WorldWideScience

Sample records for ceramic materials

  1. Ceramic Laser Materials

    OpenAIRE

    Guillermo Villalobos; Jasbinder Sanghera; Ishwar Aggarwal; Bryan Sadowski; Jesse Frantz; Colin Baker; Brandon Shaw; Woohong Kim

    2012-01-01

    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,...

  2. Reinforcement of ceramic materials

    International Nuclear Information System (INIS)

    In the commercial field, greater reproduceability of ceramic materials was achieved by systematic process control of the steps in manufacture. By improvement of the microstructure design, the strength and toughness against tearing of the materials were increased. The articles give a survey of theoretical and experimental results in manufacture and of the composition of ceramics with reinforced structure. Preferred materials are zirconium-, aluminium- and yttrium oxide, silicon oxide and -nitride and titanium- and silicon carbide. (DG)

  3. 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.

  4. 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.

  5. 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

  6. Method for Waterproofing Ceramic Materials

    Science.gov (United States)

    Cagliostro, Domenick E. (Inventor); Hsu, Ming-Ta S. (Inventor)

    1998-01-01

    Hygroscopic ceramic materials which are difficult to waterproof with a silane, substituted silane or silazane waterproofing agent, such as an alumina containing fibrous, flexible and porous, fibrous ceramic insulation used on a reentry space vehicle, are rendered easy to waterproof if the interior porous surface of the ceramic is first coated with a thin coating of silica. The silica coating is achieved by coating the interior surface of the ceramic with a silica precursor converting the precursor to silica either in-situ or by oxidative pyrolysis and then applying the waterproofing agent to the silica coated ceramic. The silica precursor comprises almost any suitable silicon containing material such as a silane, silicone, siloxane, silazane and the like applied by solution, vapor deposition and the like. If the waterproofing is removed by e.g., burning, the silica remains and the ceramic is easily rewaterproofed. An alumina containing TABI insulation which absorbs more that five times its weight of water, absorbs less than 10 wt. % water after being waterproofed according to the method of the invention.

  7. Improved ceramic heat exchange material

    Science.gov (United States)

    Mccollister, H. L.

    1977-01-01

    Improved corrosion resistant ceramic materials that are suitable for use as regenerative heat exchangers for vehicular gas turbines is reported. Two glass-ceramic materials, C-144 and C-145, have superior durability towards sulfuric acid and sodium sulfate compared to lithium aluminosilicate (LAS) Corning heat exchange material 9455. Material C-144 is a leached LAS material whose major crystalline phase is silica keatite plus mullite, and C-145 is a LAS keatite solid solution (S.S.) material. In comparison to material 9455, material C-144 is two orders of magnitude better in dimensional stability to sulfuric acid at 300 C, and one order of magnitude better in stability to sodium sulfate at 1000 C. Material C-145 is initially two times better in stability to sulfuric acid, and about one order of magnitude better in stability to sodium sulfate. Both C-144 and C-145 have less than 300 ppm delta L/L thermal expansion from ambient to 1000 C, and good dimensional stability of less than approximately 100 ppm delta L/L after exposure to 1000 C for 100 hours. The glass-ceramic fabrication process produced a hexagonal honeycomb matrix having an 85% open frontal area, 50 micrometer wall thickness, and less than 5% porosity.

  8. Natural Radioactivity in Ceramic Materials

    International Nuclear Information System (INIS)

    Ceramics are one of the most important types of the industrial building materials. The raw materials of the ceramic are made of a mixture of clay, feldspar, silica, talc kaolin minerals together with zirconium silicates (ZrSiO4).The ceramic raw materials and the final products contain naturally occurring radionuclide mainly U-238 and, Th-232 series, and the radioactive isotope of potassium K-40. Six raw ceramic samples were obtained from the Aracemco Company at Egypt together with a floor tile sample (final product) for measuring radioactive concentration levels., The activity of the naturally U-238, Th-232, and K-40 were determined as (Bq/kg) using gamma spectroscopy (Hyperactive pure germanium detector). Concentration of U and Th were determined in (ppm) using spectrophotometer technique by Arsenazo 111 and Piridy l-Azo -Resorcinol (PAR) indicators. Sequential extraction tests were carried out in order to determine the quantity of the radionuclide associated with various fractions as exchangeable, carbonate, acid soluble and in the residue. The results evaluated were compared to the associated activity indices (AI) that were defined by former USSR and West Germany

  9. 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.

  10. CVD COATING OF CERAMIC LAYERS ON CERAMIC CUTTING TOOL MATERIALS

    OpenAIRE

    Porat, R.

    1991-01-01

    When forming cutting tool materials based on ceramic components, one must take into considration the combination of wear resistance and mechanical properties which can withstand unfavorable cutting conditions at the same time maintaining high strength and fracture toughness. Ceramic cutting tools which are designed for machining at high cutting speeds and which have high strength and fracture toughness can be formed by applying a thin layer of ceramic materials on the substrate in order to in...

  11. High temperature fracture of ceramic materials

    International Nuclear Information System (INIS)

    A review is presented of fracture mechanisms and methods of lifetime prediction in ceramic materials. Techniques of lifetime prediction are based on the science of fracture mechanics. Application of these techniques to structural ceramics is limited by our incomplete understanding of fracture mechanisms in these materials, and by the occurrence of flaw generation in these materials at elevated temperatures. Research on flaw generation and fracture mechanisms is recommended as a way of improving the reliability of structural ceramics

  12. Measurement of Emissivity of Porous Ceramic Materials

    OpenAIRE

    BÜYÜKALACA, Orhan

    1998-01-01

    In this study, measurements of spectral and total emissivities of seven different porous ceramic materials and one ceramic fibre material are reported. Measurements were made for wavelength range from 1.2 µm to 20 µm and temperature range from 200 °C to 700 °C. It was found that total emissivity increases with increase of pore size but decreases with increase of temperature. The results showed all the porous ceramic materials tested to be much better than ceramic fibre in terms of total em...

  13. Ceramic Materials and Color in Dentistry

    OpenAIRE

    Volpato, Claudia; Fredel, Márcio; Philippi, Analúcia; PETTER, Carlos

    2010-01-01

    Since the introduction of metal ceramic crowns, clinicians and researchers have been looking for a restorative system that can associate beauty, strength and durability, but without the presence of a metallic infrastructure. Indeed, dental ceramics are materials that come aesthetically closest to natural teeth. With the improvement of ceramic systems, it has been possible to combine the excellent aesthetic characteristics of this material with a considerable resistance to fracture. It is impe...

  14. Insights on Ceramics as Dental Materials. Part I: Ceramic Material Types in Dentistry

    OpenAIRE

    Ho, GW; Matinlinna, JP

    2011-01-01

    Ceramics are widely used biomaterials in prosthetic dentistry due to their attractive clinical properties. They are aesthetically pleasing with their color, shade and luster, and they are chemically stable. The main constituents of dental ceramic are Si-based inorganic materials, such as feldspar, quartz, and silica. Traditional feldspar-based ceramics are also referred to as "Porcelain". The crucial difference between a regular ceramic and a dental ceramic is the proportion of feldspar, quar...

  15. Surface characterization of ceramic materials

    International Nuclear Information System (INIS)

    In recent years several techniques have become available to characterize the structure and chemical composition of surfaces of ceramic materials. These techniques utilize electron scattering and scattering of ions from surfaces. Low-energy electron diffraction is used to determine the surface structure, Auger electron spectroscopy and other techniques of electron spectroscopy (ultraviolet and photoelectron spectroscopies) are employed to determine the composition of the surface. In addition the oxidation state of surface atoms may be determined using these techniques. Ion scattering mass spectrometry and secondary ion mass spectrometry are also useful in characterizing surfaces and their reactions. These techniques, their applications and the results of recent studies are discussed. 12 figures, 52 references, 2 tables

  16. Oxygen diffusion in glasses and ceramic materials

    International Nuclear Information System (INIS)

    A survey is given on the published works to study oxygen diffusion in glasses and ceramic materials in the last years. In the first part methods are described for the measurement of oxygen diffusion coefficients and in the second part the published reports on oxygen diffusion in glasses, ceramic and other oxides are discussed. The most important results are summarized in different tables. (author)

  17. 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.

  18. Lightweight high performance ceramic material

    Science.gov (United States)

    Nunn, Stephen D [Knoxville, TN

    2008-09-02

    A sintered ceramic composition includes at least 50 wt. % boron carbide and at least 0.01 wt. % of at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy Ho, Er, Tm, Yb, and Lu, the sintered ceramic composition being characterized by a density of at least 90% of theoretical density.

  19. Study on Low Resistance PTC Ceramic Material

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The low resistance PTC ceramic thermistor material with excellent eleectrical properties are successfully fabricated by raw materials at industrial range made in our country on the study of its composition expression and fabrication process by using the addition of Nb, La, Y, Ta , microstructure regulator BN and ASTL phase .The composition and its fabrication method are studied.The relation of electrical properties of the PTC ceramic material to its composition expression and its related electrical properties are discussed.

  20. Dynamic properties of ceramic materials

    International Nuclear Information System (INIS)

    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

  1. 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.

