WorldWideScience

Sample records for ceramic composite material

  1. Ceramic composites: Enabling aerospace materials

    Science.gov (United States)

    Levine, S. R.

    1992-01-01

    Ceramics and ceramic matrix composites (CMC) have the potential for significant impact on the performance of aerospace propulsion and power systems. In this paper, the potential benefits are discussed in broad qualitative terms and are illustrated by some specific application case studies. The key issues in need of resolution for the potential of ceramics to be realized are discussed.

  2. FIBROUS CERAMIC-CERAMIC COMPOSITE MATERIALS PROCESSING AND PROPERTIES

    OpenAIRE

    1986-01-01

    The introduction of continuous fibers in a ceramic matrix can improve its toughness, if the fiber-matrix bonding is weak enough, due to matrix microcracking and fiber pull-out. Ceramic-ceramic composite materials are processed according to liquid or gas phase techniques. The most important are made of glass, carbide, nitride or oxide matrices reinforced with carbon, SiC or Al2O3 fibers.

  3. Tribology of ceramics and composites materials science perspective

    CERN Document Server

    Basu, Bikramjit

    2011-01-01

    This book helps students and practicing scientists alike understand that a comprehensive knowledge about the friction and wear properties of advanced materials is essential to further design and development of new materials. With important introductory chapters on the fundamentals, processing, and applications of tribology, the book then examines in detail the nature and properties of materials, the friction and wear of structural ceramics, bioceramics, biocomposites, and nanoceramics, as well as lightweight composites and the friction and wear of ceramics in a cryogenic environment.

  4. Modeling the Mechanical Behavior of Ceramic Matrix Composite Materials

    Science.gov (United States)

    Jordan, William

    1998-01-01

    Ceramic matrix composites are ceramic materials, such as SiC, that have been reinforced by high strength fibers, such as carbon. Designers are interested in using ceramic matrix composites because they have the capability of withstanding significant loads while at relatively high temperatures (in excess of 1,000 C). Ceramic matrix composites retain the ceramic materials ability to withstand high temperatures, but also possess a much greater ductility and toughness. Their high strength and medium toughness is what makes them of so much interest to the aerospace community. This work concentrated on two different tasks. The first task was to do an extensive literature search into the mechanical behavior of ceramic matrix composite materials. This report contains the results of this task. The second task was to use this understanding to help interpret the ceramic matrix composite mechanical test results that had already been obtained by NASA. Since the specific details of these test results are subject to the International Traffic in Arms Regulations (ITAR), they are reported in a separate document (Jordan, 1997).

  5. Preparation and Microstructure of Glass-ceramics and Ceramic Composite Materials

    Institute of Scientific and Technical Information of China (English)

    HE Feng; XIE Junlin; HAN Da

    2008-01-01

    The technology and microstructure of glass-ceramics and ceramic composite materials were studied.A suitable ceramic body was chosen on the basis of the sintering temperature of CaO-Al2O3-SiO2 system glass-ceramics.According to the expansion coefficient of the ceramic body,that of CaO-Al2O3-SiO2 system glass-ceramics was adjusted.a-wollastonite was found present as the major crystalline phase in glass-ceramic.The CaO-Al2O3-SiO2 system glass-ceramic layer and ceramic body could be sintered together by adjusting the sintering period.The compositions of glass-ceramic layer and ceramic body diffuse mutually at 1100℃.resulting in an interface between them.To achieve good sintered properties of glass-ceramics and the chosen ceramic body,at least a four-hour sintering time is used.

  6. Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 3 - Ceramics and ceramic-matrix composites

    Science.gov (United States)

    Levine, Stanley R. (Editor)

    1992-01-01

    The present volume discusses ceramics and ceramic-matrix composites in prospective aerospace systems, monolithic ceramics, transformation-toughened and whisker-reinforced ceramic composites, glass-ceramic matrix composites, reaction-bonded Si3N4 and SiC composites, and chemical vapor-infiltrated composites. Also discussed are the sol-gel-processing of ceramic composites, the fabrication and properties of fiber-reinforced ceramic composites with directed metal oxidation, the fracture behavior of ceramic-matrix composites (CMCs), the fatigue of fiber-reinforced CMCs, creep and rupture of CMCs, structural design methodologies for ceramic-based materials systems, the joining of ceramics and CMCs, and carbon-carbon composites.

  7. Actively Cooled Ceramic Composite Nozzle Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase I Project demonstrated the capability of the Pyrowave? manufacturing process to produce fiber-reinforced ceramics (FRCs) with integral metal features, such...

  8. Mechanical behaviour of engineering materials. Metals, ceramics, polymers, and composites

    Energy Technology Data Exchange (ETDEWEB)

    Roesler, Joachim; Baeker, Martin [TU Braunschweig (Germany). Inst. fuer Werkstoffe; Harders, Harald

    2007-07-01

    How do engineering materials deform when bearing mechanical loads? To answer this crucial question, the book bridges the gap between continuum mechanics and materials science. The different kinds of material deformation (elasticity, plasticity, fracture, creep, fatigue) are explained in detail. The book also discusses the physical processes occurring during the deformation of all classes of engineering materials (metals, ceramics, polymers, and composites) and shows how these materials can be strengthened to meet the design requirements. It provides the knowledge needed in selecting the appropriate engineering material for a certain design problem.

  9. Processing and Material Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics.

    Science.gov (United States)

    Cox, Sarah B.

    2014-01-01

    The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

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

    Science.gov (United States)

    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.

  11. Effect of Rare Earth Phosphate Composite Materials on Cleanout Oil-Dirty Property of Ceramics

    Institute of Scientific and Technical Information of China (English)

    Liang Jinsheng; Zhang Jin; Liang Guangchuan; Wang Lijuan; Li Guosheng; Meng Junping; Pan Yanfen

    2004-01-01

    The ceramics with cleaning easily up oil-dirty property were prepared by doping enamel slurry with rare earth elements phosphate composite materials, and then the influence mechanisms of rare earth elements phosphate composite materials on the cleaning easily up oil-dirty property of ceramic were studied by testing the surface tension and contact angle of water, latex stability inside of ceramic product. Results that the ceramic doped enamel slurry with rare earth phosphate composite materials can reduce obviously the surface tension and contact angle of water, and make latex more stable, and so the ceramics possess excellent cleanout oil-dirty property.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Continuous Fiber Ceramic Composites

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-09-01

    Fiber-reinforced ceramic composites demonstrate the high-temperature stability of ceramics--with an increased fracture toughness resulting from the fiber reinforcement of the composite. The material optimization performed under the continuous fiber ceramic composites (CFCC) included a series of systematic optimizations. The overall goals were to define the processing window, to increase the robustinous of the process, to increase process yield while reducing costs, and to define the complexity of parts that could be fabricated.

  14. Fabrication of functionally gradient materials with internal channels in ceramics and ceramic composites

    Science.gov (United States)

    Shin, Hyea-Weon

    Functionally Gradient Materials (FGMs) are inhomogeneous materials whose compositions vary from one phase to another. By tailoring the inhomogeneous properties, FGMs can be used to reduce the stresses that are caused by severe thermal gradients. Thermal gradient loading can further be compensated by heat transfer into a cooling fluid circulating in a network of channels and manifolds. In an envisioned application, heat from a localized source is transferred to the cooling fluid, easing sharp thermal loads while minimizing the unwanted spread of heat energy to the ambient surroundings. This study reports on the fabrication of functionally gradient ceramics and the embedding of simple internal channels within these ceramics. Functional gradiency (variation of composition) is built in via the layering of different components across the thickness of a plate sample. Traditional powder processing techniques are applied to fabricate the test pieces, and recently developed methods of joining are used to build assemblies from individually sintered plate layers. For a well-formed FGM to be made, materials parameters need to be selected based on mechanical, thermal and chemical properties. As a class, ceramics are hard, wear-resistant, refractory, electrically and thermally insulative, nonmagnetic, chemically stable, and oxidation-resistant. However, because of their brittleness, ceramics with minute channels are difficult to machine. Instead, for this study, a graphite fugitive phase is used as a spacer to support channel volumes within a ceramic powder compact; during pre-sintering, the graphite burns out to expose a network of channels. Full sintering fixes the final shape. At the operating temperatures of the ovens used in our fabrication study, sintering of alumina, partially stabilized zirconia, fully stabilized zirconia and hydroxyapatite have been successful, and these ceramic powders form the basis of the present fabrication studies. Inhomogeneities inherent in the

  15. Composition, Processing Technology and Property of Ceramic Die Materials Containing Rare Earth Additives

    Institute of Scientific and Technical Information of China (English)

    Xiao Guangchun; Xu Chonghai; Fang Bin

    2007-01-01

    Development and application of new ceramic die materials is one of the important topics in the field of die research. The composition, processing technology, mechanical property and engineering performance of the ceramic materials such as cermet, ZTA, TZP, TZP/Al2O3, TZP/TiC/Al2O3, PSZ and Sialon, etc., with rare earth yttrium, lanthanum and cerium, and so on working as additives, were investigated and analyzed in the present study. Problems existed in the research and application of rare earth ceramic die materials were discussed. Rare earth additives can effectively improve the mechanical property and engineering performance of ceramic die materials. Thus, it will have further perspectives of wider application. More attention should be paid in the future to the toughening and strengthening of the ceramic die materials, the adding forms and kinds of rare earth elements and acting mechanisms of rare earth additives in ceramic die materials.

  16. Annual Conference on Composites and Advanced Ceramic Materials, 11th, Cocoa Beach, FL, Jan. 18-23, 1987, Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1987-08-01

    The present conference on advanced ceramic materials discusses topics in the fields of NDE, coating/joining/tribology techniques, fracture and interface phenomena, whisker- and particulate-reinforced composites, fiber and whisker properties, SiC and Si/sub 3/N/sub 4/, glass/glass-ceramic matrix composites, alumina-matrix composites, ceramic materials for space structures, and SiC- and Si/sub 3/N/sub 4/-matrix composites. Attention is given to ceramic characterization by thermal wave imaging, an advanced ceramic-to-metal joining process, the fracture modes of brittle-matrix unidirectional composites, the oxidation of SiC-containing composites, particulate matter in SiC whiskers, corrosion reactions in SiC ceramics, melt-infiltrated ceramic-matrix composites, environmental effects in toughened ceramics, and a ceramic composite heat exchanger.

  17. Effect of Rare Earth Composite Ceramic Materials on Oil Combustion of Oil-Burning Boiler

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The rare earth composite ceramic materials were prepared using rare earths and far infrared natural mineral. The effects of the as-prepared ceramic materials on the oil consumption and air pollutants emissions of oil-burning boiler were investigated. The results show that the composite ceramic materials can radiate higher intensity of far infrared. The molecular movement is strengthened and the chemical bonds of the molecules are easily ruptured when the diesel oil is dealt with the composite materials. The oil-saving rate of the RBS·VH-1.5 boiler dealt with the rare earth composite ceramic materials is 3.49%, and the reducing rates of CO and NO in the exhaust gas are 25.4% and 9.7%, respectively.

  18. Development of Ceramic Fibers for Reinforcement in Composite Materials

    Science.gov (United States)

    Gates, L. E.; Lent, W. E.; Teague, W. T.

    1961-01-01

    the. testing apparatus for single fiber tensile strength increased the precision. of tests conducted on nine fibers. The highest mean tensile strength, a value of 295,000 pounds per square inch, was obtained with R-141 fibers. Treatment of R-74 fibers with anhydrous Linde A-1100 silane finish improved its mean fiber tensile strength by 25 percent. The lapse of time after fiber formation had no measurable effect on tensile strength. A static heating test conducted with various high melting fibers indicated that Fiberfrax and R-108 underwent no significant changes in bulk volume or resiliency on exposure to 2750 degrees Fahrenheit (1510 degrees Centigrade) in an oxidizing atmosphere. For fiber-resin composition fabrication, ten fiber materials were selected on the bases of high fiber yield, fusion temperature, and type of composition. Fiberfrax, a commercial ceramic fiber, was included for comparison. A new, more effective method of removing pellets from blown fibers was developed. The de-pelletized fibers were treated with a silane finish and felted into ten-inch diameter felts prior to resin impregnation. Composites containing 30 percent by weight of CTL 91-LD phenolic resin were molded under high pressure from the impregnated felts and post-cured to achieve optimum properties. Flexural strength, flexural modules of elasticity, and punch shear strength tests were conducted on the composite specimens. The highest average flexural strength obtained was 19,958 pounds per square inch with the R-74-fiber-resin composite. This compares very favorably with the military specification of 13,000 pounds per square inch flexural strength for randomly oriented fiber reinforced composites. The highest punch shear strength (11,509 pounds per square inch) was obtained with the R-89 fiber-resin composite. The effects of anhydrous fiber finishes on composite strength were not clearly indicated. Plasma arc tests at a heat flux of 550 British Thermal Units per square foot per second on

  19. Ceramic Laser Materials

    Directory of Open Access Journals (Sweden)

    Guillermo Villalobos

    2012-02-01

    Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

  20. Dynamic characterization of monolithic and composite ceramic materials using Hopkinson bar

    OpenAIRE

    2002-01-01

    5 pages, 11 figures. [EN] The mechanical behaviour of monolithic and composite ceramic materials was analysed under impact conditions, using the Hopkinson bar to study the response and failure modes. The materials considered were alumina (Al2O3) and silicon carbide platelet / alumina matrix (Al2O3/ SiCpl) composites. Because of the high hardness of ceramics, modifications of the conventional Hopkinson bar device were done to prevent the damage of the bars surface. Stress-strain curves obta...

  1. Multiwalled carbon nanotube-reinforced ceramic matrix composites as a promising structural material

    Energy Technology Data Exchange (ETDEWEB)

    Estili, Mehdi, E-mail: mehdiestili@gmail.co [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Department of Materials Processing, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Kwon, Hansang; Kawasaki, Akira; Cho, Seungchan; Takagi, Kenta; Kikuchi, Keiko [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Kawai, Masayoshi [Institute of Materials Structure Science, High Energy Accelerator Research Organization, Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2010-03-15

    In this paper, we introduce fully dense, multiwalled carbon nanotube (MWCNT)-reinforced ceramic matrix composites recently processed by a novel powder technology in our laboratory to be considered as a promising potential structural materials for employment in severe working conditions. A strategy is also offered to investigate the effect of working condition on the mechanical properties of MWCNTs embedded in the ceramic matrix for a reliable material selection for the working conditions needed.

  2. Characterization of composite materials based on cement-ceramic powder blended binder

    Science.gov (United States)

    Kulovaná, Tereza; Pavlík, Zbyšek

    2016-06-01

    Characterization of newly developed composite mortars with incorporated ceramic powder coming from precise brick cutting as partial Portland cement replacement up to 40 mass% is presented in the paper. Fine ceramic powder belongs to the pozzolanic materials. Utilization of pozzolanic materials is accompanied by lower request on energy needed for Portland clinker production which generally results in lower production costs of blended binder and lower CO2 emission. In this paper, the ceramic powder is used in cement based mortar composition in amount of 8, 16, 24, 32, and 40 mass% of cement. Chemical composition of ceramic powder is analyzed by X-Ray Fluorescence and X-Ray Diffraction. The particle size distribution of ceramics is accessed on laser diffraction principle. For 28 days cured mortar samples, basic physical and mechanical properties are experimentally determined. The obtained results demonstrate that ceramic powder has potential to replace a part of Portland cement in composition of cement based composites and to reduce negative environmental impact of their production.

  3. Ceramic materials for energy and environmental applications: Functionalizing of properties by tailored compositions

    DEFF Research Database (Denmark)

    Ivanova, Mariya; Ricote, Sandrine; Baumann, Stefan

    2013-01-01

    Stable social development requires novel approaches for energy production, distribution and storage combined with reasonable restrictions of the environmental impact. The fuel cell-based technologies, as well as the separation of gases from mixtures, particularly implemented into innovative power....... This chapter is dedicated to the fascinating world of tailoring ceramic materials for energy and environmental applications. Selected approaches to tune ceramics will be discussed to illustrate the versatile effects that compositional variation can have on the macroscopic properties, e.g. the conductivity...... additives and substituents on sinterability, electrical/electrochemical properties and stability of selected ceramic materials for energy and environmental applications. The material variety will cover ceramic materials with different crystal structures like fluorites, perovskites, pyrochlores, fergusonites...

  4. Structural ceramic coatings in composite microtruss cellular materials

    Energy Technology Data Exchange (ETDEWEB)

    Bele, E.; Bouwhuis, B.A.; Codd, C. [Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario (Canada); Hibbard, G.D., E-mail: glenn.hibbard@utoronto.ca [Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario (Canada)

    2011-09-15

    Graphical abstract: The compressive strength increase per unit sleeve thickness of Al cores reinforced with Al{sub 2}O{sub 3} sleeves is lower than the corresponding strength increase when the same cores are reinforced with nanocrystalline Ni (n-Ni) sleeves (left). However, because anodizing is a transformative surface treatment, the Al{sub 2}O{sub 3} coating was able to achieve this performance increase with little overall weight penalty (right). Display Omitted Highlights: {yields} A new type of metal/ceramic microtruss cellular composite has been created. {yields} Reinforcing sleeves of Al{sub 2}O{sub 3} were deposited on low density Al microtruss cores. {yields} Significant compressive strength increases were seen at virtually no weight penalty. {yields} Failure mechanisms were studied by electron microscopy and finite element analysis. {yields} Buckling, sleeve wrinkling, and coating fracture dictated the compressive strength. - Abstract: In the present study, anodizing was used to produce Al{sub 2}O{sub 3} coatings in a conventional 3003 aluminum alloy microtruss core; a 38.5 {mu}m thick anodic coating provided a 143% increase in compressive strength. Finite-element analyses were used to illustrate the dependence of the compressive strength and failure mechanism on the thickness of the anodic coating. At low thicknesses the microtruss strength is dictated by global bucking of the internal struts. However, at higher thicknesses the compressive strength is controlled by coating fracture and local deformation in the hinge region of the struts. Regardless of the failure mechanism, the compressive strength of the composite microtruss increased with increasing anodic coating thickness, with very little corresponding weight penalty.

  5. Research on toughening mechanisms of alumina matrix ceramic composite materials improved by rare earth additive

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xihua; LIU Changxia; LI Musen; ZHANG Jianhua

    2008-01-01

    Mixed rare earth elements were incorporated into alumina ceramic materials. Hot-pressing was used to fabricate alumina matrix composites in nitrogen atmosphere protection. Microstructures and mechanical properties of the composites were tested. It was indicated that the bending strength and fracture toughness of alumina matrix ceramic composites sintered at 1550℃ and 28 Mpa for 30 min were improved evidently. Besides mixed rare earth elements acting as a toughening phase, AlTiC master alloys were also added in as sintering assistants, which could prompt the formation of transient liquid phase, and thus nitrides of rare earth elements were produced. All of the above were beneficial for improving the mechanical properties of alumina matrix ceramic composites.

  6. Characterization of Mechanical Damage Mechanisms in Ceramic and Polymeric Matrix Composite Materials

    Science.gov (United States)

    1991-11-01

    Ceram. Soc., 71, pp. C371- C373 (1988). 10. A. Kvell and 0. V. Bakun, Acta Metall., 34, pp. 1315-1319 (1986). 11. W. Kollenberg, J. Mat. Sci., 23, pp...neous Materials and Composites," ASTM STP 808, ed. R. Chait and R. Papirno, American Society for Testing and Materials, Philadelphia, 175-186, 1983. 7...Design (Seventh Conference), ASTM STP 893, ed. J. M. Whitney, American Society for Testing and Materials, Philadelphia, 115-139, 1986. 12. J. Lankford

  7. Electric and Magnetic Properties of a New Ferrite-Ceramic Composite Material

    Institute of Scientific and Technical Information of China (English)

    张怀武; 石玉; 钟智勇

    2002-01-01

    We have investigated a new ferrite-ceramic composite material with inductive and capacitive properties fabricated by a solid-state reaction method. We analyse the effects of the composite mechanism and microstructure on the magnetic and electric properties. The results show that the new materials can be used not only as inductor materials, but also as capacitor materials in the wide frequency range of 1 kHz-1.8GHz. The real part of permeability of the composite material is between 10 and 5.6, the imaginary part of permeability is between 1.2 and 0.5, and the dielectric constant is about ten times larger than that of ordinary ferrite materials. It is suggested that the new composite materials will be widely used in anti-electromagnetic interference fields and radio frequency communication fields

  8. Characterization of Mechanical Damage Mechanisms in Ceramic Composite Materials.

    Science.gov (United States)

    1986-07-01

    Studies of Y203 - Containing Tetragonal ZrO2 Polycrystals (Y- TZP )", pp. 352-70 in Advances in Ceramics, Vol. 12, Science and Technology of Zirconia II...temperature dependent, and is interpreted in term-s of TE1l evidence of dislocation activity, and an hypothesized tetragonal -to- cubic transformation...tation and temperature dependent, and is interpreted in terms of TEM evi- dence of dislocation activity, and an hypothesized tetragonal -to- cubic

  9. Preparation and Photocatalytic Property of TiO2/Diatomite-Based Porous Ceramics Composite Materials

    Directory of Open Access Journals (Sweden)

    Shuilin Zheng

    2012-01-01

    Full Text Available The diatomite-based porous ceramics was made by low-temperature sintering. Then the nano-TiO2/diatomite-based porous ceramics composite materials were prepared by hydrolysis deposition method with titanium tetrachloride as the precursor of TiO2 and diatomite-based porous as the supporting body of the nano-TiO2. The structure and microscopic appearance of nano-TiO2/diatomite-based porous ceramics composite materials was characterized by XRD and SEM. The photocatalytic property of the composite was investigated by the degradation of malachite green. Results showed that, after calcination at 550°C, TiO2 thin film loaded on the diatomite-based porous ceramics is anatase TiO2 and average grain size of TiO2 is about 10 nm. The degradation ratio of the composite for 5 mg/L malachite green solution reached 86.2% after irradiation for 6 h under ultraviolet.

  10. A bulk metal/ceramic composite material with a cellular structure

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhankui; YAO Kefu; LI Jingfeng

    2006-01-01

    A bulk metal/ceramic composite material with a honeycomb-like micro-cell structure has been prepared by sintering the spherical Al90Mn9Ce1 alloy powders clad by Al2O3 nano-powder with the spark plasma sintering (SPS) technique. The as-prepared material consists of Al90Mn9Ce1 alloy cell and closed Al2O3 ceramic cell wall. The diameter of the cells is about 20―40 μm, while a thickness of the cell wall is about 1―2 μm. The ultimate compressive strength of the as-sintered materials is about 514 MPa, while its fracture strain is up to about 0.65 %. This composite material might possess good anti-corrosion, thermal endurance and other potential properties due to its unique microstructure. The result shows that the Al90Mn9Ce1/Al2O3 composite powders can be sintered by spark plasma sintering technique despite the large difference in their sintering temperature. This work offers a way of designing and preparing metal/ceramic composite material with functional property.

  11. Annual Conference on Composites and Advanced Ceramic Materials, 12th, Cocoa Beach, FL, Jan. 17-22, 1988, Proceedings. Parts 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    1988-10-01

    The present conference discusses topics in the development status of advanced ceramics, the engineering applications of ceramic-matrix composites, modeling and theoretical considerations of engineering ceramics, the role of interfaces in ceramic-matrix composites, and polycrystalline oxide-matrix composites. Also discussed are glass- and glass-ceramic-matrix composites, carbide- and nitride-matrix composites, the synthesis methods as well as the properties and applications of ceramic matrix-reinforcing whiskers, fibers, and powders, and various SDI-related advanced ceramic materials for use in orbital systems.

  12. Prediction of Thermophysical and Thermomechanical Characteristics of Porous Carbon-Ceramic Composite Materials of the Heat Shield of Aerospace Craft

    Science.gov (United States)

    Reznik, S. V.; Prosuntsov, P. V.; Mikhailovskii, K. V.

    2015-05-01

    A procedure for predicting thermophysical and thermomechanical characteristics of porous carbon-ceramic composite materials of the heat shield of aerospace craft as functions of the type of reinforcement, porosity of the structure, and the characteristics of the material's components has been developed. Results of mathematical modeling of the temperature and stressed-strained states of representative volume elements for determining the characteristics of a carbon-ceramic composite material with account taken of its anisotropy have been given.

  13. Influence of Composite Phosphate Inorganic Antibacterial Materials Containing Rare Earth on Activated Water Property of Ceramics

    Institute of Scientific and Technical Information of China (English)

    梁金生; 梁广川; 祁洪飞; 吴子钊; 冀志江; 金宗哲

    2004-01-01

    Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating water and improving seed germinative property were tested by nuclear magnetic resonance (NMR) and the method of testing oxygen dissolved in activated water. Results show that the half peak width of 17O-NMR for tap water activated by the antibacterial ceramic drops from 115.36 to 99.15 Hz, and oxygen concentrations of activated water increase by 20%, germinate rate of horsebean and earthnut seeds increases by 12.5% and 7.5%, respectively. Therefore antibacterial ceramic doped enamel slurry with inorganic antibacterial additives containing rare earth can reduce the volume of clusters of water molecules, improve activation of tap water, and promote plant seeds germinate.

  14. On the surface elemental composition of non-corroded and corroded dental ceramic materials in vitro.

    Science.gov (United States)

    Milleding, P; Karlsson, S; Nyborg, L

    2003-06-01

    Dental ceramics are traditionally looked upon as inert materials. As many are glass phased, it may be hypothesized that they will be subjected to glass corrosion in aqueous environments. The aim of the study was therefore to analyze the surface elemental composition of glass-phased and all-crystalline ceramics, before and after low- and high-intensity, in vitro corrosion (milli-Q-water at 37+/-2 degrees C for 18 h and 4% acetic acid at 80+/-2 degrees C for 18 h, respectively). The analysis of the surface elemental composition was performed using ESCA. The hypothesis was confirmed. After high-intensity corrosion, the complete wash out of alkali ions, alkaline-earth ions and elemental alumina was found, leaving behind a surface totally dominated by silica. The all-crystalline ceramics, densely sintered alumina and yttria-partially stabilized tetragonal zirconia, displayed only minor surface changes, even after high-intensity corrosion. In comparison to the corrosion testing in acid, the corrosion process in milli-Q-water did not produce different results in principle, except for the lower magnitude of the depletion of alkali ions and the virtually unchanged level of elemental alumina. Unexpectedly, no substantial difference in surface degradation was found between the glass ceramic and the ordinary porcelain-fused-to-metal ceramic or between ceramics of higher sintering temperature and those of low or ultra-low sintering temperature. The composition and microstructure alone did not appear to provide a full explanation for the inter-individual differences in surface corrosion when exposed to comparable environmental conditions.

  15. Ceramic Matrix Composites .

    Directory of Open Access Journals (Sweden)

    J. Mukerji

    1993-10-01

    Full Text Available The present state of the knowledge of ceramic-matrix composites have been reviewed. The fracture toughness of present structural ceramics are not enough to permit design of high performance machines with ceramic parts. They also fail by catastrophic brittle fracture. It is generally believed that further improvement of fracture toughness is only possible by making composites of ceramics with ceramic fibre, particulate or platelets. Only ceramic-matrix composites capable of working above 1000 degree centigrade has been dealt with keeping reinforced plastics and metal-reinforced ceramics outside the purview. The author has discussed the basic mechanisms of toughening and fabrication of composites and the difficulties involved. Properties of available fibres and whiskers have been given. The best results obtained so far have been indicated. The limitations of improvement in properties of ceramic-matrix composites have been discussed.

  16. The diametral tensile strength and hydrostability of polymer-ceramic nano-composite (pcnc) material prototypes

    Science.gov (United States)

    Yepez, Johanna

    Statement of the problem: There is a weak connection between the filler and the resin matrix of dental composites caused primarily by hydrolysis of silane coupling agent, therefore, jeopardizing the mechanical properties of the dental restorations. Purpose: The purpose of this study was to compare the diametral tensile strength (DTS) of a nano-mechanically bonded polymer ceramic nano composite (pcnc) versus the chemically bonding prototype polymer ceramic nano composite (pcnc) fabricated by using hydrolytically stable interphase. Materials and Methods: Composites were made with 60wt % filler, 38% triethyleneglycol dimethacrylate (TEDGMA), 1% camphorquinone (CQ) and 1% 2-(dimethylamino) ethyl methacrylate (DMAEMA). Tests for DTS were performed using a universal testing machine. The disk-shaped specimens were loaded in compression between two supporting plates at a crosshead speed of 0.5 mm/min until fracture. The samples, measuring 3 mm in height and 6 mm in diameter, were produced in a round stainless steel (SS) mold. A total of 144 samples were created. Groups of 48 samples were made for each of three different fillers. Specimens were soaked in artificial saliva at 37° for four time periods, dry(t=0), 1 day, 7 days, 28 days). At the end of each soaking time DTS tests were performed. Results: There where statistically significant differences in the DTS between the filler groups and the soaking times (p=composition and bonding interphase of resin base composites promise improvements of mechanical properties, decreasing the incidence of clinical failure of posterior composite restorations, hence resulting in a more ideal restorative material for use in posterior segment. The results of this investigation showed that the deficiency of hydrostability in dental composites is a detrimental factor in the mechanical behavior. The silanation of the filler particles have a positive influence on the mechanical properties of dental composites but the hydrolysis of the silane

  17. Synthesis of steel slag ceramics:chemical composition and crystalline phases of raw materials

    Institute of Scientific and Technical Information of China (English)

    Li-hua Zhao; Wei Wei; Hao Bai; Xu Zhang; Da-qiang Cang

    2015-01-01

    Two types of porcelain tiles with steel slag as the main raw material (steel slag ceramics) were synthesized based on the CaO–Al2O3–SiO2 and CaO–MgO–SiO2 systems, and their bending strengths up to 53.47 MPa and 99.84 MPa, respectively, were obtained. The presence of anorthite,α-quartz, magnetite, and pyroxene crystals (augite and diopside) in the steel slag ceramics were very different from the composition of traditional ceramics. X-ray diffraction (XRD) and electron probe X-ray microanalysis (EPMA) results illustrated that the addition of steel slag reduced the temperature of extensive liquid generation and further decreased the firing temperature. The considerable contents of glass-modifying oxide liquids with rather low viscosities at high temperature in the steel slag ceramic adobes promoted element diffusion and crystallization. The results of this study demonstrated a new approach for extensive and effective recycling of steel slag.

  18. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    Science.gov (United States)

    Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

    2016-01-12

    A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

  19. Micromechanical Evaluation of Ceramic Matrix Composites

    Science.gov (United States)

    1991-02-01

    Materials Sciences Corporation AD-A236 756 M.hM. 9 1 0513 IEIN HIfINU IIl- DTIC JUN 06 1991 MICROMECHANICAL EVALUATION OF S 0 CERAMIC MATRIX COMPOSITES C...Classification) \\() Micromechanical Evaluation of Ceramic Matrix Composites ) 12. PERSONAL AUTHOR(S) C-F. Yen, Z. Hashin, C. Laird, B.W. Rosen, Z. Wang 13a. TYPE...and strengthen the ceramic composites. In this task, various possibilities of crack propagation in unidirectional ceramic matrix composites under

  20. Data on post irradiation experiments of heat resistant ceramic composite materials. PIE for 97M-13A

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Shin-ichi; Ishihara, Masahiro; Souzawa, Shizuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Sekino, Hajime [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The research on the radiation damage mechanism of heat resistant ceramic composite materials is one of the research subjects of the innovative basic research in the field of high temperature engineering, using the High Temperature engineering Test Reactor (HTTR). Three series of irradiation tests on the heat resistant ceramic composite materials, first to third irradiation test program, were carried out using the Japan Material Testing Reactor (JMTR). This is a summary report on the first irradiation test program; irradiation induced dimensional change, thermal expansion coefficient, X-ray diffraction and {gamma}-ray spectrum are reported. (author)

  1. Calcium phosphate/microgel composites for 3D powderbed printing of ceramic materials.

    Science.gov (United States)

    Birkholz, Mandy-Nicole; Agrawal, Garima; Bergmann, Christian; Schröder, Ricarda; Lechner, Sebastian J; Pich, Andrij; Fischer, Horst

    2016-06-01

    Composites of microgels and calcium phosphates are promising as drug delivery systems and basic components for bone substitute implants. In this study, we synthesized novel composite materials consisting of pure β-tricalcium phosphate and stimuli-responsive poly(N-vinylcaprolactam-co-acetoacetoxyethyl methacrylate-co-vinylimidazole) microgels. The chemical composition, thermal properties and morphology for obtained composites were extensively characterized by Fourier transform infrared, X-ray photoelectron spectroscopy, IGAsorp moisture sorption analyzer, thermogravimetric analysis, granulometric analysis, ESEM, energy dispersive X-ray spectroscopy and TEM. Mechanical properties of the composites were evaluated by ball-on-three-balls test to determine the biaxial strength. Furthermore, initial 3D powderbed-based printing tests were conducted with spray-dried composites and diluted 2-propanol as a binder to evaluate a new binding concept for β-tricalcium phosphate-based granulates. The printed ceramic bodies were characterized before and after a sintering step by ESEM. The hypothesis that the microgels act as polymer adhesive agents by efficient chemical interactions with the β-tricalcium phosphate particles was confirmed. The obtained composites can be used for the development of new scaffolds.

  2. Mechanical Properties of a new Dental all-ceramic Material-zirconia Toughened Nanometer-ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    CHAI Feng; XU Ling; CHAO Yong-lie; LIAO Yun-mao; ZHAO Yi-min

    2003-01-01

    Objectives:All-ceramic dental restorations are attractive to the dental community because of their advantages.But they're also challenged by relatively low flexural strength and intrinsic poor resistance to fracture.This paper aims to investigate mechanical properties of a new dental all-ceramic material, i.e. zirconia toughened nanometer-ceramic composite (α-Al2O3/nZrO2).Methods:α-Al2O3/nZrO2 ceramics powder (W) was processed with combined methods of chemical co-precipitation method and ball milling. Scanning electron microscopy (SEM)was used to determine the particle size distribution and to characterize the particle morphology of the powders. Four kinds of powders with different ZrO2 content (5wt%, 10wt%, 15wt% and 20wt%) were prepared by using α-Al2O3 powder to dilute the higher ZrO2 content powder (W). The ceramic matrix compacts were made by slip-casting technique and sintering to 1 200~1 600 ℃. The flexural strength and the fracture toughness of the matrix materials were measured via three-point bending test and single-edge notch beam methods, respectively.Results:1) The particle distribution of the Al2O3/nZrO2 powder ranged from 0.02~3.0 μm, with the superfine particles almost accounting for 20%;2) There is a significant difference of flexural strength (P<0.05) between the groups with 1 450 ℃ and 1 600 ℃ sintering temperature and 1 200 ℃;3) There is a significant difference of flexural strength (P<0.05) between different zirconia volume fraction groups with the same sintering temperature, the ceramic matrix samples with higher nZrO2 (W) content had much better mechanical properties than those of pure α-Al2O3 ceramics.Conclusions:The studied nanometer α-Al2O3/nZrO2 powder was homogeously distributed within the matrix and had reasonable powder-size gradation to improve mechanical properties of ceramics.%目的:口腔全瓷修复体以其独特优越性受到医患青睐,但脆性问题一直限制其应用范围及使用可靠性.本研

  3. Investigation of Effects of Material Architecture on the Elastic Response of a Woven Ceramic Matrix Composite

    Science.gov (United States)

    Goldberg, Robert K.; Bonacuse, Peter J.; Mital, Subodh K.

    2012-01-01

    To develop methods for quantifying the effects of the microstructural variations of woven ceramic matrix composites on the effective properties and response of the material, a research program has been undertaken which is described in this paper. In order to characterize and quantify the variations in the microstructure of a five harness satin weave, CVI SiC/SiC, composite material, specimens were serially sectioned and polished to capture images that detailed the fiber tows, matrix, and porosity. Open source quantitative image analysis tools were then used to isolate the constituents and collect relevant statistics such as within ply tow spacing. This information was then used to build two dimensional finite element models that approximated the observed section geometry. With the aid of geometrical models generated by the microstructural characterization process, finite element models were generated and analyses were performed to quantify the effects of the microstructure and its variation on the effective stiffness and areas of stress concentration of the material. The results indicated that the geometry and distribution of the porosity appear to have significant effects on the through-thickness modulus. Similarly, stress concentrations on the outer surface of the composite appear to correlate to regions where the transverse tows are separated by a critical amount.

  4. Annual Conference on Composites and Advanced Ceramic Materials, 10th, Cocoa Beach, FL, January 19-24, 1986, Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1986-08-01

    The structures, performance characteristics, applications, and processing technology of ceramics, ceramic-matrix composites, and ceramic coatings are discussed in reviews and reports. Topics examined include ceramic-metal systems and self-propagating high-temperature synthesis, ceramics for heat engines and high performance, SiC-fiber and SiC-whisker composites, coatings, ceramic tribology, and cutting and grinding methods. Micrographs, graphs, photographs, and tables of numerical data are provided.

  5. Ceramic laser materials

    Science.gov (United States)

    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.

  6. New three-phase polymer-ceramic composite materials for miniaturized microwave antennas

    Science.gov (United States)

    Zhang, Li; Zhang, Jie; Yue, Zhenxing; Li, Longtu

    2016-09-01

    Unique polymer-ceramic composites for microwave antenna applications were prepared via melt extrusion using high-density polyethylene (HDPE) as the matrix and low-density polyethylene (LDPE) coated BaO-Nd2O3-TiO2 (BNT) ceramic-powders as the filler. By incorporating LDPE into the composites via a coating route, high ceramic-powder volume content (up to 50 vol%) could be achieved. The composites exhibited good microwave dielectric and thermomechanical behaviors. As BNT ceramic content increased from 10 vol% to 50 vol%, the permittivity of the composites increased from 3.45 (9 GHz) to 11.87 (7 GHz), while the dielectric loss remained lower than 0.0016. Microstrip antennas for applications in global positioning systems (GPS) were designed and fabricated from the composites containing 50 vol% BNT ceramics. The results indicate that the composites that have suitable permittivity and low dielectric loss are promising candidates for applications in miniaturized microwave devices, such as antennas.

  7. Shear bond strength between an indirect composite veneering material and zirconia ceramics after thermocycling.

    Science.gov (United States)

    Komine, Futoshi; Kobayashi, Kazuhisa; Saito, Ayako; Fushiki, Ryosuke; Koizumi, Hiroyasu; Matsumura, Hideo

    2009-12-01

    The present study evaluated the shear bond strength between an indirect composite material and zirconium dioxide (zirconia) ceramics after thermocycling. A total of 80 zirconia (Katana) discs were divided into five groups and primed with one of following agents: All Bond 2 Primer B (ABB), Alloy Primer (ALP), AZ Primer (AZP), Estenia Opaque Primer (EOP), and Porcelain Liner M Liquid A (PLA). An indirect composite material (Estenia C&B) was then bonded to the primed zirconia. One-half of the specimens (n = 8) in each group were stored in distilled water at 37 degrees C for 24 h, and the remaining eight specimens were thermocycled 5,000 times before shear bond strength testing. Mean bond strengths before thermocycling varied from 10.1 to 15.6 MPa; bond strengths after thermocycling ranged from 4.3 to 17.6 MPa. The ALP group had the highest strengths after thermocycling; there were no significant differences among the PLA, AZP, and EOP groups. The bond strength values for PLA, AZP, EOP, and ALP did not decrease with thermocycling. The application of an acidic functional monomer containing carboxylic anhydride (4-META), phosphonic acid (6-MHPA), or phosphate monomer (MDP) provided durable bond strength between Estenia C&B indirect composite and Katana zirconia.

  8. Ceramic materials and growth factors

    Energy Technology Data Exchange (ETDEWEB)

    Ohgushi, H.; Yoshikawa, T.; Okumura, M.; Nakajima, H.; Takakura, Y. [Nara Medical Univ. (Japan). Dept. of Orhtopaedic Surgery; Dohi, Y. [Nara Medical Univ. (Japan). Dept. of Public Health; Noshi, T.; Ikeuchi, M. [Nara Medical Univ. (Japan). Dept. of Oral and Maxillofacial Surgery

    2001-07-01

    Recently, many types of growth factors have been purified and used for promoting cell differentiation cascade. The activity of growth factors can be detected in vitro such as culture condition. However, the activity is difficult to detect when these factors are locally administered in vivo, because these dissipate soon after the administration. In order to retain growth factors in local milieu, these can be incorporated with biocompatible porous ceramic materials. Such ceramic/factors composites when implanted in vivo, can trigger certain types of cell differentiation cascade resulted in new tissue formation and tissue regeneration. The paper describes the ceramic / growth factors composites especially hydroxyapatite ceramic (HA) / bone morphogenetic protein (BMP) composite to induce osteoblastic differentiation of mesenchymal stem cells. The HA/BMP composite supported the osteoblastic differentiation on the HA surface and finally resulted in bone bonding to the HA. When the marrow mesenchymal stem cells (MSCs) were impregnated in pore areas of HA ceramics, the composites showed more and rapid bone formation than the HA/BMP and HA/MSCs composite, indicating the synergistic effect of BMP and MSCs. These findings indicate the importance of ceramic surface to evoke osteoblastic differentiation as well as to capture the molecules of growth factors for the cell differentiation. (orig.)

  9. Paper pulp waste—A new source of raw material for the synthesis of a porous ceramic composite

    Indian Academy of Sciences (India)

    Subrata Dasgupta; Swapan Kumar Das

    2002-10-01

    A synthetic porous ceramic composite material consisting of the mullite, cordierite and cristobalite phases is produced from a mixture of paper pulp waste and clay by reaction sintering at 1400°C. Physicomechanical properties such as bulk density, porosity, cold crushing strength and cold modulus of rupture have been studied. The presence of mullite, cordierite, cristobalite and quartz as major phases and montellecite, tatanite, forsterite and anorthite as minor phases have been confirmed by X-ray diffraction pattern. SEM studies revealed the presence of well developed needle shaped mullite and quartz crystals. The paper also discusses the possible uses of this type of porous composite material.

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

    Energy Technology Data Exchange (ETDEWEB)

    Steckenrider, J.S.; Ellingson, W.A. [Argonne National Lab., IL (United States); Rothermel, S.A. [South Dakota State Univ., Brookings, SD (United States)

    1995-05-01

    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{sub (f)}/SiC), SiC-fiber-reinforced silicon nitride (SiC {sub (f)}/Si{sub 3}N{sub 4}), aluminum oxide (Al{sub 2}O{sub 3})-fiber-reinforced Al{sub 2}O{sub 3} (Al{sub 2}O{sub 3}{sub (f)}/Al{sub 2}O{sub 3}), 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 has been used to examine the effects of thermal shock, oxidation treatment, density variations, and variations in oxidation resistant 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.

  11. Ceramic Composite Thin Films

    Science.gov (United States)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  12. Ceramic Laser Materials

    Energy Technology Data Exchange (ETDEWEB)

    Soules, T F; Clapsaddle, B J; Landingham, R L; Schaffers, K I

    2005-02-15

    Transparent ceramic materials have several major advantages over single crystals in laser applications, not the least of which is the ability to make large aperture parts in a robust manufacturing process. After more than a decade of working on making transparent YAG:Nd, Japanese workers have recently succeeded in demonstrating samples that performed as laser gain media as well as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. We have established a good working relationship with Konoshima Ltd., the Japanese producer of the best ceramic laser materials, and have procured and evaluated slabs designed by us for use in our high-powered SSHCL. Our measurements indicate that these materials will work in the SSHCL, and we have nearly completed retrofitting the SSHCL with four of the largest transparent ceramic YAG:Nd slabs in existence. We have also begun our own effort to make this material and have produced samples with various degrees of transparency/translucency. We are in the process of carrying out an extensive design-of-experiments to establish the significant process variables for making transparent YAG. Finally because transparent ceramics afford much greater flexibility in the design of lasers, we have been exploring the potential for much larger apertures, new materials, for example for the Mercury laser, other designs for SSHL, such as, edge pumping designs, slabs with built in ASE suppression, etc. This work has just beginning.

  13. Research & Development of Materials/Processing Methods for Continuous Fiber Ceramic Composites (CFCC) Phase 2 Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Szweda, A.

    2001-01-01

    The Department of Energy's Continuous Fiber Ceramic Composites (CFCC) Initiative that begun in 1992 has led the way for Industry, Academia, and Government to carry out a 10 year R&D plan to develop CFCCs for these industrial applications. In Phase II of this program, Dow Corning has led a team of OEM's, composite fabricators, and Government Laboratories to develop polymer derived CFCC materials and processes for selected industrial applications. During this phase, Dow Corning carried extensive process development and representative component demonstration activities on gas turbine components, chemical pump components and heat treatment furnace components.

  14. Influence of raw materials composition on firing shrinkage, porosity, heat conductivity and microstructure of ceramic tiles

    Science.gov (United States)

    Kurovics, E.; Buzimov, A. Y.; Gömze, L. A.

    2016-04-01

    In this work some new raw material compositions from alumina, conventional brick-clays and sawdust were mixed, compacted and heat treated by the authors. Depending on raw material compositions and firing temperatures the specimens were examined on shrinkage, water absorption, heat conductivity and microstructures. The real raised experiments have shown the important role of firing temperature and raw material composition on color, heat conductivity and microstructure of the final product.

  15. In vitro degradation and cell response of calcium carbonate composite ceramic in comparison with other synthetic bone substitute materials

    Energy Technology Data Exchange (ETDEWEB)

    He, Fupo [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Zhang, Jing [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Yang, Fanwen; Zhu, Jixiang; Tian, Xiumei [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Chen, Xiaoming, E-mail: xmchenw@126.com [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China)

    2015-05-01

    The robust calcium carbonate composite ceramics (CC/PG) can be acquired by fast sintering calcium carbonate at a low temperature (650 °C) using a biocompatible, degradable phosphate-based glass (PG) as sintering agent. In the present study, the in vitro degradation and cell response of CC/PG were assessed and compared with 4 synthetic bone substitute materials, calcium carbonate ceramic (CC), PG, hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics. The degradation rates in decreasing order were as follows: PG, CC, CC/PG, β-TCP, and HA. The proliferation of rat bone mesenchymal stem cells (rMSCs) cultured on the CC/PG was comparable with that on CC and PG, but inferior to HA and β-TCP. The alkaline phosphatase (ALP) activity of rMSCs on CC/PG was lower than PG, comparable with β-TCP, but higher than HA. The rMSCs on CC/PG and PG had enhanced gene expression in specific osteogenic markers, respectively. Compared to HA and β-TCP, the rMSCs on the CC/PG expressed relatively lower level of collagen I and runt-related transcription factor 2, but showed more considerable expression of osteopontin. Although CC, PG, HA, and β-TCP possessed impressive performances in some specific aspects, they faced extant intrinsic drawbacks in either degradation rate or mechanical strength. Based on considerable compressive strength, moderate degradation rate, good cell response, and being free of obvious shortcoming, the CC/PG is promising as another choice for bone substitute materials. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vitro degradation and cell response of CC/PG were compared to 4 materials. • The CC/PG showed moderate degradation rate. • The CC/PG exhibited good cell response. • The CC/PG was free of obvious drawback compared to other materials.

  16. Flash sintering of ceramic materials

    Science.gov (United States)

    Dancer, C. E. J.

    2016-10-01

    During flash sintering, ceramic materials can sinter to high density in a matter of seconds while subjected to electric field and elevated temperature. This process, which occurs at lower furnace temperatures and in shorter times than both conventional ceramic sintering and field-assisted methods such as spark plasma sintering, has the potential to radically reduce the power consumption required for the densification of ceramic materials. This paper reviews the experimental work on flash sintering methods carried out to date, and compares the properties of the materials obtained to those produced by conventional sintering. The flash sintering process is described for oxides of zirconium, yttrium, aluminium, tin, zinc, and titanium; silicon and boron carbide, zirconium diboride, materials for solid oxide fuel applications, ferroelectric materials, and composite materials. While experimental observations have been made on a wide range of materials, understanding of the underlying mechanisms responsible for the onset and latter stages of flash sintering is still elusive. Elements of the proposed theories to explain the observed behaviour include extensive Joule heating throughout the material causing thermal runaway, arrested by the current limitation in the power supply, and the formation of defect avalanches which rapidly and dramatically increase the sample conductivity. Undoubtedly, the flash sintering process is affected by the electric field strength, furnace temperature and current density limit, but also by microstructural features such as the presence of second phase particles or dopants and the particle size in the starting material. While further experimental work and modelling is still required to attain a full understanding capable of predicting the success of the flash sintering process in different materials, the technique non-etheless holds great potential for exceptional control of the ceramic sintering process.

  17. Multiscale Modeling of Ceramic Matrix Composites

    Science.gov (United States)

    Bednarcyk, Brett A.; Mital, Subodh K.; Pineda, Evan J.; Arnold, Steven M.

    2015-01-01

    Results of multiscale modeling simulations of the nonlinear response of SiC/SiC ceramic matrix composites are reported, wherein the microstructure of the ceramic matrix is captured. This micro scale architecture, which contains free Si material as well as the SiC ceramic, is responsible for residual stresses that play an important role in the subsequent thermo-mechanical behavior of the SiC/SiC composite. Using the novel Multiscale Generalized Method of Cells recursive micromechanics theory, the microstructure of the matrix, as well as the microstructure of the composite (fiber and matrix) can be captured.

  18. Structural properties of a bone-ceramic composite as a promising material in spinal surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kirilova, I. A., E-mail: IKirilova@mail.ru; Sadovoy, M. A.; Podorozhnaya, V. T., E-mail: VPodorognaya@niito.ru; Taranov, O. S. [Novosibirsk Research Institute of Traumatology and Orthopedics n.a. Ya.L. Tsivyan, Novosibirsk (Russian Federation); Klinkov, S. V.; Kosarev, V. F. [Christianovich Institute of Theoretical and Applied Mechanics, SB RAS, Novosibirsk (Russian Federation); Shatskaya, S. S. [Institute of Solid State Chemistry and Mechanochemistry, SB RAS, Novosibirsk (Russian Federation)

    2015-11-17

    The paper describes the results of in vitro tests of composite bone-ceramic implants and procedures for modifying implant surfaces to enhance osteogenesis. Analysis of CBCI ESs demonstrated that they have a porous structure with the mean longitudinal pore size of 70 µm and the mean transverse pore size of 46 µm; surface pores are open, while inner pores are closed. Elemental analysis of the CBCI surface demonstrates that CBCIs are composed of aluminum and zirconium oxides and contain HA inclusions. Profilometry of the CBCI ES surface revealed the following deviations: the maximum deviation of the profile in the sample center is 15 µm and 16 µm on the periphery, while the arithmetical mean and mean square deviations of the profile are 2.65 and 3.4 µm, respectively. In addition, CBCI biodegradation products were pre-examined; a 0.9% NaCl solution was used as a comparison group. Potentially toxic and tissue accumulated elements, such as cadmium, cobalt, mercury, and lead, are present only in trace amounts and have no statistically significant differences with the comparison group, which precludes their potential toxic effects on the macroorganism. Ceramic-based CBCI may be effective and useful in medicine for restoration of the anatomic integrity and functions of the bone tissue.

  19. Structural properties of a bone-ceramic composite as a promising material in spinal surgery

    Science.gov (United States)

    Kirilova, I. A.; Sadovoy, M. A.; Podorozhnaya, V. T.; Taranov, O. S.; Klinkov, S. V.; Kosarev, V. F.; Shatskaya, S. S.

    2015-11-01

    The paper describes the results of in vitro tests of composite bone-ceramic implants and procedures for modifying implant surfaces to enhance osteogenesis. Analysis of CBCI ESs demonstrated that they have a porous structure with the mean longitudinal pore size of 70 µm and the mean transverse pore size of 46 µm; surface pores are open, while inner pores are closed. Elemental analysis of the CBCI surface demonstrates that CBCIs are composed of aluminum and zirconium oxides and contain HA inclusions. Profilometry of the CBCI ES surface revealed the following deviations: the maximum deviation of the profile in the sample center is 15 µm and 16 µm on the periphery, while the arithmetical mean and mean square deviations of the profile are 2.65 and 3.4 µm, respectively. In addition, CBCI biodegradation products were pre-examined; a 0.9% NaCl solution was used as a comparison group. Potentially toxic and tissue accumulated elements, such as cadmium, cobalt, mercury, and lead, are present only in trace amounts and have no statistically significant differences with the comparison group, which precludes their potential toxic effects on the macroorganism. Ceramic-based CBCI may be effective and useful in medicine for restoration of the anatomic integrity and functions of the bone tissue.

  20. A new classification system for all-ceramic and ceramic-like restorative materials.

    Science.gov (United States)

    Gracis, Stefano; Thompson, Van P; Ferencz, Jonathan L; Silva, Nelson R F A; Bonfante, Estevam A

    2015-01-01

    Classification systems for all-ceramic materials are useful for communication and educational purposes and warrant continuous revisions and updates to incorporate new materials. This article proposes a classification system for ceramic and ceramic-like restorative materials in an attempt to systematize and include a new class of materials. This new classification system categorizes ceramic restorative materials into three families: (1) glass-matrix ceramics, (2) polycrystalline ceramics, and (3) resin-matrix ceramics. Subfamilies are described in each group along with their composition, allowing for newly developed materials to be placed into the already existing main families. The criteria used to differentiate ceramic materials are based on the phase or phases present in their chemical composition. Thus, an all-ceramic material is classified according to whether a glass-matrix phase is present (glass-matrix ceramics) or absent (polycrystalline ceramics) or whether the material contains an organic matrix highly filled with ceramic particles (resin-matrix ceramics). Also presented are the manufacturers' clinical indications for the different materials and an overview of the different fabrication methods and whether they are used as framework materials or monolithic solutions. Current developments in ceramic materials not yet available to the dental market are discussed.

  1. Glass and Glass-Ceramic Materials from Simulated Composition of Lunar and Martian Soils: Selected Properties and Potential Applications

    Science.gov (United States)

    Ray, C. S.; Sen, S.; Reis, S. T.; Kim, C. W.

    2005-01-01

    In-situ resource processing and utilization on planetary bodies is an important and integral part of NASA's space exploration program. Within this scope and context, our general effort is primarily aimed at developing glass and glass-ceramic type materials using lunar and martian soils, and exploring various applications of these materials for planetary surface operations. Our preliminary work to date have demonstrated that glasses can be successfully prepared from melts of the simulated composition of both lunar and martian soils, and the melts have a viscosity-temperature window appropriate for drawing continuous glass fibers. The glasses are shown to have the potential for immobilizing certain types of nuclear wastes without deteriorating their chemical durability and thermal stability. This has a direct impact on successfully and economically disposing nuclear waste generated from a nuclear power plant on a planetary surface. In addition, these materials display characteristics that can be manipulated using appropriate processing protocols to develop glassy or glass-ceramic magnets. Also discussed in this presentation are other potential applications along with a few selected thermal, chemical, and structural properties as evaluated up to this time for these materials.

  2. Metal-Matrix/Hollow-Ceramic-Sphere Composites

    Science.gov (United States)

    Baker, Dean M.

    2011-01-01

    A family of metal/ceramic composite materials has been developed that are relatively inexpensive, lightweight alternatives to structural materials that are typified by beryllium, aluminum, and graphite/epoxy composites. These metal/ceramic composites were originally intended to replace beryllium (which is toxic and expensive) as a structural material for lightweight mirrors for aerospace applications. These materials also have potential utility in automotive and many other terrestrial applications in which there are requirements for lightweight materials that have high strengths and other tailorable properties as described below. The ceramic component of a material in this family consists of hollow ceramic spheres that have been formulated to be lightweight (0.5 g/cm3) and have high crush strength [40.80 ksi (.276.552 MPa)]. The hollow spheres are coated with a metal to enhance a specific performance . such as shielding against radiation (cosmic rays or x rays) or against electromagnetic interference at radio and lower frequencies, or a material to reduce the coefficient of thermal expansion (CTE) of the final composite material, and/or materials to mitigate any mismatch between the spheres and the matrix metal. Because of the high crush strength of the spheres, the initial composite workpiece can be forged or extruded into a high-strength part. The total time taken in processing from the raw ingredients to a finished part is typically 10 to 14 days depending on machining required.

  3. Fibrous-Ceramic/Aerogel Composite Insulating Tiles

    Science.gov (United States)

    White, Susan M.; Rasky, Daniel J.

    2004-01-01

    Fibrous-ceramic/aerogel composite tiles have been invented to afford combinations of thermal-insulation and mechanical properties superior to those attainable by making tiles of fibrous ceramics alone or aerogels alone. These lightweight tiles can be tailored to a variety of applications that range from insulating cryogenic tanks to protecting spacecraft against re-entry heating. The advantages and disadvantages of fibrous ceramics and aerogels can be summarized as follows: Tiles made of ceramic fibers are known for mechanical strength, toughness, and machinability. Fibrous ceramic tiles are highly effective as thermal insulators in a vacuum. However, undesirably, the porosity of these materials makes them permeable by gases, so that in the presence of air or other gases, convection and gas-phase conduction contribute to the effective thermal conductivity of the tiles. Other disadvantages of the porosity and permeability of fibrous ceramic tiles arise because gases (e.g., water vapor or cryogenic gases) can condense in pores. This condensation contributes to weight, and in the case of cryogenic systems, the heat of condensation undesirably adds to the heat flowing to the objects that one seeks to keep cold. Moreover, there is a risk of explosion associated with vaporization of previously condensed gas upon reheating. Aerogels offer low permeability, low density, and low thermal conductivity, but are mechanically fragile. The basic idea of the present invention is to exploit the best features of fibrous ceramic tiles and aerogels. In a composite tile according to the invention, the fibrous ceramic serves as a matrix that mechanically supports the aerogel, while the aerogel serves as a low-conductivity, low-permeability filling that closes what would otherwise be the open pores of the fibrous ceramic. Because the aerogel eliminates or at least suppresses permeation by gas, gas-phase conduction, and convection, the thermal conductivity of such a composite even at

  4. Advanced Ceramic Materials for Future Aerospace Applications

    Science.gov (United States)

    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.

  5. Ceramics and ceramic matrix composites - Aerospace potential and status

    Science.gov (United States)

    Levine, Stanley R.

    1992-01-01

    Thermostructural ceramics and ceramic-matrix composites are attractive in numerous aerospace applications; the noncatastrophic fracture behavior and flaw-insensitivity of continuous fiber-reinforced CMCs renders them especially desirable. The present development status evaluation notes that, for most highly-loaded high-temperature applications, the requisite fiber-technology base is at present insufficient. In addition to materials processing techniques, the life prediction and NDE methods are immature and require a projection of 15-20 years for the maturity of CMC turbine rotors. More lightly loaded, moderate temperature aircraft engine applications are approaching maturity.

