglas F.

    1992-01-01

    This presentation gives a brief history of the field of materials sciences and goes on to expound the advantages of the fastest growing area in that field, namely ceramics. Since ceramics are moving to fill the demand for lighter, stronger, more corrosion resistant materials, advancements will rely more on processing and modeling from the atomic scale up which is made possible by advanced analytical, computer, and processing techniques. All information is presented in viewgraph format.

  8. 24 CFR 242.47 - Insured advances for building components stored off-site.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... components stored off-site. 242.47 Section 242.47 Housing and Urban Development Regulations Relating to... for building components stored off-site. (a) Building components. In insured advances for building components stored off-site, the term building component shall mean any manufactured or pre-assembled part...

  9. 24 CFR 242.47 - Insured advances for building components stored off-site.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... components stored off-site. 242.47 Section 242.47 Housing and Urban Development Regulations Relating to... for building components stored off-site. (a) Building components. In insured advances for building components stored off-site, the term building component shall mean any manufactured or pre-assembled part...

  10. Prototype Development of Remote Operated Hot Uniaxial Press (ROHUP) to Fabricate Advanced Tc-99 Bearing Ceramic Waste Forms - 13381

    SciTech Connect

    Alaniz, Ariana J.; Delgado, Luc R.; Werbick, Brett M.; Hartmann, Thomas

    2013-07-01

    The objective of this senior student project is to design and build a prototype construction of a machine that simultaneously provides the proper pressure and temperature parameters to sinter ceramic powders in-situ to create pellets of rather high densities of above 90% (theoretical). This ROHUP (Remote Operated Hot Uniaxial Press) device is designed specifically to fabricate advanced ceramic Tc-99 bearing waste forms and therefore radiological barriers have been included in the system. The HUP features electronic control and feedback systems to set and monitor pressure, load, and temperature parameters. This device operates wirelessly via portable computer using Bluetooth{sup R} technology. The HUP device is designed to fit in a standard atmosphere controlled glove box to further allow sintering under inert conditions (e.g. under Ar, He, N{sub 2}). This will further allow utilizing this HUP for other potential applications, including radioactive samples, novel ceramic waste forms, advanced oxide fuels, air-sensitive samples, metallic systems, advanced powder metallurgy, diffusion experiments and more. (authors)

  11. National Center for Advanced Information Components Manufacturing. Program summary report, Volume 1

    SciTech Connect

    1996-10-01

    The National Center for Advanced Information Components Manufacturing focused on manufacturing research and development for flat panel displays, advanced lithography, microelectronics, and optoelectronics. This report provides an overview of the program, summaries of the technical projects, and key program accomplishments.

  12. Advances in Understanding of Swift Heavy-Ion Tracks in Complex Ceramics

    SciTech Connect

    Lang, Maik; Devanathan, Ram; Toulemonde, Marcel; Trautmann, Christina

    2015-02-01

    Tracks produced by swift heavy ions in ceramics are of interest for fundamental science as well as for applications covering different fields such as nanotechnology or fission-track dating of minerals. In the case of pyrochlores with general formula A2B2O7, the track structure and radiation sensitivity shows a clear dependence on the composition. Ion irradiated Gd2Zr2O7, e.g., retains its crystallinity while amorphous tracks are produced in Gd2Ti2O7. Tracks in Ti-containing compositions have a complex morphology consisting of an amorphous core surrounded by a shell of a disordered, defect-fluorite phase. The size of the amorphous core decreases with decreasing energy loss and with increasing Zr content, while the shell thickness seems to be similar over a wide range of energy loss values. The large data set and the complex track structure has made pyrochlore an interesting model system for a general theoretical description of track formation including thermal spike calculations (providing the spatial and temporal evolution of temperature around the ion trajectory) and molecular dynamics (MD) simulations (describing the response of the atomic system).Recent MD advances consider the sudden temperature increase by inserting data from the thermal spike. The combination allows the reproduction of the core-shell track characteristic and sheds light on the early stages of track formation including recrystallization of the molten material produced by the thermal spike.

  13. DEVELOPMENT OF ADVANCED DRILL COMPONENTS FOR BHA USING MICROWAVE TECHNOLOGY INCORPORATING CARBIDE, DIAMOND COMPOSITES AND FUNCTIONALLY GRADED MATERIALS

    SciTech Connect

    Dinesh Agrawal; Rustum Roy

    2003-01-01

    The microwave processing of materials is a new emerging technology with many attractive advantages over the conventional methods. The advantages of microwave technology for various ceramic systems has already been demonstrated and proven. The recent developments at Penn State have succeeded in applying the microwave technology for the commercialization of WC/Co and diamond based cutting and drilling tools, effectively sintering of metallic materials, and fabrication of transparent ceramics for advanced applications. In recent years, the Microwave Processing and Engineering Center at Penn State University in collaboration with our industrial partner, Dennis Tool Co. has succeeded in commercializing the developed microwave technology partially funded by DOE for WC/Co and diamond based cutting and drilling tools for gas and oil exploration operations. In this program we have further developed this technology to make diamond-carbide composites and metal-carbide-diamond functionally graded materials. Several actual product of diamond-carbide composites have been processed in microwave with better performance than the conventional product. The functionally graded composites with diamond as one of the components has been for the first time successfully developed. These are the highlights of the project.

  14. Prediction of Corrosion of Advanced Materials and Fabricated Components

    SciTech Connect

    A. Anderko; G. Engelhardt; M.M. Lencka; M.A. Jakab; G. Tormoen; N. Sridhar

    2007-09-29

    The goal of this project is to provide materials engineers, chemical engineers and plant operators with a software tool that will enable them to predict localized corrosion of process equipment including fabricated components as well as base alloys. For design and revamp purposes, the software predicts the occurrence of localized corrosion as a function of environment chemistry and assists the user in selecting the optimum alloy for a given environment. For the operation of existing plants, the software enables the users to predict the remaining life of equipment and help in scheduling maintenance activities. This project combined fundamental understanding of mechanisms of corrosion with focused experimental results to predict the corrosion of advanced, base or fabricated, alloys in real-world environments encountered in the chemical industry. At the heart of this approach is the development of models that predict the fundamental parameters that control the occurrence of localized corrosion as a function of environmental conditions and alloy composition. The fundamental parameters that dictate the occurrence of localized corrosion are the corrosion and repassivation potentials. The program team, OLI Systems and Southwest Research Institute, has developed theoretical models for these parameters. These theoretical models have been applied to predict the occurrence of localized corrosion of base materials and heat-treated components in a variety of environments containing aggressive and non-aggressive species. As a result of this project, a comprehensive model has been established and extensively verified for predicting the occurrence of localized corrosion as a function of environment chemistry and temperature by calculating the corrosion and repassivation potentials.To support and calibrate the model, an experimental database has been developed to elucidate (1) the effects of various inhibiting species as well as aggressive species on localized corrosion of nickel

  15. Development of wear-resistant ceramic coatings for diesel engine components. Volume 1, Coating development and tribological testing: Final report: DOE/ORNL Ceramic Technology Project

    SciTech Connect

    Naylor, M.G.S.

    1992-06-01

    The tribological properties of a variety of advanced coating materials have been evaluated under conditions which simulate the piston ring -- cylinder liner environment near top ring reversal in a heavy duty diesel engine. Coated ``ring`` samples were tested against a conventional pearlitic grey cast iron liner material using a high temperature reciprocating wear test rig. Tests were run with a fresh CE/SF 15W40lubricant at 200 and 350{degrees}C, with a high-soot, engine-tested oil at 200{degrees}C and with no lubrication at 200{degrees}C. For lowest wear under boundary lubricated conditions, the most promising candidates to emerge from this study were high velocity oxy-fuel (HVOF) Cr{sub 3} C{sub 2} - 20% NiCr and WC - 12% Co cermets, low temperature arc vapor deposited (LTAVD) CrN and plasma sprayed chromium oxides. Also,plasma sprayed Cr{sub 2}O{sub 3} and A1{sub 2}O{sub 3}-ZrO{sub 2} materials were found to give excellent wear resistance in unlubricated tests and at extremely high temperatures (450{degrees}C) with a syntheticoil. All of these materials would offer substantial wear reductions compared to the conventional electroplated hard chromium ring facing and thermally sprayed metallic coatings, especially at high temperatures and with high-soot oils subjected to degradation in diesel environments. The LTAVD CrN coating provided the lowest lubricated wear rates of all the materials evaluated, but may be too thin (4 {mu}m) for use as a top ring facing. Most of the coatings evaluated showed higher wear rates with high-soot, engine-tested oil than with fresh oil, with increases of more than a factor of ten in some cases. Generally, metallic materials were found to be much more sensitive to soot/oil degradation than ceramic and cermet coatings. Thus, decreased ``soot sensitivity`` is a significant driving force for utilizing ceramic or cermet coatings in diesel engine wear applications.

  16. Multiaxial deformation and life prediction model and experimental data for advanced silicon nitride ceramics

    SciTech Connect

    Ding, J.L.; Liu, K.C.; Brinkman, C.R.

    1993-06-01

    This paper summarizes recent experimental results on creep and creep rupture behavior of a commercial grade of Si{sub 3}N{sub 4} ceramic in the temperature range of 1150 to 1300C obtained at ORNL; and introduces a tentative multiaxial deformation and life prediction model for ceramic materials under general thermomechanical loadings. Issues related to the possible standardization of the data analysis methodology and possible future research needs for high temperature structural ceramics in the area of development of data base and life prediction methodology are also discussed.

  17. Elevated-Temperature "Ultra" Fast Fracture Strength of Advanced Ceramics: An Approach to Elevated-Temperature "Inert" Strength

    NASA Technical Reports Server (NTRS)

    Choi, S. R.; Gyekenyesi, J. P.

    1999-01-01

    The determination of "ultra" fast fracture strengths of five silicon nitride ceramics at elevated temperatures has been made by using constant stress-rate ("dynamic fatigue") testing with a series of "ultra" fast test rates. The test material included four monolithic and one SiC whisker-reinforced composite silicon nitrides. Of the five test materials, four silicon nitrides exhibited the elevated -temperature strengths that approaches their respective room-temperature strengths at an "ultra" fast test rate of 3.3 x 10(exp 4) MPa/s. This implies that slow cracks growth responsible for elevated-temperature failure can be eliminated or minimized by using the "ultra" fast test rate. These ongoing experimental results have shed light on laying a theoretical and practical foundation on the concept and definition of elevated-temperature "inert" strength behavior of advanced ceramics.

  18. In-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

    SciTech Connect

    Piscotty, M.A.; Davis, P.J.; Saito, T.T.; Blaedel, K.L.; Griffith, L.

    1997-08-01

    The demand and use of precision grinding of structural ceramics continue to increase as the worldwide advanced ceramic industry surpasses $20 billion is sales. Included in this industry are engineering structural ceramics, electronic ceramics, bioceramics and others. These materials are used in applications such as engine components, casting and extrusion dies, bearings, medical implants, nozzles, thermal insulators, and more. Along with the variety of ceramic applications comes a broad range of precision requirements, which in turn leads to various required processes to accommodate a spectrum of specifications. A process for grinding ceramic components to micrometer tolerances was employed and further developed at Lawrence Livermore National Laboratory for two separate grinding projects.

  19. Annual Conference on Composites and Advanced Ceramic Materials, 9th, Cocoa Beach, FL, January 20-23, 1985, Proceedings

    SciTech Connect

    Not Available

    1985-08-01

    The present conference discusses testing methods for ceramic matrix composites, developments in ceramic fibers, space transportation systems thermal protection materials, ceramics for heat engines and other severe environments, thermal sprayed coatings, the development status of ceramic tribology, and the fabrication of ceramics and hard metals. Specific attention is given to the mechanical characterization of ceramic and glass matrix composites, the application of fracture mechanics to fiber composites, the degradation properties of Nicalon SiC fibers, ceramic matrix toughening, SiC/glass composite phases, ceramic composite manufacture by infiltration, and ceramic coatings for the Space Shuttle's surface insulation. Also treated are design principles for anisotropic brittle materials, ceramics for intense radiant heat applications, ceramic-coated tip seals for turbojet engines, composite production by low pressure plasma deposition, tribology in military systems, lubrication for ceramics, a systems approach to the grinding of structural ceramics, and the fabrication of inorganic foams by microwave irradiation.

  20. Materials and Component Development for Advanced Turbine Systems

    SciTech Connect

    Alvin, M.A.; Pettit, F.; Meier, G.; Yanar, N.; Chyu, M.; Mazzotta, D.; Slaughter, W.; Karaivanov, V.; Kang, B.; Feng, C.; Chen, R.; Fu, T-C.

    2008-10-01

    In order to meet the 2010-2020 DOE Fossil Energy goals for Advanced Power Systems, future oxy-fuel and hydrogen-fired turbines will need to be operated at higher temperatures for extended periods of time, in environments that contain substantially higher moisture concentrations in comparison to current commercial natural gas-fired turbines. Development of modified or advanced material systems, combined with aerothermal concepts are currently being addressed in order to achieve successful operation of these land-based engines. To support the advanced turbine technology development, the National Energy Technology Laboratory (NETL) has initiated a research program effort in collaboration with the University of Pittsburgh (UPitt), and West Virginia University (WVU), working in conjunction with commercial material and coating suppliers as Howmet International and Coatings for Industry (CFI), and test facilities as Westinghouse Plasma Corporation (WPC) and Praxair, to develop advanced material and aerothermal technologies for use in future oxy-fuel and hydrogen-fired turbine applications. Our program efforts and recent results are presented.

  1. Development of Cost-Effective Low-Permeability Ceramic and Refractory Components for Aluminum Melting and Casting

    SciTech Connect

    Dale E. Brown; Puja B. Kadolkar

    2005-12-15

    The primary goal of this project was to develop and validate new classes of cost-effective low-permeability ceramic and refractory components for handling molten aluminum in both melting and casting environments. Three approaches were employed with partial to full success to achieve this goal: (1) Develop materials and methods for sealing surface porosity in thermal-shock-resistant ceramic refractories; (2) Develop new ceramic coatings for extreme service in molten aluminum operations, with particular emphasis on coatings based on highly stable oxide phases; and (3) Develop new monolithic refractories designed for lower-permeability applications using controlled porosity gradients and particle size distributions. The results of the research work and the field tests performed utilizing these three approaches are listed below: (1) It was demonstrated that high-density IR heating could be a tool for altering and sealing the surface porosity of fused silica. However, the process was not very cost-effective. (2) A low-cost glaze composition having a coefficient of thermal expansion (CTE) similar to that of a DFS tube was identified and was successfully tested for its integrity and adherence to DFS. Although the glaze acted as a barrier between the molten aluminum and the DFS, persistent porosity and crazing within the glaze affected its performance during the reactivity tests, thus acting as an obstacle in scaling up production of this glaze. (3) Pyrotek's XL glaze showed great success in improving the life of the DFS tubes. Pyrotek has reported an increasing market demand for the XL-coated DFS tubes, which exhibit useful lifetimes three times better than those of uncoated tubes. (4) A computer model to optimize particle size distribution for reduced permeability was developed and successfully applied to casting formulations. Silica riser tubes produced using these new formulations have been tested in a commercial aluminum casting facility and have been reported to

  2. ATTAP/AGT101 - Year 2 progress in ceramic technology development

    NASA Technical Reports Server (NTRS)

    Kidwell, J. R.; Lindberg, L. J.; Morey, R. E.

    1990-01-01

    The progress made by the Advanced Turbine Technology Applications Project (ATTAP) is summarized, with emphasis on the following areas: ceramic materials assessment and characterization, ceramic impact damage assessment, ceramic combustor evaluation, turbine inlet particle separator development, impact-tolerant turbine designs, and net-shape ceramic component fabrications. In the evolutionary ceramics development in the Automotive Gas Turbine (AGT101) and ATTAP programs initial designs were conceived to reduce stresses by using well-established criteria: bodies of revolution were preferred over nonaxisymmetric geometries, sharp corners were avoided, the contact area between components was kept as large as possible, and small parts were preferred over large when feasible. Projects discussed include: initial ceramic component fabrication by ceramic suppliers in 1990, engine test to 1371 C in 1991, 100-hr test bed engine durability test in 1991, and 300-hr test bed engine durability in 1992.

  3. Recent developments in glass-ceramic materials

    SciTech Connect

    Beall, G.H.

    1993-12-31

    Glass-ceramic materials can be made by sintering and crystallization of fine glass powders or by internal nucleation and crystallization of formed glass articles. In both cases, the final properties are controlled by phase assemblage and microstructure. Transparent glass-ceramics based upon ultra-fine grained {beta}-quartz solid solution have been developed with near-zero thermal expansion coefficient for a variety of consumer and technical products: cookware, stove-tops, telescope mirrors, optical gyroscopes. Fluormica glass-ceramics with a {open_quotes}house-of-cards{close_quotes} microstructure are easily machined and have found wide application in vacuum systems, precision dielectric components, insulators, and medical and dental prostheses. Acicular chain silicate glass-ceramics are strong and tough, and have recently been developed as high performance tableware and magnetic memory disk substrates. Sintered glass-ceramics based on magnesium aluminosilicate frits are the basis of copper-cordierite packaging for advanced IC packaging.

  4. Center for Technology for Advanced Scientific Component Software

    SciTech Connect

    Sottile, Matthew

    2010-06-30

    The UO portion of the larger TASCS project was focused on the usability subproject identified in the original project proposal. The key usability issue that we tacked was that of supporting legacy code developers in migrating to a component-oriented design pattern and development model with minimal manual labor. It was observed during the lifetime of the TASCS (and previous CCA efforts) that more often than not, users would arrive with existing code that was developed previous to their exposure to component design methods. As such, they were faced with the task of both learning the CCA toolchain and at the same time, manually deconstructing and reassembling their existing code to fit the design constraints imposed by components. This was a common complaint (and occasional reason for a user to abandon components altogether), so our task was to remove this manual labor as much as possible to lessen the burden placed on the end-user when adopting components for existing codes. To accomplish this, we created a source-based static analysis tool that used code annotations to drive code generation and transformation operations. The use of code annotations is due to one of the key technical challenges facing this work programming languages are limited in the degree to which application-specific semantics can be represented in code. For example, data types are often ambiguous. The C pointer is the most common example cited in practice. Given a pointer to a location in memory, should it be interpreted as a singleton or an array. If it is to be interpreted as an array, how many dimensions does the array have? What are their extents? The annotation language that we designed and implemented addresses this ambiguity issue by allowing users to decorate their code in places where ambiguity exists in order to guide tools to interpret what the programmer really intends.

  5. Center for Technology for Advanced Scientific Component Software (TASCS)

    SciTech Connect

    Dr. Mathew Sottile

    2010-06-30

    The UO portion of the larger TASCS project was focused on the usability subproject identified in the original project proposal. The key usability issue that we tacked was that of supporting legacy code developers in migrating to a component-oriented design pattern and development model with minimal manual labor. It was observed during the lifetime of the TASCS (and previous CCA efforts) that more often than not, users would arrive with existing code that was developed previous to their exposure to component design methods. As such, they were faced with the task of both learning the CCA toolchain and at the same time, manually deconstructing and reassembling their existing code to fit the design constraints imposed by components. This was a common complaint (and occasional reason for a user to abandon components altogether), so our task was to remove this manual labor as much as possible to lessen the burden placed on the end-user when adopting components for existing codes. To accomplish this, we created a source-based static analysis tool that used code annotations to drive code generation and transformation operations. The use of code annotations is due to one of the key technical challenges facing this work | programming languages are limited in the degree to which application-specific semantics can be represented in code. For example, data types are often ambiguous. The C pointer is the most common example cited in practice. Given a pointer to a location in memory, should it be interpreted as a singleton or an array. If it is to be interpreted as an array, how many dimensions does the array have? What are their extents? The annotation language that we designed and implemented addresses this ambiguity issue by allowing users to decorate their code in places where ambiguity exists in order to guide tools to interpret what the programmer really intends.

  6. Component-Level Prognostics Health Management Framework for Passive Components - Advanced Reactor Technology Milestone: M2AT-15PN2301043

    SciTech Connect

    Ramuhalli, Pradeep; Roy, Surajit; Hirt, Evelyn H.; Prowant, Matthew S.; Pitman, Stan G.; Tucker, Joseph C.; Dib, Gerges; Pardini, Allan F.

    2015-06-19

    This report describes research results to date in support of the integration and demonstration of diagnostics technologies for prototypical advanced reactor passive components (to establish condition indices for monitoring) with model-based prognostics methods. Achieving this objective will necessitate addressing several of the research gaps and technical needs described in previous technical reports in this series.

  7. Materials and Component Development for Advanced Turbine Systems

    SciTech Connect

    Alvin, M A; Pettit, F; Meier, G H; Yanar, M; Helminiak, M; Chyu, M; Siw, S; Slaughter, W S; Karaivanov, V; Kang, B S; Feng, C; Tannebaum, J M; Chen, R; Zhang, B; Fu, T; Richards, G A; Sidwell, T G; Straub, D; Casleton, K H; Dogan, O M

    2008-07-01

    Hydrogen-fired and oxy-fueled land-based gas turbines currently target inlet operating temperatures of ~1425-1760°C (~2600-3200°F). In view of natural gas or syngas-fired engines, advancements in both materials, as well as aerothermal cooling configurations are anticipated prior to commercial operation. This paper reviews recent technical accomplishments resulting from NETL’s collaborative research efforts with the University of Pittsburgh and West Virginia University for future land-based gas turbine applications.

  8. Development of improved coating for advanced carbon-carbon components

    NASA Technical Reports Server (NTRS)

    Yamaki, Y. R.; Brown, J. J.

    1984-01-01

    Reaction sintered silicon nitride (RSSN) was studied as a substitute coating material on the carbon-carbon material (RCC) presently used as a heat shield on the space shuttle, and on advanced carbon-carbon (ACC), a later development. On RCC, RSSN showed potential in a 538 C (1000 F) screening test in which silicon carbide coated material exhibits its highest oxidation rate; RSSN afforded less protection to ACC because of a larger thermal expansion mismatch. Organosilicon densification and metallic silicon sealing methods were studied as means of further increasing the oxidation resistance of the coating, and some improvement was noted when these methods were employed.

  9. Methods of Si based ceramic components volatilization control in a gas turbine engine

    SciTech Connect

    Garcia-Crespo, Andres Jose; Delvaux, John; Dion Ouellet, Noemie

    2016-09-06

    A method of controlling volatilization of silicon based components in a gas turbine engine includes measuring, estimating and/or predicting a variable related to operation of the gas turbine engine; correlating the variable to determine an amount of silicon to control volatilization of the silicon based components in the gas turbine engine; and injecting silicon into the gas turbine engine to control volatilization of the silicon based components. A gas turbine with a compressor, combustion system, turbine section and silicon injection system may be controlled by a controller that implements the control method.

  10. How the Common Component Architecture Advances Compuational Science

    SciTech Connect

    Kumfert, G; Bernholdt, D; Epperly, T; Kohl, J; McInnes, L C; Parker, S; Ray, J

    2006-06-19

    Computational chemists are using Common Component Architecture (CCA) technology to increase the parallel scalability of their application ten-fold. Combustion researchers are publishing science faster because the CCA manages software complexity for them. Both the solver and meshing communities in SciDAC are converging on community interface standards as a direct response to the novel level of interoperability that CCA presents. Yet, there is much more to do before component technology becomes mainstream computational science. This paper highlights the impact that the CCA has made on scientific applications, conveys some lessons learned from five years of the SciDAC program, and previews where applications could go with the additional capabilities that the CCA has planned for SciDAC 2.

  11. Scalable Advanced Network Services Based on Coordinated Active Components

    DTIC Science & Technology

    2004-02-01

    as a means of customizing both high functionality and scalable communication components to meet the needs of specific services. • A service...considering both the service quality for the user and the efficient use of the infrastructure (cost). ( 4 ) Finally, the synthesizer needs to configure the...response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed , and completing

  12. Recent advances in component resolved diagnosis in food allergy.

    PubMed

    Borres, Magnus P; Maruyama, Nobuyuki; Sato, Sakura; Ebisawa, Motohiro

    2016-10-01

    Due to the high prevalence of food allergic diseases globally there are increasing demands in clinical practice for managing IgE-mediated conditions. During the last decade, component resolved diagnostics has been introduced into the field of clinical allergology, providing information that cannot be obtained from extract-based tests. Component resolved data facilitate more precise diagnosis of allergic diseases and identify sensitizations attributable to cross-reactivity. Furthermore it assists risk assessment in clinical practice as sensitization to some allergenic molecules is related to persistence of clinical symptoms and systemic rather than local reactions. The information may also aid the clinician in prescription of oral immunotherapy (OIT) in patients with severe symptoms, and in giving advice on food allergen avoidance or on the need to perform food challenges. The use of allergen components is rapidly evolving and increases our possibility to treat food allergic patients with a more individual approach. Using molecular allergology, we can already now better diagnose, prognose and grade the food allergy. In summary, daily routine molecular allergy diagnostics offers a number of benefits that give us a higher diagnostic precision and allow for better management of the patient.

  13. NASA/CARES dual-use ceramic technology spinoff applications

    NASA Technical Reports Server (NTRS)

    Powers, Lynn M.; Janosik, Lesley A.; Gyekenyesi, John P.; Nemeth, Noel N.