  2. Photon CT scanning of advanced ceramic materials

    International Nuclear Information System (INIS)

    Advanced ceramic materials are being developed for high temperature applications in advanced heat engines and high temperature heat recovery systems. Small size flaws (10 - 200 μm) and small nonuniformities in density distributions (0.1 -2%) present as long-range density gradients, are critical in most ceramics and their detection is of crucial importance. Computed tomographic (CT) imaging provides a means of obtaining a precise two-dimensional density map of a cross section through an object from which accurate information about small flaws and small density gradients can be obtained. With the use of high energy photon sources high contrast CT images can be obtained for both low and high density ceramics. In the present paper we illustrate the applicability of the photon CT technique to the examination of advanced ceramics. CT images of sintered alumina tiles are presented from which data on high-density inclusions, cracks and density gradients have been extracted

  3. Novel polymer derived ceramic hard materials

    Energy Technology Data Exchange (ETDEWEB)

    Kaindl, A.; Lehner, W.; Greil, P. [Erlangen-Nuernberg Univ., Erlangen (Germany). Dept. of Mater. Sci.; Kim, D.J. [Sung Kyun Kwan Univ., Dept. of Materials Science, Suwon (Korea, Republic of)

    1997-12-31

    Manufacturing, microstructure and properties of novel ceramic hard materials derived from polymer/reactive filler mixtures were investigated. Carbide forming metal powders of Mo were used as fillers to react with the carbon bearing decomposition products of polymethylsiloxanes during pyrolysis in nitrogen atmosphere. Microcrystalline composites with the filler reaction product Mo{sub 2}C embedded in an amorphous SiOC-matrix could be formed with complex geometry due to near-netshape polymer/ceramic conversion. Depending on the filler and the pyrolysis conditions ceramic hard materials with Vickers hardness up to 10 GPa, fracture toughness of 5.1 MPa{radical}(m), a flexural strength of 330 MPa and a Youngs modulus of 280 GPa were obtained. (orig.) 8 refs.

  4. Smart Energy Materials of PZT Ceramics

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Okayasu

    2015-10-01

    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 [1,2].

  5. Glasses, ceramics, and composites from lunar materials

    Science.gov (United States)

    Beall, George H.

    1992-02-01

    A variety of useful silicate materials can be synthesized from lunar rocks and soils. The simplest to manufacture are glasses and glass-ceramics. Glass fibers can be drawn from a variety of basaltic glasses. Glass articles formed from titania-rich basalts are capable of fine-grained internal crystallization, with resulting strength and abrasion resistance allowing their wide application in construction. Specialty glass-ceramics and fiber-reinforced composites would rely on chemical separation of magnesium silicates and aluminosilicates as well as oxides titania and alumina. Polycrystalline enstatite with induced lamellar twinning has high fracture toughness, while cordierite glass-ceramics combine excellent thermal shock resistance with high flexural strengths. If sapphire or rutile whiskers can be made, composites of even better mechanical properties are envisioned.

  6. Glasses, ceramics, and composites from lunar materials

    Science.gov (United States)

    Beall, George H.

    1992-01-01

    A variety of useful silicate materials can be synthesized from lunar rocks and soils. The simplest to manufacture are glasses and glass-ceramics. Glass fibers can be drawn from a variety of basaltic glasses. Glass articles formed from titania-rich basalts are capable of fine-grained internal crystallization, with resulting strength and abrasion resistance allowing their wide application in construction. Specialty glass-ceramics and fiber-reinforced composites would rely on chemical separation of magnesium silicates and aluminosilicates as well as oxides titania and alumina. Polycrystalline enstatite with induced lamellar twinning has high fracture toughness, while cordierite glass-ceramics combine excellent thermal shock resistance with high flexural strengths. If sapphire or rutile whiskers can be made, composites of even better mechanical properties are envisioned.

  7. Fluorine 18 in tritium generator ceramic materials

    International Nuclear Information System (INIS)

    At present time, the ceramic materials generators of tritium are very interesting mainly by the necessity of to found an adequate product for its application as fusion reactor shielding. The important element that must contain the ceramic material is the lithium and especially the isotope with mass=6. The tritium in these materials is generated by neutron irradiation, however, when the ceramic material contains oxygen, then is generated too fluorine 18 by the action of energetic atoms of tritium in recoil on the 16 O, as it is showed in the next reactions: 1) 6 Li (n, α) 3 H ; 2) 16 O(3 H, n) 18 F . In the present work was studied the LiAlO2 and the Li2O. The first was prepared in the laboratory and the second was used such as it is commercially expended. In particular the interest of this work is to study the chemical behavior of fluorine-18, since if it would be mixed with tritium it could be contaminate the fusion reactor fuel. The ceramic materials were irradiated with neutrons and also the chemical form of fluorine-18 produced was studied. It was determined the amount of fluorine-18 liberated by the irradiated materials when they were submitted to extraction with helium currents and argon-hydrogen mixtures and also it was investigated the possibility about the fluorine-18 was volatilized then it was mixed so with the tritium. Finally it was founded that the liberated amount of fluorine-18 depends widely of the experimental conditions, such as the temperature and the hydrogen amount in the mixture of dragging gas. (Author)

  8. Fabrication of Bulk Nanocrystalline Ceramic Materials

    Czech Academy of Sciences Publication Activity Database

    Chráska, Tomáš; Neufuss, Karel; Dubský, Jiří; Ctibor, Pavel; Klementová, Mariana

    2008-01-01

    Roč. 17, 5-6 (2008), s. 872-877. ISSN 1059-9630 R&D Projects: GA AV ČR KAN300430651 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z40320502 Keywords : thermal spraying * nanocrystalline composites * wear Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.200, year: 2008

  9. Fusion ceramic materials and components

    International Nuclear Information System (INIS)

    Present-day approach for the radiation hardness assurance of components and materials for the International Thermonuclear Experimental Reactor ITER is based on extensive testing under representative conditions. Those conditions include radiation, temperature and vacuum and the possibility of in-situ monitoring of radiation-induced changes in characteristics of interest. The resistive bolometers are an example of an ITER component currently tested at SCK-CEN. Bolometers will be used for the plasma emission monitoring in high-radiation and high-temperature locations such as the divertor region. Previous tests with bolometers having gold strips on mica substrates were performed in the JMTR (Japan) and revealed problems of adhesion of the strips on the mica surface, which naturally has a very low roughness. A new type of the resistive bolometer based on platinum meander on alumina or aluminum-nitride (AlN) substrates have to be tested at a high neutron flux (0.01 dpa), high temperature (400 C) and in vacuum (10-3 mBar)- conditions appropriate for the ITER. Another illustration of on-going radiation testing for the ITER is the investigation of the Radiation-Induced Electrical Degradation (RIED). RIED is degradation of electrical insulation under the combined effect of radiation, temperature, vacuum and a strong electric field. It may be an issue to be dealt with in the design phase. Our objective is to develop instrumentation capabilities, which can provide in-situ data on the radiation hardness of materials and components intended for the use in the ITER. These capabilities will allow assessment of the performance parameters under conditions representative in terms of radiation load, temperature and vacuum, and will include on-line electric measurements

  10. Addition of alternative materials to ceramic slabs

    Directory of Open Access Journals (Sweden)

    E. O. B. Nara

    2014-09-01

    Full Text Available The construction market is very growing, leading to the emergence of new technologies and materials, and a growing need for sustainable products for the construction process, and the call for quality of life we present the description of a new option alternative materials for environments that require careful with the acoustics. The research covers the development and incorporation of new material in construction, with the potential acoustic, from tests and measurements with calibrated decibel meter called. We also used the ceramic tiles pre-molded, used for making floors or ceilings in buildings and homes. The methodology used for the development of this research was characterized as literature, exploratory, descriptive, qualitative and quantitative, alternative and affordable. How after the analysis results of the tests performed it can be seen that the incorporation of rice hulls of agglomerated to form ceramic tiles, possible reductions in noise levels on the order of 8 dB (A than the traditional construction of the buildings, and then an excellent material. This research contributes to the construction so that presented a description of a new product developed from a conventional material, originating in agriculture, waste rice husk and its incorporation during the construction of buildings and home, with the potential acoustic observed from tests and measurements with calibrated decibel meter called.

  11. Ceramic nanostructure materials, membranes and composite layers

    OpenAIRE

    Burggraaf, A.J.; Keizer, K.; Hassel, van, E Edwin

    1989-01-01

    Synthesis methods to obtain nanoscale materials will be briefly discussed with a focus on sol-gel methods. Three types of nanoscale composites (powders, membranes and ion implanted layers) will be discussed and exemplified with recent original research results. Ceramic membranes with a thickness of 1–10 μm consist of a packing of elementary particles with a size of 3–7 nm. The mean pore size is about 2.5–3 nm. The preparation routes are based on sol and sol-gel technologies. The pores can be ...

  12. Rare earths in ceramic materials technology

    International Nuclear Information System (INIS)

    Rare earth elements are mainly exploited for electronic devices, but far from negligible is their importance in materials for structural applications, i.e. for their mechanical properties, useful in modern technologies. For example, widely renown is the role of rare earth oxides in the study of zirconia (zirconium dioxide, ZrO2), by far the most interesting ceramic material for structural applications. Among rare earth oxides, ceria (cerium dioxide, CeO2) has played a fundamental role because at room temperature it stabilizes the tetragonal phase of zirconia, which is the most interesting phase from a mechanical point of view. In this presentation the main characteristics of the system CeO2-ZrO2 are outlined, along with the mechanical properties of binary alloys of the two oxides; these properties are evaluated as a function of their composition and microstructure. Some of these alloys exhibited behaviour completely unexpected for ceramic materials, e.g. the Shape Memory Effect (SME) and the Gorsky Effect. (orig.)

  13. Laser hearth melt processing of ceramic materials

    Science.gov (United States)

    Richard Weber, J. K.; Felten, J. J.; Nordine, Paul C.