  6. Ceramic catalyst materials

    Energy Technology Data Exchange (ETDEWEB)

    Sault, A.G.; Gardner, T.J. [Sandia National Laboratories, Albuquerque, NM (United States); Hanprasopwattanna, A.; Reardon, J.; Datye, A.K. [Univ. of New Mexico, Albuquerque, NM (United States)

    1995-08-01

    Hydrous titanium oxide (HTO) ion-exchange materials show great potential as ceramic catalyst supports due to an inherently high ion-exchange capacity which allows facile loading of catalytically active transition metal ions, and an ability to be cast as thin films on virtually any substrate. By coating titania and HTO materials onto inexpensive, high surface area substrates such as silica and alumina, the economics of using these materials is greatly improved, particularly for the HTO materials, which are substantially more expensive in the bulk form than other oxide supports. In addition, the development of thin film forms of these materials allows the catalytic and mechanical properties of the final catalyst formulation to be separately engineered. In order to fully realize the potential of thin film forms of titania and HTO, improved methods for the deposition and characterization of titania and HTO films on high surface area substrates are being developed. By varying deposition procedures, titania film thickness and substrate coverage can be varied from the submonolayer range to multilayer thicknesses on both silica and alumina. HTO films can also be formed, but the quality and reproducibility of these films is not nearly as good as for pure titania films. The films are characterized using a combination of isopropanol dehydration rate measurements, point of zero charge (PZC) measurements, BET surface area, transmission electron microscopy (TEM), and elemental analysis. In order to assess the effects of changes in film morphology on catalytic activity, the films are being loaded with MoO{sub 3} using either incipient wetness impregnation or ion-exchange of heptamolybdate anions followed by calcining. The MoO{sub 3} is then sulfided to form MOS{sub 2}, and tested for catalytic activity using pyrene hydrogenation and dibenzothiophene (DBT) desulfurization, model reactions that simulate reactions occurring during coal liquefaction.

  7. JPRS Report, Science & Technology, USSR: Materials Science, Mechanics and Technology of Metal and Metal Ceramic Composite Material Products

    Science.gov (United States)

    1990-09-27

    produced, their phase composition and bending strength, as well as investigation of the promise of adding niobium carbide NbC to these materials. The...time increases, NbC does not inhibit shrink- niobium carbide was the same — 3 %. This content of age, which is a technological advantage. NbC is

  8. Standardisation of ceramic matrix composites

    Directory of Open Access Journals (Sweden)

    Gomez Philippe

    2015-01-01

    Full Text Available The standardisation on ceramic matrix composite (CMCs test methods occurred in the 1980's as these materials began to display interesting properties for aeronautical applications. Since the French Office of standardisation B43C has participated in establishing more than 40 standards and guides dealing with their thermal mechanical properties, their reinforcement and their fibre/matrix interface. As their maturity has been demonstrated through several technological development programmes (plugs, flaps, blades …, the air framers and engine manufacturers are now thinking of develop industrial parts which require a certification from airworthiness authorities. Now the standardisation of CMCs has to turn toward documents completing the certification requirement for civil and military applications. The news standards will allow being more confident with CMCs in taking into account their specificity.

  9. Metallic and intermetallic-bonded ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Plucknett, K.P.; Tiegs, T.N.; Alexander, K.B. [Oak Ridge National Laboratory, TN (United States)] [and others

    1995-05-01

    The purpose of this task is to establish a framework for the development and fabrication of metallic-phase-reinforced ceramic matrix composites with improved fracture toughness and damage resistance. The incorporation of metallic phases that plastically deform in the crack tip region, and thus dissipate strain energy, will result in an increase in the fracture toughness of the composite as compared to the monolithic ceramic. It is intended that these reinforced ceramic matrix composites will be used over a temperature range from 20{degrees}C to 800-1200{degrees}C for advanced applications in the industrial sector. In order to systematically develop these materials, a combination of experimental and theoretical studies must be undertaken.

  10. Annual Conference on Composites and Advanced Ceramic Materials, 13th, Cocoa Beach, FL, Jan. 15-18, 1989, Collection of Papers. Parts 1 2

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

    The present conference on advanced ceramics discusses topics in matrix-infiltration and processing techniques, the failure analysis of monolithic ceramics, the processing of polycrystalline oxide-matrix ceramic composites, the processing and properties of monolithic ceramics, ceramic composite interface phenomena, and ceramic NDE and characterization. Attention is given to chemical vapor infiltration for composites, dense ceramics via controlled melt oxidation, supertough silicon nitride, the properties of pressureless-sintered alumina-matrix/30 vol pct SiC composites, and toughening in metal particulate/glass-ceramic composites. Also discussed are the joining of silicon nitride for heat-engine applications, nitridation mechanisms in silicon powder compacts, the synthesis and properties of ceramic fibers, a technique for interfacial bond strength measurement, the degradation of SiC whiskers at elevated temperatures, and the correlation of NDE and fractography in Si3N4.

  11. Microwave sintering of ceramic materials

    Science.gov (United States)

    Karayannis, V. G.

    2016-11-01

    In the present study, the potential of microwave irradiation as an innovative energy- efficient alternative to conventional heating technologies in ceramic manufacturing is reviewed, addressing the advantages/disadvantages, while also commenting on future applications of possible commercial interest. Ceramic materials have been extensively studied and used due to several advantages they exhibit. Sintering ceramics using microwave radiation, a novel technology widely employed in various fields, can be an efficient, economic and environmentally-friendlier approach, to improve the consolidation efficiency and reduce the processing cycle-time, in order to attain substantial energy and cost savings. Microwave sintering provides efficient internal heating, as energy is supplied directly and penetrates the material. Since energy transfer occurs at a molecular level, heat is generated throughout the material, thus avoiding significant temperature gradients between the surface and the interior, which are frequently encountered at high heating rates upon conventional sintering. Thus, rapid, volumetric and uniform heating of various raw materials and secondary resources for ceramic production is possible, with limited grain coarsening, leading to accelerated densification, and uniform and fine-grained microstructures, with enhanced mechanical performance. This is particularly important for manufacturing large-size ceramic products of quality, and also for specialty ceramic materials such as bioceramics and electroceramics. Critical parameters for the process optimization, including the electromagnetic field distribution, microwave-material interaction, heat transfer mechanisms and material transformations, should be taken into consideration.

  12. Research Progress in Ceramic- Matrix Composite Materials%陶瓷基复合材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    王群; 刘欣; 李家科; 黄耀元; 周生娣

    2006-01-01

    综述了陶瓷基复合材料(ceramic matrix composite,CMC)的研究现状,对复合材料的补强增韧机理、界面、制备工艺作了较全面的介绍,并对CMC的未来发展进行了展望.

  13. Annual Conference on Composites and Advanced Ceramic Materials, 14th, Cocoa Beach, FL, Jan. 14-17, 1990, Collection of Papers. Parts 1 2

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    Attention is given to such topics as national goals in engineering ceramics, microstructural effects on the mechanical properties of monolithic ceramics, whisker-reinforced composites, and reaction-based processing. Processing-microstructure-property relations in fiber-reinforced ceramic matrix composites are also considered.

  14. Interphase for ceramic matrix composites reinforced by non-oxide ceramic fibers

    Science.gov (United States)

    DiCarlo, James A. (Inventor); Bhatt, Ramakrishna (Inventor); Morscher, Gregory N. (Inventor); Yun, Hee-Mann (Inventor)

    2008-01-01

    A ceramic matrix composite material is disclosed having non-oxide ceramic fibers, which are formed in a complex fiber architecture by conventional textile processes; a thin mechanically weak interphase material, which is coated on the fibers; and a non-oxide or oxide ceramic matrix, which is formed within the interstices of the interphase-coated fiber architecture. During composite fabrication or post treatment, the interphase is allowed to debond from the matrix while still adhering to the fibers, thereby providing enhanced oxidative durability and damage tolerance to the fibers and the composite material.

  15. Manufacturing of superconductive silver/ceramic composites

    DEFF Research Database (Denmark)

    Seifi, Behrouz; Bech, Jakob Ilsted; Eriksen, Morten

    2000-01-01

    Manufacturing of superconducting metal/ceramic composites is a rather new discipline within materials forming processes. High Temperature SuperConductors, HTSC, are manufactured applying the Oxide-Powder-In-Tube process, OPIT. A ceramic powder containing lead, calcium, bismuth, strontium......, and copper oxides is inserted into a silver tube and reduced by multi-step drawing. These single-filaments are packed in a new silver tube thus forming a multi-filament containing e.g. 37 single-filaments, which is subsequently reduced by drawing and rolling to tapes approximately 0.2 mm thick by 3 mm wide...

  16. Catalyzed Ceramic Burner Material

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Amy S., Dr.

    2012-06-29

    Catalyzed combustion offers the advantages of increased fuel efficiency, decreased emissions (both NOx and CO), and an expanded operating range. These performance improvements are related to the ability of the catalyst to stabilize a flame at or within the burner media and to combust fuel at much lower temperatures. This technology has a diverse set of applications in industrial and commercial heating, including boilers for the paper, food and chemical industries. However, wide spread adoption of catalyzed combustion has been limited by the high cost of precious metals needed for the catalyst materials. The primary objective of this project was the development of an innovative catalyzed burner media for commercial and small industrial boiler applications that drastically reduce the unit cost of the catalyzed media without sacrificing the benefits associated with catalyzed combustion. The scope of this program was to identify both the optimum substrate material as well as the best performing catalyst construction to meet or exceed industry standards for durability, cost, energy efficiency, and emissions. It was anticipated that commercial implementation of this technology would result in significant energy savings and reduced emissions. Based on demonstrated achievements, there is a potential to reduce NOx emissions by 40,000 TPY and natural gas consumption by 8.9 TBtu in industries that heavily utilize natural gas for process heating. These industries include food manufacturing, polymer processing, and pulp and paper manufacturing. Initial evaluation of commercial solutions and upcoming EPA regulations suggests that small to midsized boilers in industrial and commercial markets could possibly see the greatest benefit from this technology. While out of scope for the current program, an extension of this technology could also be applied to catalytic oxidation for volatile organic compounds (VOCs). Considerable progress has been made over the course of the grant

  17. Polymer - Ceramic Composites.

    Science.gov (United States)

    1988-04-01

    characteristic properties of our composite films are then compared with those of Piezel, a commercially available composite, manufactured by the Daikin Industry...S obtained on PIEZEL (composite of PZT and PVDF copolymer, supplied by Daikin Industries Limited of Japan) are also presented. 1% % .... . ,,, ,,,,~m

  18. Characterization of wear in composite material orthopaedic implants. Part I: The composite trunnion/ceramic head interface.

    Science.gov (United States)

    Maharaj, G; Bleser, S; Albert, K; Lambert, R; Jani, S; Jamison, R

    1994-01-01

    Carbon fiber reinforced polyetheretherketone (C/PEEK) composite materials are being investigated as an alternative to metal in the femoral component of a total hip arthroplasty. Wear is among the issues that must be addressed before introducing a new orthopaedic implant material. This study examines the generation of wear debris when zirconia femoral heads are mechanically attached to C/PEEK trunnions and loaded under simulated physiological conditions. Mechanical testing was performed on a trunnion/head assembly loaded from 445 to 4450N at an angle of 39 degrees to the long axis of the trunnion. The trunnions were tested at a frequency of 20 Hz for 10 million cycles. After completion of the fatigue test, solution from the test assembly was characterized by laser scattering and by SEM image analysis to determine the size, shape, total number, and identify of the particles. In addition, the peak load to pull the head from the trunnion was measured. The total number of particles generated during the test was in the range of 10(5) as indicated by both laser scattering and (SEM) image analysis. Both carbon fiber and PEEK particles were found in an average proportion of about 1:13, respectively. The carbon fiber particle size average was 153 microns and the PEEK particle size average was 2.2 microns. The zirconia heads remained well attached to the C/PEEK trunnions as indicated by a mean peak distraction force of 1942 +/- 116N.

  19. Colloidal forming of metal/ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Herencia, A.J.; Gutierrez, C.A.; Millan, A.J.; Nieto, M.I.; Moreno, R. [Inst. de Ceramica y Vidrio, Madrid (Spain)

    2002-07-01

    Metal/Ceramic composites have very attractive properties as either structural or electronic materials. For certain applications, complex microstructures and shapes are required. Colloidal processing of ceramics has proved to provide better properties and allows to obtain near net complex shaped parts. However colloidal processing has not received a similar attention in powder metallurgy. This work deals with the colloidal approach to the forming of metallic and metal/ceramic composites in an aqueous medium. Rheological behavior of concentrated pure nickel, nickel/alumina and nickel/zirconia suspensions is studied and optimized for obtaining flat surfaces or near net shaped parts by tape casting and gel casting respectively. In each case the influence of the processing additives (acrylic binders for tape casting and carrageenans for gel casting) on the rheological behavior of the slurries is determined. Pure nickel and nickel/ceramic composites with different compositions have been prepared. Static and dynamic sintering studies were performed at different conditions in order to control the porosity and microstructure of the final bodies, which were characterized by optical microscopy. (orig.)

  20. Nanostructured composite reinforced material

    Science.gov (United States)

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  1. Synergistically toughening effect of SiC whiskers and nanoparticles in Al2O3-based composite ceramic cutting tool material

    Science.gov (United States)

    Liu, Xuefei; Liu, Hanlian; Huang, Chuanzhen; Wang, Limei; Zou, Bin; Zhao, Bin

    2016-09-01

    In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiCnp advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vol% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730±95 MPa and fracture toughness is 5.6±0.6 MPa·m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.

  2. Synergistically toughening effect of SiC whiskers and nanoparticles in Al2O3-based composite ceramic cutting tool material

    Science.gov (United States)

    Liu, Xuefei; Liu, Hanlian; Huang, Chuanzhen; Wang, Limei; Zou, Bin; Zhao, Bin

    2016-06-01

    In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiCnp advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vol% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730±95 MPa and fracture toughness is 5.6±0.6 MPa·m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.

  3. Impact of Material and Architecture Model Parameters on the Failure of Woven Ceramic Matrix Composites (CMCs) via the Multiscale Generalized Method of Cells

    Science.gov (United States)

    Liu, Kuang C.; Arnold, Steven M.

    2011-01-01

    It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the effects of many of these architectural parameters and material scatter of woven ceramic composite properties at the macroscale (woven RUC) will be studied to assess their sensitivity. The recently developed Multiscale Generalized Method of Cells methodology is used to determine the overall deformation response, proportional elastic limit (first matrix cracking), and failure under tensile loading conditions. The macroscale responses investigated illustrate the effect of architectural and material parameters on a single RUC representing a five harness satin weave fabric. Results shows that the most critical architectural parameter is weave void shape and content with other parameters being less in severity. Variation of the matrix material properties was also studied to illustrate the influence of the material variability on the overall features of the composite stress-strain response.

  4. 陶瓷改性复合绝缘子材料的力学性能研究%Mechanical Properties of Composite Insulator Materials Modified by Ceramic

    Institute of Scientific and Technical Information of China (English)

    易春芳; 梁培松; 梁英; 刘云鹏

    2015-01-01

    In order to solve the treatment problem of a large number of retired ceramic insulator porcelain body every year, combining the advantages and chemical composition of ceramic insulators, we prepared a ceramic-modified composite insulator material using the powder of waste ceramic insulator porcelain body to modify silicone rubber. The effects of ceramic powder addition amount on the mechani-cal properties of the silicone rubber were studied by testing the tensile strength, tear strength, and hardness of the modified silicone rubber and SEM and Fourier transform infrared spectroscopy analysis. The results show that a proportion of the ceramic powder can replace part of aluminum hydroxide powder and fumed silica powder, and it can improve the mechanical properties of the silicone rubber significantly.%为解决每年大量退运陶瓷绝缘子的瓷体处理问题,结合陶瓷绝缘子的优点及其化学成分,利用废旧陶瓷绝缘子瓷体研磨成粉末后改性硅橡胶而制得陶瓷改性复合绝缘子材料,通过测试改性硅橡胶的拉伸强度、撕裂强度和硬度,并利用SEM电镜扫描及红外光谱进行分析,对比研究了陶瓷粉添加量对硅橡胶力学性能的影响。结果表明:一定比例的陶瓷粉可以替代部分氢氧化铝微粉和气相法白炭黑,且对硅橡胶的力学性能有明显的改善。

  5. Updating Classifications of Ceramic Dental Materials: A Guide to Material Selection.

    Science.gov (United States)

    McLaren, Edward A; Figueira, Johan

    2015-06-01

    The indications for and composition of today's dental ceramic materials serve as the basis for determining the appropriate class of ceramics to use for a given case. By understanding the classifications, composition, and characteristics of the latest all-ceramic materials, which are presented in this article in order of most to least conservative, dentists and laboratory technicians can best determine the ideal material for a particular treatment.

  6. Composite Materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    This book deals with the mechanical and physical behavior of composites as influenced by composite geometry. "Composite Materials" provides a comprehensive introduction for researchers and students to modern composite materials research with a special emphasis on the significance of phase geometry....... The book enables the reader to a better understanding of the behavior of natural composites, improvement of such materials, and design of new materials with prescribed properties. A number of examples are presented: Special composite properties considered are stiffness, shrinkage, hygro-thermal behavior......, viscoelastic behavior, and internal stress states. Other physical properties considered are thermal and electrical conductivities, diffusion coefficients, dielectric constants and magnetic permeability. Special attention is given to the effect of pore shape on the mechanical and physical behavior of porous...

  7. Passive Vibration Damping Materials: Piezoelectric Ceramic Composites for Vibration Damping Applications

    Science.gov (United States)

    1994-02-01

    Augmentation Awards for Science and Engineering Research Training) support, a student has been looking into the effects of additives and the...with some material deformation, which is not physicall ,. tional references to other pertinent work. The following para- ble. This analysis used a non...and the National Science Founuation cluding small, 1r-mm diam, PZT tubes) have been reported in the literature[1"-41 No fine-scale resistively

  8. Characterization of Mechanical Damage Mechanisms in Ceramic and Polymeric Matrix Composite Materials

    Science.gov (United States)

    1992-12-01

    whole or in part is permitted for any purpose of the United Sates Government SOUTHWEST RESEARCH INSTITUTE SAN ANTONIO HOUSTON DETROIT WASH INGTO1N...materials. Specimen Design Cylindrical specimens 1.2 cm long x 0.6 cm diameter, with a slightly reduced midsection (Figure 1), were machined from sample...flow region, the pressure-induced changes in overall inelastic deformation will greatly dominate any changes in the virtually microplastic flow

  9. Tailoring of unipolar strain in lead-free piezoelectrics using the ceramic/ceramic composite approach

    Energy Technology Data Exchange (ETDEWEB)

    Khansur, Neamul H.; Daniels, John E. [School of Materials Science and Engineering, University of New South Wales, NSW 2052 (Australia); Groh, Claudia; Jo, Wook; Webber, Kyle G. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Reinhard, Christina [Diamond Light Source, Beamline I12 JEEP, Didcot, Oxfordshire OX11 0DE (United Kingdom); Kimpton, Justin A. [The Australian Synchrotron, Clayton, Victoria 3168 (Australia)

    2014-03-28

    The electric-field-induced strain response mechanism in a polycrystalline ceramic/ceramic composite of relaxor and ferroelectric materials has been studied using in situ high-energy x-ray diffraction. The addition of ferroelectric phase material in the relaxor matrix has produced a system where a small volume fraction behaves independently of the bulk under an applied electric field. Inter- and intra-grain models of the strain mechanism in the composite material consistent with the diffraction data have been proposed. The results show that such ceramic/ceramic composite microstructure has the potential for tailoring properties of future piezoelectric materials over a wider range than is possible in uniform compositions.

  10. Comparison of Reactive and Non-Reactive Spark Plasma Sintering Routes for the Fabrication of Monolithic and Composite Ultra High Temperature Ceramics (UHTC Materials

    Directory of Open Access Journals (Sweden)

    Roberto Orrù

    2013-04-01

    Full Text Available A wider utilization of ultra high temperature ceramics (UHTC materials strongly depends on the availability of efficient techniques for their fabrication as dense bodies. Based on recent results reported in the literature, it is possible to state that Spark Plasma Sintering (SPS technology offers a useful contribution in this direction. Along these lines, the use of two different SPS-based processing routes for the preparation of massive UHTCs is examined in this work. One method, the so-called reactive SPS (R-SPS, consists of the synthesis and densification of the material in a single step. Alternatively, the ceramic powders are first synthesized by Self-propagating High-temperature Synthesis (SHS and then sintered by SPS. The obtained results evidenced that R-SPS method is preferable for the preparation of dense monolithic products, while the sintering of SHS powders requires relatively milder conditions when considering binary composites. The different kinetic mechanisms involved during R-SPS of the monolithic and composite systems, i.e., combustion-like or gradual solid-diffusion, respectively, provides a possible explanation. An important role is also played by the SHS process, particularly for the preparation of composite powders, since stronger interfaces are established between the ceramic constituents formed in situ, thus favoring diffusion processes during the subsequent SPS step.

  11. Nanocrystalline ceramic materials

    Science.gov (United States)

    Siegel, Richard W.; Nieman, G. William; Weertman, Julia R.

    1994-01-01

    A method for preparing a treated nanocrystalline metallic material. The method of preparation includes providing a starting nanocrystalline metallic material with a grain size less than about 35 nm, compacting the starting nanocrystalline metallic material in an inert atmosphere and annealing the compacted metallic material at a temperature less than about one-half the melting point of the metallic material.

  12. Fundamental alloy design of oxide ceramics and their composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, I.W.

    1992-01-01

    The main research was on microstructural development of oxide ceramics. Projects were completed and the publications given. Abstracts are given on: Reactive CeO[sub 2]powders by homogeneous precipitation, SiC whisker-reinforced lithium aluminosilicate composite, solute drag on grain boundary in ionic solids (space charge effect), in-situ alumina/aluminate platelet composites, exaggerated texture and grain growth of superplastic silicon nitride (SiAlON), hot extrusion of ceramics, control of grain boundary pinning in Al[sub 2]O[sub 3]/ZrO[sub 2] composites with Ce[sup 3+]/Ce[sup 4+] doping, superplastic forming of ceramic composites, computer simulation of final stage sintering (model, kinetics, microstructure, effect of initial pore size), development of superplastic structural ceramics, and superplastic flow of two-phase ceramics containing rigid inclusions (zirconia/mullite composites). A proposed research program is outlined: materials, solute drag, densification and coarsening, and grain boundary electrical behavior.

  13. Nanocrystalline ceramic materials

    Science.gov (United States)

    Siegel, R.W.; Nieman, G.W.; Weertman, J.R.

    1994-06-14

    A method is disclosed for preparing a treated nanocrystalline metallic material. The method of preparation includes providing a starting nanocrystalline metallic material with a grain size less than about 35 nm, compacting the starting nanocrystalline metallic material in an inert atmosphere and annealing the compacted metallic material at a temperature less than about one-half the melting point of the metallic material. 19 figs.

  14. Ceramic materials testing and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Wilfinger, K. R., LLNL

    1998-04-30

    corrosion by limiting the transport of water and oxygen to the ceramic-metal interface. Thermal spray techniques for ceramic coating metallic structures are currently being explored. The mechanics of thermal spray resembles spray painting in many respects, allowing large surfaces and contours to be covered smoothly. All of the relevant thermal spray processes use a high energy input to melt or partially melt a powdered oxide material, along with a high velocity gas to impinge the molten droplets onto a substrate where they conform, quench, solidify and adhere mechanically. The energy input can be an arc generated plasma, an oxy-fuel flame or an explosion. The appropriate feed material and the resulting coating morphologies vary with technique as well as with application parameters. To date on this project, several versions of arc plasma systems, a detonation coating system and two variations of high velocity oxy-fuel (HVOF) fired processes have been investigated, operating on several different ceramic materials.

  15. Effects of sintering processes on mechanical properties and microstructure of TiB{sub 2}-TiC + 8 wt% nano-Ni composite ceramic cutting tool material

    Energy Technology Data Exchange (ETDEWEB)

    Zou Bin, E-mail: zou20011110@163.com [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China) and Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Shandong University, Ministry of Education (China); Huang Chuanzhen; Song Jinpeng; Liu Ziye; Liu Lin; Zhao Yan [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Key Laboratory of High Efficiency and Clean Mechanical Manufacture (Shandong University), Ministry of Education (China)

    2012-04-01

    Highlights: Black-Right-Pointing-Pointer TiB{sub 2}-TiC + 8 wt% nano-Ni ceramic tool material was sintered by six processes. Black-Right-Pointing-Pointer The properties of material depended mainly on the holding stages and duration. Black-Right-Pointing-Pointer SP1 process was involved with the multiple holding stages and longer duration. Black-Right-Pointing-Pointer SP1 process led to many pores, and coarsening and brittle rupture of grains. Black-Right-Pointing-Pointer Tool material sintered by SP6 process exhibited the optimum mechanical properties. - Abstract: TiB{sub 2}-TiC composite powder was prepared by ball-milled with ethanol and vacuum dry, and TiB{sub 2}-TiC + 8 wt% nano-Ni composite ceramic cutting tool material was sintered using vacuum hot-pressed sintering technique by six processes which included the different holding stages and times. The effects of sintering processes on the mechanical properties and microstructure were investigated. The polished surface and fracture surface of TiB{sub 2}-TiC + 8 wt% nano-Ni ceramics sintered by the different sintering processes were observed by scanning electron microscope (SEM), X-ray diffraction (XRD) and energy-dispersive spectrometry (EDS), and the relationships between mechanical properties and microstructure were discussed. The mechanical properties and microstructure depended mainly on the total holding time and the different holding stages. The longer holding time and multiple holding stages led to coarsening of TiB{sub 2} and TiC grains, formation of pores and the brittle rupture of grains, which deteriorated the mechanical properties of TiB{sub 2}-TiC + 8 wt% nano-Ni ceramic. TiB{sub 2}-TiC + 8 wt% nano-Ni composite ceramic cutting tool material sintered by SP6 process exhibited the optimum resultant mechanical properties because of its finer microstructure and higher relative density, and its flexural strength, fracture toughness and hardness were 916.8 MPa, 7.80 MPa m{sup 1/2} and 22.54 GPa

  16. Ferrites and ceramic composites

    CERN Document Server

    Jotania, Rajshree B

    2013-01-01

    The Ferrite term is used to refer to all magnetic oxides containing iron as major metallic component. Ferrites are very attractive materials because they simultaneously show high resistivity and high saturation magnetization, and attract now considerable attention, because of the interesting physics involved. Typical ferrite material possesses excellent chemical stability, high corrosion resistivity, magneto-crystalline anisotropy, magneto-striction, and magneto-optical properties. Ferrites belong to the group of ferrimagnetic oxides, and include rare-earth garnets and ortho-ferrites. Several

  17. Composite material

    Science.gov (United States)

    Hutchens, Stacy A.; Woodward, Jonathan; Evans, Barbara R.; O'Neill, Hugh M.

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  18. The application of composite ceramic materials market development is the subject of future new%复合陶瓷的应用发展是未来新材料市场的主题

    Institute of Scientific and Technical Information of China (English)

    朱则刚

    2012-01-01

    Ceramic matrix composites is not a traditional ceramics, it is a ceramic fiber matrix with a variety of a class of composite materials. Its main base glass ceramics, alumina, silicon nitride, etc. , with high-temperature strength, high wear resistance, high corrosion resistance, low thermal expansion coefficient, good heat insulation properties and low density, etc. , but rich in resources, A wide range of applications. Ceramic matrix composites for a competition for the commanding heights of th plain e mt ernational market, analyzes the development of ceramic matrix composites attention to excharacteristics of the composite ceramic materials, ceramic matrix composite materials are introduced in the application areas, noting that the energy saving ceramic car Matrix structural composite accomplish much.%陶瓷基复合材料不是传统意义上的陶瓷,它是以陶瓷为基体与各种纤维复合的一类复合材料。其主要基体有玻璃陶瓷、氧化铝、氮化硅等,具有高温强度好、高耐磨性、高耐腐蚀性、低膨胀系数、隔热性好及低密度等特性,而且资源也比较丰富,有广泛的应用前景。针对陶瓷基复合材料成为争夺国际市场的制高点,分析了陶瓷基复合材料的研发受到重视,阐述了复合陶瓷材料的特点,介绍了陶瓷基复合材料的应用领域,同时指出了节能环保的车用陶瓷基结构复合材料大有作为。

  19. The application of composite ceramic materials market development is the subject of future new%复合陶瓷的应用发展是未来新材料市场的主题

    Institute of Scientific and Technical Information of China (English)

    朱则刚

    2012-01-01

    Ceramic matrix composites is not a traditional ceramics, it is a ceramic fiber matrix with a variety of a class of composite materials. Its main base glass ceramics, alumina, silicon nitride, etc. , with high -temperature strength, high wear resistance, high corrosion resistance, low thermal expansion coefficient, good heat insulation properties and low density, etc. , but rich in resources, A wide range of applications. Ceramic matrix composites for a competition for the commanding heights of the international market, analyzes the development of ceramic matrix composites attention to explain the characteristics of the composite ceramic materials, ceramic matrix composite materials are introduced in the application areas, noting that the energy saving ceramic car Matrix structural composite accomplish much.%陶瓷基复合材料不是传统意义上的陶瓷,它是以陶瓷为基体与各种纤维复合的一类复合材料。其主要基体有玻璃陶瓷、氧化铝、氮化硅等,具有高温强度好、高耐磨性、高耐腐蚀性、低膨胀系数、隔热性好及低密度等特性,而且资源也比较丰富,有广泛的应用前景。针对陶瓷基复合材料成为争夺国际市场的制高点,分析了陶瓷基复合材料的研发受到重视,阐述了复合陶瓷材料的特点,介绍了陶瓷基复合材料的应用领域,同时指出了节能环保的车用陶瓷基结构复合材料大有作为。

  20. Preparation and Easy-Cleaning Property of Rare Earth Composite Ceramic

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Rare earth and far-infrared mineral composite materials were added to ceramic glazes to prepare easy-cleaning ceramic. The morphology of easy-cleaning ceramic was observed by SEM. The influence of easy-cleaning ceramic on water surface tension and contact angles of water were investigated. Through calculation of ceramic surface free energy and observation of oil drop on ceramic surface in water, the easy-cleaning mechanism of rare earth composite ceramic was studied. It is found that the rare earth composite ceramic can make water surface tension decrease. The surface free energy and the polar component of rare earth composite ceramic are increased. The rare earth composite ceramics have the easy-cleaning property.

  1. Biotechnology and Composite Materials

    Science.gov (United States)

    1993-04-01

    Biotechnology, in general terms, is the science and engineering of using living organisms for making useful products such as pharmaceuticals, foods , fuels...chemicals, materials or in waste treatment processes and clinical and chemical analyses. It encompases the prosaic form of using yeast cells to make...ductile component of the composite. Table 1. Mechanical Properties of Ceramics, Cermets, and Abalone Shell •if KIC Hardness MPa MPam 1n 2 /2 Mohs KIlN

  2. Surface modification of ceramic matrix composites induced by laser treatment

    Science.gov (United States)

    Costil, S.; Lukat, S.; Langlade, C.; Coddet, C.

    2008-12-01

    Ceramics or ceramic composites present many advantages (hardness, chemical resistance, low density, etc.) which induce some more and more important applications particularly from the industrial point of view. The evolution of technology can also be beneficial to enlarge their global application areas. This is particularly the aim of this work which consists in applying a laser beam on the ceramic in order to clean its surface. A Nd:YAG laser has been used to study the basic mechanism roughening the surface of silicon carbide composite (ceramic matrix composite (CMC)). Investigations on different surfaces (two chemical compositions) show a strong influence of the nature of the material on the development of a characteristic conic structure. Microscopic studies (SEM) and elementary analyses (EDS and RMS) demonstrated the formation of a regular cone-like structure with a kinetic and a chemical modification specific to each material.

  3. Structural Ceramic Composites for Nuclear Applications

    Energy Technology Data Exchange (ETDEWEB)

    William Windes; P.A. Lessing; Y. Katoh; L. L. Snead; E. Lara-Curzio; J. Klett; C. Henager, Jr.; R. J. Shinavski

    2005-08-01

    A research program has been established to investigate fiber reinforced ceramic composites to be used as control rod components within a Very High Temperature Reactor. Two candidate systems have been identified, carbon fiber reinforced carbon (Cf/C) and silicon carbide fiber reinforced silicon carbide (SiCf/SiC) composites. Initial irradiation stability studies to determine the maximum dose for each composite type have been initiated within the High Flux Isotope Reactor at Oak Ridge National Laboratory. Test samples exposed to 10 dpa irradiation dose have been completed with future samples to dose levels of 20 and 30 dpa scheduled for completion in following years. Mechanical and environmental testing is being conducted concurrently at the Idaho National Laboratory and at Pacific Northwest National Laboratory. High temperature test equipment, testing methodologies, and test samples for high temperature (up to 1600º C) tensile strength and long duration creep studies have been established. Specific attention was paid to the architectural fiber preform design as well as the materials used in construction of the composites. Actual testing of both tubular and flat, "dog-bone" shaped tensile composite specimens will begin next year. Since there is no precedence for using ceramic composites within a nuclear reactor, ASTM standard test procedures will be established from these mechanical and environmental tests. Close collaborations between the U.S. national laboratories and international collaborators (i.e. France and Japan) are being forged to establish both national and international test standards to be used to qualify ceramic composites for nuclear reactor applications.

  4. Emerging Ceramic-based Materials for Dentistry

    Science.gov (United States)

    Denry, I.; Kelly, J.R.

    2014-01-01

    Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appropriate, the authors have added their opinions and guidance. PMID:25274751

  5. Attachment of epithelial cells and fibroblasts to ceramic materials.

    Science.gov (United States)

    Niederauer, G G; McGee, T D; Keller, J C; Zaharias, R S

    1994-04-01

    This study examined in vitro gingival epithelial and fibroblast cell attachment to ceramic materials made of tricalcium phosphate and/or magnesium aluminate spinel. The composite made of tricalcium phosphate and spinel is called 'osteoceramic'. These ceramics had various compositions and surface structures, which were initially characterized. Cell attachment assays were performed using both cell types to compare cellular response to the ceramic materials. Specimens were also prepared for scanning electron microscopy to investigate cellular morphology. The highest levels of cell attachment for gingival epithelial cells were observed on the rough osteoceramic surface, whereas gingival fibroblasts attached least to the rough osteoceramic surface.

  6. Improved Internal Reference Oxygen Sensors with Composite Ceramic Electrodes

    DEFF Research Database (Denmark)

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

    2012-01-01

    Potentiometric oxygen sensors with an internal reference electrode, which uses the equilibrium pO2 of the binary mixture of Ni/NiO as the reference, are demonstrated. The cells employ Pt or composite ceramics as the sensing electrode. The cells are fabricated by a flexible and potentially low cost...... and performance are highly reproducible. The composite ceramics, based on strontium doped manganite and yttria doped zirconia, are proven superior over Pt to serve as the electrode material....

  7. A review of ceramic bearing materials in total joint arthroplasty.

    Science.gov (United States)

    Bal, B S; Garino, J; Ries, M; Rahaman, M N

    2007-01-01

    Bearings made of ceramics have ultra-low wear properties that make them suitable for total hip arthroplasty (THA) and total knee arthroplasty (TKA). When compared to cobalt chrome (CoCr)-on-polyethylene (PE) articulations, ceramics offer drastic reductions in bearing wear rates. Lower wear rates result in fewer wear particles produced by the articulating surfaces. In theory, this should reduce the risk of periprosthetic osteolysis and premature implant loosening, thereby contributing to the longevity of total joints. In addition to ceramics, other alternative bearing couples, such as highly cross-linked PE (XLPE) and metal-on-metal also offer less wear than CoCr-on-PE articulations in total joint arthroplasty. Alumina and zirconia ceramics are familiar to orthopaedic surgeons since both materials have been used in total joints for several decades. While not new in Europe, alumina-on-alumina ceramic total hips have only recently become available for widespread use in the United States from various orthopaedic implant manufacturers. As the search for the ideal total joint bearing material continues, composite materials of existing ceramics, metal-on-ceramic articulations, and new ceramic technologies will offer more choices to the arthroplasty surgeon. The objective of this paper is to present an overview of material properties, clinical applications, evolution, and limitations of ceramic materials that are of interest to the arthroplasty surgeon.

  8. Intermetallic bonded ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Plucknett, K.P.; Tiegs, T.N.; Alexander, K.B.; Becher, P.F.; Schneibel, J.H.; Waters, S.B.; Menchhofer, P.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1995-07-01

    A range of carbide and oxide-based cermets have been developed utilizing ductile nickel aluminide (Ni{sub 3}Al) alloy binder phases. Some of these, notably materials based upon tungsten and titanium carbides (WC and TiC respectively), offer potential as alternatives to the cermets which use cobalt binders (i.e. WC/Co). Samples have been prepared by blending commercially available Ni{sub 3}Al alloy powders with the desired ceramic phases, followed by hot-pressing. Alumina (Al{sub 2}O{sub 3}) matrix materials have also been prepared by pressurized molten alloy infiltration. The microstructure, flexure strength and fracture toughness of selected materials are discussed.

  9. Ceramics As Materials Of Construction

    OpenAIRE

    Zaki, A.; Eteiba, M. B.; Abdelmonem, N.M.

    1988-01-01

    This paper attempts to review the limitations for using the important ceramics in contact with corrosive media. Different types of ceramics are included. Corrosion properties of ceramics and their electrical properties are mentioned. Recommendations are suggested for using ceramics in different media.

  10. Use of the Materials Genome Initiative (MGI approach in the design of improved-performance fiber-reinforced SiC/SiC ceramic-matrix composites (CMCs

    Directory of Open Access Journals (Sweden)

    Jennifer S. Snipes

    2016-07-01

    Full Text Available New materials are traditionally developed using costly and time-consuming trial-and-error experimental efforts. This is followed by an even lengthier material-certification process. Consequently, it takes 10 to 20 years before a newly-discovered material is commercially employed. An alternative approach to the development of new materials is the so-called materials-by-design approach within which a material is treated as a complex hierarchical system, and its design and optimization is carried out by employing computer-aided engineering analyses, predictive tools and available material databases. In the present work, the materials-by-design approach is utilized to design a grade of fiber-reinforced (FR SiC/SiC ceramic matrix composites (CMCs, the type of materials which are currently being used in stationary components, and are considered for use in rotating components, of the hot sections of gas-turbine engines. Towards that end, a number of mathematical functions and numerical models are developed which relate CMC constituents’ (fibers, fiber coating and matrix microstructure and their properties to the properties and performance of the CMC as a whole. To validate the newly-developed materials-by-design approach, comparisons are made between experimentally measured and computationally predicted selected CMC mechanical properties. Then an optimization procedure is employed to determine the chemical makeup and processing routes for the CMC constituents so that the selected mechanical properties of the CMCs are increased to a preset target level.

  11. Materials characteristics of uncoated/ceramic-coated implant materials.

    Science.gov (United States)

    Lacefield, W R

    1999-06-01

    In this paper, the biocompatibility of dental implant materials is discussed in the context of both the mechanical characteristics of the materials and the type of surface presented to the surrounding tissues. The proper functioning of the implant depends on whether it possesses the strength necessary to withstand loading within the expected range, with other properties such as elongation being of importance in some instances. A suitable modulus of elasticity may be of major importance in situations when optimum load transmission from the implant into the surrounding bone is key to the successful functioning of the device. Dental implants present a wide range of surfaces to the surrounding tissues based on surface composition, texture, charge energy, and cleanliness (sterility). Metallic implants are characterized by protective oxide layers, but ion release is still common with these materials, and is a function of passivation state, composition, and corrosion potential. An effective surface treatment for titanium appears to be passivation or anodization in a suitable solution prior to implantation. Inert ceramic surfaces exhibit minimal ion release, but are similar to metals in that they do not form a high energy bond to the surrounding bone. Some of the newly developed dental implant alloys such as titanium alloys, which contain zirconium and niobium, and high-strength ceramics such as zirconia may offer some advantages (such as lower modulus of elasticity) over the conventional materials. Calcium phosphate ceramic coatings are commonly used to convert metallic surfaces into a more bioactive state and typically cause faster bone apposition. There is a wide range of ceramic coatings containing calcium and phosphorus, with the primary difference in many of these materials being in the rate of ion release. Although their long-term success rate is unknown, the calcium phosphate surfaces seem to have a higher potential for attachment of osteoinductive agents than do

  12. Development and characterization of Textron continuous fiber ceramic composite hot gas filter materials. Final report, September 30, 1994--October 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    DiPietro, S.G.; Alvin, M.A.

    1997-12-31

    Uncertainties about the long-term ability of monolithic ceramics to survive in the IGCC or PFBC hot gas filter environment led DOE/METC to consider the merits of using continuous fiber reinforced ceramic composites (CFCCs) as potential next-generation high temperature filter elements. This seems to be a logical strategy to pursue in light of the fact that properly-engineered CFCC materials have shown much-improved damage tolerance and thermal shock behavior as compared to existing monolithic ceramic materials. Textron`s Advanced Hot Gas Filter Development Program was intended to be a two year, two phase program which transitioned developmental materials R and D into prototype filter element fabrication. The first phase was to demonstrate the technical feasibility of fabricating CFCC hot gas filter elements which could meet the pressure drop specifications of less than ten inches of water (iwg) at a face velocity of ten feet per minute (fpm), while showing sufficient integrity to survive normal mechanical loads and adequate environmental resistance to steam/alkali corrosion conditions at a temperature of approximately 870 C (1600 F). The primary objective of the second phase of the program was to scale up fabrication methods developed in Phase 1 to produce full-scale CFCC candle filters for validation testing. Textron encountered significant process-related and technical difficulties in merely meeting the program permeability specifications, and much effort was expended in showing that this could indeed be achieved. Thus, by the time the Phase 1 program was completed, expenditure of program funds precluded continuing on with Phase 2, and Textron elected to terminate their program after Phase 1. This allowed Textron to be able to focus technical and commercialization efforts on their largely successful DOE CFCC Program.

  13. Continuous Fiber Ceramic Composite (CFCC) Program: Gaseous Nitridation

    Energy Technology Data Exchange (ETDEWEB)

    R. Suplinskas G. DiBona; W. Grant

    2001-10-29

    Textron has developed a mature process for the fabrication of continuous fiber ceramic composite (CFCC) tubes for application in the aluminum processing and casting industry. The major milestones in this project are System Composition; Matrix Formulation; Preform Fabrication; Nitridation; Material Characterization; Component Evaluation

  14. Characterization of CVI densification of ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Starr, T.L.; Stock, S.R.; Lee, S. [Georgia Institute of Technology, Atlanta, GA (United States)

    1995-05-01

    Ceramic matrix composites promise higher operating temperature and better thermodynamic efficiency in many enregy conversion systems. In particular, composites fabricated by the chemical vapor infiltration (CVI) process have excellent mechanical properties and, using the forced flow-thermal gradient variation, good processing economics in small scale demonstrations. Scale-up to larger, more complex shapes requires understanding of gas flow through the fiber preform and of the relationship between fiber architecture and densification behavior. This understanding is needed for design of preforms for optimum infiltration. The objective of this research is to observe the deposition of matrix material in the pores of a ceramic fiber preform at various stages of the CVI process. These observations allow us to relate local deposition rates in various regions of the composite to the connectivity of the surrounding network of porosity and to better model the relationship between gas transport and fiber architecture in CVI preforms. Our observation of the CVI process utilizes high resolution X-ray tomographic microscopy (XTM) in collaboration with Dr. John Kinney at Lawrence Livermore National Laboratory with repeated imaging of a small preform specimens after various processing times. We use these images to determine geometry and dimensions of channels between and through layers in cloth lay-up preform during CVI densification and relate these to a transport model.

  15. Effect of surface treatments on shear bond strength of resin composite bonded to CAD/CAM resin-ceramic hybrid materials

    Science.gov (United States)

    Güngör, Merve Bankoğlu; Bal, Bilge Turhan; Ünver, Senem; Doğan, Aylin

    2016-01-01

    PURPOSE The purpose of this study was to assess the effect of surface treatments on shear bond strength of resin composite bonded to thermocycled and non-thermocycled CAD/CAM resin-ceramic hybrid materials. MATERIALS AND METHODS 120 specimens (10×10×2 mm) from each material were divided into 12 groups according to different surface treatments in combination with thermal aging procedures. Surface treatment methods were airborne-particle abrasion (abraded with 50 micron alumina particles), dry grinding (grinded with 125 µm grain size bur), and hydrofluoric acid (9%) and silane application. According to the thermocycling procedure, the groups were assigned as non-thermocycled, thermocycled after packing composites, and thermocycled before packing composites. The average surface roughness of the non-thermocycled specimens were measured after surface treatments. After packing composites and thermocycling procedures, shear bond strength (SBS) of the specimens were tested. The results of surface roughness were statistically analyzed by 2-way Analysis of Variance (ANOVA), and SBS results were statistically analyzed by 3-way ANOVA. RESULTS Surface roughness of GC were significantly lower than that of LU and VE (P<.05). The highest surface roughness was observed for dry grinding group, followed by airborne particle abraded group (P<.05). Comparing the materials within the same surface treatment method revealed that untreated surfaces generally showed lower SBS values. The values of untreated LU specimens showed significantly different SBS values compared to those of other surface treatment groups (P<.05). CONCLUSION SBS was affected by surface treatments. Thermocycling did not have any effect on the SBS of the materials except acid and silane applied GC specimens, which were subjected to thermocycling before packing of the composite resin. PMID:27555894

  16. Thermal Performance of Ablative/ Ceramic Composite

    Directory of Open Access Journals (Sweden)

    Adriana STEFAN

    2014-12-01

    Full Text Available A hybrid thermal protection system for atmospheric earth re-entry based on ablative materials on top of ceramic matrix composites is investigated for the protection of the metallic structure in oxidative and high temperature environment of the space vehicles. The paper focuses on the joints of ablative material (carbon fiber based CALCARB® or cork based NORCOAT TM and Ceramic Matrix Composite (CMC material (carbon fibers embedded in silicon carbide matrix, Cf/SiC, SICARBON TM or C/C-SiC using commercial high temperature inorganic adhesives. To study the thermal performance of the bonded materials the joints were tested under thermal shock at the QTS facility. For carrying out the test, the sample is mounted into a holder and transferred from outside the oven at room temperature, inside the oven at the set testing temperature (1100°C, at a heating rate that was determined during the calibration stage. The dwell time at the test temperature is up to 2 min at 1100ºC at an increasing rate of temperature up to ~ 9,5°C/s. Evaluating the atmospheric re-entry real conditions we found that the most suited cooling method is the natural cooling in air environment as the materials re-entering the Earth atmosphere are subjected to similar conditions. The average weigh loss was calculated for all the samples from one set, without differentiating the adhesive used as the weight loss is due to the ablative material consumption that is the same in all the samples and is up to 2%. The thermal shock test proves that, thermally, all joints behaved similarly, the two parts withstanding the test successfully and the assembly maintaining its integrity.

  17. Study on Microstructure of Alumina Based Rare Earth Ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Analysis techniques such as SEM, TEM and EDAX were used to investigate the microstructure of rare earth reinforced Al2O3/(W, Ti)C ceramic composite. Chemical and physical compatibility of the composite was analyzed and interfacial microstructure was studied in detail. It is found that both Al2O3 and (W, Ti)C phases are interlaced with each other to form the skeleton structure in the composite. A small amount of pores and glass phases are observed inside the material which will inevitably influence the physical and mechanical property of the composite. Thermal residual stresses resulted from thermal expansion mismatch can then lead to the emergence of dislocations and microcracks. Interfaces and boundaries of different types are found to exist inside the Al2O3/(W, Ti)C rare earth ceramic composite, which is concerned with the addition of rare earth element and the extent of solid solution of ceramic phases.

  18. Computer Modeling of Ceramic Boride Composites

    Science.gov (United States)

    2014-11-01

    AFRL-AFOSR-UK-TR-2015-0016 Computer Modeling of Ceramic Boride Composites Dr. Valeriy V. Kartuzov SCIENCE AND TECHNOLOGY...Research Laboratory Air Force Office of Scientific Research European Office of Aerospace Research and Development Unit 4515, APO AE 09421-4515...4. TITLE AND SUBTITLE Computer Modeling of Ceramic Boride Composites  5a. CONTRACT NUMBER STCU P-510 5b. GRANT NUMBER STCU 11-8003 5c

  19. Interfacial chemistry and structure in ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.H.; Saenz, N.T.; Schilling, C.H.

    1990-09-01

    The interfacial chemistry and structure of ceramic matrix composites (CMCs) play a major role in the properties of these materials. Fiber-matrix interfaces chemistries are vitally important in the fracture strength, fracture toughness, and fracture resistance of ceramic composites because they influence fiber loading and fiber pullout. Elevated-temperature properties are also linked to the interfacial characteristics through the chemical stability of the interface in corrosive environments and the creep/pullout behavior of the interface. Physical properties such as electrical and thermal conductivity are also dependent on the interface. Fiber-matrix interfaces containing a 1-{mu}m-thick multilayered interface with amorphous and graphitic C to a 1-nm-thick SiO{sub 2} layer can result from sintering operations for some composite systems. Fibers coated with C, BN, C/BC/BN, and Si are also used to produce controlled interface chemistries and structures. Growth interfaces within the matrix resulting from processing of CMCs can also be crucial to the behavior of these materials. Evaluation of the interfacial chemistry and structure of CMCs requires the use of a variety of analytical tools, including optical microscopy, scanning electron microscopy, Auger electron spectroscopy, and transmission electron microscopy coupled with energy dispersive x-ray analysis. A review of the interfacial chemistry and structure of SiC whisker- and fiber-reinforced Si{sub 3}N{sub 4} and SiC/SiC materials is presented. Where possible, correlations with fracture properties and high-temperature stability are made. 94 refs., 10 figs.

  20. Processing and characterization of an Al{sub 2}O{sub 3}/WC/TiC micro- nano-composite ceramic tool material

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Jun, E-mail: zhaojun@sdu.edu.cn [Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, School of Mechanical Engineering, Shandong University, 17923 Jingshi Road, Jinan 250061 (China); Yuan Xunliang [Seco Tools (Shanghai) Co. Ltd., Shanghai 200233 (China); Zhou Yonghui [Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, School of Mechanical Engineering, Shandong University, 17923 Jingshi Road, Jinan 250061 (China)

    2010-03-25

    An Al{sub 2}O{sub 3}-based composite ceramic tool material reinforced with WC microparticles and TiC nano-particles was fabricated by using hot-pressing technique with MgO and NiO as sintering aids. The experimental results showed that optimal mechanical properties were achieved for the composite with the addition of 24 vol.% TiC nano-particles and 16 vol.% WC microparticles, with the flexural strength, fracture toughness and Vicker's hardness being 842 MPa, 6.82 MPa m{sup 1/2} and 22.19 GPa, respectively. The microstructure and phase composition of the composites were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The fracture surface of the Al{sub 2}O{sub 3}/16 vol.%WC/24 vol.%TiC micro- nano-composite was characterized by a mix of intergranular and transgranular fracture as a result of the presence of both intergranular and intragranular secondary phase particles. It is believed that inhibition of matrix grain growth by intergranular secondary phase particles, sub-grain boundaries and dislocations pinning inside Al{sub 2}O{sub 3} grains induced by intragranular TiC nano-particles contribute to the strengthening of the composite. Meanwhile, the dislocations and microcracks inside the matrix grains can also increase the flaw-tolerance leading to high toughness of the composite. Additionally, some extrinsic processes including crack deflection, crack bridging and crack branching caused by the microstructural discontinuities and local stress state can absorb a great amount of fracture energy, which are beneficial for the toughening of the composite. However, future research will need to quantitatively understand the synergistic effect of TiC nano-particles and WC microparticles on strengthening and toughening mechanisms.

  1. An irradiation test of heat-resistant ceramic composite materials. Interim report on post-irradiation examinations of the first preliminary irradiation test: 97M-13A

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Shin-ichi; Takahashi, Tsuneo; Ishihara, Masahiro; Hayashi, Kimio; Sozawa, Shizuo; Saito, Takashi [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Suzuki, Yoshio [Nuclear Engineering, Co. Ltd., Osaka (Japan); Saito, Tamotsu; Sekino, Hajime [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    The Japan Atomic Energy Research Institute (JAERI) has been carrying out the research on radiation damage mechanism of heat-resistant ceramic composite materials, as one of the subjects of the innovative basic research on high temperature engineering using the High Temperature Engineering Test Reactor (HTTR). A series of preliminary irradiation tests is being made using the Japan Materials Testing Reactor (JMTR). The present report describes results of post-irradiation examinations (PIE) so far on specimens irradiated in the first capsule, designated 97M-13A, to fast neutron fluences of 1.2-1.8x10{sup 24} m{sup -2} (E>1 MeV) at temperatures of 573, 673 and 843 K. In the PIE, measurements were made on (1) dimensional changes, (2) thermal expansions, (3) X-ray parameters and (4) {gamma}-ray spectra. The results for the carbon/carbon and SiC/SiC composites were similar to those in existing literatures. The temperature monitor effect was observed both for SiC fiber- and particle-reinforced SiC composites as in the case of monolithic SiC. Namely, the curve of the coefficient of thermal expansion (CTE) of these specimens showed a rapid drop above a temperature around the irradiation temperature +100 K in the first ramp (ramp rate: 10 K/min), while in the second ramp the CTE curves were almost the same as those of un-irradiated SiC specimens. (author)

  2. Freeforming of Ceramics and Composites from Colloidal Slurries

    Energy Technology Data Exchange (ETDEWEB)

    CESARANO III,JOSEPH; DENHAM,HUGH B.; STUECKER,JOHN N.; BAER,THOMAS A.; GRIFFITH,MICHELLE L.

    1999-12-01

    This report is a summary of the work completed for an LDRD project. The objective of the project was to develop a solid freeform fabrication technique for ceramics and composites from fine particle slurries. The work was successful and resulted in the demonstration of a manufacturing technique called robocasting. Some ceramic components may pow be fabricated without the use of molds or tooling by dispensing colloidal suspensions through an orifice and stacking two-dimensional layers into three-dimensional shapes. Any conceivable two-dimensional pattern may be ''written'' layer by layer into a three-dimensional shape. Development of the robocasting technique required the materials expertise for fabrication and theological control of very highly concentrated fine particle slurries, and development of robotics for process control and optimization. Several ceramic materials have been manufactured and characterized. Development of techniques for robocasting multiple materials simultaneously have also been developed to build parts with unique structures or graded compositions.

  3. New ceramic materials; Nuevos materiales ceramicos

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, R.; Dominguez-Rodriguez, A.

    2010-07-01

    This article is to provide a new ceramic materials in which, with a control of their processing and thus their microstructural properties, you can get ceramic approaching ever closer to a metal, both in its structural behavior at low as at high temperatures. (Author) 30 refs.

  4. Parametric Study Of A Ceramic-Fiber/Metal-Matrix Composite

    Science.gov (United States)

    Murthy, P. L. N.; Hopkins, D. A.; Chamis, C. C.

    1992-01-01

    Report describes computer-model parametric study of effects of degradation of constituent materials upon mechanical properties of ceramic-fiber/metal-matrix composite material. Contributes to understanding of weakening effects of large changes in temperature and mechanical stresses in fabrication and use. Concerned mainly with influences of in situ fiber and matrix properties upon behavior of composite. Particular attention given to influence of in situ matrix strength and influence of interphase degradation.

  5. Formation and corrosion of a 410 SS/ceramic composite

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X.; Ebert, W. L.; Indacochea, J. E.

    2016-11-01

    This study evaluates the possible use of alloy/ceramic composite waste forms to immobilize metallic and oxide waste streams generated during the electrochemical reprocessing of spent reactor fuel in a single waste form. A representative composite material AOC410 was made to evaluate the microstructure and corrosion behavior at alloy/ceramic interfaces by reacting 410 stainless steel with Zr, Mo, and a mixture of lanthanide oxides. Essentially all of the Zr reacted with lanthanide oxides to form lanthanide zirconate, which combined with the remaining lanthanide oxides to form a porous ceramic network encapsulated by alloy as a composite puck. Excess alloy formed a metal bead on top of the composite. The alloys in the composite and bead were both mixture of martensite grains and ferrite grains with carbide precipitates. FeCrMo intermetallic phases also precipitated in the ferrite grains in the composite part. Ferrite surrounding carbides was sensitized and the least corrosion resistant in electrochemical corrosion tests conducted in an acidic brine electrolyte; ferrite neighboring martensite grains and intermetallics corroded galvanically. The lanthanide oxide domains dissolved chemically, but lanthanide zirconate domains did not dissolve. The presence of oxide phases did not affect corrosion of the neighboring alloy phases. These results suggest the longterm corrosion of a composite waste form can be evaluated by using separate material degradation models for the alloy and ceramic phases.

  6. Self-Assembling, Flexible, Pre-Ceramic Composite Preforms

    Science.gov (United States)

    Jaskowiak, Martha H.; Eckel, Andrew J.; Gorican, Daniel

    2009-01-01

    In this innovation, light weight, high temperature, compact aerospace structures with increased design options are made possible by using self-assembling, flexible, pre-ceramic composite materials. These materials are comprised of either ceramic or carbon fiber performs, which are infiltrated with polymer precursors that convert to ceramics upon thermal exposure. The preform architecture can vary from chopped fibers formed into blankets or felt, to continuous fibers formed into a variety of 2D or 3D weaves or braids. The matrix material can also vary considerably. For demonstration purposes, a 2D carbon weave was infiltrated with a SiC polymer precursor. The green or unfired material is fabricated into its final shape while it is still pliable. It is then folded or rolled into a much more compact shape, which will occupy a smaller space. With this approach, the part remains as one continuous piece, rather than being fabricated as multiple sections, which would require numerous seals for eventual component use. The infiltrated preform can then be deployed in-situ. The component can be assembled into its final shape by taking advantage of the elasticity of the material, which permits the structure to unfold and spring into its final form under its own stored energy. The pre-ceramic composites are converted to ceramics and rigidized immediately after deployment. The final ceramic composite yields a high-temperature, high-strength material suitable for a variety of aerospace structures. The flexibility of the material, combined with its high-temperature structural capacity after rigidization, leads to a less complex component design with an increased temperature range. The collapsibility of these structures allows for larger components to be designed and used, and also offers the potential for increased vehicle performance. For the case of collapsible nozzle extensions, a larger nozzle, and thus a larger nozzle exit plane, is possible because interference with

  7. Piezoelectric Polymer/Ceramic Composite

    Science.gov (United States)

    1989-05-02

    significant. The current in ?iEZEL samole was cbserved to reach steady state level in the region cf -i05 sec whereas in t-he prepared composites the tine talen ... technology is not a’ silable for prodccinc s;ch materials in tOe areas and thicknesses required for commecrcial applications in c:apacitolrs. Y~i5.h~4 ’~ x

  8. Hybrid Ceramic Matrix Fibrous Composites: an Overview

    Energy Technology Data Exchange (ETDEWEB)

    Naslain, R, E-mail: naslain@lcts.u-bordeaux1.fr [University of Bordeaux 3, Allee de La Boetie, 33600 Pessac (France)

    2011-10-29

    Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

  9. Overview: Damage resistance of graded ceramic restorative materials.

    Science.gov (United States)

    Zhang, Yu

    2012-08-01

    Improving mechanical response of materials is of great interest in a wide range of disciplines, including biomechanics, tribology, geology, optoelectronics, and nanotechnology. It has been long recognized that spatial gradients in surface composition and structure can improve the mechanical integrity of a material. This review surveys recent results of sliding-contact, flexural, and fatigue tests on graded ceramic materials from our laboratories and elsewhere. Although our findings are examined in the context of possible applications for next-generation, graded all-ceramic dental restorations, implications of our studies have broad impact on biomedical, civil, structural, and an array of other engineering applications.