    1994-01-01

    NASA has developed software that enables American industry to establish the reliability and life of ceramic structures in a wide variety of 21st Century applications. Designing ceramic components to survive at higher temperatures than the capability of most metals and in severe loading environments involves the disciplines of statistics and fracture mechanics. Successful application of advanced ceramics material properties and the use of a probabilistic brittle material design methodology. The NASA program, known as CARES (Ceramics Analysis and Reliability Evaluation of Structures), is a comprehensive general purpose design tool that predicts the probability of failure of a ceramic component as a function of its time in service. The latest version of this software, CARESALIFE, is coupled to several commercially available finite element analysis programs (ANSYS, MSC/NASTRAN, ABAQUS, COSMOS/N4, MARC), resulting in an advanced integrated design tool which is adapted to the computing environment of the user. The NASA-developed CARES software has been successfully used by industrial, government, and academic organizations to design and optimize ceramic components for many demanding applications. Industrial sectors impacted by this program include aerospace, automotive, electronic, medical, and energy applications. Dual-use applications include engine components, graphite and ceramic high temperature valves, TV picture tubes, ceramic bearings, electronic chips, glass building panels, infrared windows, radiant heater tubes, heat exchangers, and artificial hips, knee caps, and teeth.

  14. A review of advanced metallic and ceramic materials suitable for high temperature use in space structures

    NASA Astrophysics Data System (ADS)

    Bashford, David

    Spacecraft, satellites and launch vehicles require efficient, lightweight structural materials. At present, the structural requirements can be largely met by aluminium alloys and polymeric matrix composites based on carbon fibres. However, increasingly there will be a need to specify materials capable of sustaining operational use at temperatures in excess of 250°C and towards 2000°C. Ambitious spaceplane projects such as Hermes, HOTOL, Sanger, HOPE and NASP have highlighted this need. Within the operational temperature band 250°C to 2000°C various metallic and ceramic materials are appropriate for consideration, either in alloy or composite form. This review paper identifies the status of technology on the following: i) Aluminium and titanium alloys and their composites. ii) Superalloys and their composites. iii) Carbon, glass-ceramic and ceramic matrix composites. The development of more weight efficient and thermally stable metallic and ceramic materials has centred on a number of key areas (1). For metallics, improved alloy composition and grain refinement from Rapidly Solidified Powders have given improvements in strength retention at high temperatures (a). The introduction of reinforcements, either particulate, whisker or continuous fibre, have improved the basic alloys by reducing density, increasing stiffness and strength and extending thermal capabilities. Monolithic ceramics possess thermal stability but are inherently brittle and crack sensitive. The addition of ceramic fibres and whiskers has the effect of modifying fracture characteristics by introducing "pseudo-ductility" to raise apparent toughness. In the foreseeable future the emerging high temperature materials will find uses in: Spaceplane substructures and control surfaces; Thermal protection systems and insulation; Propulsion plants and thruster units; Air breathing engines.

  15. Structural Dynamics Testing of Advanced Stirling Convertor Components

    NASA Technical Reports Server (NTRS)

    Oriti, Sal; Williams, Zach

    2013-01-01

    NASA Glenn Research Center has been supporting the development of Stirling energy conversion for use in space. Lockheed Martin has been contracted by the Department of Energy to design and fabricate flight-unit Advanced Stirling Radioisotope Generators, which utilize Sunpower, Inc., free-piston Advanced Stirling Convertors. The engineering unit generator has demonstrated conversion efficiency in excess of 20 percent, offering a significant improvement over existing radioisotope-fueled power systems. NASA Glenn has been supporting the development of this generator by developing the convertors through a technology development contract with Sunpower, and conducting research and experiments in a multitude of areas, such as high-temperature material properties, organics testing, and convertor-level extended operation. Since the generator must undergo launch, several launch simulation tests have also been performed at the convertor level. The standard test sequence for launch vibration exposure has consisted of workmanship and flight acceptance levels. Together, these exposures simulate what a flight convertor will experience. Recently, two supplementary tests were added to the launch vibration simulation activity. First was a vibration durability test of the convertor, intended to quantify the effect of vibration levels up to qualification level in both the lateral and axial directions. Second was qualification-level vibration of several heater heads with small oxide inclusions in the material. The goal of this test was to ascertain the effect of the inclusions on launch survivability to determine if the heater heads were suitable for flight.

  16. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    Prof. Stratis V. Sotirchos

    2001-02-01

    The main objective of this research project was the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Since alumina has excellent resistance to corrosion but coefficient than silicon carbide, the key idea of this project has been to develop graded coatings with composition varying smoothly along their thickness between an inner (base) layer of mullite in contact with the silicon carbide component and an outer layer of pure alumina, which would function as the actual protective coating of the component. (Mullite presents very good adhesion towards silicon carbide and has thermal expansion coefficient very close to that of the latter.)

  17. Recent advances in understanding the reinforcing ability and mechanism of carbon nanotubes in ceramic matrix composites.

    PubMed

    Estili, Mehdi; Sakka, Yoshio

    2014-12-01

    Since the discovery of carbon nanotubes (CNTs), commonly referred to as ultimate reinforcement, the main purpose for fabricating CNT-ceramic matrix composites has been mainly to improve the fracture toughness and strength of the ceramic matrix materials. However, there have been many studies reporting marginal improvements or even the degradation of mechanical properties. On the other hand, those studies claiming noticeable toughening measured using indentation, which is an indirect/unreliable characterization method, have not demonstrated the responsible mechanisms applicable to the nanoscale, flexible CNTs; instead, those studies proposed those classical methods applicable to microscale fiber/whisker reinforced ceramics without showing any convincing evidence of load transfer to the CNTs. Therefore, the ability of CNTs to directly improve the macroscopic mechanical properties of structural ceramics has been strongly questioned and debated in the last ten years. In order to properly discuss the reinforcing ability (and possible mechanisms) of CNTs in a ceramic host material, there are three fundamental questions to our knowledge at both the nanoscale and macroscale levels that need to be addressed: (1) does the intrinsic load-bearing ability of CNTs change when embedded in a ceramic host matrix?; (2) when there is an intimate atomic-level interface without any chemical reaction with the matrix, could one expect any load transfer to the CNTs along with effective load bearing by them during crack propagation?; and (3) considering their nanometer-scale dimensions, flexibility and radial softness, are the CNTs able to improve the mechanical properties of the host ceramic matrix at the macroscale when individually, intimately and uniformly dispersed? If so, how? Also, what is the effect of CNT concentration in such a defect-free composite system? Here, we briefly review the recent studies addressing the above fundamental questions. In particular, we discuss the new

  18. Recent advances in understanding the reinforcing ability and mechanism of carbon nanotubes in ceramic matrix composites

    NASA Astrophysics Data System (ADS)

    Estili, Mehdi; Sakka, Yoshio

    2014-12-01

    Since the discovery of carbon nanotubes (CNTs), commonly referred to as ultimate reinforcement, the main purpose for fabricating CNT-ceramic matrix composites has been mainly to improve the fracture toughness and strength of the ceramic matrix materials. However, there have been many studies reporting marginal improvements or even the degradation of mechanical properties. On the other hand, those studies claiming noticeable toughening measured using indentation, which is an indirect/unreliable characterization method, have not demonstrated the responsible mechanisms applicable to the nanoscale, flexible CNTs; instead, those studies proposed those classical methods applicable to microscale fiber/whisker reinforced ceramics without showing any convincing evidence of load transfer to the CNTs. Therefore, the ability of CNTs to directly improve the macroscopic mechanical properties of structural ceramics has been strongly questioned and debated in the last ten years. In order to properly discuss the reinforcing ability (and possible mechanisms) of CNTs in a ceramic host material, there are three fundamental questions to our knowledge at both the nanoscale and macroscale levels that need to be addressed: (1) does the intrinsic load-bearing ability of CNTs change when embedded in a ceramic host matrix?; (2) when there is an intimate atomic-level interface without any chemical reaction with the matrix, could one expect any load transfer to the CNTs along with effective load bearing by them during crack propagation?; and (3) considering their nanometer-scale dimensions, flexibility and radial softness, are the CNTs able to improve the mechanical properties of the host ceramic matrix at the macroscale when individually, intimately and uniformly dispersed? If so, how? Also, what is the effect of CNT concentration in such a defect-free composite system? Here, we briefly review the recent studies addressing the above fundamental questions. In particular, we discuss the new

  19. Recent advances in understanding the reinforcing ability and mechanism of carbon nanotubes in ceramic matrix composites

    PubMed Central

    Estili, Mehdi; Sakka, Yoshio

    2014-01-01

    Since the discovery of carbon nanotubes (CNTs), commonly referred to as ultimate reinforcement, the main purpose for fabricating CNT–ceramic matrix composites has been mainly to improve the fracture toughness and strength of the ceramic matrix materials. However, there have been many studies reporting marginal improvements or even the degradation of mechanical properties. On the other hand, those studies claiming noticeable toughening measured using indentation, which is an indirect/unreliable characterization method, have not demonstrated the responsible mechanisms applicable to the nanoscale, flexible CNTs; instead, those studies proposed those classical methods applicable to microscale fiber/whisker reinforced ceramics without showing any convincing evidence of load transfer to the CNTs. Therefore, the ability of CNTs to directly improve the macroscopic mechanical properties of structural ceramics has been strongly questioned and debated in the last ten years. In order to properly discuss the reinforcing ability (and possible mechanisms) of CNTs in a ceramic host material, there are three fundamental questions to our knowledge at both the nanoscale and macroscale levels that need to be addressed: (1) does the intrinsic load-bearing ability of CNTs change when embedded in a ceramic host matrix?; (2) when there is an intimate atomic-level interface without any chemical reaction with the matrix, could one expect any load transfer to the CNTs along with effective load bearing by them during crack propagation?; and (3) considering their nanometer-scale dimensions, flexibility and radial softness, are the CNTs able to improve the mechanical properties of the host ceramic matrix at the macroscale when individually, intimately and uniformly dispersed? If so, how? Also, what is the effect of CNT concentration in such a defect-free composite system? Here, we briefly review the recent studies addressing the above fundamental questions. In particular, we discuss the new

  20. Silicon-Based Ceramic-Matrix Composites for Advanced Turbine Engines: Some Degradation Issues

    NASA Technical Reports Server (NTRS)

    Thomas-Ogbuji, Linus U. J.

    2000-01-01

    SiC/BN/SiC composites are designed to take advantage of the high specific strengths and moduli of non-oxide ceramics, and their excellent resistance to creep, chemical attack, and oxidation, while circumventing the brittleness inherent in ceramics. Hence, these composites have the potential to take turbine engines of the future to higher operating temperatures than is achievable with metal alloys. However, these composites remain developmental and more work needs to be done to optimize processing techniques. This paper highlights the lingering issue of pest degradation in these materials and shows that it results from vestiges of processing steps and can thus be minimized or eliminated.

  1. NASA's Advanced Environmental Barrier Coatings Development for SiC/SiC Ceramic Matrix Composites: Understanding Calcium Magnesium Alumino-Silicate (CMAS) Degradations and Resistance

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming

    2014-01-01

    Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is essential to the viability and reliability of the envisioned CMC engine component applications, ensuring integrated EBC-CMC system durability and designs are achievable for successful applications of the game-changing component technologies and lifing methodologies.This paper will emphasize recent NASA environmental barrier coating developments for SiCSiC turbine airfoil components, utilizing advanced coating compositions, state-of-the-art processing methods, and combined mechanical and environment testing and durability evaluations. The coating-CMC degradations in the engine fatigue-creep and operating environments are particularly complex; one of the important coating development aspects is to better understand engine environmental interactions and coating life debits, and we have particularly addressed the effect of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the durability of the environmental barrier coating systems, and how the temperature capability, stability and cyclic life of the candidate rare earth oxide and silicate coating systems will be impacted in the presence of the CMAS at high temperatures and under simulated heat flux conditions. Advanced environmental barrier coating systems, including HfO2-Si with rare earth dopant based bond coat systems, will be discussed for the performance improvements to achieve better temperature capability and CMAS resistance for future engine operating conditions.

  2. Ceramic material suitable for repair of a space vehicle component in a microgravity and vacuum environment, method of making same, and method of repairing a space vehicle component

    NASA Technical Reports Server (NTRS)

    Riedell, James A. (Inventor); Easler, Timothy E. (Inventor)

    2009-01-01

    A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium diboride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

  3. High temperature corrosion of advanced ceramic materials for hot gas filters and heat exchangers

    SciTech Connect

    Crossland, C.E.; Shelleman, D.L.; Spear, K.E.

    1996-08-01

    A vertical flow-through furnace has been built to study the effect of corrosion on the morphology and mechanical properties of ceramic hot gas filters. Sections of 3M Type 203 and DuPont Lanxide SiC-SiC filter tubes were sealed at one end and suspended in the furnace while being subjected to a simulated coal combustion environment at 870{degrees}C. X-ray diffraction and electron microscopy is used to identify phase and morphology changes due to corrosion while burst testing determines the loss of mechanical strength after exposure to the combustion gases. Additionally, a thermodynamic database of gaseous silicon compounds is currently being established so that calculations can be made to predict important products of the reaction of the environment with the ceramics. These thermodynamic calculations provide useful information concerning the regimes where the ceramic may be degraded by material vaporization. To verify the durability and predict lifetime performance of ceramic heat exchangers in coal combustion environments, long-term exposure testing of stressed (internally pressurized) tubes must be performed in actual coal combustion environments. The authors have designed a system that will internally pressurize 2 inch OD by 48 inch long ceramic heat exchanger tubes to a maximum pressure of 200 psi while exposing the outer surface of the tubes to coal combustion gas at the Combustion and Environmental Research Facility (CERF) at the Pittsburgh Energy and Technology Center. Water-cooled, internal o-ring pressure seals were designed to accommodate the existing 6 inch by 6 inch access panels of the CERF. Tubes will be exposed for up to a maximum of 500 hours at temperatures of 2500 and 2600{degrees}F with an internal pressure of 200 psi. If the tubes survive, their retained strength will be measured using the high temperature tube burst test facility at Penn State University. Fractographic analysis will be performed to identify the failure source(s) for the tubes.

  4. Effect of advanced component technology on helicopter transmissions

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Townsend, Dennis P.

    1989-01-01

    Experimental tests were performed on the NASA/Bell Helicopter Textron (BHT) 500 hp advanced technology transmission (ATT) at the NASA Lewis Research Center. The ATT was a retrofit of the OH-58C helicopter 236 kW (317 hp) main rotor transmission, upgraded to 373 kW (500 hp), with a design goal of retaining long life with a minimum increase in cost, weight, and size. Vibration, strain, efficiency, deflection, and temperature experiments were performed and the results were compared to previous experiments on the OH-58A, OH-58C, and UH-60A transmissions. The high-contact-ratio gears and the cantilevered-mounted, flexible ring gear of the ATT reduced vibration compared to that of the OH-58C. The ATT flexible ring gear improved planetary load sharing compared to that of the rigid ring gear of the UH-60A transmission. The ATT mechanical efficiency was lower than that of the OH-58A transmission, probably due to the high-contact-ratio planetary gears.

  5. Heat pipe radiation cooling of advanced hypersonic propulsion system components

    NASA Technical Reports Server (NTRS)

    Martin, R. A.; Keddy, M.; Merrigan, M. A.; Silverstein, C. C.

    1991-01-01

    Heat transfer, heat pipe, and system studies were performed to assess the newly proposed heat pipe radiation cooling (HPRC) concept. With an HPRC system, heat is removed from the ramburner and nozzle of a hypersonic aircraft engine by a surrounding, high-temperature, heat pipe nacelle structure, transported to nearby external surfaces, and rejected to the environment by thermal radiation. With HPRC, the Mach number range available for using hydrocarbon fuels for aircraft operation extends into the Mach 4 to Mach 6 range, up from the current limit of about Mach 4. Heat transfer studies using a newly developed HPRC computer code determine cooling system and ramburner and nozzle temperatures, heat loads, and weights for a representative combined-cycle engine cruising at Mach 5 at 80,000 ft altitude. Heat pipe heat transport calculations, using the Los Alamos code HTPIPE, reveal that adequate heat trasport capability is available using molybdenum-lithium heat pipe technology. Results show that the HPRC system radiator area is limited in size to the ramburner-nozzle region of the engine nacelle; reasonable system weights are expected; hot section temperatures are consistent with advanced structural materials development goals; and system impact on engine performance is minimal.

  6. Silicon Nitride and Silicon Carbide Ceramics Structural Components in Avionics and Space

    NASA Astrophysics Data System (ADS)

    Berroth, Karl

    2014-06-01

    In the paper, Silicon Nitride and silicon carbide components for avionics and space are described. These lightweight stiff and strong materials with low and very low CTE and high thermal conductivity provide means for new designs and higher resolution in passive structures for optical instruments. Material properties and application examples are discussed.

  7. Development of ceramic matrix composites for application in the ceramic technology for advanced heat engines project. Final report, Phase 2

    SciTech Connect

    Yeh, H.; Solidum, E.; Karasek, K.; Stranford, G.; Yuhas, D.; Schienle, J.; Bradley, S.

    1992-04-01

    The objective of this effort (Phase II of a multi-phase program) was to maximize the toughness of a high-temperature Si{sub 3}N{sub 4} (GN-10) by the near-net-shape fabrication technology established previously (Phase I). Acid-etched American Matrix SiC whiskers were selected as the reinforcement. Extensive green forming and densification process optimizations were conducted. The results showed that whisker addition increased the toughness slightly, but decreased the strength of the material. It has been recommended to discontinue the whisker reinforcement approach, and to instead pursue the in-situ grown-whisker reinforcement approach. To address future needs for the composite technology, two supplemental efforts were conducted using monolithic GN-10 Si{sub 3}N{sub 4}. These were nanometer deposition of sintering aids and ultrasonic characterization of drying. Spray drying, polymerization, basic precipitation, and evaporation yielded more uniform sintering aid distributions than conventional ball milling. Spray drying was selected for scale-up study. Improved mechanical properties were demonstrated. The results of the ultrasonic study showed that variations in ultrasonic compressional velocity in slip-cast components are more complex than anticipated. Specifically, it was found that the sonic velocity, as a function of moisture content, was double-valued. This behavior, together with the problems associated with maintaining uniform couplant, precludes the use of ultrasonics as a routine means of monitoring moisture content.

  8. Spectroscopic features of copper ions in multi-component Na2Osbnd PbOsbnd Bi2O3sbnd SiO2 glass ceramics

    NASA Astrophysics Data System (ADS)

    Sambasiva Rao, M. V.; Suresh, S.; Narendrudu, T.; Suneel Kumar, A.; Chinna Ram, G.; Krishna Rao, D.

    2016-12-01

    Multi-component Na2Osbnd PbOsbnd Bi2O3sbnd SiO2 glasses were crystallised with different CuO contents (0-1 mol % in steps of 0.2) as nucleating agent. These glass ceramics were characterized by XRD, SEM and DTA techniques and indicated the samples contain well defined and randomly distributed grains of different crystalline phases. Spectroscopic studies viz., optical absorption, EPR, FTIR and Raman were also carried out on these glass ceramics. The broad absorption band observed in the wavelength region 550-1000 nm in these glass ceramics and is the characteristic of Cu2+ ions. Optical absorption and EPR studies suggest that Cu2+ ions enter into the lattice as tetragonally distorted octahedral symmetry for which the bonding parameters were evaluated. FTIR and Raman spectra give important information about the nature of various structural units in the glass ceramic matrix. The analysis of these spectroscopic investigations reveals that with increase in the concentration of nucleating agent CuO, copper ions exist in Cu2+ state they act as modifiers and increases the degree of disorder in the glass ceramic network.

  9. National Center for Advanced Information Components Manufacturing. Program summary report, Volume II

    SciTech Connect

    1996-10-01

    The National Center for Advanced Information Components Manufacturing focused on manufacturing research and development for flat panel displays, advanced lithography, microelectronics, and optoelectronics. This report provides an overview of the program, program history, summaries of the technical projects, and key program accomplishments.

  10. IMPROVEMENT OF WEAR COMPONENT'S PERFORMANCE BY UTILIZING ADVANCED MATERIALS AND NEW MANUFACTURING TECHNOLOGIES: CASTCON PROCESS FOR MINING APPLICATIONS

    SciTech Connect

    Xiaodi Huang; Richard Gertsch

    2001-07-27

    A tungsten carbide monolithic preform was produced by Advanced Ceramics. MTU conducted various sintering tests on the preform to determine conditions for removing the organic binder and improving the mechanical properties. The originally selected parameters for sintering did not perform as anticipated and further testing is underway.

  11. Ceramic materials as bearing surfaces for total hip arthroplasty.

    PubMed

    D'Antonio, James A; Sutton, Kate

    2009-02-01

    During the past decade, advances in total hip arthroplasty component design have produced implants with reliable clinical results in regard to fixation. The foremost unresolved challenge has been the development of bearing surfaces that can withstand the higher demands of younger and more active patients. New alternative bearings with superior wear characteristics that minimize debris include ceramic-on-ceramic, metal-on-metal, and highly cross-linked polyethylenes in combination with ceramic or metal. Alumina-on-alumina ceramic bearings are extremely hard and scratch resistant and provide superior lubrication and wear resistance compared with other bearing surfaces in clinical use. Survivorship revision for any reason for the alumina ceramic bearings at 10 years was significantly higher compared with metal-on-polyethylene. Bearings currently being studied because of their encouraging wear performance in the laboratory are an alumina matrix (82% alumina, 17% zirconia, 0.3% chromium oxide), zirconium oxide, and ceramic-on-cobalt-chromium.

  12. 7 CFR 1032.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Class prices, component prices, and advanced pricing factors. 1032.50 Section 1032.50 Agriculture Regulations of the Department of Agriculture (Continued... CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.50 Class prices, component...

  13. 7 CFR 1032.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Class prices, component prices, and advanced pricing factors. 1032.50 Section 1032.50 Agriculture Regulations of the Department of Agriculture (Continued... CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.50 Class prices, component...

  14. 7 CFR 1032.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Class prices, component prices, and advanced pricing factors. 1032.50 Section 1032.50 Agriculture Regulations of the Department of Agriculture (Continued... CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.50 Class prices, component...

  15. 7 CFR 1032.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Class prices, component prices, and advanced pricing factors. 1032.50 Section 1032.50 Agriculture Regulations of the Department of Agriculture (Continued... CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.50 Class prices, component...

  16. 7 CFR 1032.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Class prices, component prices, and advanced pricing factors. 1032.50 Section 1032.50 Agriculture Regulations of the Department of Agriculture (Continued... CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.50 Class prices, component...

  17. Ceramic Femoral Components in Total Knee Arthroplasty - Two Year Follow-Up Results of an International Prospective Multi-Centre Study

    PubMed Central

    Bergschmidt, Philipp; Bader, Rainer; Ganzer, Dirk; Hauzeur, Christian; Lohmann, Christoph; Rüther, Wolfgang; Tigani, Domenico; Rani, Nicola; Prats, Fernando Lopez; Zorzi, Claudio; Madonna, Vincenzo; Rigotti, Stefano; Benazzo, Francesco; Rossi, Stefano Marco Paolo; Kundt, Guenther; Bloch, Hans Rudolf; Mittelmeier, Wolfram

    2012-01-01

    Background: Total knee arthroplasty can be considered as a reliable surgical procedure with a good long-term clinical result. However, implant failure due to particle induced aseptic loosening as well as the aspect of hypersensitivity to metal ions still remains an emerging issue. Methods: The purpose of this prospective international multi-centre study was to evaluate the clinical and radiological outcomes and the reliability of the unconstrained Multigen Plus Total Knee System with a new BIOLOX® delta ceramic femoral component. Cemented total knee arthroplasty was performed on 108 patients (110 knees) at seven hospitals in three countries. Clinical and radiological evaluations were performed preoperatively, and after 3, 12 and 24 months postoperatively using the HSS-, WOMAC-, SF-36-score and standardised X-rays. Results: The mean preoperative HSS-Score amounted to 55.5 ± 11.5 points and improved significantly in all postoperative evaluations (85.7 ± 11.7 points at 24 months). Furthermore, improvements in WOMAC- and SF-36-score were evaluated as significant at all points of evaluation. Radiolucent lines around the femoral ceramic component at 24 months were found in four cases. Progression of radiolucent lines was not seen and no implant loosening was observed. During the 24 month follow-up eight patients underwent subsequent surgery due to reasons unrelated to the implant material. Conclusions: The observed clinical and radiological results are encouraging for a long-term survival of the ceramic femoral component. Therefore, ceramic implants could be a promising solution not only for patients with allergies against metallic implant materials, but also for the osteoarthritic knee joint. Long-term follow-up is necessary to draw conclusions regarding the superiority of the ceramic knee implants concerning in vivo wear and long-term survivorship. PMID:22582104

  18. The Compressive Failure of Aluminum Nitride Considered as a Model Advanced Ceramic

    DTIC Science & Technology

    2012-06-01

    and fragmentation of hot-pressed silicon carbide under uniaxial compression. Acta Materialia 52 (2), 355–367. Xia, Q., Xia, H., Ruoff, A.L., 1993...Orphal et al., 1996) both as a standalone material and as part of ceramic composites (particularly with SiC ). Much of the literature on bulk...compression experiments. Tungsten carbide platens jacketed by the Ti-6Al-4V titanium alloy were used to protect the loading surfaces of the testing

  19. Ceramics for the advanced automotive gas turbine engine - A look at a single shaft design

    NASA Technical Reports Server (NTRS)

    Nosek, S. M.

    1978-01-01

    A single-shaft regenerative design with a single-stage radial turbine is analyzed in terms of achievable fuel economy for the cases of both limited and unlimited turbine tip speed and regenerator inlet temperature. The 100-hp engine for a 3500-lb automobile is designed to use gasoline. Fuel economy data and operating parameters are presented for different values of turbine inlet temperatures, and turbine stress estimates and ceramic design stress estimates are discussed.