    1996-02-01

    A new technique for synthesizing small batches of oxide-based ceramic and glass materials from high purity powders is described. The method uses continuous wave CO2 laser beam heating of material held on a water-cooled copper hearth. Contamination which would normally result during crucible melting is eliminated. Details of the technique are presented, and its operation and use are illustrated by results obtained in melting experiments with a-aluminum oxide, Y-Ba-Cu-O superconductor material, and the mixtures, Al2O3-SiO2, Bi2O3-B2O3, Bi2O3-CuO. Specimen masses were 0.05-1.5 g.

  14. 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

  15. Tough hybrid ceramic-based material with high strength

    International Nuclear Information System (INIS)

    This study describes a tough and strong hybrid ceramic material consisting of platelet-like zirconium compounds and metal. A mixture of boron carbide and excess zirconium powder was heated to 1900 °C using a liquid-phase reaction sintering technique to produce a platelet-like ZrB2-based hybrid ceramic bonded by a thin zirconium layer. The platelet-like ZrB2 grains were randomly present in the as-sintered hybrid ceramic. Relative to non-hybrid ceramics, the fracture toughness and flexural strength of the hybrid ceramic increased by approximately 2-fold.

  16. UV laser micromachining of ceramic materials: formation of columnar topographies

    International Nuclear Information System (INIS)

    Laser machining is increasingly appearing as an alternative for micromachining of ceramics. Using ceramic materials using excimer lasers can result in smooth surfaces or in the formation of cone-like or columnar topography. Potential applications of cone-shaped or columnar surface topography include, for example, light trapping in anti-reflection coatings and improvement of adhesion bonding between ceramic materials. In this communication results of a comparative study of surface topography change during micromachining of several ceramic materials with different ablation behaviors are reported. (orig.)

  17. Emerging Ceramic-based Materials for Dentistry

    OpenAIRE

    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 appr...

  18. 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

  19. Elastic properties of various ceramic materials

    International Nuclear Information System (INIS)

    The Young's modulus and the Poisson's ratio of various ceramics have been investigated at room temperature and compared with data from the literature. The ceramic materials investigated are Al2O3, Al2O3-ZrO2, MgAl2O4, LiAlO2, Li2SiO3, Li4SiO4, UO2, AlN, SiC, B4C, TiC, and TiB2. The dependence of the elastic moduli on porosity and temperature have been reviewed. Measurements were also performed on samples of Al2O3, AlN, and SiC, which had been irradiated to maximum neutron fluences of 1.6.1026 n/m2 (E>0.1 MeV) at different temperatures. The Young's modulus is nearly unaffected at fluences up to about 4.1024 n/m2. However, it decreases with increasing neutron fluence and seems to reach a saturation value depending upon the irradiation temperature. The reduction of the Young's modulus is lowest in SiC. (orig.)

  20. Calculation of the bio-ceramic material parameters

    Czech Academy of Sciences Publication Activity Database

    Fuis, Vladimír; Janíček, Přemysl

    Berlin : Springer, 2014, s. 855-861. ISBN 978-3-319-02293-2. [Mechatronics 2013 /10./. Brno (CZ), 07.10.2013-09.10.2013] R&D Projects: GA ČR GA13-34632S Institutional support: RVO:61388998 Keywords : ceramics * material parameters * weibull Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  1. Ceramic materials for fission and fusion nuclear reactors

    International Nuclear Information System (INIS)

    A general survey on the ceramics for nuclear applications is presented. For the fission nuclear reactor, the ceramics materials are almost totally used as fuel e.g. (U,Pu)O2; other types of ceramics, e.g. Uranium-Plutonium carbide and nitride, have been investigated as potential nuclear fuels. The (U,Pu)N compound is to be the fuel for the space nuclear power reactor in the U.S.A. For the fusion nuclear reactor, the ceramics should be the fundamental materials for many components: first wall, breeder, RF heating systems, insulant and shielding parts, etc. In recent years many countries are involved on the research and development of ceramic compounds with the principal purpose of being used in the fusion powerplant (year 2010-2020 ?). An effort has been even made to verify if it is possible to use more ceramic components in the fission nuclear plant (probably differntly disigned) to improve the safety level

  2. A new ceramic material for shielding pulsed neutron scattering instruments

    International Nuclear Information System (INIS)

    We propose a new ceramic composite, based on boron carbide, to use as a shielding material for pulsed neutron scattering instrumentation. The measured transmission data show characteristics equivalent to crispy mix, a common shielding material used at ISIS (UK)

  3. Ceramic fiber-reinforced monoclinic celsian phase glass-ceramic matrix composite material

    Science.gov (United States)

    Bansal, Narottam P. (Inventor); Dicarlo, James A. (Inventor)

    1994-01-01

    A hyridopolysilazane-derived ceramic fiber reinforced monoclinic celsian phase barium aluminum silicate glass-ceramic matrix composite material is prepared by ball-milling an aqueous slurry of BAS glass powder and fine monoclinic celsian seeds. The fibers improve the mechanical strength and fracture toughness and with the matrix provide superior dielectric properties.

  4. Development of Ceramic Solid-State Laser Host Material

    Science.gov (United States)

    Prasad, Narasimha S.; Trivedi, Sudhir; Kutcher, Susan; Wang, Chen-Chia; Kim, Joo-Soo; Hommerich, Uwe; Shukla, Vijay; Sadangi, Rajendra

    2009-01-01

    Polycrystalline ceramic laser materials are gaining importance in the development of novel diode-pumped solid-state lasers. Compared to single-crystals, ceramic laser materials offer advantages in terms of ease of fabrication, shape, size, and control of dopant concentrations. Recently, we have developed Neodymium doped Yttria (Nd:Y2O3) as a solid-state ceramic laser material. A scalable production method was utilized to make spherical non agglomerated and monodisperse metastable ceramic powders of compositions that were used to fabricate polycrystalline ceramic material components. This processing technique allowed for higher doping concentrations without the segregation problems that are normally encountered in single crystalline growth. We have successfully fabricated undoped and Neodymium doped Yttria material up to 2" in diameter, Ytterbium doped Yttria, and erbium doped Yttria. We are also in the process of developing other sesquioxides such as scandium Oxide (Sc2O3) and Lutesium Oxide (Lu2O3) doped with Ytterbium, erbium and thulium dopants. In this paper, we present our initial results on the material, optical, and spectroscopic properties of the doped and undoped sesquioxide materials. Polycrystalline ceramic lasers have enormous potential applications including remote sensing, chem.-bio detection, and space exploration research. It is also potentially much less expensive to produce ceramic laser materials compared to their single crystalline counterparts because of the shorter fabrication time and the potential for mass production in large sizes.

  5. Hot corrosion of ceramic engine materials

    Science.gov (United States)

    Fox, Dennis S.; Jacobson, Nathan S.; Smialek, James L.

    1988-01-01

    A number of commercially available SiC and Si3N4 materials were exposed to 1000 C in a high velocity, pressurized burner rig as a simulation of a turbine engine environment. Sodium impurities added to the burner flame resulted in molten Na2SO4 deposition, attack of the SiC and Si4N4 and formation of substantial Na2O-x(SiO2) corrosion product. Room temperature strength of the materials decreased. This was a result of the formation of corrosion pits in SiC, and grain boundary dissolution and pitting in Si3N4. Corrosion regimes for such Si-based ceramics have been predicted using thermodynamics and verified in rig tests of SiO2 coupons. Protective mullite coatings are being investigated as a solution to the corrosion problem for SiC and Si3N4. Limited corrosion occurred to cordierite (Mg2Al4Si5O18) but some cracking of the substrate occurred.

  6. 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.

  7. Proceedings of the national symposium on materials and processing: functional glass/glass-ceramics, advanced ceramics and high temperature materials

    International Nuclear Information System (INIS)

    With the development of materials science it is becoming increasingly important to process some novel materials in the area of glass, advanced ceramics and high temperature metals/alloys, which play an important role in the realization of many new technologies. Such applications demand materials with tailored specifications. Glasses and glass-ceramics find exotic applications in areas like radioactive waste storage, optical communication, zero thermal expansion coefficient telescopic mirrors, human safety gadgets (radiation resistance windows, bullet proof apparels, heat resistance components etc), biomedical (implants, hyperthermia treatment, bone cement, bone grafting etc). Advanced ceramic materials have been beneficial in biomedical applications due to their strength, biocompatibility and wear resistance. Non-oxide ceramics such as carbides, borides, silicides, their composites, refractory metals and alloys are useful as structural and control rod components in high temperature fission/ fusion reactors. Over the years a number of novel processing techniques like selective laser melting, microwave heating, nano-ceramic processing etc have emerged. A detailed understanding of the various aspects of synthesis, processing and characterization of these materials provides the base for development of novel technologies for different applications. Keeping this in mind and realizing the need for taking stock of such developments a National Symposium on Materials and Processing -2012 (MAP-2012) was planned. The topics covered in the symposium are ceramics, glass/glass-ceramics and metals and materials. Papers relevant to INIS are indexed separately

  8. Exotic development of ceramic tritium breeding materials

    International Nuclear Information System (INIS)

    In the near future fusion reactors will be based on the tritium-deuterium plasma reaction. As such the production of tritium, a non-natural element, becomes of crucial importance in fusion technology. An experimental programme, EXOTIC, is in progress since 1983 in which the laboratories of SNL-Springfields, ECN-Petten, JRC-Petten and SCK-CEN Mol work in close collaboration within the framework of the manufacture, characterization and irradiation of ceramic lithium compounds. This programme must result in the understanding of the tritium release processes and the effect of material characteristics on this release. Up to now three irradiation experiments in the High Flux Reactor-Petten were scheduled (EXOTIC I, II and III). The Annual Progress Report 1985 summarizes information on these experiments during the period of 1985. The reader is also referred to the previous Annual Progress Report 1984. During the EXOTIC I experiment lithium silicate pellets and lithium aluminate pellets were irradiated. The resulting tritium release data are still to be interpreted in full detail. Some preliminary observations are presented in this Report. In the EXOTIC II experiment lithium oxide, lithium aluminate and lithium silicate pellets were used. In the EXOTIC III experiment lithium oxide, lithium zirconate and lithium silicate pellets were used. (Author)

  9. 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,...