  10. Fabrication of Ceramic Composites by Directed Metal Oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xi-ya; TAN Yue-hua

    2004-01-01

    To explain the growth mechanism of Al2O3/Al Lanxide composites, the dynamics of the directedoxidation of Al-Mg-Si alloys are analyzed. The experimental methods to produce Lanxide composites by directedoxidation of metal melts at high temperatures are presented. The effect of the processing factors on the microstruc-tures and properties of Al2O3/Al composites and enforced Al2O3/Al composites is also analyzed. Compared withsintering ceramic composites, the advantages of Lanxide process and Lanxide materials are as following: it is a nearnet shaped process; the process is very simple; the microstructures and properties of Lanxide materials can be adjust-ed; and this process can be used to infiltrate ceramic fiber or particle preforms .

  11. Ceramic Matrix Composites Performances Under High Gamma Radiation Doses

    Science.gov (United States)

    Cemmi, A.; Baccaro, S.; Fiore, S.; Gislon, P.; Serra, E.; Fassina, S.; Ferrari, E.; Ghisolfi, E.

    2014-06-01

    Ceramic matrix composites reinforced by continuous ceramic fibers (CMCs) represent a class of advanced materials developed for applications in automotive, aerospace, nuclear fusion reactors and in other specific systems for harsh environments. In the present work, the silicon carbide/silicon carbide (SiCf/SiC) composites, manufactured by Chemical Vapour Infiltration process at FN S.p.A. plant, have been evaluated in term of gamma radiation hardness at three different absorbed doses (up to around 3MGy). Samples behavior has been investigated before and after irradiation by means of mechanical tests (flexural strength) and by surface and structural analyses (X-ray diffraction, SEM, FTIR-ATR, EPR).

  12. Transport properties of ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Starr, T.L. [Georgia Inst. of Technology, Atlanta, GA (United States)

    1995-08-01

    This project involves experimental and modeling investigation of the transport properties of chemical vapor infiltration (CVI) preforms and densified composites, with particular emphasis on gas permeability and mass diffusivity. The results of this work will be useful both for on-going CVI process development and for evaluation and optimization of composite materials for fossil energy applications. With preforms made with 500 filaments/tow Nicalon at 40 vol% fiber loading, permeability values are similar for square-weave cloth layup and 3-D weave at low density. At greater densification the 3-D weave permeability is lower and approaches zero with significantly more closed porosity than the cloth layup. For filament wound preforms we were unable to make reliable measurements with the available materials. A model for gas transport in these materials utilizes percolation theory concepts. The ultimate achievable density is related to the closing of a continuous gas path through the preform. As the density approaches this limit the gas permeability and diffusivity vanish exponentially. The value of this limit is controlled primarily by the preform fiber architecture. The observed difference between the cloth layup and 3-D weave materials is due to the larger pores at tow crossing points found in the 3-D weave.

  13. Transport properties of ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Starr, T.L.; Hablutzel, N. [Georgia Institute of Technology, Atlanta, GA (United States)

    1996-08-01

    Instrumentation and procedures have been completed for measurement of gas permeability and mass diffusivity of fiber preforms and porous materials. Results are reported for composites reinforced with Nicalon fiber in cloth lay-up and 3-D weave and with Nextel fiber in multi-layer braid. Measured permeability values range from near 100 to less than 0.1 darcies. Mass diffusivity is reported as a structure factor relating the diffusion through the porous material to that in free space. This measure is independent of the diffusing species and depends only on the pore structure of the material. Measurements are compared to predictions of a node-bond model for gas transport. Model parameters adjusted to match measured transport properties relate to physical microstructure features of the different architectures. Combination of this transport model with the CVI process model offers a predictive method to evaluate the densification behavior of various fiber preforms.

  14. Key Issues for Aerospace Applications of Ceramic Matrix Composites

    Science.gov (United States)

    Clinton, R. G., Jr.; Levine, S. R.

    1998-01-01

    Ceramic matrix composites (CMC) offer significant advantages for future aerospace applications including turbine engine and liquid rocket engine components, thermal protection systems, and "hot structures". Key characteristics which establish ceramic matrix composites as attractive and often enabling choices are strength retention at high temperatures and reduced weight relative to currently used metallics. However, due to the immaturity of this class of materials which is further compounded by the lack of experience with CMC's in the aerospace industry, there are significant challenges involved in the development and implementation of ceramic matrix composites into aerospace systems. Some of the more critical challenges are attachment and load transfer methodologies; manufacturing techniques, particularly scale up to large and thick section components; operational environment resistance; damage tolerance; durability; repair techniques; reproducibility; database availability; and the lack of validated design and analysis tools. The presentation will examine the technical issues confronting the application of ceramic matrix composites to aerospace systems and identify the key material systems having potential for substantial payoff relative to the primary requirements of light weight and reduced cost for future systems. Current programs and future research opportunities will be described in the presentation which will focus on materials and processes issues.

  15. Support Services for Ceramic Fiber-Ceramic Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.P.

    2000-06-06

    Structural and functional materials used in solid- and liquid-fueled energy systems are subject to gas- and condensed-phase corrosion and erosion by entrained particles. For a given material, its temperature and the composition of the corrodents determine the corrosion rates, while gas flow conditions and particle aerodynamic diameters determine erosion rates. Because there are several mechanisms by which corrodents deposit on a surface, the corrodent composition depends not only on the composition of the fuel, but also on the temperature of the material and the size range of the particles being deposited. In general, it is difficult to simulate under controlled laboratory conditions all of the possible corrosion and erosion mechanisms to which a material may be exposed in an energy system. Therefore, with funding from the Advanced Research Materials Program, the University of North Dakota Energy & Environmental Research Center (EERC) is coordinating with NCC Engineering and the National Energy Technology Laboratory (NETL) to provide researchers with no-cost opportunities to expose materials in pilot-scale systems to conditions of corrosion and erosion similar to those occurring in commercial power systems. The EERC has two pilot-scale solid-fuel systems available for exposure of materials coupons. The slagging furnace system (SFS) was built under the DOE Combustion 2000 Program as a testing facility for advanced heat exchanger subsystems. It is a 2.5-MMBtu/hr (2.6 x 10{sup 6} kJ/hr) solid-fuel combustion system with exit temperatures of 2700 to 2900 F to ensure that the ash in the main combustor is molten and flowing. Sample coupons may be exposed in the system either within the slagging zone or near the convective air heater at 1800 F (980 C). In addition, a pilot-scale entrained-bed gasifier system known as the transport reactor development unit (TRDU) is available. Also operating at approximately 2.5 MMBtu/hr (2.6 x 10{sup 6} kJ/hr), it is a pressurized unit

  16. Silicone Resin Applications for Ceramic Precursors and Composites

    Directory of Open Access Journals (Sweden)

    Masaki Narisawa

    2010-06-01

    Full Text Available This article reviews the applications of silicone resins as ceramic precursors. The historical background of silicone synthesis chemistry is introduced to explain the production costs and supply availability of various silicones. Thermal degradation processes of silicones are classified in terms of the main chain structure and cyclic oligomer expulsion process, which determine the resulting ceramic yield and the chemical composition. The high temperature decomposition of Si-O-C beyond 1,400 °C in an inert atmosphere and formation of a protective silica layer on material surfaces beyond 1,200 °C in an oxidative atmosphere are discussed from the viewpoints of the wide chemical composition of the Si-O-C materials. Applications of the resins for binding agents, as starting materials for porous ceramics, matrix sources with impregnation, fiber spinning and ceramic adhesions are introduced. The recent development of the process of filler or cross-linking agent additions to resin compounds is also introduced. Such resin compounds are useful for obtaining thick coatings, MEMS parts and bulk ceramics, which are difficult to obtain by pyrolysis of simple organometallic precursors without additives.

  17. Multilayer Electroactive Polymer Composite Material

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2011-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  18. Dynamic properties of ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Grady, D.E. [Sandia National Labs., Albuquerque, NM (United States). Experimental Impact Physics Dept.

    1995-02-01

    The present study offers new data and analysis on the transient shock strength and equation-of-state properties of ceramics. Various dynamic data on nine high strength ceramics are provided with wave profile measurements, through velocity interferometry techniques, the principal observable. Compressive failure in the shock wave front, with emphasis on brittle versus ductile mechanisms of deformation, is examined in some detail. Extensive spall strength data are provided and related to the theoretical spall strength, and to energy-based theories of the spall process. Failure waves, as a mechanism of deformation in the transient shock process, are examined. Strength and equation-of-state analysis of shock data on silicon carbide, boron carbide, tungsten carbide, silicon dioxide and aluminum nitride is presented with particular emphasis on phase transition properties for the latter two. Wave profile measurements on selected ceramics are investigated for evidence of rate sensitive elastic precursor decay in the shock front failure process.

  19. Material Constitutive Models for Creep and Rupture of SiC/SiC Ceramic-Matrix Composites (CMCs) Under Multiaxial Loading

    Science.gov (United States)

    Grujicic, Mica; Galgalikar, R.; Snipes, J. S.; Ramaswami, S.

    2016-05-01

    Material constitutive models for creep deformation and creep rupture of the SiC/SiC ceramic-matrix composites (CMCs) under general three-dimensional stress states have been developed and parameterized using one set of available experimental data for the effect of stress magnitude and temperature on the time-dependent creep deformation and rupture. To validate the models developed, another set of available experimental data was utilized for each model. The models were subsequently implemented in a user-material subroutine and coupled with a commercial finite element package in order to enable computational analysis of the performance and durability of CMC components used in high-temperature high-stress applications, such as those encountered in gas-turbine engines. In the last portion of the work, the problem of creep-controlled contact of a gas-turbine engine blade with the shroud is investigated computationally. It is assumed that the blade is made of the SiC/SiC CMC, and that the creep behavior of this material can be accounted for using the material constitutive models developed in the present work. The results clearly show that the blade-tip/shroud clearance decreases and ultimately becomes zero (the condition which must be avoided) as a function of time. In addition, the analysis revealed that if the blade is trimmed at its tip to enable additional creep deformation before blade-tip/shroud contact, creep-rupture conditions can develop in the region of the blade adjacent to its attachment to the high-rotational-speed hub.

  20. Robocasting of Ceramics and Composites Using Fine Particle Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    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

  1. Effects of superfine refractory carbide additives on microstructure and mechanical properties of TiB{sub 2}–TiC+Al{sub 2}O{sub 3} composite ceramic cutting tool materials

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Bin, E-mail: zou20011110@163.com [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Shandong University, Ministry of Education (China); Ji, Wenbin; Huang, Chuanzhen; Wang, Jun [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Shandong University, Ministry of Education (China); Li, Shasha [Shandong Special Equipment Inspection Institute, Jinan 250013 (China); Xu, Kaitao [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Shandong University, Ministry of Education (China)

    2014-02-05

    Highlights: • The superfine carbides determined the mechanical properties of composites. • Superfine HfC or TaC caused some oxide impurities in composites. • Superfine VC or NbC refined and homogenized the microstructure. • Failure of composites containing HfC or TaC was produced by larger grains. • Composite containing VC exhibited more bridging and transcrystalline failure. -- Abstract: A study to increase the mechanical properties of TiB{sub 2}–TiC+Al{sub 2}O{sub 3} composite ceramic cutting tool material by using superfine refractory carbide additives is presented. Four superfine refractory carbides are considered to investigate their effects on the phase composition, element distribution, grain size, fracture surface, crack propagation of the metal ceramic. The physicochemical properties of superfine carbides, such as chemical activities and atom radius, were found to have the significant effects on the microstructure and mechanical properties of the metal ceramic. Hafnium carbide (HfC) and Tantalum carbide (TaC) reduced the mechanical properties of the metal ceramic because of their poor solubility with the Ni binder phase and the formation of oxides. The mechanical properties of the metal ceramic were increased by the addition of superfine niobium carbide (NbC) and vanadium carbide (VC), and their optimum values were a flexural strength of 1100 ± 62 MPa, fracture toughness of 8.5 ± 0.8 MPa.m1/2 and hardness of 21.53 ± 0.36 GPa, respectively, when 3.2 wt% superfine VC was used.

  2. Formation and corrosion of a 410 SS/ceramic composite

    Science.gov (United States)

    Chen, X.; Ebert, W. L.; Indacochea, J. E.

    2016-11-01

    This study addressed the possible use of alloy/ceramic composite waste forms to immobilize metallic and oxide waste streams generated during the electrochemical reprocessing of spent reactor fuel using a single waste form. A representative composite material was made to evaluate the microstructure and corrosion behavior at alloy/ceramic interfaces by reacting 410 stainless steel with Zr, Mo, and a mixture of lanthanide oxides. Essentially all of the available Zr reacted with lanthanide oxides to generate lanthanide zirconates, which combined with the unreacted lanthanide oxides to form a porous ceramic network that filled with alloy to produce a composite puck. Alloy present in excess of the pore volume of the ceramic generated a metal bead on top of the puck. The alloys in the composite and forming the bead were both mixtures of martensite grains and ferrite grains bearing carbide precipitates; FeCrMo intermetallic phases also precipitated at ferrite grain boundaries within the composite puck. Micrometer-thick regions of ferrite surrounding the carbides were sensitized and corroded preferentially in electrochemical tests. The lanthanide oxides dissolved chemically, but the lanthanide zirconates did not dissolve and are suitable host phases. The presence of oxide phases did not affect corrosion of the neighboring alloy phases.

  3. Ceramic Wetlaid Nonwoven and Its Composite

    Institute of Scientific and Technical Information of China (English)

    CHENG Long-di; HUANG Xiu-bao; YU Xiu-ye

    2002-01-01

    The paper deals with the properties of wetlaid nonwovens and their composites in two different blended fibers (polyester and aromatic fiber pulp) and ceramic fiber pulp mainly. The conclusion is that high blending ratio of blended fiber will lead to the worse properties of the products.

  4. Oxidation-resistant interfacial coatings for continuous fiber ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.; Besmann, T.M.; Bleier, A. [Oak Ridge National Lab., TN (United States); Shanmugham, S.; Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-08-01

    Continuous fiber ceramic composites mechanical behavior are influenced by the bonding characteristics between the fiber and the matrix. Finite modeling studies suggest that a low-modulus interfacial coating material will be effective in reducing the residual thermal stresses that are generated upon cooling from processing temperatures. Nicalon{trademark}/SiC composites with carbon, alumina and mullite interfacial coatings were fabricated with the SiC matrix deposited using a forced-flow, thermal gradient chemical vapor infiltration process. Composites with mullite interfacial coatings exhibited considerable fiber pull-out even after oxidation and have potential as a composite system.

  5. Fracture characteristics of refractory composites containing metakaolin and ceramic fibers

    Directory of Open Access Journals (Sweden)

    Ondřej Holčapek

    2015-03-01

    Full Text Available The aim of present article is to describe influence of composition of refractory composites on its response to gradual thermal loading. Attention was focused on the impact of ceramic fibers and application of metakaolin as an aluminous cement supplementary material. Studied aluminate binder system in combination with natural basalt fine aggregates ensures sufficient resistance to high-temperature exposure. Influence of composition changes was evaluated by the results of physical and mechanical testing—compressive and flexural strength, bulk density, and fracture energy were determined on the different levels of temperature loading. Application of ceramic fibers brought expected linear increase of ductility in studied composites. Metakaolin replacement showed the optimal dose to be just about 20% of aluminous cement weight.

  6. Experimental Investigation on Active Cooling for Ceramic Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    PENG Li-na; HE Guo-qiang; LIU Pei-jin

    2009-01-01

    Compared with conventional materials, the active cooling ceramic matrix composite used in ramjet or scramjet makes their structures lighter in mass and better in performance. In this paper, an active and a passive cooling refractory composite specimens are designed and tested with an experimental facility composed of multilayer smale scale cooling penel which consists of a water cooling system and a ceramic matrix composite specimen, and a gas generator used for providing lower and higher transfer rate gases to simulate the temperatures in combustion chamber of ramjst. The active cooling specimen can continuously suffer high surface temperature of 2 000K for 30s and that of 3 000 K for 9.3 s, respectively. The experiment results show that the active cooling composite structure is available for high-temperature condition in ramjet.

  7. Derivation, parameterization and validation of a creep deformation/rupture material constitutive model for SiC/SiC ceramic-matrix composites (CMCs

    Directory of Open Access Journals (Sweden)

    Mica Grujicic

    2016-05-01

    Full Text Available The present work deals with the development of material constitutive models for creep-deformation and creep-rupture of SiC/SiC ceramic-matrix composites (CMCs under general three-dimensional stress states. The models derived are aimed for use in finite element analyses of the performance, durability and reliability of CMC turbine blades used in gas-turbine engines. Towards that end, one set of available experimental data pertaining to the effect of stress magnitude and temperature on the time-dependent creep deformation and rupture, available in the open literature, is used to derive and parameterize material constitutive models for creep-deformation and creep-rupture. The two models derived are validated by using additional experimental data, also available in the open literature. To enable the use of the newly-developed CMC creep-deformation and creep-rupture models within a structural finite-element framework, the models are implemented in a user-material subroutine which can be readily linked with a finite-element program/solver. In this way, the performance and reliability of CMC components used in high-temperature high-stress applications, such as those encountered in gas-turbine engines can be investigated computationally. Results of a preliminary finite-element analysis concerning the creep-deformation-induced contact between a gas-turbine engine blade and the shroud are presented and briefly discussed in the last portion of the paper. In this analysis, it is assumed that: (a the blade is made of the SiC/SiC CMC; and (b the creep-deformation behavior of the SiC/SiC CMC can be represented by the creep-deformation model developed in the present work.

  8. Composite treatment of ceramic tile armor

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, James G. R. [Oak Ridge, TN; Frame, Barbara J [Oak Ridge, TN

    2010-12-14

    An improved ceramic tile armor has a core of boron nitride and a polymer matrix composite (PMC) facing of carbon fibers fused directly to the impact face of the tile. A polyethylene fiber composite backing and spall cover are preferred. The carbon fiber layers are cured directly onto the tile, not adhered using a separate adhesive so that they are integral with the tile, not a separate layer.

  9. Composite treatment of ceramic tile armor

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, James G. R. [Oak Ridge, TN; Frame, Barbara J [Oak Ridge, TN

    2012-01-02

    An improved ceramic tile armor has a core of boron nitride and a polymer matrix composite (PMC) facing of carbon fibers fused directly to the impact face of the tile. A polyethylene fiber composite backing and spall cover are preferred. The carbon fiber layers are cured directly onto the tile, not adhered using a separate adhesive so that they are integral with the tile, not a separate layer.

  10. Glass-ceramics as building materials

    Directory of Open Access Journals (Sweden)

    Rincón, J. María

    1996-06-01

    Full Text Available Glass-ceramics are materials composed as any ceramic material by several crystalline phases embedded in an amorphous or vitreous matrix, but their manufacture process implies the controlled devitrification or nucleation and growth of phases from an original glass. The original shape of the original glass molded by conventional methods is carried out by using pressing and sintering followed by crystallization steps. By both processing routes are obtained transparent and/or opaque materials, with or without colours, which after adequate control and design of composition and microstructure have numerous domestic and architectonic applications. They can be used as pavements or wall coatings and in various decorative elements. In fact, their use is very extensive in east-European, American and Asian (Japan countries in constructions for covering large surfaces. The greater advantage of the glass-ceramic process is that due to the own process of vitrification allows the incorporation in their structure of a wide range of compositions from mining and industrial residues, such as red muds, ashes, fangos, scraps... which they can in this way not only be inertizated, but furthermore it be converted without risk for the environment into products useful in construction applications, offering to the architect and to the decorator a new range of "eco-materials" with multiple complementary possibilities of the already existing architectural materials in the market.

    Los productos o materiales vitrocerámicos se componen, como cualquier material de tipo cerámico, de una o varias fases cristalinas embebidas en una matriz amorfa o vítrea, pero cuyo proceso de fabricación implica la desvitrificación o nucleación y cristalización controlada de un vidrio original o de partida. En el proceso de obtención de estos materiales se puede conservar la forma original conferida al vidrio de partida por los métodos convencionales de moldeado de vidrios

  11. Tension-Compression Fatigue of an Oxide/Oxide Ceramic Matrix Composite at Elevated Temperature in Air and Steam Environments

    Science.gov (United States)

    2015-03-26

    than several other advanced aerospace materials [15]. It is these qualities that make ceramics candidate materials for advanced aerospace ...TENSION-COMPRESSION FATIGUE OF AN OXIDE/OXIDE CERAMIC MATRIX COMPOSITE AT ELEVATED TEMPERATURE IN...is not subject to copyright protection in the United States. AFIT-ENY-MS-15-M-222 TENSION-COMPRESSION FATIGUE OF AN OXIDE/OXIDE CERAMIC MATRIX

  12. The teaching of all-ceramic restorations in North American dental schools: materials and techniques employed.

    Science.gov (United States)

    Frazier, K B; Mjör, I A

    1997-01-01

    North American dental schools were surveyed to determine the types of clinical experiences and the extent of material use that predoctoral students encounter with restorative procedures that employ all-ceramic materials. The results were based on an overall response rate of 80% from the 64 surveyed schools. The majority (96%) of the 51 schools responding to the survey did offer an opportunity to become experienced with all-ceramic restorations. The selection of bases and liners for all-ceramic restorations included dentin adhesive agents, glass ionomer materials, and calcium hydroxide products, by a ratio of 5:4:1, respectively. The most commonly used impression material types were addition silicone and polyether. One or both of these materials were used by every school. Dicor glass ceramic and alumina core ceramic were the most commonly used materials by the responding schools for veneers, onlays, and crowns. Dicor glass ceramic and CAD/CAM ceramic were most commonly used for inlays. Crowns were made of more different all-ceramic material types than the other restoration classes. Fabrication of all-ceramic restorations was primarily by commercial laboratories and school technicians. Students have hands-on experience in the fabrication of all-ceramic restorations in 6% of the responding schools. Luting agents for all-ceramic restorations include dual-cured resin, in 96% of the responding schools, light-cured resin, 43%, and glass ionomer cement, 33%. Zinc phosphate, chemical-cured composite, and polycarboxylate were used by less than one fourth of the respondents. Only resin-based composite materials were used to lute ceramic veneers. Rubber dam was applied primarily during luting procedures involving all-ceramic inlays and onlays. Crowns and veneers were isolated by this method in less than 30% of the responding schools. Finishing procedures with all-ceramic restorations were accomplished with three or more instruments by 89% of the schools.

  13. Integration Science and Technology of Silicon-Based Ceramics and Composites:Technical Challenges and Opportunities

    Science.gov (United States)

    Singh, M.

    2013-01-01

    Ceramic integration technologies enable hierarchical design and manufacturing of intricate ceramic and composite parts 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 for high temperature applications, detailed understanding of various thermochemical and thermomechanical factors is critical. Different technical approaches are required for the integration of ceramic to ceramic and ceramic to metal systems. Active metal brazing, in particular, is a simple and cost-effective method to integrate ceramic to metallic components. Active braze alloys usually contain a reactive filler metal (e.g., Ti, Cr, V, Hf etc) that promotes wettability and spreading by inducing chemical reactions with the ceramics and composites. In this presentation, various examples of brazing of silicon nitride to themselves and to metallic systems are presented. Other examples of joining of ceramic composites (C/SiC and SiC/SiC) using ceramic interlayers and the resulting microstructures are also presented. Thermomechanical characterization of joints is presented for both types of systems. In addition, 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 integrated system testing under simulated application conditions will also be presented.

  14. Numerical Homogenization of Protective Ceramic Composite Layers using the Hybrid Finite-Discrete Element Methods

    Directory of Open Access Journals (Sweden)

    Zainorizuan Mohd Jaini

    2013-12-01

    Full Text Available Innovative technologies have resulted in more effective ceramic composite as high rate loading-resistance and protective layer. The ceramic composite layer consists of ceramic frontal plate that bonded by softer-strong reinforced polymer network, consequently gains the heterogeneous condition. These materials serve specific purposes of defeating high rate loading and maintaining the structural integrity of the layer. Further due to the lack of a constituent material and tedious problem in heterogonous material modelling, a numerical homogenization is employed to analyse the isotropic material properties of ceramic composite layer in homogenous manner. The objective of this study is to derive a constitutive law of the ceramic composite using the multi-scale analysis. Two-dimensional symmetric macrostructure of the ceramic composite was numerically modelled using the hybrid finite-discrete element method to investigate the effective material properties and strength profile. The macrostructure was modelled as brittle material with nonlinear material properties. The finite element method is incorporated with a Rankine-Rotating Crack approach and discrete element to model the fracture onset. The prescribed uniaxial and biaxial loadings were imposed along the free boundaries to create different deformations. Due to crack initiation on the macrostructure, the averaged stresses were calculated to plot the stress-strain curves and the effective yield stress surface. From the multi-scale analysis, the rate-dependency of Mohr-Coulomb constitutive law was derived for the ceramic composite layer.

  15. Synthesis of Hafnium-Based Ceramic Materials for Ultra-High Temperature Aerospace Applications

    Science.gov (United States)

    Johnson, Sylvia; Feldman, Jay

    2004-01-01

    This project involved the synthesis of hafnium (Hf)-based ceramic powders and Hf-based precursor solutions that were suitable for preparation of Hf-based ceramics. The Hf-based ceramic materials of interest in this project were hafnium carbide (with nominal composition HE) and hafnium dioxide (HfO2). The materials were prepared at Georgia Institute of Technology and then supplied to research collaborators Dr. Sylvia Johnson and Dr. Jay Feldman) at NASA Ames Research Center.

  16. XRD applied to the determination of pigments and composition of lithic materials and ceramics from archaeological pre-hispanic sites of the Rio de la Plata

    Energy Technology Data Exchange (ETDEWEB)

    Beovide, Laura [Department of Archeology, National Museum of Anthropology, Montevideo, (Uruguay); Pardo, Helena; Faccio, Ricardo; Mombru, Alvaro [Centro NanoMat, Polo Tecnologico de Pando, Facultad de Quimica, Universidad de la Republica, Pando, Canelones (Uruguay); Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Facultad de Quimica, Universidad de la Republica, Gral, Montevideo (Uruguay); Piston, Mariela, E-mail: mpiston@fq.edu.u [Analytical Chemistry, Estrella Campos Department, Facultad de Quimica, Universidad de la Republica, Montevideo (Uruguay)

    2011-07-01

    Full text: The earliest records of human occupation on the lower basin of Santa Lucia River are dated ca. 4800 {sup 14}C years BP, in the area of one of the major tributaries of the Rio de la Plata on the Uruguayan coast. These societies were basically hunters and gatherers until ca. 3000 {sup 14}C years BP when they incorporated the horticulture. In this multidisciplinary work, two cases of application of XRD analysis of archaeological materials are presented to provide new perspectives in solving various problems related to the technological organization of these societies. In the first case, ceramics and pigments from an archaeological context prior to the hispanic-indian contact were analyzed. The X-ray powder diffraction patterns were obtained using a RIGAKU, Ultima IV with CBO monochromator, CuK{sub {alpha}} radiation was at 40 kV and 20 mA tube power at 0.02 deg/seg, operating in the range from 2{theta}=5.00 to 60.00 deg. According the comparison between the experimental recorded X-ray diffraction pattern to those stored in a X-ray powder diffraction database reveals that the piece of pottery is mainly constitute of quartz (SiO{sub 2}) and hematite (Fe{sub 2}O{sub 3}) while the mineral sample is probably composed mainly of quartz (SiO{sub 2}) and goethite (FeO{sub 3}.H{sub 2}O). The results allow a first approximation to know the inorganic pigments that were part of the decoration of the pottery and pigments used in the archaeological context. In the second case an amphibolite instrument from ca. 2700 {sup 14}C years BP related to a shell midden was analyzed and compared with amphibolites located 15 km of the archaeological site to assess if they were the raw materials for these instruments. Compositional XRD mineralogical analysis shows that the both samples seem to have similar mineral composition, which is mainly quartz (SiO{sub 2}) and a mixed sodium magnesium and calcium silicate (NaCa{sub 2}(Mg{sub 4}Ti)Si{sub 6}Al{sub 2}O{sub 23}(OH){sub 2}). This

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

    Science.gov (United States)

    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.

  18. Metal-ceramic materials. Study and prediction of effective mechanical properties

    Science.gov (United States)

    Karakulov, Valerii V.; Smolin, Igor Yu.

    2016-08-01

    Mechanical behavior of stochastic metal-ceramic composite materials was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites, whose structure consists of a metal matrix and randomly distributed ceramic inclusions, was numerically simulated. The results of the numerical simulation were used for evaluation of the effective elastic and strength properties of metal-ceramic materials with different parameters of the structure. The values of the effective mechanical properties of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure parameters of composites was determined.

  19. Composites (CFCCs) for low cost energy and cleaner environment. Continuous fiber ceramic composites program

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    For many industrial applications, materials are desired which combine light weight, high temperature strength, and stability in corrosive environments. Among competing materials, ceramics are noteworthy candidates for such applications. The use of ceramics is often constrained, however, by brittleness; i.e., low toughness. Ceramic composites are being developed to overcome this limitation. With recent advances in ceramic fiber technology, it is possible to design a composite material based on continuous ceramic fibers embedded in a ceramic matrix. The use of ceramic composites in industrial applications will result in reduced fuel consumption, but will also prevent airborne pollution (principally NO, SO{sub x}, CO{sub 2}, and particulates), and economically benefit the end user through energy and environmental savings and increased competitiveness. Industry will also benefit through increased productivity and consumers will benefit through lower energy and environmental costs and a cleaner environment. The development and use of CFCCs could become an important factor in the international competitiveness of U.S. industry. CFCCs will be a critical enabling material in the design and engineering of advanced components, systems, and processes. If CFCC technology is developed outside the United States, domestic users of these materials may be forced to rely on foreign suppliers of the products fabricated from CFCCs, as well as the materials themselves. Foreign countries, including Japan and France, have embarked on government-supported CFCC development efforts. With the market for CFCC products expected to be a $10 billion dollar market by 2010, CFCC development will be important for the competitiveness of U.S. industry and for retaining and creating jobs for U.S. citizens. This document summarizes the potential energy, environmental, and economic benefits that CFCCs will have for the U.S. economy and particularly for the industrial sector.

  20. Broadband dielectric response of AlN ceramic composites

    Directory of Open Access Journals (Sweden)

    Iryna V. Brodnikovska

    2014-03-01

    Full Text Available Aluminium nitride (AlN is considered as a substrate material for microelectronic applications. AlN ceramic composites with different amount of TiO2 (up to 4 vol.% were obtained using hot pressing at different sintering temperature from 1700 to 1900 °C. It was shown that milling of the raw AlN powder has strongly influence on sintering and improves densification. Broadband dielectric spectroscopy was used as a nondestructive method for monitoring of the ceramic microstructures. TiO2 additive affects the key properties of AlN ceramics. Thus, porosity of 0.1 %, dielectric permeability of σ = 9.7 and dielectric loss tangent of tanδ = 1.3·10-3 can be achieved if up to 2 vol.% TiO2 is added.

  1. MECHANO-CHEMICAL EFFECTS ON SYNTHESIS OF CERAMIC MATERIALS AND ITS COMPOSITIONS%陶瓷及其复合材料合成的机械力化学效应

    Institute of Scientific and Technical Information of China (English)

    王燕民; 潘志东

    2005-01-01

    介绍了陶瓷及其复合材料(如:氧化物陶瓷、生物陶瓷、电子陶瓷、微波绝缘复合陶瓷、电池材料和sialon陶瓷复合材料)合成的机械力化学效应研究的进展.软机械力化学合成方法的生产成本低,将该方法用于工业化生产各种陶瓷材料具有相当大的应用前景.通过选择合适的原料和研磨条件,机械力化学合成的方法可用于制备很多高性能无机材料.用机械力化学合成的方法可加速并简化合成反应,减少能量和原材料的消耗,即经济又环保.同时,机械力化学合成的方法可以通过非常规的途径使纳米结构陶瓷材料晶化反应快速进行.针对此研究领域将来的发展方向提出了建议.%This paper reviews recent developments on mechano-chemical synthesis of various ceramic materials and compositions (such as oxide ceramics, biomaterial ceramics, electronic and electric intermetallics, microwave dielectric composite, battery compounds, and sialon ceramic compositions). The method of soft mechano-chemical synthesis has a considerable potential for low cost, large scale production of various ceramic materials. The technique can be extended to the synthesis of a very wide range of various powders of advanced inorganic materials by the suitable selection of starting materials and milling conditions. The method accelerates and simplifies the process of the synthesis, decreases the energy expenses and the cost of the materials,thus being more economically efficient and ecologically clean. The mechano-chemical procedure permits an unique preparativeflexibility allowing for rapid solid-phase crystallisation of nano-structured ceramic materials. Further studies in this aspect are also proposed.

  2. Cupric Hexacyanoferrate Nanoparticle Modified Carbon Ceramic Composite Electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG,Peng(王鹏); ZHU,Guo-Yi(朱果逸)

    2002-01-01

    Graphite powder-supported cupric hexacyanoferrate (CuHCF)nanoparticles were dispersed into methyltrimethoxysilane-based gels to produce a conducting carbon ceramic composite, which was used as electrode material to fabricate surface-renewable CuHCF-modified electrodes. Electrochemical behavior of the CuHCF-modified carbon ceramic composite electrodes was characterized using cyclic and square-wave voitammetry.Cyclic voltammograms at various scan rates indicated that peak currents were surface-confined at low scan rates. In the presence of glutathione, a clear electrocatalytic response was observed at the CuHCF-modified composite electrodes. In addition, the electrodes exhibited a distinct advantage of reproducible surface-renewal by simple mechanical polishing on emery paper, as well as ease of preparation, and good chemical and mechanical stability in a flowing stream.

  3. Cupric Hexacyanoferrate Nanoparticle Modified Carbon Ceramic Composite Electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG,Peng; ZHU,Guo-Yi

    2002-01-01

    Graphite powder-supported cupric hexacyanoferrate(CuHCF) nanoparticles were dispersed into methyltrimethoxysilane-based gels to produce a conducting carbon ceramic composite,which was used as electrode materials to fabricate surface-renewable CuHCF-modified electrodes.Electrochemical behavior of the CuHCF-modified carbon ceramic composite electrodes was characterized using cyclic and square-wave voltammetry. Cyclinc voltammograms at various scan rates indicated that peak currents were suface-confined at low scan rates.In the presence of glutathione,a clear electrocatalytic response was observed at the CuHCF-modified composite electrodes.In addition,the electrodes exhibited a distinct advantage of reproducible surface-renewal by simple mechanical polishing on emery paper,as well as ease of preparation,and good chemical and mechanical stability in a flowing stream.

  4. Smart Energy Materials of PZT Ceramics

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Okayasu

    2017-03-01

    Full Text Available To better understand the material properties of lead zirconate titanate (PZT ceramics, the domain-switching characteristics and electric power generation characteristics have been investigated during loading and unloading by using various experimental techniques. Furthermore, the influence of oscillation condition on the electrical power generation properties of lead zirconate titanate (PZT piezoelectric ceramics has been investigated. It is found that the power generation is directly attributed to the applied load and wave mode. The voltage rises instantly to the maximum level under square-wave mode, although the voltage increases gradually under triangular-wave mode. After this initial increase, there is a rapid fall to zero, followed by generation of increasingly negative voltage as the applied load is removed for all wave modes. Variation of the electric voltage is reflected by the cyclic loading at higher loading frequencies. On the basis of the obtained experimental results for the wave modes, the electrical power generation characteristics of PZT ceramics are proposed, and the voltages generated during loading and unloading are accurately estimated. The electric generation value is decrease with increasing the cyclic number due to the material failure, e.g., domain switching and crack. The influence of domain switching on the mechanical properties PZT piezoelectric ceramics is clarified, and 90 degree domain switching occurs after the load is applied to the PZT ceramic directly. Note that, in this paper, our experimental results obtained in our previous works were introduced

  5. Current Issues with Environmental Barrier Coatings for Ceramics and Ceramic Composites

    Science.gov (United States)

    Lee, Kang N.

    2004-01-01

    The environmental barrier coating (EBC) for SiC/SiC ceramic matrix composites and Si3N4 ceramics is an emerging field as the application of silicon-based ceramics in the gas turbine engine hot section is on the horizon, both for aero and industrial gas turbines. EBC is an enabling technology for silicon-based ceramics because these materials without an EBC cannot be used in combustion environments due to rapid surface recession. Significant progress in EBC development has been made during the last decade through various government-sponsored programs. Current EBCs are based on silicon, mullite (3Al2O3-2SiO2) and BSAS (barium strontium aluminum silicate with celsian structure). Volatility of BSAS, BSAS-silica chemical reaction, and low melting point of silicon limit temperature capability of current EBCs to about 1350 C for long-term applications. There is a need for higher temperature EBCs as the temperature capability of silicon-based ceramics continue to increase. Therefore, research is underway to develop EBCs with improved temperature capability compared to current EBCs. The current status and issues with the advanced EBC development efforts will be discussed.

  6. Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications

    OpenAIRE

    Dassios, Konstantinos G.; Evangelos Z. Kordatos; Dimitrios G. Aggelis; Matikas, Theodore E.

    2013-01-01

    Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specificall...

  7. Additive Manufacturing of SiC Based Ceramics and Ceramic Matrix Composites

    Science.gov (United States)

    Halbig, Michael Charles; Singh, Mrityunjay

    2015-01-01

    Silicon carbide (SiC) ceramics and SiC fiber reinforcedSiC ceramic matrix composites (SiCSiC CMCs) offer high payoff as replacements for metals in turbine engine applications due to their lighter weight, higher temperature capability, and lower cooling requirements. Additive manufacturing approaches can offer game changing technologies for the quick and low cost fabrication of parts with much greater design freedom and geometric complexity. Four approaches for developing these materials are presented. The first two utilize low cost 3D printers. The first uses pre-ceramic pastes developed as feed materials which are converted to SiC after firing. The second uses wood containing filament to print a carbonaceous preform which is infiltrated with a pre-ceramic polymer and converted to SiC. The other two approaches pursue the AM of CMCs. The first is binder jet SiC powder processing in collaboration with rp+m (Rapid Prototyping+Manufacturing). Processing optimization was pursued through SiC powder blending, infiltration with and without SiC nano powder loading, and integration of nanofibers into the powder bed. The second approach was laminated object manufacturing (LOM) in which fiber prepregs and laminates are cut to shape by a laser and stacked to form the desired part. Scanning electron microscopy was conducted on materials from all approaches with select approaches also characterized with XRD, TGA, and bend testing.

  8. Improved Foreign Object Damage Performance for 3D Woven Ceramic Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As the power density of advanced engines increases, the need for new materials that are capable of higher operating temperatures, such as ceramic matrix composites...

  9. Improved Foreign Object Damage Performance for 2D Woven Ceramic Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As the power density of advanced engines increases, the need for new materials that are capable of higher operating temperatures, such as ceramic matrix composites...

  10. Ceramic Composite Mechanical Fastener System for High-Temperature Structural Assemblies Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hot structures fabricated from ceramic composite materials are an attractive design option for components of future high-speed aircraft, re-entry vehicles and...

  11. Complex oxide with negative thermal expansion for producing ceramic matrix composites with invar effect

    Science.gov (United States)

    Dedova, Elena S.; Pertushina, Mariya U.; Kondratenko, Anton I.; Gorev, Mikhail V.; Kulkov, Sergei N.

    2016-11-01

    The article investigates the phase composition of (Al2O3-20 wt % ZrO2)-ZrW2O8 ceramic composites obtained by cold-pressing and sintering processes. Using X-ray analysis it has been shown that composites mainly have monoclinic modification of zirconium dioxide and orthorhombic phase of aluminum oxide. After adding zirconium tungstate the phase composition of sintered ceramics changes, followed by the formation of tungsten-aluminates spinel such as Alx(WOy)z. It has been shown that thermal expansion coefficient of material decreases approximatly by 30%, as compared with initial ceramics.

  12. Interpenetrating phase ceramic/polymer composite coatings: Fabrication and characterization

    Science.gov (United States)

    Craig, Bradley Dene

    The goals of this thesis research were to fabricate interpenetrating phase composite (IPC) ceramic/polymer coatings and to investigate the effect of the interconnected microstructure on the physical and wear properties of the coatings. IPC coatings with an interpenetrating phase microstructure were successfully fabricated by first forming a porous ceramic with an interconnected microstructure using a chemical bonding route (mainly reacting alpha-alumina (0.3 mum) with orthophosphoric acid to form a phosphate bond). Porosity within these ceramic coatings was easily controlled between 20 and 50 vol. % by phosphoric acid addition, and was measured by a new porosity measurement technique (thermogravimetric volatilization of liquids, or TVL) which was developed. The resulting ceramic preforms were infiltrated with a UV and thermally curable cycloaliphatic epoxide resin and cured. This fabrication route resulted in composite coatings with thicknesses ranging from ˜1mum to 100 mum with complete filling of open pore space. The physical properties of the composite coatings, including microhardness, flexural modulus and wear resistance, were evaluated as a function of processing variables, including orthophosphoric acid content and ceramic phase firing temperature, which affected the microstructure and interparticulate bonding between particles in the coatings. For example, microhardness increased from ˜30 on the Vicker's scale to well over 200 as interparticulate bonding was increased in the ceramic phase. Additionally, Taber wear resistance in the best TPC coatings was found to approach that of fully-densified alumina under certain conditions. Several factors were found to influence the wear mechanism in the IPC coating materials. Forming strong connections between ceramic particles led to up to an order of magnitude increase in the wear resistance. Additionally, coating microhardness and ceramic/polymer interfacial strength were studied and found to be important in

  13. A Model for Estimating Nonlinear Deformation and Damage in Ceramic Matrix Composites (Preprint)

    Science.gov (United States)

    2011-07-01

    AFRL-RX-WP-TP-2011-4232 A MODEL FOR ESTIMATING NONLINEAR DEFORMATION AND DAMAGE IN CERAMIC MATRIX COMPOSITES (PREPRINT) Unni Santhosh and...5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR(S) Unni Santhosh and Jalees Ahmad 5d. PROJECT...Composite Materials, 2010 A Model for Estimating Nonlinear Deformation and Damage in Ceramic Matrix Composites Unni Santhosh and Jalees Ahmad Research

  14. Chemical Composition of Ceramic Tile Glazes

    Science.gov (United States)

    Anufrik, S. S.; Kurian, N. N.; Zhukova, I. I.; Znosko, K. F.; Belkov, M. V.

    2016-11-01

    We have carried out laser emission and x-ray fluorescence spectral analysis of glaze before and after its application to ceramic tile produced by Keramin JSC (Belarus). We have studied the internal microstructure of the ceramic samples. It was established that on the surface and within the bulk interior of all the samples, there are micropores of sizes ranging from a few micrometers to tens of micrometers and microcracks as long as several hundred micrometers. The presence of micropores on the surface of the ceramic tile leads to an increase in the water absorption level and a decrease in frost resistance. It was found that a decrease in the surface tension of ceramic tile coatings is promoted by substitution of sodium by potassium, silica by boric anhydride, magnesium and barium by calcium, CaO by sodium oxide, and SiO2 by chromium oxide. We carried out a comparative analysis of the chemical composition of glaze samples using S4 Pioneer and ElvaX x-ray fluorescence spectrometers and also an LIBS laser emission analyzer.

  15. PMMA-based composite materials with reactive ceramic fillers: IV. Radiopacifying particles embedded in PMMA beads for acrylic bone cements.

    Science.gov (United States)

    Abboud, M; Casaubieilh, L; Morvan, F; Fontanille, M; Duguet, E

    2000-01-01

    New acrylic bone cements were prepared from alumina particles previously treated by 3-(trimethoxysilyl)propylmethacrylate (gamma-MPS) and embedded in poly(methylmethacrylate-co-ethylacrylate) beads with about 7 mol% of ethyl acrylate repeating units. The encapsulation was performed through a conventional suspension polymerization process. The influence of (i) the concentration of the dispersion stabilizer and (ii) the alumina content upon the shape, size, and size distribution of the acrylic beads was studied. Cements were prepared from each batch by hand-mixing alumina-filled acrylic beads with a liquid monomer mixture containing methyl methacrylate, n-butyl methacrylate, and N,N-dimethyl-p-toluidine. Benzoyl peroxide was previously added to the solid part. The powder-to-liquid ratio was equal to 2 for each formulation. Compressive strength of cured cement decreases with alumina content, whereas compressive modulus remains roughly constant. These results are in contradiction to those obtained for cements based on a mixture of gamma-MPS-treated alumina and unfilled acrylic beads. Nevertheless, they are interpreted in terms of alumina arrangement in the cement. In the first case, alumina particles contribute to the reinforcement of the dispersed acrylic phase, with poor benefits for the whole materials. In the second case, they allow the reinforcement of the continuous acrylic phase and, therefore, the cement's one.

  16. Mullite-zirconium composites reinforced with ceramic fibres resistant to 1450 C; obtaining and properties

    Energy Technology Data Exchange (ETDEWEB)

    Cerchez, L.; Constantinescu, S. [PROCEMA S.A. Bucharest - Research, Design and Experimental Production, Bucharest (Romania). Inst. for Construction and Construction Materials; Muntean, M. [Universitatea Politehnica, Bucharest (Romania). Faculty of Industrial Chemistry

    2002-07-01

    The purpose of this paper was the obtaining of some mullite-zirconium matrix composites, reinforced with ceramic fibres resistant to 1450 C. In order to establish the compositions, the raw materials were ground, depending on their nature, in many ways, and there were established the characteristics of ground resulted powders. On the obtained materials it was followed the evolution of the ceramic, mechanical and structural characteristics, depending on the heat treatment temperature, for various reinforcing coefficients. (orig.)

  17. Stereological characterization of crack path transitions in ceramic matrix composites

    Indian Academy of Sciences (India)

    Parag Bhargava; B R Patterson

    2001-04-01

    All ceramic composites involve a mismatch in physical properties the extent of which differs from one composite to another. Mismatch in thermal expansion ( ) and elastic modulus (E) is known to produce stresses that influence the path of a propagating crack. Thus, the relative effect of thermal and elastic mismatch on the crack path is expected to change with change in stress intensity. We propose that the crack path in ceramic composites should undergo a transition with the crack being strongly influenced by the thermal mismatch stresses at low stress intensity and elastic mismatch stresses at high stress intensities. Thus, a material in use under different applications each with its own loading conditions is expected to exhibit different crack propagation tendencies which may be reflected in the – characteristics of the composite material. In the present work several model composites with different combinations of thermal and elastic mismatch have been considered. Cracks propagating at different sub-critical stress intensities (velocities) were generated by a novel indentation technique. Each indentation was performed at a constant displacement rate and a peak load. A range of displacement rates were used to produce cracks propagating at different velocities. The indentations were made using a Vickers indentor fitted in a universal mechanical testing machine. The crack paths in composites were quantified by stereological technique and the proposed theory was verified.

  18. Magnetic Resonance Imaging of Gel-cast Ceramic Composites

    Science.gov (United States)

    Dieckman, S. L.; Balss, K. M.; Waterfield, L. G.; Jendrzejczyk, J. A.; Raptis, A. C.

    1997-01-16

    Magnetic resonance imaging (MRI) techniques are being employed to aid in the development of advanced near-net-shape gel-cast ceramic composites. MRI is a unique nondestructive evaluation tool that provides information on both the chemical and physical properties of materials. In this effort, MRI imaging was performed to monitor the drying of porous green-state alumina - methacrylamide-N.N`-methylene bisacrylamide (MAM-MBAM) polymerized composite specimens. Studies were performed on several specimens as a function of humidity and time. The mass and shrinkage of the specimens were also monitored and correlated with the water content.

  19. Summary of workshop on ceramic composite interface coatings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    Commercialization of fiber-reinforced composites has been limited because of the stability of the interface coatings that control the mechanical properties of the composites. Typical materials are currently manufactured with pyrolytic carbon interface coatings that perform well in inert atmospheres or when stresses are kept very low (<70 MPa). Unfortunately, carbon coatings are not stable at high temperatures in air or oxidizing conditions which results in degradation of the mechanical properties of the composites. The problem of oxidation resistant interface coatings is not unique to the Fossil Program. Such coatings are also a concern to the United States Air Force, the Continuous Fiber-reinforced Ceramic Composites Program, the Fusion Energy Materials Program, and to the European Community. This workshop was organized to compare and discuss the need for and development of oxidation-resistant interface coatings in each of these programs.

  20. Melt Infiltrated Ceramic Composites (Hipercomp) for Gas Turbine Engine Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Corman; Krishan Luthra

    2005-09-30

    This report covers work performed under the Continuous Fiber Ceramic Composites (CFCC) program by GE Global Research and its partners from 1994 through 2005. The processing of prepreg-derived, melt infiltrated (MI) composite systems based on monofilament and multifilament tow SiC fibers is described. Extensive mechanical and environmental exposure characterizations were performed on these systems, as well as on competing Ceramic Matrix Composite (CMC) systems. Although current monofilament SiC fibers have inherent oxidative stability limitations due to their carbon surface coatings, the MI CMC system based on multifilament tow (Hi-Nicalon ) proved to have excellent mechanical, thermal and time-dependent properties. The materials database generated from the material testing was used to design turbine hot gas path components, namely the shroud and combustor liner, utilizing the CMC materials. The feasibility of using such MI CMC materials in gas turbine engines was demonstrated via combustion rig testing of turbine shrouds and combustor liners, and through field engine tests of shrouds in a 2MW engine for >1000 hours. A unique combustion test facility was also developed that allowed coupons of the CMC materials to be exposed to high-pressure, high-velocity combustion gas environments for times up to {approx}4000 hours.

  1. Study on Effects of Alkylation Modification on Properties of Quartz Composite Ceramic Materials%烷基化改性对石英复合陶瓷材料性能的影响研究

    Institute of Scientific and Technical Information of China (English)

    尹正帅; 刘义华; 王芬; 佘平江; 袁孟春

    2015-01-01

    Quartz composite ceramic material is alkylated modified by using HMDS. Mechanical properties, humidity resistance, dielectric properties, oxyacetylene ablation properties and adhesion properties of the materials are investigated. The results show that the alkylation modification can greatly improve humidity resistance of quartz composite ceramic material, slightly improve dielectric properties, oxyacetylene ablation properties and adhesion properties of the materials, and has no effect on mechanical properties of the materials.%采用六甲基二硅氮烷对石英复合陶瓷进行烷基化改性,研究了烷基化改性前后材料的力学性能、吸潮性能、介电性能、氧乙炔烧蚀性能及粘接性能.结果显示,烷基化改性能够极大地改善石英复合陶瓷材料的防潮性能,对介电性能和氧乙炔线烧蚀率和粘接性能略有提升,对力学性能基本无影响.

  2. Constitutive Theory Developed for Monolithic Ceramic Materials

    Science.gov (United States)

    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

  3. Preparation of Machinable Y-TZP/LaPO4 Composite Ceramics by Liquid Precursor Infiltration

    Institute of Scientific and Technical Information of China (English)

    周振君; 杨正方; 袁启明; 李秀华

    2002-01-01

    A machinable Y-TZP/LaPO4 composite ceramic was prepared by infiltrating LaPO4 liquid precursor into Y-TZP porous ceramic. Sintered Y-TZP ceramic preformed with 35% (volume fraction) open pore volume was made by adding graphite (30%, volume fraction). The Y-TZP/LaPO4 composite ceramics containing different LaPO4 contents were obtained by infiltration and pyrolysis cycles. The machinability and mechanical properties of materials were investigated. The results show that the machinable Y-TZP/LaPO4 composite ceramics containing 2.3% to 7.5% (volume fraction) LaPO4 has good machinability as well as outstanding mechanical properties.

  4. Conductive ceramic composition and method of preparation

    Science.gov (United States)

    Smith, J.L.; Kucera, E.H.

    1991-04-16

    A ceramic anode composition is formed of a multivalent metal oxide or oxygenate such as an alkali metal, transition metal oxygenate. The anode is prepared as a non-stoichiometric crystalline structure by reaction and conditioning in a hydrogen gas cover containing minor proportions of carbon dioxide and water vapor. The structure exhibits a single phase and substantially enhanced electrical conductivity over that of the corresponding stoichiometric structure. Unexpectedly, such oxides and oxygenates are found to be stable in the reducing anode fuel gas of a molten carbonate fuel cell. 4 figures.

  5. A mechanical model for surface layer formation on self-lubricating ceramic composites

    NARCIS (Netherlands)

    Song, Jiupeng; Valefi, Mahdiar; Rooij, de Matthijn; Schipper, Dirk J.

    2010-01-01

    To predict the thickness of a self-lubricating layer on the contact surface of ceramic composite material containing a soft phase during dry sliding test, a mechanical model was built to calculate the material transfer of the soft second phase in the composite to the surface. The tribological test,

  6. Improved C/SiC Ceramic Composites Made Using PIP

    Science.gov (United States)

    Easler, Timothy

    2007-01-01

    Improved carbon-fiber-reinforced SiC ceramic-matrix composite (C/SiC CMC) materials, suitable for fabrication of thick-section structural components, are producible by use of a combination of raw materials and processing conditions different from such combinations used in the prior art. In comparison with prior C/SiC CMC materials, these materials have more nearly uniform density, less porosity, and greater strength. The majority of raw-material/processing-condition combinations used in the prior art involve the use of chemical vapor infiltration (CVI) for densifying the matrix. In contrast, in synthesizing a material of the present type, one uses a combination of infiltration with, and pyrolysis of, a preceramic polymer [polymer infiltration followed by pyrolysis (PIP)]. PIP processing is performed in repeated, tailored cycles of infiltration followed by pyrolysis. Densification by PIP processing takes less time and costs less than does densification by CVI. When one of these improved materials was tested by exposure to a high-temperature, inert-gas environment that caused prior C/SiC CMCs to lose strength, this material did not lose strength. (Information on the temperature and exposure time was not available at the time of writing this article.) A material of the present improved type consists, more specifically, of (1) carbon fibers coated with an engineered fiber/matrix interface material and (2) a ceramic matrix, containing SiC, derived from a pre-ceramic polymer with ceramic powder additions. The enhancements of properties of these materials relative to those of prior C/SiC CMC materials are attributable largely to engineering of the fiber/ matrix interfacial material and the densification process. The synthesis of a material of this type includes processing at an elevated temperature to a low level of open porosity. The approach followed in this processing allows one to fabricate not only simple plates but also more complexly shaped parts. The carbon fiber

  7. FRACTURE MECHANICS STUDY OF CERAMIC-CERAMIC COMPOSITES

    OpenAIRE

    1986-01-01

    The materials used in this study are silica matrix composites reinforced with short random Nextel or SiC fibers. The tests to determine the crack propagation resistance curves are performed on SENB specimens and analysed in the case of non linear behaviour (JR curves).

  8. Wear and Reactivity Studies of Melt infiltrated Ceramic Matrix Composite

    Science.gov (United States)

    Jarmon, David C.; Ojard, Greg; Brewer, David N.

    2013-01-01

    As interest grows in the use of ceramic matrix composites (CMCs) for critical gas turbine engine components, the effects of the CMCs interaction with the adjoining structure needs to be understood. A series of CMC/material couples were wear tested in a custom elevated temperature test rig and tested as diffusion couples, to identify interactions. Specifically, melt infiltrated silicon carbide/silicon carbide (MI SiC/SiC) CMC was tested in combination with a nickel-based super alloy, Waspaloy, a thermal barrier coating, Yttria Stabilized Zirconia (YSZ), and a monolithic ceramic, silicon nitride (Si3N4). To make the tests more representative of actual hardware, the surface of the CMC was kept in the as-received state (not machined) with the full surface features/roughness present. Test results include: scanning electron microscope characterization of the surfaces, micro-structural characterization, and microprobe analysis.

  9. Design Concepts for Cooled Ceramic Matrix Composite Turbine Vanes

    Science.gov (United States)

    Boyle, Robert

    2014-01-01

    This project demonstrated that higher temperature capabilities of ceramic matrix composites (CMCs) can be used to reduce emissions and improve fuel consumption in gas turbine engines. The work involved closely coupling aerothermal and structural analyses for the first-stage vane of a high-pressure turbine (HPT). These vanes are actively cooled, typically using film cooling. Ceramic materials have structural and thermal properties different from conventional metals used for the first-stage HPT vane. This project identified vane configurations that satisfy CMC structural strength and life constraints while maintaining vane aerodynamic efficiency and reducing vane cooling to improve engine performance and reduce emissions. The project examined modifications to vane internal configurations to achieve the desired objectives. Thermal and pressure stresses are equally important, and both were analyzed using an ANSYS® structural analysis. Three-dimensional fluid and heat transfer analyses were used to determine vane aerodynamic performance and heat load distributions.

  10. Toughening and strengthening of ceramics composite through microstructural refinement

    Science.gov (United States)

    Anggraini, Lydia; Isonishi, Kazuo; Ameyama, Kei

    2016-04-01

    Silicon carbide with 50 mass% zirconia ceramic matrix composites were processed by mechanical milling (MM) followed by spark plasma sintering (SPS). By controlling the parameters of MM and SPS, an ultra-fine ZrO2 grain was homogeneously dispersed and refined on the surface of a fine SiC powder, forming a harmonic microstructure. The mechanical properties and the densification behavior of the SiC-ZrO2 composites were investigated. The effects of the milling time on the microstructure and on the mechanical properties of the composite are discussed. The results indicate that the composite mechanically milled for 144 ks and sintered at 1773 K had the highest relative density of 98 %, along with a fracture toughness of 10.7 MPa.m1/2 and a bending strength of 1128 MPa. These superior mechanical properties were influenced by the microstructure characteristics such as the homogeneous grain dispersion. Thus, the microstructural refinement forming harmonic dispersion can be considered a remarkable design tool for improving the mechanical properties of SiC-ZrO2, as well as other ceramic composite materials.

  11. Randomized Clinical Trial of Indirect Resin Composite and Ceramic Veneers : Up to 3-year Follow-up

    NARCIS (Netherlands)

    Gresnigt, Marco M. M.; Kalk, Warner; Ozcan, Mutlu

    2013-01-01

    Purpose: This randomized controlled split-mouth clinical trial evaluated the short-term survival rate of indirect resin composite and ceramic laminate veneers. Materials and Methods: A total of 10 patients (mean age: 48.6 years) received 46 indirect resin composite (Estenia; n = 23) and ceramic lami

  12. Compositional Optimum Design and Experimental Investigation of Rare Earth Containing Ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    Xu Chonghai; Huang Chuanzhen; Ai Xing

    2004-01-01

    Based on the Al2O3/(W,Ti) C ceramic material, optimum design of the material compositions were carried out, which includes the theoretical calculation of the critical volume fraction of the reinforcement phase, and the optimum design based on the impact resistance, thermal shock resistance and wear resistance, etc. It is found that the optimum volume fraction of (W,Ti)C is 31.2%, 32.8% and 34%, respectively, which is corresponding with the best impact resistance, thermal shock resistance and wear resistance. After comprehensive consideration, the optimum volume fraction of (W,Ti)C in Al2O3/( W, Ti)C ceramic material is finally determined to be 30%. Then, effects of the content of rare earth yttrium on the mechanical property of the Al2O3/30vol% (W,Ti)C ceramic material were investigated experimentally. It indicates that when the content of yttrium is 0.25% ~ 0.5%, both flexural strength and fracture toughness of the rare earth containing ceramic material are further improved with the increment of approximately 10% ~16%.