  20. Advanced Surface Treatments and Adhesive Bonding Testing Schemes of Ceramic Assemblies

    DTIC Science & Technology

    2006-11-01

    2000]. Silane or other adhesion promoters coupled with structural adhesive formulations tailored for specific applications have vastly improved the...interactions of common adhesion promoters, such as silane coupling agents, have not been explored in the case of ceramic substrates. Performing an adhesive...cleaning procedures, silane coupling agent application, and surface drying. For surface cleaning, samples were degreased with an acetone rinse and grit

  1. High Temperature Advanced Structural Composites. Volume 2. Ceramic Matrix Composites, Fiber Processing and Properties, and Interfaces

    DTIC Science & Technology

    1993-04-02

    our computed properties of hot pressed aluminum nitride. Ceram. Int. 8 value is a few orders of magnitude lower than the 1 (1982) pp 34-40 observed one...prospect of alloying SiC with other covalencly bonded refractory materials, such as AlN, to achieve microstructural control or alter properties has...specialty applica- tions. In this review the processing, properties . and uses of the end-member compounds. silicon dioxide (SiO.) and aluminum oxide

  2. Development of wear resistant ceramic coatings for diesel engine components. Final report

    SciTech Connect

    Haselkorn, M.H.

    1992-04-01

    Improved fuel economy and a reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, insulating the combustion chamber components will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150{degree}C to over 300{degree}C. Existing ring/liner materials can not withstand these higher operating temperatures and for this reason, new materials need to be developed for this critical tribological interface. The overall goal of this program is the development of piston ring/cylinder liner material pairs which would be able to provide the required friction and wear properties at these more severe operating conditions. More specifically, this program first selected, and then evaluated, potential d/wear resistant coatings which could be applied to either piston rings an or cylinder liners and provide, at 350{degree}C under lubricated conditions, coefficients of friction below 0.1 and wear rates of less than 25 {times} lO{sup {minus}6} mm/hour. The processes selected for applying the candidate wear resistant coatings to piston rings and/or cylinder liners were plasma spraying, chemical vapor, physical vapor and low temperature arc vapor deposition techniques as well as enameling techniques.

  3. Advancement of Cellular Ceramics Made of Silicon Carbide for Burner Applications

    NASA Astrophysics Data System (ADS)

    Fuessel, Alexander; Klemm, Hagen; Boettge, Daniela; Marschallek, Felix; Adler, Joerg; Michaelis, Alexander

    2011-04-01

    Lower emissions of CO and NOx as well as a higher power density were observed in combustion processes performed in porous media like ceramic foams. Only a few materials are applicable for porous burners. Open-celled ceramic foams made of silicon carbide are of particular interest because of their outstanding properties. Two different SiC materials have been investigated, silicon-infiltrated silicon carbide (SiSiC) and pressureless sintered silicon carbide (SSiC). The oxidation behaviour of both has been characterized by furnace oxidation and burner tests up to 500 h operating time. Up to a temperature of 1200 °C SiSiC exhibited a good oxidation resistance in combustion gases by forming a protective layer of silica. High inner porosity up to 30% in the ceramic struts was found in the SSiC material. Caused by inner oxidation processes the pure material SSiC allows only short time applications with a temperature limit of 1550 °C in combustion gases. An increase of the lifetime of the SSiC foams was obtained by development of a new SSiC with an inner porosity of less than 12%. The result was a considerable reduction of the inner oxidation processes in the SSiC struts.

  4. SCARE: A post-processor program to MSC/NASTRAN for the reliability analysis of structural ceramic components

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, J. P.

    1985-01-01

    A computer program was developed for calculating the statistical fast fracture reliability and failure probability of ceramic components. The program includes the two-parameter Weibull material fracture strength distribution model, using the principle of independent action for polyaxial stress states and Batdorf's shear-sensitive as well as shear-insensitive crack theories, all for volume distributed flaws in macroscopically isotropic solids. Both penny-shaped cracks and Griffith cracks are included in the Batdorf shear-sensitive crack response calculations, using Griffith's maximum tensile stress or critical coplanar strain energy release rate criteria to predict mixed mode fracture. Weibull material parameters can also be calculated from modulus of rupture bar tests, using the least squares method with known specimen geometry and fracture data. The reliability prediction analysis uses MSC/NASTRAN stress, temperature and volume output, obtained from the use of three-dimensional, quadratic, isoparametric, or axisymmetric finite elements. The statistical fast fracture theories employed, along with selected input and output formats and options, are summarized. An example problem to demonstrate various features of the program is included.

  5. Advanced nondestructive examination technologies for measuring fatigue damage in nuclear power plant components

    SciTech Connect

    MacDonald, P.E.; Shah, V.N.; Akers, D.W.

    1995-12-01

    This paper presents recent results from an ongoing project at the Idaho National Engineering Laboratory (INEL) to develop advanced nondestructive methods to characterize the aging degradation of nuclear power plant pressure boundary components. One of the advanced methods, positron annihilation, is being developed for in situ characterization of fatigue damage in nuclear power plant piping and other components. This technique can detect and correlate the microstructural changes that are precursors of fatigue cracking in austenitic stainless steel components. In fact, the initial INEL test results show that the method can detect fatigue damage in stainless steel ranging from a few percent of the fatigue life up to 40 percent.

  6. Final Technical Report - Center for Technology for Advanced Scientific Component Software (TASCS)

    SciTech Connect

    Sussman, Alan

    2014-10-21

    This is a final technical report for the University of Maryland work in the SciDAC Center for Technology for Advanced Scientific Component Software (TASCS). The Maryland work focused on software tools for coupling parallel software components built using the Common Component Architecture (CCA) APIs. Those tools are based on the Maryland InterComm software framework that has been used in multiple computational science applications to build large-scale simulations of complex physical systems that employ multiple separately developed codes.

  7. Development of improved processing and evaluation methods for high reliability structural ceramics for advanced heat engine applications, Phase 1. Final report

    SciTech Connect

    Pujari, V.K.; Tracey, D.M.; Foley, M.R.; Paille, N.I.; Pelletier, P.J.; Sales, L.C.; Wilkens, C.A.; Yeckley, R.L.

    1993-08-01

    The program goals were to develop and demonstrate significant improvements in processing methods, process controls and non-destructive evaluation (NDE) which can be commercially implemented to produce high reliability silicon nitride components for advanced heat engine applications at temperatures to 1,370{degrees}C. The program focused on a Si{sub 3}N{sub 4}-4% Y{sub 2}O{sub 3} high temperature ceramic composition and hot-isostatic-pressing as the method of densification. Stage I had as major objectives: (1) comparing injection molding and colloidal consolidation process routes, and selecting one route for subsequent optimization, (2) comparing the performance of water milled and alcohol milled powder and selecting one on the basis of performance data, and (3) adapting several NDE methods to the needs of ceramic processing. The NDE methods considered were microfocus X-ray radiography, computed tomography, ultrasonics, NMR imaging, NMR spectroscopy, fluorescent liquid dye penetrant and X-ray diffraction residual stress analysis. The colloidal consolidation process route was selected and approved as the forming technique for the remainder of the program. The material produced by the final Stage II optimized process has been given the designation NCX 5102 silicon nitride. According to plan, a large number of specimens were produced and tested during Stage III to establish a statistically robust room temperature tensile strength database for this material. Highlights of the Stage III process demonstration and resultant database are included in the main text of the report, along with a synopsis of the NCX-5102 aqueous based colloidal process. The R and D accomplishments for Stage I are discussed in Appendices 1--4, while the tensile strength-fractography database for the Stage III NCX-5102 process demonstration is provided in Appendix 5. 4 refs., 108 figs., 23 tabs.

  8. New high boron content polyborane precursors to advanced ceramic materials: New syntheses, new applications

    NASA Astrophysics Data System (ADS)

    Guron, Marta

    There is a need for new synthetic routes to high boron content materials for applications as polymeric precursors to ceramics, as well as in neutron shielding and potential medical applications. To this end, new ruthenium-catalyzed olefin metathesis routes have been devised to form new complex polyboranes and polymeric species. Metathesis of di-alkenyl substituted o-carboranes allowed the synthesis of ring-closed products fused to the carborane cage, many of which are new compounds and one that offers a superior synthetic method to one previously published. Acyclic diene metathesis of di-alkenyl substituted m-carboranes resulted in the formation of new main-chain carborane-containing polymers of modest molecular weights. Due to their extremely low char yields, and in order to explore other metathesis routes, ring opening metathesis polymerization (ROMP) was used to generate the first examples of poly(norbornenyl- o-carboranes). Monomer synthesis was achieved via a two-step process, incorporating Ti-catalyzed hydroboration to make 6-(5-norbornenyl)-decaborane, followed by alkyne insertion in ionic liquid media to achieve 1,2-R2 -3-norbornenyl o-carborane species. The monomers were then polymerized using ROMP to afford several examples of poly(norbornenyl- o-carboranes) with relatively high molecular weights. One such polymer, [1-Ph, 3-(=CH2-C5H7-CH2=)-1,2-C 2B10H10]n, had a char yield very close to the theoretical char yield of 44%. Upon random copolymerization with poly(6-(5-norbornenyl) decaborane), char yields significantly increased to 80%, but this number was well above the theoretical value implicating the formation of a boron-carbide/carbon ceramic. Finally, applications of polyboranes were explored via polymer blends toward the synthesis of ceramic composites and the use of polymer precursors as reagents for potential ultra high temperature ceramic applications. Upon pyrolysis, polymer blends of poly(6-(5-norbornenyl)-decaborane) and poly

  9. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    1998-03-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO{sub 2} and H{sub 2} will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this reporting period, the construction and development of the chemical vapor deposition system was completed, and experiments were conducted on the deposition of alumina, silica, and aluminosilicates (such as mullite) from mixtures of AlCl{sub 3} and CH{sub 3}SiCl{sub 3} in CO{sub 2} and H{sub 2}. Work was mainly done on the investigation of the effects of the reaction temperature on the deposition kinetics. It was found that the temperature had a positive effect on the single oxides deposition rates and the codeposition rate. The apparent activation energy values extracted from the deposition rate vs. temperature curves in the high temperature region were similar for the three deposition processes, having a value around 20 kcal/mol. The codeposition rates were higher, by a

  10. Ceramic Technology Project. Semiannual progress report, April 1991--September 1991

    SciTech Connect

    Not Available

    1992-03-01

    The Ceramic Technology Project was developed by the USDOE Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS`s Materials Development Program, was developed to meet the ceramic technology requirements of the OTS`s automotive technology programs. Significant accomplishments in fabricating ceramic components for the USDOE and NASA advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. These programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. A five-year project plan was developed with extensive input from private industry. In July 1990 the original plan was updated through the estimated completion of development in 1993. The objective is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities.

  11. Ceramic fiber ceramic matrix filter development

    SciTech Connect

    Judkins, R.R.; Stinton, D.P.; Smith, R.G.; Fischer, E.M.

    1994-09-01

    The objectives of this project were to develop a novel type of candle filter based on a ceramic fiber-ceramic matrix composite material, and to extend the development to full-size, 60-mm OD by 1-meter-long candle filters. The goal is to develop a ceramic filter suitable for use in a variety of fossil energy system environments such as integrated coal gasification combined cycles (IGCC), pressurized fluidized-bed combustion (PFBC), and other advanced coal combustion environments. Further, the ceramic fiber ceramic matrix composite filter, hereinafter referred to as the ceramic composite filter, was to be inherently crack resistant, a property not found in conventional monolithic ceramic candle filters, such as those fabricated from clay-bonded silicon carbide. Finally, the adequacy of the filters in the fossil energy system environments is to be proven through simulated and in-plant tests.

  12. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    1997-10-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO{sub 2} and H{sub 2} will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this six-month reporting period, we continued the work on the development and construction of the thermogravimetric chemical vapor deposition system that we intend to employ for studying the deposition of alumina, silica, and aluminosilicates (such as mullite) from mixtures of metal chlorides in H{sub 2} and CO{sub 2}. Specifically, we worked on the development of the tubular flow reactor that will be used for producing aluminum chloride for delivery to the chemical vapor deposition system and of the vapor and gas supply system. Various problems arising from condensation of aluminum chlorides in some sections of the supply line were resolved, and we expect to perform experiments using mixtures containing AlCl{sub 3} in the next reporting period. Preliminary experiments on the

  13. FUNCTIONALY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    PROF. STRATIS V. SOTIRCHOS

    1998-10-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO2 and H2 will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this six-month reporting period, the experimental work on the investigation of the deposition of alumina, silica, and aluminosilicates from mixtures of methyltrichlorosilane (MTS), aluminum trichloride, carbon dioxide, and hydrogen was continued. Experiments were also conducted on the deposition processes of the simple oxides, alumina and silica, from mixtures containing only one chloride (AlCl3 and MTS, respectively). Deposition rate data were obtained in a relatively broad range of operating conditions: temperatures in the range 800-1000 o C, 100 Torr pressure, 0.006-0.015 AlCl3 feed mole fraction, 0.011- 0.027 CH3SiCl3 feed mole fraction, and 0.004-0.07 CO2 feed mole fraction, and various positions along the axis of the deposition reactor. Since the effect of temperature had been

  14. Slow Crack Growth Analysis of Advanced Structural Ceramics Under Combined Loading Conditions: Damage Assessment in Life Prediction Testing

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.

    2000-01-01

    Slow crack growth analysis was performed with three different loading histories including constant stress-rate/constant stress-rate testing (Case 1 loading), constant stress/constant stress-rate testing (Case 2 loading), and cyclic stress/constant stress-rate testing (Case 2 loading). Strength degradation due to slow crack growth and/or damage accumulation was determined numerically as a function of percentage of interruption time between the two loading sequences for a given loading history. The numerical solutions were examined with the experimental data determined at elevated temperatures using four different advanced ceramic materials, two silicon nitrides, one silicon carbide and one alumina for the Case 1 loading history, and alumina for the Case 3 loading history. The numerical solutions were in reasonable agreement with the experimental data, indicating that notwithstanding some degree of creep deformation presented for some test materials slow crack growth was a governing mechanism associated with failure for all the test materials.

  15. Slow Crack Growth Analysis of Advanced Structural Ceramics Under Combined Loading Conditions: Damage Assessment in Life Prediction Testing

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.

    2000-01-01

    Slow crack growth analysis was performed with three different loading histories including constant stress-rate/constant stress-rate testing (Case I loading), constant stress/constant stress-rate testing (Case II loading), and cyclic stress/constant stress-rate testing (Case III loading). Strength degradation due to slow crack growth arid/or damage accumulation was determined numerically as a Function of percentage of interruption time between the two loading sequences for a given loading history. The numerical solutions were examined with the experimental data determined at elevated temperatures using four different advanced ceramic materials, two silicon nitrides, one silicon carbide and one alumina for the Case I loading history, and alumina for the Case II loading history. The numerical solutions were in reasonable agreement with the experimental data, indicating that notwithstanding some degree of creep deformation presented for some test materials slow crack growth was a governing mechanism associated with failure for all the test material&

  16. Slow Crack Growth Analysis of Advanced Structural Ceramics Under Combined Loading Conditions: Damage Assessment in Life Prediction Testing

    NASA Technical Reports Server (NTRS)

    Choi, S. R.; Gyekenyesi, J. P.

    2001-01-01

    Slow crack growth analysis was performed with three different loading histories including constant stress- rate/constant stress-rate testing (Case I loading), constant stress/constant stress-rate testing (Case II loading), and cyclic stress/constant stress-rate testing (Case III loading). Strength degradation due to slow crack growth and/or damage accumulation was determined numerically as a function of percentage of interruption time between the two loading sequences for a given loading history. The numerical solutions were examined with the experimental data determined at elevated temperatures using four different advanced ceramic materials, two silicon nitrides, one silicon carbide and one alumina for the Case I loading history, and alumina for the Case II loading history. The numerical solutions were in reasonable agreement with the experimental data, indicating that notwithstanding some degree of creep deformation presented for some test materials slow crack growth was a governing mechanism associated with failure for all the rest materials.

  17. Plasma Processed Nanosized-Powders of Refractory Compounds for Obtaining Fine-Grained Advanced Ceramics

    NASA Astrophysics Data System (ADS)

    I, Zalite; J, Grabis; E, Palcevskis; M, Herrmann

    2011-10-01

    One of the ways for the production of ceramic materials with a fine-grained structure is the use of nanopowders. Different methods are used for the production of nanopowders. One of them is the method of plasmachemical synthesis. Different nanopowders of refractory materials can be obtained by this method. The preparation of nanosized powders of nitrides and oxides and their composites by the method of plasmachemical synthesis, the possibilities to receive nanopowders with different particle size and the potential advantages of nanopowders were investigated.

  18. Characterization of optical components using contact and non-contact interferometry techniques: advanced metrology for optical components

    NASA Astrophysics Data System (ADS)

    Yu, Yang; Conroy, Mike; Smith, Richard

    2012-10-01

    Advanced metrology plays an important role in the research, production and quality control of optical components. With surface finish, form error and other parameter specifications becoming more stringent, precision measurements are increasingly demanded by optics manufacturers and users. The modern metrologist now has both contact and noncontact measurement solutions available and a combination of these techniques now provides a more detailed understanding of optical components. Phase Grating Interferometry (PGI) with sub-nanometre vertical resolution and sub-micron lateral resolution can provide detailed characterization of a wide range of components including shallow and steep-sided optics. PGI is ideal for precision form measurement of a comprehensive range of lenses, moulds and other spherical or aspheric products. Because of the complex nature of these components, especially precision aspheric and asphero-diffractive optics, control of the form is vital to ensure they perform correctly. Recent hardware and software developments now make it possible to gain a better understanding and control of the form and function of this optics. Another change is the use of high speed 3D non-contact measurement of optics which is becoming more popular. Often scanning interferometric techniques such as coherence correlation interferometry (CCI) can be used to study components not suited to 2D contact analysis, including fragile surfaces and structured surfaces. Scanning interferometry can also be used to measure film thickness and uniformity of any coating present. In this paper the use of both PGI and CCI to measure optical lenses and coatings is discussed.

  19. The Production of Advanced Glass Ceramic HLW Forms using Cold Crucible Induction Melter

    SciTech Connect

    Veronica J Rutledge; Vince Maio

    2013-10-01

    Cold Crucible Induction Melters (CCIMs) will favorably change how High-Level radioactive Waste (from nuclear fuel recovery) is treated in the 21st century. Unlike the existing Joule-Heated Melters (JHMs) currently in operation for the glass-based immobilization of High-Level Waste (HLW), CCIMs offer unique material features that will increase melt temperatures, increase throughput, increase mixing, increase loading in the waste form, lower melter foot prints, eliminate melter corrosion and lower costs. These features not only enhance the technology for producing HLW forms, but also provide advantageous attributes to the waste form by allowing more durable alternatives to glass. This paper discusses advantageous features of the CCIM, with emphasis on features that overcome the historical issues with the JHMs presently utilized, as well as the benefits of glass ceramic waste forms over borosilicate glass waste forms. These advantages are then validated based on recent INL testing to demonstrate a first-of-a-kind formulation of a non-radioactive ceramic-based waste form utilizing a CCIM.

  20. Advanced Lubrication for Energy Efficiency, Durability and Lower Maintenance Costs of Advanced Naval Components and Systems

    DTIC Science & Technology

    2010-05-19

    softer, easily mechanically shearable components, pressure sensitive deformable ( exfoliable ) MoS2 nanoparticles and resulting transfer film, along...consists of loading stages. The rpm is constant at 1400 rpm and run for 15min on each stage with increasing load. When the wear scar on all teeth

  1. ASTM Committee C28: International Standards for Properties and Performance of Advanced Ceramics-Three Decades of High-Quality, Technically-Rigorous Normalization

    NASA Technical Reports Server (NTRS)

    Jenkins, Michael G.; Salem, Jonathan A.

    2016-01-01

    Physical and mechanical properties and performance of advanced ceramics and glasses are difficult to measure correctly without the proper techniques. For over three decades, ASTM Committee C28 on Advanced Ceramics, has developed high-quality, technically-rigorous, full-consensus standards (e.g., test methods, practices, guides, terminology) to measure properties and performance of monolithic and composite ceramics that may be applied to glasses in some cases. These standards contain testing particulars for many mechanical, physical, thermal, properties and performance of these materials. As a result these standards are used to generate accurate, reliable, repeatable and complete data. Within Committee C28, users, producers, researchers, designers, academicians, etc. have written, continually updated, and validated through round-robin test programs, 50 standards since the Committee's founding in 1986. This paper provides a detailed retrospective of the 30 years of ASTM Committee C28 including a graphical pictogram listing of C28 standards along with examples of the tangible benefits of standards for advanced ceramics to demonstrate their practical applications.

  2. Advanced Turbine Technology Applications Project (ATTAP)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Advanced Turbine Technologies Application Project (ATTAP) is in the fifth year of a multiyear development program to bring the automotive gas turbine engine to a state at which industry can make commercialization decisions. Activities during the past year included reference powertrain design updates, test-bed engine design and development, ceramic component design, materials and component characterization, ceramic component process development and fabrication, ceramic component rig testing, and test-bed engine fabrication and testing. Engine design and development included mechanical design, combustion system development, alternate aerodynamic flow testing, and controls development. Design activities included development of the ceramic gasifier turbine static structure, the ceramic gasifier rotor, and the ceramic power turbine rotor. Material characterization efforts included the testing and evaluation of five candidate high temperature ceramic materials. Ceramic component process development and fabrication, with the objective of approaching automotive volumes and costs, continued for the gasifier turbine rotor, gasifier turbine scroll, extruded regenerator disks, and thermal insulation. Engine and rig fabrication, testing, and development supported improvements in ceramic component technology. Total test time in 1992 amounted to 599 hours, of which 147 hours were engine testing and 452 were hot rig testing.

  3. Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

    SciTech Connect

    Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.; Ryan, M.A.; O'Connor, D.; Kikkert, S.

    1991-01-01

    Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double prime} alumina solid electrolyte (BASE), the seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.

  4. Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

    SciTech Connect

    Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.; Ryan, M.A.; O`Connor, D.; Kikkert, S.

    1991-12-31

    Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double_prime} alumina solid electrolyte (BASE), the seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.

  5. Deformation mechanisms in advanced structural ceramics due to indentation and scratch processes

    NASA Astrophysics Data System (ADS)

    Ghosh, Dipankar

    Plasma pressure compaction technique was used to develop boron carbide (B4C) and zirconium diboride-silicon carbide (ZrB2-SiC) composite. B4C ceramics are extensively used as body armor in military and civilian applications, and ZrB2-SiC composite has been recognized as a potential candidate for high-temperature aerospace applications. In this dissertation, processing parameters, quasistatic and high-strain rate mechanical response, and fundamental deformation mechanisms of these materials have been investigated. In the case of B4C, the rate sensitivity of indentation hardness was determined using a dynamic indentation hardness tester that can deliver loads in 100 micros. By comparing dynamic hardness with the static hardness, it was found that B4C exhibits a lower hardness at high-strain rate, contrary to known behavior in many structural ceramics. However, these results are consistent with the ballistic testing of B4C armors as reported in recent literature. This behavior was further investigated using a series of spectroscopic techniques such as visible and UV micro-Raman, photoluminescence and infrared. These studies not only confirmed that structural transformation occurred during indentation experiments similar to that in ballistic testing of B4C but also suggested a greater degree of structural changes under dynamic loading compared to static loading. Due to the potential application as external heat shields in supersonic vehicles, scratch studies were conducted on the ZrB2-SiC composite. These studies revealed metal-like slip-line patterns which are indeed an unusual in brittle solids at room-temperature. Utilizing classical stress field solutions under combined normal and tangential loads, a rationale was developed for understanding the formation of scratch-induced deformation features. Also, an analytical framework was developed, combining the concept of 'blister field' and the 'secular equation' relating Raman peaks to strain, to measure scratch

  6. Final Report for "Center for Technology for Advanced Scientific Component Software"

    SciTech Connect

    Svetlana Shasharina

    2010-12-01

    The goal of the Center for Technology for Advanced Scientific Component Software is to fundamentally changing the way scientific software is developed and used by bringing component-based software development technologies to high-performance scientific and engineering computing. The role of Tech-X work in TASCS project is to provide an outreach to accelerator physics and fusion applications by introducing TASCS tools into applications, testing tools in the applications and modifying the tools to be more usable.

  7. Ultra-Fast Fracture Strength of Advanced Ceramics at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Salem, Jonathan A.

    1998-01-01

    An attempt was made to determine elevated-temperature, 'ultra'-fast fracture strengths of one alumina, two silicon nitrides and one silicon carbide by using constant stress-rate ('dynamic fatigue') testing with a series of 'ultra'-fast test rates. Of the materials tested, the alumina exhibited a convergence of strength at stress rates below 3.3 x 10(exp 4) MPa/s. The strength approached approximately the room-temperature inert strength. By contrast, the silicon nitrides and silicon carbide did not reveal a strength approach, but exhibited elevated-temperature strengths 10 and 20% lower than their respective room-temperature strengths. Although the analytical results imply that the elevated-temperature 'inert' strength of a ceramic material can be obtained by using sufficiently high stress rates, the experimental testing rates were only sufficient to demonstrate convergence for the alumina.

  8. A method of producing very high resistivity surface conduction on ceramic accelerator components using metal ion implantation

    SciTech Connect

    F. Liu; I. Brown; L. Phillips; G. Biallas; T. Siggins

    1997-05-01

    An important technique used for the suppression of surface flashover on high voltage DC ceramic insulators as well as for RF windows is that of providing some surface conduction to bleed off accumulated surface charge. The authors have used metal ion implantation to modify the surface of high voltage ceramic vacuum insulators to provide a uniform surface resistivity of approximately 5 x 10{sup 10} Q{sup 2}. A vacuum arc ion source based implanter was used to implant Pt at an energy of about 135 MeV to doses of up to more than 5 x 10{sup 16} ions cm{sup 2} into small ceramic test coupons and also into the inside surface of several ceramic accelerator columns 25 cm I. D. by 28 cm long. Here they describe the experimental set-up used to do the ion implantation and summarize the results of their exploratory work on implantation into test coupons as well as the implantations of the actual ceramic columns.