  10. Sealing ceramic material in low melting point glass

    Science.gov (United States)

    Moritoki, M.; Fujikawa, T.; Miyanaga, J.

    1984-01-01

    A structured device placed in an aerated crucible to pack ceramics molding substance that is to be processed was designed. The structure is wrapped by sealing material made of pyrex glass and graphite foil or sheet with a weight attached on top of it. The crucible is made of carbon; the ceramics material to be treated through heat intervenient press process is molding substance consisting mainly of silicon nitride.

  11. Aluminium nitrate ceramics: A potential UV dosemeter material

    DEFF Research Database (Denmark)

    Trinkler, L.; Bøtter-Jensen, L.; Berzina, B.

    The ceramic material AIN-Y2O3 is proposed as a potential ultraviolet radiation (UVR) dosemeter using optically stimulated luminescence (OSL) and thermally stimulated luminescence (TL). Experimental studies have shown that AIN ceramics exhibit attractive characteristics suitable for practical UV...... Al2O3:C; and (4) a large dynamic range TL signal (5 orders of magnitude). Although there is relatively high fading, it is demonstrated that AIN is a feasible material for UVR dosimetry using short integration times....

  12. 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.

  13. Wear characteristics of polished and glazed lithium disilicate ceramics opposed to three ceramic materials.

    Science.gov (United States)

    Saiki, Osamu; Koizumi, Hiroyasu; Akazawa, Nobutaka; Kodaira, Akihisa; Okamura, Kentaro; Matsumura, Hideo

    2016-01-01

    This study compared the wear characteristics of a heat-pressed lithium disilicate ceramic material opposed to feldspathic porcelain, a lithium disilicate glass ceramic, and zirconia materials. Ceramic plate specimens were prepared from feldspathic porcelain (EX-3 nA1B), lithium disilicate glass ceramics (e.max CAD MO1/C14), and zirconia (Katana KT 10) and then ground or polished. Rounded rod specimens were fabricated from heat-pressed lithium disilicate glass ceramic (e.max press LT A3) and then glazed or polished. A sliding wear testing apparatus was used for wear testing. Wear of glazed rods was greater than that of polished rods when they were abraded with ground zirconia, ground porcelain, polished porcelain, or polished lithium disilicate ceramics. For both glazed and polished rods, wear was greater when the rods were abraded with ground plates. The findings indicate that application of a polished surface rather than a glazed surface is recommended for single restorations made of heat-pressed lithium disilicate material. In addition, care must be taken when polishing opposing materials, especially those used in occlusal contact areas. (J Oral Sci 58, 117-123, 2016). PMID:27021548

  14. Research and development status of ceramic breeder materials

    International Nuclear Information System (INIS)

    The breeding blanket is a key component of the fusion reactor because it directly involves tritium breeding and energy extraction, both of which are critical to development of fusion power. The lithium ceramics continue to show promise as candidate breeder materials. This promise was also recognized by the International Thermonuclear Experimental Reactor (ITER) design team in its selection of ceramics as the first option breeder material. Blanket design studies have indicated areas in the properties data base that need further investigation. Current studies are focusing on issues such as tritium release behavior at high burnup, changes in thermophysical properties with burnup, compatibility between ceramic breeder and beryllium multiplier, and phase changes with burnup. Laboratory and in-reactor tests are underway, some as part of an international collaboration for development of ceramic breeder materials. 36 refs

  15. Reactivity of ceramic coating materials with uranium and uranium trichlorid

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Ho; Cho, Choon Ho; Lee, Yoon Sang; Lee, Han Soo; Kim, Jeong Guk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-05-15

    Uranium and uranium alloys are typically induction melted in graphite crucibles under a vacuum. The graphite crucible is used for the manufacturing of uranium ingots in the casting equipment. But, due to the chemical reactivity of uranium and most alloying elements with carbon, a protective ceramic coating is generally applied to the crucibles. In this study, to investigate the most suitable ceramic coating material applied to graphite melting crucibles and ingot moldsused in the melting and casting of uranium in the casting equipment, firstly, the thermodynamic analysis was performed by using HSC software to investigate the reactivity between uranium and several ceramic materials and the experiments on the reaction of ceramic coated crucibles in molten uranium were carried out at 1300 .deg. C

  16. Reactivity of ceramic coating materials with uranium and uranium trichlorid

    International Nuclear Information System (INIS)

    Uranium and uranium alloys are typically induction melted in graphite crucibles under a vacuum. The graphite crucible is used for the manufacturing of uranium ingots in the casting equipment. But, due to the chemical reactivity of uranium and most alloying elements with carbon, a protective ceramic coating is generally applied to the crucibles. In this study, to investigate the most suitable ceramic coating material applied to graphite melting crucibles and ingot moldsused in the melting and casting of uranium in the casting equipment, firstly, the thermodynamic analysis was performed by using HSC software to investigate the reactivity between uranium and several ceramic materials and the experiments on the reaction of ceramic coated crucibles in molten uranium were carried out at 1300 .deg. C

  17. Improvements in the processing of Yb:YAG ceramic materials

    OpenAIRE

    Serantoni, Marina; Esposito, Laura; Piancastelli, Andreana; Alderighi, Daniele; Pirri, Angela

    2010-01-01

    Laser ceramics can attain a significant role in the frame of the generation of high peak power, high energy laser pulses at high repetition rate, applications where fiber lasers or single crystals undergo fundamental or technological limitations. A ceramic material in order to be used as a laser amplifier, needs to fulfil strict requirements in terms of properties, in particular microstructure, purity level, porosity. The important role played by the production process on the transparency of ...

  18. Optical ceramics for fast scintillator materials

    Czech Academy of Sciences Publication Activity Database

    Nikl, Martin; Yanagida, T.; Yagi, H.; Yanagitani, T.; Mihóková, Eva; Yoshikawa, A.

    New York: Nova Science Publishers, 2013 - (Roa Rovira, J.; Rubi, M.), s. 127-176 ISBN 9781624177293 R&D Projects: GA MŠk LH12150; GA AV ČR KAN300100802 Institutional support: RVO:68378271 Keywords : scintillators * ceramics * oxides * halides * nanocomposites Subject RIV: BM - Solid Matter Physics ; Magnetism

  19. Valorization of rice straw waste: an alternative ceramic raw material

    Directory of Open Access Journals (Sweden)

    Á. Guzmán A

    2015-03-01

    Full Text Available In the production of rice a large amount of solid residue is produced, for which alternative utilizations are scarce or are not commonly applied in industry. Rice straw (RS is a waste product of rice harvest that is generated in equal or greater quantities than the rice itself. RS is frequently burned in open air, which makes it a significant source of pollution. In the search for possible uses of RS, it should be noted that its ash (RSA is particularly rich in silica, alkaline and alkaline earth metals and may be used as a source of alkalis and silica for the production of triaxial ceramics. The present research work proposes the production of a ceramic raw material from RS for its use in the fabrication of ceramic materials for the construction industry. Based on the chemical and mineralogical composition of RSA created under different thermal conditions, the most suitable RSA for this purpose was that obtained from treating RS at a temperature of 800 ºC for a time of 2 h. The resulting RSA presented high contents of SiO2 (79.62%, alkaline oxides (K2O (10.53% and alkaline earth oxides (CaO (2.80%. It is concluded that RSA is a new alternative ceramic raw material that can be used as a replacement for the fluxing (mainly feldspar and inert (quartz materials that are used in the production of triaxial ceramics.

  20. 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.

  1. 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.

  2. Ceramic matrix composites -- Advanced high-temperature structural materials

    International Nuclear Information System (INIS)

    This symposium on Ceramic Matrix Composites: Advanced High-Temperature Structural Materials was held at the 1994 MRS Fall Meeting in Boston, Massachusetts on November 28--December 2. The symposium was sponsored by the Department of Energy's Office of Industrial Technology's Continuous Fiber Ceramic Composites Program, the Air Force Office of Scientific Research, and NASA Lewis Research Center. Among the competing materials for advanced, high-temperature applications, ceramic matrix composites are leading candidates. The symposium was organized such that papers concerning constituents--fibers and matrices--were presented first, followed by composite processing, modeling of mechanical behavior, and thermomechanical testing. More stable reinforcements are necessary to enhance the performance and life of fiber-reinforced ceramic composites, and to ensure final acceptance of these materials for high-temperature applications. Encouraging results in the areas of polymer-derived SiC fibers and single crystal oxide filaments were given, suggesting composites with improved thermomechanical properties and stability will be realized in the near future. The significance of the fiber-matrix interface in the design and performance of these materials is evident. Numerous mechanical models to relate interface properties to composite behavior, and interpret test methods and data, were enthusiastically discussed. One issue of great concern for any advanced material for use in extreme environments is stability. This theme arose frequently throughout the symposium and was the topic of focus on the final day. Fifty nine papers have been processed separately for inclusion on the data base

  3. The possibility of giant dielectric materials for multilayer ceramic capacitors

    OpenAIRE

    Ishii, Tatsuya; Endo, Makoto; Masuda, Kenichiro; Ishida, Keisuke

    2013-01-01

    There have been numerous reports on discovery of giant dielectric permittivity materials called internal barrier layer capacitor in the recent years. We took particular note of one of such materials, i.e., BaTiO3 with SiO2 coating. It shows expressions of giant electric permittivity when processed by spark plasma sintering. So we evaluated various electrical characteristics of this material to find out whether it is applicable to multilayer ceramic capacitors. Our evaluation revealed that the...