  13. Analysis of Material Removal in Alumina Ceramic Honing

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The removal mechanism is of importance to the grinding of hard and brittle ceramic materials. It is more suitable to analyze the material removal during ceramics honing processes by means of indention fracture approach. There are two honing characteristics different from grinding, the honing incidental tensile stresses and the crosshatch pattern. The stresses may influence material removal of brittle ceramics with lower tensile strength. In addition, the criss-cross cutting pattern on a bore known as cros...

  14. Nano-composite materials

    Science.gov (United States)

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  15. Nondestructive damage evaluation in ceramic matrix composites for aerospace applications.

    Science.gov (United States)

    Dassios, Konstantinos G; Kordatos, Evangelos Z; Aggelis, Dimitrios G; Matikas, Theodore E

    2013-01-01

    Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately.

  16. Multifunctional Composite Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Polymeric composite materials that are currently utilized in aircraft structures are susceptible to significant damage from lightning strikes. Enhanced electrical...

  17. Update on CMH-17 Volume 5: Ceramic Matrix Composites

    Science.gov (United States)

    David, Kaia; Pierce, Jennifer; Kiser, James; Keith, William P.; Wilson, Gregory S.

    2015-01-01

    CMC components are projected to enter service in commercial aircraft in 2016. A wide range of issues must be addressed prior to certification of this hardware. The Composite Materials Handbook-17, Volume 5 on ceramic matrix composites is being revised to support FAA certification of CMCs for hot structure and other elevated temperature applications. The handbook supports the development and use of CMCs through publishing and maintaining proven, reliable engineering information and standards that have been thoroughly reviewed. Volume 5 will contain detailed sections describing CMC materials processing, design analysis guidelines, testing procedures, and data analysis and acceptance. A review of the status of and plans for two of these areas, which are being addressed by the M and P Working Group and the Testing Working Group, will be presented along with a timeline for the preparation of CMH-17, Volume 5.

  18. Processes for fabricating composite reinforced material

    Energy Technology Data Exchange (ETDEWEB)

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2015-11-24

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  19. Implementation Challenges for Sintered Silicon Carbide Fiber Bonded Ceramic Materials for High Temperature Applications

    Science.gov (United States)

    Singh, M.

    2011-01-01

    During the last decades, a number of fiber reinforced ceramic composites have been developed and tested for various aerospace and ground based applications. However, a number of challenges still remain slowing the wide scale implementation of these materials. In addition to continuous fiber reinforced composites, other innovative materials have been developed including the fibrous monoliths and sintered fiber bonded ceramics. The sintered silicon carbide fiber bonded ceramics have been fabricated by the hot pressing and sintering of silicon carbide fibers. However, in this system reliable property database as well as various issues related to thermomechanical performance, integration, and fabrication of large and complex shape components has yet to be addressed. In this presentation, thermomechanical properties of sintered silicon carbide fiber bonded ceramics (as fabricated and joined) will be presented. In addition, critical need for manufacturing and integration technologies in successful implementation of these materials will be discussed.

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

    Science.gov (United States)

    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.

  1. Development of Al2O3/TiN Ceramic Cutting Tool Materials by Artificial Neural Networks

    Institute of Scientific and Technical Information of China (English)

    Ning FAN; Xiangbo ZE; Zihui GAO

    2004-01-01

    The artificial neural networks (ANN) which have broad application were proposed to develop multiphase ceramic cutting tool materials. Based on the back propagation algorithm of the forward multilayer perceptron, the models to predict volume content of composition in particle reinforced ceramics are established. The Al2O3/TiNl ceramic cutting tool material was developed by ANN, whose mechanical properties fully satisfy the cutting requirements.

  2. Nondestructive Characterization of As-Fabricated Composite Ceramic Panels

    Science.gov (United States)

    Green, W. H.; Brennan, R. E.

    2011-06-01

    Decreasing the weight of protective systems, while minimizing the decrease in ballistic performance, is an ongoing goal of the Army. Ceramic materials are currently combined with other materials in these types of structures in order to decrease weight without losing ballistic performance. This includes structures in which the ceramic material is confined in some way and in which the ceramic material is completely encapsulated. Confinement or encapsulation of ceramic material within a structure generally adds complexity and cost. Relatively simple panel specimens fabricated with ceramic tiles on aluminum backings and side confinement using steel were evaluated using nondestructive methods, including x-ray computed tomography and ultrasonic testing. The nondestructive evaluation results will be discussed and compared, including the detectability and mapping of fabrication features.

  3. Micromechanics-Based Computational Simulation of Ceramic Matrix Composites

    Science.gov (United States)

    Murthy, Pappu L. N.; Mutal, Subodh K.; Duff, Dennis L. (Technical Monitor)

    2003-01-01

    Advanced high-temperature Ceramic Matrix Composites (CMC) hold an enormous potential for use in aerospace propulsion system components and certain land-based applications. However, being relatively new materials, a reliable design properties database of sufficient fidelity does not yet exist. To characterize these materials solely by testing is cost and time prohibitive. Computational simulation then becomes very useful to limit the experimental effort and reduce the design cycle time, Authors have been involved for over a decade in developing micromechanics- based computational simulation techniques (computer codes) to simulate all aspects of CMC behavior including quantification of scatter that these materials exhibit. A brief summary/capability of these computer codes with typical examples along with their use in design/analysis of certain structural components is the subject matter of this presentation.

  4. Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications

    Directory of Open Access Journals (Sweden)

    Konstantinos G. Dassios

    2013-01-01

    Full Text Available Infrared thermography (IRT and acoustic emission (AE are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material’s performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately.

  5. Combustion synthesis of advanced composite materials

    Science.gov (United States)

    Moore, John J.

    1993-01-01

    Self-propagating high temperature (combustion) synthesis (SHS), has been investigated as a means of producing both dense and expanded (foamed) ceramic and ceramic-metal composites, ceramic powders and whiskers. Several model exothermic combustion synthesis reactions were used to establish the importance of certain reaction parameters, e.g., stoichiometry, green density, combustion mode, particle size, etc. on the control of the synthesis reaction, product morphology and properties. The use of an in situ liquid infiltration technique and the effect of varying the reactants and their stoichiometry to provide a range of reactant and product species i.e., solids, liquids and gases, with varying physical properties e.g., volatility and thermal conductivity, on the microstructure and morphology of synthesized composite materials is discussed. Conducting the combustion synthesis reaction in a reactive gas environment to take advantage of the synergistic effects of combustion synthesis and vapor phase transport is also examined.

  6. Friction Material Composites Materials Perspective

    CERN Document Server

    Sundarkrishnaa, K L

    2012-01-01

    Friction Material Composites is the first of the five volumes which strongly educates and updates engineers and other professionals in braking industries, research and test labs. It explains besides the formulation of design processes and its complete manufacturing input. This book gives an idea of mechanisms of friction and how to control them by designing .The book is  useful for designers  of automotive, rail and aero industries for designing the brake systems effectively with the integration of friction material composite design which is critical. It clearly  emphasizes the driving  safety and how serious designers should  select the design input. The significance of friction material component like brake pad or a liner as an integral part of the brake system of vehicles is explained. AFM pictures at nanolevel illustrate broadly the explanations given.

  7. Effect of Microwave Heating on Infrared Radiation Properties of Cordierite-Ferrites Based Composite Ceramics

    Institute of Scientific and Technical Information of China (English)

    LU; Lei; FAN; Xi’an; HU; Xiaoming; ZHANG; Jianyi

    2015-01-01

    The cordierite-ferrites based infrared radiation composite materials were synthesized with Fe2O3, Mn O2, Cu O, Co2O3, and Mg2Al4Si5O18 powders as raw materials via microwave heating. The cordierite-ferrites based composite ceramics could be obtained via microwave heating at 1173 K for 1 h or 1473 K for 10 min, respectively. The lower synthesis temperature or the shorter heating time results in the smaller grain size of the composite ceramics obtained by microwave heating. The interplanar distance of cordierite becomes greater after microwave heating, indicating that the doping effect of transitional metal oxides on the cordierite is more efficient in microwave heating. The infrared radiation composite ceramics synthesized by microwave heating at 1473 K for 1 h exhibit the maximum emissivity of 0.9 in the band range of 6-8 μm at 1073 K.

  8. Superplasticity in ceramic and metal matrix composites and the role of grain size, segregation, interfaces, and second phase morphology

    Energy Technology Data Exchange (ETDEWEB)

    Wadsworth, J.; Nieh, T.G.

    1992-10-01

    Structural ceramics and ceramic composites have been shown to exhibit superplasticity in recent times and this discovery has attracted tremendous interest. Although the number of ceramics exhibits superplasticity is now quite large, there are gaps in understanding the requirements for superplasticity in ceramics. Also, superplastic behavior at very high strain rates (1 s{sup {minus}1}) in metallic-based materials is an area of increasing research. In this case, the phenomenon has been observed quite extensively in aluminum alloy-based metal matrix composites and mechanically alloyed aluminum- and nickel-based materials. Again, the details of the structural requirements of this phenomenon are not yet understood. In the present paper, experimental results on superplasticity in ceramic-based materials and on high strain rate behavior in metallic-based materials are presented. The roles of grain size, grain boundary and interface chemistry, and second phase morphology and compatibility with the matrix material will be emphasized.

  9. Biocompatible glass-ceramic materials for bone substitution.

    Science.gov (United States)

    Vitale-Brovarone, Chiara; Verné, Enrica; Robiglio, Lorenza; Martinasso, Germana; Canuto, Rosa A; Muzio, Giuliana

    2008-01-01

    A new bioactive glass composition (CEL2) in the SiO(2)-P(2)O(5)-CaO-MgO-K(2)O-Na(2)O system was tailored to control pH variations due to ion leaching phenomena when the glass is in contact with physiological fluids. CEL2 was prepared by a traditional melting-quenching process obtaining slices that were heat-treated to obtain a glass-ceramic material (CEL2GC) that was characterized thorough SEM analysis. Pre-treatment of CEL2GC with SBF was found to enhance its biocompatibility, as assessed by in vitro tests. CEL2 powder was then used to synthesize macroporous glass-ceramic scaffolds. To this end, CEL2 powders were mixed with polyethylene particles within the 300-600 microm size-range and then pressed to obtain crack-free compacted powders (green). This was heat-treated to remove the organic phase and to sinter the inorganic phase, leaving a porous structure. The biomaterial thus obtained was characterized by X-ray diffraction, SEM equipped with EDS, density measurement, image analysis, mechanical testing and in vitro evaluation, and found to be a glass-ceramic macroporous scaffold with uniformly distributed and highly interconnected porosity. The extent and size-range of the porosity can be tailored by varying the amount and size of the polyethylene particles.

  10. Use of basaltic waste as red ceramic raw material

    Directory of Open Access Journals (Sweden)

    T. M. Mendes

    Full Text Available Abstract Nowadays, environmental codes restrict the emission of particulate matters, which result in these residues being collected by plant filters. This basaltic waste came from construction aggregate plants located in the Metropolitan Region of Londrina (State of Paraná, Brazil. Initially, the basaltic waste was submitted to sieving (< 75 μm and the powder obtained was characterized in terms of density and particle size distribution. The plasticity of ceramic mass containing 0%, 10%, 20%, 30%, 40% and 50% of basaltic waste was measured by Atterberg method. The chemical composition of ceramic formulations containing 0% and 20% of basaltic waste was determined by X-ray fluorescence. The prismatic samples were molded by extrusion and fired at 850 °C. The specimens were also tested to determine density, water absorption, drying and firing shrinkages, flexural strength, and Young's modulus. Microstructure evaluation was conducted by scanning electron microscopy, X-ray diffraction, and mercury intrusion porosimetry. Basaltic powder has similar physical and chemical characteristics when compared to other raw materials, and contributes to ceramic processing by reducing drying and firing shrinkage. Mechanical performance of mixtures containing basaltic powder is equivalent to mixtures without waste. Microstructural aspects such as pore size distribution were modified by basaltic powder; albite phase related to basaltic powder was identified by X-ray diffraction.

  11. Characterizing damage in ceramic matrix composites

    Science.gov (United States)

    Gyekenyesi, Andrew L.; Baker, Christopher; Morscher, Gregory

    2014-04-01

    With the upcoming implementation of ceramic matrix composites (CMCs) within aerospace systems (e.g., aviation turbine engines), an in-depth understanding of the failure process due to mechanical loads is required. This includes developing a basic understanding of the complex, multi-mechanism failure process as well as the associated nondestructive evaluation (NDE) techniques that are capable of recognizing and quantifying the damage. Various NDE techniques have been successfully utilized for assessing the damage state of woven CMCs, in particular, consisting of silicon carbide fibers and silicon carbide matrices (SiC/SiC). The multiple NDE techniques, studied by the authors of this paper, included acousto-ultrasonics, modal acoustic emissions, electrical resistance, impedance based structural health monitoring, pulsed thermography as well as thermoelastic stress analysis. The observed damage within the composites was introduced using multiple experimental tactics including uniaxial tensile tests, creep tests, and most recently, ballistic impact. This paper offers a brief review and summary of results for each of the applied NDE tools.

  12. Chemical composition of the clays as indicator raw material sources

    Directory of Open Access Journals (Sweden)

    Khramchenkova Rezida Kh

    2014-06-01

    Full Text Available The paper presents the results of study on the chemical composition of unglazed pottery from the excavations of the Bulgar fortified settlement site and the clay, selected from the modern deposits of ceramic raw materials located near the medieval settlement sites. Significant differences in macro- and microelement composition of different groups of ceramics have been revealed. The difference in the macroelemental composition is largely determined by the ceramic fabric recipe. Thus, the high calcium content corresponds to the addition of river shells, the high content of silicon results from sand addition. A more interesting picture has been revealed in the course of studies of the so-called “trace elements” (microelements. Nine groups of ceramics with different elemental set have been distinguished. The first two groups consist of imported ceramics; other groups have demonstrated a rather pronounced elemental composition. The most notable variations are observed in chromium, vanadium and nickel content. Similar microelement composition variety has been observed in clays from deposits of different localization, while the concentration of the mentioned elements in a variety of clays also differs considerably. Therefore, marker elements typical of different clays have been identified. A comparative analysis of the data obtained for clay raw materials and ceramics has been conducted. The results demonstrate the potential of studying the elemental composition in order to determine the localization of the raw material sources for ceramic production.

  13. Laser Machining of Melt Infiltrated Ceramic Matrix Composite

    Science.gov (United States)

    Jarmon, D. C.; Ojard, G.; Brewer, D.

    2012-01-01

    As interest grows in considering the use of ceramic matrix composites for critical components, the effects of different machining techniques, and the resulting machined surfaces, on strength need to be understood. This work presents the characterization of a Melt Infiltrated SiC/SiC composite material system machined by different methods. While a range of machining approaches were initially considered, only diamond grinding and laser machining were investigated on a series of tensile coupons. The coupons were tested for residual tensile strength, after a stressed steam exposure cycle. The data clearly differentiated the laser machined coupons as having better capability for the samples tested. These results, along with micro-structural characterization, will be presented.

  14. Modeling oxidation damage of continuous fiber reinforced ceramic matrix composites

    Institute of Scientific and Technical Information of China (English)

    Cheng-Peng Yang; Gui-Qiong Jiao; Bo Wang

    2011-01-01

    For fiber reinforced ceramic matrix composites (CMCs), oxidation of the constituents is a very important damage type for high temperature applications. During the oxidizing process, the pyrolytic carbon interphase gradually recesses from the crack site in the axial direction of the fiber into the interior of the material. Carbon fiber usually presents notch-like or local neck-shrink oxidation phenomenon, causing strength degradation. But, the reason for SiC fiber degradation is the flaw growth mechanism on its surface. A micromechanical model based on the above mechanisms was established to simulate the mechanical properties of CMCs after high temperature oxidation. The statistic and shearlag theory were applied and the calculation expressions for retained tensile modulus and strength were deduced, respectively. Meanwhile, the interphase recession and fiber strength degradation were considered. And then, the model was validated by application to a C/SiC composite.

  15. Design Concepts for Cooled Ceramic Matrix Composite Turbine Vanes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The work proposed herein is to demonstrate that the higher temperature capabilities of Ceramic Matrix Composites (CMC) can be fully utilized to reduce emissions and...

  16. Effect of prebonding procedures on shear bond strength of resin composite to pressable ceramic.

    Science.gov (United States)

    Estafan, D; Dussetschleger, F; Estafan, A; Jia, W

    2000-01-01

    Low bond strength between tooth structure and restorative ceramic material is a major cause of ceramic fractures or failures. Prebonding measures performed on pressable ceramic material were evaluated and the different shear bond strengths obtained by each method were tabulated. The three individual groups were subjected to 9% hydrofluoric (HF) acid gel for 0, 1, and 5 minutes. The different acid-etched time groups were chemically treated with silane coupler alone, silane coupling agent with bonding agent, and bonding agent alone. The silane coupling agent produced the highest bond strength between the composite structure and the pressable ceramic restorative material. High bond values were achieved by etching the porcelain for one minute. The use of the silane coupling agent with a one minute 9% HF acid etch yielded the greatest bond strength.

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

    Science.gov (United States)

    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

  18. Fundamental alloy design of oxide ceramics and their composites. [Annual] report, May 1, 1990--August 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Chen, I.W.

    1992-12-31

    The main research was on microstructural development of oxide ceramics. Projects were completed and the publications given. Abstracts are given on: Reactive CeO{sub 2}powders by homogeneous precipitation, SiC whisker-reinforced lithium aluminosilicate composite, solute drag on grain boundary in ionic solids (space charge effect), in-situ alumina/aluminate platelet composites, exaggerated texture and grain growth of superplastic silicon nitride (SiAlON), hot extrusion of ceramics, control of grain boundary pinning in Al{sub 2}O{sub 3}/ZrO{sub 2} composites with Ce{sup 3+}/Ce{sup 4+} doping, superplastic forming of ceramic composites, computer simulation of final stage sintering (model, kinetics, microstructure, effect of initial pore size), development of superplastic structural ceramics, and superplastic flow of two-phase ceramics containing rigid inclusions (zirconia/mullite composites). A proposed research program is outlined: materials, solute drag, densification and coarsening, and grain boundary electrical behavior.

  19. Metallic-fibre-reinforced ceramic-matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, F.; Schnedecker, G.; Boncoeur, M.

    1994-12-31

    A refractory metal wire cloth is embedded in an oxide ceramic matrix, using a plasma spraying technology, in order to elaborate composite plates. When mechanically tested, the composite fails with a pseudo-ductile fracture mode whereas the ceramic alone is originally brittle. It exhibits a higher fracture strength, and remains in the form of a single piece even when straining is important. No further heat treatment is needed after the original processing to reach these characteristics. (authors). 2 figs., 2 refs.

  20. Experimental 511 W Composite Nd:YAG Ceramic Laser

    Institute of Scientific and Technical Information of China (English)

    LI Hai-Feng; XU De-Gang; YANG Yang; WANG Yu-Ye; ZHOU Rui; ZHANG Tie-Li; ZHAO Xin; WANG Peng; YAO Jian-Quan

    2005-01-01

    @@ We demonstrate a 511 W laser diode pumped composite Nd:YAG ceramic laser. The optical pumping system is consisted of five laser diode stacked arrays arranged in a pentagonal shape around the ceramic rod whose size is φ6.35×144mm. When the pumping power is 1600W, the cw laser output up to 511 W at 1064nm can be obtained with a linear plano-plano cavity, and the optical-to-optical efficiency is 31.9%. To our knowledge, this is the highest value of laser output by using a newly invented composite Nd:YAG ceramic rod as the gain medium.

  1. Investigations on the sintering response of steel-ceramic composites

    Science.gov (United States)

    Baumgart, C.; Weigelt, C.; Krüger, L.; Aneziris, C. G.

    2016-07-01

    Purpose of this article is the evaluation of the influence of sintering parameters on the microstructure evolution and mechanical properties of pressureless sintered metal matrix composites consisting of metastable 16Cr7Mn7Ni-steel with 0 or 5 vol.% magnesia partially stabilized zirconia (Mg-PSZ) particles. The materials were prepared from powder raw materials via extrusion at ambient temperature. Three different temperatures between 1280 °C and 1380 °C and two varying dwell times of 40 min and 120 min at maximum temperature were applied. Both, tensile and compression tests are conducted at quasi-static strain rates for comparison of strength level, deformability and energy absorption capability. The results are discussed with regard to the porosity of the specimens, the interface between steel and ceramic, the TRansformation Induced Plasticity (TRIP)-effect occurrence and the failure behavior.

  2. Applications of the electron backscatter diffraction technique to ceramic materials

    Science.gov (United States)

    Koblischka, M. R.; Koblischka-Veneva, A.

    2013-07-01

    A technique with a relatively high spatial resolution is required for an effective analysis of the microstructure of ceramic materials. The recently developed electron backscatter diffraction (EBSD) technique, which works within a scanning electron microscope, enables a spatially highly resolved study of crystallographic orientations while recording Kikuchi patterns on a user-defined grid. However, such an EBSD texture analysis was until now not often performed on ceramic materials - in contrary, the technique is widely employed in the analysis of metallic materials, including the investigation of various types of steels. The use of ceramics possesses a variety of problems for EBSD investigations like: (i) complicated crystal structure, (ii) difficult surface preparation, and (iii) problems arising from a low conductivity of the ceramic materials. Here, we discuss these problems and present solutions in order to obtain high-quality Kikuchi patterns from such ceramics.

  3. Quantifying Effects of Voids in Woven Ceramic Matrix Composites

    Science.gov (United States)

    Goldsmith, Marlana B.; Sankar, Bhavani V.; Haftka, Raphael T.; Goldberg, Robert K.

    2013-01-01

    Randomness in woven ceramic matrix composite architecture has been found to cause large variability in stiffness and strength. The inherent voids are an aspect of the architecture that may cause a significant portion of the variability. A study is undertaken to investigate the effects of many voids of random sizes and distributions. Response surface approximations were formulated based on void parameters such as area and length fractions to provide an estimate of the effective stiffness. Obtaining quantitative relationships between the properties of the voids and their effects on stiffness of ceramic matrix composites are of ultimate interest, but the exploratory study presented here starts by first modeling the effects of voids on an isotropic material. Several cases with varying void parameters were modeled which resulted in a large amount of variability of the transverse stiffness and out-of-plane shear stiffness. An investigation into a physical explanation for the stiffness degradation led to the observation that the voids need to be treated as an entity that reduces load bearing capabilities in a space larger than what the void directly occupies through a corrected length fraction or area fraction. This provides explanation as to why void volume fraction is not the only important factor to consider when computing loss of stiffness.

  4. Thermal, mechanical and electrical properties of polyanaline based ceramic nano-composites

    Science.gov (United States)

    Sohail, M.; Khan, M. S.; Khattak, N. S.

    2016-08-01

    Micro/nanohybrid materials have vast applications due to their great potentialities in the field of nanoscience and nanotechnology. Herein we report an investigation on the fabrication and physicochemical characterization of ceramic (Fe0.01La0.01Al0.5Zn0.98O) and hybrid ceramic-polyaniline nano-composits. Ceramic nano-particles were prepared by sol-gel technique while optimizing the molar ratios of the constituent's metal nitrates. The prepared inorganic particles were then embedded in the polymer matrix via one-pot blending method. The prepared ceramic particles and their composites with polyaniline were analysed under FT- IR, SEM and TGA. The presence of some chemical species was observed at the interface of the compositing materials. TGA analysis showed the thermal stability of the composite material. Frequency dependent dielectric properties were analysed and it was found that conducting polyaniline has an additional effect on the electrical behaviour of the composite. Rheology study showed enhanced mechanical properties of composite material as compared to their constituting counterparts.

  5. Thermal shock resistance of ceramic fibre composites characterized by non-destructive methods

    Directory of Open Access Journals (Sweden)

    M. Dimitrijević

    2008-12-01

    Full Text Available Alumina based ceramic fibres and alumina based ceramic were used to produce composite material. Behaviour of composite ceramics after thermal shock treatments was investigated. Thermal shock of the samples was evaluated using water quench test. Surface deterioration level of samples was monitored by image analysis before and after a number of quenching cycles. Ultrasonic measurements were done on samples after quench tests. Dynamic Young modulus of elasticity and strength degradation were calculated using measured values of ultrasonic velocities. Strengths deterioration was calculated using the non-destructive measurements and correlated to degradation of surface area and number of quenches. The addition of small amount of ceramic fibres improves the strengths and diminishes the loss of mechanical properties of samples during thermal shock experiments.

  6. A novel biomimetic approach to the design of high-performance ceramic/metal composites

    Energy Technology Data Exchange (ETDEWEB)

    Launey, Maximilien E.; Munch, Etienne; Alsem, Daan Hein; Saiz, Eduardo; Tomsia, Antoni P.; Ritchie, Robert O.

    2009-08-01

    The prospect of extending natural biological design to develop new synthetic ceramic-metal composite materials is examined. Using ice-templating of ceramic suspensions and subsequent metal infiltration, we demonstrate that the concept of ordered hierarchical design can be applied to create fine-scale laminated ceramic-metal (bulk) composites that are inexpensive, lightweight and display exceptional damage-tolerance properties. Specifically, Al{sub 2}O{sub 3}/Al-Si laminates with ceramic contents up to approximately 40 vol% and with lamellae thicknesses down to 10 {micro}m were processed and characterized. These structures achieve an excellent fracture toughness of 40 MPa{radical}m at a tensile strength of approximately 300 MPa. Salient toughening mechanisms are described together with further toughening strategies.

  7. Synthesis and microstructure analysis of composite Nd: YAG/YAG transparent ceramics

    Institute of Scientific and Technical Information of China (English)

    Benxue Jiang; Tongde Huang; Yusong Wu; Wenbin Liu; Yubai Pan

    2009-01-01

    Transparent Nd:YAG/YAG composite ceramics are synthesized by solid-state reaction method using highpurity Y2O3,Al2O3,and Nd2O3 powders as raw materials.The mixed powder compacts are sintered at 1780 ℃ for 10 h under vacuum and annealed at 1450 ℃ for 20 h in air.The Nd:YAG/YAG ceramics exhibit a pore free structure with an average grain size of about 30 μm.The microstructure of the Nd:YAG/YAG composite transparent ceramics is studied and there is no interface between Nd:YAG and YAG ceramics.The Nd ion distribution in one grain is also studied,which shows that there is no segregation of Nd ions as in Nd:YAG crystals.

  8. Mechanical properties of ceramic composite tubes

    Energy Technology Data Exchange (ETDEWEB)

    Curtin, W.A.; Oleksuk, L.L.; Reifsnider, K.L. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Stinton, D.P. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Results of axial tension tests on SiC/SiC tubular ceramic composite components fabricated by a forced-M technique are presented. Axial elastic modulus measurements on a number of tubes show that the Young`s modulus varies along the length of the tube, with occasional very stiff or very soft regions. Tests to failure on a few tubes show the initiation of non-linear stress-strain behavior to be in the range of 3-9 ksi, followed by extensive non-linear deformation up to failure. For one tube, the failure stress obtained was 20.1 ksi, but the strains to failure at various axial locations varies from 0.19%to 0.24%. The correlation between modulus and proportional limit is considered within the ACK matrix cracking theory and within a model in which matrix cracking between fiber tows occurs, both modified to account for matrix porosity. The crack size required to cause stress concentrations large enough to cause failure at the observed strength is considered. Predictions for both matrix cracking and strength suggest that the current generation of tubes are controlled by microstructural defects.

  9. Thermo-mechanical performance of an ablative/ceramic composite hybrid thermal protection structure for re-entry applications

    OpenAIRE

    Triantou, K.; Mergia, K; Florez, S.; Perez, B.; Bárcena, Jorge; Rotärmel, W.; Pinaud, G.; Fischer, W.P.P.

    2015-01-01

    Hybrid thermal protection systems for aerospace applications based on ablative material (ASTERM (TM)) and ceramic matrix composite (SICARBON (TM)) have been investigated. The ablative material and the ceramic matrix composite were joined using graphite and zirconia zirconium silicate based commercial high temperature adhesives. The thermo-mechanical performance of the structures was assessed from room temperature up to 900 degrees C. In all the joints there is a decrease of shear strength wit...

  10. Glass-ceramics and epoxy-composites for radiation imaging

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.V.M. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand)], E-mail: G.Williams@irl.cri.nz; Bittar, A. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand); Dotzler, C. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand); School of Chemical and Physical Sciences, Victoria University, P.O. Box 600, Wellington (New Zealand); Beaudin, A. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand); Varoy, C. [School of Chemical and Physical Sciences, Victoria University, P.O. Box 600, Wellington (New Zealand); Dunford, C. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand)

    2007-04-15

    We report the results of optical, photo-luminescence and spatial resolution measurements on glass-ceramic and epoxy-composite X-ray storage phosphors. We find that the optical extinction coefficient at the stimulation and emission wavelengths is dominated by scattering for all the samples studied. However, the extinction coefficient is at least an order of magnitude lower in ZBLAN:BaCl{sub 2}:Eu{sup 2+} glass-ceramics when compared with the epoxy/BaCl{sub 2}:Eu{sup 2+} composites. Significantly reduced scattering is found in a epoxy/KBr:Eu{sup 2+} composite due to the better match between the refractive indices of the epoxy and crystallite. We show that the spatial resolution using a confocal microscope readout in a ZBLAN:BaCl{sub 2}:Eu{sup 2+} glass-ceramic is below 10{mu}m and hence this glass-ceramic has potential applications in high resolution radiation imaging.

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

    Science.gov (United States)

    Mcdanels, D. L.; Serafini, T. T.; Dicarlo, J. A.

    1986-01-01

    Advanced aircraft engine research within NASA Lewis is being focused 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.

  12. Structure recognition from high resolution images of ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela; Perciano, Talita; Krishnan, Harinarayan; Loring, Burlen; Bale, Hrishikesh; Parkinson, Dilworth; Sethian, James

    2015-01-05

    Fibers provide exceptional strength-to-weight ratio capabilities when woven into ceramic composites, transforming them into materials with exceptional resistance to high temperature, and high strength combined with improved fracture toughness. Microcracks are inevitable when the material is under strain, which can be imaged using synchrotron X-ray computed micro-tomography (mu-CT) for assessment of material mechanical toughness variation. An important part of this analysis is to recognize fibrillar features. This paper presents algorithms for detecting and quantifying composite cracks and fiber breaks from high-resolution image stacks. First, we propose recognition algorithms to identify the different structures of the composite, including matrix cracks and fibers breaks. Second, we introduce our package F3D for fast filtering of large 3D imagery, implemented in OpenCL to take advantage of graphic cards. Results show that our algorithms automatically identify micro-damage and that the GPU-based implementation introduced here takes minutes, being 17x faster than similar tools on a typical image file.

  13. Bone response to three different chemical compositions of fluorcanasite glass-ceramic.

    Science.gov (United States)

    da Rocha Barros, Valdemar Mallet; Liporaci, Jorge Luiz J; Rosa, Adalberto L; Junqueira, Marcela Caffarena; de Oliveira, Paulo Tambasco; Johnson, Anthony; van Noort, Richard

    2007-11-01

    The aim of this study was to evaluate the bone response to three fluorcanasite glass-ceramic compositions with different solubilities (K3, K5, and K8) after implantation in a femur rabbit model. Fluorcanasite glass-ceramic rods were implanted bilaterally in the mid-shafts rabbit femurs. Implants were harvested at 8 and 12 weeks and prepared for histological and histomorphometric analyses at the light microscope level. Bioglass 45S5 rods were used as a control material. At 8 weeks, all fluorcanasite glass-ceramics were entirely surrounded by a nonmineralized connective tissue. At 12 weeks, reduced areas of bone tissue were observed in the cortical area in direct contact with the K3 and K5 fluorcanasite glass-ceramics compared to Bioglass 45S5, whereas no bone tissue was observed in direct contact with the K8 surface. Bone-to-implant contact in the cortical area was affected by the material chemical composition and ranked as follows: Bioglass 45S5>K3>K5>K8 (p=0.001). In the bone marrow, a layer of fibrous connective tissue formed in direct contact with the fluorcanasite glass-ceramics and Bioglass 45S5, and only rarely exhibited contact osteogenesis. All the fluorcanasite glass-ceramics appeared to degrade in the biological environment. The solubility ratio did not alter significantly the biological reply of the fluorcanasite glass-ceramics in vivo. Further modifications of the chemical composition of the fluorcanasite glass-ceramic are required to increase the stability of the material in vivo.

  14. Advanced Ceramic Matrix Composites with Multifunctional and Hybrid Structures

    Science.gov (United States)

    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 (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.

  15. Analysis of crack initiation in the vicinity of an interface in brittle materials. Applications to ceramic matrix composites and nuclear fuels; Analyse de la fissuration au voisinage d'une interface dans les materiaux fragiles. Applications aux composites a matrice ceramique et aux combustibles nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Poitou, B

    2007-11-15

    In this study, criterions are proposed to describe crack initiation in the vicinity of an interface in brittle bi-materials. The purpose is to provide a guide for the elaboration of ceramic multi-layer structures being able to develop damage tolerance by promoting crack deflection along interfaces. Several cracking mechanisms are analyzed, like the competition between the deflection of a primary crack along the interface or its penetration in the second layer. This work is first completed in a general case and is then used to describe the crack deviation at the interface in ceramic matrix composites and nuclear fuels. In this last part, experimental tests are carried out to determine the material fracture properties needed to the deflection criteria. An optimization of the fuel coating can be proposed in order to increase its toughness. (author)

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

    Science.gov (United States)

    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.

  17. Glass matrix composite material prepared with waste foundry sand

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhao-shu; XIA Ju-pei; ZHU Xiao-qin; LIU Fan; HE Mao-yun

    2006-01-01

    The technology of glass matrix of the composite material manufactured through a sintering process and using waste foundry sand and waste glass as the main raw materials was studied. The effects of technological factors on the performance of this material were studied. The results showed that this composite material is formed with glass as matrix, core particulate as strengthening material, it has the performance of glass and ceramics, and could be used to substitute for stone.

  18. The effect of filler on the temperature coefficient of the relative permittivity of PTFE/ceramic composites

    Science.gov (United States)

    Rajesh, S.; Murali, K. P.; Jantunen, H.; Ratheesh, R.

    2011-11-01

    High permittivity and low-loss ceramic fillers have been prepared by means of the solid state ceramic route. Ceramic-filled composites were prepared by the Sigma Mixing, Extrusion, Calendering, which was followed by the Hot pressing (SMECH) process. The microwave dielectric properties of the composites were studied using X-band waveguide cavity perturbation technique. The temperature coefficient of the relative permittivity of the composites was investigated in the 0-100 °C temperature range using a hot and cold chamber coupled with an impedance analyzer. The temperature coefficient of the relative permittivity of the composites showed strong dependence on the temperature coefficient of the relative permittivity of the filler material. In the present study, a high-permittivity polymer/ceramic composite, having τεr ∼63 ppm/K, has been realized. This composite is suitable for outdoor wireless applications.

  19. Marginal Adaptation of Indirect Composite, Glass-Ceramic Inlays and Direct Composite: An In Vitro Evaluation

    Directory of Open Access Journals (Sweden)

    F. Mahboub

    2010-06-01

    Full Text Available Objective: This experimental in vitro study compared marginal adaptation of indirect composite, glass-ceramic inlays and direct composite.Materials and Methods: Seventy-five recently extracted human molars were randomly divided into three groups (n=25 and mesio-occluso-distal cavities with the same dimensions were prepared in the teeth. Indirect composite and glass-ceramic inlays were fabricatedfollowing manufacturer's instructions and the marginal gap was measured by a stereomicroscope at magnification 40× before cementation. After cementation of inlays and restoring the third group by direct composite, all the specimens were thermocycled and the marginal gaps were measured exactly as previously described. Repeated measure ANOVA and post-hoc Tukey test were used for pairwise comparison of occlusal, proximal, and gingival marginal gaps in each group. One-way ANOVA and post-hoc Tukey test wereused for comparison of mean marginal gap in the three groups and for comparison of marginal gap before and after cementation in inlays, paired T-test was used.Results: The marginal gap of direct composite (19.96 μm was significantly lower than that of indirect composite inlay (48.47 μm, which in itself was significantly lower than that of glass-ceramic inlay (60.96 μm. In all the restorations, marginal gap in the gingival margin was significantly higher than occlusal and proximal margins. The marginal gap of inlays did not change after cementation and thermocycling.Conclusion: This study indicated that the marginal gaps of the evaluated restorations are less than 100 μm, which is clinically acceptable.

  20. Continuous fiber ceramic composites for energy related applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-04-07

    The US Department of Energy has established the Continuous Fiber Ceramic Composites (CFCC) program to develop technology for the manufacture of CFCC`s for use in industrial applications where a reduction in energy usage or emissions could be realized. As part of this program, the Dow Chemical Company explored the manufacture of a fiber reinforced/self reinforced silicon nitride for use in industrial chemical processing. In Dow`s program, CFCC manufacturing technology was developed around traditional, cost effective, tape casting routes. Formulations were developed and coupled with unique processing procedures which enabled the manufacture of tubular green laminates of the dimension needed for the application. An evaluation of the effect of various fibers and fiber coatings on the properties of a fiber reinforced composites was also conducted. Results indicated that fiber coatings could provide composites exhibiting non-catastrophic failure and substantially improved toughness. However, an evaluation of these materials in industrial process environments showed that the material system chosen by Dow did not provide the required performance improvements to make replacement of current metallic components with CFCC components economically viable.

  1. Probabilistic Failure Analysis for Wound Composite Ceramic Cladding Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Lara-Curzio, Edgar [ORNL

    2013-01-01

    Advanced ceramic matrix composites based on silicon carbide (SiC) are being considered as candidate material systems for nuclear fuel cladding in light water reactors. The SiC composite structure is considered due to its assumed exceptional performance under accident scenarios, where its excellent high-temperature strength and slow reaction kinetics with steam and associated mitigated hydrogen production are desirable. The specific structures of interest consist of a monolithic SiC cylinder surrounded by interphase-coated SiC woven fibers in a tubular form and infiltrated with SiC. Additional SiC coatings on the outermost surface of the assembly are also being considered to prevent hydrothermal corrosion of the fibrous structure. The inner monolithic cylinder is expected to provide a hermetic seal to contain fission products under normal conditions. While this approach offers the promise of higher burn-up rates and safer behavior in the case of LOCA events, the reliability of such structures must be demonstrated in advance. Therefore, a probability failure analysis study was performed of such monolithic-composite hybrid structures to determine the feasibility of these design concepts. This analysis will be used to predict the future performance of candidate systems in an effort to determine the feasibility of these design concepts and to make future recommendations regarding materials selection.

  2. A ceramic matrix composite thermal protection system for hypersonic vehicles

    Science.gov (United States)

    Riccitiello, Salvatore R.; Love, Wendell L.; Pitts, William C.

    1993-01-01

    The next generation of hypersonic vehicles (NASP, SSTO) that require reusable thermal protection systems will experience acreage surface temperatures in excess of 1100 C. More important, they will experience a more severe physical environment than the Space Shuttle due to non-pristine launching and landing conditions. As a result, maintenance, inspection, and replacement factors must be more thoroughly incorporated into the design of the TPS. To meet these requirements, an advanced thermal protection system was conceived, designated 'TOPHAT'. This system consists of a toughened outer ceramic matrix composite (CMC) attached to a rigid reusable surface insulator (RSI) which is directly bonded to the surface. The objective of this effort was to evaluate this concept in an aeroconvective environment, to determine the effect of impacts to the CMC material, and to compare the results with existing thermal protection systems.

  3. Composite materials for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.H.; Henager, C.H. Jr.; Hollenberg, G.W.

    1991-10-01

    Ceramic matrix composites, CMCs, are being considered for advanced first-wall and blanket structural applications because of their high-temperature properties, low neutron activation, low density and low coefficient of expansion coupled with good thermal conductivity and corrosion behavior. This paper presents a review and analysis of the hermetic, thermal conductivity, corrosion, crack growth and radiation damage properties of CMCs. It was concluded that the leak rates of a gaseous coolant into the plasma chamber or tritium out of the blanket could exceed design criteria if matrix microcracking causes existing porosity to become interconnected. Thermal conductivities of unirradiated SiC/SiC and C/SiC materials are about 1/2 to 2/3 that of Type 316 SS whereas the thermal conductivity for C/C composites is seven times larger. The thermal stress figure-of-merit value for CMCs exceeds that of Type 316 SS for a single thermal cycle. SiC/SiC composites are very resistant to corrosion and are expected to be compatible with He or Li coolants if the O{sub 2} concentrations are maintained at the appropriate levels. CMCs exhibit subcritical crack growth at elevated temperatures and the crack velocity is a function of the corrosion conditions. The radiation stability of CMCs will depend on the stability of the fiber, microcracking of the matrix, and the effects of gaseous transmutation products on properties. 23 refs., 14 figs., 1 tab.

  4. A novel calcium phosphate ceramic-magnetic nanoparticle composite as a potential bone substitute.

    Science.gov (United States)

    Wu, Yao; Jiang, Wen; Wen, Xiantao; He, Bin; Zeng, Xiaobo; Wang, Gang; Gu, Zhongwei

    2010-02-01

    A magnetic field has been applied to accelerate bone healing for a long time. In this study, in order to combine the bone repair capability of calcium phosphate (CaP) ceramics with the magnetic field, a novel CaP ceramic-magnetic nanoparticle (CaP-MNP) composite was fabricated through integrating the superparamagnetic nanoparticles into the CaP ceramics. Two kinds of CaP ceramics were chosen: hydroxyapatite (HA) and HA/tricalcium phosphate (65/35, HT). The samples were cultured with Ros17/2.8 and MG63 cells respectively in vitro to evaluate the cell proliferation and differentiation via MTT and alkaline phosphatase activity tests. In order to find the influence of the magnetic materials on the expression of the bone morphological protein (BMP), the samples composited with BMP-2 were implanted subcutaneously in the fasciae of rat back muscles for 30 days. Compared with ordinary CaP ceramics, the results indicated that the CaP-MNP composite had good biocompatibility and was able to promote cell proliferation and differentiation significantly. The in vivo test showed that the expression of BMP-2 would be accelerated by HT composited with MNPs, and new bone-like tissue formation could be observed. Accordingly, it might be expected that this CaP-MNP composite could become a potential bone substitute or bone tissue engineering scaffold.

  5. Prepreg and Melt Infiltration Technology Developed for Affordable, Robust Manufacturing of Ceramic Matrix Composites

    Science.gov (United States)

    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.

  6. Porous biomorphic silicon carbide ceramics coated with hydroxyapatite as prospective materials for bone implants.

    Science.gov (United States)

    Gryshkov, Oleksandr; Klyui, Nickolai I; Temchenko, Volodymyr P; Kyselov, Vitalii S; Chatterjee, Anamika; Belyaev, Alexander E; Lauterboeck, Lothar; Iarmolenko, Dmytro; Glasmacher, Birgit

    2016-11-01

    Porous and cytocompatible silicon carbide (SiC) ceramics derived from wood precursors and coated with bioactive hydroxyapatite (HA) and HA-zirconium dioxide (HA/ZrO2) composite are materials with promising application in engineering of bone implants due to their excellent mechanical and structural properties. Biomorphic SiC ceramics have been synthesized from wood (Hornbeam, Sapele, Tilia and Pear) using a forced impregnation method. The SiC ceramics have been coated with bioactive HA and HA/ZrO2 using effective gas detonation deposition approach (GDD). The surface morphology and cytotoxicity of SiC ceramics as well as phase composition and crystallinity of deposited coatings were analyzed. It has been shown that the porosity and pore size of SiC ceramics depend on initial wood source. The XRD and FTIR studies revealed the preservation of crystal structure and phase composition of in the HA coating, while addition of ZrO2 to the initial HA powder resulted in significant decomposition of the final HA/ZrO2 coating and formation of other calcium phosphate phases. In turn, NIH 3T3 cells cultured in medium exposed to coated and uncoated SiC ceramics showed high re-cultivation efficiency as well as metabolic activity. The recultivation efficiency of cells was the highest for HA-coated ceramics, whereas HA/ZrO2 coating improved the recultivation efficiency of cells as compared to uncoated SiC ceramics. The GDD method allowed generating homogeneous HA coatings with no change in calcium to phosphorus ratio. In summary, porous and cytocompatible bio-SiC ceramics with bioactive coatings show a great promise in construction of light, robust, inexpensive and patient-specific bone implants for clinical application.

  7. Bonding of ceramic insert to a laboratory particle filler composite.

    Science.gov (United States)

    Kienanen, Pietari; Alander, Pasi; Lassila, Lippo V J; Vallittu, Pekka K

    2005-10-01

    The push-out bond strength of cylindrical ceramic inserts (CI) to particulate filler resin composite (VC) was evaluated in this study. Various surface treatments to improve the adhesion of CI to resin composite were tested. Additionally, the effect of fiber-reinforced composite (FRC) laminate encapsulation around CI was tested. Feldspathic porcelain CI with a diameter of 3.1 mm was bonded to VC. Adhesive resin was used for bonding. In group 1, no surface treatment of CI was done. In group 2, CI was encapsulated with a thin layer of woven glass FRC. In group 3, the surface of the CI was tribochemically silica coated and silanized. In group 4, the surface of the CI was grit-blasted with 50 microm aluminum oxide and etched with hydrofluoric acid. In group 5, the grit-blasted CI was encapsulated with a layer of FRC. The specimens (n = 6/group) were either dry stored or thermocycled in water (6000 x 5-55 degrees C). The push-out test was carried out with a universal material testing machine. The highest push-out strength was achieved in group 5 (20.4 MPa) and the lowest in group 2 (11.5 MPa). ANOVA revealed that both surface treatment and storage condition had a significant effect on push-out strength (p < 0.05). We conclude that the additional glass FRC encapsulation can be used to increase the bond strength of insert to composite.

  8. Design Concepts for Cooled Ceramic Composite Turbine Vane

    Science.gov (United States)

    Boyle, Robert J.; Parikh, Ankur H.; Nagpal, VInod K.

    2015-01-01

    The objective of this work was to develop design concepts for a cooled ceramic vane to be used in the first stage of the High Pressure Turbine(HPT). To insure that the design concepts were relevant to the gas turbine industry needs, Honeywell International Inc. was subcontracted to provide technical guidance for this work. The work performed under this contract can be divided into three broad categories. The first was an analysis of the cycle benefits arising from the higher temperature capability of Ceramic Matrix Composite(CMC) compared with conventional metallic vane materials. The second category was a series of structural analyses for variations in the internal configuration of first stage vane for the High Pressure Turbine(HPT) of a CF6 class commercial airline engine. The third category was analysis for a radial cooled turbine vanes for use in turboshaft engine applications. The size, shape and internal configuration of the turboshaft engine vanes were selected to investigate a cooling concept appropriate to small CMC vanes.

  9. Ceramic matrix composites based on Mg-PSZ with Cr-Ni-steel-additions with improved thermo-mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, C., E-mail: claudia.wenzel@ikgb.tu-freiberg.de [Institute of Ceramic, Glass and Construction Materials, Technische Universitaet Bergakademie Freiberg, Agricolastr. 17, D-09599 Freiberg (Germany); Aneziris, C.G., E-mail: aneziris@ikgb.tu-freiberg.de [Institute of Ceramic, Glass and Construction Materials, Technische Universitaet Bergakademie Freiberg, Agricolastr. 17, D-09599 Freiberg (Germany)

    2011-01-15

    The application of ceramic materials is limited due to their inherent brittleness. In the past years attempts have been made to improve the fracture toughness of structural ceramics by adding a secondary phase. In the present paper the influence of metastable austenitic TRIP-steel powder on the thermo-mechanical properties of magnesia partially stabilised zirconia has been investigated. Ceramic matrix composites have been prepared using slip casting technology. The sintering was performed in different argon atmospheres. The incorporation of the metastable metallic phase led to the successful generation of composite materials with advanced mechanical properties, especially after thermal shock attack.

  10. Thermomechanical and Environmental Durability of Environmental Barrier Coated Ceramic Matrix Composites Under Thermal Gradients

    Science.gov (United States)

    Zhu, Dongming; Bhatt, Ramakrishna T.; Harder, Bryan

    2016-01-01

    This paper presents the developments of thermo-mechanical testing approaches and durability performance of environmental barrier coatings (EBCs) and EBC coated SiCSiC ceramic matrix composites (CMCs). Critical testing aspects of the CMCs will be described, including state of the art instrumentations such as temperature, thermal gradient, and full field strain measurements; materials thermal conductivity evolutions and thermal stress resistance; NDE methods; thermo-mechanical stress and environment interactions associated damage accumulations. Examples are also given for testing ceramic matrix composite sub-elements and small airfoils to help better understand the critical and complex CMC and EBC properties in engine relevant testing environments.

  11. Thixoforming of SiC ceramic matrix composites in pseudo-semi-solid state

    Institute of Scientific and Technical Information of China (English)

    CHENG Yuan-sheng; LUO Shou-jing; DU Zhi-ming

    2005-01-01

    A new forming process, ceramic matrix composites thixoforming in pseudo-semi-solid state, was proposed based on powder metallurgy technology combined with the semi-solid metal forming process. The satellite angle-frames were prepared by this technology with Alp and SiCp materials mixed with different volume fractions. It is proved that it is feasible for the forming of the ceramic matrix composites by this technology through metallographic analyses and tensile tests. The results also show that the microstructures of samples are homogeneous and they have high hardness and certain plasticity.

  12. Characterization of silicon-silicon carbide ceramic derived from carbon-carbon silicon carbide composites

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Vijay K. [Indian Institute of Technology, Varanasi (India). Dept. of Mechanical Engineering; Krenkel, Walter [Univ. of Bayreuth (Germany). Dept. of Ceramic Materials Engineering

    2013-04-15

    The main objective of the present work is to process porous silicon - silicon carbide (Si - SiC) ceramic by the oxidation of carboncarbon silicon carbide (C/C - SiC) composites. Phase studies are performed on the oxidized porous composite to examine the changes due to the high temperature oxidation. Further, various characterization techniques are performed on Si- SiC ceramics in order to study the material's microstructure. The effects of various parameters such as fiber alignment (twill weave and short/chopped fiber) and phenolic resin type (resol and novolak) are characterized.

  13. Ceramic matrix composite applications in advanced liquid fuel rocket engine turbomachinery

    Science.gov (United States)

    Brockmeyer, Jerry W.

    1992-01-01

    Fiber-reinforced ceramic matrix composites have been identified with properties suitable for near term applications. Conceptual design studies indicate the feasibility of applying C/SiC, and subelements were manufactured that verify selected fabrication features and key material properties. Tests and inspection of these subelements confirmed their capabilities.

  14. Effects of Temperature and Environment on Creep Behavior of an Oxide-Oxide Ceramic Matrix Composite

    Science.gov (United States)

    2007-03-01

    resistant ceramic matrix composites by a precursor infiltration and pyrolysis method,” Materials Science and Engineering, A195:145-150 (1995). 33...the B-52 and F-16 airframes. He also spent a year as the Air Force Tire Engineer. In August 2005 he began graduate school work at the Air Force

  15. Indirect composite resin materials for posterior applications.

    Science.gov (United States)

    Shellard, E; Duke, E S

    1999-12-01

    Indirect composite resin restorations were introduced a number of years ago as possible alternatives to traditional metallic or ceramic-based indirect restorations. However, the earlier formulations did not provide evidence of improvement in mechanical and physical properties over chairside-placed direct composite resin materials. Because they required more tooth structure removal than direct restorations, their use became unpopular and was abandoned by most clinicians. Over the past few years, a new class of composite resin indirect materials has surfaced in the profession. Various technologies have been suggested as reinforcement mechanisms. Fibers, matrix modifications, and an assortment of innovations have been proposed for enhancing indirect composite resin restorations. Applications are from inlay restorations all the way to multi-unit fixed prostheses. This manuscript summarizes some of the progress made in this area. When available, data is presented to provide clinicians with guidelines and indications for the use of these materials.

  16. Ceramic compositional analysis in archaeological perspective

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, R.L.; Rands, R.L.; Holley, G.R.

    1980-01-01

    The primary significance of compositional analysis in archaeology lies on the spatial dimension, in distinguishing products made by locally or regionally-based groups. If compositional analysis is to be carried beyond the descriptive recording of similarities and differences, the resource procurement zone (and its geographical relationship to inferred places of manufacture) is a basic operational concept (Rands and Bishop 1980). A zonal concept is clearly indicated in the case of pottery, which frequently is derived from raw materials, clay and temper, that do not necessarily coincide in their place of procurement. Moreover, depending on geomorphological and geochemical variables, these materials may show considerable homogeneity over a fairly extended area. On the other hand, unless there is strong, selective patterning in the exploitation of resources, great heterogeneity within a restricted region may result in fragmented procurement zones that are difficult to equate with the products of specific manufacturing centers. Under favorable circumstances, however, it appears that methods of compositional analysis are approaching the point at which microzones of limited geographical extent can be recognized and assigned heuristically useful boundaries.

  17. Microanalytical investigation of fibre-reinforced ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Meier, B.; Grathwohl, G.

    1989-03-01

    Microanalytical investigations have been made on samples of ceramic fibres (SiC fibres, (Nicalon) C fibre coated with TiN) and fibre-reinforced ceramics (SiC-and glass-matrices). High resolution Auger electron spectroscopy (HRAES), electron probe microanalysis (EPMA) and scanning electron microscopy were employed for these examinations. Analysis was best performed with HRAES on account of its lateral and depth resolution. Some of the problems involved in this technique are discussed e.g. electron beam effects. AES depth profiles of ceramic fibres are reported and compared with the surface analysis of fibres in the composites after being broken in situ.

  18. Advanced Measurements of Silicon Carbide Ceramic Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    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

  19. Large Area Roller Embossing of Multilayered Ceramic Green Composites

    CERN Document Server

    Shan, X; Shi, C W P; Tay, C K; Lu, C W

    2008-01-01

    In this paper, we will report our achievements in developing large area patterning of multilayered ceramic green composites using roller embossing. The aim of our research is to pattern large area ceramic green composites using a modified roller laminating apparatus, which is compatible with screen printing machines, for integration of embossing and screen printing. The instrumentation of our roller embossing apparatus, as shown in Figure1, consists of roller 1 and rollers 2. Roller 1 is heated up to the desired embossing temperature ; roller 2 is, however, kept at room temperature. The mould is a nickel template manufactured by plating nickel-based micro patterns (height : 50 $\\mu$m) on a nickel film (thickness : 70 $\\mu$m) ; the substrate for the roller embossing is a multilayered Heraeus Heralock HL 2000 ceramic green composite. Comparing with the conventional simultaneous embossing, the advantages of roller embossing include : (1) low embossing force ; (2) easiness of demoulding ; (3) localized area in co...

  20. Fatigue and frictional heating in ceramic matrix composites

    DEFF Research Database (Denmark)

    Jacobsen, T.K.; Sørensen, B.F.; Brøndsted, P.

    1997-01-01

    This paper describes an experimental technique for monitoring the damage evolution in ceramic matrix composites during cyclic testing. The damage is related to heat dissipation, which may be measured as radiated heat from the surface of the test specimen. In the present experimental set-up an iso......This paper describes an experimental technique for monitoring the damage evolution in ceramic matrix composites during cyclic testing. The damage is related to heat dissipation, which may be measured as radiated heat from the surface of the test specimen. In the present experimental set...... with a high spatial and temperature resolution and changes in the heat dissipation can be measured almost instantaneously. The technique has been tested on uni-directional ceramic matrix composites. Experimental results are shown and the possibilities and the limitations of the technique are discussed....

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

    Science.gov (United States)

    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.

  2. Alumina matrix ceramic-nickel composites formed by centrifugal slip casting

    Directory of Open Access Journals (Sweden)

    Justyna Zygmuntowicz

    2015-12-01

    Full Text Available The paper is focused on the possibility of fabricating the alumina matrix ceramic-nickel composites with gradient concentration of metal particles. Centrifugal slip casting method was chosen for the composite fabrication. This method allows fabrication of the graded distribution of nickel particles in the hollow cylinder composites. The horizontal rotation axis was applied. The samples were characterized by XRD, SEM and quantitative description of the microstructure. The macroscopic as well as SEM observations of the prepared composites confirmed the gradient concentration of Ni particles in the composite materials. The application of the centrifugal slip casting method allows for the graded distribution of metal particles in the samples.

  3. Stochastic Virtual Tests for High-Temperature Ceramic Matrix Composites

    Science.gov (United States)

    Cox, Brian N.; Bale, Hrishikesh A.; Begley, Matthew; Blacklock, Matthew; Do, Bao-Chan; Fast, Tony; Naderi, Mehdi; Novak, Mark; Rajan, Varun P.; Rinaldi, Renaud G.; Ritchie, Robert O.; Rossol, Michael N.; Shaw, John H.; Sudre, Olivier; Yang, Qingda; Zok, Frank W.; Marshall, David B.

    2014-07-01

    We review the development of virtual tests for high-temperature ceramic matrix composites with textile reinforcement. Success hinges on understanding the relationship between the microstructure of continuous-fiber composites, including its stochastic variability, and the evolution of damage events leading to failure. The virtual tests combine advanced experiments and theories to address physical, mathematical, and engineering aspects of material definition and failure prediction. Key new experiments include surface image correlation methods and synchrotron-based, micrometer-resolution 3D imaging, both executed at temperatures exceeding 1,500°C. Computational methods include new probabilistic algorithms for generating stochastic virtual specimens, as well as a new augmented finite element method that deals efficiently with arbitrary systems of crack initiation, bifurcation, and coalescence in heterogeneous materials. Conceptual advances include the use of topology to characterize stochastic microstructures. We discuss the challenge of predicting the probability of an extreme failure event in a computationally tractable manner while retaining the necessary physical detail.

  4. Magnesium Effect to the Hardness of Al2O3/Al Ceramic Matrix Composites

    Directory of Open Access Journals (Sweden)

    Eddy S. Siradj

    2009-04-01

    Full Text Available Composite is an alternative materialwhich has satisfying properties and can be accommodated for certain applications. Ceramic Matrix Composites (CMCsis one of the composite types that are very interesting in terms of high temperature applications material. In this paper,we investigate the effects of Mg addition on the hardness of Al2O3 Ceramic Matrix Composites which was produced bydirected metal oxidation (Dimox method. The CMCs material is made by placing Al ingot under mixture alumina andpercentage of Mg 5, 8, 10, and 12% wt. The processing temperature was 1100°C for 24 hours followed by cooling toroom temperature in the furnace. The results show that increasing of infiltration, the hardness increased to 1221 VHNmaximum at 8% wt Mg and then decrease again as the increment amount of Mg.