  9. Highly integrated hybrid process with ceramic ultrafiltration-membrane for advanced treatment of drinking water: a pilot study.

    PubMed

    Guo, Jianning; Wang, Lingyun; Zhu, Jia; Zhang, Jianguo; Sheng, Deyang; Zhang, Xihui

    2013-01-01

    This article presents a highly integrated hybrid process for the advanced treatment of drinking water in dealing with the micro-polluted raw water. A flat sheet ceramic membrane with the pore size of 50∼60 nm for ultrafiltration (UF) is used to integrate coagulation and ozonation together. At the same time, biological activated carbon filtration (BAC) is used to remove the ammonia and organic pollutants in raw water. A pilot study in the scale of 120 m(3)/d has been conducted in Southern China. The mainly-analyzed parameters include turbidity, particle counts, ammonia, total organic carbon (TOC), UV254, biological dissolved organic carbon (BDOC), dissolved oxygen (DO) as well as trans-membrane pressure (TMP). The experiments demonstrated that ceramic UF-membrane was able to remove most of turbidity and suspended particulate matters. The final effluent turbidity reached to 0.14 NTU on average. BAC was effective in removing ammonia and organic matters. Dissolved oxygen (DO) is necessary for the biodegradation of ammonia at high concentration. The removal efficiencies reached to 90% for ammonia with the initial concentration of 3.6 mg/L and 76% for TOC with the initial concentration of 3.8 mg/L. Ozonation can alter the molecular structure of organics in terms of UV254, reduce membrane fouling, and extend the operation circle. It is believed the hybrid treatment process developed in this article can achieve high performance with less land occupation and lower cost compared with the conventional processes. It is especially suitable for the developing countries in order to obtain high-quality drinking water in a cost-effective way.

  10. Thermal and mechanical analysis of major components for the advanced adiabatic diesel engine

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The proposed design for the light duty diesel is an in-line four cylinder spark assisted diesel engine mounted transversely in the front of the vehicle. The engine has a one piece cylinder head, with one intake valve and one exhaust valve per cylinder. A flat topped piston is used with a cylindrical combustion chamber recessed into the cylinder head directly under the exhaust valve. A single ceramic insert is cast into the cylinder head to insulate both the combustion chamber and the exhaust port. A similar ceramic insert is cast into the head to insulate the intake port. A ceramic faceplate is pressed into the combustion face of the head to insulate the face of the head from hot combustion gas. The valve seats are machined directly into the ceramic faceplate for the intake valve and into the ceramic exhaust pot insert for the exhaust valve. Additional ceramic applications in the head are the use of ceramic valve guides and ceramic insulated valves. The ceramic valve guides are press fit into the head and are used for increased wear resistance. The ceramic insulated valves are conventional valves with the valve faces plasma spray coated with ceramic for insulation.

  11. IMPROVEMENT OF WEAR COMPONENT'S PERFORMANCE BY UTILIZING ADVANCED MATERIALS AND NEW MANUFACTURING TECHNOLOGIES: CASTCON PROCESS FOR MINING APPLICATIONS

    SciTech Connect

    Xiaodi Huang; Richard Gertsch

    2005-02-04

    Michigan Technological University, together with The Robbins Group, Advanced Ceramic Research, Advanced Ceramic Manufacturing, and Superior Rock Bits, evaluated a new process and a new material for producing drill bit inserts and disc cutters for the mining industry. Difficulties in the material preparation stage slowed the research initially. Prototype testing of the drill bit inserts showed that the new inserts did not perform up to the current state of the art. Due to difficulties in the prototype production of the disc cutters, the disc cutter was manufactured but not tested. Although much promising information was obtained as a result of this project, the objective of developing an effective means for producing rock drill bits and rock disc cutters that last longer, increase energy efficiency and penetration rate, and lower overall production cost was not met.

  12. 7 CFR 1000.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE GENERAL PROVISIONS OF FEDERAL MILK MARKETING ORDERS Class Prices § 1000.50 Class prices, component prices, and advanced pricing factors. Class prices per hundredweight of milk containing 3.5 percent...

  13. 7 CFR 1032.53 - Announcement of class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Announcement of class prices, component prices, and advanced pricing factors. 1032.53 Section 1032.53 Agriculture Regulations of the Department of Agriculture... MILK IN THE CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.53 Announcement...

  14. 7 CFR 1032.53 - Announcement of class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Announcement of class prices, component prices, and advanced pricing factors. 1032.53 Section 1032.53 Agriculture Regulations of the Department of Agriculture... MILK IN THE CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.53 Announcement...

  15. 7 CFR 1032.53 - Announcement of class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Announcement of class prices, component prices, and advanced pricing factors. 1032.53 Section 1032.53 Agriculture Regulations of the Department of Agriculture... MILK IN THE CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.53 Announcement...

  16. 7 CFR 1032.53 - Announcement of class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Announcement of class prices, component prices, and advanced pricing factors. 1032.53 Section 1032.53 Agriculture Regulations of the Department of Agriculture... MILK IN THE CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.53 Announcement...

  17. 7 CFR 1032.53 - Announcement of class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Announcement of class prices, component prices, and advanced pricing factors. 1032.53 Section 1032.53 Agriculture Regulations of the Department of Agriculture... MILK IN THE CENTRAL MARKETING AREA Order Regulating Handling Class Prices § 1032.53 Announcement...

  18. 7 CFR 1000.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE GENERAL PROVISIONS OF FEDERAL MILK MARKETING ORDERS Class Prices § 1000.50 Class prices, component prices, and advanced pricing factors. Class prices per hundredweight of milk containing 3.5 percent...

  19. 7 CFR 1000.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; MILK), DEPARTMENT OF AGRICULTURE GENERAL PROVISIONS OF FEDERAL MILK MARKETING ORDERS Class Prices § 1000.50 Class prices, component prices, and advanced pricing factors. Class prices per hundredweight of milk containing 3.5 percent...

  20. 7 CFR 1000.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; MILK), DEPARTMENT OF AGRICULTURE GENERAL PROVISIONS OF FEDERAL MILK MARKETING ORDERS Class Prices § 1000.50 Class prices, component prices, and advanced pricing factors. Class prices per hundredweight of milk containing 3.5 percent...

  1. 7 CFR 1000.50 - Class prices, component prices, and advanced pricing factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE GENERAL PROVISIONS OF FEDERAL MILK MARKETING ORDERS Class Prices § 1000.50 Class prices, component prices, and advanced pricing factors. Class prices per hundredweight of milk containing 3.5 percent...

  2. Development of Advanced In-Cylinder Components and Tribological Systems for Low Heat Rejection Diesel Engines

    NASA Technical Reports Server (NTRS)

    Yonushonis, T. M.; Wiczynski, P. D.; Myers, M. R.; Anderson, D. D.; McDonald, A. C.; Weber, H. G.; Richardson, D. E.; Stafford, R. J.; Naylor, M. G.

    1999-01-01

    In-cylinder components and tribological system concepts were designed, fabricated and tested at conditions anticipated for a 55% thermal efficiency heavy duty diesel engine for the year 2000 and beyond. A Cummins L10 single cylinder research engine was used to evaluate a spherical joint piston and connecting rod with 19.3 MPa (2800 psi) peak cylinder pressure capability, a thermal fatigue resistant insulated cylinder head, radial combustion seal cylinder liners, a highly compliant steel top compression ring, a variable geometry turbocharger, and a microwave heated particulate trap. Components successfully demonstrated in the final test included spherical joint connecting rod with a fiber reinforced piston, high conformability steel top rings with wear resistant coatings, ceramic exhaust ports with strategic oil cooling and radial combustion seal cylinder liner with cooling jacket transfer fins. A Cummins 6B diesel was used to develop the analytical methods, materials, manufacturing technology and engine components for lighter weight diesel engines without sacrificing performance or durability. A 6B diesel engine was built and tested to calibrate analytical models for the aluminum cylinder head and aluminum block.

  3. Use of ceramics in point-focus solar receivers

    NASA Technical Reports Server (NTRS)

    Smoak, R. H.; Kudirka, A. A.

    1981-01-01

    One of the research and development efforts in the Solar Thermal Energy Systems Project at the Jet Propulsion Laboratory has been focused on application of ceramic components for advanced point-focus solar receivers. The impetus for this effort is a need for high efficiency, low cost solar receivers which operate in a temperature regime where use of metal components is impractical. The current status of the work on evaluation of ceramic components at JPL and elsewhere is outlined and areas where lack of knowledge is currently slowing application of ceramics are discussed. Future developments of ceramic processing technology and reliability assurance methodology should open up applications for the point-focus solar concentrator system in fuels and chemicals production, in thermochemical energy transport and storage, in detoxification of hazardous materials and in high temperature process heat as well as for electric power generation.

  4. Assessment of strength limiting flaws in ceramic heat exchanger components: Phase 1, Final report, September 28, 1984-June 30, 1986

    SciTech Connect

    Powers, T.; Snyder, J.

    1986-10-01

    Assurance of energy efficient design lifetimes of high temperature structural ceramics requires the ability to specify acceptance criteria and to test to those criteria. These criteria will be established through nondestructive testing, to determine which defects are detectable, together with fracture mechanics, to calculate effects of indetectable flaws. The first phase of this program is to examine heat exchanger material with four test methods which have shown promise for use in ceramics; ultrasonic scanning, microfocus x-ray, Scanning Laser Acoustic Microscope, and Acoustic Holography. The capabilities, limits, and potential for improvement of these are presented in this report. Destructive testing, material sectioning, and fractography are included. 24 refs., 68 figs., 6 tabs.

  5. Advanced component development of MCFC technology at M-C Power

    SciTech Connect

    Erickson, D.S.; Haugh, E.J.; Benjamin, T.G.

    1996-12-31

    M-C Power Corporation (MCP) was founded in 1987 to commercialize Molten Carbonate Fuel Cell (MCFC) stacks. The first generation of active area cell components were successfully scaled-up from the 100-cm{sup 2} area laboratory scale to continuous production of commercial-area (1-m) components. These components have been tested in five commercial-area subscale (20-kW) stacks and one commercial-scale (250-kW) stack. The second 250 kW stack is being installed in the power plant for operation in late 1996 and components have already been manufactured for the third 250-kW stack which is scheduled to go on-line in the middle of 1997. Concurrent with commercial-area (1-m{sup 2}) active component manufacturing has been an ongoing effort to develop and test advanced component technologies that will enable MCP to meet its future cost and performance goals. The primary goal is to lower the total cell package cost, while attaining improvements in cell performance and endurance. This work is being completed through analysis of the cost drivers for raw materials and manufacturing techniques. A program is in place to verify the performance of the lower cost materials through pressurized (3 atm) bench scale (100-cm{sup 2}) cell tests. Bench-scale cell testing of advanced active area components has shown that simultaneous cost reduction and improvements in the performance and endurance are attainable. Following performance verification at the bench scale level, scale-up of the advanced component manufacturing processes to commercial-area has been ongoing in the past year. The following sections discuss some of the performance improvements and reductions in cost that have been realized.

  6. Advanced Turbine Technology Applications Project (ATTAP)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    ATTAP activities during the past year were highlighted by an extensive materials assessment, execution of a reference powertrain design, test-bed engine design and development, ceramic component design, materials and component characterization, ceramic component process development and fabrication, component rig design and fabrication, test-bed engine fabrication, and hot gasifier rig and engine testing. Materials assessment activities entailed engine environment evaluation of domestically supplied radial gasifier turbine rotors that were available at the conclusion of the Advanced Gas Turbine (AGT) Technology Development Project as well as an extensive survey of both domestic and foreign ceramic suppliers and Government laboratories performing ceramic materials research applicable to advanced heat engines. A reference powertrain design was executed to reflect the selection of the AGT-5 as the ceramic component test-bed engine for the ATTAP. Test-bed engine development activity focused on upgrading the AGT-5 from a 1038 C (1900 F) metal engine to a durable 1371 C (2500 F) structural ceramic component test-bed engine. Ceramic component design activities included the combustor, gasifier turbine static structure, and gasifier turbine rotor. The materials and component characterization efforts have included the testing and evaluation of several candidate ceramic materials and components being developed for use in the ATTAP. Ceramic component process development and fabrication activities were initiated for the gasifier turbine rotor, gasifier turbine vanes, gasifier turbine scroll, extruded regenerator disks, and thermal insulation. Component rig development activities included combustor, hot gasifier, and regenerator rigs. Test-bed engine fabrication activities consisted of the fabrication of an all-new AGT-5 durability test-bed engine and support of all engine test activities through instrumentation/build/repair. Hot gasifier rig and test-bed engine testing

  7. Microwave processing of ceramic oxide filaments. Annual report, FY1997

    SciTech Connect

    Vogt, G.J.

    1998-12-31

    The objective of the microwave filament processing project is to develop microwave techniques to manufacture continuous ceramic oxide filaments. Microwave processing uses the volumetric absorption of microwave power in oxide filament tows to drive off process solvents, to burn out organic binders, and to sinter the dried fibers to produce flexible, high-strength ceramic filaments. The technical goal is to advance filament processing technology by microwave heating more rapidly with less energy and at a lower cost than conventional processing, but with the same quality as conventional processing. The manufacturing goal is to collaborate with the 3M Company, a US manufacturer of ceramic oxide filaments, to evaluate the technology using a prototype filament system and to transfer the microwave technology to the 3M Company. Continuous ceramic filaments are a principal component in many advanced high temperature materials like continuous fiber ceramic composites (CFCC) and woven ceramic textiles. The use of continuous ceramic filaments in CFCC radiant burners, gas turbines, waste incineration, and hot gas filters in U.S. industry and power generation is estimated to save at least 2.16 quad/yr by year 2010 with energy cost savings of at least $8.1 billion. By year 2010, continuous ceramic filaments and CFCC`s have the potential to abate pollution emissions by 917,000 tons annually of nitrous oxide and 118 million tons annually of carbon dioxide (DOE Report OR-2002, February, 1994).

  8. Compatibility of selected ceramics with steam-methane reformer environments

    SciTech Connect

    Keiser, J.R.; Howell, M.; Williams, J.J.; Rosenberg, R.A.

    1996-04-01

    Conventional steam reforming of methane to synthesis gas (CO and H{sub 2}) hasa conversion efficiency of about 85%. Replacement of metal tubes in the reformer with ceramic tubes offers the potential for operation at temperatures high enough to increase the efficiency to 98-99%. However, the two candidate ceramic materials being given strongest consideration, sintered alpha Si carbide and Si carbide particulate-strengthened alumina, have been shown to react with components of the reformer environment. Extent of degradation as a function of steam partial pressure and exposure time has been studied, and results suggest limits under which these structural ceramics can be used in advanced steam-methane reformers.

  9. Development of Thin Film Ceramic Thermocouples for High Temperature Environments

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Farmer, Serene C.; Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

    2004-01-01

    The maximum use temperature of noble metal thin film thermocouples of 1100 C (2000 F) may not be adequate for use on components in the increasingly harsh conditions of advanced aircraft and next generation launch technology. Ceramic-based thermocouples are known for their high stability and robustness at temperatures exceeding 1500 C, but are typically found in the form of rods or probes. NASA Glenn Research Center is investigating the feasibility of ceramics as thin film thermocouples for extremely high temperature applications to take advantage of the stability and robustness of ceramics and the non-intrusiveness of thin films. This paper will discuss the current state of development in this effort.

  10. Synthesis of high performance ceramic fibers by chemical vapor deposition for advanced metallics reinforcing

    NASA Technical Reports Server (NTRS)

    Revankar, Vithal; Hlavacek, Vladimir

    1991-01-01

    The chemical vapor deposition (CVD) synthesis of fibers capable of effectively reinforcing intermetallic matrices at elevated temperatures which can be used for potential applications in high temperature composite materials is described. This process was used due to its advantage over other fiber synthesis processes. It is extremely important to produce these fibers with good reproducible and controlled growth rates. However, the complex interplay of mass and energy transfer, blended with the fluid dynamics makes this a formidable task. The design and development of CVD reactor assembly and system to synthesize TiB2, CrB, B4C, and TiC fibers was performed. Residual thermal analysis for estimating stresses arising form thermal expansion mismatch were determined. Various techniques to improve the mechanical properties were also performed. Various techniques for improving the fiber properties were elaborated. The crystal structure and its orientation for TiB2 fiber is discussed. An overall view of the CVD process to develop CrB2, TiB2, and other high performance ceramic fibers is presented.

  11. Advances in Determining Soil Matric Potential Using an Engineered Porous Ceramic and Dielectric Permittivity

    NASA Astrophysics Data System (ADS)

    Cobos, D. R.; Campbell, C. S.; Campbell, G. S.

    2007-12-01

    Soil water potential is a key parameter for determining water availability for plant growth, water flow, and soil stability. Although an in situ measurement of matric potential has been the focus of considerable research over the years, existing solutions still have many draw backs such as high maintenance, limited longevity, individual calibration requirements, high cost, and small measurement range. The objective of this research was to develop a sensor that could be used in the field to accurately measure soil matric potential without the limitations noted above. The sensor, which consisted of a dielectric sensor sandwiched between porous ceramic, was tested over a range soil types, electrical conductivties, and temperatures to calibrate and characterize its output. Data show consistent calibration curves between sensor output and actual soil matric potential over a variety of soil textures and electrical conductivities. Although temperature showed an effect on sensor output, it was low compared to overall sensor output. Likewise, salt effects were not visible in saturated matrices up to 10 dS/m. Data suggest the sensor will be an effective and robust tool to determine in situ matric potential.

  12. Advanced Gas Turbine (AGT)

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The development and progress of the Advanced Gas Turbine engine program is examined. An analysis of the role of ceramics in the design and major engine components is included. Projected fuel economy, emissions and performance standards, and versatility in fuel use are also discussed.

  13. Advanced Turbine Technology Applications Project (ATTAP)

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Reports technical effort by AlliedSignal Engines in sixth year of DOE/NASA funded project. Topics include: gas turbine engine design modifications of production APU to incorporate ceramic components; fabrication and processing of silicon nitride blades and nozzles; component and engine testing; and refinement and development of critical ceramics technologies, including: hot corrosion testing and environmental life predictive model; advanced NDE methods for internal flaws in ceramic components; and improved carbon pulverization modeling during impact. ATTAP project is oriented toward developing high-risk technology of ceramic structural component design and fabrication to carry forward to commercial production by 'bridging the gap' between structural ceramics in the laboratory and near-term commercial heat engine application. Current ATTAP project goal is to support accelerated commercialization of advanced, high-temperature engines for hybrid vehicles and other applications. Project objectives are to provide essential and substantial early field experience demonstrating ceramic component reliability and durability in modified, available, gas turbine engine applications; and to scale-up and improve manufacturing processes of ceramic turbine engine components and demonstrate application of these processes in the production environment.

  14. Fermentation broth components influence droplet coalescence and hinder advanced biofuel recovery during fermentation.

    PubMed

    Heeres, Arjan S; Schroën, Karin; Heijnen, Joseph J; van der Wielen, Luuk A M; Cuellar, Maria C

    2015-08-01

    Developments in synthetic biology enabled the microbial production of long chain hydrocarbons, which can be used as advanced biofuels in aviation or transportation. Currently, these fuels are not economically competitive due to their production costs. The current process offers room for improvement: by utilizing lignocellulosic feedstock, increasing microbial yields, and using cheaper process technology. Gravity separation is an example of the latter, for which droplet growth by coalescence is crucial. The aim of this study was to study the effect of fermentation broth components on droplet coalescence. Droplet coalescence was measured using two setups: a microfluidic chip and regular laboratory scale stirred vessel (2 L). Some fermentation broth components had a large impact on droplet coalescence. Especially components present in hydrolysed cellulosic biomass and mannoproteins from the yeast cell wall retard coalescence. To achieve a technically feasible gravity separation that can be integrated with the fermentation, the negative effects of these components on coalescence should be minimized. This could be achieved by redesign of the fermentation medium or adjusting the fermentation conditions, aiming to minimize the release of surface active components by the microorganisms. This way, another step can be made towards economically feasible advanced biofuel production.

  15. Materials Development Program: Ceramic Technology Project bibliography, 1984--1992

    SciTech Connect

    Not Available

    1994-03-01

    The Ceramic Technology [for Advanced Heat Engines] Project was begun in 1983 to meet the ceramic materials needs of the companion DOE automotive engine program, the Advanced Gas Turbine (AGT) project, and the Heavy Duty Transport (low-heat-rejection, heavy-duty diesel) project. Goal is to develop an industry technology base for reliable and cost effective ceramics for applications in advanced automotive gas turbine and diesel engines. Research areas were identified following extensive input from industry and academia. Majority of research is done by industry (60%); work is also done at colleges and universities, in-house, and at other national laboratories and government agencies. In the beginning, reliability of ceramic components was the key issue. The reliability issues have largely been met and, at the present time, cost is the driving issue, especially in light of the highly cost-sensitive automotive market. Emphasis of the program has now been shifted toward developing cost-effective ceramic components for high-performance engines in the near-term. This bibliography is a compilation of publications done in conjunction with the Ceramic Technology Project since its beginning. Citations were obtained from reports done by participants in the project. We have tried to limit citations to those published and easily located. The end date of 1992 was selected.

  16. Studies of dynamic contact of ceramics and alloys for advanced heat engines. Final report

    SciTech Connect

    Gaydos, P.A.; Dufrane, K.F.

    1993-06-01

    Advanced materials and coatings for low heat rejection engines have been investigated for almost a decade. Much of the work has concentrated on the critical wear interface between the piston ring and cylinder liner. Simplified bench tests have identified families of coatings with high temperature wear performance that could meet or exceed that of conventional engine materials at today`s operating temperatures. More recently, engine manufacturers have begun to optimize material combinations and manufacturing processes so that the materials not only have promising friction and wear performance but are practical replacements for current materials from a materials and manufacturing cost standpoint. In this study, the advanced materials supplied by major diesel engine manufacturers were evaluated in an experimental apparatus that simulates many of the in-cylinder conditions of a low heat rejection diesel engine. Results include ring wear factors and average dynamic friction coefficients measured at intervals during the test. These results are compared with other advanced materials tested in the past as well as the baseline wear of current engines. Both fabricated specimens and sections of actual ring and cylinder liners were used in the testing. Observations and relative friction and wear performance of the individual materials are provided.

  17. Artificial Voids In Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Generazio, Edward R.; Baaklini, George Y.

    1988-01-01

    Method for creating voids in ceramic specimens developed. Silicon carbide and silicon nitride are high-temperature structural ceramic materials considered for applications in advanced gas-turbine engines. Ability to detect and characterize voids (by sizes, shapes, and locations) in structural ceramics vital for increasing strengths and reliabilities of materials. Small holes made deliberately to help quantify techniques of nondestructive evaluation.

  18. Center for Technology for Advanced Scientific Component Software (TASCS) Consolidated Progress Report July 2006 - March 2009

    SciTech Connect

    Bernholdt, D E; McInnes, L C; Govindaraju, M; Bramley, R; Epperly, T; Kohl, J A; Nieplocha, J; Armstrong, R; Shasharina, S; Sussman, A L; Sottile, M; Damevski, K

    2009-04-14

    A resounding success of the Scientific Discovery through Advanced Computing (SciDAC) program is that high-performance computational science is now universally recognized as a critical aspect of scientific discovery [71], complementing both theoretical and experimental research. As scientific communities prepare to exploit unprecedented computing capabilities of emerging leadership-class machines for multi-model simulations at the extreme scale [72], it is more important than ever to address the technical and social challenges of geographically distributed teams that combine expertise in domain science, applied mathematics, and computer science to build robust and flexible codes that can incorporate changes over time. The Center for Technology for Advanced Scientific Component Software (TASCS) tackles these issues by exploiting component-based software development to facilitate collaborative high-performance scientific computing.

  19. Center for Center for Technology for Advanced Scientific Component Software (TASCS)

    SciTech Connect

    Kostadin, Damevski

    2015-01-25

    A resounding success of the Scientific Discovery through Advanced Computing (SciDAC) program is that high-performance computational science is now universally recognized as a critical aspect of scientific discovery [71], complementing both theoretical and experimental research. As scientific communities prepare to exploit unprecedented computing capabilities of emerging leadership-class machines for multi-model simulations at the extreme scale [72], it is more important than ever to address the technical and social challenges of geographically distributed teams that combine expertise in domain science, applied mathematics, and computer science to build robust and flexible codes that can incorporate changes over time. The Center for Technology for Advanced Scientific Component Software (TASCS)1 tackles these these issues by exploiting component-based software development to facilitate collaborative high-performance scientific computing.

  20. Advanced Diesel Engine Component Development Program, final report - tasks 4-14

    SciTech Connect

    Kaushal, T.S.; Weber, K.E.

    1994-11-01

    The Advanced Diesel Engine Component Development (ADECD) Program is a multi-year, multi-phase effort to develop and demonstrate the critical technology needed to advance the heavy-duty low heat rejection (LHR) engine concept for the long-haul, heavy-duty truck market. The ADECD Program has been partitioned into two phases. The first phase, Phase 1, was completed in 1986, resulting in definition of the Advanced Diesel Reference Engine (ADRE)III. The second phase, Phase 11/111, examines the feasibility of the ADRE concepts for application to the on-highway diesel engine. Phase 11/111 is currently underway. This project is sponsored by the U.S. Department of Energy, Office of Transportation Technologies. The work has been performed by the Detroit Diesel Corporation (DDC) under Contract DEN3-329 with the NASA Lewis Research Center, who provide project management and technical direction.