  4. Overview: Damage resistance of graded ceramic restorative materials

    OpenAIRE

    Zhang, Yu

    2012-01-01

    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 examin...

  5. Ceramic material which absorbs neutrons and its uses

    International Nuclear Information System (INIS)

    A ceramic material, which absorbs thermal and epithermal neutrons even at high temperatures, consists of a basic material absorbing neutrons and 5 to 50% by weight relative to the total weight of the material of at least one of the hydrides of zirconium, yttrium and/or at least one of the rare earth elements, and possibly a binder, and the usual fillers and auxiliaries. (orig.)

  6. The Uniaxial Tensile Response of Porous and Microcracked Ceramic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Amit [ORNL; Shyam, Amit [ORNL; Watkins, Thomas R [ORNL; Lara-Curzio, Edgar [ORNL; Lara-Curzio, Edgar [ORNL; Stafford, Randall [Cummins, Inc; Hemker, Kevin J [Johns Hopkins University

    2014-01-01

    The uniaxial tensile stress-strain behavior of three porous ceramic materials was determined at ambient conditions. Test specimens in the form of thin beams were obtained from the walls of diesel particulate filter honeycombs and tested using a microtesting system. A digital image correlation technique was used to obtain full-field 2D in-plane surface displacement maps during tensile loading, and in turn, the 2D strains obtained from displacement fields were used to determine the Secant modulus, Young s modulus and initial Poisson s ratio of the three porous ceramic materials. Successive unloading-reloading experiments were performed at different levels of stress to decouple the linear elastic, anelastic and inelastic response in these materials. It was found that the stress-strain response of these materials was non-linear and that the degree of nonlinearity is related to the initial microcrack density and evolution of damage in the material.

  7. Ceramic waste materials – source for the geopolymer technology

    Czech Academy of Sciences Publication Activity Database

    Perná, Ivana; Hanzlíček, Tomáš; Straka, Pavel; Steinerová, Michaela

    Hammamed: SDST, 2008 - (Darve, F.), s. 735-740 ISBN 978-9973-0-0299-0. [Second Euro Mediterranean Symposium in Advances on Geomaterials and Structures. Hammamet (TN), 05.05.2008-08.05.2008] Institutional research plan: CEZ:AV0Z30460519 Keywords : ceramic waste material * white waters * geopolymer Subject RIV: DM - Solid Waste and Recycling

  8. 3rd Workshop on metal ceramic materials for functional applications

    International Nuclear Information System (INIS)

    This workshop contains contributions about materials and processing, characterization and modeling of properties and applications of metallic ceramics and composite structures. It was held on behalf of the Taiwan-Austrian scientific collaboration in Vienna, June 4th - 6th 1997. (Suda)

  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. Neutron irradiation of candidate ceramic breeder materials of fusion reactors

    International Nuclear Information System (INIS)

    In the context of the European programs for the future fusion reactors, the Process Chemistry Department of ENEA, Casaccia Center (Rome), has been involved in preparing ceramic blanket materials as tritium breeders; a special consideration has been addressed to the nuclear characterization of LiAlO2 and Li2ZrO3. In this paper are reported neutron irradiation of ceramic specimens in TRIGA reactor and γ-spectrometric measurements for INAA purposes; and isothermal annealing of the irradiated samples and tritium extraction, by using an 'out of pile' system. (author) 3 refs.; 4 figs.; 4 tabs

  11. Phosphate bonded ceramics as candidate final-waste-form materials

    International Nuclear Information System (INIS)

    Room-temperature setting phosphate-bonded ceramics were studied as candidate materials for stabilization of DOE low-level problem mixed wastes which cannot be treated by other established stabilization techniques. Phosphates of Mg, Mg-Na, Al and Zr were studied to stabilize ash surrogate waste containing RCRA metals as nitrates and RCRA organics. We show that for a typical loading of 35 wt.% of the ash waste, the phosphate ceramics pass the TCLP test. The waste forms have high compression strength exceeding ASTM recommendations for final waste forms. Detailed X-ray diffraction studies and differential thermal analyses of the waste forms show evidence of chemical reaction of the waste with phosphoric acid and the host matrix. The SEM studies show evidence of physical bonding. The excellent performance in the leaching tests is attributed to a chemical solidification and physical as well as chemical bonding of ash wastes in these phosphate ceramics

  12. Glass-ceramics: A class of nanostructured materials for photonics

    International Nuclear Information System (INIS)

    Glass-ceramics (GCs) are constituted by nanometer–to–micron-sized crystals embedded in a glass matrix; usually, their structural or functional elements (clusters, crystallites or molecules) have dimensions in the 1 to 100 nm range. As the name says, GCs must be considered an intermediate material between inorganic glasses and ceramics; in most cases the crystallinity is between 30 and 50%. GCs share many properties with both glasses and ceramics, offering low defects, extra hardness, high thermal shock resistance (typical of ceramics) together with the ease of fabrication and moulding (typical of glasses). The embedded crystalline phase, however, can enhance the existing properties of the matrix glass or lead to entirely new properties. GCs are produced by controlled crystallization of certain glasses, generally induced by nucleating additives; they may result opaque or transparent. Transparent GCs are now gaining a competitive advantage with respect to amorphous glasses and, sometimes, to crystals too. The aim of the present paper is to introduce the basic characteristics of transparent glass-ceramics, with particular attention to the relationship between structure and transparency and to the mechanism of crystallization, which may also be induced by selective laser treatments. Their applications to the development of guided-wave structures are also briefly described.

  13. Glass-ceramics: A class of nanostructured materials for photonics

    Science.gov (United States)

    de Pablos-Martin, A.; Ferrari, M.; Pascual, M. J.; Righini, G. C.

    2015-07-01

    Glass-ceramics (GCs) are constituted by nanometer-to-micron-sized crystals embedded in a glass matrix; usually, their structural or functional elements (clusters, crystallites or molecules) have dimensions in the 1 to 100nm range. As the name says, GCs must be considered an intermediate material between inorganic glasses and ceramics; in most cases the crystallinity is between 30 and 50%. GCs share many properties with both glasses and ceramics, offering low defects, extra hardness, high thermal shock resistance (typical of ceramics) together with the ease of fabrication and moulding (typical of glasses). The embedded crystalline phase, however, can enhance the existing properties of the matrix glass or lead to entirely new properties. GCs are produced by controlled crystallization of certain glasses, generally induced by nucleating additives; they may result opaque or transparent. Transparent GCs are now gaining a competitive advantage with respect to amorphous glasses and, sometimes, to crystals too. The aim of the present paper is to introduce the basic characteristics of transparent glass-ceramics, with particular attention to the relationship between structure and transparency and to the mechanism of crystallization, which may also be induced by selective laser treatments. Their applications to the development of guided-wave structures are also briefly described.

  14. Nondestructive evaluation of a ceramic matrix composite material

    Science.gov (United States)

    Grosskopf, Paul P.; Duke, John C., Jr.

    1992-01-01

    Monolithic ceramic materials have proven their usefulness in many applications, yet, their potential for critical structural applications is limited because of their sensitivity to small imperfections. To overcome this extreme sensitivity to small imperfections, ceramic matrix composite materials have been developed that have the ability to withstand some distributed damage. A borosilicate glass reinforced with several layers of silicon-carbide fiber mat has been studied. Four-point flexure and tension tests were performed not only to determine some of the material properties, but also to initiate a controlled amount of damage within each specimen. Acousto-ultrasonic (AU) measurements were performed periodically during mechanical testing. This paper will compare the AU results to the mechanical test results and data from other nondestructive methods including acoustic emission monitoring and X-ray radiography. It was found that the AU measurements were sensitive to the damage that had developed within the material.

  15. 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. PMID:21733619

  16. INTELLIGENT MATERIALS BASED ON CERAMIC COMPOSITES

    OpenAIRE

    Maximov, Y.; Merzlikin, V.; Sidorov, O.; Suttugin, V.

    2010-01-01

    The paper examines the possibility to design intellectual materials based on film composites. Ferroelectric composites are offered to use as the film composites. The authors discuss ferroelectric composites of different structures. Sensors and intellectual materials on the basis of the obtained composites are considered.

  17. Perspectives of development of ceramic materials with luminescent applications

    International Nuclear Information System (INIS)

    The science and technology of materials believes and it applies the knowledge that allow to relate the composition, it structures and the one processed with those properties that those they make capable for each one of the applications. The ceramic materials are inorganic materials not metallic, constituted by metallic elements and not metallic. In general, they usually behave, as good insulating electric and thermal due to the absence of conductive electrons. Usually, they possess relatively high coalition temperatures and, also, a chemical stability relatively high. Due to these properties, they are indispensable for many of those designs in engineering. The ceramic materials for luminescent applications are constituted typically by pure compounds (Al2O3, TiO2, SiO2 and ZrO2) or cocktails with some sludges giving as a result (Al2O3:TR, TiO2:Eu, Si:ZrO2, ZrO2:TR). Presently work describes the panorama to big features on the development of ceramic materials in the CICATA Unit it would Bequeath, which can be characterized by the photoluminescence techniques and thermoluminescence mainly. (Author)

  18. New approach to design of ceramic/polymer material compounds

    Science.gov (United States)

    Todt, A.; Nestler, D.; Trautmann, M.; Wagner, G.