  5. Mechanochemically synthesized kalsilite based bioactive glass-ceramic composite for dental vaneering

    Science.gov (United States)

    Kumar, Pattem Hemanth; Singh, Vinay Kumar; Kumar, Pradeep

    2015-08-01

    Kalsilite glass-ceramic composites have been prepared by a mechanochemical synthesis process for dental veneering application. The aim of the present study is to prepare bioactive kalsilite composite material for application in tissue attachment and sealing of the marginal gap between fixed prosthesis and tooth. Mechanochemical synthesis is used for the preparation of microfine kalsilite glass-ceramic. Low temperature frit and bioglass have been prepared using the traditional quench method. Thermal, microstructural and bioactive properties of the composite material have been examined. The feasibility of the kalsilite to be coated on the base commercial opaque as well as the bioactive behavior of the coated specimen has been confirmed. This study indicates that the prepared kalsilite-based composites show similar structural, morphological and bioactive behavior to that of commercial VITA VMK95 Dentin 1M2.

  6. Micromechanics of Composite Materials

    CERN Document Server

    Dvorak, George

    2013-01-01

    This book presents a broad exposition of analytical and numerical methods for modeling composite materials, laminates, polycrystals and other heterogeneous solids, with emphasis on connections between material properties and responses on several length scales, ranging from the nano and microscales to the macroscale. Many new results and methods developed by the author are incorporated into a rich fabric of the subject, which has been explored by several researchers over the last 40 years.   The first  part of the book reviews anisotropic elasticity theory, and then it describes the frequently used procedures and theorems for bounding and estimating overall properties, local fields and energy changes in elastic inhomogeneities, heterogeneous media, fiber composites and functionally graded materials.  Those are caused by mechanical loads and by phase eigenstrains, such as thermal, transformation and inelastic strains, and also by cavities and cracks.    Worked examples show that the eigendeformations may...

  7. Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix and Polymer Matrix Composite Structures

    Science.gov (United States)

    Nemeth, Noel N.; Bednarcyk, Brett A.; Pineda, Evan J.; Walton, Owen J.; Arnold, Steven M.

    2016-01-01

    Stochastic-based, discrete-event progressive damage simulations of ceramic-matrix composite and polymer matrix composite material structures have been enabled through the development of a unique multiscale modeling tool. This effort involves coupling three independently developed software programs: (1) the Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC), (2) the Ceramics Analysis and Reliability Evaluation of Structures Life Prediction Program (CARES/ Life), and (3) the Abaqus finite element analysis (FEA) program. MAC/GMC contributes multiscale modeling capabilities and micromechanics relations to determine stresses and deformations at the microscale of the composite material repeating unit cell (RUC). CARES/Life contributes statistical multiaxial failure criteria that can be applied to the individual brittle-material constituents of the RUC. Abaqus is used at the global scale to model the overall composite structure. An Abaqus user-defined material (UMAT) interface, referred to here as "FEAMAC/CARES," was developed that enables MAC/GMC and CARES/Life to operate seamlessly with the Abaqus FEA code. For each FEAMAC/CARES simulation trial, the stochastic nature of brittle material strength results in random, discrete damage events, which incrementally progress and lead to ultimate structural failure. This report describes the FEAMAC/CARES methodology and discusses examples that illustrate the performance of the tool. A comprehensive example problem, simulating the progressive damage of laminated ceramic matrix composites under various off-axis loading conditions and including a double notched tensile specimen geometry, is described in a separate report.

  8. Preliminary study of chemical compositional data from Amazon ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Toyota, Rosimeiri G.; Munita, Casimiro S.; Luz, Fabio A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: rosimeiritoy@yahoo.com.br; Neves, Eduardo G. [Museu de Arqueologia e Etnolgia, Sao Paulo, SP (Brazil)]. E-mail: egneves@usp.br; Oliveira, Paulo M.S. [Sao Paulo Univ., SP (Brazil). Escola Politecnica. Inst. de Matematica e Estatistica]. E-mail: poliver@usp.br

    2005-07-01

    Eighty seven ceramic samples from Acutuba, Lago Grande and Osvaldo archaeological sites located in the confluence of the rivers Negro and Solimoes were submitted to chemical analysis using instrumental neutron activation analysis to determine As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Rb, Na, Nd, Sb, Sc, Sm, Ta, Tb, Th, Yb, Zn, and U. The database were studied using the Mahalanobis distance, and discriminant analysis. The results showed that the ceramics of each site differ from each other in chemical composition and that they form three different groups. Chemical classification of the ceramics suggests that vessels were made locally, as only ceramics from the same area show homogeneity of data. (author)

  9. Monitoring Damage Accumulation in Ceramic Matrix Composites Using Electrical Resistivity

    Science.gov (United States)

    Smith, Craig E.; Morscher, Gregory N.; Xia, Zhenhai H.

    2008-01-01

    The electric resistance of woven SiC fiber reinforced SiC matrix composites were measured under tensile loading conditions. The results show that the electrical resistance is closely related to damage and that real-time information about the damage state can be obtained through monitoring of the resistance. Such self-sensing capability provides the possibility of on-board/in-situ damage detection and accurate life prediction for high-temperature ceramic matrix composites. Woven silicon carbide fiber-reinforced silicon carbide (SiC/SiC) ceramic matrix composites (CMC) possess unique properties such as high thermal conductivity, excellent creep resistance, improved toughness, and good environmental stability (oxidation resistance), making them particularly suitable for hot structure applications. In specific, CMCs could be applied to hot section components of gas turbines [1], aerojet engines [2], thermal protection systems [3], and hot control surfaces [4]. The benefits of implementing these materials include reduced cooling air requirements, lower weight, simpler component design, longer service life, and higher thrust [5]. It has been identified in NASA High Speed Research (HSR) program that the SiC/SiC CMC has the most promise for high temperature, high oxidation applications [6]. One of the critical issues in the successful application of CMCs is on-board or insitu assessment of the damage state and an accurate prediction of the remaining service life of a particular component. This is of great concern, since most CMC components envisioned for aerospace applications will be exposed to harsh environments and play a key role in the vehicle s safety. On-line health monitoring can enable prediction of remaining life; thus resulting in improved safety and reliability of structural components. Monitoring can also allow for appropriate corrections to be made in real time, therefore leading to the prevention of catastrophic failures. Most conventional nondestructive

  10. Vapor-phase fabrication and properties of continuous-filament ceramic composites.

    Science.gov (United States)

    Besmann, T M; Sheldon, B W; Lowden, R A; Stinton, D P

    1991-09-06

    The continuous-filament ceramic composite is becoming recognized as necessary for new, high-temperature structural applications. Yet because of the susceptibility of the filaments to damage from traditional methods for the preparation of ceramics, vapor-phase infiltration has become the fabrication method of choice. The chemical vapor infiltration methods for producing these composites are now being studied in earnest, with the complexity of filament weaves and deposition chemistry being merged with standard heat and mass-transport relationships. Two of the most influential effects on the mechanical properties of these materials are the adhesion and frictional force between the fibers and the matrix, which can be controlled by a tailored interface coating. A variety of materials are available for producing these composites including carbide, nitride, boride, and oxide filaments and matrices. Silicon carbide-based materials are by far the most advanced and are already being used in aerospace applications.

  11. Mechanical Spectroscopy of Nanostructured Composite Materials

    Energy Technology Data Exchange (ETDEWEB)

    Mari, Daniele; Schaller, Robert; Mazaheri, Mehdi, E-mail: daniele.mari@epfl.ch [Ecole Polytechnique Federale de Lausanne, Laboratoire de Physique de la Matiere Complexe, Groupe de Spectroscopie Mecanique, CH-1015 Lausanne (Switzerland)

    2011-07-06

    The thermo-mechanical behavior of different nano-structured composite materials, which were processed within the SAPHIR European Integrated Project, has been characterized by mechanical spectroscopy. The obtained results show clearly that creep resistance of fine grain ceramics such as zirconia can be improved by carbon nano-tube (CNT) reinforcements. On the other hand the elastic modulus and the damping capacity of aluminum matrix composites were increased by SiC nano-particle additions. It has also been observed that CNT additions are responsible for a better thermal stability of polymer such as ABS (Acrylonitrile-Butadiene-Styrene) used in automotive industry.

  12. Microwave Measurements of Ferrite Polymer Composite Materials

    Directory of Open Access Journals (Sweden)

    Rastislav Dosoudil

    2004-01-01

    Full Text Available The article focuses on the microwave measurements performed on the nickel-zinc sintered ferrite with the chemical formula Ni0.3Zn0.7Fe2O4 produced by the ceramic technique and composite materials based on this ferrite and a non-magnetic polymer (polyvinyl chloride matrix. The prepared composite samples had the same particle size distribution 0-250um but different ferrite particle concentrations between 23 vol% and 80 vol%. The apparatus for measurement of the signal proportional to the absolute value of scattering parameter S11 (reflexion coefficient is described and the dependence of measured reflected signal on a bias magnetic field has been studied. By means of experiments, the resonances to be connected with the geometry of microwave experimental set-up were distinguished from ferromagnetic resonance arising in ferrite particles of composite structure. The role of local interaction fields of ferrite particles in composite material has been discussed.

  13. Stain susceptibility of composite and ceramic CAD/CAM blocks versus direct resin composites with different resinous matrices.

    Science.gov (United States)

    Alharbi, Amal; Ardu, Stefano; Bortolotto, Tissiana; Krejci, Ivo

    2017-04-01

    To evaluate the stain susceptibility of CAD/CAM blocks and direct composite after long term exposure to various staining agents. 40 disk-shaped samples were fabricated from each of nine materials; six CAD/CAM (Vitablocs Mark II, Paradigm MZ100, Experimental Vita Hybrid Ceramic, Vita Enamic, Experimental Kerr and Lava Ultimate) and three direct composites (Filtek Supreme, Venus Diamond and Filtek Silorane). Samples were randomly divided into five groups (n = 8) according to different staining solutions (distilled water, tea, red wine, coffee and artificial saliva). Initial L*a*b* values were assessed using a calibrated digital spectrophotometer. Specimens were immersed in staining solutions and stored in an incubator at 37 °C for 120 days. L*a*b* values were assessed again and color change (∆E) was calculated as difference between recorded L*a*b* values. ANOVA, and Duncan test were used to identify differences between groups (α = 0.05). Significant differences in ∆E values were detected between materials (p = 0.000). Among all staining solutions, the highest ∆E value was observed with red wine. The new CAD/CAM blocks (Vita Enamic, Vita Hybrid Ceramic and Lava Ultimate) showed the highest resistance to staining compared to the MZ100 composite resin blocks. Filtek Silorane, a direct composite, showed high stain resistance values compared to CAD/CAM materials and other direct composites. Ceramic and composite CAD/CAM blocks had lower staining susceptibility than methacrylate based direct composite. Staining susceptibility of the new resin based CAD/CAM materials Vita Enamic and Lava Ultimate was comparable to feldspathic ceramic blocks (Vitablocs Mark II). Filtek Silorane showed promising results that were comparable to some CAD/CAM blocks.

  14. Multi-scale modeling of deformation and fracture of ceramic materials under dynamic loading

    Science.gov (United States)

    Skripnyak, Evgeniya; Skripnyak, Vladimir; Skripnyak, Vladimir; Vaganova, Irina; Skripnyak, Nataliya

    2013-06-01

    The multi-scale approach to dynamic analysis of deformation and fracture, taking place in structured condensed matter show a great promise in prediction of the mechanical response for new materials. In present work the results of two-level simulations on deformation and fracture mechanisms for brittle materials subjected to impulse and shock-wave loadings are demonstrated. The dynamic effects occurring in structured representative volumes of the ceramics and the processes relating to damage and fracture of the ceramic materials with porous structures, ceramic composites and nanocomposites were modeled using the SPH methods. The grain, phase and porous structures were simulated in an explicit form. The presence of dispersed inclusions, dislocation substructures, nano - and micro-voids at the lower structural level were taking into account in an implicit form. The two-level model allows taking into account different relaxation and fracturing characteristic times at the different structural levels. This approach suggest to describe the relaxation process at the higher structural level in terms of integrated effect of the lower level processes. It is found that clusters of nano-voids in ceramic materials are the centers of damage nucleation. The presence of the clusters of nano-voids in ceramic materials subjected to dynamic loadings results in decrease of the Hugoniot elastic limit value.

  15. NASA's Reusable Launch Vehicle Technologies: A Composite Materials Overview

    Science.gov (United States)

    Clinton, R. G., Jr.; Cook, Steve; Effinger, Mike; Smith, Dennis; Swint, Shayne

    1999-01-01

    A materials overview of the NASA's Earth-to-Orbit Space Transportation Program is presented. The topics discussed are: Earth-to-Orbit Goals and Challenges; Space Transportation Program Structure; Generations of Reusable Launch Vehicles; Space Transportation Derived Requirements; X 34 Demonstrator; Fastrac Engine System; Airframe Systems; Propulsion Systems; Cryotank Structures; Advanced Materials, Fabrication, Manufacturing, & Assembly; Hot and Cooled Airframe Structures; Ceramic Matrix Composites; Ultra-High Temp Polymer Matrix Composites; Metal Matrix Composites; and PMC Lines Ducts and Valves.

  16. Fly ash of mineral coal as ceramic tiles raw material.

    Science.gov (United States)

    Zimmer, A; Bergmann, C P

    2007-01-01

    The aim of this work was to evaluate the use of mineral coal fly ash as a raw material in the production of ceramic tiles. The samples of fly ash came from Capivari de Baixo, a city situated in the Brazilian Federal State of Santa Catarina. The fly ash and the raw materials were characterized regarding their physical chemical properties, and, based on these results; batches containing fly ash and typical raw materials for ceramic tiles were prepared. The fly ash content in the batches varied between 20 and 80 wt%. Specimens were molded using a uniaxial hydraulic press and were fired. All batches containing ash up to 60 wt% present adequate properties to be classified as several kinds of products in the ISO 13006 standard () regarding its different absorption groups (pressed). The results obtained indicate that fly ash, when mixed with traditional raw materials, has the necessary requirements to be used as a raw material for production of ceramic tiles.

  17. Sol-gel coatings as active barriers to protect ceramic reinforcement in aluminum matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Rams, J.; Urena, A.; Campo, M. [Departamento de Tecnologia Quimica, Ambiental y de los Materiales, ESCET, Universidad Rey Juan Carlos C/ Tulipan s/nMostoles 28933 Madrid (Spain)

    2004-02-01

    Silica obtained through a sol-gel process is used as a coating for ceramic reinforcements (SiC) in aluminium matrix composite materials. The interaction between molten aluminium and the coated particles during material casting can be controlled by means of the thermal treatment given to the coating. Wettability is increased because the coating reacts with molten aluminium, and the formation of the degrading aluminium carbide is inhibited. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  18. Ion sputtering erosion mechanisms of h-BN composite ceramics with textured microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Xiaoming, E-mail: dxm_hit@126.com [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Ding, Yongjie [School of Energy Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Jia, Dechang; Jing, Nan; Yang, Zhihua; He, Peigang; Tian, Zhuo; Wang, Shengjin; Wang, Yujin; Zhou, Yu [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Yu, Daren [School of Energy Science and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2014-11-15

    Highlights: • Textured h-BN ceramics were made by hot press sintering using mullite as additives. • Sintering pressures play important role on ions sputtering resistance properties. • Textured microstructures lead to various surface morphologies by ion sputtering. • Sputtering erosion mechanisms include B–N bonds breaking and BN layers delamination. - Abstract: Since the hexagonal boron nitride (h-BN) grain shows typical lamellar structures, textured materials can be obtained by arranging h-BN grains along one direction. In this work, textured h-BN composite ceramics with the c-axis orientation arranged along the pressure direction are manufactured by hot-press sintering using mullite as the sintering additive. The results show that sintering pressures not only play a major role in the density and the textured degrees of composite ceramics, but also influence Xe ion erosion resistance performances. After Xe ion sputtering, compositions of both h-BN and mullite stay stable, while the elemental compositions have changed due to the so-called “preferential sputtering”. Sputtered surfaces along different orientations show diverse morphologies attributed to the textured microstructures. The erosion mechanisms of h-BN grains during Xe ion sputtering are breaking of B–N bonds and delamination of BN layers. While the mass loss of composite ceramics is due to the erosion of h-BN grains and mullite coupled with partial detachment of h-BN grains from the surface.

  19. X-Ray Diffraction Phase Analyses for Granulated and Sintered Ceramic Materials

    Directory of Open Access Journals (Sweden)

    Suminar Pratapa

    2007-11-01

    Full Text Available One basic problematic aspect in x-ray diffraction phase analysis is microabsorption effect which may arise from the size of the crystallite phases. Complication of the problem may intensify in sintered ceramic materials where milling of the samples is not simple. We report the Rietveld x-ray diffraction phase analysis of MgO-α-Al2O3 powder mixtures with phase content ratio of 1:1 by weight and MgO-Y2O3 sintered ceramic composites with Y2O3 contents of 10%, 20% and 30% by weight. The mixtures were pre-sintered at 1000°C for 2 hours and then milled while the composites were sintered at 1550°C for 3 hours. The phase composition analysis was done using Rietica, a non-commercial Rietveld method-based software. Relative and absolute phase compositions were examined and results showed that there was a significant amount of phase composition bias resulted from the examination. For the powder mixture, milling can reduce microabsorption effect and hence the calculation bias. For the ceramic composite where milling is almost impossible, additional of Y2O3 caused smaller crystallite size of MgO, so that composition bias is smaller in composites with higher Y2O3 content. A mathematical model is proposed to provide more acceptable phase composition results.

  20. Composite definition features using the eastern ornament in ceramic tiles

    OpenAIRE

    2013-01-01

    This paper was asked a series of questions for the study of composition of the artistic shaping of ceramic tile with oriental ornaments and how to use in interior design. Particular attention is paid to individual elements of ornament and use them in areas such as kitchens, bathrooms, hookah area, cafe and more.

  1. Analysis of Damage in a Ceramic Matrix Composite

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Talreja, Ramesh

    1993-01-01

    Mechanisms of damage and the associated mechanical response are stud ied for a unidirectionally fiber-reinforced ceramic matrix composite subjected to uniaxial tensile loading parallel to fibers. A multi-stage development of damage is identified, and for each stage the governing mechanisms...

  2. Microstructure and properties of ceramics and composites joined by plastic deformation.

    Energy Technology Data Exchange (ETDEWEB)

    Goretta, K. C.; Singh, D.; Chen, N.; Gutierrez-Mora, F.; Lorenzo-Martin, M. de la, Cinta; Dominguez-Rodriguez, A.; Routbort, J. L.; Energy Systems; Univ. of Seville

    2008-12-01

    A review is presented of the design of suitable materials systems for joining by high-temperature plastic deformation, details of the joining techniques, microstructures and properties of the resulting composite bodies, and prospects and limitation for this type of joining technology. Joining parameters and resulting forms are discussed for Al{sub 2}O{sub 3}/mullite particulate composites, Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} particulate/Al{sub 2}O{sub 3} particulate and whisker-reinforced composites, hydroxyapatite bioceramics, La{sub 0.85}Sr{sub 0.15}MnO{sub 3} electronic ceramics, MgF{sub 2} optical ceramics, and Ni{sub 3}Al intermetallics. Results are contrasted with those obtained by other methods of joining brittle, high-temperature materials, with special focus on durability and mechanical properties.

  3. Microstructure and properties of ceramics and composites joined by plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Goretta, K.C. [Argonne National Laboratory, Argonne, IL 60439-4838 (United States)], E-mail: ken.goretta@aoard.af.mil; Singh, D.; Chen Nan [Argonne National Laboratory, Argonne, IL 60439-4838 (United States); Gutierrez-Mora, F.; Cinta Lorenzo-Martin, M. de la [Argonne National Laboratory, Argonne, IL 60439-4838 (United States); University of Seville, Seville 41080 (Spain); Dominguez-Rodriguez, A. [University of Seville, Seville 41080 (Spain); Routbort, J.L. [Argonne National Laboratory, Argonne, IL 60439-4838 (United States)

    2008-12-20

    A review is presented of the design of suitable materials systems for joining by high-temperature plastic deformation, details of the joining techniques, microstructures and properties of the resulting composite bodies, and prospects and limitation for this type of joining technology. Joining parameters and resulting forms are discussed for Al{sub 2}O{sub 3}/mullite particulate composites, Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} particulate/Al{sub 2}O{sub 3} particulate and whisker-reinforced composites, hydroxyapatite bioceramics, La{sub 0.85}Sr{sub 0.15}MnO{sub 3} electronic ceramics, MgF{sub 2} optical ceramics, and Ni{sub 3}Al intermetallics. Results are contrasted with those obtained by other methods of joining brittle, high-temperature materials, with special focus on durability and mechanical properties.

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

    Science.gov (United States)

    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.

  5. Structure-performance maps of polymeric, metal, and ceramic matrix composites

    Science.gov (United States)

    Chou, Tsu-Wei; Yang, Jenn-Ming

    1986-09-01

    This paper presents the results of extensive analytical studies of the thermo-elastic properties of unidirectional laminated composites, as well as two-dimensional and three-dimensional textile structural composites with polymeric, metal, and ceramic matrices. Some comparisons of the theoretical predictions with experimental data have been made. By the construction of the structure-performance maps, the effective composite properties based upon various reinforcement forms and fiber and matrix combinations can be easily assessed. The uniqueness of various textile structural reinforcements also has been demonstrated. These comprehensive performance maps can provide the data base necessary for material selections and guidance for future investigations of advanced composites.

  6. Advanced composite materials and processes

    Science.gov (United States)

    Baucom, Robert M.

    1991-01-01

    Composites are generally defined as two or more individual materials, which, when combined into a single material system, results in improved physical and/or mechanical properties. The freedom of choice of the starting components for composites allows the generation of materials that can be specifically tailored to meet a variety of applications. Advanced composites are described as a combination of high strength fibers and high performance polymer matrix materials. These advanced materials are required to permit future aircraft and spacecraft to perform in extended environments. Advanced composite precursor materials, processes for conversion of these materials to structures, and selected applications for composites are reviewed.

  7. Processing and characterization of pure cordierite and zirconia-doped cordierite ceramic composite by precipitation technique

    Indian Academy of Sciences (India)

    M Senthil Kumar; A Elaya Perumal; T R Vijayaram; Govindan Senguttuvan

    2015-06-01

    Pure cordierite and cordierite–ZrO2 composite (5–20 wt%) ceramics for various stoichiometric compositions were synthesized from standard raw materials by a novel precipitation technique. The analytical techniques such as X-ray diffraction, simultaneous thermogravimetric and differential thermal analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and bulk density were employed to evaluate the properties and microstructure. Results show that the ceramic composites consist of cordierite and zircon phases. The cordierite–zirconia (20 wt%) increased the fracture toughness value from 3.38 to 3.94 MPa, which is mainly due to martensitic transformation present in zirconia. The flexural strength of composite was found to increase from 126.46 to 297.62 MPa. The thermal expansion coefficients of cordierite and cordierite–zirconia (20 wt%) were 4.08 × 10−6 and 4.42 × 10−6 ° C−1 which may be due to the addition of zirconia.

  8. Creep Forming of Carbon-Reinforced Ceramic-Matrix Composites

    Science.gov (United States)

    Vaughn, Wallace L.; Scotti, Stephan J.; Ashe, Melissa P.; Connolly, Liz

    2007-01-01

    A set of lecture slides describes an investigation of creep forming as a means of imparting desired curvatures to initially flat stock plates of carbon-reinforced ceramic-matrix composite (C-CMC) materials. The investigation is apparently part of a continuing effort to develop improved means of applying small CCMC repair patches to reinforced carbon-carbon leading edges of aerospace vehicles (e.g., space shuttles) prior to re-entry into the atmosphere of the Earth. According to one of the slides, creep forming would be an intermediate step in a process that would yield a fully densified, finished C-CMC part having a desired size and shape (the other steps would include preliminary machining, finish machining, densification by chemical vapor infiltration, and final coating). The investigation included experiments in which C-CMC disks were creep-formed by heating them to unspecified high temperatures for time intervals of the order of 1 hour while they were clamped into single- and double-curvature graphite molds. The creep-formed disks were coated with an oxidation- protection material, then subjected to arc-jet tests, in which the disks exhibited no deterioration after exposure to high-temperature test conditions lasting 490 seconds.

  9. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  10. Elastic, dielectric, and piezoelectric properties of ceramic lead zirconate titanate/α-Al2O3 composites

    Science.gov (United States)

    Rybyanets, A. N.; Konstantinov, G. M.; Naumenko, A. A.; Shvetsova, N. A.; Makar'ev, D. I.; Lugovaya, M. A.

    2015-03-01

    The technology of producing ceramic lead zirconate titanate/α-Al2O3 composites has been developed. Elements of piezoactive composites containing from 0 to 60 vol % α-Al2O3 have been prepared. The elastic, dielectric, and piezoelectric parameters of the synthesized ceramic composites have been measured, and their microstructure has been studied. It has been found that the concentration dependences of the elastic and piezoelectric properties exhibit anomalies. The obtained data have been interpreted based on the percolation theory and the concept of microstructural constructing polycrystalline composition materials.

  11. Electrical resistivity of ceramic-metal composite materials in the percolation region: application in crucibles for induction furnaces; Resistividade eletrica de materiais compositos do tipo ceramica-metal na regiao de percolacao: aplicacao em cadinhos para fornos de inducao

    Energy Technology Data Exchange (ETDEWEB)

    Sene, Frank Ferrer

    1997-07-01

    Ceramic composite materials were produced by mixing powders of Partially Stabilized (PSZ) with titanium, niobium or nickel, and cristobalite with titanium. Pellets were produced by uniaxially pressing the material followed by cold isostatic pressing and finally sintering at 1600 deg C for 1,5 hours in argon. The metal content was varied in the range of 0-40 volume percent (v/o). Electrical resistivity measurements were performed in the temperature range of 25 - 700 deg C. Samples containing metallic inclusions above 25 v/o show the predominance of electronic type conducting. For samples with metallic inclusion below 25 v/o, a typically ionic conduction behavior has been observed. PSZ-Ti and PSZ-Ni samples containing 25 v/o of metallic inclusions show an insulator - conductor transition in a given temperature range. Cristobalite samples containing 30 v/o of titanium show a conductor - insulator transition also in a specific temperature range. Tests performed in an induction furnace showed that samples containing metallic inclusions above 25 v/o had self-heated when exposed to electro magnetic fields in the range of radio frequency (r.f.) Crucibles of PSZ-Ti were made by slip casting followed by sintering at 1600 deg C for 1.5 hours in argon. These crucibles were exposed to electromagnetic fields in the r.f. range and the maximum temperature reached was 1350 deg C. Microstructure characterization was performed on those materials by X-ray diffraction, EDS, optical and scanning electron microscopy. (author)

  12. Combustion Synthesis of h-BN-SiC Ceramic Composites

    Institute of Scientific and Technical Information of China (English)

    LI Hong-bo; ZHENG Yong-ting; ZHOU Li-juan; HAN Jie-cai

    2006-01-01

    The feasibility was demonstrated to fabricate h-BN-SiC ceramics through combustion synthesis of the mixture of boron carbide and silicon powders under 100 MPa nitrogen pressure. The mass fraction of BN and SiC in the combustion products were found to be 72 % and 28 % respectively. The thermodynamics of the synthesis reaction and the adiabatic combustion temperature were calculated on the theoretical ground. The bending strengths of the ceramics were measured to be 65.2 MPa at room temperature and 55 MPa at 1350 ℃. The phase composition and microstructure of the combustion products were identified by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

  13. Ceramic nanotubes for polymer composites with stable anticorrosion properties

    Science.gov (United States)

    Fakhrullin, R. F.; Tursunbayeva, A.; Portnov, V. S.; L'vov, Yu. M.

    2014-12-01

    The use of natural halloysite clay tubes 50 nm in diameter as nanocontainers for loading, storing, and slowly releasing organic corrosion inhibitors is described. Loaded nanotubes can be mixed well with many polymers and dyes in amounts of 5-10 wt % to form a ceramic framework (which increases the strength of halloysite composites by 30-50%), increase the adhesion of these coatings to metals, and allow for the slow release of corrosion inhibitors in defects of coatings. A significant improvement of protective anticorrosion properties of polyacryl and polyurethane coatings containing ceramic nanotubes loaded with benzotriazole and hydroxyquinoline is demonstrated.

  14. High-Temperature, Lightweight, Self-Healing Ceramic Composites for Aircraft Engine Applications

    Science.gov (United States)

    Raj, Sai V.; Bhatt, Ramkrishna

    2013-01-01

    The use of reliable, high-temperature, lightweight materials in the manufacture of aircraft engines is expected to result in lower fossil and biofuel consumption, thereby leading to cost savings and lower carbon emissions due to air travel. Although nickel-based superalloy blades and vanes have been successfully used in aircraft engines for several decades, there has been an increased effort to develop high-temperature, lightweight, creep-resistant substitute materials under various NASA programs over the last two decades. As a result, there has been a great deal of interest in developing SiC/SiC ceramic matrix composites (CMCs) due to their higher damage tolerance compared to monolithic ceramics. Current-generation SiC/SiC ceramic matrix composites rely almost entirely on the SiC fibers to carry the load, owing to the premature cracking of the matrix during loading. Thus, the high-temperature usefulness of these CMCs falls well below their theoretical capabilities. The objective of this work is to develop a new class of high-temperature, lightweight, self-healing, SiC fiber-reinforced, engineered matrix ceramic composites.

  15. On the tensile strength of a fiberreinforced ceramic composite containing a crack-like flaw

    Science.gov (United States)

    Budiansky, Bernard; Cui, Yingqing Lawrence

    1994-01-01

    T HE TENSILE STRENGTH of a fiber-reinforced ceramic composite containing a through-the-fiber flaw in the form of a sharp crack is studied. The strength of a brittle unreinforced ceramic containing a sharp crack of length 2 a0, subjected to uniaxial load in the direction normal to the crack plane, is given by linear elastic fracture mechanics as σ s = Km/√π a0, where km is the fracture toughness of the material. However, for a fiber-reinforced ceramic, the strength can only be determined on the basis of a full analysis of crack growth in the matrix and the failure of crack-bridging fibers. The tensile strength of a flawed ceramic material that is reinforced by fibers aligned in the direction perpendicular to the flaw surfaces is studied in this paper. Crack-bridging fibers are assumed to slip relative to the matrix when a critical interface shear stress is reached. The orthotropy of the composite produced by the presence of aligned fibers is rigorously accounted for in the analysis. The dependence of the composite tensile strength on fiber tensile strength, matrix toughness, flaw-size and frictional shear stress at the fiber-matrix interface is determined and described in terms of a universal set of non-dimensional parameters.

  16. Failure Modes in Composite Materials.

    Science.gov (United States)

    1987-05-19

    Derek, An Introduction to Composite Materials , New York: Cambridge University Press, 1981. 12. Jamison, R. D., Mechanical Engineering Department...1978. 19. Tsai, Stephen W., Introduction to Composite Materials , Lancaster, Pennsylvania: Technomic Publishing Company, Inc., 1980. 4,’ * .20. Vernon

  17. Water reservoir as resource of raw material for ceramic industry

    Science.gov (United States)

    Irie, M.; Tarhouni, J.

    2015-04-01

    The industries related to the ceramics such as construction bricks, pottery and tile are the important sectors that cover the large part of the working population in Tunisia. The raw materials, clay or silt are excavated from opencast site of limestone clay stratum. The opencast site give the negative impact on landscape and environment, risks of landslide, soil erosion etc. On the other hand, a most serious problem in water resource management, especially in arid land such as Tunisia, is sedimentation in reservoirs. Sediment accumulation in the reservoirs reduces the water storage capacity. The authors proposed the exploitation of the sediment as raw material for the ceramics industries in the previous studies because the sediment in Tunisia is fine silt. In this study, the potential of the water reservoirs in Tunisia as the resource of the raw material for the ceramics industries is estimated from the sedimentation ratio in the water reservoirs.

  18. Glass-ceramic materials from electric arc furnace dust.

    Science.gov (United States)

    Kavouras, P; Kehagias, T; Tsilika, I; Kaimakamis, G; Chrissafis, K; Kokkou, S; Papadopoulos, D; Karakostas, Th

    2007-01-31

    Electric arc furnace dust (EAFD) was vitrified with SiO2, Na2CO3 and CaCO3 powders in an electric furnace at ambient atmosphere. Vitreous products were transformed into glass-ceramic materials by two-stage heat treatment, at temperatures determined by differential thermal analysis. Both vitreous and glass-ceramic materials were chemically stable. Wollastonite (CaSiO3) was separated from the parent matrix as the dominant crystalline phase, verified by X-ray diffraction analysis and energy dispersive spectrometry. Transmission electron microscopy revealed that wollastonite crystallizes mainly in its monoclinic form. Knoop microhardness was measured with the static indentation test method in all initial vitreous products and the microhardness values were in the region of 5.0-5.5 GPa. Devitrification resulted in glass-ceramic materials with microhardness values strongly dependent on the morphology and orientation of the separated crystal phase.

  19. Evaluation of a Variable-Impedance Ceramic Matrix Composite Acoustic Liner

    Science.gov (United States)

    Jones, M. G.; Watson, W. R.; Nark, D. M.; Howerton, B. M.

    2014-01-01

    As a result of significant progress in the reduction of fan and jet noise, there is growing concern regarding core noise. One method for achieving core noise reduction is via the use of acoustic liners. However, these liners must be constructed with materials suitable for high temperature environments and should be designed for optimum absorption of the broadband core noise spectrum. This paper presents results of tests conducted in the NASA Langley Liner Technology Facility to evaluate a variable-impedance ceramic matrix composite acoustic liner that offers the potential to achieve each of these goals. One concern is the porosity of the ceramic matrix composite material, and whether this might affect the predictability of liners constructed with this material. Comparisons between two variable-depth liners, one constructed with ceramic matrix composite material and the other constructed via stereolithography, are used to demonstrate this material porosity is not a concern. Also, some interesting observations are noted regarding the orientation of variable-depth liners. Finally, two propagation codes are validated via comparisons of predicted and measured acoustic pressure profiles for a variable-depth liner.

  20. Additive Manufacturing of Silicon Carbide-Based Ceramic Matrix Composites: Technical Challenges and Opportunities

    Science.gov (United States)

    Singh, Mrityunjay; Halbig, Michael C.; Grady, Joseph E.

    2016-01-01

    Advanced SiC-based ceramic matrix composites offer significant contributions toward reducing fuel burn and emissions by enabling high overall pressure ratio (OPR) of gas turbine engines and reducing or eliminating cooling air in the hot-section components, such as shrouds, combustor liners, vanes, and blades. Additive manufacturing (AM), which allows high value, custom designed parts layer by layer, has been demonstrated for metals and polymer matrix composites. However, there has been limited activity on additive manufacturing of ceramic matrix composites (CMCs). In this presentation, laminated object manufacturing (LOM), binder jet process, and 3-D printing approaches for developing ceramic composite materials are presented. For the laminated object manufacturing (LOM), fiber prepreg laminates were cut into shape with a laser and stacked to form the desired part followed by high temperature heat treatments. For the binder jet, processing optimization was pursued through silicon carbide powder blending, infiltration with and without SiC nano powder loading, and integration of fibers into the powder bed. Scanning electron microscopy was conducted along with XRD, TGA, and mechanical testing. Various technical challenges and opportunities for additive manufacturing of ceramics and CMCs will be presented.

  1. Influence of Mo addition on dielectric properties of AlN ceramic matrix composites

    Science.gov (United States)

    Zhang, Yan; Yang, Zhimin; Ma, Huina; Du, Jun

    2009-03-01

    AlN-Mo composite ceramics were prepared by spark plasma sintering (SPS) with CaF2 as sintering aids. Effect of Mo addition on the thermal conductivity and dielectric properties of the composite ceramics had been studied. The results show that the room temperature thermal conductivity increases with increasing the content of Mo, and the value begins to decrease slightly when the Mo concentration exceeds 20 vol. %. Analyses indicate that the key factors to dielectric properties are the metal phase concentration and the microstructure of Mo particles. 1 vol. % Ni has been added into the composite ceramics to change the distribution of the Mo phase. The elongated shape particles which link with each other have a tendency to acquire rounded forms which are thermodynamically more stable. Consequently, the dielectric constant and loss of the composite ceramics could be adjusted and the material becomes an electrical conductor in the case of Mo volume fraction of more than 23%. Furthermore, the dielectric properties could be improved to a large extent by transforming the microstructure of the metal particles when the concentration of Mo is fixed.

  2. Investigation of Coating Capability of Composite Materials

    Directory of Open Access Journals (Sweden)

    Yelda Akçin

    2013-07-01

    Full Text Available Nowadays, composite materials are widely used in the sectors that are overrated high strength / density and high elasticity modulus / density ratios such as defense industry, marine transportation, automotive and aerospace industry. However, because of the surface properties such as tribological behavior and low wear resistance their application areas are limited. Coating is the prominent process in order to improve these properties of the materials. In this study, hard ceramic powders (Al2O3 + TiO2 and CrO3 are coated to surface of glass fiber and carbon fiber reinforced epoxy matrix composite materials with plasma spray coating method started to be widely used todays and physical, mechanical and metallographic properties of obtained coatings were examined.

  3. Carbon nanotubes-porous ceramic composite by in situ CCVD growth of CNTs

    Energy Technology Data Exchange (ETDEWEB)

    Mazumder, Sangram; Sarkar, Naboneeta; Park, Jung Gyu [Institute of Processing and Application of Inorganic Materials (PAIM), Department of Materials Science and Engineering, Hanseo University, #360 Daegok-ri, Haemi-myeon, Seosan-si, Chungnam, 356-706 (Korea, Republic of); Han, In Sub [Korea Institute of Energy Research (KIER), #152 Gajeong-gu, Daejeon 305-343 (Korea, Republic of); Kim, Ik Jin, E-mail: ijkim@hanseo.ac.kr [Institute of Processing and Application of Inorganic Materials (PAIM), Department of Materials Science and Engineering, Hanseo University, #360 Daegok-ri, Haemi-myeon, Seosan-si, Chungnam, 356-706 (Korea, Republic of)

    2016-03-01

    A novel approach towards the formation of Carbon nanotubes-porous alumina ceramic composite was attempted by the application of three different reaction techniques. Porous alumina ceramics having micrometer pore dimensions were developed using the direct foaming technique. NaA zeolites were simultaneously synthesized and coated within the porous ceramics by an in situ hydrothermal process and were subjected to a simple ion exchange reaction for preparing the suitable catalyst material for Carbon nanotubes (CNTs) synthesis. The catalytic chemical vapour deposition (CCVD) technique was used to grow CNTs within the porous ceramics and the effect of growth time on the synthesized CNTs were investigated. Phase compositions of the samples were analysed by X-ray diffractometer (XRD). Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) were used for morphology, surface quality and structural analysis. Crystallinity, defects and yield were studied by Raman spectroscopy and thermogravimetric analysis (TGA). - Highlights: • Novel processing route of MWCNTs grown on Cobalt-zeolites-porous ceramics by CCVD. • CCVD time of 120 min produced MWCNTs with most prominent tube-like structure. • 120 min produced highest yield (19.46%) of CNTs with an I{sub D}/I{sub G} ratio of 0.88.

  4. Effect of Static and Cyclic Loading on Ceramic Laminate Veneers Adhered to Teeth with and Without Aged Composite Restorations

    NARCIS (Netherlands)

    Gresnigt, Marco M. M.; Ozcan, Mutlu; Kalk, Warner; Galhano, Graziela

    2011-01-01

    Purpose: Existing composite restorations on teeth are often remade prior to the cementation of fixed dental prostheses. The aim of this study was to evaluate the effect of static and cyclic loading on ceramic laminate veneers adhered to aged resin composite restorations. Materials and Methods: Eight

  5. Effects of Processing Technology on Property and Microstructure of Rare Earth Containing Ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    Xu Chonghai

    2004-01-01

    Effects of processing technology on the properties such as relative density, flexural strength, fracture toughness, hardness, etc. and the microstructure of rare earth yttrium containing Al2O3/(W, Ti)C ceramic composite were experimentally investigated. It suggests that different processing parameters can undoubtedly result in different microstructures and different mechanical properties of the material. Under the experimental conditions, the suitable hot pressing temperature is 1720 ~ 1780 ℃, the time duration is 10 ~ 30 min and the hot pressing pressure is 30 ~ 35 MPa. The corresponding relative density can even be higher than 98 %. With SEM and TEM observation, each phases in the ceramic material is found to be in fine grains and distribute homogeneously. Typical fracture feature of the material is the mixture of both intergranular and introgranular fracture. Additionally, the existence of rare earth yttrium containing nanometer or sub-micron meter sized ceramic grains, dislocations and spontaneous microcracks can also contribute to the further improvement of the mechanical properties of the ceramic composite.

  6. Ceramic composites with a ductile Ni{sub 3}Al binder phase

    Energy Technology Data Exchange (ETDEWEB)

    Tiegs, T.N.; Alexander, K.B.; Plucknett, K.P.; Menchhofer, P.A.; Becher, P.F.; Waters, S.B.

    1995-06-01

    Composites using B-doped ductile Ni{sub 3}Al alloys were produced with both non-oxide (WC, TiC) and oxide (Al{sub 2}0{sub 3}) ceramic powders. Typical powder processing techniques were used to fabricate materials with ceramic contents from 0-95 vol. %. The microstructural morphology of the composites depends primarily on the wetting behavior between the alloys and the ceramic powders. The non-oxide ceramic powders wet well and the Ni{sub 3}Al alloys form a semi-continuous intergranular phase. On the other hand, the Ni{sub 3}Al alloys do not wet the oxide powders well and tend to form discrete ``islands`` of the metallic phase. Wetting in these materials can be improved by the addition of non-oxide particles, such as TiC. Results on the mechanical properties showed ambient temperature flexural strength similar to other Ni-based hardmetals. In contrast to the WC-Co materials, the flexural strength is retained to temperatures of at least 800 C. The fracture toughness and hardness were found to be equal or higher than comparable Co-based hardmetal systems. Initial corrosion tests showed excellent resistance to acid solutions.

  7. Effect of ceramic thickness and composite bases on stress distribution of inlays--a finite element analysis.

    Science.gov (United States)

    Durand, Letícia Brandão; Guimarães, Jackeline Coutinho; Monteiro Junior, Sylvio; Baratieri, Luiz Narciso

    2015-01-01

    The purpose of this study was to determine the effect of cavity depth, ceramic thickness, and resin bases with different elastic modulus on von Mises stress patterns of ceramic inlays. Tridimensional geometric models were developed with SolidWorks image software. The differences between the models were: depth of pulpal wall, ceramic thickness, and presence of composite bases with different thickness and elastic modulus. The geometric models were constrained at the proximal surfaces and base of maxillary bone. A load of 100 N was applied. The stress distribution pattern was analyzed with von Mises stress diagrams. The maximum von Mises stress values ranged from 176 MPa to 263 MPa and varied among the 3D-models. The highest von Mises stress value was found on models with 1-mm-thick composite resin base and 1-mm-thick ceramic inlay. Intermediate values (249-250 MPa) occurred on models with 2-mm-thick composite resin base and 1-mm-thick ceramic inlay and 1-mm-thick composite resin base and 2-mm-thick ceramic inlay. The lowest values were observed on models restored exclusively with ceramic inlay (176 MPa to 182 MPa). It was found that thicker inlays distribute stress more favorably and bases with low elastic modulus increase stress concentrations on the internal surface of the ceramic inlay. The increase of ceramic thickness tends to present more favorable stress distribution, especially when bonded directly onto the cavity without the use of supporting materials. When the use of a composite base is required, composite resin with high elastic modulus and reduced thickness should be preferred.

  8. Ceramic/polymer functionally graded material (FGM) lightweight armor system

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.; McClellan, K.J.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Functionally graded material is an enabling technology for lightweight body armor improvements. The objective was to demonstrate the ability to produce functionally graded ceramic-polymer and ceramic-metal lightweight armor materials. This objective involved two aspects. The first and key aspect was the development of graded-porosity boron-carbide ceramic microstructures. The second aspect was the development of techniques for liquid infiltration of lightweight metals and polymers into the graded-porosity ceramic. The authors were successful in synthesizing boron-carbide ceramic microstructures with graded porosity. These graded-porosity boron-carbide hot-pressed pieces were then successfully liquid-infiltrated in vacuum with molten aluminum at 1,300 C, and with liquid polymers at room temperature. Thus, they were able to demonstrate the feasibility of producing boron carbide-aluminum and boron carbide-polymer functionally graded materials.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Modeling and simulation of continuous fiber-reinforced ceramic composites

    Science.gov (United States)

    Bheemreddy, Venkata

    Finite element modeling framework based on cohesive damage modeling, constitutive material behavior using user-material subroutines, and extended finite element method (XFEM), are developed for studying the failure behavior of continuous fiber-reinforced ceramic matrix composites (CFCCs) by the example of a silicon carbide matrix reinforced with silicon carbide fiber (SiC/SiCf) composite. This work deals with developing comprehensive numerical models for three problems: (1) fiber/matrix interface debonding and fiber pull-out, (2) mechanical behavior of a CFCC using a representative volume element (RVE) approach, and (3) microstructure image-based modeling of a CFCC using object oriented finite element analysis (OOF). Load versus displacement behavior during a fiber pull-out event was investigated using a cohesive damage model and an artificial neural network model. Mechanical behavior of a CFCC was investigated using a statistically equivalent RVE. A three-step procedure was developed for generating a randomized fiber distribution. Elastic properties and damage behavior of a CFCC were analyzed using the developed RVE models. Scattering of strength distribution in CFCCs was taken into account using a Weibull probability law. A multi-scale modeling framework was developed for evaluating the fracture behavior of a CFCC as a function of microstructural attributes. A finite element mesh of the microstructure was generated using an OOF tool. XFEM was used to study crack propagation in the microstructure and the fracture behavior was analyzed. The work performed provides a valuable procedure for developing a multi-scale framework for comprehensive damage study of CFCCs.

  11. Constructing of cure monitoring system with piezoelectric ceramics for composite laminate

    Science.gov (United States)

    Oshima, Nobuo; Inoue, Kouichi; Motogi, Shinya; Fukuda, Takehito

    2003-08-01

    The cure monitoring system with piezoelectric ceramics is constructed. An embedded type piezoelectric ceramics sensor with flat lead wires is developed. And the piezoelectric ceramics is embedded into composite laminate. A dummy piezoelectric ceramics is set in the autoclave oven. The impedance of the piezoelectric ceramics which is embedded in the composite laminate and that of the dummy piezoelectric ceramics are measured by a LCR meter. The piezoelectric ceramics have strong temperature dependency. The temperature dependency of the impedance of piezoelectric ceramics is corrected by the information from the dummy piezoelectric ceramics. A dielectric sensor is also embedded in the composite laminate as a reference sensor for the degree of cure. The change in calculated cure index shows good correspondence with change in the log ion viscosity which is measured by the dielectric cure monitoring sensor.

  12. Metals and Ceramics Division materials science annual progress report for period ending June 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. (comp.)

    1977-09-01

    Progress is reported for research programs in the metals and ceramics division of ORNL. In structure of materials, theoretical research, x-ray diffraction studies, studies of erosion of ceramics, preparation and synthesis of high temperature and special service materials, and studies of stabilities of microphases in high-temperature structural materials. Research into deformation and mechanical properties included physical metallurgy, and grain boundary segregation and embrittlement. Physical properties and transport phenomena were studied and included mechanisms of surface and solid state reactions, and properties of superconducting materials. The radiation effects program, directed at understanding the effects of composition and microstructure on the structure and properties of materials irradiated at elevated temperatures, is also described. (GHT)

  13. Effects of surface-conditioning methods on shear bond strength of brackets bonded to different all-ceramic materials.

    Science.gov (United States)

    Saraç, Y Şinasi; Külünk, Tolga; Elekdağ-Türk, Selma; Saraç, Duygu; Türk, Tamer

    2011-12-01

    The aims of this study were to investigate the effects of two surface-conditioning methods on the shear bond strength (SBS) of metal brackets bonded to three different all-ceramic materials, and to evaluate the mode of failure after debonding. Twenty feldspathic, 20 fluoro-apatite, and 20 leucite-reinforced ceramic specimens were examined following two surface-conditioning methods: air-particle abrasion (APA) with 25 μm Al(2)O(3) and silica coating with 30 μm Al(2)O(3) particles modified by silica. After silane application, metal brackets were bonded with light cure composite and then stored in distilled water for 1 week and thermocycled (×1000 at 5-55°C for 30 seconds). The SBS of the brackets was measured on a universal testing machine. The ceramic surfaces were examined with a stereomicroscope to determine the amount of composite resin remaining using the adhesive remnant index. Two-way analysis of variance, Tukey's multiple comparison test, and Weibull analysis were used for evaluation of SBS. The lowest SBS was with APA for the fluoro-apatite ceramic (11.82 MPa), which was not significantly different from APA for the feldspathic ceramic (13.58 MPa). The SBS for the fluoro-apatite ceramic was significantly lower than that of leucite-reinforced ceramic with APA (14.82 MPa). The highest SBS value was obtained with silica coating of the leucite-reinforced ceramic (24.17 MPa), but this was not significantly different from the SBS for feldspathic and fluoro-apatite ceramic (23.51 and 22.18 MPa, respectively). The SBS values with silica coating showed significant differences from those of APA. For all samples, the adhesive failures were between the ceramic and composite resin. No ceramic fractures or cracks were observed. Chairside tribochemical silica coating significantly increased the mean bond strength values.

  14. Strength and thickness of the layer of materials used for ceramic veneers bonding.

    Science.gov (United States)

    Mazurek, Karolina; Mierzwińska-Nastalska, Elżbieta; Molak, Rafał; Kożuchowski, Mariusz; Pakieła, Zbigniew

    2012-01-01

    The use of adhesive bonding systems and composites in prosthetic dentistry brought improved and more aesthetic prosthetic restorations. The adhesive bonding of porcelain veneers is based on the micromechanical and chemical bond between tooth surface, cement layer and ceramic material. The aim of the study was to measure the thickness of the material layer formed during cementing of a ceramic restoration, and - in the second part of the study - to test tension of these cements. The materials investigated comprised dual-curing materials: Variolink II, KoNroot Cem, KoNroot Cem Viscous and Panavia F 2.0, as well as a light-curing composite: Variolink Veneer. The thickness was measured with the use of ZIP Lite 250 optical gauging apparatus. SEM microscope - Hitachi Tabletop Microscope TM-100 - was used to analyse the characteristics of an adhesive bond and filler particle size of particular materials. Tension tests of the cements under study were carried out on the MTS Q Test 10 static electrodynamic apparatus. The tests showed that KoNroot Cem exhibited the best mechanical properties of bonding to enamel and dentin among the materials tested. Variolink II base light-curing cement formed the thinnest layer. All the materials tested formed the layer not exceeding 1/3 of ceramic restoration thickness.

  15. Flexible Ceramic-Metal Insulation Composite and Method of Making

    Science.gov (United States)

    Rasky, Daniel J. (Inventor); Sawko, Paul M. (Inventor); Kilodziej, Paul (Inventor); Kourtides, Demetrius A. (Inventor)

    1998-01-01

    A method for joining a woven flexible ceramic fabric and a thin metal sheet creating an integral metal surfaced flexible thermal protection article, which methods compress: placing multiple dots of high temperature metallic or fabric and the thin metal sheet in a random or organized pattern, with the proviso that the brazing material covers about 10% or less of the surface of one flat side of the metal sheet; heating the flexible ceramic fabric, brazing material and thin metal sheet for a predetermined period of time to integrally connect the same; and cooling the formed flexible article to ambient temperature. Preferably the flexible ceramic is selected from fibers comprising atoms of silicon, carbon, nitrogen, boron, oxygen or combinations thereof. The flexible thermal protection article produced is also part of the present invention. The thin metal sheet is comprised of titanium, aluminum, chromium, niobium or alloys or combinations thereof. The brazing material is selected from copper/silver or copper/gold or is a ceramic brazing or adhesive material.

  16. Composite materials processing, applications, characterizations

    CERN Document Server

    2017-01-01

    Composite materials are used as substitutions of metals/traditional materials in aerospace, automotive, civil, mechanical and other industries. The present book collects the current knowledge and recent developments in the characterization and application of composite materials. To this purpose the volume describes the outstanding properties of this class of advanced material which recommend it for various industrial applications.

  17. Approach to microstructure-behavior relationships for ceramic matrix composites reinforced by continuous fibers

    Directory of Open Access Journals (Sweden)

    Lamon Jacques

    2015-01-01

    Full Text Available Ceramic matrix composites (CMCs reinforced with continuous fibers exhibit several features that differentiate them from homogeneous unreinforced materials. The microstructure consists of various distinct constituents: fibres, matrix, and fiber/matrix interfaces or interphases. Several entities at micro- and mesoscopic length scales can be defined depending on fiber arrangement. Furthermore, the CMCs contain flaw populations that govern matrix cracking and fiber failures. The paper describes the microstructure-behavior relations for ceramic matrix composites reinforced with continuous fibers. It focuses on matrix damage by multiple cracking, on ultimate fracture, on delayed fracture at high temperatures, and on stochastic features induced by flaw populations. Models of damage and ultimate failure are based on micromechanics and fracture probabilities. They provide a basis for a multiscale approach to composite and component design.

  18. Thermal/chemical degradation of ceramic cross-flow filter materials

    Energy Technology Data Exchange (ETDEWEB)

    Alvin, M.A.; Lane, J.E.; Lippert, T.E.

    1989-11-01

    This report summarizes the 14-month, Phase 1 effort conducted by Westinghouse on the Thermal/Chemical Degradation of Ceramic Cross-Flow Filter Materials program. In Phase 1 expected filter process conditions were identified for a fixed-bed, fluid-bed, and entrained-bed gasification, direct coal fired turbine, and pressurized fluidized-bed combustion system. Ceramic cross-flow filter materials were also selected, procured, and subjected to chemical and physical characterization. The stability of each of the ceramic cross-flow materials was assessed in terms of potential reactions or phase change as a result of process temperature, and effluent gas compositions containing alkali and fines. In addition chemical and physical characterization was conducted on cross-flow filters that were exposed to the METC fluid-bed gasifier and the New York University pressurized fluidized-bed combustor. Long-term high temperature degradation mechanisms were proposed for each ceramic cross-flow material at process operating conditions. An experimental bench-scale test program is recommended to be conducted in Phase 2, generating data that support the proposed cross-flow filter material thermal/chemical degradation mechanisms. Papers on the individual subtasks have been processed separately for inclusion on the data base.

  19. Esthetic integration between ceramic veneers and composite restorations: a case report.

    Science.gov (United States)

    Farronato, Davide; Mangano, Francesco; Pieroni, Stefano; Lo Giudice, Giuseppe; Briguglio, Roberto; Briguglio, Francesco

    2012-07-01

    The tooth structure preservation is the best way to postpone more invasive therapies. Especially in young patients more conservative techniques should be applied. Bonded porcelain veneers and even more the direct composite restorations, are the two therapeutic procedures that require the fewer sacrifice of dental tissue, finalized to the optimal recovery of aesthetic and functional outcome.Although the two techniques require different methods and materials, is possible to achieve a correct integration of both the methods by some technical and procedural measures. In the presented case is planned a rehabilitation of the four upper incisors by ceramic veneers and direct composite restorations.Care is taken for the surface treatment of ceramic restorations, with the objective of achieving integration, not only between natural teeth and restorations, but also between the different materials in use.The purpose of this article is to show how a proper design of the treatment plan leads to obtain predictable results with both direct and indirect techniques.

  20. The effect of various primers on shear bond strength of zirconia ceramic and resin composite

    Directory of Open Access Journals (Sweden)

    Sasiwimol Sanohkan

    2013-01-01

    Full Text Available Aims: To determine the in vitro shear bond strengths (SBS of zirconia ceramic to resin composite after various primer treatments. Materials and Methods: Forty zirconia ceramic (Zeno, Wieland Dental specimens (10 mm in diameter and 2 mm thick were prepared, sandblasted with 50 μm alumina, and divided into four groups (n = 10. Three experimental groups were surface treated with three primers; CP (RelyX Ceramic Primer, 3M ESPE, AP (Alloy Primer, Kuraray Medical, and MP (Monobond Plus, Ivoclar Vivadent AG. One group was not treated and served as the control. All specimens were bonded to a resin composite (Filtek Supreme XT, 3M ESPE cylinder with an adhesive system (Adper Scotchbond Multi-Purpose Plus Adhesive, 3M ESPE and then stored in 100% humidity at 37°C for 24 h before SBS testing in a universal testing machine. Mean SBS (MPa were analyzed with one-way analysis of variance (ANOVA and the Tukey′s Honestly Significant Difference (HSD test (α = 0.05. Results: Group AP yielded the highest mean and standard deviation (SD value of SBS (16.8 ± 2.5 MPa and Group C presented the lowest mean and SD value (15.4 ± 1.6 MPa. The SBS did not differ significantly among the groups (P = 0.079. Conclusions: Within the limitations of this study, the SBS values between zirconia ceramic to resin composite using various primers and untreated surface were not significantly different.

  1. Porous Ceramic Composite ZrO2(MgO)-MgO for Osteoimplantology

    Science.gov (United States)

    Buyakov, A. S.; Kulkov, S. N.

    2017-02-01

    Pore and crystalline structure, biocompatibility of ceramic composite ZrO2(MgO)-MgO were studied. The main mechanical characteristics were determined and it has been shown that compression strength directly depends on microstresses obtained from X-ray data. In-vitro studies of mesenchymal stromal stem cells (MMSC), cultivated on material surface are shown that cell proliferation and differentiation of MMSC goes throw osteogenic type.

  2. Deformation and Damage Accumulation in a Ceramic Composite under Dynamic Loading

    Science.gov (United States)

    Korobenkov, M. V.; Kulkov, S. N.; Naymark, O. B.; Khorechko, U. V.; Ruchina, A. V.

    2016-01-01

    Methods of computer modelling were used to investigate the processes of deformation and microdamage formation in ceramic composite materials under intense dynamic loading. It was shown that there was no damage caused by dynamic compression in the vicinity of phase borders of a nanostructured aluminum oxide matrix and reinforcing particles of tetragonal zirconium dioxide. Also, the local origination of microdamages occurs only in the zones close to micropores.

  3. Chemistry of electronic ceramic materials. Proceedings of the International Conference on the Chemistry of Electronic Ceramic Materials

    Science.gov (United States)

    Davies, P. K.; Roth, R. S.

    1991-01-01

    The conference was held at Jackson Hole, Wyoming from August 17 to 22, 1990, and in an attempt to maximize the development of this rapidly moving, multidisciplinary field, this conference brought together major national and international researchers to bridge the gap between those primarily interested in the pure chemistry of inorganic solids and those interested in the physical and electronic properties of ceramics. With the many major discoveries that have occurred over the last decade, one of the goals of this meeting was to evaluate the current understanding of the chemistry of electronic ceramic materials, and to assess the state of a field that has become one of the most important areas of advanced materials research. The topics covered include: crystal chemistry; dielectric ceramics; low temperature synthesis and characterization; solid state synthesis and characterization; surface chemistry; superconductors; theory and modeling.

  4. Influence of Inclusion Shape on Thermoelasto-Plastic Optimun Design of Ceramic Metal Functionally Graded Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A nonlinear finite element method is applied to observe how inclusion shape influence the thermal response of a ceramic-metal functionally graded material (FGM).The elastic and plastic behaviors of the layers which are two-phase isotropic composites consisting of randomly oriented elastic spheroidal inclusions and a ductile matrix are predicted by a mean field method.The prediction results show that inclusion shape has remarkable influence on the overall behavior of the composite.The consequences of the thermal response analysis of the FGM are that the response is dependent on inclusion shape and its composition profile cooperatively and that the plastic behavior of each layer should be taken into account in optimum design of a ceramic-metal FGM.