  1. Study of advanced techniques for determining the long term performance of components

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The application of existing and new technology to the problem of determining the long-term performance capability of liquid rocket propulsion feed systems is discussed. The long term performance of metal to metal valve seats in a liquid propellant fuel system is stressed. The approaches taken in conducting the analysis are: (1) advancing the technology of characterizing components through the development of new or more sensitive techniques and (2) improving the understanding of the physical of degradation.

  2. Clinical application of bio ceramics

    NASA Astrophysics Data System (ADS)

    Anu, Sharma; Gayatri, Sharma

    2016-05-01

    Ceramics are the inorganic crystalline material. These are used in various field such as biomedical, electrical, electronics, aerospace, automotive and optical etc. Bio ceramics are the one of the most active areas of research. Bio ceramics are the ceramics which are biocompatible. The unique properties of bio ceramics make them an attractive option for medical applications and offer some potential advantages over other materials. During the past three decades, a number of major advances have been made in the field of bio ceramics. This review focuses on the use of these materials in variety of clinical scenarios.

  3. Ceramic Seal.

    SciTech Connect

    Smartt, Heidi A.; Romero, Juan A.; Custer, Joyce Olsen; Hymel, Ross W.; Krementz, Dan; Gobin, Derek; Harpring, Larry; Martinez-Rodriguez, Michael; Varble, Don; DiMaio, Jeff; Hudson, Stephen

    2016-11-01

    Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

  4. Advanced Fuels for LWRs: Fully-Ceramic Microencapsulated and Related Concepts FY 2012 Interim Report

    SciTech Connect

    R. Sonat Sen; Brian Boer; John D. Bess; Michael A. Pope; Abderrafi M. Ougouag

    2012-03-01

    This report summarizes the progress in the Deep Burn project at Idaho National Laboratory during the first half of fiscal year 2012 (FY2012). The current focus of this work is on Fully-Ceramic Microencapsulated (FCM) fuel containing low-enriched uranium (LEU) uranium nitride (UN) fuel kernels. UO2 fuel kernels have not been ruled out, and will be examined as later work in FY2012. Reactor physics calculations confirmed that the FCM fuel containing 500 mm diameter kernels of UN fuel has positive MTC with a conventional fuel pellet radius of 4.1 mm. The methodology was put into place and validated against MCNP to perform whole-core calculations using DONJON, which can interpolate cross sections from a library generated using DRAGON. Comparisons to MCNP were performed on the whole core to confirm the accuracy of the DRAGON/DONJON schemes. A thermal fluid coupling scheme was also developed and implemented with DONJON. This is currently able to iterate between diffusion calculations and thermal fluid calculations in order to update fuel temperatures and cross sections in whole-core calculations. Now that the DRAGON/DONJON calculation capability is in place and has been validated against MCNP results, and a thermal-hydraulic capability has been implemented in the DONJON methodology, the work will proceed to more realistic reactor calculations. MTC calculations at the lattice level without the correct burnable poison are inadequate to guarantee zero or negative values in a realistic mode of operation. Using the DONJON calculation methodology described in this report, a startup core with enrichment zoning and burnable poisons will be designed. Larger fuel pins will be evaluated for their ability to (1) alleviate the problem of positive MTC and (2) increase reactivity-limited burnup. Once the critical boron concentration of the startup core is determined, MTC will be calculated to verify a non-positive value. If the value is positive, the design will be changed to require

  5. Environmental Barrier Coatings for Ceramics and Ceramic Composites

    NASA Technical Reports Server (NTRS)

    Lee, Kang N.; Fox, Dennis; Eldridge, Jeffrey; Robinson, R. Craig; Bansal, Narottam

    2004-01-01

    One key factor that limits the performance of current gas turbine engines is the temperature capability of hot section structural components. Silicon-based ceramics, such as SiC/SiC composites and monolithic Si3N4, are leading candidates to replace superalloy hot section components in the next generation gas turbine engines due to their excellent high temperature properties. A major stumbling block to realizing Si-based ceramic hot section components is the recession of Si-based ceramics in combustion environments due to the volatilization of silica scale by water vapor. An external environmental barrier coating (EBC) is the most promising approach to preventing the recession. Current EBCs are based on silicon, mullite (3A12O3-2SiO2) and BSAS (barium strontium aluminum silicate with celsian structure). Volatility of BSAS, BSAS-silica chemical reaction, and low melting point of silicon limit the durability and temperature capability of current EBCs. Research is underway to develop EBCs with longer life and enhanced temperature capability. Understanding key issues affecting the performance of current EBCs is necessary for successful development of advanced EBCs. These issues include stress, chemical compatibility, adherence, and water vapor stability. Factors that affect stress are thermal expansion mismatch, phase stability, chemical stability, elastic modulus, etc. The current understanding on these issues will be discussed.

  6. Demasking the integrated value of discharge - Advanced sensitivity analysis on the components of hydrological models

    NASA Astrophysics Data System (ADS)

    Guse, Björn; Pfannerstill, Matthias; Gafurov, Abror; Fohrer, Nicola; Gupta, Hoshin

    2016-04-01

    The hydrologic response variable most often used in sensitivity analysis is discharge which provides an integrated value of all catchment processes. The typical sensitivity analysis evaluates how changes in the model parameters affect the model output. However, due to discharge being the aggregated effect of all hydrological processes, the sensitivity signal of a certain model parameter can be strongly masked. A more advanced form of sensitivity analysis would be achieved if we could investigate how the sensitivity of a certain modelled process variable relates to the changes in a parameter. Based on this, the controlling parameters for different hydrological components could be detected. Towards this end, we apply the approach of temporal dynamics of parameter sensitivity (TEDPAS) to calculate the daily sensitivities for different model outputs with the FAST method. The temporal variations in parameter dominance are then analysed for both the modelled hydrological components themselves, and also for the rates of change (derivatives) in the modelled hydrological components. The daily parameter sensitivities are then compared with the modelled hydrological components using regime curves. Application of this approach shows that when the corresponding modelled process is investigated instead of discharge, we obtain both an increased indication of parameter sensitivity, and also a clear pattern showing how the seasonal patterns of parameter dominance change over time for each hydrological process. By relating these results with the model structure, we can see that the sensitivity of model parameters is influenced by the function of the parameter. While capacity parameters show more sensitivity to the modelled hydrological component, flux parameters tend to have a higher sensitivity to rates of change in the modelled hydrological component. By better disentangling the information hidden in the discharge values, we can use sensitivity analyses to obtain a clearer signal

  7. Ceramic laser materials

    NASA Astrophysics Data System (ADS)

    Ikesue, Akio; Aung, Yan Lin

    2008-12-01

    The word 'ceramics' is derived from the Greek keramos, meaning pottery and porcelain. The opaque and translucent cement and clay often used in tableware are not appropriate for optical applications because of the high content of optical scattering sources, that is, defects. Recently, scientists have shown that by eliminating the defects, a new, refined ceramic material - polycrystalline ceramic - can be produced. This advanced ceramic material offers practical laser generation and is anticipated to be a highly attractive alternative to conventional glass and single-crystal laser technologies in the future. Here we review the history of the development of ceramic lasers, the principle of laser generation based on this material, some typical results achieved with ceramic lasers so far, and discuss the potential future outlook for the field.

  8. Advanced Turbine Technology Applications Project (ATTAP) 1993 annual report

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This report summarizes work performed by AlliedSignal Engines, a unit of AlliedSignal Aerospace Company, during calendar year 1993, toward development and demonstration of structural ceramic technology for automotive gas turbine engines. This work was performed for the U.S. Department of Energy (DOE) under National Aeronautics and Space Administration (NASA) Contract DEN3-335, Advanced Turbine Technology Applications Project (ATFAP). During 1993, the test bed used to demonstrate ceramic technology was changed from the AlliedSignal Engines/Garrett Model AGT101 regenerated gas turbine engine to the Model 331-200(CT) engine. The 331-200(CT) ceramic demonstrator is a fully-developed test platform based on the existing production AlliedSignal 331-200(ER) gas turbine auxiliary power unit (APU), and is well suited to evaluating ceramic turbine blades and nozzles. In addition, commonality of the 331-200(CT) engine with existing gas turbine APU's in commercial service provides the potential for field testing of ceramic components. The 1993 ATTAP activities emphasized design modifications of the 331-200 engine test bed to accommodate ceramic first-stage turbine nozzles and blades, fabrication of the ceramic components, ceramic component proof and rig tests, operational tests of the test bed equipped with the ceramic components, and refinement of critical ceramic design technologies.

  9. Development of nondestructive evaluation techniques for high-temperature ceramic heat exchanger components. Eleventh quarterly report, April-June 1980

    SciTech Connect

    Not Available

    1980-08-01

    One of the problems associated with ultrasonic inspection of silicon carbide tubes from the bore side, for wall-thickness measurements or detection of laminar flaws, is the mode conversion of nominally normal-incidence longitudinal waves to shear waves. Under the right circumstances the shear wave can be detected by the transducer after it converts back to a longitudinal wave, and can be confused with a legitimate flaw signal. This phenomenon occurs because of the sharp curvature of the tube and the width of the ultrasonic beam. The effect is discussed in some detail in the present report; reducing the width of the ultrasonic beam to approx. 1 mm is shown to virtually eliminate the problem while not reducing the signal amplitude of the backwall echoes significantly (i.e., by > 5 dB). Infrared techniques have been applied to inspection of glass-adhesive overlap joints in silicon carbide tubes. The results suggest that infrared techniques may be employed successfully in characterizing ceramic overlap joints through observation of heat-flow patterns. Results of previous efforts had led to the conclusion that holographic interferometry, although sensitive to surface flaws, would be difficult to use as a general inspection method for ceramic materials. This technique needs to be reassessed with respect to ceramic joints for two reasons. One is that the irregular geometry of many joints makes ultrasonic signal interpretation difficult, but leaves open the possibility of detecting flaws indirectly by looking for regions of high strain. The other reason for a new look at holography is that the introduction of a television camera and videotape system has made the production and evaluation of holographic interferograms much easier.

  10. Ceramic Integration Technologies for Energy and Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Asthana, Ralph N.

    2007-01-01

    Robust and affordable integration technologies for advanced ceramics are required to improve the performance, reliability, efficiency, and durability of components, devices, and systems based on them in a wide variety of energy, aerospace, and environmental applications. Many thermochemical and thermomechanical factors including joint design, analysis, and optimization must be considered in integration of similar and dissimilar material systems.

  11. Ceramic technology for automotive turbines

    NASA Technical Reports Server (NTRS)

    Mclean, A. F.

    1982-01-01

    The paper presents an update on ceramic technology for automotive turbines. Progress in research and development of improved ceramics is reviewed, including approaches for assessing time-dependent strength characteristics. Processes for making shapes are discussed, and the design and testing of selected ceramic turbine components are reviewed.

  12. Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

    NASA Astrophysics Data System (ADS)

    Mohan Reddy, M.; Gorin, Alexander; Abou-El-Hossein, K. A.

    2011-02-01

    Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

  13. Overview of NASA Studies on High-Temperature Ceramic Fibers

    NASA Technical Reports Server (NTRS)

    DiCarlo, James A.; Yun, Hee Mann

    2001-01-01

    NASA, DOD, and DOE are currently looking to the NASA UEET Program to develop ceramic matrix composites (CMC) for hot-section components in advanced power and propulsion systems - Success will depend strongly on developing ceramic fibers with a variety of key thermostructural properties, in particular, high as-produced tensile strength and retention of a large fraction of this strength for long times under the anticipated CMC service conditions. - Current UEET approach centers on selecting the optimum fiber type from commercially available fibers since the costs for development of advanced fibers are high and the markets for high-temperature CMC have yet to be established.

  14. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a recirculating control loop which had no water quality maintenance. Results show that periodic water maintenance can improve performance of the SWME. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage of this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing sublimator technology. The driver for the evaluation of water recirculation maintenance components was to enhance the robustness of the SWME through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A patented bed design that was developed for a United Technologies Aerospace System military application provided a low pressure drop means for water maintenance in the SWME recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for the ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  15. Structure-Property Relationships in Surface-Modified Ceramics. NATO advanced Science Institutes, Series E: Applied Sciences, Volume 170

    DTIC Science & Technology

    1989-01-01

    PROPERTIES OF CERAMICS AND THEIR STUDY BY COMPUTER SIMULATION METHODS ... 1 C.R.A. Catlow DISORDER, RANDOMNESS, AND AMORPHOUS PHASES...Federal Republic of Germany PROPERTIES OF CERAMICS AND THEIR STUDY BY COMPUTER SIMULATION METHODS C. R. A. Catlow Department of Chemistry, University...considerable success over the last ten years. Static and dynamical methods have been used, and the techniques have been applied with success to both bulk

  16. Advanced Materials and Component Development for Lithium-ion Cells for NASA Missions

    NASA Technical Reports Server (NTRS)

    Reid, Concha M.

    2012-01-01

    Human missions to Near Earth Objects, such as asteroids, planets, moons, libration points, and orbiting structures, will require safe, high specific energy, high energy density batteries to provide new or extended capabilities than are possible with today s state-of-the-art aerospace batteries. The National Aeronautics and Space Administration is developing advanced High Energy and Ultra High Energy lithium-ion cells to address these needs. In order to meet the performance goals, advanced, high-performing materials are required to provide improved performance at the component-level that contributes to performance at the integrated cell level. This paper will provide an update on the performance of experimental materials through the completion of two years of development. The progress of materials development, remaining challenges, and an outlook for the future of these materials in near term cell products will be discussed.

  17. Advanced Residuals Analysis for Determining the Number of PARAFAC Components in Dissolved Organic Matter.

    PubMed

    Cuss, Chad W; Guéguen, Céline; Andersson, Per; Porcelli, Don; Maximov, Trofim; Kutscher, Liselott

    2016-02-01

    Parallel factor analysis (PARAFAC) has facilitated an explosion in research connecting the fluorescence properties of dissolved organic matter (DOM) to its functions and biogeochemical cycling in natural and engineered systems. However, the validation of robust PARAFAC models using split-half analysis requires an oft unrealistically large number (hundreds to thousands) of excitation-emission matrices (EEMs), and models with too few components may not adequately describe differences between DOM. This study used self-organizing maps (SOM) and comparing changes in residuals with the effects of adding components to estimate the number of PARAFAC components in DOM from two data sets: MS (110 EEMs from nine leaf leachates and headwaters) and LR (64 EEMs from the Lena River). Clustering by SOM demonstrated that peaks clearly persisted in model residuals after validation by split-half analysis. Plotting the changes to residuals was an effective method for visualizing the removal of fluorophore-like fluorescence caused by increasing the number of PARAFAC components. Extracting additional PARAFAC components via residuals analysis increased the proportion of correctly identified size-fractionated leaf leachates from 56.0 ± 0.8 to 75.2 ± 0.9%, and from 51.7 ± 1.4 to 92.9 ± 0.0% for whole leachates. Model overfitting was assessed by considering the correlations between components, and their distributions amongst samples. Advanced residuals analysis improved the ability of PARAFAC to resolve the variation in DOM fluorescence, and presents an enhanced validation approach for assessing the number of components that can be used to supplement the potentially misleading results of split-half analysis.

  18. Design and characterization of Yb and Nd doped transparent ceramics for high power laser applications: recent advancements

    NASA Astrophysics Data System (ADS)

    Lapucci, A.; Vannini, M.; Ciofini, M.; Pirri, A.; Nikl, M.; Li, J.; Esposito, L.; Biasini, V.; Hostasa, J.; Goto, T.; Boulon, G.; Maksimov, R.; Gizzi, L.; Labate, L.; Toci, G.

    2017-01-01

    We report a review on our recent developments in Yttebium and Neodymium doped laser ceramics, along two main research lines. The first is the design and development of Yb:YAG ceramics with non uniform doping distribution, for the management of thermo-mechanical stresses and for the mitigation of ASE: layered structures have been produced by solid state reactive sintering, using different forming processes (spray drying and cold press of the homogenized powders, tape cast of the slurry); samples have been characterized and compared to FEM analysis. The second is the investigation of Lutetium based ceramics (such as mixed garnets LuYAG and Lu2O3); this interest is mainly motivated by the favorable thermal properties of these hosts under high doping. We recently obtained for the first time high efficiency laser emission from Yb doped LuYAG ceramics. The investigation on sesquioxides has been focused on Nddoped Lu2O3 ceramics, fabricated with the Spark Plasma Sintering method (SPS). We recently achieved the first laser emission above 1 W from Nd doped Lu2O3 ceramics fabricated by SPS.

  19. Boeing Helicopters Advanced Rotorcraft Transmission (ART) Program summary of component tests

    NASA Technical Reports Server (NTRS)

    Lenski, Joseph W., Jr.; Valco, Mark J.

    1992-01-01

    The principal objectives of the ART program are briefly reviewed, and the results of advanced technology component tests are summarized. The tests discussed include noise reduction by active cancellation, hybrid bidirectional tapered roller bearings, improved bearing life theory and friction tests, transmission lube study with hybrid bearings, and precision near-net-shape forged spur gears. Attention is also given to the study of high profile contact ratio noninvolute tooth form spur gears, parallel axis gear noise study, and surface modified titanium accessory spur gears.

  20. Boeing Helicopters Advanced Rotorcraft Transmission (ART) Program summary of component tests

    NASA Astrophysics Data System (ADS)

    Lenski, Joseph W., Jr.; Valco, Mark J.

    1992-07-01

    The principal objectives of the ART program are briefly reviewed, and the results of advanced technology component tests are summarized. The tests discussed include noise reduction by active cancellation, hybrid bidirectional tapered roller bearings, improved bearing life theory and friction tests, transmission lube study with hybrid bearings, and precision near-net-shape forged spur gears. Attention is also given to the study of high profile contact ratio noninvolute tooth form spur gears, parallel axis gear noise study, and surface modified titanium accessory spur gears.

  1. Robust Joining and Assembly of Ceramic Matrix Composites for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay

    2003-01-01

    Advanced ceramic matrix composites (CMCs) are under active consideration for use in a wide variety of high temperature applications within the aerospace, energy, and nuclear industries. The engineering designs of CMC components require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing of high temperature joints in ceramic matrix composites will be presented. A wide variety of ceramic composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and mechanical properties of joints in melt infiltrated and CVI Sic matrix composites will be reported. Various joint design philosophies and design issues in joining of composites will be discussed.

  2. Biomechanical behavior of a cemented ceramic knee replacement under worst case scenarios

    NASA Astrophysics Data System (ADS)

    Kluess, D.; Mittelmeier, W.; Bader, R.

    2009-12-01

    In connection with technological advances in the manufacturing of medical ceramics, a newly developed ceramic femoral component was introduced in total knee arthroplasty (TKA). The motivation to consider ceramics in TKA is based on the allergological and tribological benefits as proven in total hip arthroplasty. Owing to the brittleness and reduced fracture toughness of ceramic materials, the biomechanical performance has to be examined intensely. Apart from standard testing, we calculated the implant performance under different worst case scenarios including malposition, bone defects and stumbling. A finite-element-model was developed to calculate the implant performance in situ. The worst case conditions revealed principal stresses 12.6 times higher during stumbling than during normal gait. Nevertheless, none of the calculated principal stress amounts were above the critical strength of the ceramic material used. The analysis of malposition showed the necessity of exact alignment of the implant components.

  3. Biomechanical behavior of a cemented ceramic knee replacement under worst case scenarios

    NASA Astrophysics Data System (ADS)

    Kluess, D.; Mittelmeier, W.; Bader, R.

    2010-03-01

    In connection with technological advances in the manufacturing of medical ceramics, a newly developed ceramic femoral component was introduced in total knee arthroplasty (TKA). The motivation to consider ceramics in TKA is based on the allergological and tribological benefits as proven in total hip arthroplasty. Owing to the brittleness and reduced fracture toughness of ceramic materials, the biomechanical performance has to be examined intensely. Apart from standard testing, we calculated the implant performance under different worst case scenarios including malposition, bone defects and stumbling. A finite-element-model was developed to calculate the implant performance in situ. The worst case conditions revealed principal stresses 12.6 times higher during stumbling than during normal gait. Nevertheless, none of the calculated principal stress amounts were above the critical strength of the ceramic material used. The analysis of malposition showed the necessity of exact alignment of the implant components.

  4. Ceramic Technology Project, semiannual progress report for October 1993 through March 1994

    SciTech Connect

    Johnson, D.R.

    1994-09-01

    The Ceramic Technology Project was originally developed by the Department of Energy`s Office of Transportation Systems (OTS) in Conservation and Renewable Energy. Significant accomplishments in fabricating ceramic components for the Department of Energy (DOE), National Aeronautics and Space Administration (NASA), and Department of Defense (DoD) advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. An assessment of needs was completed, and a five-year project plan was developed with extensive input from private industry. In July 1990, the original plan was updated through the estimated completion of development in 1993. The original objective of the project was to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. During the course of the Ceramic Technology Project, remarkable progress has been made in the development of reliable structural ceramics. The direction of the Ceramic Technology Project is now shifting toward reducing the cost of ceramics to facilitate commercial introduction of ceramic components for near-term engine applications. In response to extensive input from industry, the plan is to extend the engine types which were previously supported (advanced gas turbine and low-heat-rejection diesel engines) to include near-term (5-10 years) applications in conventional automobile and diesel truck engines. To facilitate the rapid transfer of this technology to U.S. industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. A systematic approach to reducing the cost of components is envisioned.

  5. Portfolio: Ceramics.

    ERIC Educational Resources Information Center

    Hardy, Jane; And Others

    1982-01-01

    Describes eight art activities using ceramics. Elementary students created ceramic tiles to depict ancient Egyptian and medieval European art, made ceramic cookie stamps, traced bisque plates on sketch paper, constructed clay room-tableaus, and designed clay relief masks. Secondary students pit-fired ceramic pots and designed ceramic Victorian…

  6. Properties of ceramic candle filters

    SciTech Connect

    Pontius, D.H.

    1995-06-01

    The mechanical integrity of ceramic filter elements is a key issue for hot gas cleanup systems. To meet the demands of the advanced power systems, the filter components must sustain the thermal stresses of normal operations (pulse cleaning), of start-up and shut-down conditions, and of unanticipated process upsets such as excessive ash accumulation without catastrophic failure. They must also survive the various mechanical loads associated with handling and assembly, normal operation, and process upsets. For near-term filter systems, these elements must survive at operating temperatures of 1650{degrees}F for three years.

  7. Development of nondestructive evaluation techniques for high-temperature ceramic heat exchanger components. Twelfth quarterly report, July-September 1980

    SciTech Connect

    Not Available

    1980-10-01

    Detection of electric-discharge machined notches in a silicon carbide tube by an ultrasonic bore-side probe under microcomputer control has been demonstrated. Use of the reflection mode has been shown to enhance the sensitivity of flaw detection with an acoustic microscope. In this configuration, the transducer and laser-scanned coverslip are both on the tube outer surface, eliminating the need to fill the tube with water. A conceptual design is presented for inspecting tubes up to seven feet long in both through-transmission and reflection-mode configurations. A comparison of NDE techniques for ceramic butt joints showed holographic interferometry to be generally better than dye-penetrant, radiographic, or ultrasonic techniques for characterizing a crack-like inner-wall defect. Pitch-catch and pulse-echo ultrasonic techniques also indicated the presence of an anomaly in the region identified as flawed via holography, while radiographic and penetrant-testing results were ambiguous.

  8. Progress in Materials and Component Development for Advanced Lithium-ion Cells for NASA's Exploration Missions

    NASA Technical Reports Server (NTRS)

    Reid, Concha, M.; Reid, Concha M.

    2011-01-01

    Vehicles and stand-alone power systems that enable the next generation of human missions to the Moon will require energy storage systems that are safer, lighter, and more compact than current state-of-the- art (SOA) aerospace quality lithium-ion (Li-ion) batteries. NASA is developing advanced Li-ion cells to enable or enhance the power systems for the Altair Lunar Lander, Extravehicular Activities spacesuit, and rovers and portable utility pallets for Lunar Surface Systems. Advanced, high-performing materials are required to provide component-level performance that can offer the required gains at the integrated cell level. Although there is still a significant amount of work yet to be done, the present state of development activities has resulted in the synthesis of promising materials that approach the ultimate performance goals. This report on interim progress of the development efforts will elaborate on the challenges of the development activities, proposed strategies to overcome technical issues, and present performance of materials and cell components.

  9. Advanced Materials and Component Development for Lithium-Ion Cells for NASA Missions

    NASA Technical Reports Server (NTRS)

    Reid, Concha M.

    2012-01-01

    Human missions to Near Earth Objects, such as asteroids, planets, moons, liberation points, and orbiting structures, will require safe, high specific energy, high energy density batteries to provide new or extended capabilities than are possible with today s state-of-the-art aerospace batteries. The Enabling Technology Development and Demonstration Program, High Efficiency Space Power Systems Project battery development effort at the National Aeronautics and Space Administration (NASA) is continuing advanced lithium-ion cell development efforts begun under the Exploration Technology Development Program Energy Storage Project. Advanced, high-performing materials are required to provide improved performance at the component-level that contributes to performance at the integrated cell level in order to meet the performance goals for NASA s High Energy and Ultra High Energy cells. NASA s overall approach to advanced cell development and interim progress on materials performance for the High Energy and Ultra High Energy cells after approximately 1 year of development has been summarized in a previous paper. This paper will provide an update on these materials through the completion of 2 years of development. The progress of materials development, remaining challenges, and an outlook for the future of these materials in near term cell products will be discussed.

  10. Super Thin Ceramic Coatings

    NASA Video Gallery

    New technology being developed at NASA's Glenn Research Center creates super thin ceramic coatings on engine components. The Plasma Spray – Physical Vapor Deposition (PS-PVD) rig uses a powerful ...