    2016-03-01

    The damage tolerance of carbon fibre-reinforced ceramic-matrix composite materials depends on their porosity and can be rather significant. Complex structures are difficult to produce. The integration of simple geometric structures of ceramic-matrix composite materials in complex polymer-based hybrid structures is a possible approach of realising those structures. These hybrid material compounds, produced in a cost-efficient way, combine the different advantages of the individual components in one hybrid material compound. In addition the individual parts can be designed to fit a specific application and the resulting forces. All these different advantages result in a significant reduction of not only the production costs and the production time, but also opens up new areas of application, such as the large-scale production of wear-resistant and chemically inert, energy dampening components for reactors or in areas of medicine. The low wettability of the ceramic component however is a disadvantage of this approach. During the course of this contribution, different C/C composite materials with a specific porosity were produced, while adjusting the resin/hardening agent-ratio, as well as the processing parameters. After the production, different penetration tests were conducted with a polymer component. The final part of the article is comprised of the microstructural analysis and the explanation of the mechanical relationships.

  19. 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

  20. Advanced ceramic materials for next-generation nuclear applications

    International Nuclear Information System (INIS)

    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

  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. MATERIAL AND ENVIRONMENTAL SUSTAINABILITY IN CERAMIC PROCESSING

    Science.gov (United States)

    Materials Characterization The density of 3124 Ferro Frit and Mason Chrome Free Black Pigment was measured to be 2.4911 g/cm3 and 5.0703 g/cm3 respectively. The single point, BET and Langmuir surface area of 3124 Ferro Frit was deter...

  3. Calcium phosphate-based ceramic and composite materials for medicine

    International Nuclear Information System (INIS)

    The topical problems in chemistry and technology of materials based on calcium phosphates aimed at both the replacement of damaged bone tissue and its regeneration are discussed. Specific features of the synthesis of nanocrystalline powders and the fabrication of ceramic implants are described. Advances in the development of porous scaffolds from resorbable and osteoconductive calcium phosphates and of hybrid composites that form the basis of bone tissue engineering are considered.

  4. Assessment of ceramic raw materials in Uganda for electrical porcelain

    OpenAIRE

    Olupot, Peter Wilberforce

    2006-01-01

    Clay, quartz and feldspar are widely available in Uganda. The location and properties of various clay deposits are reported in the literature, but little is reported on feldspar and quartz deposits. In this work an extended literature on ceramics and porcelains in particular, is documented. Samples from two deposits of feldspar and two deposits of quartz are characterised and found to possess requisite properties for making porcelain insulators. Sample porcelain bodies are made from materials...

  5. High-temperature behaviour of ceramic materials

    International Nuclear Information System (INIS)

    This volume contains 7 papers presented at the DFG Colloquium in Munich on 16 September 1991. The subjects of the individual papers are: 1) High-Temperature Failure of Gas-Phase Containing Aluminum Oxide; 2) High-Temperature Behavior of Aluminum Oxides of Different Compositions; 3) Effect of Processing Parameters on Mechanical Properties of Platelet-Reinforced Mullite Composites; 4) Tensile Creep Investigations On Silicon Nitride Materials Using a Newly Developed Tensile Creep Facility; 5) Influence of Material and Process Technological Parameters On the High-Temperature Characteristics of Gas-Pressure Sintered Silicon Nitride; 6) The Influence of Age Hardening On the Mechanical Behavior and Microstructure of Y-doped Si3N4; 7) Application of a Crack Growth Model to Silicon Nitride. (orig./MM)

  6. Manufacturing technologies for nanocomposite ceramic structural materials and coatings

    International Nuclear Information System (INIS)

    The new material class of ceramic nanocomposites, containing at least one phase in nanometric dimension, has achieved special interest in previous years. While earlier research was focused on materials science and microstructural details in laboratory scale the subject of developing suitable manufacturing technologies in technical scale is the challenge for the manufacturing engineer. The same high-performance features which make the nanocomposite materials so interesting in their properties are absolutely detrimental if it comes to production of these materials. Extreme hardness, toughness and abrasion resistance make the state of the art cutting-and-machining operations extremely cost intensive so that, from a manufacturing point of view, true near-net-shape manufacturing is mandatory to accomplish reasonable cost targets. Ceramic feedstocks with both, high solid content to reduce shrinkage and warping and stable processing conditions are required to accomplish this aim of near-net-shape processing. Stable and reproducible processing conditions, e.g. favourable rheological properties for injection moulding are essentials for the manufacturing engineer. These prerequisites of ceramic production technologies cannot be reached with pure nanopowders in the 10-20 nm range but materials with a micro-nano architecture can fulfill these requirements, using a mixture of a submicron-sized matrix in the 100-200 nm range and smaller nanosized additives in <20% content which contribute the desired functionality. By using these micro-nanocomposites near-net-shape ceramic forming technologies such as injection moulding, gel casting and slip casting have been developed which lead to high-performance materials at affordable production cost. Advanced surface technologies include nanoceramic coatings made by thermokinetic deposition processes. Modern ceramic processing, i.e. spray drying leads to fine granulated nanopowders with appropriate flowability for subsequent APS plasma or

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

    Science.gov (United States)

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

    2016-02-01

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

  8. Encapsulation of spent nuclear fuel in ceramic materials

    International Nuclear Information System (INIS)

    The international situation with regard to deposition of spent nuclear fuel is surveyed, with emphasis on encapsulation in ceramic materials. The feasibility and advantages of ceramic containers, thermodynamic stable in groundwater, are discussed as well as the possibility to ensure that stability for longevity by engineered measures. The design prerequisite are summarized and suggestions are made for a conceptual design, comprising rutile containers with stacks of coiled fuel pins. A novel technique is suggested for the homogeneous sealing of rutile containers at low temperatures. acceptable also for the fuel pin package. Key points are given for research, demonstration and verifications of the design foundations and for future improvements. Of which a few ideas are exemplified. (author)

  9. 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.)

  10. 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

  11. Contributions to the R-curve behaviour of ceramic materials

    International Nuclear Information System (INIS)

    Several ceramic materials show an increase in crack growth resistance with increasing crack extension. Especially, in case of coarse-grained alumina this ''R-curve effect'' is caused by crack-face interactions in the wake of the advancing crack. Similar effects occur for whisker reinforced ceramics. Due to the crack-face interactions so-called ''bridging stresses'' are generated which transfer forces between the two crack surfaces. A second reason for an increase of crack-growth resistance are stress-induced phase transformations in zirconia ceramics with the tetragonal phase changing to the monoclinic phase. These transformations will affect the stress field in the surroundings of crack tips. The transformation generates a crack-tip transformation zone and, due to the stress balance, also residual stresses in the whole crack region which result in a residual stress intensity factor. This additional stress intensity factor is also a reason for the R-curve behaviour. In this report both effects are outlined in detail. (orig.)

  12. The role of characterization in emerging high performance ceramic materials

    International Nuclear Information System (INIS)

    Since the early 70's research and development efforts focusing on nitride, oxynitride, and carbide based ceramic materials have created renewed optimism concerning their potential application in severe high temperature structural applications. Cost and reliability, however, still remain as major obstacles in achieving the final successful large scale utilization of these materials. The ceramics community must now devote an appreciable effort on the less ''glamorous'' areas of those needs concerned with the maturing of an emerging technology. These aspects consist of achieving demonstrated reliability in larger scale production activities. In order to accomplish this much effort should be devoted to establishing processing optimization, design property data bases, and nondestructive or semidestructive property evaluation (NPE) procedures. As reiterated recently by Stein pull factors of need and economic gain, in general, are much more important in a free market than the technologic push factors of perceived or research scale demonstration of improved performance; analogous to pulling or pushing on a rope. Therefore, there is a strong temptation during this phase of the development to ignore this aspect and to return to more fundamental work on other, less developed, emerging materials

  13. 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.

  14. Study of the Wavelength Dependence in Laser Ablation of Advanced Ceramics and Glass-Ceramic Materials in the Nanosecond Range

    OpenAIRE

    Daniel Sola; Jose I. Peña

    2013-01-01

    In this work, geometrical dimensions and ablation yields as a function of the machining method and reference position were studied when advanced ceramics and glass-ceramic materials were machined with pulsed lasers in the nanosecond range. Two laser systems, emitting at 1064 and 532 nm, were used. It was shown that the features obtained depend on whether the substrate is processed by means of pulse bursts or by grooves. In particular, when the samples were processed by grooves, machined depth...