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

    Science.gov (United States)

    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

  6. Mechanical properties of silver matrix composites reinfroced with ceramic particles

    Directory of Open Access Journals (Sweden)

    J. Śleziona

    2006-04-01

    Full Text Available Purpose: Silver, silver alloys, as well as silver matrix based composites have been well known and applied in the electrotechnical and electronics industry for several decades. For many applications in electrotechnology, including electric contacts and brushes, unreinforced sliver alloys do not meet the requirements concerning mainly durability and wear resistance, first of all to tribological and electroerosive wear. These wear processes may be prevented by introducing to silver reinforcement particles and alloys. The target of the research included basic mechanical properties determination of the silver matrix composites reinforced with ceramic particles, manufactured with the use of suspension methods.Design/methodology/approach: In the presented paper the authors demonstrate possibilities of manufacturing of silver matrix composites on the way of casting technology utilization.Findings: The results of the research prove that applied suspension technology, based on introducing of agglomerated foundry alloy which is the carrier for reinforcement particles (SiC lub Al2O3 allows to produce in an effective and, what is important, in an economically attractive way, sliver alloys based composites.Research limitations/implications: The researches on the structure of manufactured composites and their mechanical properties that are presented in the paper prove the possibilities of mechanical mixing technology application for producing mechanical and stable connection between silver matrix and ceramic particles of aluminium oxide and silicon carbide.Originality/value: The manufacturing of this type of composites is based most of all on the utilization of powder metallurgy techniques. However the obtained results of the research prove that there is a possibility of silver matrix composites forming in the casting and plastic working processes. Extrusion process carried out in the hydraulic press KOBO has its favourably influence on ceramic reinforcement

  7. Advanced composite materials for optomechanical systems

    Science.gov (United States)

    Zweben, Carl

    2013-09-01

    Polymer matrix composites (PMCs) have been well established in optomechanical systems for several decades. The other three classes of composites; metal matrix composites (MMCs), ceramic matrix composites (CMCs), and carbon matrix composites (CAMCs) are making significant inroads. The latter include carbon/carbon (C/C) composites (CCCs). The success of composites has resulted in increasing use in consumer, industrial, scientific, and aerospace/defense optomechanical applications. Composites offer significant advantages over traditional materials, including high stiffnesses and strengths, near-zero and tailorable coefficients of thermal expansion (CTEs), tailorable thermal conductivities (from very low to over twice that of copper), and low densities. In addition, they lack beryllium's toxicity problems. Some manufacturing processes allow parts consolidation, reducing machining and joining operations. At present, PMCs are the most widely used composites. Optomechanical applications date from the 1970s. The second High Energy Astrophysical Observatory spacecraft, placed in orbit in 1978, had an ultrahigh-modulus carbon fiber-reinforced epoxy (carbon/epoxy) optical bench metering structure. Since then, fibers and matrix materials have advanced significantly, and use of carbon fiber-reinforced polymers (CFRPs) has increased steadily. Space system examples include the Hubble Space Telescope metering truss and instrument benches, Upper Atmosphere Research Satellite (UARS), James Webb Space Telescope and many others. Use has spread to airborne applications, such as SOFIA. Perhaps the most impressive CFRP applications are the fifty-four 12m and twelve 7m moveable ground-based ALMA antennas. The other three classes of composites have a number of significant advantages over PMCs, including no moisture absorption or outgassing of organic compounds. CCC and CMC components have flown on a variety of spacecraft. MMCs have been used in space, aircraft, military and industrial

  8. Mechanical behavior of ceramic composite hot-gas filters after exposure to severe environments

    Energy Technology Data Exchange (ETDEWEB)

    Pysher, D.J.; Weaver, B.L.; Smith, R.G. [Ceramic Technology Center, St. Paul, MN (United States)] [and others

    1995-08-01

    A novel type of hot-gas filter based on a ceramic fiber reinforced ceramic matrix has been developed, as reported at previous Fossil Energy Materials Conferences, through research activities at Oak Ridge National Laboratory (ORNL) and at the 3M Company. Simulated testing has been done at the Westinghouse Science and Technology Center. This filter technology has been extended to full size, 60 mm OD by 1.5 meter long candle filters and a commercially viable process for producing the filters has been developed filters are undergoing testing and demonstration use throughout the world for applications in pressurized fluidized-bed combustion (PFBC) and integrated gasification combined cycle (IGCC) plants. Demonstration tests of this ceramic composite filter along with other filters are in progress at the Tidd PFBC plant Mechanical tests were performed on the 3 M brand Ceramic Composite Candle Filter after exposure to various corrosive environments in order to assess its ability to function as a hot gas filter in coal-fired applications. Due to the different construction of ceramic composite filters and the thin composite wall versus the typical thick-walled monolithic filter, standard mechanical property tests had to be refined or modified to accurately determine the filters properties. These tests and filter property results will be described Longitudinal tensile and diametral O-ring compression tests were performed on as-produced candle filters as well as on filters which had been exposed to various environments. The exposures were for 1000 hrs at 850{degrees}C in wet air, in wet air containing Na{sub 2}CO{sub 3}, and in wet air containing NaCl. In addition, a filter which bad been coated with ash (Old Grimethorpe) was exposed to wet air at 850{degrees}C for 1000 hours.

  9. BN interphase in composite materials with nicalon Si-C-O fibers and with vitro ceramic matrix of MAS type; L`interphase BN dans les materiaux composites a fibres Si-C-O nicalon et a matrice vitroceramique de type MAS

    Energy Technology Data Exchange (ETDEWEB)

    Ricca, N.

    1994-03-14

    BN has been suggested as an interphase in silica-based glass-ceramic matrix composites with a view to use these materials in oxidizing atmospheres at medium or high temperatures. The matrix had a boron-doped MAS (MgO-Al{sub 2}O{sub 3}-SiO{sub 2}) composition and was prepared from an hydrosol precursor. Pseudo-ID composites were prepared according to a sol impregnations/calcination/hot-pressing route. Chemical and microstructural characterizations of the fiber/matrix interfacial area were conducted by mean of TEM/EELS and AES analyses. The efficiency of BN as a coupling interphase for this particular composite system was successfully demonstrated through tensile tests performed on either as-processed or aged specimens (100 hours at 1000 deg C in air or under argon). In addition, composites maintained in air at 600 deg C, 800 deg C and 900 deg C while simultaneously loaded did not fail after 150 hours or more. Thus, a BN interphase appeared to be compatible with an oxidizing environment (i.e. the oxide matrix and/or air from 600 to 1000 deg C) and should therefore successfully replace the usual carbon interphase at least for use at medium temperatures. (author)

  10. Characterization of Ceramic Material Produced From a Cold Crucible Induction Melter Test

    Energy Technology Data Exchange (ETDEWEB)

    Amoroso, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Marra, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-04-30

    This report summarizes the results from characterization of samples from a melt processed surrogate ceramic waste form. Completed in October of 2014, the first scaled proof of principle cold crucible induction melter (CCIM) test was conducted to process a Fe-hollandite-rich titanate ceramic for treatment of high level nuclear waste. X-ray diffraction, electron microscopy, inductively coupled plasma-atomic emission spectroscopy (and inductively coupled plasma-mass spectroscopy for Cs), and product consistency tests were used to characterize the CCIM material produced. Core samples at various radial locations from the center of the CCIM were taken. These samples were also sectioned and analyzed vertically. Together, the various samples were intended to provide an indication of the homogeneity throughout the CCIM with respect to phase assemblage, chemical composition, and chemical durability. Characterization analyses confirmed that a crystalline ceramic with desirable phase assemblage was produced from a melt using a CCIM. Hollandite and zirconolite were identified in addition to possible highly-substituted pyrochlore and perovskite. Minor phases rich in Fe, Al, or Cs were also identified. Remarkably only minor differences were observed vertically or radially in the CCIM material with respect to chemical composition, phase assemblage, and durability. This recent CCIM test and the resulting characterization in conjunction with demonstrated compositional improvements support continuation of CCIM testing with an improved feed composition and improved melter system.

  11. Recent developments in transparent spinel ceramic and composite windows

    Science.gov (United States)

    Bayya, Shyam; Villalobos, Guillermo; Kim, Woohong; Sanghera, Jas; Chin, Geoff; Hunt, Michael; Sadowski, Bryan; Miklos, Fritz; Aggarwal, Ishwar

    2013-09-01

    The U.S. Naval Research Laboratory has pioneered the development of sintering processes for making highly transparent optical ceramics. For example, we have demonstrated the fabrication of record low absorption loss spinel as an exit window for High Energy Laser systems and rare earth doped Y2O3 and Lu2O3 for solid-state ceramic lasers. We have also developed thick spinel windows for submarine photonic masts and predicted the performance of an imaging system using testing and modeling. More recently, we have developed a novel approach of hot pressing where a transparent ceramic is produced in the net shape without requiring post polishing. This technology will result in significant cost savings associated with polishing the final optical element. We are also developing motheye structures on spinel surface to provide rugged anti-reflective solutions. We had earlier identified a Barium GalloGermanate (BGG) glass with matching index and expansion coefficient to spinel. We had demonstrated fabrication of a laminated dome for the Joint Air to Ground Missile (JAGM) program and the technology was transitioned to industry. We have pushed this technology further by developing a BGG glass - spinel ceramic transparent micro-composite, which can be processed well below spinel sintering temperatures. To address the relatively lower strength of BGG glass compared with spinel, we developed an ion-exchange process and achieved strengths up to 450 MPa. This paper gives a summary of our recent findings.

  12. Numerical study of internal load transfer in metal/ceramic composites based on freeze-cast ceramic preforms and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Sinchuk, Yuriy [Institute of Engineering Mechanics, Karlsruhe Institute of Technology, Kaiserstr. 10, 76131 Karlsruhe (Germany); Roy, Siddhartha, E-mail: siddhartha.roy@kennametal.com [Institute for Applied Materials, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe (Germany); Gibmeier, Jens [Institute for Applied Materials, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe (Germany); Piat, Romana [Institute of Engineering Mechanics, Karlsruhe Institute of Technology, Kaiserstr. 10, 76131 Karlsruhe (Germany); Wanner, Alexander [Institute for Applied Materials, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe (Germany)

    2013-11-15

    The elastic–plastic deformation and internal load transfer in metal/ceramic composites are studied in this work both numerically and experimentally. The composite was fabricated by squeeze-casting AlSi12 melt in an open porous preform made by freeze-casting and drying of alumina suspension. Such composites exhibit a complex microstructure composed of lamellar domains. Single-domain samples were extracted from bulk material. Uniaxial compression tests were carried out parallel to the direction of the alternating metallic alloy and ceramic lamellae in the plane normal to the direction of freeze-casting. This loading mode is selected as highest load transfer occurs when loaded along the ceramic lamellae. Numerical modeling was done using the finite element method using quasi-3D microstructure based on metallographic 2D section and a modified Voigt homogenization technique assuming plastic behavior of the metallic alloy, absence of any damage and ideal interface between the phases. Internal load transfer mechanism was predicted for composites with different ceramic volume fractions. Results show that at any applied stress, as the ceramic content increases, the phase stress in alumina along the loading direction continuously decreases. Experimental validation of the numerical results is carried out by in-situ compression test along with energy dispersive synchrotron X-ray diffraction in one sample with 41 vol% ceramic. Results show that both the numerical techniques yield similar results, which match well with the experimental measurements. The ratio of the phase stress to the applied stress in alumina reaches a highest value between 2 and 2.5 up to a compressive stress of about 300 MPa. At higher applied stresses both the experimentally determined lattice microstrain and the phase stress along the loading direction in alumina decrease due to the initiation of possible damage. This study shows that the applied economic and more flexible homogenization technique is a

  13. Ceramic thin film thermocouples for SiC-based ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Wrbanek, John D., E-mail: John.D.Wrbanek@nasa.gov; Fralick, Gustave C.; Zhu Dongming

    2012-06-30

    Conductive ceramic thin film thermocouples were investigated for application to silicon carbide fiber reinforced silicon carbide ceramic matrix composite (SiC/SiC CMC) components. High temperature conductive oxides based on indium and zinc oxides were selected for testing to high temperatures in air. Sample oxide films were first sputtered-deposited on alumina substrates then on SiC/SiC CMC sample disks. Operational issues such as cold junction compensation to a 0 Degree-Sign C reference, resistivity and thermopower variations are discussed. Results show that zinc oxides have an extremely high resistance and thus increased complexity for use as a thermocouple, but thermocouples using indium oxides can achieve a strong, nearly linear response to high temperatures. - Highlights: Black-Right-Pointing-Pointer Oxide thin film thermocouples tested for SiC/SiC ceramic matrix composites (CMCs) Black-Right-Pointing-Pointer In{sub 2}O{sub 3}, N:In{sub 2}O{sub 3}, ZnO, AlZnO sputtered and tested on Al{sub 2}O{sub 3} and CMC substrates Black-Right-Pointing-Pointer ZnO, AlZnO have high resistance, complex temperature response. Black-Right-Pointing-Pointer In{sub 2}O{sub 3}, N:In{sub 2}O{sub 3} conductive at room temperature, more linear temperature response.

  14. ADVANCED CERAMIC MATERIALS FOR DENTAL APPLICATIONS SINTERED BY MICROWAVE HEATING

    OpenAIRE

    Presenda Barrera, Álvaro

    2016-01-01

    [EN] Zirconia has become a widely utilized structural ceramic material with important applications in dentistry due to its superb mechanical properties, biocompatibility, aesthetic characteristics and durability. Zirconia needs to be stabilized in the t-phase to obtain improved mechanical properties such as hardness and fracture toughness. Fully dense yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) materials are normally consolidated through the energy-intensive processing of po...

  15. Composite materials design and applications

    CERN Document Server

    Gay, Daniel; Tsai, Stephen W

    2002-01-01

    PART ONE. PRINCIPLES OF CONSTRUCTIONCOMPOSITE MATERIALS, INTEREST AND PROPERTIESWhat is Composite Material Fibers and MatrixWhat can be Made Using Composite Materials?Typical Examples of Interest on the Use of Composite MaterialsExamples on Replacing Conventional Solutions with CompositesPrincipal Physical PropertiesFABRICATION PROCESSESMolding ProcessesOther Forming ProcessesPractical Hints in the Manufacturing ProcessesPLY PROPERTIESIsotropy and AnisotropyCharacteristics of the Reinforcement-Matrix MixtureUnidirectional PlyWoven FabricsMats and Reinforced MatricesMultidimensional FabricsMetal Matrix CompositesTestsSANDWICH STRUCTURES:What is a Sandwich Structure?Simplified FlexureA Few Special AspectsFabrication and Design ProblemsNondestructive Quality ControlCONCEPTION AND DESIGNDesign of a Composite PieceThe LaminateFailure of LaminatesSizing of LaminatesJOINING AND ASSEMBLYRiveting and BoltingBondingInsertsCOMPOSITE MATERIALS AND AEROSPACE CONSTRUCTIONAircraftHelicoptersPropeller Blades for AirplanesTur...

  16. Architectural integration of energy solar collectors made with ceramic materials and suitable for the Mediterranean climate

    Directory of Open Access Journals (Sweden)

    J. Roviras

    2016-12-01

    Full Text Available The work presented here aims to demonstrate the technical, architectural and energy viability of solar thermal collectors made with ceramic materials and the Mediterranean climate suitable for the production of domestic hot water (DHW and for heating systems in buildings. The design of a ceramic shell formed by panels collectors and panels no sensors, which are part of the same building system that is capable of responding to the basic requirements of a building envelope and capture solar energy is proposed. Ceramics considerably reduced the final cost of the sensor system and offers the new system a variety of compositional and chromatic since, with reduced performance compared to a conventional metallic collector, can occupy the entire surface of front and get a high degree of architectural integration. A tool for assessing the new ceramic solar collector has been defined from a multi-criteria perspective: economic, environmental and social. The tool enables the comparison of the ceramic solar collector with solar collectors on the market under different climatic and demand conditions.

  17. Processing and properties of ceramic matrix-polymer composites for dental applications

    Science.gov (United States)

    Huang, Hsuan Yao

    The basic composite structure of natural hard tissue was used to guide the design and processing of dental restorative materials. The design incorporates the methodology of using inorganic minerals as the main structural phase reinforced with a more ductile but tougher organic phase. Ceramic-polymer composites were prepared by slip casting a porous ceramic structure, heating and chemical treating the porous preform, infiltrating with monomer and then curing. The three factors that determined the mechanical properties of alumina-polymer composites were the type of polymer used, the method of silane treatments, and the type of bond between particles in the porous preforms. Without the use of silane coupling agents, the composites were measured to have a lower strength. The composite with a more "flexible" porous alumina network had a greater ability to plastically dissipate the energy of propagating cracks. However, the aggressive nature of the alumina particles on opposing enamel requires that these alumina-polymer composites have a wear compatible coating for practical application. A route to dense bioactive apatite wollastonite glass ceramics (AWGC)-polymer composites was developed. The problems associated with glass dissolution into the aqueous medium for slip casting were overcome with the use of silane. The role of heating rate and development of ceramic compact microstructure on composite properties was explored. In general, if isothermal heating was not applied, decreasing heating rate increased glass crystallinity and particle-particle fusion, but decreased pore volume. Also composite strength and fracture toughness decreased while modulus and hardness increased with decreasing heating rate. If isothermal heating was applied, glass crystallinity, pore content, and composite mechanical properties showed relatively little change regardless of the initial heating rate. The potential of AWGC-polymer composites for dental and implant applications was explored

  18. Electrostatic Assembly Preparation of High-Toughness Zirconium Diboride-Based Ceramic Composites with Enhanced Thermal Shock Resistance Performance.

    Science.gov (United States)

    Zhang, Baoxi; Zhang, Xinghong; Hong, Changqing; Qiu, Yunfeng; Zhang, Jia; Han, Jiecai; Hu, PingAn

    2016-05-11

    The central problem of using ceramic as a structural material is its brittleness, which associated with rigid covalent or ionic bonds. Whiskers or fibers of strong ceramics such as silicon carbide (SiC) or silicon nitride (Si3N4) are widely embedded in a ceramic matrix to improve the strength and toughness. The incorporation of these insulating fillers can impede the thermal flow in ceramic matrix, thus decrease its thermal shock resistance that is required in some practical applications. Here we demonstrate that the toughness and thermal shock resistance of zirconium diboride (ZrB2)/SiC composites can be improved simultaneously by introducing graphene into composites via electrostatic assembly and subsequent sintering treatment. The incorporated graphene creates weak interfaces of grain boundaries (GBs) and optimal thermal conductance paths inside composites. In comparison to pristine ZrB2-SiC composites, the toughness of (2.0%) ZrB2-SiC/graphene composites exhibited a 61% increasing (from 4.3 to 6.93 MPa·m(1/2)) after spark plasma sintering (SPS); the retained strength after thermal shock increased as high as 74.8% at 400 °C and 304.4% at 500 °C. Present work presents an important guideline for producing high-toughness ceramic-based composites with enhanced thermal shock properties.

  19. Investigation of Bio-Inspired Hybrid Materials through Polymer Infiltration of Thermal Spray Formed Ceramic Templates

    Science.gov (United States)

    Flynn, Katherine Claire

    High strength and toughness are often mutually exclusive in engineered materials. This is especially true of ceramics and polymers. Ceramics exhibit high strength and stiffness, but are brittle while polymers are flaw tolerant but prone to deformation at low stresses. Nature overcomes this restriction in materials by strategically combining brittle components with tough organics, leading to materials with both a high strength and toughness. One of the most impressive natural composites is nacre consisting of mainly a brittle mineral phase, 95vol% calcium carbonate (aragonite), and 5vol% biopolymer (a combination of proteins and polysaccahrides). Nature combines constituents with poor macroscale properties and achieves levels that surpass those expected despite being formed of mostly mineral CaCO3 tablets. Interestingly, nacreous assemblies can display a toughness 3,000 times higher than their major constituent, aragonite. Similarities have been observed between nacre and sprayed ceramics in terms of their microstructures and mechanical behavior. Both assemblies follow a design hierarchy and layered organization over several length scales. The mineral phase in nacre has evolved on the microscale and nanometer interlayers of biopolymer bond neighboring tablets. In addition, these tablets have a certain degree of waviness, nanoscale roughness, and mineral bridges thereby further enhancing linkages to one another. These inherent microstructural features significantly improve the mechanical properties of nacreous assemblies. On the other hand, sprayed ceramics are formed from micron sized splats, larger than aragonite nacreous tablets, with comparable (nanoscale) roughness, resulting from grain termination sites. Together these features of sprayed ceramics respond similarly to nacre, showing a great extent of mechanical nonlinearity and hysteresis, which is mostly absent in structural ceramics. Due to the splat-by-splat deposition process, sprayed ceramics contain a

  20. Reuse of sugarcane bagasse ash (SCBA) to produce ceramic materials.

    Science.gov (United States)

    Souza, A E; Teixeira, S R; Santos, G T A; Costa, F B; Longo, E

    2011-10-01

    Sugarcane bagasse ash (SCBA) is a residue resulting from the burning of bagasse in boilers in the sugarcane/alcohol industry. SCBA has a very high silica concentration and contains aluminum, iron, alkalis and alkaline earth oxides in smaller amounts. In this work, the properties of sintered ceramic bodies were evaluated based on the concentration of SCBA, which replaced non-plastic material. The ash was mixed (up to 60 wt%) with a clayed raw material that is used to produce roof tiles. Prismatic probes were pressed and sintered at different temperatures (up to 1200 °C). Technological tests of ceramic probes showed that the addition of ash has little influence on the ceramic properties up to 1000 °C. X-ray diffraction and thermal analysis data showed that, above this temperature the ash participates in the sintering process and in the formation of new important phases. The results reported show that the reuse of SCBA in the ceramic industry is feasible.

  1. In situ observation of mechanical damage within a SiC-SiC ceramic matrix composite

    Science.gov (United States)

    Saucedo-Mora, L.; Lowe, T.; Zhao, S.; Lee, P. D.; Mummery, P. M.; Marrow, T. J.

    2016-12-01

    SiC-SiC ceramic matrix composites are candidate materials for fuel cladding in Generation IV nuclear fission reactors and as accident tolerant fuel clad in current generation plant. Experimental methods are needed that can detect and quantify the development of mechanical damage, to support modelling and qualification tests for these critical components. In situ observations of damage development have been obtained of tensile and C-ring mechanical test specimens of a braided nuclear grade SiC-SiC ceramic composite tube, using a combination of ex situ and in situ computed X-ray tomography observation and digital volume correlation analysis. The gradual development of damage by matrix cracking and also the influence of non-uniform loading are examined.

  2. Neural network applied to elemental archaeological Marajoara ceramic compositions

    Energy Technology Data Exchange (ETDEWEB)

    Toyota, Rosimeiri G.; Munita, Casimiro S., E-mail: rosimeiritoy@yahoo.com.b, E-mail: camunita@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Boscarioli, Clodis, E-mail: boscarioli@gmail.co [Universidade Estadual do Oeste do Parana, Cascavel, PR (Brazil). Centro de Ciencias Exatas e Tecnologicas. Colegiado de Informatica; Hernandez, Emilio D.M., E-mail: boscarioli@gmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica; Neves, Eduardo G.; Demartini, Celia C., E-mail: eduardo@pq.cnpq.b [Museu de Arqueologia e Etnologia (MAE/USP), Sao Paulo, SP (Brazil)

    2009-07-01

    In the last decades several analytical techniques have been used in archaeological ceramics studies. However, instrumental neutron activation analysis, INAA, employing gamma-ray spectrometry seems to be the most suitable technique because it is a simple analytical method in its purely instrumental form. The purpose of this work was to determine the concentration of Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb, and Zn in 160 original marajoara ceramic fragments by INAA. Marajoara ceramics culture was sophisticated and well developed. This culture reached its peak during the V and XIV centuries in Marajo Island located on the Amazon River delta area in Brazil. The purpose of the quantitative data was to identify compositionally homogeneous groups within the database. Having this in mind, the data set was first converted to base-10 logarithms to compensate for the differences in magnitude between major elements and trace elements, and also to yield a closer to normal distribution for several trace elements. After that, the data were analyzed using the Mahalanobis distance and using the lambda Wilks as critical value to identify the outliers. The similarities among the samples were studied by means of cluster analysis, principal components analysis and discriminant analysis. Additional confirmation of these groups was made by using elemental concentration bivariate plots. The results showed that there were two very well defined groups in the data set. In addition, the database was studied using artificial neural network with unsupervised learning strategy known as self-organizing maps to classify the marajoara ceramics. The experiments carried out showed that self-organizing maps artificial neural network is capable of discriminating ceramic fragments like multivariate statistical methods, and, again the results showed that the database was formed by two groups. (author)

  3. SHS/PHIP of ceramic composites using ilmenite concentrate

    Energy Technology Data Exchange (ETDEWEB)

    Kholghy, M. [Yerevan State University and Isfahan University of Technology, Dept. of Materials Eng (Iran, Islamic Republic of); Kharatyan, S. [Yerevan State University, Yerevan, A. Manukyan str. 1, AM-0025 (Armenia); Edris, H., E-mail: h-edris@cc.iut.ac.i [Isfahan University of Technology, Dept. of Materials Eng. Isfahan, 8415683111 (Iran, Islamic Republic of)

    2010-07-23

    Self-propagating high-temperature synthesis (SHS) process in the mixture of ilmenite, boron carbide and aluminum combined with a pseudo hot isostatic pressing (PHIP) is used in this research to produce a compact multi-ceramic composite Al{sub 2}O{sub 3}/TiB{sub 2}/TiC with Fe as a binder. Several tests were performed to identify the optimum partial weight percent of the ilmenite, boron carbide and aluminum to produce a suitable amount of each components of the product. On the other hand, a number of tests were performed to measure the delay time, optimum compaction time and optimum compaction force to produce a compact high toughness samples. The results of phase analysis using XRD tests and microstructure using SEM and EDS show that the product is a multi-ceramic composite of the Al{sub 2}O{sub 3}/TiB{sub 2}/TiC with Fe as a binder. It was shown that there are no primary reactants in the product. In this work, the combustion characteristics (combustion wave propagation velocity and temperature) of the process, as well as density and hardness of the combustion product were measured. The fracture toughness of the product was measured using Vickers indenter and Brazilian test. This shows that the samples have a high toughness in comparison to conventional ceramics.

  4. Erosion-resistant composite material

    Science.gov (United States)

    Finch, C.B.; Tennery, V.J.; Curlee, R.M.

    A highly erosion-resistant composite material is formed of chemical vapor-deposited titanium diboride on a sintered titanium diboride-nickel substrate. This material may be suitable for use in cutting tools, coal liquefaction systems, etc.

  5. Advanced ceramic materials for next-generation nuclear applications

    Science.gov (United States)

    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

  6. Mechanical behavior of Fiber Reinforced SiC/RBSN Ceramic Matrix Composites: Theory and Experiment

    Science.gov (United States)

    1991-01-01

    AD-A235 926 NASA AVSCOM Technical Memorandum 103688 Technical Report 91-C-004 Mechanical Behavior of Fiber Reinforced SiC/RBSN Ceramic Matrix Composites : Theory... CERAMIC MATRIX COMPOSITES : THEORY AND EXPERIMENT Abhisak Chulya* Department of Civil Engineering Cleveland State University Cleveland, Ohio 44115...tough and sufficiently stable continuous fiber- reinforced ceramic matrix composites (CMC) which can survive in oxidizing environ- ments at temperatures

  7. Dielectric properties of BST/MZO ceramic composites

    Institute of Scientific and Technical Information of China (English)

    GUI JianDong; WANG Yi; DONG GuiXia; DU Jun

    2009-01-01

    Ba0.6Sr0.4TiO3/Mg1-xZnxO (MZO, x = 0, 0.05, 0.10, 0.15 and 0.20) ceramic composites were prepared by traditional ceramic processing. The crystal structure, fracture surface morphology, and dielectric properties were investigated. The samples with x = 0, 0.05 and 0.10 exhibited favorable sintering be-havior, and homogeneous diphase microstructure was obtained. Nevertheless, the microstructure of the samples with x = 0.15 and 0.20 was inhomogeneous and abnormal grain growth could be observed, and the abnormal grain growth induced the degradation of dielectric strength. The sample with x = 0.10 has relatively low dielectric loss (1.26×10-3) and the optimal FOM value (about 174).

  8. The influence of Cerafiber 10 ceramic fibre on strength properties of moulding material for investment casting technology

    Directory of Open Access Journals (Sweden)

    M. Nadolski

    2009-07-01

    Full Text Available The presented investigations have been aimed to determine strength properties of shell ceramic moulds produced on the basis of silica sol with the matrix composed of MK75 silica flour and Cerafiber 10 aluminosilicate ceramic fibre, the chemical composition of the latter being 56% SiO2 and 44% Al2O3. The sample material has been obtained by multi-layer spraying of ceramic slurry onto the pattern sets. The achieved results, concerning strength properties revealed during the controlled bending test performed by means of the four-point deflectometer, have been compared with the presented elsewhere results [16-19] for moulding material with grain or grain-fibre matrix, where TC E08 fibre produced by Thermal Ceramics (i.e. Kaowool HP-50-E-08 fibre has been applied as a matrix component.

  9. Material of Burned Coal Wastes Spoil Heaps As Source of Mullite for Ceramic Industry

    Directory of Open Access Journals (Sweden)

    Daněk Tomáš

    2015-01-01

    Full Text Available Burning or burnt out mine spoil heaps may be potential sources of materials not only for building purposes, but they may also be used in the ceramic industry. Decay of the coal mass contained in the mine spoil heaps often leads to self-ignition. As a consequence of spontaneous mine fire, which may approach 1600 °C, the surrounding waste rock undergoes thermal conversion. The temperature conditions inside the burning spoil heaps are analogous to the production conditions of refractory opening materials and fillers in rotary furnaces. The article deals with an analysis of anthropogenic porcelanites in terms of their phase composition and their possible application in the ceramic industry. The material under analysis underwent X-ray diffraction, electron microscopy and X-ray fluorescence to identify its chemistry and mineralogy. The article also proposes an enrichment method for the given material, through which a higher proportion of its useful component, mullite, may be obtained. Applying this method, approximately 60 % relatively pure separated raw material suitable for the ceramic industry may be obtained from the original material.

  10. Reliability analysis of ceramic matrix composite laminates

    Science.gov (United States)

    Thomas, David J.; Wetherhold, Robert C.

    1991-01-01

    At a macroscopic level, a composite lamina may be considered as a homogeneous orthotropic solid whose directional strengths are random variables. Incorporation of these random variable strengths into failure models, either interactive or non-interactive, allows for the evaluation of the lamina reliability under a given stress state. Using a non-interactive criterion for demonstration purposes, laminate reliabilities are calculated assuming previously established load sharing rules for the redistribution of load as the failure of laminae occur. The matrix cracking predicted by ACK theory is modeled to allow a loss of stiffness in the fiber direction. The subsequent failure in the fiber direction is controlled by a modified bundle theory. Results using this modified bundle model are compared with previous models which did not permit separate consideration of matrix cracking, as well as to results obtained from experimental data.

  11. Ablation Property of Ceramics/Carbon Fibers/Resin Novel Super-hybrid Composite

    Institute of Scientific and Technical Information of China (English)

    Jun QIU; Xiaoming CAO; Chong TIAN; Jinsong ZHANG

    2005-01-01

    A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.

  12. Durable, High Thermal Conductivity Melt Infiltrated Ceramic Composites for Turbine Engine Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Durable, creep-resistant ceramic composites are necessary to meet the increased operating temperatures targeted for advanced turbine engines. Higher operating...

  13. Experimental Study of Relationships between Ultrasonic Attenuation and Dispersion for Ceramic Matrix Composite

    Science.gov (United States)

    Naumenko, A. A.; Shcherbinin, S. A.; Makariev, D. I.; Rybyanets, A. N.

    In this paper an experimental study of different ceramic matrix composites with high elastic losses and dispersion (porous piezoceramics, composites ceramics/crystals) were carried out. Complex sets of elastic, dielectric, and piezoelectric parameters of the porous piezoceramics and ceramic matrix piezocomposites were determined by the impedance spectroscopy method using Piezoelectric Resonance Analysis software. Microstructure of polished and chipped surfaces of composite samples was observed with the optical and scanning electron microcopies. Experimental frequency dependencies of attenuation coefficients and ultrasonic velocities for different ceramic matrix composites were compared with the theoretical results obtained using general Kramers-Kronig relations between the ultrasonic attenuation and dispersion.

  14. Methods of enhancing conductivity of a polymer-ceramic composite electrolyte

    Science.gov (United States)

    Kumar, Binod (Inventor)

    2003-01-01

    Methods for enhancing conductivity of polymer-ceramic composite electrolytes are provided which include forming a polymer-ceramic composite electrolyte film by a melt casting technique and uniaxially stretching the film from about 5 to 15% in length. The polymer-ceramic composite electrolyte is also preferably annealed after stretching such that it has a room temperature conductivity of from 10.sup.-4 S cm.sup.-1 to 10.sup.-3 S cm.sup.-1. The polymer-ceramic composite electrolyte formed by the methods of the present invention may be used in lithium rechargeable batteries.

  15. Colloidal processing of Fe-based metal ceramic composites with high content of ceramic reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Escribano, J. A.; Ferrari, B.; Alvaredo, P.; Gordo, E.; Sanchez-Herencia, A. J.

    2013-07-01

    Major difficulties of processing metal-matrix composites by means of conventional powder metallurgy techniques are the lack of dispersion of the phases within the final microstructure. In this work, processing through colloidal techniques of the Fe-based metal-matrix composites, with a high content of a ceramic reinforcement (Ti(C,N) ), is presented for the first time in the literature. The colloidal approach allows a higher control of the powders packing and a better homogenization of phases since powders are mixed in a liquid medium. The chemical stability of Fe in aqueous medium determines the dispersion conditions of the mixture. The Fe slurries were formulated by optimising their zeta potential and their rheology, in order to shape bulk pieces by slip-casting. Preliminary results demonstrate the viability of this procedure, also opening new paths to the microstructural design of fully sintered Fe-based hard metal, with 50 vol. % of Ti(C,N) in its composition. (Author)

  16. Characterization on C/SiC Ceramic Matrix Composites with Novel Fiber Coatings

    Science.gov (United States)

    Petko, Jeanne; Kiser, J. Douglas; McCue, Terry; Verrilli, Michael

    2002-01-01

    Ceramic Matrix Composites (CMCs) are attractive candidate materials in the aerospace industry due to their high specific strength, low density and higher temperature capabilities. The National Aeronautics and Space Administration (NASA) is pursuing the use of CMC components in advanced Reusable Launch Vehicle (RLV) propulsion applications. Carbon fiber-reinforced silicon carbide (C/SiC) is the primary material of interest for a variety of RLV propulsion applications. These composites offer high- strength carbon fibers and a high modulus, oxidation-resistant matrix. For comparison, two types of carbon fibers were processed with novel types of interface coatings (multilayer and pseudoporous). For RLV propulsion applications, environmental durability will be critical. The coatings show promise of protecting the carbon fibers from the oxidizing environment. The strengths and microstructures of these composite materials are presented.

  17. Ceramic Fiber as a New Material%新型纤维材料——陶瓷纤维

    Institute of Scientific and Technical Information of China (English)

    王小雅; 曹云峰

    2012-01-01

    陶瓷纤维以其质轻,耐火,耐腐蚀等性能,目前已经在机械、冶金、石油和化工等行业得到了广泛的应用,随着各种其他技术的应用,各种陶瓷纤维基复合材料得到了快速的发展。根据使用功能,陶瓷纤维可以分为高温陶瓷纤维和功能陶瓷纤维,用作绝热材料,过滤材料,高温超导材料等,此外陶瓷纤维还被用于生产耐高温陶瓷纤维纸和箱板纸。文章简述了陶瓷纤维的发展,列举了陶瓷纤维的种类、制备方法、应用及发展趋势。%Ceramic fiber as a new material was widely used in all fields,because of its light weight and fire-resistant,now ceramic fiber was widely used in machinery,metallurgy,petroleum,chemical industry.With a variety of other technology,all kinds of ceramic fiber composite has been developed rapidly.According to the function,ceramic fibers can be divided into high-temperature ceramic fibers and functional ceramic fibers.It can be used as insulation materials,filter materials,high-temperature superconducting materials,etc.In addition,ceramic fiber was also used in the production of high-temperature paper and cardboard paper.This paper is a brief overview of the development of ceramic fiber,the types of ceramic fiber,the preparation methods,applications and its developing trends.

  18. Composite Materials for Structural Design.

    Science.gov (United States)

    1982-03-01

    Introduction to Composite Materials , Technomic, Westport, Connecticut, 1980, pp. 19-20, 388-401. 8. W.D. Bascom, J.L. Bitner, R.J. Moulton, and A.R. Siebert...34 Introduction to Composite Materials ", Technomic Publishing Co., pp. 8-18,(1980). [6] Beckwith, S. W., "Viscoelastic Characterization of a Nonlinear Glass

  19. Actively Cooled Ceramic Composite Nozzle Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For Next Generation Launch Vehicles (NGLV), Either a Rocket-based or Turbine-based Combined Cycle (RBCC or TBCC) engine will power the Next Generation Launch Vehicle...

  20. Composite Materials in Overhead Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

    2009-01-01

    with respect to solved and persisting known failures/problems of both mechanical and electrical nature. Major challenges related to extensive use of composite materials in an overhead line system are identified, as are possible benefits - both when using standard as well as customised composite components, e......The use of composite materials, e.g. fibreglass materials, in overhead transmission line systems is nothing new. Composite based insulators have been applied to transmission lines for over 30 years, mainly as suspension and post insulators and often as an option for special applications. Also...... towers and recently conductors based on composite materials are available at transmission levels. In this paper it is investigated which composite based solutions are available in connection with complete overhead line systems including insulators, towers and conductors. The components are reviewed...

  1. Evaluation Of Shielding Efficacy Of A Ferrite Containing Ceramic Material

    Energy Technology Data Exchange (ETDEWEB)

    Verst, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-12

    The shielding evaluation of the ferrite based Mitsuishi ceramic material has produced for several radiation sources and possible shielding sizes comparative dose attenuation measurements and simulated projections. High resolution gamma spectroscopy provided uncollided and scattered photon spectra at three energies, confirming theoretical estimates of the ceramic’s mass attenuation coefficient, μ/ρ. High level irradiation experiments were performed using Co-60, Cs-137, and Cf-252 sources to measure penetrating dose rates through steel, lead, concrete, and the provided ceramic slabs. The results were used to validate the radiation transport code MCNP6 which was then used to generate dose rate attenuation curves as a function of shielding material, thickness, and mass for photons and neutrons ranging in energy from 200 keV to 2 MeV.

  2. Minimal compliance design for metal–ceramic composites with lamellar microstructures

    DEFF Research Database (Denmark)

    Piat, R.; Sinchuk, Y.; Vasoya, M.;

    2011-01-01

    . Micromechanical models are applied for the calculation of the effective elastic properties of the composites. Optimized local lamella orientations and ceramic contents are calculated, and the difference between the initial (specimen with constant ceramic content and orientation) and the optimized designs......Metal–ceramic composites produced by melt infiltration of ceramic preforms are studied in an optimal design context. The ceramic preforms are manufactured through a process of freeze-casting of Al2O3 particle suspension. The microstructure of these composites can be presented as distributions...... of lamellar domains. With local ceramic volume fraction and lamella orientation chosen as the design variables, a minimum compliance optimization problem is solved based on topology optimization and finite element methods for metal–ceramic samples with different geometries and boundary conditions...

  3. Surface Hardness of Resin Cement Polymerized under Different Ceramic Materials

    Directory of Open Access Journals (Sweden)

    Pimmada Kesrak

    2012-01-01

    Full Text Available Objectives. To evaluate the surface hardness of two light-cured resin cements polymerized under different ceramic discs. Methods. 40 experimental groups of 2 light-cured resin cement specimens (Variolink Veneer and NX3 were prepared and polymerized under 5 different ceramic discs (IPS e.max Press HT, LT, MO, HO, and Cercon of 4 thicknesses (0.5, 1.0, 1.5, and 2.0 mm, Those directly activated of both resin cements were used as control. After light activation and 37∘C storage in an incubator, Knoop hardness measurements were obtained at the bottom. The data were analyzed with three-way ANOVA, t-test, and one-way ANOVA. Results. The KHN of NX3 was of significantly higher than that of Variolink Veneer (<0.05. The KHN of resin cement polymerized under different ceramic types and thicknesses was significant difference (<0.05. Conclusion. Resin cements polymerized under different ceramic materials and thicknesses showed statistically significant differences in KHN.

  4. Superconducting composites materials. Materiaux composites supraconducteurs

    Energy Technology Data Exchange (ETDEWEB)

    Kerjouan, P.; Boterel, F.; Lostec, J.; Bertot, J.P.; Haussonne, J.M. (Centre National d' Etudes des Telecommunications (CNET), 22 - Lannion (FR))

    1991-11-01

    The new superconductor materials with a high critical current own a large importance as well in the electronic components or in the electrotechnical devices fields. The deposit of such materials with the thick films technology is to be more and more developed in the years to come. Therefore, we tried to realize such thick films screen printed on alumina, and composed mainly of the YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} material. We first realized a composite material glass/YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, by analogy with the classical screen-printed inks where the glass ensures the bonding with the substrate. We thus realized different materials by using some different classes of glass. These materials owned a superconducting transition close to the one of the pure YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} material. We made a slurry with the most significant composite materials and binders, and screen-printed them on an alumina substrate preliminary or not coated with a diffusion barrier layer. After firing, we studied the thick films adhesion, the alumina/glass/composite material interfaces, and their superconducting properties. 8 refs.; 14 figs.; 9 tabs.

  5. Effect of Microstructure of Composite Powders on Microstructure and Properties of Microwave Sintered Alumina Matrix Ceramics

    Institute of Scientific and Technical Information of China (English)

    Hanmin Bian; Yong Yang; You Wang; Wei Tian; Haifu Jiang; Zhijuan Hu; Weimin Yu

    2013-01-01

    Two kinds of different structured alumina-titania composite powders were used to prepare alumina matrix ceramics by microwave sintering.One was powder mixture of alumina and titania at a micron-submicron level,in which fused-and-crushed alumina particles (micrometers) was clad with submicron-sized titania.The other was powder mixture of alumina and titania at nanometer-nanometer level,in which nano-sized alumina and nano-sized titania particles were homogeneously mixed by ball-milling and spray dried to prepare spherical alumina-titania composite powders.The effect of the microstructure of composite powders on microstructure and properties of microwave sintered alumina matrix ceramics were investigated.Nano-sized composite (NC) powder showed enhanced sintering behavior compared with micro-sized composite (MC) powders.The asprepared NC ceramic had much denser,finer and more homogenous microstructure than MC ceramic.The mechanical properties of NC ceramic were significantly higher than that of MC ceramic,e.g.the flexural strength,Vickers hardness and fracture toughness of NC ceramic were 85.3%,130.3% and 25.7% higher than that of MC ceramic,respectively.The improved mechanical properties of NC ceramic compared with that of MC ceramic were attributed to the enhanced densification and the finer and more homogeneous microstruc.ture through the use of the nanostructured composite powders.

  6. FEAMAC/CARES Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composites

    Science.gov (United States)

    Nemeth, Noel; Bednarcyk, Brett; Pineda, Evan; Arnold, Steven; Mital, Subodh; Murthy, Pappu; Bhatt, Ramakrishna

    2016-01-01

    Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

  7. Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composite

    Science.gov (United States)

    Nemeth, Noel; Bednarcyk, Brett; Pineda, Evan; Arnold, Steven; Mital, Subodh; Murthy, Pappu

    2015-01-01

    Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

  8. Alumina-based Ceramic Material for High-voltage Ceramic Substrate

    Directory of Open Access Journals (Sweden)

    S. R. Sangawar

    2006-04-01

    Full Text Available The paper presents the study of the particle size distribution, surface area and their effecton sintering of alumina (Al2O3 using additives such as magnesium oxide (MgO and silica (SiO2,so that the samples could be sintered to high relative density (~ 97.43 % with controlled graingrowth. However, the use of MgO along with SiO2 on Al2O3 produced the powder compactshaving high Green density, sintered density with minimum porosity to achieve high dielectricstrength ceramic material, so that material can be used for high-voltage insulator applications.

  9. Basaltic scorias from Romania - complex building material us for concrete, glazing tiles, ceramic glazes, glass ceramics, mineral wool

    Energy Technology Data Exchange (ETDEWEB)

    Marica, S.; Cetean, V. [PROCEMA S.A., Bucharest (Romania)

    2002-07-01

    The most spectacular deposit of basaltic scoria from Romania is the Heghes Hill from Racos, locality situated in the central part of country. This deposit emerged as grains of various dimensions, as volcanic ash with specific porosity up to 30% and vacuolar basaltic rocks. All types of basaltic scorias have specific vacuolar appearance, red- brick or blackish - grey coloured, scoria textures and similar chemical composition with others basalts of the world. The physical and mechanical characteristics determined included the scorias in the Heghes Hill in the following categories : light rocks (2,98 g/ dmc), porous(11,04%), similar to expanded slag, slightly absorbing rocks (3,86%), with low compression strengths (1700 daN/cmp). Basaltic scoria from Heghes is a very good row material for the manufacture of concrete, for obtain decorative cutting tiles glazing with ceramic and basaltic glazes (up to 40%) varied the range of colours and for obtaining glass ceramic, mineral wool, crushing sand for road maintenance, heat -insulating bricks and shid -proof material. (orig.)

  10. Mechanics in Composite Materials and Process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae Gil

    1993-03-15

    This book includes introduction of composite materials, stress, in-plane stiffness of laminates strain rate, ply stress, failure criterion and bending, composite materials micromechanics, composite plates and micromechanics of composite materials. It also deals with process of composite materials such as autoclave vacuum bag degassing process, connection of composite materials, filament winding process, resin transfer molding, sheet molding compound and compression molding.

  11. Evaluation of internal adaptation in ceramic and composite resin inlays by silicon replica technique.

    Science.gov (United States)

    Karakaya, S; Sengun, A; Ozer, F

    2005-06-01

    This study was aimed at investigating the internal adaptation of a ceramic (Ceramco II) and two composite resin inlay materials (SureFil and 3M Filtek Z 250) using silicon replica technique as an indicator. Forty-five standard mesial-occlusal-distal (MOD) cavities were prepared into brass moulds by using computer numerically controlled system. Inlays were prepared according to manufacturers' instructions with indirect methods. Replicas of the prepared cavities and inlays were produced with a polyvinyl siloxane material (Elite H-D). The spaces between inlays and cavities were filled by different coloured light-body polyvinyl siloxane material. Two parallel slices (mesio-distally) were obtained from the replicas with a sharp blade. Different coloured polyvinyl siloxane material thickness between cavity and inlay was measured at seven points (mesial, occlusal and distal). The data were evaluated with anova and Tukey's honestly significantly different (HSD) statistical tests. In the SureFil and Ceramco II groups, the sizes of the contraction gaps at mesial and distal gingival floors were greater than that of the occlusal marginal walls. In comparison of gap formation at occlusal regions, while the 3M composite group showed highest gap values (204.33 +/- 75.45 microm), the Ceramco II group revealed the lowest (141.17 +/- 23.66 microm) (P 0.05). In conclusion, our results showed that ceramic inlays did not confer any big advantage for internal adaptation over the composite inlays.

  12. Analytical Micromechanics Modeling Technique Developed for Ceramic Matrix Composites Analysis

    Science.gov (United States)

    Min, James B.

    2005-01-01

    Ceramic matrix composites (CMCs) promise many advantages for next-generation aerospace propulsion systems. Specifically, carbon-reinforced silicon carbide (C/SiC) CMCs enable higher operational temperatures and provide potential component weight savings by virtue of their high specific strength. These attributes may provide systemwide benefits. Higher operating temperatures lessen or eliminate the need for cooling, thereby reducing both fuel consumption and the complex hardware and plumbing required for heat management. This, in turn, lowers system weight, size, and complexity, while improving efficiency, reliability, and service life, resulting in overall lower operating costs.

  13. Fracture toughness and reliability in high-temperature structural ceramics and composites: Prospects and challenges for the 21st Century

    Indian Academy of Sciences (India)

    Sunil Dutta

    2001-04-01

    The importance of high fracture toughness and reliability in Si3N4, and SiC-based structural ceramics and ceramic matrix composites is reviewed. The potential of these ceramics and ceramic matrix composites for high temperature applications in defence and aerospace applications such as gas turbine engines, radomes, and other energy conversion hardware have been well recognized. Numerous investigations were pursued to improve fracture toughness and reliability by incorporating various reinforcements such as particulate-, whisker-, and continuous fibre into Si3N4 and SiC matrices. All toughening mechanisms, e.g. crack deflection, crack branching, crack bridging, etc essentially redistribute stresses at the crack tip and increase the energy needed to propagate a crack through the composite material, thereby resulting in improved fracture toughness and reliability. Because of flaw insensitivity, continuous fibre reinforced ceramic composite (CFCC) was found to have the highest potential for higher operating temperature and longer service conditions. However, the ceramic fibres should display sufficient high temperature strength and creep resistance at service temperatures above 1000°C. The greatest challenge to date is the development of high quality ceramic fibres with associate coatings able to maintain their high strength in oxidizing environment at high temperature. In the area of processing, critical issues are preparation of optimum matrix precursors, precursor infiltration into fibre array, and matrix densification at a temperature, where grain crystallization and fibre degradation do not occur. A broad scope of effort is required for improved processing and properties with a better understanding of all candidate composite systems.

  14. Multilayer Electroactive Polymer Composite Material Comprising Carbon Nanotubes

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2009-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  15. Preparation and Properties of Orthogonal Piezoelectric Composite Materials

    Institute of Scientific and Technical Information of China (English)

    Liu Jun; Lu Ying; Zhang Xingguo; Shen Yi; Chen Chun

    2004-01-01

    . PZT piezoelectric ceramic with La2O3, SrCO3, BaO and Sb2O5 was prepared. It has high value of the piezoelectric strain constant d33 ( -681 PC/N) and high value of-d33/d31 (2.65). Orthogonal piezoelectric composite materials was designed and prepared by PZT, DAD- 40 electric conductive adhesive and E51 epoxy resin. The OPCM shows obvious orthogonal anisotropy. The matching property of the interface between piezoelectric ceramic and polymer of OPCM relies on the defects of interface. The proper conductive mid-layer could improve the matching property of the interface.

  16. Reversibly assembled cellular composite materials.

    Science.gov (United States)

    Cheung, Kenneth C; Gershenfeld, Neil

    2013-09-13

    We introduce composite materials made by reversibly assembling a three-dimensional lattice of mass-produced carbon fiber-reinforced polymer composite parts with integrated mechanical interlocking connections. The resulting cellular composite materials can respond as an elastic solid with an extremely large measured modulus for an ultralight material (12.3 megapascals at a density of 7.2 milligrams per cubic centimeter). These materials offer a hierarchical decomposition in modeling, with bulk properties that can be predicted from component measurements and deformation modes that can be determined by the placement of part types. Because site locations are locally constrained, structures can be produced in a relative assembly process that merges desirable features of fiber composites, cellular materials, and additive manufacturing.

  17. Federal Aviation Administration (FAA airworthiness certification for ceramic matrix composite components in civil aircraft systems

    Directory of Open Access Journals (Sweden)

    Gonczy Stephen T.

    2015-01-01

    Full Text Available Ceramic matrix composites (CMCs are being designed and developed for engine and exhaust components in commercial aviation, because they offer higher temperature capabilities, weight savings, and improved durability compared to metals. The United States Federal Aviation Administration (FAA issues and enforces regulations and minimum standards covering the safe manufacture, operation, and maintenance of civil aircraft. As new materials, these ceramic composite components will have to meet the certification regulations of the FAA for “airworthiness”. The FAA certification process is defined in the Federal Aviation Regulations (Title 14 of the Code of Federal Regulations, FAA policy statements, orders, advisory circulars, technical standard orders, and FAA airworthiness directives. These regulations and documents provide the fundamental requirements and guidelines for design, testing, manufacture, quality assurance, registration, operation, inspection, maintenance, and repair of aircraft systems and parts. For metallic parts in aircraft, the FAA certification and compliance process is well-established for type and airworthiness certification, using ASTM and SAE standards, the MMPDS data handbook, and FAA advisory circulars. In a similar manner for polymer matrix composites (PMC, the PMC industry and the FAA have jointly developed and are refining parallel guidelines for polymer matrix composites (PMCs, using guidance in FAA circulars and the CMH-17 PMC handbook. These documents discuss design methods and codes, material testing, property data development, life/durability assessment, production processes, QA procedures, inspection methods, operational limits, and repairs for PMCs. For ceramic composites, the FAA and the CMC and aerospace community are working together (primarily through the CMH-17 CMC handbook to define and codify key design, production, and regulatory issues that have to be addressed in the certification of CMC components in

  18. Novel sintered ceramic materials incorporated with EAF carbon steel slag

    Science.gov (United States)

    Karayannis, V.; Ntampegliotis, K.; Lamprakopoulos, S.; Papapolymerou, G.; Spiliotis, X.

    2017-01-01

    In the present research, novel sintered clay-based ceramic materials containing electric arc furnace carbon steel slag (EAFC) as a useful admixture were developed and characterized. The environmentally safe management of steel industry waste by-products and their valorization as secondary resources into value-added materials towards circular economy have attracted much attention in the last years. EAF Carbon steel slag in particular, is generated during the manufacture of carbon steel. It is a solid residue mainly composed of rich-in- Fe, Ca and Si compounds. The experimental results show that the beneficial incorporation of lower percentages of EAFC up to 6%wt. into ceramics sintered at 950 °C is attained without significant variations in sintering behavior and physico-mechanical properties. Further heating up to 1100 °C strongly enhances the densification of the ceramic microstructures, thus reducing the porosity and strengthening their mechanical performance. On the other side, in terms of thermal insulation behavior as well as energy consumption savings and production cost alleviation, the optimum sintering temperature appears to be 950 °C.

  19. Failure of Ceramic Composites in Non-Uniform Stress Fields

    Science.gov (United States)

    Rajan, Varun P.

    Continuous-fiber ceramic matrix composites (CMCs) are of interest as hot-section components in gas turbine engines due to their refractoriness and low density relative to metallic alloys. In service, CMCs will be subjected to spatially inhomogeneous temperature and stress fields. Robust tools that enable prediction of deformation and fracture under these conditions are therefore required for component design and analysis. Such tools are presently lacking. The present work helps to address this deficiency by developing models for CMC mechanical behavior at two length scales: that of the constituents and that of the components. Problems of interest are further divided into two categories: '1-D loadings,' in which the stresses are aligned with the fiber axes, and '2-D loadings,' in which the stress state is more general. For the former class of problems, the major outstanding issue is material fracture, not deformation. A fracture criterion based on the attainment of a global load maximum is developed, which yields results for pure bending of CMCs in reasonable agreement with available experimental data. For the latter class of problems, the understanding of both the micro-scale and macro-scale behavior is relatively immature. An approach based upon analysis of a unit cell (a single fiber surrounded by a matrix jacket) is pursued. Stress fields in the constituents of the composite are estimated using analytical models, the accuracy of which is confirmed using finite element analysis. As part of a fracture mechanics analysis, these fields enable estimation of the steady-state matrix cracking stress for arbitrary in-plane loading of a unidirectional ply. While insightful at the micro-scale, unit cell models are difficult to extend to coarser scales. Instead, material deformation is typically predicted using phenomenological constitutive models. One such model for CMC laminates is investigated and found to predict material instability where none should exist. Remedies to

  20. Mechanical behaviour of new zirconia-hydroxyapatite ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, J.A.; Morejon, L. [La Habana Univ. (Cuba). Centro de Biomateriales; Martinez, S. [Barcelona Univ. (Spain). Dept. Cristallografia, Mineralogia; Ginebra, M.P.; Carlsson, N.; Fernandez, E.; Planell, J.A. [Universidad Politecnica de Cataluna, Barcelona (Spain). CREB; Clavaguera-Mora, M.T.; Rodriguez-Viejo, J. [Universitat Autonoma de Barcelona (Spain). Dept. de Fisica

    2001-07-01

    In this work a new zirconia-hydroxyapatite ceramic material was obtained by uniaxial pressing and sintering in humid environment. The powder X-ray diffraction (XRD) patterns and infrared spectra (FT-IR) showed that the hydroxyapatite (HA) is the only calcium phosphate phase present. The fracture toughness for HA with 20 wt.% of magnesia partially stabilised zirconia (Mg-PSZ) was around 2.5 times higher than those obtained for HA pure, also the highest value of bending strength (160 MPa) was obtained for material reinforced with Mg-PSZ. For the MgPSZ-HA (20%) the fracture mechanism seems to be less transgranular. (orig.)

  1. Influence of different post core materials on the color of Empress 2 full ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    GE Jing; WANG Xin-zhi; FENG Hai-lan

    2006-01-01

    Background For esthetic consideration, dentin color post core materials were normally used for all-ceramic crown restorations. However, in some cases, clinicians have to consider combining a full ceramic crown with a metal post core. Therefore, this experiment was conducted to test the esthetical possibility of applying cast metal post core in a full ceramic crown restoration.Methods The color of full ceramic crowns on gold and Nickel-Chrome post cores was compared with the color of the same crowns on tooth colored post cores. Different try-in pastes were used to imitate the influence of a composite cementation on the color of different restorative combinations. The majority of patients could not detect any color difference less than △E 1.8 between the two ceramic samples. So, △E 1.8 was taken as the objective evaluative criterion for the evaluation of color matching and patients' satisfaction.Results When the Empress 2 crown was combined with the gold alloy post core, the color of the resulting material was similar to that of a glass fiber reinforced resin post core (△E = 0.3). The gold alloy post core and the try-in paste did not show a perceptible color change in the full ceramic crowns, which indicated that the color of the crowns might not be susceptible to change between lab and clinic as well as during the process of composite cementation. Without an opaque covering the Ni-Cr post core would cause an unacceptable color effect on the crown (△E = 2.0), but with opaque covering, the color effect became more clinically satisfactory (△E=1.8).Conclusions It may be possible to apply a gold alloy post core in the Empress 2 full ceramic crown restoration when necessary. If a non-extractible Ni-Cr post core exists in the root canal, it might be possible to restore the tooth with an Empress 2 crown after coveting the labial surface of the core with one layer of opaque resin cement.

  2. DOE Automotive Composite Materials Research: Present and Future Efforts

    Energy Technology Data Exchange (ETDEWEB)

    Warren, C.D.

    1999-08-10

    One method of increasing automotive energy efficiency is through mass reduction of structural components by the incorporation of composite materials. Significant use of glass reinforced polymers as structural components could yield a 20--30% reduction in vehicle weight while the use of carbon fiber reinforced materials could yield a 40--60% reduction in mass. Specific areas of research for lightweighting automotive components are listed, along with research needs for each of these categories: (1) low mass metals; (2) polymer composites; and (3) ceramic materials.