  11. Performance of Water Recirculation Loop Maintentance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Rector, Tony; Peyton, Barbara; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  12. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  13. Advanced parametrical modelling of 24 GHz radar sensor IC packaging components

    NASA Astrophysics Data System (ADS)

    Kazemzadeh, R.; John, W.; Wellmann, J.; Bala, U. B.; Thiede, A.

    2011-08-01

    This paper deals with the development of an advanced parametrical modelling concept for packaging components of a 24 GHz radar sensor IC used in automotive driver assistance systems. For fast and efficient design of packages for system-in-package modules (SiP), a simplified model for the description of parasitic electromagnetic effects within the package is desirable, as 3-D field computation becomes inefficient due to the high density of conductive elements of the various signal paths in the package. By using lumped element models for the characterization of the conductive components, a fast indication of the design's signal-quality can be gained, but so far does not offer enough flexibility to cover the whole range of geometric arrangements of signal paths in a contemporary package. This work pursues to meet the challenge of developing a flexible and fast package modelling concept by defining parametric lumped-element models for all basic signal path components, e.g. bond wires, vias, strip lines, bumps and balls.

  14. Metallosis after Exchange of the Femoral Head and Liner following Ceramic Acetabular Liner Dissociation in Total Hip Arthroplasty with a Modular Layered Acetabular Component

    PubMed Central

    Hamada, Daisuke; Iwame, Toshiyuki; Sairyo, Koichi

    2016-01-01

    The type of bearing material that should be used in revision surgery after the failure of ceramic-on-ceramic total hip arthroplasty (THA) remains controversial. In the case of ceramic fracture, the residual ceramic particles can cause consequent metallosis when metal implants are used for revision THA. On the other hand, in the case of THA failure without ceramic fracture, revision THA with a metal femoral head provides satisfactory results. We report an unusual case of progressive osteolysis due to metallosis that developed after revision THA for ceramic liner dissociation without a liner fracture performed using a metal femoral head and polyethylene liner. The residual metal debris and abnormal pumping motion of the polyethylene liner due to the breakage of the locking system or the aspherical metal shell being abraded by the ceramic head seemed to be the cause of the progressive osteolysis. PMID:27648325

  15. Technical Needs for Prototypic Prognostic Technique Demonstration for Advanced Small Modular Reactor Passive Components

    SciTech Connect

    Meyer, Ryan M.; Coble, Jamie B.; Hirt, Evelyn H.; Ramuhalli, Pradeep; Mitchell, Mark R.; Wootan, David W.; Berglin, Eric J.; Bond, Leonard J.; Henager, Charles H.

    2013-05-17

    This report identifies a number of requirements for prognostics health management of passive systems in AdvSMRs, documents technical gaps in establishing a prototypical prognostic methodology for this purpose, and describes a preliminary research plan for addressing these technical gaps. AdvSMRs span multiple concepts; therefore a technology- and design-neutral approach is taken, with the focus being on characteristics that are likely to be common to all or several AdvSMR concepts. An evaluation of available literature is used to identify proposed concepts for AdvSMRs along with likely operational characteristics. Available operating experience of advanced reactors is used in identifying passive components that may be subject to degradation, materials likely to be used for these components, and potential modes of degradation of these components. This information helps in assessing measurement needs for PHM systems, as well as defining functional requirements of PHM systems. An assessment of current state-of-the-art approaches to measurements, sensors and instrumentation, diagnostics and prognostics is also documented. This state-of-the-art evaluation, combined with the requirements, may be used to identify technical gaps and research needs in the development, evaluation, and deployment of PHM systems for AdvSMRs. A preliminary research plan to address high-priority research needs for the deployment of PHM systems to AdvSMRs is described, with the objective being the demonstration of prototypic prognostics technology for passive components in AdvSMRs. Greater efficiency in achieving this objective can be gained through judicious selection of materials and degradation modes that are relevant to proposed AdvSMR concepts, and for which significant knowledge already exists. These selections were made based on multiple constraints including the analysis performed in this document, ready access to laboratory-scale facilities for materials testing and measurement, and

  16. High Pressure Burner Rig Testing of Advanced Environmental Barrier Coatings for Si3N4 Turbine Components

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Fox, Dennis S.; Pastel, Robert T.

    2007-01-01

    Advanced thermal and environmental barrier coatings are being developed for Si3N4 components for turbine engine propulsion applications. High pressure burner rig testing was used to evaluate the coating system performance and durability. Test results demonstrated the feasibility and durability of the coating component systems under the simulated engine environments.

  17. Pulsed Plasma Thruster (PPT) Technology: Earth Observing-1 PPT Operational and Advanced Components Being Developed

    NASA Technical Reports Server (NTRS)

    Pencil, Eric J.; Benson, Scott W.; Arrington, Lynn A.; Frus, John; Hoskins, W. Andrew; Burton, Rodney

    2003-01-01

    In 2002 the pulsed plasma thruster (PPT) mounted on the Earth Observing-1 spacecraft was operated successfully in orbit. The two-axis thruster system is fully incorporated in the attitude determination and control system and is being used to automatically counteract disturbances in the pitch axis of the spacecraft. The first tests conducted in space demonstrated the full range of PPT operation, followed by calibration of control torques from the PPT in the attitude control system. Then the spacecraft was placed in PPT control mode. To date, it has operated for about 30 hr. The PPT successfully controlled pitch momentum during wheel de-spin, solar array acceleration and deceleration during array rewind, and environmental torques in nominal operating conditions. Images collected with the Advanced Landsat Imager during PPT operation have demonstrated that there was no degradation in comparison to full momentum wheel control. In addition, other experiments have been performed to interrogate the effects of PPT operation on communication packages and light reflection from spacecraft surfaces. Future experiments will investigate the possibility of orbit-raising maneuvers, spacecraft roll, and concurrent operation with the Hyperion imager. Future applications envisioned for pulsed plasma thrusters include longer life, higher precision, multiaxis thruster configurations for three-axis attitude control systems or high-precision, formationflying systems. Advanced components, such as a "dry" mica-foil capacitor, a wear-resistant spark plug, and a multichannel power processing unit have been developed under contract with Unison Industries, General Dynamics, and C.U. Aerospace. Over the last year, evaluation tests have been conducted to determine power processing unit efficiency, atmospheric functionality, vacuum functionality, thruster performance evaluation, thermal performance, and component life.

  18. Assessment of Crack Detection in Cast Austenitic Piping Components Using Advanced Ultrasonic Methods.

    SciTech Connect

    Anderson, Michael T.; Crawford, Susan L.; Cumblidge, Stephen E.; Diaz, Aaron A.; Doctor, Steven R.

    2007-01-01

    Studies conducted at the Pacific N¬orthwest National Laboratory (PNNL) in Richland, Washington, have focused on developing and evaluating the reliability of nondestructive examination (NDE) approaches for inspecting coarse-grained, cast stainless steel reactor components. The objective of this work is to provide information to the United States Nuclear Regulatory Commission (NRC) on the utility, effec¬tiveness and limitations of ultrasonic testing (UT) inspection techniques as related to the in-service inspec¬tion of primary system piping components in pressurized water reactors (PWRs). Cast stainless steel pipe specimens were examined that contain thermal and mechanical fatigue cracks located close to the weld roots and have inside/outside surface geometrical conditions that simulate several PWR primary piping configurations. In addition, segments of vintage centrifugally cast piping were also examined to understand inherent acoustic noise and scattering due to grain structures and determine consistency of UT responses from different locations. The advanced UT methods were applied from the outside surface of these specimens using automated scanning devices and water coupling. The low-frequency ultrasonic method employed a zone-focused, multi-incident angle inspection protocol (operating at 250-450 kHz) coupled with a synthetic aperture focusing technique (SAFT) for improved signal-to-noise and advanced imaging capabilities. The phased array approach was implemented with a modified instrument operating at 500 kHz and composite volumetric images of the specimens were generated. Re¬sults from laboratory studies for assessing detection, localization and sizing effectiveness are discussed in this paper.

  19. Requirements for Prognostic Health Management of Passive Components in Advanced Small Modular Reactors

    SciTech Connect

    Meyer, Ryan M.; Coble, Jamie B.; Ramuhalli, Pradeep

    2013-08-01

    Advanced small modular reactors (aSMRs), which are based on modularization of advanced reactor concepts, may provide a longer-term alternative to traditional light-water reactors and near term small modular reactors (SMRs), which are based on integral pressurized water reactor (iPWR) concepts. aSMRs are conceived for applications in remote locations and for diverse missions that include providing process or district heating, water desalination, and hydrogen production. Several challenges exist with respect to cost-effective operations and maintenance (O&M) of aSMRs, including the impacts of aggressive operating environments and modularity, and limiting these costs and staffing needs will be essential to ensuring the economic feasibility of aSMR deployment. In this regard, prognostic health management (PHM) systems have the potential to play a vital role in supporting the deployment of aSMR systems. This paper identifies requirements and technical gaps associated with implementation of PHM systems for passive aSMR components.

  20. Flight service evaluation of an advanced composite empennage component on commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The development and flight evaluation of an advanced composite empennage component is presented. The recommended concept for the covers is graphite-epoxy hats bonded to a graphite-epoxy skin. The hat flare-out has been eliminated, instead the hat is continuous into the joint. The recommended concept for the spars is graphite-epoxy caps and a hybrid of Kevlar-49 and graphite-epoxy in the spar web. The spar cap, spar web stiffeners for attaching the ribs, and intermediate stiffeners are planned to be fabricated as a unit. Access hole in the web will be reinforced with a donut type, zero degree graphite-epoxy wound reinforcement. The miniwich design concept in the upper three ribs originally proposed is changed to a graphite-epoxy stiffened solid laminate design concept. The recommended configuration for the lower seven ribs remains as graphite-epoxy caps with aluminum cruciform diagonals. The indicated weight saving for the current advanced composite vertical fin configuration is 20.2% including a 24 lb growth allowance. The project production cost saving is approximately 1% based on a cumulative average of 250 aircraft and including only material, production labor, and quality assurance costs.

  1. High pressure ceramic joint

    DOEpatents

    Ward, Michael E.; Harkins, Bruce D.

    1993-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  2. High pressure ceramic joint

    DOEpatents

    Ward, M.E.; Harkins, B.D.

    1993-11-30

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 4 figures.

  3. Strain isolated ceramic coatings

    NASA Technical Reports Server (NTRS)

    Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

    1985-01-01

    Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

  4. Advanced manufacturing development of a composite empennage component for L-1011 aircraft

    NASA Technical Reports Server (NTRS)

    Alva, T.; Henkel, J.; Johnson, R.; Carll, B.; Jackson, A.; Mosesian, B.; Brozovic, R.; Obrien, R.; Eudaily, R.

    1982-01-01

    This is the final report of technical work conducted during the fourth phase of a multiphase program having the objective of the design, development and flight evaluation of an advanced composite empennage component manufactured in a production environment at a cost competitive with those of its metal counterpart, and at a weight savings of at least 20 percent. The empennage component selected for this program is the vertical fin box of the L-1011 aircraft. The box structure extends from the fuselage production joint to the tip rib and includes front and rear spars. During Phase 4 of the program, production quality tooling was designed and manufactured to produce three sets of covers, ribs, spars, miscellaneous parts, and subassemblies to assemble three complete ACVF units. Recurring and nonrecurring cost data were compiled and documented in the updated producibility/design to cost plan. Nondestruct inspections, quality control tests, and quality acceptance tests were performed in accordance with the quality assurance plan and the structural integrity control plan. Records were maintained to provide traceability of material and parts throughout the manufacturing development phase. It was also determined that additional tooling would not be required to support the current and projected L-1011 production rate.

  5. Viscoplastic Constitutive Theory Demonstrated for Monolithic Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Janosik, Lesley A.

    1999-01-01

    Development of accurate three-dimensional (multiaxial) inelastic stress-strain models is critical in utilizing advanced ceramics for challenging 21st century high-temperature structural applications. The current state of the art uses elastic stress fields as a basis for both subcritical crack growth and creep life prediction efforts aimed at predicting the time dependent reliability response of ceramic components subjected to elevated service temperatures. However, to successfully design components that will meet tomorrow's challenging requirements, design engineers must recognize that elastic predictions are inaccurate for these materials when subjected to high-temperature service conditions such as those encountered in advanced heat engine components. Analytical life prediction methodologies developed for advanced ceramics and other brittle materials must employ accurate constitutive models that capture the inelastic response exhibited by these materials at elevated service temperatures. A constitutive model recently developed at the NASA Lewis Research Center helps address this issue by accounting for the time-dependent (inelastic) material deformation phenomena (e.g., creep, rate sensitivity, and stress relaxation) exhibited by monolithic ceramics exposed to high-temperature service conditions. In addition, the proposed formulation is based on a threshold function that is sensitive to hydrostatic stress and allows different behavior in tension and compression, reflecting experimental observations obtained for these material systems.

  6. Structural ceramics

    SciTech Connect

    Wachtman, J.B. Jr.

    1989-01-01

    The present work discusses opportunities for application of structural ceramics in heat engines, industrial-wear parts, prosthetics and bearings; conceptual and detailed design principles for structural ceramics; the processing, consolidation, and properties of members of the SiC family of structural ceramics; and the silicon nitride and sialon families of hot-pressed, sintered, and reaction-bonded, structural ceramics. Also discussed are partially-stabilized zirconia and zirconia-toughened ceramics for structural applications, the processing methods and mechanisms of fiber-reinforcement in ceramic-matrix fiber-reinforced composites, and the tribological properties of structural ceramics.

  7. Advanced oxidation protein products are more related to metabolic syndrome components than biomarkers of lipid peroxidation.

    PubMed

    Venturini, Danielle; Simão, Andréa Name Colado; Dichi, Isaias

    2015-09-01

    Although advanced oxidation protein products (AOPPs) have been reported as the most appropriate parameter for determination of oxidative stress in patients with metabolic syndrome (MetS), a direct comparison between protein and lipid peroxidation has not been performed yet. The aim of this study was to compare protein peroxidation with lipid peroxidation measured by 2 different methodologies (tert-butyl hydroperoxide-initiated chemiluminescence and ferrous oxidation-xylenol orange assay). The hypothesis of this study was that AOPPs would be more related to MetS than to oxidative markers of lipid peroxidation. This cross-sectional study evaluated 76 patients with MetS and 20 healthy subjects. Prooxidant-antioxidant index (PAI) assessed as AOPP/total radical-trapping antioxidant parameter ratio progressively increased (P < .05) according to the number of MetS components, whereas AOPPs and total radical-trapping antioxidant parameter increased (P < .05) when 5 components were compared with 3 components. Spearman test showed a positive correlation between AOPPs and waist circumference (r = 0.318, P < .01), fasting glucose (r = 0.250, P < .05), homeostasis model assessment insulin resistance (r = 0.043, P < .01), triacylglycerol (r = 0.713, P < .0001), highly sensitive C-reactive protein (r = 0.275, P < .05), and uric acid (r = 0.356, P < .01), whereas there was an inverse correlation with high-density lipoprotein cholesterol (r = -0.399, P < .001). Prooxidant-antioxidant index demonstrated a positive correlation with waist circumference (r = 0.386, P < .01), fasting glucose (r = 0.388, P < .01), fasting insulin (r = 0.344, P < .05), homeostasis model assessment insulin resistance (r = 0.519, P < .001), triacylglycerol (r = 0.687, P < .0001), highly sensitive C-reactive protein (r = 0.278, P < .05), and uric acid (r = 0.557, P < .0001), whereas there was an inverse correlation with high-density lipoprotein cholesterol (r = -0.480, P < .0001). In conclusion, protein

  8. Ceramic applications in turbine engines

    NASA Technical Reports Server (NTRS)

    Helms, H. E.; Heitman, P. W.; Lindgren, L. C.; Thrasher, S. R.

    1984-01-01

    The application of ceramic components to demonstrate improved cycle efficiency by raising the operating temperature of the existing Allison IGI 404 vehicular gas turbine engine is discussed. This effort was called the Ceramic Applications in Turbine Engines (CATE) program and has successfully demonstrated ceramic components. Among these components are two design configurations featuring stationary and rotating caramic components in the IGT 404 engine. A complete discussion of all phases of the program, design, materials development, fabrication of ceramic components, and testing-including rig, engine, and vehicle demonstation test are presented. During the CATE program, a ceramic technology base was established that is now being applied to automotive and other gas turbine engine programs. This technology base is outlined and also provides a description of the CATE program accomplishments.

  9. IMPROVEMENT OF WEAR COMPONENT'S PERFORMANCE BY UTILIZING ADVANCED MATERIALS AND NEW MANUFACTURING TECHNOLOGIES: CASTCON PROCESS FOR MINING APPLICATIONS

    SciTech Connect

    Xiaodi Huang; Richard Gertsch

    2002-08-27

    The project has seen quite a bit of activity in this quarter, highlighted by the fabrication of a bit insert for field testing. In addition: (1) Several alternative process techniques were attempted to prevent bloating, cracking and delamination of FM material that occurs during binder burnout. The approaches included fabrication of FM material by three pass extrusion and warm isostatic pressing of green material, slow and confined burnouts as well as, burnout of thin plate instead of rod stock. Happily, a confined burnout followed by HIPing, produced FM button inserts without bloating or delamination. (2) Four rock bit inserts were produced from FM material and are ready for use on blast hole bits in the field. (3) Six of the project participants from Michigan Technological University, Advanced Ceramic Manufacturing, and The Robbins Group visited the Superior Rock Bit Company in Minnesota and planned the field test of FM inserts.

  10. CARES/Life Software for Designing More Reliable Ceramic Parts

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Powers, Lynn M.; Baker, Eric H.

    1997-01-01

    Products made from advanced ceramics show great promise for revolutionizing aerospace and terrestrial propulsion, and power generation. However, ceramic components are difficult to design because brittle materials in general have widely varying strength values. The CAPES/Life software eases this task by providing a tool to optimize the design and manufacture of brittle material components using probabilistic reliability analysis techniques. Probabilistic component design involves predicting the probability of failure for a thermomechanically loaded component from specimen rupture data. Typically, these experiments are performed using many simple geometry flexural or tensile test specimens. A static, dynamic, or cyclic load is applied to each specimen until fracture. Statistical strength and SCG (fatigue) parameters are then determined from these data. Using these parameters and the results obtained from a finite element analysis, the time-dependent reliability for a complex component geometry and loading is then predicted. Appropriate design changes are made until an acceptable probability of failure has been reached.

  11. Batch compositions for cordierite ceramics

    DOEpatents

    Hickman, David L.

    1994-07-26

    Ceramic products consisting principally of cordierite and a method for making them are provided, the method employing batches comprising a mineral component and a chemical component, the mineral component comprising clay and talc and the chemical component consisting essentially of a combination of the powdered oxides, hydroxides, or hydrous oxides of magnesium, aluminum and silicon. Ceramics made by extrusion and firing of the batches can exhibit low porosity, high strength and low thermal expansion coefficients.

  12. Development and application of NDE methods for monolithic and continuous fiber ceramic matrix composites.

    SciTech Connect

    Ellingson, W. A.

    1999-05-21

    Monolithic structural ceramics and continuous fiber ceramic matrix composites (CMCs) are being developed for application in many thermally and chemically aggressive environments where structural reliability is paramount. We have recently developed advanced nondestructive evaluation (NDE) methods that can detect distributed ''defects'' such as density gradients and machining-induced damage in monolithic materials, as well as delamination, porosity, and throughwall cracks, in CMC materials. These advanced NDE methods utilize (a) high-resolution, high-sensitivity thermal imaging; (b) high-resolution X-ray imaging; (c) laser-based elastic optical scattering; (d) acoustic resonance; (e) air-coupled ultrasonic methods; and (f) high-sensitivity fluorescent penetrant technology. This paper discusses the development and application of these NDE methods relative to ceramic processing and ceramic components used in large-scale industrial gas turbines and hot gas filters for gas stream particulate cleanup.

  13. Proof test of hybrid shrink fits with ceramic hub

    NASA Astrophysics Data System (ADS)

    Wagner, M.; Binz, H.

    2011-10-01

    Advanced ceramic machine components are required in many applications because of their specific material properties like high hardness, resistance to chemicals, corrosion and wear, low specific weight etc. The most suitable shaft-hub connection to ceramics is an interference fit assembly because it is free of geometrical notches and transmission of forces takes place in a large area. Such a shrink fit is rated for endurance strength when the stress intensity factor is below the specific value KI0 where no crack growth occurs. The total component suddenly fails, when the stress intensity factor exceeds the KIC value. The load to the press fit during the joining process, caused by the interference of the assembly, could be regulated by ambient conditions. In case of undetected material defects or microcracks in the ceramic and if the stress intensity is below KIC, the ceramic will not fail but a crack could grow. Thus, the joining process only seems to be a proof test. When the load during operation leads to a stress intensity that remains higher than KI0 the crack grows until the whole ceramic component fails. This effect was verified in tests at the Institute for Engineering Design and Industrial Design.

  14. A Viscoplastic Constitutive Theory for Monolithic Ceramic Materials. Series 1

    NASA Technical Reports Server (NTRS)

    Janosik, Lesley A.; Duffy, Stephen F.

    1997-01-01

    With increasing use of ceramic materials in high temperature structural applications such as advanced heat engine components, the need arises to accurately predict thermomechanical behavior. This paper, which is the first of two in a series, will focus on inelastic deformation behavior associated with these service conditions by providing an overview of a viscoplastic constitutive model that accounts for time-dependent hereditary material deformation (e.g., creep, stress relaxation, etc.) in monolithic structural ceramics. Early work in the field of metal plasticity indicated that inelastic deformations are essentially unaffected by hydrostatic stress. This is not the case, however, for ceramic-based material systems, unless the ceramic is fully dense. The theory presented here allows for fully dense material behavior as a limiting case. In addition, ceramic materials exhibit different time-dependent behavior in tension and compression. Thus, inelastic deformation models for ceramics must be constructed in a fashion that admits both sensitivity to hydrostatic stress and differing behavior in tension and compression. A number of constitutive theories for materials that exhibit sensitivity to the hydrostatic component of stress have been proposed that characterize deformation using time-independent classical plasticity as a foundation. However, none of these theories allow different behavior in tension and compression. In addition, these theories are somewhat lacking in that they are unable to capture creep, relaxation, and rate-sensitive phenomena exhibited by ceramic materials at high temperature. When subjected to elevated service temperatures, ceramic materials exhibit complex thermomechanical behavior that is inherently time-dependent, and hereditary in the sense that current behavior depends not only on current conditions, but also on thermo-mechanical history. The objective of this work is to present the formulation of a macroscopic continuum theory that

  15. Proton irradiation effects on advanced digital and microwave III-V components

    SciTech Connect

    Hash, G.L.; Schwank, J.R.; Shaneyfelt, M.R.; Sandoval, C.E.; Connors, M.P.; Sheridan, T.J.; Sexton, F.W.; Slayton, E.M.; Heise, J.A.; Foster, C.

    1994-09-01

    A wide range of advanced III-V components suitable for use in high-speed satellite communication systems were evaluated for displacement damage and single-event effects in high-energy, high-fluence proton environments. Transistors and integrated circuits (both digital and MMIC) were irradiated with protons at energies from 41 to 197 MeV and at fluences from 10{sup 10} to 2 {times} 10{sup 14} protons/cm{sup 2}. Large soft-error rates were measured for digital GaAs MESFET (3 {times} 10{sup {minus}5} errors/bit-day) and heterojunction bipolar circuits (10{sup {minus}5} errors/bit-day). No transient signals were detected from MMIC circuits. The largest degradation in transistor response caused by displacement damage was observed for 1.0-{mu}m depletion- and enhancement-mode MESFET transistors. Shorter gate length MESFET transistors and HEMT transistors exhibited less displacement-induced damage. These results show that memory-intensive GaAs digital circuits may result in significant system degradation due to single-event upset in natural and man-made space environments. However, displacement damage effects should not be a limiting factor for fluence levels up to 10{sup 14} protons/cm{sup 2} [equivalent to total doses in excess of 10 Mrad(GaAs)].

  16. Analysis of hot forming of a sheet metal component made of advanced high strength steel

    NASA Astrophysics Data System (ADS)

    Demirkaya, Sinem; Darendeliler, Haluk; Gökler, Mustafa İlhan; Ayhaner, Murat

    2013-05-01

    To provide reduction in weight while maintaining crashworthiness and to decrease the fuel consumption of vehicles, thinner components made of Advanced High Strength Steels (AHSS) are being increasingly used in automotive industry. However, AHSS cannot be formed easily at the room temperature (i.e. cold forming). The alternative process involves heating, hot forming and subsequent quenching. A-pillar upper reinforcement of a vehicle is currently being produced by cold forming of DP600 steel sheet with a thickness of 1.8 mm. In this study, the possible decrease in the thickness of this particular part by using 22MnB5 as appropriate AHSS material and applying this alternative process has been studied. The proposed process involves deep drawing, trimming, heating, sizing, cooling and piercing operations. Both the current production process and the proposed process are analyzed by the finite element method. The die geometry, blank holding forces and the design of the cooling channels for the cooling process are determined numerically. It is shown that the particular part made of 22MnB5 steel sheet with a thickness of 1.2 mm can be successfully produced by applying the proposed process sequence and can be used without sacrificing the crashworthiness. With the use of the 22MnB5 steel with a thickness of 1.2 mm instead of DP600 sheet metal with a thickness of 1.8 mm, the weight is reduced by approximately 33%.

  17. Ceramic Stereolithography: Additive Manufacturing for Ceramics by Photopolymerization

    NASA Astrophysics Data System (ADS)

    Halloran, John W.

    2016-07-01

    Ceramic stereolithography and related additive manufacturing methods involving photopolymerization of ceramic powder suspensions are reviewed in terms of the capabilities of current devices. The practical fundamentals of the cure depth, cure width, and cure profile are related to the optical properties of the monomer, ceramic, and photo-active components. Postpolymerization steps, including harvesting and cleaning the objects, binder burnout, and sintering, are discussed and compared with conventional methods. The prospects for practical manufacturing are discussed.