  15. Modeling of tritium behavior in ceramic breeder materials

    International Nuclear Information System (INIS)

    Computer models are being developed to predict tritium release from candidate ceramic breeder materials for fusion reactors. Early models regarded the complex process of tritium release as being rate limited by a single slow step, usually taken to be tritium diffusion. These models were unable to explain much of the experimental data. We have developed a more comprehensive model which considers diffusion and desorption from the grain surface. In developing this model we found that it was necessary to include the details of the surface phenomena in order to explain the results from recent tritium release experiments. A diffusion-desorption model with a desorption activation energy which is dependent on the surface coverage was developed. This model provided excellent agreement with the results from the CRITIC tritium release experiment. Since evidence suggests that other ceramic breeder materials have desorption activation energies which are dependent on surface coverage, it is important that these variations in activation energy be included in a model for tritium release. 17 refs., 12 figs

  16. Understanding and control of optical performance from ceramic materials

    International Nuclear Information System (INIS)

    This report summarizes a two-year Laboratory-Directed Research and Development (LDRD) program to gain understanding and control of the important parameters which govern the optical performance of rare-earth (RE) doped ceramics. This LDRD developed the capability to determine stable atomic arrangements in RE doped alumina using local density functional theory, and to model the luminescence from RE-doped alumina using molecular dynamic simulations combined with crystal-field calculations. Local structural features for different phases of alumina were examined experimentally by comparing their photoluminescence spectra and the atomic arrangement of the amorphous phase was determined to be similar to that of the gamma phase. The luminescence lifetimes were correlated to these differences in the local structure. The design of both high and low-phonon energy host materials was demonstrated through the growth of Er-doped aluminum oxide and lanthanum oxide. Multicomponent structures of rare-earth doped telluride glass in an alumina and silica matrix were also prepared. Finally, the optical performance of Er-doped alumina was determined as a function of hydrogen content in the host matrix. This LDRD is the groundwork for future experimentation to understand the effects of ionizing radiation on the optical properties of RE-doped ceramic materials used in space and other radiation environments

  17. Modeling of tritium behavior in ceramic breeder materials

    International Nuclear Information System (INIS)

    The model described in this paper considers diffusion and desorption as the rate-controlling mechanisms for tritium release from a ceramic breeder material. This model was used to predict the tritium release from samples of Li2SiO3 and LiAlO2, given the temperature history of the samples. The diffusion-desorption model did a better job of predicting the tritium release for these samples under pure helium purge gas than did a pure diffusion model using the best values for the diffusivity of these materials available. The activation energies of desorption found from the best fit of the predicted tritium release to the observed release were 105-108 kJ/mol for Li2SiO3 and 85.7 kJ/mol for LiAlO2. These values are in fair agreement with activation energies reported in the literature. 13 refs., 6 figs

  18. On modelling of microwave heating of a ceramic material

    International Nuclear Information System (INIS)

    A simple model is proposed and tested for simulations of ceramic processing by microwave heating. The model is based on a piecewise constant approximation of the material properties and makes it possible to separate and analyse different effects caused by the sample shape and the dependence of the material properties on temperature. Specifically, the simulation results demonstrate that microwave heating of an alumina sample can be very sensitive to a variation of its dielectric constant with temperature. For different geometries, there is a similarity in the dependences of the thermal state characteristics (temperature drop across the sample, amount of dissipated power and electric field amplitude at the sample centre) on maximal temperature. It is shown also that a temperature drop between the sample centre and surface can be strongly enhanced in the case of a spherical sample irradiated symmetrically by microwaves

  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. Application of Technogenic-Raw Material and Burning Out Additive in Composite Ceramic System

    OpenAIRE

    Viktor KIZINIEVIČ; Ramunė ŽURAUSKIENĖ; Kizinievič, Olga; Liudas TUMONIS; Rimvydas ŽURAUSKAS

    2012-01-01

    The investigation of the composite ceramic system containing easily fusible hydro-micous clay, technogenic finely dispersed raw material, and burning out waste additive is presented in the article. The properties of the raw materials used are described in the paper. The obtained ceramic bodies were burned at 1000 °C and 1050 °C temperatures, keeping at the highest burning temperature for 4 h. The analysis of physical-mechanical properties of composite ceramics (density, compressive strength, ...

  1. Bioeutectic: a new ceramic material for human bone replacement.

    Science.gov (United States)

    De Aza, P N; Guitián, F; De Aza, S

    1997-10-01

    In the present work, a new way of obtaining bioactive ceramic materials with eutectic morphology is presented. To this purpose the binary system wollastonite-tricalcium phosphate was selected, taking into account the different bioactivity behaviour of both phases. The material is formed by quasi-spherical colonies composed of alternating radial lamellae of wollastonite and tricalcium phosphate. In in vitro experiments the material presents a high reactivity, with the formation of two well-differentiated zones of hydroxyapatite, one formed by alteration of the eutectic material with solution of the wollastonite into the simulated body fluid and subsequent pseudomorphic transformation of the tricalcium phosphate into hydroxyapatite, and the other, in the last stages of the experiments, by deposition of hydroxyapatite onto the surface of the material. The hydroxyapatite morphology, formed at the beginning of the reaction, is similar to that of porous bone. The method used opens the opportunity to develop a new family of bioactive materials with different constituents, binary or ternary, for which the authors propose the general name of bioeutectics. PMID:9307217

  2. An optical coherence tomography investigation of materials defects in ceramic fixed partial dental prostheses

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda; Hughes, Michael; Bradu, Adrian; Todea, Carmen; Rominu, Mihai; Laissue, Philippe L.; Podoleanu, Adrian Gh.

    2008-04-01

    Metal ceramic and integral ceramic fixed partial prostheses are mainly used in the frontal part of the dental arch because for esthetics reasons. The masticatory stress may induce fractures of the bridges. There are several factors that are associated with the stress state created in ceramic restorations, including: thickness of ceramic layers, mechanical properties of the materials, elastic modulus of the supporting substrate material, direction, magnitude and frequency of applied load, size and location of occlusal contact areas, residual stresses induced by processing or pores, restoration-cement interfacial defects and environmental defects. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of optical coherence tomography (OCT) in detection and analysis of possible material defects in metal-ceramic and integral ceramic fixed partial dentures.

  3. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending December 31, 1982

    International Nuclear Information System (INIS)

    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

  4. New toughening concepts for ceramic composites from rigid natural materials.

    Science.gov (United States)

    Mayer, George

    2011-07-01

    The mechanisms underlying the toughening in rigid natural composites exhibited by the concentric cylindrical composites of spicules of hexactinellid sponges, and by the nacre (brick-and-mortar) structure of mollusks such as Haliotis rufescens (red abalone), as well as the crossed-lamellar structure of Strombus gigas (queen conch) show commonalities in the manner in which toughening takes place. It is proposed that crack diversion, a new kind of crack bridging, resulting in retardation of delamination, creation of new surface areas, and other energy-dissipating mechanisms occur in both natural systems. However, these are generally different from the toughening mechanisms that are utilized for other classes of structural materials. Complementary to those mechanisms found in rigid natural ceramic/organic composites, special architectures and thin viscoelastic organic layers have been found to play controlling roles in energy dissipation in these structures. PMID:21565715

  5. Dynamic material properties and terminal ballistic behaviour of shock-loaded silicon-nitride ceramics

    International Nuclear Information System (INIS)

    The dynamic properties and microscopic material structure of shock loaded Silicon-Nitride ceramics of two different densities have been investigated by means of the planar plate impact and VISAR technique. In addition the terminal ballistic behaviour of both ceramics has been determined. The combined results of the tests performed suggest an important influence of the microstructure on the terminal ballistic behaviour and thus on the ceramics protection capability against impact processes. (orig.)

  6. Composite materials based on porous ceramic preform infiltrated by aluminium alloy

    OpenAIRE

    Nagel, A.; A. J. Nowak; M. Kremzer; L.A. Dobrzański

    2007-01-01

    Purpose: The goal of this project is the optimization of manufacturing technology of the ceramic preforms basedon Al2O3 powder manufactured by the pressure infiltration method with liquid metal alloy.Design/methodology/approach: Ceramic preforms were manufactured by the method of sintering of ceramicpowder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the forming factor ofthe structure of canals and pores inside the ceramic agglomerated framework the carbon fibers...

  7. The Influence of Tool Composite's Structure During Process of Diamond Grinding of Ceramic Materials

    OpenAIRE

    Gawlik Józef; Niemczewska-Wójcik Magdalena; Krajewska Joanna; Sokhan Serghej V.; Paščenko E.A.; Žuk T.S.

    2014-01-01

    This paper presents the results of the tests performed during the grinding process of the ceramic materials: – polycrystalline ceramics (Zirconium ZrO2) and mono-crystalline ceramics (sapphire α-Al2O3) by the diamond tools. Studies have shown that the concentration (thickening) of the tool composite changes the tool's pore structure when using suitable wetted adamantine additives. Such modified composite has positive impact on tribological properties of the subsurface layer of the machined co...

  8. Electrophoretically prepared hybrid materials for biopolymer hydrogel and layered ceramic nanoparticles

    OpenAIRE

    Gwak, Gyeong-Hyeon; Choi, Ae-Jin; Bae, Yeoung-Seuk; Choi, Hyun-Jin; Oh, Jae-Min

    2016-01-01

    Background In order to obtain biomaterials with controllable physicochemical properties, hybrid biomaterials composed of biocompatible biopolymers and ceramic nanoparticles have attracted interests. In this study, we prepared biopolymer/ceramic hybrids consisting of various natural biopolymers and layered double hydroxide (LDH) ceramic nanoparticles via an electrophoretic method. We studied the structures and controlled-release properties of these materials. Results and discussion X-ray diffr...

  9. Development of manufacturing technologies for hard optical ceramic materials

    Science.gov (United States)

    Fess, Edward; DeFisher, Scott; Cahill, Mike; Wolfs, Frank

    2014-05-01

    Hard ceramic optical materials such as sapphire, ALON, Spinel, or PCA can present a significant challenge in manufacturing precision optical components due to their tough mechanical properties. These are also the same mechanical properties that make them desirable materials when used in harsh environments. Premature tool wear or tool loading during the grinding process is a common result of these tough mechanical properties. Another challenge is the requirement to create geometries that conform to the platforms they reside in, but still achieve optical window tolerances for wavefront. These shapes can be complex and require new technologies to control sub aperture finishing techniques in a deterministic fashion. In this paper we will present three technologies developed at OptiPro Systems to address the challenges associated with these materials and complex geometries. The technologies presented will show how Ultrasonic grinding can reduce grinding load by up to 50%, UltraForm Finishing (UFF) and UltraSmooth Finishing (USF) technologies can accurately figure and finish these shapes, and how all of them can be controlled deterministically, with utilizing metrology feedback, by a new Computer Aided Manufacturing (CAM) software package developed by OptiPro called ProSurf.