  3. Boron-bearing species in ceramic matrix composites for long-term aerospace applications

    Science.gov (United States)

    Naslain, R.; Guette, A.; Rebillat, F.; Pailler, R.; Langlais, F.; Bourrat, X.

    2004-02-01

    Boron-bearing refractory species are introduced in non-oxide ceramic matrix fibrous composites (such as SiC/SiC composites) to improve their oxidation resistance under load at high temperatures with a view to applications in the aerospace field. B-doped pyrocarbon and hex-BN have been successfully used as interphase (instead of pure pyrocarbon) either as homogeneous or multilayered fiber coatings, to arrest and deflect matrix cracks formed under load (mechanical fuse function) and to give toughness to the materials. A self-healing multilayered matrix is designed and used in a model composite, which combines B-doped pyrocarbon mechanical fuse layers and B- and Si-bearing compound (namely B 4C and SiC) layers forming B 2O 3-based fluid healing phases when exposed to an oxidizing atmosphere. All the materials are deposited by chemical vapor infiltration. Lifetimes under tensile loading of several hundreds hours at high temperatures are reported.

  4. Understanding the deformation of ceramic materials at high strain rates.

    OpenAIRE

    Hallam, David A.

    2015-01-01

    Ceramic hardness and plasticity have been highlighted as important characteristics in ballistic performance; both of which can be measured and semi-quantified from indentation experiments, respectively. However, relatively little work has investigated the accompanying type, on-set and evolution of indentation-induced damage that may also be contributing an influential role. Pressureless sintered SiC and spark plasma sintered B4C, SiC-AlN-C and range of SiC-B4C composite samples were invest...

  5. Rugometric and microtopographic non-invasive inspection in dental-resin composites and zirconia ceramics

    Science.gov (United States)

    Fernández-Oliveras, Alicia; Costa, Manuel F. M.; Pecho, Oscar E.; Rubiño, Manuel; Pérez, María. M.

    2013-11-01

    Surface properties are essential for a complete characterization of biomaterials. In restorative dentistry, the study of the surface properties of materials meant to replace dental tissues in an irreversibly diseased tooth is important to avoid harmful changes in future treatments. We have experimentally analyzed the surface characterization parameters of two different types of dental-resin composites and pre-sintered and sintered zirconia ceramics. We studied two shades of both composite types and two sintered zirconia ceramics: colored and uncolored. Moreover, a surface treatment was applied to one specimen of each dental-resin. All the samples were submitted to rugometric and microtopographic non-invasive inspection with the MICROTOP.06.MFC laser microtopographer in order to gather meaningful statistical parameters such as the average roughness (Ra), the root-mean-square deviation (Rq), the skewness (Rsk), and the kurtosis of the surface height distribution (Rku). For a comparison of the different biomaterials, the uncertainties associated to the surface parameters were also determined. With respect to Ra and Rq, significant differences between the composite shades were found. Among the dental resins, the nanocomposite presented the highest values and, for the zirconia ceramics, the pre-sintered sample registered the lowest ones. The composite performance may have been due to cluster-formation variations. Except for the composites with the surface treatment, the sample surfaces had approximately a normal distribution of heights. The surface treatment applied to the composites increased the average roughness and moved the height distribution farther away from the normal distribution. The zirconia-sintering process resulted in higher average roughness without affecting the height distribution.

  6. Fabrication of low specific resistance ceramic carbon composites by slip casting

    Directory of Open Access Journals (Sweden)

    Rahul Kumar

    2015-09-01

    Full Text Available Ceramic carbon composites (CCCs utilize carbon as the conducting phase and can be used as resistors for high voltage electrical applications. To obtain superior mechanical properties it is desired to minimize the amount of carbon yet achieve desired electrical conductivity. Thus, electrically conducting nanosized carbon like carbon black (CB was used with the matrix materials. Uniform dispersion of CB in ceramic matrix leading to a percolating network at lowest possible volume fraction is a challenge. The present work reports colloidal processing approach to overcome these challenges. Fabrication of CCCs was done by slip casting. Two types of slurries, CB slurry and alumina–clay slurry, were made independently and mixed together at a later stage to make CCCs. Electrical, thermal and mechanical properties of the CCCs have been studied.

  7. Modelling and analysis of CVD processes in porous media for ceramic composite preparation

    NARCIS (Netherlands)

    Lin, Y.S.; Burggraaf, A.J.

    1991-01-01

    A continuum phenomenological model is presented to describe chemical vapour deposition (CVD) of solid product inside porous substrate media for the preparation of reinforced ceramic-matrix composites [by the chemical vapour infiltration (CVI) process] and ceramic membrane composites (by a modified C

  8. A Comprehensive Study on Microstructure Mechanics Relationships of Ceramic Matrix Composites

    Science.gov (United States)

    1989-12-20

    The background of this research stems from the need to understand the physical mechanisms of brittle matrix cracks in fiber reinforced ceramic matrix composites . Three...theoretical and the simulative aspects. Ceramic matrix composites , Matrix cracking stress, Specimen fabrication, Testing, Theory, Simulations, Uniaxial fiber, Fracture mechanics, Oxidation, Fiber breaks.

  9. Continuous Fiber Ceramic Composite (CFCC) Program. Inventory of federally funded CFCC R&D projects

    Energy Technology Data Exchange (ETDEWEB)

    Richlen, S. [USDOE Assistant Secretary for Energy Efficiency and Renewable Energy, Washington, DC (United States). Office of Industrial Technologies; Caton, G.M.; Karnitz, M.A.; Cox, T.D. [Oak Ridge National Lab., TN (United States); Hong, W. [Institute for Defense Analyses, Alexandria, VA (United States)

    1993-05-01

    Continuous Fiber Ceramic Composites (CFCC) are a new class of materials that are lighter, stronger, more corrosion resistant, and capable of performing at elevated temperatures. This new type of material offers the potential to meet the demands of a variety of industrial, military, and aerospace applications. The Department of Energy Office of Industrial Technologies (OIT) has a new program on CFCCs for industrial applications and this program has requested an inventory of all federal projects on CFCCs that relate to their new program. The purpose of this project is to identify all other ongoing CFCC research to avoid redundancy in the OIT Program. The inventory will be used as a basis for coordinating with the other ongoing ceramic composite projects. The inventory is divided into two main parts. The first part is concerned with CFCC supporting technologies projects and is organized by the categories listed below. (1) Composite Design; (2) Materials Characterization; (3) Test Methods; (4) Non-Destructive Evaluation; (5) Environmental Effects; (6) Mechanical Properties; (7) Database Life Prediction; (8) Fracture/Damage; and (9) Joining. The second part has information on component development, fabrication, and fiber-related projects.

  10. Damage Characterization of EBC-SiCSiC Ceramic Matrix Composites Under Imposed Thermal Gradient Testing

    Science.gov (United States)

    Appleby, Matthew P.; Morscher, Gregory N.; Zhu, Dongming

    2014-01-01

    Due to their high temperature capabilities, Ceramic Matrix Composite (CMC) components are being developed for use in hot-section aerospace engine applications. Harsh engine environments have led to the development of Environmental Barrier Coatings (EBCs) for silicon-based CMCs to further increase thermal and environmental capabilities. This study aims at understanding the damage mechanisms associated with these materials under simulated operating conditions. A high heat-flux laser testing rig capable of imposing large through-thickness thermal gradients by means of controlled laser beam heating and back-side air cooling is used. Tests are performed on uncoated composites, as well as CMC substrates that have been coated with state-of-the-art ceramic EBC systems. Results show that the use of the EBCs may help increase temperature capability and creep resistance by reducing the effects of stressed oxidation and environmental degradation. Also, the ability of electrical resistance (ER) and acoustic emission (AE) measurements to monitor material condition and damage state during high temperature testing is shown; suggesting their usefulness as a valuable health monitoring technique. Micromechanics models are used to describe the localized stress state of the composite system, which is utilized along with ER modeling concepts to develop an electromechanical model capable of characterizing material behavior.

  11. "A New Class of Creep Resistant Oxide/Oxide Ceramic Matrix Composites"

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Mohit Jain, Dr. Ganesh Skandan, Prof. Roger Cannon, Rutgers University

    2007-03-30

    Despite recent progress in the development of SiC-SiC ceramic matrix composites (CMCs), their application in industrial gas turbines for distributed energy (DE) systems has been limited. The poor oxidation resistance of the non-oxide ceramics warrants the use of envrionmental barrier coatings (EBCs), which in turn lead to issues pertaining to life expectancy of the coatings. On the other hand, oxide/oxide CMCs are potential replacements, but their use has been limited until now due to the poor creep resistance at high temperatures, particularly above 1200 oC: the lack of a creep resistant matrix has been a major limiting factor. Using yttrium aluminum garnet (YAG) as the matrix material system, we have advanced the state-of-the-art in oxide/oxide CMCs by introducing innovations in both the structure and composition of the matrix material, thereby leading to high temperature matrix creep properties not achieved until now. An array of YAG-based powders with a unique set of particle characteristics were produced in-house and sintered to full density and compressive creep data was obtained. Aided in part by the composition and the microstructure, the creep rates were found to be two orders of magnitude smaller than the most creep resistant oxide fiber available commercially. Even after accounting for porosity and a smaller matrix grain size in a practical CMC component, the YAG-based matrix material was found to creep slower than the most creep resistant oxide fiber available commercially.

  12. Thermal and destructive interrogation of ceramic matrix composites

    Science.gov (United States)

    Ojard, Greg; Doza, Douglas; Ouyang, Zhong; Angel, Paul; Smyth, Imelda; Santhosh, Unni; Ahmad, Jalees; Gowayed, Yasser

    2015-03-01

    Ceramic matrix composites are intended for elevated temperature use and their performance at temperature must be clearly understood as insertion efforts are to be realized. Most efforts to understand ceramic matrix composites at temperature are based on their lifetime at temperature under stress based on fatigue or creep testing or residual testing after some combination of temperature, stress and time. While these efforts can be insightful especially based on their mechanical performance, there is no insight into how other properties are changing with thermal exposure. To gain additional insight into oxidation behavior of CMC samples, a series of fatigue and creep samples tested at two different temperatures were non-destructively interrogated after achieving run-out conditions by multiple thermal methods and limited X-ray CT. After non-destructive analysis, residual tensile tests were undertaken at room temperature. The resulting residual properties will be compared against the non-destructive data. Analysis will be done to see if data trends can be determined and correlated to the level and duration of exposure.

  13. Material Modelling - Composite Approach

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1997-01-01

    , and internal stresses caused by drying shrinkage with experimental results reported in the literature on the mechanical behavior of mature concretes. It is then concluded that the model presented applied in general with respect to age at loading.From a stress analysis point of view the most important finding......This report is part of a research project on "Control of Early Age Cracking" - which, in turn, is part of the major research programme, "High Performance Concrete - The Contractor's Technology (HETEK)", coordinated by the Danish Road Directorate, Copenhagen, Denmark, 1997.A composite......-rheological model of concrete is presented by which consistent predictions of creep, relaxation, and internal stresses can be made from known concrete composition, age at loading, and climatic conditions. No other existing "creep prediction method" offers these possibilities in one approach.The model...

  14. Piezoelectric ceramic fibers for active fiber composites: a comparative study

    Science.gov (United States)

    Kornmann, Xavier; Huber, Christian; Elsener, Hans-Rudolf

    2003-08-01

    The morphology and the free strain performances of three different piezoelectric ceramic fibers used for the manufacture of active fiber composites (AFCs) have been investigated. The morphology of the fibers has a direct influence on the manufacture of the AFCs. Fibers with non-uniform diameters are more difficult to contact with the interdigitated electrodes and can be the cause of irreparable damages in AFCs. An indirect method requiring the use of a simple analytical model is proposed to evaluate the free strain of active fiber composites. This indirect method presents a relatively good agreement with direct free strain measurements performed with strain gages glued on both sides of an AFC. The results show a systematic difference of ca. 20 % between the indirect and the direct methods. However, the indirect method did not permit to see differences of piezoelectric performance between the types of fibers.

  15. Detecting Damage in Ceramic Matrix Composites Using Electrical Resistance

    Science.gov (United States)

    Smith, Craig E.; Gyekenyesi, Andrew

    2011-01-01

    The majority of damage in SiC/SiC ceramic matrix composites subjected to monotonic tensile loads is in the form of distributed matrix cracks. These cracks initiate near stress concentrations, such as 90 deg fiber tows or large matrix pores and continue to accumulate with additional stress until matrix crack saturation is achieved. Such damage is difficult to detect with conventional nondestructive evaluation techniques (immersion ultrasonics, x-ray, etc.). Monitoring a specimen.s electrical resistance change provides an indirect approach for monitoring matrix crack density. Sylramic-iBN fiber- reinforced SiC composites with a melt infiltrated (MI) matrix were tensile tested at room temperature. Results showed an increase in resistance of more than 500% prior to fracture, which can be detected either in situ or post-damage. A relationship between resistance change and matrix crack density was also determined.

  16. Detecting Cracks in Ceramic Matrix Composites by Electrical Resistance

    Science.gov (United States)

    Smith, Craig; Gyekenyesi, Andrew

    2011-01-01

    The majority of damage in SiC/SiC ceramic matrix composites subjected to monotonic tensile loads is in the form of distributed matrix cracks. These cracks initiate near stress concentrations, such as 90o fiber tows or large matrix pores and continue to accumulate with additional stress until matrix crack saturation is achieved. Such damage is difficult to detect with conventional nondestructive evaluation techniques (immersion ultrasonics, x-ray, etc.). Monitoring a specimen.s electrical resistance change provides an indirect approach for monitoring matrix crack density. Sylramic-iBN fiber- reinforced SiC composites with a melt infiltrated (MI) matrix were tensile tested at room temperature. Results showed an increase in resistance of more than 500% prior to fracture, which can be detected either in situ or post-damage. A relationship between resistance change and matrix crack density was also determined.

  17. Ceramic Composite Mechanical Fastener System for High-Temperature Structural Assemblies Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Under Phase I, the feasibility of a novel thermal stress-free ceramic composite mechanical fastener system suitable for assembly of high-temperature composite...

  18. Assessing the static behavior of hybrid CNT-metal-ceramic composite plates

    Directory of Open Access Journals (Sweden)

    M. A. R. Loja

    2016-07-01

    Full Text Available Functionally graded materials are commonly particulate composites characterized by a varying spatial distribution of the inclusion particles. Because of this, these materials possess a great suitability potential concerning to material properties, which can be very useful to achieve specified structural behaviors. Significant features of these materials are related to their thermal barrier properties especially when ceramic materials are involved, and to the mitigation of abrupt stresses transitions, typically found in laminates. From the manufacturing point of view as well as from the computational perspective, these materials can be thought as effectively having a continuous variation of their constituent phases and consequently their properties, or by resulting from the stacking of a specified number of layers, each having constant properties. This work presents a set of parametric studies aiming to characterize the static response of hybrid functionally graded plates, concerning to their transverse displacement profile and stresses distributions. To this purpose, one considers parameters such as different ceramic materials, plates’ aspect ratio, continuous or discrete variation of phase’s mixture through thickness, the carbon nanotubes (CNT weight fraction contents and the type of nanotubes. The results obtained are discussed and conclusions are drawn.

  19. Electrospun ceramic fibers: Composition, structure and the fate of precursors

    Energy Technology Data Exchange (ETDEWEB)

    Tuttle, R.W.; Chowdury, A. [Department of Physics, Ayer Hall, 302 Buchtel Common, University of Akron, Akron, OH 44325-4001 (United States); Bender, E.T. [Department of Chemistry, Knight Chemical Laboratory, 302 Buchtel Common, University of Akron, Akron, OH 44325-3601 (United States); Ramsier, R.D. [Department of Physics, Ayer Hall, 302 Buchtel Common, University of Akron, Akron, OH 44325-4001 (United States); Department of Chemistry, Knight Chemical Laboratory, 302 Buchtel Common, University of Akron, Akron, OH 44325-3601 (United States); Institute for Teaching and Learning, Leigh Hall, 302 Buchtel Common, University of Akron, Akron, OH 44325-6236 (United States)], E-mail: rex@uakron.edu; Rapp, J.L.; Espe, M.P. [Department of Chemistry, Knight Chemical Laboratory, 302 Buchtel Common, University of Akron, Akron, OH 44325-3601 (United States)

    2008-06-15

    Fibers are electrospun from aluminum acetate/polymer mixtures and characterized by an array of techniques before and after annealing at 1200 deg.C. We demonstrate that sodium and boron present in the initial starting materials as adducts and stabilizers remain incorporated into the resulting fibers after annealing and pyrolysis of the host polymer. The influence of these minor constituents on the surfaces of the fibers is suggested by infrared and X-ray photoelectron spectroscopic data. The presence of these species may impact potential chemical applications of small diameter ceramic fibers, such as their use as catalytic supports or for chemical decomposition.

  20. Electrospun ceramic fibers: Composition, structure and the fate of precursors

    Science.gov (United States)

    Tuttle, R. W.; Chowdury, A.; Bender, E. T.; Ramsier, R. D.; Rapp, J. L.; Espe, M. P.

    2008-06-01

    Fibers are electrospun from aluminum acetate/polymer mixtures and characterized by an array of techniques before and after annealing at 1200 °C. We demonstrate that sodium and boron present in the initial starting materials as adducts and stabilizers remain incorporated into the resulting fibers after annealing and pyrolysis of the host polymer. The influence of these minor constituents on the surfaces of the fibers is suggested by infrared and X-ray photoelectron spectroscopic data. The presence of these species may impact potential chemical applications of small diameter ceramic fibers, such as their use as catalytic supports or for chemical decomposition.

  1. Robust Joining and Assembly of Ceramic Matrix Composites for High Temperature Applications

    Science.gov (United States)

    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. Performance investigation of 1-3 piezoelectric ceramic-cement composite

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Xin, E-mail: chengxin@ujn.edu.cn [University of Jinan, School of Materials Science and Engineering, Jinan 250022 (China); Xu Dongyu, E-mail: xuy_sha@163.com [Shandong University, State Key Lab of Crystal Materials, Jinan 250100 (China); Lu Lingchao; Huang Shifeng [University of Jinan, School of Materials Science and Engineering, Jinan 250022 (China); Jiang Minhua [Shandong University, State Key Lab of Crystal Materials, Jinan 250100 (China)

    2010-05-15

    A 1-3 piezoelectric ceramic-cement composite has been fabricated using sulphoaluminate cement and lead niobium-magnesium zirconate titanate ceramics (P(MN)ZT) as matrix and functional component, respectively. The influences of piezoelectric ceramic volume fraction, aspect ratios of piezoelectric ceramic rods and temperature on the piezoelectric and dielectric properties of the composites were studied. This composite was shown to exhibit an improved electromechanical coupling coefficient with the mechanical quality factor reduced. Furthermore, the acoustic impedance of the composites could also be adjusted to match concrete structures. It has been demonstrated that by adjusting the piezoelectric ceramic volume fraction and shape parameters, the developed composite can be eventually used as sensing element in structural health monitoring.

  3. ELASTIC BEHAVIOR ANALYSIS OF 3D ANGLE-INTERLOCK WOVEN CERAMIC COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Chang Yanjun; Jiao Guiqiong; Wang Bo; Liu Wei

    2006-01-01

    A micromechanical model for elastic behavior analysis of angle-interlock woven ceramic composites is proposed in this paper. This model takes into account the actual fabric structure by considering the fiber undulation and continuity in space, the cavities between adjacent yarns and the actual cross-section geometry of the yarn. Based on the laminate theory, the elastic properties of 3D angle-interlock woven ceramic composites are predicted. Different numbers of interlaced wefts have almost the same elastic moduli. The thickness of ceramic matrix has little effect on elastic moduli. When the undulation ratio increases longitudinal modulus decreases and the other Young's moduli increase. Good agreement between theoretical predictions and experimental results demonstrates the feasibility of the proposed model in analyzing the elastic properties of3D angle-interlock woven ceramic composites. The results of this paper verify the fact that the method of analyzing polyester matrix composites is suitable for woven ceramic composites.

  4. Micromechanics Fatigue Damage Analysis Modeling for Fabric Reinforced Ceramic Matrix Composites

    Science.gov (United States)

    Min, J. B.; Xue, D.; Shi, Y.

    2013-01-01

    A micromechanics analysis modeling method was developed to analyze the damage progression and fatigue failure of fabric reinforced composite structures, especially for the brittle ceramic matrix material composites. A repeating unit cell concept of fabric reinforced composites was used to represent the global composite structure. The thermal and mechanical properties of the repeating unit cell were considered as the same as those of the global composite structure. The three-phase micromechanics, the shear-lag, and the continuum fracture mechanics models were integrated with a statistical model in the repeating unit cell to predict the progressive damages and fatigue life of the composite structures. The global structure failure was defined as the loss of loading capability of the repeating unit cell, which depends on the stiffness reduction due to material slice failures and nonlinear material properties in the repeating unit cell. The present methodology is demonstrated with the analysis results evaluated through the experimental test performed with carbon fiber reinforced silicon carbide matrix plain weave composite specimens.

  5. Preparation and microwave characterization of BaNd{sub 2-x}Sm{sub x}Ti{sub 4}O{sub 12} (0 {<=} x {<=} 2) ceramics and their effect on the temperature coefficient of dielectric constant in polytetrafluoroethylene composites

    Energy Technology Data Exchange (ETDEWEB)

    Stanly Jacob, K.; Satheesh, R. [Centre for Materials for Electronics Technology, Department of Information Technology, Ministry of Communication and Information Technology, Govt. of India, M.G. Kavu, Athani P.O., Thrissur 680771, Kerala (India); Ratheesh, R., E-mail: ratheeshr@yahoo.com [Centre for Materials for Electronics Technology, Department of Information Technology, Ministry of Communication and Information Technology, Govt. of India, M.G. Kavu, Athani P.O., Thrissur 680771, Kerala (India)

    2009-10-15

    High dielectric and temperature-stable ceramic compositions have been prepared through solid-state ceramic route. The structure and microstructure of the ceramics have been studied using powder X-ray diffraction and scanning electron microscopic techniques. The dielectric properties of well-sintered ceramics are studied in the microwave frequency region using Hakki and Coleman post-resonator technique. The samples exhibited high dielectric constant (>77), relatively high quality factor (>1500) and near zero temperature coefficient of resonant frequency. Phase pure calcined ceramic materials are incorporated in the polytetrafluoroethylene matrix through a proprietary process comprising of sigma mixing, extrusion, calendering followed by hot pressing for the fabrication of planar circuit laminates. The effect of temperature coefficient of dielectric constant of the resultant polytetrafluoroethylene/ceramic composite materials is studied with respect to compositional variation of the filler materials.

  6. Poly(borosiloxanes as precursors for carbon fiber ceramic matrix composites

    Directory of Open Access Journals (Sweden)

    Renato Luiz Siqueira

    2007-06-01

    Full Text Available Ceramic matrix composites (CMCs, constituted of a silicon boron oxycarbide (SiBCO matrix and unidirectional carbon fiber rods as a reinforcement phase, were prepared by pyrolysis of carbon fiber rods wrapped in polysiloxane (PS or poly(borosiloxane (PBS matrices. The preparation of the polymeric precursors involved hydrolysis/condensation reactions of alkoxysilanes in the presence and absence of boric acid, with B/Si atomic ratios of 0.2 and 0.5. Infrared spectra of PBS showed evidence of Si-O-B bonds at 880 cm-1, due to the incorporation of the crosslinker trigonal units of BO3 in the polymeric network. X ray diffraction analyses exhibited an amorphous character of the resulting polymer-derived ceramics obtained by pyrolysis up to 1000 °C under inert atmosphere. The C/SiBCO composites showed better thermal stability than the C/SiOC materials. In addition, good adhesion between the carbon fiber and the ceramic phase was observed by SEM microscopy

  7. Colour variations in graffiti-proofed ceramic materials

    Directory of Open Access Journals (Sweden)

    García Santos, A.

    2005-06-01

    Full Text Available The investigation analyses the variation of superficial properties, COLOUR and LUMINOSITY, hat the ceramic support protected by the incorporation of a protection with transparent painting undergoes, antigraffiti. The test pieces were analysed by digital procedures, obtaining quantifiable values of each ceramic sample by means of computer programs (modifications of colour taking itself as it bases the same type of ceramics without protection. In the surface of the pieces ceramics dealt with painting antigraffiti, tones different from the original ones were observed from the piece without painting. The type of painting and the material of base, obtaining itself the following results, determine this variation: - The rustic ceramics is much more susceptible to modify its characteristics of colour that the industrialists. - In both types of analysed industrial ceramics in the investigation, the variation of the tone independently took place with the same characteristics or parameters of quantification of the type of painting. - In all the analysed types of ceramics dealt with painting antigraffiti, the colour modifies its tonality tending towards the called tones «cold», violates, by the presence of blue and the loss of the red one. Before a same painting, it was observed a greater alteration of tones and luminosity in the rustic ceramics in comparison with the industrialists.

    Se analiza la variación de propiedades superficiales, COLOR Y LUMINOSIDAD, que sufre el soporte cerámico protegido por la incorporación de una protección con pintura transparente, antigraffiti. Las probetas fueron analizadas por procedimientos digitales, obteniéndose valores cuantificables de cada muestra cerámica mediante programas de ordenador (modificaciones de color, tomándose como base el mismo tipo de cerámica sin protección. En la superficie de las piezas cerámicas tratadas con pintura antigraffiti, se observaron tonos distintos a los originales de la

  8. Carbon nanotube composite materials

    Energy Technology Data Exchange (ETDEWEB)

    O' Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  9. The suitability of XRF analysis for compositional classification of archaeological ceramic fabric: A comparison with a previous NAA study

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, R. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Laboratorio de Analisis Quimico, Calle 30 no. 502, Playa, Ciudad Habana (Cuba)]. E-mail: roman.padilla@infomed.sld.cu; Espen, P. van [University of Antwerp (Belgium); Torres, P.P. Godo [Centro de Antropologia, Havana (Cuba)

    2006-02-03

    The main drawbacks of EDXRF techniques, restricting its more frequent use for the specific purpose of compositional analysis of archaeological ceramic fabric, have been the insufficient sensitivity to determine some important elements (like Cr, REE, among others), a somewhat worse precision and the inability to perform standard-less quantitative procedures in the absence of suitable certified reference materials (CRM) for ceramic fabric. This paper presents the advantages of combining two energy dispersive X-ray fluorescence methods for fast and non-destructive analysis of ceramic fabric with increased sensitivity. Selective polarized excitation using secondary targets (EDPXRF) and radioisotope excitation (R-XRF) using a {sup 241}Am source. The analytical performance of the methods was evaluated by analyzing several CRM of sediment type, and the fitness for the purpose of compositional classification was compared with that obtained by using Instrumental Neutron Activation Analysis in a previous study of Cuban aborigine pottery.

  10. Development of new ceramic materials from the waste of serpentinite and red clay; Desenvolvimento de novos materiais ceramicos a partir de residuo de serpentinito e argila vermelha

    Energy Technology Data Exchange (ETDEWEB)

    Presotto, P., E-mail: petula.presotto@gmail.com [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Mymrine, V. [Universidade Tecnologica Federal do Parana (UFTPR), Curitiba, PR (Brazil)

    2012-07-01

    The objective of this work is to develop new ceramic materials using serpentine and glass waste and clay red. The raw materials were characterized through morphological, granulometric, mineralogical and chemical analysis. Six formulations have been developed based on the serpentine and red clay, which three of the six compositions have been adjusted with the addition of residual glass. The ceramic bodies were formed by uniaxial pressing and subjected to burn in an electric oven at temperatures of 1100 ° C, 1200 ° C, 1250 ° C and 1300 ° C. The ceramic samples obtained this way were characterized according to their physical properties (specific mass and linear retraction) and the mechanical (three points bending strength). The final properties varied according to the proportions of raw materials and firing temperature. In general, the different formulations fit the standards for traditional ceramics such as tiles and ceramic blocks. (author)

  11. Validation of new ceramic materials from tungsten mining wastes. Mechanical properties; Validacion de nuevos materiales ceramicos a partir de rocas de desecho de mineria. Propiedades mecanicas

    Energy Technology Data Exchange (ETDEWEB)

    Duran Suarez, J. A.; Montoya Herrera, J.; Silva, A. P.; Peralbo Cano, R.; Castro-Gomes, J. P.

    2014-07-01

    New ceramic materials obtained from tungsten mining wastes, from region of Beira Interior in Portugal, with no commercial use, responsible for landscape and environmental problems are presented. These preshaped new ceramic products, prepared in a wide thermal range (800 degree centigrade to 1300 degree centigrade) was evaluated by mechanical test, but also was characterized the starting raw materials: tungsten wastes mining and industrial kaolin. Results, which also include a mineralogical characterization of ceramic products and morphologic evaluation of neoformed by scanning electron microscopy, show firstly, the feasibility of converting a large number of these wastes in marketable ceramics. Thanks to the experimentation carried out, the ability to generate ceramic materials is emphasized, without the presence of mineral clay, due to the particular composition of these waste of mining with content of acid, neutral and basic oxides. (Author)

  12. The effects of residual stress, viscoelastic and thermodynamic parameters on apparent fracture toughness of dental bilayer ceramic composites

    Science.gov (United States)

    Taskonak, Burak

    Bilayer dental ceramic composites used for fixed partial dentures are becoming more widely used in dental practices because of their biocompatibility, aesthetic properties, and chemical durability. However, large statistical variations in the strength of ceramics are associated with the structural flaws as a result of processing and complex stress states within the surfaces of the materials because of thermal properties of each layer. In addition, partial delaminations of the veneer layer and connector fractures of bilayer ceramic fixed partial dentures (FPDs) have been observed in a clinical study which is a part of this dissertation. Analysis of fracture surfaces of failed FPDs reveals that such fractures of the veneering ceramic are most likely caused by lateral crack growth. Global residual stresses associated with the coefficient of thermal expansion differences between core and veneering ceramics can cause lateral crack initiation. Also, rapid cooling of bilayer ceramics from the sintering temperature of the glass veneer may not allow the interfacial stresses in the viscoelastic glass to relax to equilibrium values. This can further contribute to the propagation of lateral cracks. Furthermore, local residual stresses that develop in the plastic deformation zone below sharp contact areas on the occlusal surface are another contributor to lateral crack growth. Superposition of global residual stresses and a Boussinesq stress field can incrementally increase the possibility of lateral crack growth. The long-range goals of this study are to critically analyze the lateral crack growth mechanisms associated with residual stresses, to modify residual tensile stress distributions by controlled heat treatment, and to minimize the probability of veneering ceramic fractures. Four approaches were used to accomplish these goals: (1) clinical evaluation of a bilayer ceramic fixed partial denture system; (2) fracture surface analysis of clinically failed FPDs; (3

  13. Development ceramic composites based on Al2O3, SiO2 and IG-017 additive

    Science.gov (United States)

    Kurovics, E.; Shmakova, A.; Kanev, B.; Gömze, L. A.

    2017-02-01

    Based on high purity alumina and quartz powders and IG-017 bio-original additives the authors have developed new ceramic composite materials for different industrial purposes. The main goal was to fine a material and morphological structures of high performance ceramic composites as frames for development complex materials for extreme consumptions in the future. For this the mixed powders of Al2O3 , SiO2 and IG-017 bio-original additive were uniaxially pressed at different compaction pressures into disc shapes and were sintered in electric kiln under air (1) and nitrogrn (2) atmosphere. The grain size distributions of the raw materials were determined by laser granulometry. There thermo-physical properties were also determined by derivatography. The prepared and sintered specimens were tested on geometrical sizes, microstructure and morphology by scanning electron microscopy, porosity and water absorption. In this work the authors present the results of their research and investigation.

  14. Surface treatments for repair of feldspathic, leucite - and lithium disilicate-reinforced glass ceramics using composite resin.

    Science.gov (United States)

    Neis, Christian Alencar; Albuquerque, Nadine Luísa Guimarães; Albuquerque, Ivo de Souza; Gomes, Erica Alves; Souza-Filho, Celso Bernardo de; Feitosa, Victor Pinheiro; Spazzin, Aloisio Oro; Bacchi, Atais

    2015-01-01

    The aim of this study was to evaluate the efficacy of different surface conditioning methods on the microtensile bond strength of a restorative composite repair in three types of dental ceramics: lithium disilicate-reinforced, leucite-reinforced and feldspathic. Twelve blocks were sintered for each type of ceramic (n=3) and stored for 3 months in distilled water at 37 °C. The bonding surface of ceramics was abraded with 600-grit SiC paper. Surface treatments for each ceramic were: GC (control) - none; GDB - diamond bur #30 µm; GHF - hydrofluoric acid (10%); GT- tribochemical silica coating (45-μm size particles). Treatments were followed by cleaning with phosphoric acid 37% for 20 s + silane + adhesive. The composite resin was used as restorative material. After repair, samples were subjected to thermocycled ageing (10,000 cycles between 5 °C and 55 °C for 30 s). Thereafter, the samples were sectioned into 1.0 mm2 sticks and tested for microtensile bond strength with 0.5 mm/min crosshead speed. Data were compared by two-way ANOVA and Tukey's test (α=0.05). The superficial wear with diamond bur proved to be suitable for feldspathic porcelain and for leucite-reinforced glass ceramic while hydrofluoric acid-etching is indicated for repairs in lithium disilicate-reinforced ceramic; tribochemical silica coating is applicable to leucite-reinforced ceramic. Predominance of adhesive failures was observed (>85% in all groups). In conclusion, the success of surface treatments depends on the type of ceramic to be repaired.

  15. New ceramic material specially designed to optimise the output of the heating systems; Nuevo material ceramico disenado especificamente para optimizar el rendimiento de los sistemas de calefaccion

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    This article sets out the main features of Dual Kherr, its development and uses. Dual Kherr(reg.) is a ceramic composite based on porcelain clay. It has been specially designed to work as a storage heater and a radiant heating system. Jointly developed by the R and D departments of both companies, PAMESA and CLIMASTAR, this new material optimises the output of any heating system and it has been specially conceived to save energy. It is a great revolution, mainly due to the following: On the one hand, Dual Kherr incorporates ceramic to the heating business, opening a new and important market. On the other hand, this new material adds the aesthetics proper of the ceramic material to the design of the heating systems. It even allows the development of artistic collections. (Author)

  16. Reducing chemical vapour infiltration time for ceramic matrix composites.

    Science.gov (United States)

    Timms, L. A.; Westby, W.; Prentice, C.; Jaglin, D.; Shatwell, R. A.; Binner, J. G. P.

    2001-02-01

    Conventional routes to producing ceramic matrix composites (CMCs) require the use of high temperatures to sinter the individual ceramic particles of the matrix together. Sintering temperatures are typically much higher than the upper temperature limits of the fibres. This paper details preliminary work carried out on producing a CMC via chemical vapour infiltration (CVI), a process that involves lower processing temperatures, thus avoiding fibre degradation. The CVI process has been modified and supplemented in an attempt to reduce the CVI process time and to lower the cost of this typically expensive process. To this end microwave-enhanced CVI (MECVI) has been chosen, along with two alternative pre-infiltration steps: electrophoretic infiltration and vacuum bagging. The system under investigation is based on silicon carbide fibres within a silicon carbide matrix (SiCf/SiC). The results demonstrate that both approaches result in an enhanced initial density and a consequent significant reduction in the time required for the MECVI processing step. Dual energy X-ray absorptiometry was used as a non-destructive, density evaluation technique. Initial results indicate that the presence of the SiC powder in the pre-form changes the deposition profile during the MECVI process.

  17. Development of a ceramic material to cover walls to be applied in diagnostic radiological protection; Desenvolvimento de um material ceramico para utilizacao em protecao radiologica diagnostica

    Energy Technology Data Exchange (ETDEWEB)

    Frimaio, Audrew

    2006-07-01

    This study aims to formulate a ceramic composition for wall coating seeking to contribute to the optimization of diagnosis rooms' shielding. The work was based on experimental measures of X-radiation attenuation (80 and 100 kV) using ceramic coating materials containing different ceramic bases (red, white, gres, stoneware porcelain tiles, etc). Among the appraised ceramic bases, the white gres presented better attenuation properties and it was considered the most suitable material for the targets of this work. Different formulations of white gres were studied and altered in order to obtain better attenuation properties. Simulations of ceramic compositions using gres coating were made maintaining the percentages of 12-20% clay; 6-18% kaolin; 12-25% phyllite; 8-14% quartz; 1018% feldspar; 32-40% pegmatite and 6-8% talc in the composition of the necessary raw-material. The quantitative and qualitative chemical compositions of these materials were also evaluated and the most common representative elements are SiO{sub 2}, Fe{sub 2}O{sub 3}, Al{sub 2}O{sub 3}, CaO and Ti{sub 2}O{sub 3}. Formulations containing Pb and Ba oxides were studied, considering that CaO can be replaced by PbO or BaO. The attenuation properties for X-radiation were investigated by computer simulations considering the incident and transmitted X-ray spectra for the different studied compositions and they were compared to the properties of the reference materials Pb, Ba and BaSO{sub 4} (barite). The results obtained with the simulations indicated the formulated composition of gres ceramic base that presented better attenuation properties considering the X-ray energies used in diagnosis (80, 100 and 150 kV). Ceramic plates based on the formulated compositions that presented lower percentage differences related to Pb were experimentally produced and physically tested as wall coating and protecting barrier. Properties as flexion resistance module, density, load rupture, water absorption and X

  18. Seleção de matérias-primas no desenvolvimento de formulações de massas cerâmicas Selection of raw materials in the development of ceramic bodies compositions

    Directory of Open Access Journals (Sweden)

    L. Sánchez-Muñoz

    2002-06-01

    Full Text Available A partir de argilas de uso industrial, foram estudadas por ATD, ATG, MEV e DRX as alterações mineralógicas, microestruturais e dimensionais ocorridas com o incremento da temperatura. Com os dados de absorção de água e de retração linear foram obtidos diagramas de gresificação, propondo uma metodologia de seleção de matérias-primas para aplicação a novas massas cerâmicas.Starting from clays of industrial use, the mineralogical, microestrutural and dimensional alterations for increasing temperatures were studied by Differential Thermal Analysis, Thermogravimetric Analysis, Scanning Electron Microscopy and X-Ray Diffraction. Vitrification diagrams were obtained from water absorption and linear shrinkage data, a methodology of selection of raw materials for application to new ceramic bodies being proposed.

  19. Selection of Raw Materials for the Reactive Sinterling of Zircon Porous Ceramics

    Institute of Scientific and Technical Information of China (English)

    SHENYi; ZHANGWenli; 等

    1999-01-01

    The effect of three kinds of zircon raw materials on the sinterability and properties of porous zircon ceramics have been investigated.The results have shown that all the tested fired compacts are of high porosity,However,the sintering process are different for different raw materials.The preferable selected raw materials for porous zircon ceramics were commercials zircon and quartz.

  20. Ceramic Identity Contributes to Mechanical Properties and Osteoblast Behavior on Macroporous Composite Scaffolds

    Directory of Open Access Journals (Sweden)

    J. Kent Leach

    2012-05-01

    Full Text Available Implants formed of metals, bioceramics, or polymers may provide an alternative to autografts for treating large bone defects. However, limitations to each material motivate the examination of composites to capitalize on the beneficial aspects of individual components and to address the need for conferring bioactive behavior to the polymer matrix. We hypothesized that the inclusion of different bioceramics in a ceramic-polymer composite would alter the physical properties of the implant and the cellular osteogenic response. To test this, composite scaffolds formed from poly(lactide-co-glycolide (PLG and either hydroxyapatite (HA, β-tricalcium phosphate (TCP, or bioactive glass (Bioglass 45S®, BG were fabricated, and the physical properties of each scaffold were examined. We quantified cell proliferation by DNA content, osteogenic response of human osteoblasts (NHOsts to composite scaffolds by alkaline phosphatase (ALP activity, and changes in gene expression by qPCR. Compared to BG-PLG scaffolds, HA-PLG and TCP-PLG composite scaffolds possessed greater compressive moduli. NHOsts on BG-PLG substrates exhibited higher ALP activity than those on control, HA-, or TCP-PLG scaffolds after 21 days, and cells on composites exhibited a 3-fold increase in ALP activity between 7 and 21 days versus a minimal increase on control scaffolds. Compared to cells on PLG controls, RUNX2 expression in NHOsts on composite scaffolds was lower at both 7 and 21 days, while expression of genes encoding for bone matrix proteins (COL1A1 and SPARC was higher on BG-PLG scaffolds at both time points. These data demonstrate the importance of selecting a ceramic when fabricating composites applied for bone healing.

  1. The Fabrication and Characterization of PCL/Rice Husk Derived Bioactive Glass-Ceramic Composite Scaffolds

    Directory of Open Access Journals (Sweden)

    Farnaz Naghizadeh

    2014-01-01

    Full Text Available The present study was conducted to fabricate a 3D scaffold using polycaprolactone (PCL and silicate based bioactive glass-ceramic (R-SBgC. Different concentrations of R-SBgC prepared from rice husk ash (RHA were combined with PCL to fabricate a composite scaffold using thermally induced phase separation (TIPS method. The products were then characterized using SEM and EDX. The results demonstrated that R-SBgC in PCL matrix produced a bioactive material which has highly porous structure with interconnected porosities. There appears to be a relationship between the increase in R-SBgC concentration and increased material density and compressive modulus; however, increasing R-SBgC concentration result in reduced scaffold porosity. In conclusion, it is possible to fabricate a PCL/bioactive glass-ceramic composite from processed rice husk. Varying the R-SBgC concentrations can control the properties of this material, which is useful in the development of the ideal scaffold intended for use as a bone substitute in nonload bearing sites.

  2. Composite Coatings with Ceramic Matrix Including Nanomaterials as Solid Lubricants for Oil-Less Automotive Applications

    Directory of Open Access Journals (Sweden)

    Posmyk A.

    2016-06-01

    Full Text Available The paper presents the theoretical basis of manufacturing and chosen applications of composite coatings with ceramic matrix containing nanomaterials as a solid lubricant (AHC+NL. From a theoretical point of view, in order to reduce the friction coefficient of sliding contacts, two materials are required, i.e. one with a high hardness and the other with low shear strength. In case of composite coatings AHC+NL the matrix is a very hard and wear resistant anodic oxide coating (AHC whereas the solid lubricant used is the nanomaterial (NL featuring a low shear strength such as glassy carbon nanotubes (GC. Friction coefficient of cast iron GJL-350 sliding against the coating itself is much higher (0.18-0.22 than when it slides against a composite coating (0.08-0.14. It is possible to reduce the friction due to the presence of carbon nanotubes, or metal nanowires.

  3. Microstructures and Composition of Ceramic Coatings on Aluminum Produced by Micro-Arc Oxidation

    Institute of Scientific and Technical Information of China (English)

    SHEN De-jiu; WANG Yu-lin; GU Wei-chao; XING Guang-zhong

    2004-01-01

    Microstructures and phase composition of the ceramic coatings formed on pure aluminum by heteropolar pulsed current ceramic synthesizing system for different periods were investigated by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). Results show that the amount of the discharge channels in the ceramic coating sminish while the aperture largen in the micro-arc oxidation process, and the surface of the ceramic coatingmelted and solidified in the process.XRD studies of ceramic coatings deposited for different time show that these coatings consist mainly of α-Al2 O3, γ-Al2 O3 , θ-Al2 O3 and a little amorphous phase, and phase composition of compact and porous ceramic coatings don' t have much difference but have a little change of the content of α-Al2 O3 and amorphous phase.

  4. Characterization of Waste Material Derived Willemite-Based Glass-Ceramics Doped with Erbium

    Directory of Open Access Journals (Sweden)

    G. V. Sarrigani

    2015-01-01

    Full Text Available We reported, for the first time, to the best of our knowledge, the production of erbium doped willemite-based glass-ceramic using waste material. In this work, a willemite-based glass-ceramic was prepared from waste material to obtain excellent crystallinity and then doped with trivalent erbium (Er3+ to yield ([(ZnO0.5(SLS0.5]1−x[Er2O3]x final composition where x=3 wt%. The samples were sintered at various temperatures (500–1100°C to study the effects of sintering temperatures on microstructure and physical properties of the samples. X-ray diffraction (XRD and Fourier transform infrared (FTIR were used to determine structural changes and functional groups in the samples, respectively. Field-emission scanning electron microscopy (FE-SEM equipped with energy dispersive X-ray was used to observe surface morphology and to detect presence of elements in the samples. Findings showed that average grain size of the Er3+ doped glass-ceramic sample increased as a function of the sintering temperature and the optimum temperature was 900°C.

  5. Reactive Fusion Welding for Ultra-High Temperature Ceramic Composite Joining

    Science.gov (United States)

    2015-03-16

    INTRODUCTION Zirconium diboride (ZrB2) is ceramic material belonging to the group of materials known as ultra-high temperature ceramics (UHTCs), where UHTCs...expended during the diffusion of C from the graphite spacer. This occurs as the enthalpy of fusion (Hf) and mixing (Hmix) are expected to be positive...ZrB2 Ceramics ( Contributed Oral Presentation) Authors: Derek King, Greg E. Hilmas, and William G. Fahrenholtz Plasma arc welding was used to join

  6. Topical report to Morgantown Energy Technology Center for the interfacial coatings for ceramic-matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-09

    This report summarizes the task conducted to examine various activities on interface development for ceramic-matrix composites (CMCs) intended for high-temperature applications. While several articles have been published on the subject of CMC interfaces, the purpose of this report is to describe the various ongoing efforts on interface concepts, material selection, and issues related to processing methods employed for developing interface coatings. The most exciting and new development in the field is the discovery of monazite as a potential interface material for mullite- and alumina-based composites. Monazite offers two critical properties to the CMC system; a weakly bonded layer due to its non-wetting behavior and chemical compatibility with both alumina and mullite up to very high temperatures (> 1,600 C). A description of the Department of Energy-related activities and some thoughts on processing issues, interface testing, and effects of processing on fiber strength are given.

  7. Marginal adaptation of heat-pressed glass-ceramic veneers to Class 3 composite restorations in vitro.

    Science.gov (United States)

    Christgau, M; Friedl, K H; Schmalz, G; Edelmann, K

    1999-01-01

    The aim of the present in vitro study was to compare the marginal adaptation and integrity of heat-pressed glass-ceramic veneers to adjacent class 3 composite restorations and to enamel using four dual-curing composite resin cements of different viscosity with their corresponding dentin bonding agents. Thirty-six caries-free human maxillary incisors were first restored with mesial and distal class 3 composite restorations and then prepared for facial ceramic veneers. The cavity margins of the veneers were located either in the class 3 composite restorations or in the residual enamel. Heat-pressed glass-ceramic veneers (IPS Empress) were inserted adhesively using one of the following four luting systems in nine teeth: SonoCem (SC) with EBS; Variolink Ultra (VU), Variolink High-Viscosity (VHV), and Variolink Low-Viscosity (VLV) with Syntac. The veneer margins in the region of the composite restoration and in the region apical to the composite restoration (ceramic/composite resin cement interfaces, composite resin cement/composite restoration interface, and composite resin cement/enamel interface) were evaluated before and after thermo-cycling and mechanical loading (TCML) by quantitative margin analysis under a scanning electron microscope (SEM) using an image analysis system. Furthermore, microleakage was assessed in each tooth by dye penetration after TCML. For all luting systems, SEM analysis revealed excellent marginal adaptation of the ceramic veneers to the composite restorations as well as to enamel. The median percentages of marginal gap formation were 1.1% and less before TCML and 5.1% and less after TCML. The error-rates method revealed no statistical influence of the interface or of the viscosity of the luting material. Maximal values of dye penetration showed a significantly higher microleakage at veneers cemented with VU (median: 86.4%) compared to SC (median: 13.3%). In conclusion, the present data demonstrated that existing clinically acceptable class

  8. Composite bone cements loaded with a bioactive and ferrimagnetic glass-ceramic: Leaching, bioactivity and cytocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Verné, Enrica, E-mail: enrica.verne@polito.it [Institute of Materials Physics and Engineering, Applied Science and Technology Department, Politecnico di Torino, C. so Duca degli Abruzzi 24, 10129 Torino (Italy); Bruno, Matteo [Institute of Materials Physics and Engineering, Applied Science and Technology Department, Politecnico di Torino, C. so Duca degli Abruzzi 24, 10129 Torino (Italy); Miola, Marta [Institute of Materials Physics and Engineering, Applied Science and Technology Department, Politecnico di Torino, C. so Duca degli Abruzzi 24, 10129 Torino (Italy); Department of Health Sciences, Università del Piemonte Orientale “Amedeo Avogadro”, Via Solaroli 17, 28100 Novara (Italy); Maina, Giovanni; Bianco, Carlotta [Traumatology Orthopedics and Occupational Medicine Dept., Università di Torino, Via G. Zuretti 29, 10126 Torino (Italy); Cochis, Andrea [Department of Health Sciences, Università del Piemonte Orientale “Amedeo Avogadro”, Via Solaroli 17, 28100 Novara (Italy); Rimondini, Lia [Department of Health Sciences, Università del Piemonte Orientale “Amedeo Avogadro”, Via Solaroli 17, 28100 Novara (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy)

    2015-08-01

    In this work, composite bone cements, based on a commercial polymethylmethacrylate matrix (Palamed®) loaded with ferrimagnetic bioactive glass-ceramic particles (SC45), were produced and characterized in vitro. The ferrimagnetic bioactive glass-ceramic belongs to the system SiO{sub 2}–Na{sub 2}O–CaO–P{sub 2}O{sub 5}–FeO–Fe{sub 2}O{sub 3} and contains magnetite (Fe{sub 3}O{sub 4}) crystals into a residual amorphous bioactive phase. Three different formulations (containing 10, 15 and 20 wt.% of glass-ceramic particles respectively) have been investigated. These materials are intended to be applied as bone fillers for the hyperthermic treatment of bone tumors. The morphological, compositional, calorimetric and mechanical properties of each formulation have been already discussed in a previous paper. The in vitro properties of the composite bone cements described in the present paper are related to iron ion leaching test (by graphite furnace atomic absorption spectrometer), bioactivity (i.e. the ability to stimulate the formation of a hydroxyapatite – HAp – layer on their surface after soaking in simulated body fluid SBF) and cytocompatibility toward human osteosarcoma cells (ATCC CRL-1427, Mg63). Morphological and chemical characterizations by scanning electron microscopy and energy dispersion spectrometry have been performed on the composite samples after each test. The iron release was negligible and all the tested samples showed the growth of HAp on their surface after 28 days of immersion in a simulated body fluid (SBF). Cells showed good viability, morphology, adhesion, density and the ability to develop bridge-like structures on all investigated samples. A synergistic effect between bioactivity and cell mineralization was also evidenced. - Highlights: • An in vitro biological characterization was carried out on ferromagnetic and bioactive composite cements. • No release of iron was revealed in the physiological solution. • Bioactivity tests

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

    Science.gov (United States)

    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.

  10. Economical Fabrication of Thick-Section Ceramic Matrix Composites

    Science.gov (United States)

    Babcock, Jason; Ramachandran, Gautham; Williams, Brian; Benander, Robert

    2010-01-01

    A method was developed for producing thick-section [>2 in. (approx.5 cm)], continuous fiber-reinforced ceramic matrix composites (CMCs). Ultramet-modified fiber interface coating and melt infiltration processing, developed previously for thin-section components, were used for the fabrication of CMCs that were an order of magnitude greater in thickness [up to 2.5 in. (approx.6.4 cm)]. Melt processing first involves infiltration of a fiber preform with the desired interface coating, and then with carbon to partially densify the preform. A molten refractory metal is then infiltrated and reacts with the excess carbon to form the carbide matrix without damaging the fiber reinforcement. Infiltration occurs from the inside out as the molten metal fills virtually all the available void space. Densification to 41 ksi (approx. 283 MPa) flexural strength.

  11. Internal load transfer and damage evolution in a 3D interpenetrating metal/ceramic composite

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Siddhartha, E-mail: siddhartha.roy@kit.edu [Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Gibmeier, Jens; Kostov, Vladimir; Weidenmann, Kay Andre [Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Nagel, Alwin [Hochschule Aalen, Beethovenstr. 1, 73430 Aalen (Germany); Wanner, Alexander [Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Internal load transfer and compressive damage in an interpenetrating composite is studied. Black-Right-Pointing-Pointer Unloading and reloading in tension initiates damage in alumina phase. Black-Right-Pointing-Pointer Load reversal causes Bauschinger effect in aluminium solid solution. Black-Right-Pointing-Pointer Compressive damage occurs by cracks at 45 Degree-Sign through the ceramic rich regions. - Abstract: The internal load transfer and compressive damage evolution in an interpenetrating Al{sub 2}O{sub 3}/AlSi12 composite have been studied in this work. The composite was fabricated by squeeze-casting eutectic aluminium-silicon alloy melt in a porous alumina preform. The preform was fabricated from a mixture of cellulose fibres and alumina particles via cold pressing and sintering. In an earlier work we reported the internal load transfer in the same composite material under monotonic compression and tension studied using energy dispersive synchrotron X-ray diffraction . The current work is a continuation of this earlier study, aimed at obtaining further understanding about load transfer occurring during load reversal and damage behaviour during external compression. The micromechanical load partitioning between the three phases present in the composite is studied during one load cycle starting in compression followed by unloading and reloading in tension until failure. Average strain and stress value in each phase is calculated from several diffraction planes of each phase and as a result the reported strain and stress are representative of the bulk material behaviour. The load transfer results allow identifying the occurrence of a substantial Bauschinger effect in the Al solid solution phase and progressive damage evolution within the alumina phase. In situ compression test inside a scanning electron microscope showed that failure of the composite occurred by propagation of cracks through the ceramic rich regions

  12. Reaction hot-pressing and property-composition relationships of modified sialon - boron nitride hetero-modulus ceramics

    Science.gov (United States)

    Wang, Y.; Shabalin, I. L.; Zhang, L.; Zhdanov, V. B.

    2011-10-01

    Hetero-modulus ceramics (HMC) present the combination of a ceramic matrix with inclusions of a dispersed phase with considerably lower values of Young's modulus, resulting in a material with significantly advanced properties. Densified '-Si6-xAlxOxN8-x based HMC materials, with various volume contents of low-modulus α-BN phase and modifiers such as TiN or ZrO2 in sialon matrix, were prepared by high-temperature reaction hot-pressing in nitrogen atmosphere. The pristine blend composition for reaction hot-pressing consisted of mixed fine powders of Si, Al, B, Ti nitrides and Al, Zr oxides. Statistical design of 25-2 fractional factorial and third-order simplex-grid types was used for the experimental studies to estimate the effects of some technological factors on the densification of hot-pressed products and the property-composition relationships of modified HMC materials.

  13. Characterization of ceramics materials mixed with Co3O4

    Science.gov (United States)

    Guzmán, A. F.; Landínez Téllez, D. A.; Roa-Rojas, J.; Fajardo, F.

    2014-04-01

    We have performed the preparation, structural, electrical and mechanical characterizations of ceramic materials composed of kaolinite Al2(Si2O5)(OH)4 and alumina (Al2O3) mixed with different concentrations of cobalt oxide (Co3O4). Ceramic samples were prepared from a base concentration of alumina 30% and kaolinite 70%, mixed with various concentrations of cobalt oxide in steps of 4% up to a value of 20%. The samples were sintered by the standard solid-state reaction method at a temperature of 1350 °C. In all samples with cobalt was found the presence of mullite. It was determined that alumina and cristobalite decreased when the cobalt concentration was increased due to the formation of the cobalt spinel. In order to determine the crystal structure of the samples, crystallographic analysis from X-ray diffraction experiments and also the semi-quantitative phase analysis were performed. Results were compared with theoretical parameters through the PowderCell 2.4 software. By increasing the concentration of cobalt oxide was found a significant increase in the resistance of materials to friction wear and a small decrease on the mean value of the dielectric constant. Through flexion measurements is observed the increases of the elasticity modulus by about 45% for the sample with 4% of cobalt oxide when compared with the samples without cobalt.

  14. Novel Processing of Unique Ceramic-Based Nuclear Materials and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hui Zhang; Raman P. Singh

    2008-11-30

    Advances in nuclear reactor technology and the use of gas-cooled fast reactors require the development of new materials that can operate at the higher temperatures expected in these systems. These include refractory alloys base on Nb, Zr, Ta, Mo, W, and Re; ceramics and composites such as those based on silicon carbide (SiCf-SiC); carbon-carbon composites; and advanced coatings. Besides the ability to handle higher expected temperatures, effective heat transfer between reactor componets is necessary for improved efficiency. Improving thermal conductivity of the materials used in nuclear fuels and other temperature critical components can lower the center-line fuel temperature and thereby enhance durability and reduce the risk of premature failure.

  15. Bonding Effectiveness of Luting Composites to Different CAD/CAM Materials

    OpenAIRE

    2016-01-01

    PURPOSE: To evaluate the influence of different surface treatments of six novel CAD/CAM materials on the bonding effectiveness of two luting composites. MATERIALS AND METHODS: Six different CAD/CAM materials were tested: four ceramics - Vita Mark II; IPS Empress CAD and IPS e.max CAD; Celtra Duo - one hybrid ceramic, Vita Enamic, and one composite CAD/CAM block, Lava Ultimate. A total of 60 blocks (10 per material) received various mechanical surface treatments: 1. 600-grit SiC ...

  16. Protein-based composite materials

    Directory of Open Access Journals (Sweden)

    Xiao Hu

    2012-05-01

    Full Text Available Protein-based composite biomaterials have been actively pursued as they can encompass a range of physical properties to accommodate a broader spectrum of functional requirements, such as elasticity to support diverse tissues. By optimizing molecular interfaces between structural proteins, useful composite materials can be fabricated as films, gels, particles, and fibers, as well as for electrical and optical devices. Such systems provide analogies to more traditional synthetic polymers yet with expanded utility due to the material's tunability, mechanical properties, degradability, biocompatibility, and functionalization, such as for drug delivery, biosensors, and tissue regeneration.

  17. Electromechanical coupling of 2-2 piezo-composite material

    Institute of Scientific and Technical Information of China (English)

    水永安; 薛强

    1996-01-01

    A dynamic mode) for 2-2 piezo-composite material was developed,in which the acoustic plane waves propagating along the interface were solved and their dispersion curves were obtained.By taking the resonator thickness as half a wavelength or its odd fold,the resonant frequencies of the composite transducers are in agreement with the dispersion curves.From the dynamic model the piezoelectric coupling coefficients for the thickness vibration of the composite could be obtained as a function of the composite thickness as well as the volume fraction of the ceramic phase.The results show that when the thickness vibration mode is decoupled with the lateral periodical vibration mode,the piezoelectric coupling reaches its maximum.This condition gives a maximum frequency bandwidth and a greatest piezoelectric coupling coefficient for the composite material.

  18. Surface Modification of Ceramic Materials Using Excimer Laser

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Changes of surface morphology following XeCl excimer laser irradiation were investigated for three engineering ceramic materials (Al2O3, Al2O3-SiC nanocomposite and Si3N4). Al2O3 and Al2O3-SiC nanocomposite samples exhibit a smooth rapid melt layer on the surface, and the formation of the metastable γ-Al2O3 was observed. A silicon-rich layer on the surface was formed after laser irradiation of Si3N4. The toughness K1c of the materials was measured by the indentation fracture method. After laser irradiation, the toughness of Al2O3, Al2O3-SiC nanocomposite and Si3N4 was improved to various degrees: Al2O3-SiC nanocomposite, 60% (max.); Al2O3, 40% (max.); Si3N4, 12% (max.).