  18. Robocasting of Ceramics and Composites Using Fine Particle Suspensions

    SciTech Connect

    CESARANO III,JOSEPH

    1999-10-28

    Solid freeform fabrication is the near-net-shape manufacturing of components by sequentially stacking thin layers of material until complicated three dimensional shapes are produced. The operation is computer controlled and requires no molds. This exciting new field of technology provides engineers with the ability to rapidly produce prototype parts directly from CAD drawings and oftentimes little or no machining is necessary after fabrication. Techniques for freeform fabrication with several types of plastics and metals are already quite advanced and maybe reviewed in references 1 and 2. Very complicated plastic models can be fabricated by stereolithography, selective laser sintering, fused deposition modeling, or three-dimensional ink jet printing. Metals may be freeformed by the LENS{trademark} technique and porous ceramic bodies by three dimensional printing into a porous powder bed. However, methods for freeform fabrication that utilize particulate slurries to build dense ceramics and composites are not as well developed. The techniques that are being developed for the freeform fabrication of dense structural ceramics primarily revolve around the sequential layering of ceramic loaded polymers or waxes. Laminated Object Manufacturing and CAM-LEM processing use controlled stacking and laser cutting of ceramic tapes [2,3]. Similar to fused deposition modeling, ceramic loaded polymer/wax filaments are being used for the fused deposition of ceramics [2,4]. Extrusion freeform fabrication uses high pressure extrusion to deposit layers of ceramic loaded polymer/wax systems[1]. Modified stereolithographic techniques are also being developed using ceramic loaded ultraviolet curable resins [2]. Pre-sintered parts made with any of these techniques typically have 40-55 vol.% polymeric binder. In this regard, these techniques are analogous to powder injection molding of ceramics. Very long and complicated burnout heat treatments are necessary to produce a dense ceramic

  19. Materials support for the development of high temperature advanced furnaces (HITAF): A comparison of selected mechanical properties for three SiC-based ceramics

    SciTech Connect

    Breder, K.; Tennery, V.J.

    1994-09-01

    Purpose of this project is to compare structural ceramic materials proposed for use in the air heater of a coal fired high temperature advanced furnace (HITAF) for power generation. The work will provide necessary initial strength and statistical material parameters for design of a prototype system. Two teams are currently funded by Pittsburgh Energy Technology Center (PETC) under the Combustion 2000 program to develop such a system. One team is led by the United Technologies Research Corporation, and consists of UTC Turbo Power and Marine Division, Bechtel, Oak Ridge National Laboratory (ORNL) and a Joint Venture of Physical Sciences Inc. (PSI) Technologies, Reaction Engineering International (REI) and University of North Dakota Energy & Environmental Research Center (UNDEERC); the other team is led by Foster Wheeler Development Corporation, and members are AiResearch Division of AlliedSignal Aerospace Systems & Equipment, Research Cottrell, TRW, General Electric and Bechtel.

  20. Silicon carbide ceramic production

    NASA Technical Reports Server (NTRS)

    Suzuki, K.; Shinohara, N.

    1984-01-01

    A method to produce sintered silicon carbide ceramics in which powdery carbonaceous components with a dispersant are mixed with silicon carbide powder, shaped as required with or without drying, and fired in nonoxidation atmosphere is described. Carbon black is used as the carbonaceous component.

  1. On Ceramics.

    ERIC Educational Resources Information Center

    School Arts, 1982

    1982-01-01

    Presents four ceramics activities for secondary-level art classes. Included are directions for primitive kiln construction and glaze making. Two ceramics design activities are described in which students make bizarrely-shaped lidded jars, feet, and footwear. (AM)

  2. Determination of metal impurities in advanced lead zirconate titanate ceramics by axial view mode inductively coupled plasma optical emission spectrometry.

    PubMed

    Villanueva Tagle, M E; Larrea Marín, M T; Martin Gavilán, O; Durruthy Rodríguez, M D; Calderón Piñar, F; Pomares Alfonso, M S

    2012-05-30

    An inductively coupled plasma optical emission spectrometry quantification method for the determination of Al, Ca, Cr Cu, Fe, Mn, Mg, Ni, Zn, Ba, K, In and Co in lead zirconate-titanate (PZT) ceramics, modified with strontium and chromium, was developed. Total digestion of ceramics was achieved with a HNO(3), H(2)O(2) and HF (ac) mixture by using a microwave furnace. The sensitivity of the net signal intensity respect to radiofrequency power (P) and nebulizer argon flow (F(N)) variations was strongly dependent of the total excitation energy of line (TEE). For lines with TEE near metastable atoms and ions of argon, an increment of the sensitivities to P and F(N) variation was observed. At robust plasma conditions the matrix effect was reduced for all matrices and analytes considered. The precision of analysis ranged from 3 to 13%, whereas the analytes recoveries in the spiked samples varied, mostly, from 90 to 110%. The detection limits of studied elements were from 0.004 to 10 mg kg(-1).

  3. Ceramic Material.

    DTIC Science & Technology

    1990-05-02

    A ceramic material which is (1) ceramics based on monoclinic BaO.Al2O3.2SiO2; (2) ceramics based on monoclinic SrO.Al2O3.2SiO2; or (3) ceramics based on monoclinic solid solution of BaO.Al2O3.2SiO2 and SrO.Al2O3.2SiO2.

  4. Structural Ceramics

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This publication is a compilation of abstracts and slides of papers presented at the NASA Lewis Structural Ceramics Workshop. Collectively, these papers depict the scope of NASA Lewis' structural ceramics program. The technical areas include monolithic SiC and Si3N4 development, ceramic matrix composites, tribology, design methodology, nondestructive evaluation (NDE), fracture mechanics, and corrosion.

  5. A Proposal for an Experiment in Space: Laser Welding of Ceramics in Microgravity

    NASA Astrophysics Data System (ADS)

    Favuzza, M.; Camiolo, F.

    2002-01-01

    Ceramics are brittle because of their strong covalent or ionic bonds. Brittleness is not the only limitation of ceramics, also the presence of generally up to 20% porosity and the presence of microcracks (c.a. 25%) make ceramics rarely used for advanced applications. Often metals and composites are preferred for certain applications because of its higher fracture toughness. Nevertheless, there are also many advantages in using ceramics if compared to metals and composites such as high hardness, strength retention over a broad temperature range, wear and acid resistance, thermal shock resistance, possibility to be ground with a very smooth surface to high tolerances and low cost. Hence, during the last years, the ceramics market for engineering applications is to be considered in expansion. By keeping into consideration that today a values of KIC25 MPa m1/2 can be attained for some types of ceramics, one of the main factors that influences the utilisation of ceramics for engineering structures is the strong difficulty in joining its together. Most of the modern "Advanced Ceramics" are, in fact, highly-reactive so that its manufacturing and sintering procedures must be carried out only under controlled atmosphere. All that make the possibility to join advanced ceramics by any heat treatment basically impossible under normal conditions. Today, uses of that kind of ceramics are generally restricted to advanced small structural shapes. Starting from the consideration that a future possibility to join ceramics with a safe joint would be really important for structural applications especially where high wear and acid resistance is necessary, the aim of this paper is to show as, according to our theory, a first step of laser welding of reactive ceramics is possible under microgravity and oxigen deficiency conditions. It is enough to think about a satellite or a part of the ISS made from absolutely fire, chemical and wear proof ceramic parts assembled directly on space by

  6. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, T.D.

    1996-07-23

    Ceramic materials are disclosed which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200--550 C or organic salt (including SO{sub 2} and SO{sub 2}Cl{sub 2}) at temperatures of 25--200 C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components. 1 fig.

  7. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, Thomas D.

    1996-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  8. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, Thomas D.

    1995-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  9. Role of nickel ion coordination on spectroscopic properties of multi-component CaF2-Bi2O3-P2O5-B2O3 glass-ceramics

    NASA Astrophysics Data System (ADS)

    Suresh, S.; Narendrudu, T.; Kumar, A. Suneel; Rao, M. V. Sambasiva; Ram, G. Chinna; Rao, D. Krishna

    2016-10-01

    Multi-component CaF2-Bi2O3-P2O5-B2O3 glasses doped with different concentrations of NiO were crystallized through heat treatment. The prepared glass ceramic samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), differential thermal analysis (DTA) as well as conventional spectroscopic studies viz., optical absorption, Fourier transform infrared (FTIR) and Raman. The XRD and SEM studies have indicated that the samples contain well defined and randomly distributed grains of different crystalline phases. The optical absorption studies together with FTIR and Raman measurements indicated the gradual transformation of nickel ions from tetrahedral sites to octahedral sites (lasing sites) as the concentration of NiO is increased beyond 1.5 mol%. All these investigations have indicated that the growing degree of disorder in the glass ceramic network at higher concentrations of NiO. Glass ceramics doped with NiO beyond 1.5 mol% appear to be suitable for getting laser emission due to 3T2(F) → 3A2(F) transition in NIR region. These glass-ceramics can be expected as an amplification medium for tunable lasers and broadband optical amplifiers for wavelength division multiplexing transmission system.

  10. Uses of ceramics in microelectronics: A survey

    NASA Technical Reports Server (NTRS)

    Bratschun, W. R.; Mountvala, A. J.; Pincus, A. G.

    1971-01-01

    The properties and behavior of ceramic materials used in components for electronic circuitry are examined to appraise the present and future directions for microelectronics, and to suggest further product development, and how innovations may be useful in other technologies. Ceramic and glass insulators, resistors, capacitors, and the use of ceramics and glasses in microcircuitry are discussed along with technology transfer to nonaerospace uses.

  11. Self-Assembling, Flexible, Pre-Ceramic Composite Preforms

    NASA Technical Reports Server (NTRS)

    Jaskowiak, Martha H.; Eckel, Andrew J.; Gorican, Daniel

    2009-01-01

    surrounding structures can be avoided in the collapsed state. The larger exit plane leads to an increase in expansion area ratio, which has the potential to increase thrust and overall rocket performance. In general, the use of advanced ceramic materials can lead to improved engine and vehicle performance. The ceramics can run hotter, so less cooling is required. Fuel to coolant ratios can be balanced more readily to reduce weight. Engine efficiency can also be increased with hotter combustion and exhaust temperatures. In addition, the ceramic composites themselves can reduce the component weight by as much as 50 percent, which can translate into greater payload for the vehicle

  12. Advanced methodology for measuring the extensive elastic compliance and mechanical loss directly in k31 mode piezoelectric ceramic plates

    NASA Astrophysics Data System (ADS)

    Majzoubi, Maryam; Shekhani, Husain N.; Bansal, Anushka; Hennig, Eberhard; Scholehwar, Timo; Uchino, Kenji

    2016-12-01

    Dielectric, elastic, and piezoelectric constants, and their corresponding losses are defined under constant conditions of two categories; namely, intensive (i.e., E, electric field or T, stress), and extensive (i.e., D, dielectric displacement or x, strain) ones. So far, only the intensive parameters and losses could be measured directly in a k31 mode sample. Their corresponding extensive parameters could be calculated indirectly using the coupling factor and "K" matrix. However, the extensive loss parameters, calculated through this indirect method, could have large uncertainty, due to the error propagation in calculation. In order to overcome this issue, extensive losses should be measured separately from the measurable intensive ones in lead-zirconate-titanate (PZT) k31 mode rectangular plate ceramics. We propose a new mechanical-excitation methodology, using a non-destructive testing approach by means of a partial electrode configuration, instead of the conventional full electrode configuration. For this purpose, a non-electrode sample was prepared, where the electrode covered only 10% of the top and bottom surfaces at the center to actuate the whole sample, and also monitor the responding vibration. The admittance spectrum of this sample, corresponds to PZT properties under dielectric displacement D constant condition. Furthermore, ceramics with partial-electrodes were also prepared to create short and open circuit boundary conditions, attributing to resonance and anti-resonance modes. In the proposed way, we were able to measure both intensive and extensive elastic compliances and mechanical losses directly for the first time. The accuracy of this new method is compared with the conventional measurements by use of indirect calculations. The preliminary results (by neglecting the 10% actuator part difference at this point) were obtained, which were in good agreements (less than 3% difference) with the previous indirect method.

  13. Durability of ceramic filters

    SciTech Connect

    Alvin, M.A.; Tressler, R.E.; Lippert, T.E.; Diaz, E.S.; Smeltzer, E.E.

    1994-10-01

    The objectives of this program are to identify the potential long-term thermal/chemical effects that advanced coal-based power generating systems have on the stability of porous ceramic filter materials, as well as to assess the influence of these effects on filter operating performance and life.

  14. Current status of environmental barrier coatings for Si-Based ceramics

    NASA Technical Reports Server (NTRS)

    Lee, K. N.

    2000-01-01

    Silicon-based ceramics are the leading candidates for high temperature structural components in next generation gas turbine engines. One key drawback of silicon-based ceramics for such an application is volatilization of the protective silica scale in water vapor and the resulting rapid ceramic recession. Therefore, the realization of Si-based ceramics components in advanced gas turbine engines depends on the development of protection schemes from water vapor attack. Currently, plasma-sprayed external environmental barrier coatings (EBCs) arc the most promising approach. In the late 1980s and early 1990s a wide range of refractory oxide materials were tested as coatings on Si-based ceramics to provide protection from hot corrosion. After the discovery of silica volatilization in water vapor in the early 1990s, the focus of EBC development research has been shifted towards the protection from water vapor attack. Experience learned form the earlier coating developmental effort provided the foundation upon which more complex and advanced EBC coatings have been developed. This paper will discuss the brief history and the current status of EBC development for Si-based ceramics with the main focus on water vapor protection.

  15. Specialized data analysis for the Space Shuttle Main Engine and diagnostic evaluation of advanced propulsion system components

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Marshall Space Flight Center is responsible for the development and management of advanced launch vehicle propulsion systems, including the Space Shuttle Main Engine (SSME), which is presently operational, and the Space Transportation Main Engine (STME) under development. The SSME's provide high performance within stringent constraints on size, weight, and reliability. Based on operational experience, continuous design improvement is in progress to enhance system durability and reliability. Specialized data analysis and interpretation is required in support of SSME and advanced propulsion system diagnostic evaluations. Comprehensive evaluation of the dynamic measurements obtained from test and flight operations is necessary to provide timely assessment of the vibrational characteristics indicating the operational status of turbomachinery and other critical engine components. Efficient performance of this effort is critical due to the significant impact of dynamic evaluation results on ground test and launch schedules, and requires direct familiarity with SSME and derivative systems, test data acquisition, and diagnostic software. Detailed analysis and evaluation of dynamic measurements obtained during SSME and advanced system ground test and flight operations was performed including analytical/statistical assessment of component dynamic behavior, and the development and implementation of analytical/statistical models to efficiently define nominal component dynamic characteristics, detect anomalous behavior, and assess machinery operational condition. In addition, the SSME and J-2 data will be applied to develop vibroacoustic environments for advanced propulsion system components, as required. This study will provide timely assessment of engine component operational status, identify probable causes of malfunction, and indicate feasible engineering solutions. This contract will be performed through accomplishment of negotiated task orders.

  16. Ceramic combustor mounting

    DOEpatents

    Hoffman, Melvin G.; Janneck, Frank W.

    1982-01-01

    A combustor for a gas turbine engine includes a metal engine block including a wall portion defining a housing for a combustor having ceramic liner components. A ceramic outlet duct is supported by a compliant seal on the metal block and a reaction chamber liner is stacked thereon and partly closed at one end by a ceramic bypass swirl plate which is spring loaded by a plurality of circumferentially spaced, spring loaded guide rods and wherein each of the guide rods has one end thereof directed exteriorly of a metal cover plate on the engine block to react against externally located biasing springs cooled by ambient air and wherein the rod spring support arrangement maintains the stacked ceramic components together so that a normal force is maintained on the seal between the outlet duct and the engine block under all operating conditions. The support arrangement also is operative to accommodate a substantial difference in thermal expansion between the ceramic liner components of the combustor and the metal material of the engine block.

  17. Development and testing of CMC components for automotive gas turbine engines

    NASA Technical Reports Server (NTRS)

    Khandelwal, Pramod K.

    1991-01-01

    Ceramic matrix composite (CMC) materials are currently being developed and evaluated for advanced gas turbine engine components because of their high specific strength and resistance to catastrophic failure. Components with 2D and 3D composite architectures have been successfully designed and fabricated. This is an overview of the test results for a backplate, combustor, and a rotor.

  18. Ceramic technology report. Semi-annual progress report, April 1994--September 1994

    SciTech Connect

    Johnson, D.R.

    1995-06-01

    The Ceramic Technology Project was originally developed by the Department of Energy`s Office of Transportation Systems (OTS) in Energy Efficiency and Renewable Energy. This project, part of the OTS`s Materials Development Program, was developed to meet the ceramic technology requirements of the OTS`s automotive technology programs. Significant accomplishments in fabricating ceramic components for the Department of Energy (DOE), National Aeronautics and Space Administration (NASA), and Department of Defense (DoD) advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. In response to extensive input from industry, the plan is to extend the engine types which were previously supported (advanced gas turbine and low-heat-rejection diesel engines) to include near-term (5-10 years) applications in conventional automobile and diesel truck engines. To facilitate the rapid transfer of this technology to U.S. industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. A systematic approach to reducing the cost of components is envisioned. The work elements are as follows: economic cost modeling, ceramic machining, powder synthesis, alternative forming and densification processes, yield improvement, system design studies, standards development, low-expansion ceramics, and testing and data base development.

  19. Advanced Turbine Technology Applications Project (ATTAP)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This report is the fifth in a series of Annual Technical Summary Reports for the Advanced Turbine Technology Applications Project (ATTAP), sponsored by the U.S. Department of Energy (DOE). The report was prepared by Garrett Auxiliary Power Division (GAPD), a unit of Allied-Signal Aerospace Company, a unit of Allied Signal, Inc. The report includes information provided by Garrett Ceramic Components, and the Norton Advanced Ceramics Company, (formerly Norton/TRW Ceramics), subcontractors to GAPD on the ATTAP. This report covers plans and progress on ceramics development for commercial automotive applications over the period 1 Jan. through 31 Dec. 1992. Project effort conducted under this contract is part of the DOE Gas Turbine Highway Vehicle System program. This program is directed to provide the U.S. automotive industry the high-risk, long-range technology necessary to produce gas turbine engines for automobiles with reduced fuel consumption, reduced environmental impact, and a decreased reliance on scarce materials and resources. The program is oriented toward developing the high-risk technology of ceramic structural component design and fabrication, such that industry can carry this technology forward to production in the 1990's. The ATTAP test bed engine, carried over from the previous AGT101 project, is being used for verification testing of the durability of next generation ceramic components, and their suitability for service at Reference Powertrain Design conditions. This document reports the technical effort conducted by GAPD and the ATTAP subcontractors during the fifth year of the project. Topics covered include ceramic processing definition and refinement, design improvements to the ATTAP test bed engine and test rigs, and the methodology development of ceramic impact and fracture mechanisms. Appendices include reports by ATTAP subcontractors in the development of silicon nitride materials and processes.

  20. Ceramic Matrix Composites (CMC) Life Prediction Development

    NASA Technical Reports Server (NTRS)

    Levine, Stanley R.; Verrilli, Michael J.; Thomas, David J.; Halbig, Michael C.; Calomino, Anthony M.; Ellis, John R.; Opila, Elizabeth J.

    1990-01-01

    Advanced launch systems will very likely incorporate fiber reinforced ceramic matrix composites (CMC) in critical propulsion and airframe components. The use of CMC will save weight, increase operating margin, safety and performance, and improve reuse capability. For reusable and single mission use, accurate life prediction is critical to success. The tools to accomplish this are immature and not oriented toward the behavior of carbon fiber reinforced silicon carbide (C/SiC), the primary system of interest for many applications. This paper describes an approach and progress made to satisfy the need to develop an integrated life prediction system that addresses mechanical durability and environmental degradation.

  1. Advances in high temperature components for AMTEC (Alkali Metal Thermal-to-Electric Converter)

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Jeffries-Nakamura, B.; Underwood, M. L.; Ryan, M. A.; O'Connor, D.; Kikkert, S.

    1991-01-01

    The basic performance of Alkali Metal Thermal-to-Electric Converter (AMTEC) cells is well understood, and quantitative modeling of the electrode performance has been carried out. Tests have been carried out to evaluate the high temperature performance of critical AMTEC components. Progress made in understanding the relative performance of AMTEC components, such as electrodes, electrolytes, working fluids, and seals, as device operating temperature is varied is discussed. Most metallic components are especially subject to corrosion in hot liquid alkali metals containing dissolved oxides. Stability issues of AMTEC components may be addressed by life testing, accelerated testing, and modeling based on known kinetic and thermochemical data.

  2. Identifying components of advanced-level clinical nutrition practice: a Delphi study.

    PubMed

    Brody, Rebecca A; Byham-Gray, Laura; Touger-Decker, Riva; Passannante, Marian R; O'Sullivan Maillet, Julie

    2012-06-01

    The dietetics profession lacks a comprehensive definition of advanced-level practice. Using a three-round Delphi study with mailed surveys, expert consensus on four dimensions of advanced-level practice that define advanced practice registered dietitians (RDs) in clinical nutrition was explored. Purposive sampling identified 117 RDs who met advanced-level practice criteria. In round 1, experts rated the essentiality of statements on a 7-point ordinal scale and generated open-ended practice activity statements regarding the following four dimensions of advanced-level practice: professional knowledge, abilities and skills, approaches to practice, roles and relationships, and practice behaviors. Median ratings of 1.0 to 3.0 were defined as essential, 4.0 was neutral, and 5.0 to 7.0 were nonessential. In rounds 2 and 3, experts re-rated statements not reaching consensus by evaluating their previous responses, group median rating, and comments. Consensus was reached when the interquartile range of responses to a statement was ≤2.0. Eighty-five experts enrolled (72.6%); 76 (89.4%) completed all rounds. In total, 233 statements were rated, with 100% achieving consensus; 211 (90.6%) were essential to advanced practice RD clinical practice. Having a master's degree; completing an advanced practice residency; research coursework; and advanced continuing education were essential, as were having 8 years of experience; clinical nutrition knowledge/expertise; specialization; participation in research activities; and skills in technology and communication. Highly essential approaches to practice were systematic yet adaptable and used critical thinking and intuition and highly essential values encompassed professional growth and service to patients. Roles emphasized patient care and leadership. Essential practice activities within the nutrition care process included provision of complex patient-centered nutrition care using application of advanced knowledge/expertise and

  3. Nuclear Magnetic Resonance Used to Quantify the Effect of Pyrolysis Conditions on the Oxidative Stability of Silicon Oxycarbide Ceramics

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This work was undertaken in support of the Low Cost Ceramic Composite Virtual Company, (LC^3), whose members include Northrop Grumman Corporation, AlliedSignal Inc., and Allison Advanced Development Company. LC^3 is a cost-shared effort funded by the Advanced Research Projects Agency (ARPA) and the LC^3 participants to develop a low-cost fabrication methodology for manufacturing ceramic matrix composite structural components. The program, which is being administered by the U.S. Air Force Wright Laboratory Materials Directorate, is focused on demonstrating a ceramic matrix composite turbine seal for a regional aircraft engine. This part is to be fabricated by resin transfer molding of a siloxane polymer into a fiber preform that will be transformed into a ceramic by pyrolytic conversion.

  4. Ceramic Matrix Composites for Rotorcraft Engines

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.

    2011-01-01

    Ceramic matrix composite (CMC) components are being developed for turbine engine applications. Compared to metallic components, the CMC components offer benefits of higher temperature capability and less cooling requirements which correlates to improved efficiency and reduced emissions. This presentation discusses a technology develop effort for overcoming challenges in fabricating a CMC vane for the high pressure turbine. The areas of technology development include small component fabrication, ceramic joining and integration, material and component testing and characterization, and design and analysis of concept components.

  5. XUV synchrotron optical components for the Advanced Light Source: Summary of the requirements and the developmental program

    SciTech Connect

    McKinney, W.; Irick, S.; Lunt, D.

    1992-07-01

    We give a brief summary of the requirements for water cooled optical components for the Advanced Light Source (ALS), a third generation synchrotron radiation source under construction at Lawrence Berkeley Laboratory (LBL). Materials choices, surface figure and smoothness specifications, and metrology systems for measuring the plated metal surfaces are discussed. Results from a finished water cooled copper alloy mirror will be used to demonstrate the state of the art in optical metrology with the Takacs Long Trace Profiler (LTP II).

  6. Development and setting of a new system for advanced rheocast components

    SciTech Connect

    Rosso, Mario; Peter, I.; Calosso, F.

    2011-05-04

    This paper presents an overview of alternative methods of production of enhanced performance Al-based alloys components for critical areas. In particular, a new rheocasting system, suitable for the manufacturing of high performance industrial components has been considered. The aforementioned method allows obtaining component quickly and results a more convenient process, from economical point of view than other innovative processes. Two series of components have been produced with A356 and A357 alloys, then have been heat treated using T5 and T6 treatments. On polished transverse sections of samples the microstructure of the alloy has been observed. Their soundness has been previously certified by non destructive tests. Samples for tensile and three point bending tests have been machined directly from the produced components. On the fractured samples, fracture surface analysis has been performed in order to analyze and evaluate the influence of the process and of the alloy on the fracture behaviour.

  7. Development and setting of a new system for advanced rheocast components

    NASA Astrophysics Data System (ADS)

    Rosso, Mario; Peter, I.; Calosso, F.

    2011-05-01

    This paper presents an overview of alternative methods of production of enhanced performance Al-based alloys components for critical areas. In particular, a new rheocasting system, suitable for the manufacturing of high performance industrial components has been considered. The aforementioned method allows obtaining component quickly and results a more convenient process, from economical point of view than other innovative processes. Two series of components have been produced with A356 and A357 alloys, then have been heat treated using T5 and T6 treatments. On polished transverse sections of samples the microstructure of the alloy has been observed. Their soundness has been previously certified by non destructive tests. Samples for tensile and three point bending tests have been machined directly from the produced components. On the fractured samples, fracture surface analysis has been performed in order to analyze and evaluate the influence of the process and of the alloy on the fracture behaviour.

  8. FY2015 ceramic fuels development annual highlights

    SciTech Connect

    Mcclellan, Kenneth James

    2015-09-22

    Key challenges for the Advanced Fuels Campaign are the development of fuel technologies to enable major increases in fuel performance (safety, reliability, power and burnup) beyond current technologies, and development of characterization methods and predictive fuel performance models to enable more efficient development and licensing of advanced fuels. Ceramic fuel development activities for fiscal year 2015 fell within the areas of 1) National and International Technical Integration, 2) Advanced Accident Tolerant Ceramic Fuel Development, 3) Advanced Techniques and Reference Materials Development, and 4) Fabrication of Enriched Ceramic Fuels. High uranium density fuels were the focus of the ceramic fuels efforts. Accomplishments for FY15 primarily reflect the prioritization of identification and assessment of new ceramic fuels for light water reactors which have enhanced accident tolerance while also maintaining or improving normal operation performance, and exploration of advanced post irradiation examination techniques which will support more efficient testing and qualification of new fuel systems.

  9. Ceramic joining

    SciTech Connect

    Loehman, R.E.

    1996-04-01

    This paper describes the relation between reactions at ceramic-metal interfaces and the development of strong interfacial bonds in ceramic joining. Studies on a number of systems are described, including silicon nitrides, aluminium nitrides, mullite, and aluminium oxides. Joints can be weakened by stresses such as thermal expansion mismatch. Ceramic joining is used in a variety of applications such as solid oxide fuel cells.

  10. Advanced Turbine Technology Applications Project (ATTAP)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This report summarizes work performed in support of the development and demonstration of a structural ceramic technology for automotive gas turbine engines. The AGT101 regenerated gas turbine engine developed under the previous DOE/NASA Advanced Gas Turbine (AGT) program is being utilized for verification testing of the durability of next-generation ceramic components and their suitability for service at reference powertrain design conditions. Topics covered in this report include ceramic processing definition and refinement, design improvements to the test bed engine and test rigs, and design methodologies related to ceramic impact and fracture mechanisms. Appendices include reports by ATTAP subcontractors addressing the development of silicon nitride and silicon carbide families of materials and processes.

  11. 3-D inelastic analysis methods for hot section components. Volume 2: Advanced special functions models

    NASA Technical Reports Server (NTRS)

    Wilson, R. B.; Banerjee, P. K.

    1987-01-01

    This Annual Status Report presents the results of work performed during the third year of the 3-D Inelastic Analysis Methods for Hot Sections Components program (NASA Contract NAS3-23697). The objective of the program is to produce a series of computer codes that permit more accurate and efficient three-dimensional analyses of selected hot section components, i.e., combustor liners, turbine blades, and turbine vanes. The computer codes embody a progression of mathematical models and are streamlined to take advantage of geometrical features, loading conditions, and forms of material response that distinguish each group of selected components.

  12. Ceramic filters

    SciTech Connect

    Holmes, B.L.; Janney, M.A.

    1995-12-31

    Filters were formed from ceramic fibers, organic fibers, and a ceramic bond phase using a papermaking technique. The distribution of particulate ceramic bond phase was determined using a model silicon carbide system. As the ceramic fiber increased in length and diameter the distance between particles decreased. The calculated number of particles per area showed good agreement with the observed value. After firing, the papers were characterized using a biaxial load test. The strength of papers was proportional to the amount of bond phase included in the paper. All samples exhibited strain-tolerant behavior.

  13. The Center for Technology for Advanced Scientific Component Software (TASCS) Lawrence Livermore National Laboratory - Site Status Update

    SciTech Connect

    Epperly, T W

    2008-12-03

    This report summarizes LLNL's progress for the period April through September of 2008 for the Center for Technology for Advanced Scientific Component Software (TASCS) SciDAC. The TASCS project is organized into four major thrust areas: CCA Environment (72%), Component Technology Initiatives (16%), CCA Toolkit (8%), and User and Application Outreach & Support (4%). The percentage of LLNL's effort allocation is shown in parenthesis for each thrust area. Major thrust areas are further broken down into activity areas, LLNL's effort directed to each activity is shown in Figure 1. Enhancements, Core Tools, and Usability are all part of CCA Environment, and Software Quality is part of Component Technology Initiatives. The balance of this report will cover our accomplishments in each of these activity areas.

  14. A Validity Study of the Multiple-Choice Component of the Advanced Placement Chemistry Examination.

    ERIC Educational Resources Information Center

    Modu, Christopher C.; Taft, Hessy L.

    1982-01-01

    Compares performance of first-year general chemistry college students from 32 institutions with performance of Advanced Placement (AP) Chemistry Candidates in 1978 to provide a concurrent validity measure of the multiple-choice section of the AP chemistry examination. Average AP candidates scored significantly higher than average college students.…

  15. Ceramic applications in turbine engines

    NASA Technical Reports Server (NTRS)

    Byrd, J. A.; Janovicz, M. A.; Thrasher, S. R.

    1981-01-01

    Development testing activities on the 1900 F-configuration ceramic parts were completed, 2070 F-configuration ceramic component rig and engine testing was initiated, and the conceptual design for the 2265 F-configuration engine was identified. Fabrication of the 2070 F-configuration ceramic parts continued, along with burner rig development testing of the 2070 F-configuration metal combustor in preparation for 1132 C (2070 F) qualification test conditions. Shakedown testing of the hot engine simulator (HES) rig was also completed in preparation for testing of a spin rig-qualified ceramic-bladed rotor assembly at 1132 C (2070 F) test conditions. Concurrently, ceramics from new sources and alternate materials continued to be evaluated, and fabrication of 2070 F-configuration ceramic component from these new sources continued. Cold spin testing of the critical 2070 F-configuration blade continued in the spin test rig to qualify a set of ceramic blades at 117% engine speed for the gasifier turbine rotor. Rig testing of the ceramic-bladed gasifier turbine rotor assembly at 108% engine speed was also performed, which resulted in the failure of one blade. The new three-piece hot seal with the nickel oxide/calcium fluoride wearface composition was qualified in the regenerator rig and introduced to engine operation wiwth marginal success.

  16. Advances in compact manufacturing for shape and performance controllability of large-scale components-a review

    NASA Astrophysics Data System (ADS)

    Qin, Fangcheng; Li, Yongtang; Qi, Huiping; Ju, Li

    2017-01-01

    Research on compact manufacturing technology for shape and performance controllability of metallic components can realize the simplification and high-reliability of manufacturing process on the premise of satisfying the requirement of macro/micro-structure. It is not only the key paths in improving performance, saving material and energy, and green manufacturing of components used in major equipments, but also the challenging subjects in frontiers of advanced plastic forming. To provide a novel horizon for the manufacturing in the critical components is significant. Focused on the high-performance large-scale components such as bearing rings, flanges, railway wheels, thick-walled pipes, etc, the conventional processes and their developing situations are summarized. The existing problems including multi-pass heating, wasting material and energy, high cost and high-emission are discussed, and the present study unable to meet the manufacturing in high-quality components is also pointed out. Thus, the new techniques related to casting-rolling compound precise forming of rings, compact manufacturing for duplex-metal composite rings, compact manufacturing for railway wheels, and casting-extruding continuous forming of thick-walled pipes are introduced in detail, respectively. The corresponding research contents, such as casting ring blank, hot ring rolling, near solid-state pressure forming, hot extruding, are elaborated. Some findings in through-thickness microstructure evolution and mechanical properties are also presented. The components produced by the new techniques are mainly characterized by fine and homogeneous grains. Moreover, the possible directions for further development of those techniques are suggested. Finally, the key scientific problems are first proposed. All of these results and conclusions have reference value and guiding significance for the integrated control of shape and performance in advanced compact manufacturing.

  17. Ceramic high pressure gas path seal

    NASA Technical Reports Server (NTRS)

    Liotta, G. C.

    1987-01-01

    Stage 1 ceramic shrouds (high pressure turbine gas path seal) were developed for the GE T700 turbine helicopter engine under the Army/NASA Contract NAS3-23174. This contract successfully proved the viability and benefits of a Stage 1 ceramic shroud for production application. Stage 1 ceramic shrouds were proven by extensive component and engine testing. This Stage 1 ceramic shroud, plasma sprayed ceramic (ZrOs-BY2O3) and bond coating (NiCrAlY) onto a cast metal backing, offers significant engine performance improvement. Due to the ceramic coating, the amount of cooling air required is reduced 20% resulting in a 0.5% increase in horsepower and a 0.3% decrease in specific fuel consumption. This is accomplished with a component which is lower in cost than the current production shroud. Stage 1 ceramic shrouds will be introduced into field service in late 1987.

  18. Constitutive Theory Developed for Monolithic Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Janosik, Lesley A.

    1998-01-01

    With the increasing use of advanced ceramic materials in high-temperature structural applications such as advanced heat engine components, the need arises to accurately predict thermomechanical behavior that is inherently time-dependent and that is hereditary in the sense that the current behavior depends not only on current conditions but also on the material's thermomechanical history. Most current analytical life prediction methods for both subcritical crack growth and creep models use elastic stress fields to predict the time-dependent reliability response of components subjected to elevated service temperatures. Inelastic response at high temperatures has been well documented in the materials science literature for these material systems, but this issue has been ignored by the engineering design community. From a design engineer's perspective, it is imperative to emphasize that accurate predictions of time-dependent reliability demand accurate stress field information. Ceramic materials exhibit different time-dependent behavior in tension and compression. Thus, inelastic deformation models for ceramics must be constructed in a fashion that admits both sensitivity to hydrostatic stress and differing behavior in tension and compression. A number of constitutive theories for materials that exhibit sensitivity to the hydrostatic component of stress have been proposed that characterize deformation using time-independent classical plasticity as a foundation. However, none of these theories allow different behavior in tension and compression. In addition, these theories are somewhat lacking in that they are unable to capture the creep, relaxation, and rate-sensitive phenomena exhibited by ceramic materials at high temperatures. The objective of this effort at the NASA Lewis Research Center has been to formulate a macroscopic continuum theory that captures these time-dependent phenomena. Specifically, the effort has focused on inelastic deformation behavior associated

  19. Prepreg and Melt Infiltration Technology Developed for Affordable, Robust Manufacturing of Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Petko, Jeannie F.

    2004-01-01

    Affordable fiber-reinforced ceramic matrix composites with multifunctional properties are critically needed for high-temperature aerospace and space transportation applications. These materials have various applications in advanced high-efficiency and high-performance engines, airframe and propulsion components for next-generation launch vehicles, and components for land-based systems. A number of these applications require materials with specific functional characteristics: for example, thick component, hybrid layups for environmental durability and stress management, and self-healing and smart composite matrices. At present, with limited success and very high cost, traditional composite fabrication technologies have been utilized to manufacture some large, complex-shape components of these materials. However, many challenges still remain in developing affordable, robust, and flexible manufacturing technologies for large, complex-shape components with multifunctional properties. The prepreg and melt infiltration (PREMI) technology provides an affordable and robust manufacturing route for low-cost, large-scale production of multifunctional ceramic composite components.

  20. Microwave sintering of ceramics

    SciTech Connect

    Snyder, W.B.

    1989-01-01

    Successful adaptation of microwave heating to the densification of ceramic materials require a marriage of microwave and materials technologies. Using an interdisciplinary team of microwave and materials engineers, we have successfully demonstrated the ability to density ceramic materials over a wide range of temperatures. Microstructural evolution during microwave sintering has been found to be significantly different from that observed in conventional sintering. Our results and those of others indicate that microwave sintering has the potential to fabricate components to near net shape with mechanical properties equivalent to hot pressed or hot isostatically pressed material. 6 refs., 11 figs.

  1. Development of a propulsion system and component test facility for advanced radioisotope powered Mars Hopper platforms

    SciTech Connect

    Robert C. O'Brien; Nathan D. Jerred; Steven D. Howe

    2011-02-01

    Verification and validation of design and modeling activities for radioisotope powered Mars Hopper platforms undertaken at the Center for Space Nuclear Research is essential for proof of concept. Previous research at the center has driven the selection of advanced material combinations; some of which require specialized handling capabilities. The development of a closed and contained test facility to forward this research is discussed within this paper.

  2. Advancing Pharmacogenomics as a Component of Precision Medicine: How, Where, and Who?

    PubMed

    Johnson, J A; Weitzel, K W

    2016-02-01

    Pharmacogenomics is an important element of precision medicine. Advances in pharmacogenomics implementation have been made but significant barriers remain, including evidence, reimbursement, and clinician knowledge, among others. Widespread adoption of pharmacogenomics requires overcoming these barriers, a clinician champion group, which we propose will be pharmacists, and an easily accessible setting, which may be the community pharmacy. Whatever the path, it must be evidence-driven and pharmacogenomics must improve drug-related outcomes to become a standard of care.

  3. Advanced thermoplastic composites: An attractive new material for usage in highly loaded vehicle components

    SciTech Connect

    Mehn, R.; Seidl, F.; Peis, R.; Heinzmann, D.; Frei, P.

    1995-10-01

    Beside the lightweight potential and further well known advantages of advanced composite materials, continuous fiber reinforced thermoplastics employed in vehicle structural parts especially offer short manufacturing cycle times and an additional economically viable manufacturing process. Presenting a frame structure concept for two highly loaded vehicle parts, a safety seat and a side door, numerous features concerning the choice of suitable composite materials, design aspects, investigations to develop a thermoforming technique, mature for a series production of vehicle parts, are discussed.

  4. Advanced Technology Components for Model GTP305-2 Aircraft Auxiliary Power System.

    DTIC Science & Technology

    1980-02-01

    ified cold air component test rig, as shown in Figure 106. The radial turbine rotor was overhung on a double spring-loaded, hydrodynamically mounted...radial-axial turbine stage is characterized by an integrally ,- cast turbine rotor and a cast exhaust duct assembly. The Inte- grated Components Assembly... Rotor 83 3.4.9 Axial Turbine Aero/Mech Optimization 106 3.4.10 Axial Turbine Stator ill 3.4.11 Axial Turbine Rotor 124 3.4.14 Turbine Exhaust Diffuser

  5. Materials for Advanced Ultra-supercritical (A-USC) Steam Turbines – A-USC Component Demonstration

    SciTech Connect

    Purgert, Robert; Phillips, Jeffrey; Hendrix, Howard; Shingledecker, John; Tanzosh, James

    2016-10-01

    The work by the United States Department of Energy (U.S. DOE)/Ohio Coal Development Office (OCDO) advanced ultra-supercritical (A-USC) Steam Boiler and Turbine Materials Consortia from 2001 through September 2015 was primarily focused on lab scale and pilot scale materials testing. This testing included air- or steam-cooled “loops” that were inserted into existing utility boilers to gain exposure of these materials to realistic conditions of high temperature and corrosion due to the constituents in the coal. Successful research and development resulted in metallic alloy materials and fabrication processes suited for power generation applications with metal temperatures up to approximately 1472°F (800°C). These materials or alloys have shown, in extensive laboratory tests and shop fabrication studies, to have excellent applicability for high-efficiency low CO2 transformational power generation technologies previously mentioned. However, as valuable as these material loops have been for obtaining information, their scale is significantly below that required to minimize the risk associated with a power company building a multi-billion dollar A-USC power plant. To decrease the identified risk barriers to full-scale implementation of these advanced materials, the U.S. DOE/OCDO A-USC Steam Boiler and Turbine Materials Consortia identified the key areas of the technology that need to be tested at a larger scale. Based upon the recommendations and outcome of a Consortia-sponsored workshop with the U.S.’s leading utilities, a Component Test (ComTest) Program for A-USC was proposed. The A-USC ComTest program would define materials performance requirements, plan for overall advanced system integration, design critical component tests, fabricate components for testing from advanced materials, and carry out the tests. The AUSC Component Test was premised on the program occurring at multiple facilities, with the operating temperatures, pressure and/or size of

  6. High pressure ceramic heat exchanger

    DOEpatents

    Harkins, Bruce D.; Ward, Michael E.

    1998-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  7. High pressure ceramic heat exchanger

    DOEpatents

    Harkins, Bruce D.; Ward, Michael E.

    1999-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the reinforcing member and having a strengthening member wrapped around the refractory material. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  8. High pressure ceramic heat exchanger

    DOEpatents

    Harkins, B.D.; Ward, M.E.

    1998-09-22

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 5 figs.

  9. 24 CFR 242.47 - Insured advances for building components stored off-site.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... the name of the mortgagor while in transit and storage; and (2) Delivering or contracting for the... mortgagee shall warrant to HUD that the security instruments are a first lien on the building components covered by the instruments except for such other liens or encumbrances as may be approved by HUD....

  10. 24 CFR 242.47 - Insured advances for building components stored off-site.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the name of the mortgagor while in transit and storage; and (2) Delivering or contracting for the... mortgagee shall warrant to HUD that the security instruments are a first lien on the building components covered by the instruments except for such other liens or encumbrances as may be approved by HUD....

  11. 24 CFR 242.47 - Insured advances for building components stored off-site.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the name of the mortgagor while in transit and storage; and (2) Delivering or contracting for the... mortgagee shall warrant to HUD that the security instruments are a first lien on the building components covered by the instruments except for such other liens or encumbrances as may be approved by HUD....

  12. High-temperature ceramic receivers

    SciTech Connect

    Jarvinen, P. O.

    1980-01-01

    An advanced ceramic dome cavity receiver is discussed which heats pressurized gas to temperatures above 1800/sup 0/F (1000/sup 0/C) for use in solar Brayton power systems of the dispersed receiver/dish or central receiver type. Optical, heat transfer, structural, and ceramic material design aspects of the receiver are reported and the development and experimental demonstration of a high-temperature seal between the pressurized gas and the high-temperature silicon carbide dome material is described.

  13. Ceramic regenerator program

    NASA Technical Reports Server (NTRS)

    Franklin, Jerrold E.

    1991-01-01

    The feasibility of fabricating an Air Turbo Ramjet (ATR) regenerator containing intricate hydraulic passages from a ceramic material in order to allow operation with high temperature combustion gas and to reduce weight as compared with metallic materials was demonstrated. Platelet technology, ceramic tape casting, and multilayer ceramic packaging techniques were used in this fabrication of subscale silicon nitride components. Proof-of-concept demonstrations were performed to simulate a methane cooled regenerator for an ATR engine. The regenerator vane was designed to operate at realistic service conditions, i.e., 600 psi in a 3500 R (3040 F), 500 fps combustion gas environment. A total of six regenerators were fabricated and tested. The regenerators were shown to be able to withstand internal pressurization to 1575 psi. They were subjected to testing in 500 fps, 3560 R (3100 F) air/propane combustion products and were operated satisfactorily for an excess of 100 hr and 40 thermal cycles which exceeded 2460 R (2000 F).

  14. Flight service evaluation of an advanced composite empennage component on commercial transport aircraft. Phase 1: Engineering development

    NASA Technical Reports Server (NTRS)

    Ary, A.; Axtell, C.; Fogg, L.; Jackson, A.; James, A. M.; Mosesian, B.; Vanderwier, J.; Vanhamersveld, J.

    1976-01-01

    The empennage component selected for this program is the vertical fin box of the L-1011 aircraft. The box structure extends from the fuselage production joint to the tip rib and includes the front and rear spars. Various design options were evaluated to arrive at a configuration which would offer the highest potential for satisfying program objectives. The preferred configuration selected consists of a hat-stiffened cover with molded integrally stiffened spars, aluminum trussed composite ribs, and composite miniwich web ribs with integrally molded caps. Material screening tests were performed to select an advanced composite material system for the Advanced Composite Vertical Fin (ACFV) that would meet the program requirements from the standpoint of quality, reproducibility, and cost. Preliminary weight and cost analysis were made, targets established, and tracking plans developed. These include FAA certification, ancillary test program, quality control, and structural integrity control plans.

  15. Recent advances in fiber optics components for high speed data transmission

    NASA Astrophysics Data System (ADS)

    Leskovar, B.

    1991-04-01

    The concept of guided lightwave communication along optical fibers has stimulated a major new technology over the past two decades. This technology profoundly impacts communication and instrumentation systems as well as computer interconnections and systems architecture. In this paper, the state of the art of optical transmitters, low loss fiber waveguides, receivers, and associated electronics components are reviewed and summarized for optical data transmission systems operating between 100 Mbit/s and 2.5 Gbit/s. Emphasis is placed on high speed data transmission subassemblies, such as time division multiplexers and demultiplexers, clock and data recovery circuits, as well as optical transmitters and receivers. In addition, the performance of candidate components of the wide band digital transmission systems intended for deployment in large detection systems for particle physics is discussed.

  16. Heavy Lift Helicopter - Advanced Technology Component Program - Hub and Upper Controls

    DTIC Science & Technology

    1977-09-01

    and cost risk associated with the Engineering Development of an HLH system through the design, fabrication, demonstration and test of selected critical...HLH compcnents. Engineering Development or full-flight qualification of any component or concept was not the purpose of this program. The critical...titanium hub materials tcsts are repozted in Reference 2. Engineering material properties were developed for a 9 x lb x 36-inch 6Al-4V titanium alloy

  17. Advanced Foam Target Component Fabrication as Applied the Sandia Z Pinch Experiments

    NASA Astrophysics Data System (ADS)

    Schroen-Carey, Diana; Bailey, James; Bennett, Guy; Collins, Patrick; Dropinski, Stephen; Hebron, David; Hsieh, Edward; Motta, Brian; Sanford, Thomas; Youngblood, Kelly

    2000-10-01

    The Sandia pulsed power machine, Z, has developed into a unique test bed with unique targets, many of which incorporate foam components. These foam components must be very low density (5 - 14 mg/cm3), uniform and must meet tight dimensional tolerance. The experiments can also require an embedded diagnostic or capsule. To produce TPX (poly 4-methyl-1-pentene) foam of the required density and uniformity required a new process. We have developed a single solvent system that when cooled produces a uniform gel. This gel can be molded and can support embedded objects. The gel is then freeze dried to produce a dry, uniform foam. We will present an overview of this process and examples of some of the foam components produced. The most recent target was a 5 mg/cm3 foam, 10 mm in diameter, 15 mm tall with a 2 mm capsule (D2 filled) embedded in the center, and a 1000A gold coat on the outer diameter of the foam. Organizations: Schafer Corporation, Livermore, CA 94550. This work was done under the auspices of the Department of Energy contract DE-AC03-95SF20732. Sandia National Laboratories, Albuquerque, NM 87185. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

  18. Component evaluation for intersystem loss-of-coolant accidents in advanced light water reactors

    SciTech Connect

    Ware, A.G.

    1994-07-01

    Using the methodology outlined in NUREG/CR-5603 this report evaluates (on a probabilistic basis) design rules for components in ALWRs that could be subjected to intersystem loss-of-coolant accidents (ISLOCAs). The methodology is intended for piping elements, flange connections, on-line pumps and valves, and heat exchangers. The NRC has directed that the design rules be evaluated for BWR pressures of 7.04 MPa (1025 psig), PWR pressures of 15.4 MPa (2235 psig), and 177{degrees}C (350{degrees}F), and has established a goal of 90% probability that system rupture will not occur during an ISLOCA event. The results of the calculations in this report show that components designed for a pressure of 0.4 of the reactor coolant system operating pressure will satisfy the NRC survival goal in most cases. Specific recommendations for component strengths for BWR and PWR applications are made in the report. A peer review panel of nationally recognized experts was selected to review and critique the initial results of this program.

  19. New Advanced Fabrication Technique for Millimeter-Wave Planar Components based on Fluororesin Substrates using Graft Polymerization

    NASA Astrophysics Data System (ADS)

    Ito, Naoki; Mase, Atsushi; Kogi, Yuichiro; Seko, Noriaki; Tamada, Masao; Sakata, Eiji

    2008-06-01

    As the importance of advanced millimeter-wave diagnostics increases, a reliable and accurate fabrication technique for high-performance devices and relevant components is essential. We describe a new improved fabrication technique for millimeter-wave planar components, such as antennas using low-loss fluororesin substrates. A fragile adhesion between the copper foil and fluororesin substrate and the accuracy of the device pattern using conventional fabrication techniques have been prime suspects in the failure of the devices. In order to solve these problems, surface treatment of fluororesin films and a fabrication method using electro-fine-forming (EF2) are proposed. The peel adhesion strength between the metal and fluororesin films and the value of the dielectric constant of the fluororesin films before and after grafting are reported. A prototype antenna using conventional fluororesin substrates and grafted-poly(tetrafluoroethylene) (PTFE) films produced using the EF2 fabrication technique are also introduced.

  20. Ceramic fabrication R D

    SciTech Connect

    Not Available

    1990-01-01

    This project is separated into three tasks. The first task is a design and modeling effort to be carried out by MSE, Inc. The purpose of this task is to develop and analyze designs for various cohesive ceramic fabrication (CCF) components, including an MHD electrode for strategic defense initiative (SDI) applications and a high stress, low cost, reinforced ceramic component for armor applications. The MHD electrode design is substantially completed. A layered structure composed of molybdenum disilicide graded with quartz glass has been designed and analyzed using finite element methods. The design demonstrates the fabrication capabilities of the CCF process. The high stress, armor application component will be silicon carbide reinforced alumina in thick plates. 2 refs., 4 figs., 1 tab.