  19. Kinetics mechanism of microwave sintering in ceramic materials

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the traditional sintering model incorporating the characteristic of microwave sintering, the ionic conductance diffusion mechanism in microwave sintering was studied. A flat-ball model was presented to describe the kinetics process in microwave sintering, and was applied to the sintering process of TZP and ZrO2-Al2O3 ceramics. The results indicate that the shrinkage rate of materials in microwave sintering is proportional to t2/3 and r-4/3, respectively, where t is the sintering time and r is the particle radius. Whereas, the shrinkage rate of materials in conventional sintering is proportional to sintering time t2/5. Our model suggests that microwave sintering is faster than conventional sintering, which shows a good agreement with the experimental observation in sintering process of TZP and ZrO2-Al2O3.

  20. Influence of Alumina Addition on the Optical Property of Zirconia/Alumina Composite Dental Ceramics

    Institute of Scientific and Technical Information of China (English)

    JIANG Li; LIAO Yunmao; LI Wei; WAN Qianbing; ZHAO Yongqi

    2011-01-01

    The influence of various alumina additions on the optical property of zirconia/alumina composite ceramics was investigated.The relative sintered densities,transmittances,color and the microstructure of the composite ceramics were studied.The experimental results showed that the relative sintered densities and transmittances decreased with alumina addition.The lightness increased obviously but the chroma change was small.Pure zirconia nanopowders sintered densely could obtain the relatively high transmittance,while the transmittance and the lightness of slight addition changed significantly.The zirconia/alumina composite ceramics with alumina addition less than 7.5wt% could achieve the relatively stable and reliable optical properties.

  1. Creep of fibrous composite materials

    DEFF Research Database (Denmark)

    Lilholt, Hans

    1985-01-01

    Models are presented for the creep behaviour of fibrous composite materials with aligned fibres. The models comprise both cases where the fibres remain rigid in a creeping matrix and cases where the fibres are creeping in a creeping matrix. The treatment allows for several contributions to the cr......Models are presented for the creep behaviour of fibrous composite materials with aligned fibres. The models comprise both cases where the fibres remain rigid in a creeping matrix and cases where the fibres are creeping in a creeping matrix. The treatment allows for several contributions...... such as Ni + W-fibres, high temperature materials such as Ni + Ni3Al + Cr3C2-fibres, and medium temperature materials such as Al + SiC-fibres. For the first two systems reasonable consistency is found for the models and the experiments, while for the third system too many unquantified parameters exist...

  2. Poly(vinylidene fluoride)/zinc oxide smart composite material

    Science.gov (United States)

    Öğüt, Erdem; Yördem, O. Sinan; Menceloğlu, Yusuf Z.; Papila, Melih

    2007-04-01

    This work aimed at fabrication and electromechanical characterization of a smart material system composed of electroactive polymer and ceramic materials. The idea of composite material system is on account of complementary characteristics of the polymer and ceramic for flexibility and piezoelectric activity. Our preliminary work included Polyvinylidene Fluoride (PVDF) as the flexible piezoelectric polymer, and Zinc Oxide (ZnO) as the piezoelectric ceramic brittle, but capable to respond strains without poling. Two alternative processes were investigated. The first process makes use of ZnO fibrous formation achieved by sintering PVA/zinc acetate precursor fibers via electrospinning. Highly brittle fibrous ZnO mat was dipped into a PVDF polymer solution and then pressed to form pellets. The second process employed commercial ZnO nanopowder material. The powder was mixed into a PVDF/acetone polymer solution, and the resultant paste was pressed to form pellets. The free standing composite pellets with electrodes on the top and bottom surfaces were then subjected to sinusoidal electric excitation and response was recorded using a fotonic sensor. An earlier work on electrospun PVDF fiber mats was also summarized here and the electromechanical characterization is reported.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  5. Bond strength durability of a resin composite on a reinforced ceramic using various repair systems

    NARCIS (Netherlands)

    Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Leite, Fabiola; Bottino, Marco Antonio

    2009-01-01

    Objectives. This study compared the durability of repair bond strength of a resin composite to a reinforced ceramic after three repair systems. Methods. Alumina-reinforced feldspathic ceramic blocks (Vitadur-alpha(R)) (N=30) were randomly divided into three groups according to the repair method: PR-

  6. Thermodynamic Investigation of Synthesizaing Metastable β—Sialon—Alon Composite Ceramic

    Institute of Scientific and Technical Information of China (English)

    HUANGXiangdong; LIWenchao; 等

    1999-01-01

    Based on its thermodynamic analysis ,β-Sialon-Alon metastable composite ceramic has been prepared by hot pressing sintering,XRD results indicate that the product of hot pressing singering is indeed Sialon-Alon metastable omposite ceramic ,which is in accordance with thermodynamic analysis

  7. Progressive Failure And Life Prediction of Ceramic and Textile Composites

    Science.gov (United States)

    Xue, David Y.; Shi, Yucheng; Katikala, Madhu; Johnston, William M., Jr.; Card, Michael F.

    1998-01-01

    An engineering approach to predict the fatigue life and progressive failure of multilayered composite and textile laminates is presented. Analytical models which account for matrix cracking, statistical fiber failures and nonlinear stress-strain behavior have been developed for both composites and textiles. The analysis method is based on a combined micromechanics, fracture mechanics and failure statistics analysis. Experimentally derived empirical coefficients are used to account for the interface of fiber and matrix, fiber strength, and fiber-matrix stiffness reductions. Similar approaches were applied to textiles using Repeating Unit Cells. In composite fatigue analysis, Walker's equation is applied for matrix fatigue cracking and Heywood's formulation is used for fiber strength fatigue degradation. The analysis has been compared with experiment with good agreement. Comparisons were made with Graphite-Epoxy, C/SiC and Nicalon/CAS composite materials. For textile materials, comparisons were made with triaxial braided and plain weave materials under biaxial or uniaxial tension. Fatigue predictions were compared with test data obtained from plain weave C/SiC materials tested at AS&M. Computer codes were developed to perform the analysis. Composite Progressive Failure Analysis for Laminates is contained in the code CPFail. Micromechanics Analysis for Textile Composites is contained in the code MicroTex. Both codes were adapted to run as subroutines for the finite element code ABAQUS and CPFail-ABAQUS and MicroTex-ABAQUS. Graphic user interface (GUI) was developed to connect CPFail and MicroTex with ABAQUS.

  8. Numerical Simulations of Tungsten Alloy Rods Penetration into Alumina Ceramic/Armor Steel Composite Target

    Institute of Scientific and Technical Information of China (English)

    LI Jin-zhu; HUANG Feng-lei; ZHANG Lian-sheng

    2008-01-01

    The Johnson-Holmquist constitutive ceramic model is re-implemented into the LS-DYNA3D program to simulate the penetration of long rod projectile into ceramic/armor steel composite targets.The damage evolution,fracture propagation,and spall damage in the ceramic/armor targets is represented during the simulation procedure and the accuracy of the penetration depth comparing between the simulating and experimental results is reliable with an error less than 8%.The relationship between the mass efficiency factor.differential factor and ceramic tiles thickness is given out for the penetration results with/without a cover plate.

  9. Mechanical Properties of Composite Materials

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Okayasu

    2014-10-01

    Full Text Available An examination has been made of the mechanical and failure properties of several composite materials, such as a short and a long carbon fiber reinforced plastic (short- and long-CFRP and metal based composite material. The short CFRP materials were used for a recycled CFRP which fabricated by the following process: the CFRP, consisting of epoxy resin with carbon fiber, is injected to a rectangular plate cavity after mixing with acrylonitrile butadiene styrene resin with different weight fractions of CFRP. The fatigue and ultimate tensile strength (UTS increased with increasing CFRP content. These correlations, however, break down, especially for tensile strength, as the CFPR content becomes more than 70%. Influence of sample temperature on the bending strength of the long-CFRP was investigated, and it appears that the strength slightly decreases with increasing the temperature, due to the weakness in the matrix. Broken fiber and pull-out or debonding between the fiber and matrix were related to the main failure of the short- and long-CFRP samples. Mechanical properties of metal based composite materials have been also investigated, where fiber-like high hardness CuAl2 structure is formed in aluminum matrix. Excellent mechanical properties were obtained in this alloy, e.g., the higher strength and the higher ductility, compared tothe same alloy without the fiber-like structure. There are strong anisotropic effects on the mechanical properties due to the fiber-like metal composite in a soft Al based matrix.

  10. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending December 31, 1982

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. (comp.)

    1983-05-01

    This report summarizes the activities of the Materials Sciences Program in the Metals and Ceramics Division. These activities constitute about one-fourth of the research and development conducted by the division. The major elements of the Materials Sciences Program can be grouped under the areas of (1) structural characterization, (2) high-temperature alloy studies, (3) structural ceramics, and (4) radiation effects.

  11. In Vitro Investigation of Bioactive Glass-Ceramic Composites Based on Biogenic Hydroxyapatite or Synthetic Calcium Phosphates

    Science.gov (United States)

    Pinchuk, Nataliia; Parkhomey, Oleksandr; Sych, Olena

    2017-02-01

    This in vitro investigation of the behavior of two types of calcium phosphate glass ceramics on the basis of phosphates of biogenic or synthetic origin prepared from initial mixtures with different particle size has revealed that some different factors affect the behavior, namely the phase composition of composite, fraction of open porosity, and average diameter of pore channels. It was established that the solubility of the composites on the basis of synthetic calcium phosphates and glass after 2 and 7 days contact with saline composites is the highest among the materials under study. First of all, this fact is related to the peculiarities of their phase composition, high fraction of open porosity, and high permeability. As for biogenic hydroxyapatite/glass materials, their solubility is several times lower in spite of close total porosity. The particle size of initial mixture practically does not affect the material solubility; the latter is only slightly lower for smaller particles.

  12. Effects of Environment On Creep Behavior of Nextel720/Alumina-Mullite Ceramic Composite With 45 Deg. Fiber Orientation at 1200 Deg. C

    Science.gov (United States)

    2009-03-01

    the 787 Dreamliner , scheduled for delivery in 2010, will be composites [2]. Ceramic matrix composites (CMCs), capable of maintaining excellent...appearance in commercial airplanes with the introduction of the Boeing 707 in the 1950s. Today, composites make up a large percentage of aircraft...structural components. Composites comprise 9% of the aircraft structural weight in the Boeing 777. Boeing is predicting that 50% of the material used on

  13. Creep performance of oxide ceramic fiber materials at elevated temperature in air and in steam

    Science.gov (United States)

    Armani, Clinton J.

    Structural aerospace components that operate in severe conditions, such as extreme temperatures and detrimental environments, require structural materials that have superior long-term mechanical properties and that are thermochemically stable over a broad range of service temperatures and environments. Ceramic matrix composites (CMCs) capable of excellent mechanical performance in harsh environments are prime candidates for such applications. Oxide ceramic materials have been used as constituents in CMCs. However, recent studies have shown that high-temperature mechanical performance of oxide-oxide CMCs deteriorate in a steam-rich environment. The degradation of strength at elevated temperature in steam has been attributed to the environmentally assisted subcritical crack growth in the oxide fibers. Furthermore, oxide-oxide CMCs have shown significant increases in steady-state creep rates in steam. The present research investigated the effects of steam on the high-temperature creep and monotonic tension performance of several oxide ceramic materials. Experimental facilities were designed and configured, and experimental methods were developed to explore the influence of steam on the mechanical behaviors of ceramic fiber tows and of ceramic bulk materials under temperatures in the 1100--1300°C range. The effects of steam on creep behavior of Nextel(TM)610 and Nextel(TM)720 fiber tows were examined. Creep rates at elevated temperatures in air and in steam were obtained for both types of fibers. Relationships between creep rates and applied stresses were modeled and underlying creep mechanisms were identified. For both types of fiber tows, a creep life prediction analysis was performed using linear elastic fracture mechanics and a power-law crack velocity model. These results have not been previously reported and have critical design implications for CMC components operating in steam or near the recommended design limits. Predictions were assessed and validated via

  14. Effect of Ti and Si interlayer materials on the joining of SiC ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yang Il; Park, Jung Hwan; Kim, Hyun Gil; Park, Dong Jun; Park, Jeong Yong; Kim, Weon Ju [LWR Fuel Technology Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-08-15

    SiC-based ceramic composites are currently being considered for use in fuel cladding tubes in light-water reactors. The joining of SiC ceramics in a hermetic seal is required for the development of ceramic-based fuel cladding tubes. In this study, SiC monoliths were diffusion bonded using a Ti foil interlayer and additional Si powder. In the joining process, a very low uniaxial pressure of ∼0.1 MPa was applied, so the process is applicable for joining thin-walled long tubes. The joining strength depended strongly on the type of SiC material. Reaction-bonded SiC (RB-SiC) showed a higher joining strength than sintered SiC because the diffusion reaction of Si was promoted in the former. The joining strength of sintered SiC was increased by the addition of Si at the Ti interlayer to play the role of the free Si in RB-SiC. The maximum joint strength obtained under torsional stress was ∼100 MPa. The joint interface consisted of TiSi{sub 2}, Ti{sub 3}SiC{sub 2}, and SiC phases formed by a diffusion reaction of Ti and Si.

  15. Structured Piezoelectric Composites: Materials and Applications

    NARCIS (Netherlands)

    Van den Ende, D.A.

    2012-01-01

    The piezoelectric effect, which causes a material to generate a voltage when it deforms, is very suitable for making integrated sensors, and (micro-) generators. However, conventional piezoelectric materials are either brittle ceramics or certain polymers with a low thermal stability, which limits t

  16. Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav

    Energy Technology Data Exchange (ETDEWEB)

    Blagoev, K., E-mail: kblagoev@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Grozeva, M., E-mail: margo@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Malcheva, G., E-mail: bobcheva@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Neykova, S., E-mail: sevdalinaneikova@abv.bg [National Institute of Archaeology with Museum, Bulgarian Academy of Sciences, 2 Saborna, 1000 Sofia (Bulgaria)

    2013-01-01

    The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893–972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts. - Highlights: ► LIBS, XRF and XRD analyses of medieval white-clay ceramic tiles fragments are done. ► Different elements and phases, presented in the ceramics fragments were determined. ► Differences in the tiles' raw material mineral composition are found. ► Information of the tiles' production process and the raw clay deposits is obtained.

  17. Fracture toughness of advanced alumina ceramics and alumina matrix composites used for cutting tool edges

    Directory of Open Access Journals (Sweden)

    M. Szutkowska

    2012-10-01

    Full Text Available Purpose: Specific characteristics in fracture toughness measurements of advanced alumina ceramics and alumina matrix composites with particular reference to α-Al2O3, Al2O3-ZrO2, Al2O3-ZrO2-TiC and Al2O3-Ti(C,N has been presented.Design/methodology/approach: The present study reports fracture toughness obtained by means of the conventional method and direct measurements of the Vickers crack length (DCM method of selected tool ceramics based on alumina: pure alumina, alumina-zirconia composite with unstabilized and stabilized zirconia, alumina–zirconia composite with addition of TiC and alumina–nitride-carbide titanium composite with 2wt% of zirconia. Specimens were prepared from submicro-scale trade powders. Vicker’s hardness (HV1, fracture toughness (KIC at room temperature, the indentation fracture toughness, Young’s modulus and apparent density were also evaluated. The microstructure was observed by means of scanning electron microscopy (SEM.Findings: The lowest value of KIC is revealed by pure alumina ceramics. The addition of (10 wt% unstabilized zirconia to alumina or a small amount (5 wt% of TiC to alumina–zirconia composite improve fracture toughness of these ceramics in comparison to alumina ceramics. Alumina ceramics and alumina-zirconia ceramics reveal the pronounced character of R-curve because of an increasing dependence on crack growth resistance with crack extension as opposed to the titanium carbide-nitride reinforced composite based on alumina. R-curve has not been observed for this composite.Practical implications: The results show the method of fracture toughness improvement of alumina tool ceramics.Originality/value: Taking into account the values of fracture toughness a rational use of existing ceramic tools should be expected.

  18. Possible production of ceramic tiles from marine dredging spoils alone and mixed with other waste materials.

    Science.gov (United States)

    Baruzzo, Daniela; Minichelli, Dino; Bruckner, Sergio; Fedrizzi, Lorenzo; Bachiorrini, Alessandro; Maschio, Stefano

    2006-06-30

    Dredging spoils, due to their composition could be considered a new potential source for the production of monolithic ceramics. Nevertheless, abundance of coloured oxides in these materials preclude the possibility of obtaining white products, but not that of producing ceramics with a good mechanical behaviour. As goal of the present research we have produced and studied samples using not only dredging spoils alone, but also mixtures with other waste materials such as bottom ashes from an incinerator of municipal solid waste, incinerated seawage sludge from a municipal seawage treatment plant and steelworks slag. Blending of different components was done by attrition milling. Powders were pressed into specimens which were air sintered in a muffle furnace and their shrinkage on firing was determined. Water absorption, density, strength, hardness, fracture toughness, thermal expansion coefficient of the fired bodies were measured; XRD and SEM images were also examined. The fired samples were finally tested in acidic environment in order to evaluate their elution behaviour and consequently their environmental compatibility. It is observed that, although the shrinkage on firing is too high for the production of tiles, in all the compositions studied the sintering procedure leads to fine microstructures, good mechanical properties and to a limitation of the release of many of the most hazardous metals contained in the starting powders.

  19. Influence of Material Properties on the Ballistic Performance of Ceramics for Personal Body Armour

    Directory of Open Access Journals (Sweden)

    Christian Kaufmann

    2003-01-01

    Full Text Available In support of improved personal armour development, depth of penetration tests have been conducted on four different ceramic materials including alumina, modified alumina, silicon carbide and boron carbide. These experiments consisted of impacting ceramic tiles bonded to aluminum cylinders with 0.50 caliber armour piercing projectiles. The results are presented in terms of ballistic efficiency, and the validity of using ballistic efficiency as a measure of ceramic performance was examined. In addition, the correlation between ballistic performance and ceramic material properties, such as elastic modulus, hardness, spall strength and Hugoniot Elastic Limit, has been considered.

  20. Washery wastes as a source of raw materials for ceramic products

    Energy Technology Data Exchange (ETDEWEB)

    Burmistrov, V.N.; Tambovtseva, N.A.

    1981-01-01

    The rapid expansion of the output of walling products and the exhaustion of raw material sources for brickmaking have brought to the fore the urgency of devising methods of utilizing coal-mining wastes in the production of rough ceramics, i.e., ceramic walling products, and sewage pipes. The method developed in the VNIIstrom Institute for the production of walling products from washery wastes has now been approved by the Joint Authorities Commission and recommended for commercial exploitation. However, these wastes can only be used (like the traditional clay materials) provided they are uniform in composition and properties. Significant variations lead to a lower product quality and reduced cost effectiveness. The composition and properties of washery wastes vary to an extent which depends on the composition variations in the rock over- and under-lying the coal seam, the proportions of rock included in the mined product, the production rhythm in the washery and the labor organizations at the mining, transportation, and cleaning stages. A survey of the variations in composition of the rocks over- and under-lying coal seams in the Donbas has shown that the average ashes are 88% above and 83% below the seam; the variability coefficients are comparatively low (13 and 16.3%, respectively). Correspondingly, the long-term average variability of the ash of the tailings from half the washeries is below 15%. The construction of modern washeries attached to the large pits will further reduce the variability in the ash of the washery wastes. We took samples from No. 1 and No. 2 washeries at the Cherevopets I and SW to investigate the variability of the tailings composition and properties.

  1. Gold Nanoparticles As A Modifying Agent of Ceramic-Polymer Composites

    Directory of Open Access Journals (Sweden)

    Sobczak-Kupiec A.

    2014-10-01

    Full Text Available Much effort has been invested in the development of biomaterials for the repair or replacement of hard tissue. The synthesis of composites based on mineral and organic constituents is nowadays extremely important for the development of materials for biomedical applications. In this paper we report the preparation and characterization of ceramic-polymer composites doped with gold nanoparticles. Properties and applications in medicine and dentistry of colloidal gold nanoparticles depends upon their size and shape. The influence of the presence of the metallic nanoparticles on the degradation process was investigated by pH and conductivity analyses of water filtrates. The nanocomposites were characterized with the use of X-ray Diffaction (XRD and Fourier Transformed Infrared Spectroscopy (FT-IR methods.

  2. Influence of pressure and temperature of deformation on phase composition of yttrium ceramics

    Science.gov (United States)

    Shishkova, N. V.; Malyshev, E. N.; Shepel, V. M.; Mikheenko, P. N.

    1994-07-01

    The influence of main flatting process parameters: pressure (P) and temperature (T), when obtaining conductors, on phase composition and critical properties of YBCO system ceramics placed into Al-bronze air-tight shell has been studied. It has been found that alongside with large decrease, due to plastic deformation, of the volume of superconducting (SC) phase there exist regions of the optimal combination of pressure and temperature where volume of SC phases can be ˜60...70% conserved as comparee to initial composition. The subsequent sintering of the deformed powder at 1250 K in the air-shell resulted in ˜90% restoring of the SC phase content. Zero resistance for different samples has been observed in the 80...86 K interval. Deformation scheme and power-temperature conditions as well as the material of hermetic shell used have shown the work to be perspective one in view of substitution of expensive silver for the Al-bronze.

  3. Characterisation of some Clays Used for Whiteware Ceramics I. Mineralogical composition

    Directory of Open Access Journals (Sweden)

    Marcel Benea

    2002-04-01

    Full Text Available In order to obtain a semiquantitative mineralogical composition of raw materials used for whiteware ceramics, four different clay types were analysed by X-ray diffraction. Studies were carried out by using a combination of analyses of the bulk sample, and of the fine fraction. Using a well-established pre-treatment methodology (use of chemicals, ultrasonic treatment, dispersion procedures, clay mineral concentration by centrifugation and sedimentation, oriented and random powder preparation, cation saturation, expansion/dehydration methods, 12 X-ray diffractometer traces were obtained from each sample. Based on these informations it was possible to establish the qualitative mineralogical composition, and also a semiquantitative one using peak intensities and peak area corrected by various factors. Scanning electron microscopy was also used in order to illustrate the identified mineral phases.

  4. Effect of sintering temperatures on titanium matrix composites reinforced by ceramic particles

    Energy Technology Data Exchange (ETDEWEB)

    Romero, F.; Amigo, V.; Busquets, D.; Klyatskina, E. [Mechanical and Materials Engineering Department. Polytechnical University of Valencia, Valencia (Spain)

    2005-07-01

    Titanium and titanium composites have a potential use in aerospace and biotechnology industries, and nowadays in others like sports and fashion ones. In this work composite materials, based on titanium matrix reinforced with ceramic particles, have been developed. PM route is used to obtain compact and sintered samples. TiN and TiAl powders, are milled with Ti powder in different volumetric percentages in a ball mill. These mixtures are pressed in a uniaxial press and sintered in a vacuum furnace at different temperatures between 1180 to 1220 deg. C. Porosity of samples is analysed, before and after the sintering process, by Archimedes technique and by image analysis. Mechanical properties and the reinforcement particles influence in the titanium matrix are studied by flexion test in green and sintered states, and by hardness and microhardness tests. Complimentarily, a microstructural analysis is carried out by optical and electron microscopy, and the reactivity between the reinforce particles and titanium matrix are studied. (authors)

  5. Composite materials. Volume 1: Properties, non-destructive testing, and repair

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, M.M. [United Technologies Corp., East Hartford, CT (United States)

    1997-12-31

    This book provides a practical overview of the different types, properties, applications and design implementations of the latest composite materials. It describes important composite families, including metals, ceramics, polymers and other engineered materials; shows how each type of composite may be designed, manufactured, strengthened, and repaired; introduces composite modeling techniques; and explains the major industrial applications for composites. Primary markets for this book include materials engineers and designers in aerospace, automotive and transportation industries; works managers, facilities engineers, test engineers, plant engineers, manufacturing and industrial engineers, and production managers; students in material science, mechanical engineering and metallurgy.

  6. Dielectric and piezoelectric properties of (Li, Ce) modified NaBi5Ti5O18composite ceramics

    Institute of Scientific and Technical Information of China (English)

    MA Lei; ZHAO Kun; LI Jixia; WU Qi; ZHAO Minglei; WANG Chunlei

    2009-01-01

    Nominal (Li0.5Ce0.5)x(Na0.5Bi0.5)(1-x)Na0.5Bi4.5Ti5O18 composite ceramics were fabricated using conventional solid-state reaction method. The coexistence of bismuth layer-structured phase and perovskite phase was determined in these ceramics using XRD technique. At room temperature, the x=0.11 sample showed the largest piezoelectric constant, d33, of about 26.5 pC/N and the largest electromechanical coupling factor, kt, of about 30%. Even after annealing at 500 ℃, the value of d33 was still about 19 pC/N, in x=0.08-0.11 samples. Moreover, these composite ceramics showed low temperature coefficients of dielectric constant and high electrical resistivity in the temperature region of 450-550 ℃. These results indicated that (Li, Ce) modified NaBi5Ti5O18 composite ceramics were promising piezoelectric materials for high-temperature applications.

  7. Low-Cost Innovative Hi-Temp Fiber Coating Process for Advanced Ceramic Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MATECH GSM (MG) proposes 1) to demonstrate a low-cost innovative Hi-Temp Si-doped in-situ BN fiber coating process for advanced ceramic matrix composites in order to...

  8. Mechanical properties of dispersed ceramic nanoparticles in polymer composites for orthopedic applications

    Directory of Open Access Journals (Sweden)

    Huinan Liu

    2010-04-01

    Full Text Available Huinan Liu, Thomas J WebsterDivision of Engineering, Brown University, Providence, RI, USAAbstract: Ceramic/polymer composites have been considered as third-generation orthopedic biomaterials due to their ability to closely match properties (such as surface, chemistry, biological, and mechanical of natural bone. It has already been shown that the addition of nanophase compared with conventional (or micron-scale ceramics to polymers enhances bone cell functions. However, in order to fully take advantage of the promising nanometer size effects that nanoceramics can provide when added to polymers, it is critical to uniformly disperse them in a polymer matrix. This is critical since ceramic nanoparticles inherently have a strong tendency to form larger agglomerates in a polymer matrix which may compromise their properties. Therefore, in this study, model ceramic nanoparticles, specifically titania and hydroxyapatite (HA, were dispersed in a model polymer (PLGA, poly-lactic-co-glycolic acid using high-power ultrasonic energy. The mechanical properties of the resulting PLGA composites with well-dispersed ceramic (either titania or HA nanoparticles were investigated and compared with composites with agglomerated ceramic nanoparticles. Results demonstrated that well-dispersed ceramic nanoparticles (titania or HA in PLGA improved mechanical properties compared with agglomerated ceramic nanoparticles even though the weight percentage of the ceramics was the same. Specifically, well-dispersed nanoceramics in PLGA enhanced the tensile modulus, tensile strength at yield, ultimate tensile strength, and compressive modulus compared with the more agglomerated nanoceramics in PLGA. In summary, supplemented by previous studies that demonstrated greater osteoblast (bone-forming cell functions on well-dispersed nanophase ceramics in polymers, the present study demonstrated that the combination of PLGA with well-dispersed nanoceramics enhanced mechanical properties

  9. High temperature auto-propagating synthesis of advanced ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Cao, G.; Morbidelli, M. (Cagliari Univ. (Italy). Dip. di Ingegneria Chimica e Materiali)

    1993-01-01

    This paper analyzes the modelling and experimental aspects relative to the production of advanced ceramic materials (i.e., carbides, borides and silicides of suitable transition metals) by means of high temperature auto-propagating synthesis. This process is characterized by a reaction front which, once triggered, auto-propagates itself through the reagent mix in the form of a combustion wave, taking advantage of the strong exothermic nature of the reaction itself. The analysis in this paper includes an investigation of the capability of models to accurately simulate the synthesis process. The validity of one particular model is checked by comparison with experimental results reported in literature. In addition, non-linear parametric sensitivity analysis is used to define 'a priori' suitable operating conditions which would guarantee ignition of the reagent mix and contemporaneously allow the optimization of process energy consumption.

  10. Comparison of the microstructure and composition of aboriginal ceramics, from indigenous site Caninhas, with the obtained ones in the region; Comparacao da microestrutura e da composicao de ceramicas indigenas provenientes do sitio arqueologico Caninhas, com as obtidas atualmente na regiao

    Energy Technology Data Exchange (ETDEWEB)

    Matos, C.C.; Nakano, F.P.; Taguchi, S.P.; Camargo-Vernilli, D., E-mail: cristhian@alunos.eel.usp.b [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia de Lorena. Dept. de Engenharia de Materiais; Ribeiro, R.B.; Rosa, S.J. L. [Faculdades Integradas Teresa D' Avila (FATEA), Lorena, SP (Brazil). Rede Salesianas. Dept. de Desenho Industrial

    2009-07-01

    The archaeological site of Caninhas is made of funeral and combustion structures and various objects of aboriginal daily use. These parts and fragments were safe and inventoried, constituting approximately 4000 units. The objective of this project was to analyze the microstructure and composition of archaeological ceramics, and ceramics made of argil current of the zone. The crystalline phases were identified by X-Rays Diffraction (XRD), elementary composition was obtained by X-Rays Fluorescence (XRF) and Energy Dispersive Spectrometry (EDS), and the microstructure was evaluated by Scanning Electron Microscope (SEM). Composition and microstructure of archaeological ceramics are different of current ceramics, indicating the effect of lixiviation in function of the time and the microstructural evolution due different ceramic processing. These results are valuable for the archaeological area studies, mainly for the cultural denoting which represents. The relation between some studies is basic to add knowledge: use of the ceramic materials engineering for archaeology application. (author)

  11. Bioactive ceramic-based materials with designed reactivity for bone tissue regeneration

    OpenAIRE

    Ohtsuki, Chikara; Kamitakahara, Masanobu; Miyazaki, Toshiki

    2009-01-01

    Bioactive ceramics have been used clinically to repair bone defects owing to their biological affinity to living bone; i.e. the capability of direct bonding to living bone, their so-called bioactivity. However, currently available bioactive ceramics do not satisfy every clinical application. Therefore, the development of novel design of bioactive materials is necessary. Bioactive ceramics show osteoconduction by formation of biologically active bone-like apatite through chemical reaction of t...

  12. Advanced manufacturing of ceramics for biomedical applications: Subjection methods for biocompatible materials

    OpenAIRE

    Minguella Canela, Joaquim; Cuiñas, D; Uceda, Roger; Rodríguez, J. V.; Vivancos Calvet, Joan

    2013-01-01

    The continuously growing utilization of ceramic compounds in the field of medicine, industry and aerospace, among others, imply a high degree of specialization in terms of the material properties and functionalization due to the diversity of the requirements of the ceramic parts. The necessity of lightweight final parts with suitable surface properties oriented to biomedic applications demands innovative ceramic compounds whose machining is, in many cases, considerably difficult due to the fr...

  13. A Fully Nonmetallic Gas Turbine Engine Enabled by Additive Manufacturing of Ceramic Composites. Part III; Additive Manufacturing and Characterization of Ceramic Composites

    Science.gov (United States)

    Halbig, Michael C.; Grady, Joseph E.; Singh, Mrityunjay; Ramsey, Jack; Patterson, Clark; Santelle, Tom

    2015-01-01

    This publication is the third part of a three part report of the project entitled "A Fully Nonmetallic Gas Turbine Engine Enabled by Additive Manufacturing" funded by NASA Aeronautics Research Institute (NARI). The objective of this project was to conduct additive manufacturing to produce ceramic matrix composite materials and aircraft engine components by the binder jet process. Different SiC powders with median sizes ranging from 9.3 to 53.0 microns were investigated solely and in powder blends in order to maximize powder packing. Various infiltration approaches were investigated to include polycarbosilane (SMP-10), phenolic, and liquid silicon. Single infiltrations of SMP-10 and phenolic only slightly filled in the interior. When the SMP-10 was loaded with sub-micron sized SiC powders, the infiltrant gave a much better result of filling in the interior. Silicon carbide fibers were added to the powder bed to make ceramic matrix composite materials. Microscopy showed that the fibers were well distributed with no preferred orientation on the horizontal plane and fibers in the vertical plane were at angles as much as 45deg. Secondary infiltration steps were necessary to further densify the material. Two to three extra infiltration steps of SMP-10 increased the density by 0.20 to 0.55 g/cc. However, the highest densities achieved were 2.10 to 2.15 g/cc. Mechanical tests consisting of 4 point bend tests were conducted. Samples from the two CMC panels had higher strengths and strains to failure than the samples from the two nonfiber reinforced panels. The highest strengths were from Set N with 65 vol% fiber loading which had an average strength of 66 MPa. Analysis of the fracture surfaces did not reveal pullout of the reinforcing fibers. Blunt fiber failure suggested that there was not composite behavior. The binder jet additive manufacturing method was used to also demonstrate the fabrication of turbine engine vane components of two different designs and sizes. The

  14. Nanoporous Polymer-Ceramic Composite Electrolytes for Lithium Metal Batteries

    KAUST Repository

    Tu, Zhengyuan

    2013-09-16

    A nanoporous composite material that offers the unique combination of high room-temperature ionic conductivity and high mechanical modulus is reported. When used as the separator/electrolyte in lithium batteries employing metallic lithium as anode, the material displays unprecedented cycling stability and excellent ability to prevent premature cell failure by dendrite-induced short circuits © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Design for additive manufacturing of composite materials and potential alloys: a review

    Directory of Open Access Journals (Sweden)

    Hegab Hussien A.

    2016-01-01

    Full Text Available As a first step of applying additive manufacturing (AM technology, plastic prototypes have been produced using various AM Process such as Fusion Deposition Modeling (FDM, Stereolithography (SLA and other processes. After more research and development, AM has become capable of producing complex net shaped in materials which can be used in applicable parts. These materials include metals, ceramics, and composites. Polymers and metals are considered as commercially available materials for AM processes; however, ceramics and composites are still considered under research and development. In this study, a literature review on design for AM of composite materials and potential alloys is discussed. It is investigated that polymer matrix, ceramic matrix, metal matrix, and fiber reinforced are most common composites through AM. Furthermore, Functionally Graded Materials (FGM is considered as an effective application of AM because AM offers the ability to control the composition and optimize the properties of the built part. An example of FGM through using AM technology is the missile nose cone which includes an ultra-high temperature ceramic graded to a refractory metal from outside to inside and it used for sustaining extreme external temperatures. During this work, different applications of AM on different classifications of composite materials are shown through studying of industrial objective, the importance of application, processing, results and future challenges.

  16. Ultrasonic Guided-Wave Scan System Used to Characterize Microstructure and Defects in Ceramic Composites

    Science.gov (United States)

    Roth, Don J.; Cosgriff, Laura M.; Martin, Richard E.; Verrilli, Michael J.; Bhatt, Ramakrishna T.

    2004-01-01

    Ceramic matrix composites (CMCs) are being developed for advanced aerospace propulsion applications to save weight, improve reuse capability, and increase performance. However, mechanical and environmental loads applied to CMCs can cause discrete flaws and distributed microdamage, significantly reducing desirable physical properties. Such microdamage includes fiber/matrix debonding (interface failure), matrix microcracking, fiber fracture and buckling, oxidation, and second phase formation. A recent study (ref. 1) of the durability of a C/SiC CMC discussed the requirement for improved nondestructive evaluation (NDE) methods for monitoring degradation in these materials. Distributed microdamage in CMCs has proven difficult to characterize nondestructively because of the complex microstructure and macrostructure of these materials. This year, an ultrasonic guided-wave scan system developed at the NASA Glenn Research Center was used to characterize various microstructural and flaw conditions in SiC/SiC (silicon carbide fiber in silicon carbide matrix) and C/SiC (carbon fiber in silicon carbide matrix) CMC samples.

  17. A novel BN–MAS system composite ceramics with greatly improved mechanical properties prepared by low temperature hot-pressing

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Delong; Yang, Zhihua, E-mail: zhyang@hit.edu.cn; Duan, Xiaoming; Liang, Bin; Li, Qian; Jia, Dechang, E-mail: dcjia@hit.edu.cn; Zhou, Yu

    2015-05-01

    A novel composite ceramics with excellent mechanical properties was fabricated by means of low temperature hot-pressing using hexagonal boron nitride (h-BN) and magnesium aluminum silicate (MAS) as raw materials. The influences of starting MAS content on the microstructural evolution and mechanical properties of the composites were investigated. The results indicate that the effective enhancement of relative density of composites has been achieved, which shows that MAS is an effective liquid-phase sintering aid during the hot-pressing. MAS also can improve the structural ordering of h-BN flakes. On the other hand, h-BN exhibits significant inhibiting effect on the crystallization of α-Cordierite. Furthermore, h-BN flakes with layered structure can play a role in strengthening the MAS matrix. So h-BN and MAS are considered to be co-enhanced by each other, resulting in better sintering ability and the mechanical properties of composite ceramics are better than that of both h-BN and MAS. Composite ceramics incorporated with 50 wt% MAS exhibits the highest bending strength and fracture toughness of 213±25 MPa and 2.49±0.35 MPa m{sup 1/2}, respectively.

  18. 超声声速测算在连续增韧陶瓷基复合材料检测中的可行性研究%Ultrasonic Velocity Measurement of Feasibility Study on Continuous Toughening Ceramic Matrix Composite Materials in the Detection

    Institute of Scientific and Technical Information of China (English)

    杜向阳; 段涵呓

    2015-01-01

    陶瓷基复合材料是一种重要的超高温材料,具有耐高温、低密度、高比强、高比模、抗氧化和抗烧蚀等优异性能,其中,性能最好的一种是连续纤维增韧陶瓷基复合材料。采用声速测算的方法对材料的质量进行评估,实现对材料不均匀性的质量评价。%Ceramic matrix composite is a kind of ultra high temperature material, has the advantages of high temperature resistance, low density, high specific strength, high specific modulus, antioxidant and anti ablation of excellent performance, the performance is the best, a continuous fiber reinforced composite material, Tao Ciji. Quality was evaluated by the sound velocity measuring method of material, the realization of the material is not uniform quality evaluation.

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

    Science.gov (United States)

    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

  20. Lower-Conductivity Ceramic Materials for Thermal-Barrier Coatings

    Science.gov (United States)

    Bansal, Narottam P.; Zhu, Dongming

    2006-01-01

    Doped pyrochlore oxides of a type described below are under consideration as alternative materials for high-temperature thermal-barrier coatings (TBCs). In comparison with partially-yttria-stabilized zirconia (YSZ), which is the state-of-the-art TBC material now in commercial use, these doped pyrochlore oxides exhibit lower thermal conductivities, which could be exploited to obtain the following advantages: For a given difference in temperature between an outer coating surface and the coating/substrate interface, the coating could be thinner. Reductions in coating thicknesses could translate to reductions in weight of hot-section components of turbine engines (e.g., combustor liners, blades, and vanes) to which TBCs are typically applied. For a given coating thickness, the difference in temperature between the outer coating surface and the coating/substrate interface could be greater. For turbine engines, this could translate to higher operating temperatures, with consequent increases in efficiency and reductions in polluting emissions. TBCs are needed because the temperatures in some turbine-engine hot sections exceed the maximum temperatures that the substrate materials (superalloys, Si-based ceramics, and others) can withstand. YSZ TBCs are applied to engine components as thin layers by plasma spraying or electron-beam physical vapor deposition. During operation at higher temperatures, YSZ layers undergo sintering, which increases their thermal conductivities and thereby renders them less effective as TBCs. Moreover, the sintered YSZ TBCs are less tolerant of stress and strain and, hence, are less durable.

  1. Matrix cracking of fiber-reinforced ceramic composites in shear

    Science.gov (United States)

    Rajan, Varun P.; Zok, Frank W.

    2014-12-01

    The mechanics of cracking in fiber-reinforced ceramic matrix composites (CMCs) under general loadings remains incomplete. The present paper addresses one outstanding aspect of this problem: the development of matrix cracks in unidirectional plies under shear loading. To this end, we develop a model based on potential energy differences upstream and downstream of a fully bridged steady-state matrix crack. Through a combination of analytical solutions and finite element simulations of the constituent stresses before and after cracking, we identify the dominant stress components that drive crack growth. We show that, when the axial slip lengths are much larger than the fiber diameter and when interfacial slip precedes cracking, the shear stresses in the constituents are largely unaffected by the presence of the crack; the changes that do occur are confined to a 'core' region within a distance of about one fiber diameter from the crack plane. Instead, the driving force for crack growth derives mainly from the axial stresses-tensile in the fibers and compressive in the matrix-that arise upon cracking. These stresses are well-approximated by solutions based on shear-lag analysis. Combining these solutions with the governing equation for crack growth yields an analytical estimate of the critical shear stress for matrix cracking. An analogous approach is used in deriving the critical stresses needed for matrix cracking under arbitrary in-plane loadings. The applicability of these results to cross-ply CMC laminates is briefly discussed.

  2. Materials Behavior Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The purpose is to evaluate mechanical properties of materials including metals, intermetallics, metal-matrix composites, and ceramic-matrix composites under typical...

  3. Polymer Coating for Immobilizing Soluble Ions in a Phosphate Ceramic Product

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dileep; Wagh, Arun S.; Patel, Kartikey D.

    1999-05-05

    A polymer coating is applied to the surface of a phosphate ceramic composite to effectively immobilize soluble salt anions encapsulated within the phosphate ceramic composite. The polymer coating is made from ceramic materials, including at least one inorganic metal compound, that wet and adhere to the surface structure of the phosphate ceramic composite, thereby isolating the soluble salt anions from the environment and ensuring long-term integrity of the phosphate ceramic composite.

  4. Mechanical properties of dispersed ceramic nanoparticles in polymer composites for orthopedic applications.

    Science.gov (United States)

    Liu, Huinan; Webster, Thomas J

    2010-04-15

    Ceramic/polymer composites have been considered as third-generation orthopedic biomaterials due to their ability to closely match properties (such as surface, chemistry, biological, and mechanical) of natural bone. It has already been shown that the addition of nanophase compared with conventional (or micron-scale) ceramics to polymers enhances bone cell functions. However, in order to fully take advantage of the promising nanometer size effects that nanoceramics can provide when added to polymers, it is critical to uniformly disperse them in a polymer matrix. This is critical since ceramic nanoparticles inherently have a strong tendency to form larger agglomerates in a polymer matrix which may compromise their properties. Therefore, in this study, model ceramic nanoparticles, specifically titania and hydroxyapatite (HA), were dispersed in a model polymer (PLGA, poly-lactic-co-glycolic acid) using high-power ultrasonic energy. The mechanical properties of the resulting PLGA composites with well-dispersed ceramic (either titania or HA) nanoparticles were investigated and compared with composites with agglomerated ceramic nanoparticles. Results demonstrated that well-dispersed ceramic nanoparticles (titania or HA) in PLGA improved mechanical properties compared with agglomerated ceramic nanoparticles even though the weight percentage of the ceramics was the same. Specifically, well-dispersed nanoceramics in PLGA enhanced the tensile modulus, tensile strength at yield, ultimate tensile strength, and compressive modulus compared with the more agglomerated nanoceramics in PLGA. In summary, supplemented by previous studies that demonstrated greater osteoblast (bone-forming cell) functions on well-dispersed nanophase ceramics in polymers, the present study demonstrated that the combination of PLGA with well-dispersed nanoceramics enhanced mechanical properties necessary for load-bearing orthopedic/dental applications.

  5. Method of Making an Electroactive Sensing/Actuating Material for Carbon Nanotube Polymer Composite

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2009-01-01

    An electroactive sensing or actuating material comprises a composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation of the composite when such composite is affected by an external stimulus. In another embodiment, the composite comprises a, third component of micro -sized to nano-sized particles of an electroactive ceramic that is also incorporated in the polymer matrix. The method for making the three-phase composite comprises either incorporating the carbon nanotubes in the polymer matrix before incorporation of the particles of ceramic or mixing the carbon nanotubes and particles of ceramic together in a solution before incorporation in the polymer matrix.

  6. Sensing/actuating materials made from carbon nanotube polymer composites and methods for making same

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2008-01-01

    An electroactive sensing or actuating material comprises a composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation of the composite when such composite is affected by an external stimulus. In another embodiment, the composite comprises a third component of micro-sized to nano-sized particles of an electroactive ceramic that is also incorporated in the polymer matrix. The method for making the three-phase composite comprises either incorporating the carbon nanotubes in the polymer matrix before incorporation of the particles of ceramic or mixing the carbon nanotubes and particles of ceramic together in a solution before incorporation in the polymer matrix.

  7. Process of producing a ceramic matrix composite article and article formed thereby

    Science.gov (United States)

    Corman, Gregory Scot; McGuigan, Henry Charles; Brun, Milivoj Konstantin

    2011-10-25

    A CMC article and process for producing the article to have a layer on its surface that protects a reinforcement material within the article from damage. The method entails providing a body containing a ceramic reinforcement material in a matrix material that contains a precursor of a ceramic matrix material. A fraction of the reinforcement material is present and possibly exposed at a surface of the body. The body surface is then provided with a surface layer formed of a slurry containing a particulate material but lacking the reinforcement material of the body. The body and surface layer are heated to form the article by converting the precursor within the body to form the ceramic matrix material in which the reinforcement material is contained, and by converting the surface layer to form the protective layer that covers any fraction of the reinforcement material exposed at the body surface.

  8. Fabrication and Performances of 1-3-2 Piezoelectric Ceramic/Polymer Composite

    Institute of Scientific and Technical Information of China (English)

    Likun Wang; Guang Li; Hongliang Du; Lei Qin; Shuxiang Li

    2006-01-01

    A novel 1-3-2 piezoelectric composite has been developed, which consists of piezoelectric ceramic plate and 1-3 piezoelectric composite. The composite was fabricated by dicing PZT ceramic along mutual perpendicular two directions and then filling epoxy into grooves. The piezoelectric and electromechanical properties of the novel composite were determined.The results show a coefficient d33 of 405 pC/N, a vibration displacement of 113.5 pm, an acoustic impendence of 13.3 Mraly,a bandwidth of 12 kHz and a thickness electromechanical coupling coefficient of 0.56.

  9. The Effect of Stochastically Varying Creep Parameters on Residual Stresses in Ceramic Matrix Composites

    Science.gov (United States)

    Pineda, Evan J.; Mital, Subodh K.; Bednarcyk, Brett A.; Arnold, Steven M.

    2015-01-01

    Constituent properties, along with volume fraction, have a first order effect on the microscale fields within a composite material and influence the macroscopic response. Therefore, there is a need to assess the significance of stochastic variation in the constituent properties of composites at the higher scales. The effect of variability in the parameters controlling the time-dependent behavior, in a unidirectional SCS-6 SiC fiber-reinforced RBSN matrix composite lamina, on the residual stresses induced during processing is investigated numerically. The generalized method of cells micromechanics theory is utilized to model the ceramic matrix composite lamina using a repeating unit cell. The primary creep phases of the constituents are approximated using a Norton-Bailey, steady state, power law creep model. The effect of residual stresses on the proportional limit stress and strain to failure of the composite is demonstrated. Monte Carlo simulations were conducted using a normal distribution for the power law parameters and the resulting residual stress distributions were predicted.

  10. Technical progress report during Phase 1 of the continuous fiber ceramic composites program

    Energy Technology Data Exchange (ETDEWEB)

    Richerson, D.W.

    1994-03-15

    United States industry has a critical need for materials that are lightweight, strong, tough, corrosion resistant and capable of performing at high temperatures; such materials will enable substantial increase in energy efficiency and reduction in emissions of pollutants. Continuous fiber ceramic composites (CFCCs) are an emerging class of materials which have the potential for the desired combination of properties to meet the industrial needs. A $10 billion annual market has been estimated for CFCC products by the year 2010, which equates to over 100,000 industrial sector jobs. The CFCC program began in the spring of 1992 as a three-phase 10-year effort to assess potential applications of CFCC materials, develop the necessary supporting technologies to design, analyze and test CFCC materials, conduct materials and process development guided by the applications assessment input, fabricate test samples and representative components to evaluate CFCC material capabilities under application conditions, and analyze scaleability and manufacturability plus demonstrate pilot-scale production engineering. DOE awarded 10 Phase I cooperative agreements to industry-lead teams plus identified generic supporting technology projects. This document highlights the broad progress and accomplishments on these contracts and support technology projects during Phase I.

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

    Science.gov (United States)

    1993-04-02

    h. Arrow shows AI,0 3 precipitate. 500x. Alumina-Silica Syvstem 33 Table 4 Hydrated Alumina and Aluminosilicates Name Chemical compound Diaspore ...Contracts and Grants It is my understanding that I will be notified in writing as to the action which the Institute intends to take in the disposition of...0.8(m P~ ~ re(m fl04 10 3a92-50 /mn 2e0h0.410 INTERFACES IN INTERMETALLIC AND CERAMIC MATRIX COMPOSITES peratures or to write fines on substrates".,r

  12. Comparative Study of Dielectric and Magnetic Properties of Selected 3D Reticulated Ceramics and Their Same Composition Ceramic Disks

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    3-dimensional reticulated ceramics (3DRCs) and their same composition ceramic disks(SCCDs) were fabricated by sol-gel method, with the composition of SrO.6Fe2O3(30%), SiC(35%) and TiO2(35%), sintered at 1200℃ in N2.The dielectric and magnetic parameters of such 3DRCs and their SCCDs were measured respectively in a temperature range from room temperature to 800℃ and in a frequency range from 2.6 GHz to 18 GHz. The results showed that the dielectric and magnetic loss of 3DRCs were obviously larger than those of their SCCDs in a wide range of temperature and the whole range of measuring frequency. The increase of dielectric loss of 3DRCs was much higher than that of magnetic loss compared to their SCCDs, which was found due to the 3D net structure extrinsic characteristics.

  13. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending June 30, 1984

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. (comp.)

    1984-11-01

    This report summarizes the activities of the Materials Sciences Program in the Metals and Ceramics Division for the period January 1, 1983, to June 30, 1984. These activities constitute about one-fourth of the research and development conducted by the division. The emphasis of the program can be described as the scientific design of materials. The efforts are directed toward three classes of materials: high-temperature metallic alloys based on intermetallic compounds, structural ceramics, and radiation-resistant alloys.

  14. High Speed Lapping of SiC Ceramic Material with Solid (Fixed) Abrasives

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; YANG Xin-hong; SHANG Chun-min; HU Xiao-yong; HU Zhong-hui

    2005-01-01

    An experimental investigation is carried out to machine SiC ceramic material through the method of high speed plane lapping with solid(fixed) abrasives after the critical condition of brittle-ductile transition is theoretically analyzed. The results show that the material removal mechanism and the surface roughness are chiefly related to the granularity of abrasives for brittle materials such as SiC ceramic. It is easily realized to machine SiC ceramic in the ductile mode using W3.5 grit and a high efficiency, low cost and smooth surface with a surface roughness of Ra 2.4nm can be achieved.

  15. Spark plasma sintering of silicon carbide, multi-walled carbon nanotube and graphene reinforced zirconium diboride ceramic composite

    Science.gov (United States)

    Balaraman Yadhukulakrishnan, Govindaraajan

    Scope and Method of Study: Space vehicles re-entering the earth's atmosphere experience very high temperatures due to aerodynamic heating. Ultra-high temperature ceramics (UHTC) with melting point higher than 3200°C are promising materials for thermal protection systems of such space vehicles re-entering the earth's atmosphere. Among several UHTC systems ZrB2 based ceramic composites are particularly important for thermal protection systems due to their better mechanical and thermoelectric properties and high oxidation resistance. In this study spark plasma sintering of SiC, carbon nanotubes (CNT) and graphene nano platelets (GNP) reinforced ZrB2 ultra-high temperature ceramic matrix composites is reported. Findings and Conclusions: Systematic investigations on the effect of reinforcement type (SiC, CNTs and GNP) and content (10-40 vol.% SiC, 2-6 vol.% CNTs and 2-6 vol.% GNP) on densification behavior, microstructure development, and mechanical properties (microhardness, bi-axial flexural strength, and indentation fracture toughness) are reported. With the similar SPS parameters near-full densification (>99% relative density) was achieved with 10-40 vol.% SiC, 4-6 vol.% CNT reinforced composites. Highly dense composites were obtained in 4-6 vol.% GNP reinforced composites. The SiC, CNT and GNP reinforcement improved the indentation fracture toughness of the composites through a range of toughening mechanisms, including particle shearing, crack deflection at the particle-matrix interface, and grain pull-outs for ZrB2-SiC composites, CNT pull-outs and crack deflection in ZrB2-CNT composites and crack deflection, crack bridging and GNP sheet pull-out for ZrB2 -GNP composites.

  16. A Review of Biomedical Composite Materials

    Institute of Scientific and Technical Information of China (English)

    吴珊珊

    2013-01-01

    This article addresses the review of the biomedical composite materials.It introduces the operational definition,the classification of biomedical composite materials,and its constituents within itself.In this thesis,the last part presents the application of this kind of material.By writing this paper,I hope that people will get a comprehensive knowledge of the biomedical composite material and make further and deeper research in this material by which way to animate the material science industry.

  17. The effect of different surface treatments on repair of CAD/CAM hybrid ceramic with resin composite

    Directory of Open Access Journals (Sweden)

    Özlem Acar

    2016-08-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the shear bond strength of novel hybrid ceramic material repaired with a composite resin. MATERIALS and METHOD: CAD/CAM hybrid ceramic (VITA Enamic specimens were prepared. The bonding surface was abraded with 600, 800 and 1200 grit SiC papers, and treated with air abrasion of 50 µm alumina particles. The specimens were assigned to four groups (n=12. G1: etching with 34% phosphoric acid + bonding with Adper Single Bond 2, G2: etching with 8% hydrofluoric acid + silane application + bonding with Adper Single Bond 2, G3: etching with 34% phosphoric acid + bonding with Single Bond Universal, G4: etching with 8% hydrofluoric acid + silane application + bonding with Single Bond Universal. Composite resin was build up on pretreated specimens and light-polymerized. The specimens were thermocycled 1000 times between 5±2 °C and 55±2 °C. Shear bond strength test was done by using a universal testing machine at a 1 mm/min crosshead speed. Data were statistically analyzed with One Way ANOVA and post-hoc Tukey HSD tests. Results: Comparison of the shear bond strength among groups revealed statistically significant differences (p<0.05. No statistically significant difference was found between G1 and G3 (p=0.591. Statistically significant differences were found between G1 and G2 (p=0.024, and G1 and G4 (p=0.013. Adhesive failure was observed in all groups. Conclusion: Hydrofluoric acid etching reduced the composite resin to hybrid ceramic shear bond strength. Etching with phosphoric acid followed by bonding with Adper Single Bond 2 or Single Bond Universal positively influenced the bond strength of composite resin to hybrid ceramic.

  18. Enhanced piezoelectric and mechanical properties of AlN-modified BaTiO3 composite ceramics.

    Science.gov (United States)

    Xu, Dan; Wang, Lidong; Li, Weili; Wang, Wei; Hou, Yafei; Cao, Wenping; Feng, Yu; Fei, Weidong

    2014-07-14

    BaTiO3-xAlN (BT-xAlN) composite ceramics were prepared by conventional solid state reaction sintering. The effects of the AlN content on the crystalline structures, densities, and electrical and mechanical properties of the BT ceramics were investigated. The BT-1.5%AlN ceramic exhibits a good piezoelectric constant of 305 pC N(-1) and an improved Vickers hardness of 5.9 GPa. The enhanced piezoelectricity originates from interactions between defect dipoles and spontaneous polarization inside the domains due to the occurrence of local symmetry, caused by the preferential distribution of the Al(3+)-N(3-) pairs vertical to the c axis. The hardening of the material is attributed to the improved density, and particle and grain boundary strengthening. Our work indicates that if a suitable doping ion pair is designed, lead-free ceramic systems prepared from ordinary raw materials by a conventional sintering method have a high probability of exhibiting good piezoelectric and mechanical properties simultaneously.

  19. Novel Hybrid Ablative/Ceramic Layered Composite for Earth Re-entry Thermal Protection: Microstructural and Mechanical Performance

    Science.gov (United States)

    Triantou, K.; Mergia, K.; Marinou, A.; Vekinis, G.; Barcena, J.; Florez, S.; Perez, B.; Pinaud, G.; Bouilly, J.-M.; Fischer, W. P. P.

    2015-04-01

    In view of spacecraft re-entry applications into planetary atmospheres, hybrid thermal protection systems based on layered composites of ablative materials and ceramic matrix composites are investigated. Joints of ASTERM™ lightweight ablative material with Cf/SiC (SICARBON™) were fabricated using commercial high temperature inorganic adhesives. Sound joints without defects are produced and very good bonding of the adhesive with both base materials is observed. Mechanical shear tests under ambient conditions and in liquid nitrogen show that mechanical failure always takes place inside the ablative material with no decohesion of the interface of the adhesive layer with the bonded materials. Surface treatment of the ablative surface prior to bonding enhances both the shear strength and the ultimate shear strain by up to about 60%.

  20. Determination of the raw material source used in the production of ceramics of the Hatahara archaeological site, AM, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Kelly P.; Munita, Casimiro S.; Oliveira, Paulo T.M.S., E-mail: kquimica@usp.b, E-mail: camunita@ipen.b, E-mail: poliver@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Neves, Eduardo G.; Kazuo, Eduardo T., E-mail: edgneves@usp.b, E-mail: eduardo.tamanaha@gmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Museu de Arqueologia e Etnologia; Soares, Emilio A.A., E-mail: easoares@usp.b [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Dept. de Geociencias

    2009-07-01

    The archaeological interventions carried out at the Hatahara archaeological site, located in the central Amazonia, showed the presence of a great amount of ceramic artifacts in this region. As a consequence, several works have been conducted with this archaeological material, searching clear questions on how the ancient societies produced such objects, as well as, the use they did of the environment where they were inserted. Considering that the analysis of the ceramic material showed the simultaneous occurrence of four distinct phases of occupation in the Hatahara site, which, in relation to its pre-colonial composition is as an integral part of a quite complex context, the present work had the purpose of helping the Archaeologists to understand better the development of the societies that occupied this region, with basis on the study of the archaeological ceramics provenance. For this, the chemical characterization was done, with application of the analytical technique by neutron activation analysis (NAA); the elementary concentrations of As, Ba, Ce, Co, Cr, Cs, Eu Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Ta, Tb, Th, U, Yb and Zn were determined in 127 ceramic fragments and in 7 samples of clay, collected next to the Hatahara archaeological site. The data of elementary concentrations were submitted to the multivariate statistical analysis, the techniques of cluster analysis and discriminant analysis. The results showed that a single type of clay was used in the manufacture of a group of 25 ceramic fragments, belonging to the phases Paredao, Manacapuru and Guarita. These results have been added to the archaeological interpretations with regard to the classification of the rescued ceramics fragments, in order to complement them. Therefore, this work supplied some pertinent clarifications that certainly will give support to the reconstruction of human path in the Hatahara archaeological site. (author)