  10. Histological evaluation of bone response to bioactive ceramics as graft material in rats

    Directory of Open Access Journals (Sweden)

    Kršljak Elena

    2005-01-01

    Full Text Available This experimental study was carried out on 35 Albino Wister rats Artificially created bone defects were grafted with bioactive ceramic materials or control material. Histological analysis was preformed 8 weeks and 6 months after the implantation. The results revealed that bone regeneration occurred in defects treated with bioactive ceramic materials while in the defects treated with the control material signs of tissue rejection were present. As stated before, it could be concluded that bioactive ceramics can be recommended as bone substitutes in orthopedic surgery and dentistry.

  11. Functionally Graded Materials using Plasma Spray with Nano Structured Ceramic

    International Nuclear Information System (INIS)

    In this paper, nano structured FGM was fabricated using DC plasma spray technique. Nano structured and micro structured powder were used as the feeding powder with steel substrate. The spray parameters was optimized and characterisation of nano-ceramic FGM and micro-ceramic FGM were done using bending test and micro-hardness test. Experimental results have shown that the nano-structured FGM exhibit 20% improvement flexure strength and 10% in hardness. A comparison was made between sintered micro ceramic tile and nano ceramic FGM using simple drop test method.

  12. Development of new ceramic materials from the waste of serpentinite and red clay

    International Nuclear Information System (INIS)

    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)

  13. Thermoluminescence study of materials (natural minerals) used in ceramic tiles industry

    International Nuclear Information System (INIS)

    Mother earth is giving many materials in the natural form as well as in mineral form. Among them the marbles, granites and other variety of slabs for house hold flooring purposes. The people demand for variety of flooring materials leads to develop various types of ceramic tile. In India ceramic tiles industry is one of the fast growing one. More than two hundred units are manufacturing the ceramic tiles situated around Morbi, Rajkot, Gujarat, India. The basic raw materials required for manufacturing the various types of ceramic tiles are natural minerals. The following are the minerals used to manufacture the ceramic tiles i.e. quartz, feldspar, zircon, china clay, talc, grok, Aluminum oxide etc.,

  14. Energy Materials Coordinating Committee (EMACC) contractors meeting on problems and opportunities in structural ceramics

    International Nuclear Information System (INIS)

    This report consists mainly of viewographs and summaries of DOE and other programs on structural ceramics. Applications include heat engines, fusion reactors, solar absorbers, heat exchangers, coal conversion, turbines, material substitution, etc. Research centers and their capabilities are described. Panel discussions on fabrication reliability, market, ceramic producers and engine manufacturers, and conclusions are summarized

  15. Ceramics for Molten Materials Containment, Transfer and Handling on the Lunar Surface

    Science.gov (United States)

    Standish, Evan; Stefanescu, Doru M.; Curreri, Peter A.

    2009-01-01

    As part of a project on Molten Materials Transfer and Handling on the Lunar Surface, molten materials containment samples of various ceramics were tested to determine their performance in contact with a melt of lunar regolith simulant. The test temperature was 1600 C with contact times ranging from 0 to 12 hours. Regolith simulant was pressed into cylinders with the approximate dimensions of 1.25 dia x 1.25cm height and then melted on ceramic substrates. The regolith-ceramic interface was examined after processing to determine the melt/ceramic interaction. It was found that the molten regolith wetted all oxide ceramics tested extremely well which resulted in chemical reaction between the materials in each case. Alumina substrates were identified which withstood contact at the operating temperature of a molten regolith electrolysis cell (1600 C) for eight hours with little interaction or deformation. This represents an improvement over alumina grades currently in use and will provide a lifetime adequate for electrolysis experiments lasting 24 hours or more. Two types of non-oxide ceramics were also tested. It was found that they interacted to a limited degree with the melt resulting in little corrosion. These ceramics, Sic and BN, were not wetted as well as the oxides by the melt, and so remain possible materials for molten regolith handling. Tests wing longer holding periods and larger volumes of regolith are necessary to determine the ultimate performance of the tested ceramics.

  16. Prediction of the functional properties of ceramic materials from composition using artificial neural networks

    OpenAIRE

    Scott, D. J.; Coveney, P. V.; Kilner, J. A.; Rossiny, J. C. H.; Alford, N. Mc N.

    2007-01-01

    We describe the development of artificial neural networks (ANN) for the prediction of the properties of ceramic materials. The ceramics studied here include polycrystalline, inorganic, non-metallic materials and are investigated on the basis of their dielectric and ionic properties. Dielectric materials are of interest in telecommunication applications where they are used in tuning and filtering equipment. Ionic and mixed conductors are the subjects of a concerted effort in the search for new...

  17. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending June 30, 1984

    International Nuclear Information System (INIS)

    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

  18. Composite materials based on porous ceramic preform infiltrated by aluminium alloy

    Directory of Open Access Journals (Sweden)

    A. Nagel

    2007-01-01

    Full Text Available Purpose: The goal of this project is the optimization of manufacturing technology of the ceramic preforms basedon Al2O3 powder manufactured by the pressure infiltration method with liquid metal alloy.Design/methodology/approach: Ceramic preforms were manufactured by the method of sintering of ceramicpowder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the forming factor ofthe structure of canals and pores inside the ceramic agglomerated framework the carbon fibers Sigrafil C10M250 UNS were used. Then ceramic preforms were infiltrated with liquid EN AC – AlSi12 aluminum alloy.Stereological and structure investigations of obtained composite materials were made on light microscope.Findings: It was proved that developed technology of manufacturing of composite materials with the pore ceramicAl2O3 infiltration ensures expected structure and can be used in practice.Practical implications: The developed technology allows to obtain method’s elements locally reinforced andcomposite materials with precise shape mapping.Originality/value: The received results show the possibility of obtaining the new composite materials being thecheaper alternative for other materials based on the ceramic fibers.

  19. 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.

  20. The research of ceramic materials for applications in the glass industry including microwave heating techniques

    Science.gov (United States)

    Kogut, K.; Kasprzyk, K.; Zboromirska-Wnukiewicz, B.; Ruziewicz, T.

    2016-02-01

    The melting of a glass is a very energy-intensive process. Selection of energy sources, the heating technique and the method of heating recovery are a fundamental issue from the furnace design point of view of and economic effectiveness of the process. In these processes the problem constitutes the lack of the appropriate ceramic materials that would meet the requirements. In this work the standard ceramic materials were examined and verified. The possibilities of application of microwave techniques were evaluated. In addition the requirements regarding the parameters of new ceramic materials applied for microwave technologies were determined.

  1. Ceramic materials based on modified pyrogenic titanium dioxide and titanium-silica

    International Nuclear Information System (INIS)

    Ceramic materials based on modified titanium dioxide and titanium-silica are obtained. Method for modification of titanium dioxide and titanium-silica by palladium additions in the process of flame, hydrolysis of titanium, tetrachloride or silicon tetrachloride mixture with titanium tetrachloride is developed. The above method makes it possible to modify already formed particles of the final products in the reactor cooling zone, which does not effect their size and where by the whole palladium is on the surface of the ceramic material. A series of textolite is prepared on the basis of the developed ceramic materials and their metallization is performed

  2. 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.

  3. Residual stress analysis of metal/ceramic functionally graded materials

    International Nuclear Information System (INIS)

    It is very difficult to join a metal and a ceramic film directly, because the difference in their coefficients of thermal expansion is so large that cracks may occur in the film or a delamination may occur in an interface. A functionally graded material (FGM) is usual to relax an abrupt change in mechanical and/or physical properties at an interface of joining. We prepared the Fe/Al2O3 FGM consisting five layers from iron to Al2O3 by spark plasma sintering (SPS). Residual stresses in each layer of FGM were measured by RESA in order to investigate the best production condition of FGM. The following results were obtained from the residual stress measurement in FGM.1. Residual stresses in all parts of Fe were tensile and increased with decreasing the volume fraction of Fe.2. Residual stresses in all parts of Al2O3 were compression and increased with decreasing the volume fraction of Al2O3. The difference in an average internal stress was large in the part of Fe 20%-Al2O3 80%. (author)

  4. High Efficiency Axial Deep Creep-Feed Grinding Machining Technology of Engineering Ceramics Materials

    Institute of Scientific and Technical Information of China (English)

    GUO Fang; ZHANG Baoguo; LU Hong; TIAN Xinli; WANG Jianquan; LI Fuqiang

    2012-01-01

    Axial deep creep-feed grinding machining technology is a high efficiency process method of engineering ceramics materials,which is an original method to process the cylindrical ceramics materials or hole along its axis.The analysis of axial force and edge fracture proved the cutting thickness and feed rate could be more than 5-10 mm and 200 mm/min respectively in once process,and realized high efficiency,low-cost process of engineering ceramics materials.Compared with high speed-deep grinding machining,this method is also a high efficiency machining technology of engineering ceramics materials as well as with low cost.In addition,removal mechanism analyses showed that both median/radial cracks and lateral cracks appeared in the part to be removed,and the processed part is seldom destroyed,only by adjusting the axial force to control the length of transverse cracks.

  5. Newly developed foam ceramic body shows promise as thermal insulation material at 3000 deg F

    Science.gov (United States)

    Blocker, E. W.; Paul, R. D.

    1967-01-01

    Optimized zirconia foam ceramic body shows promise for use as a thermal insulation material. The insulating media displays low density and thermal conductivity, good thermal shock resistance, high melting point, and mechanical strength.

  6. Solid-State Ceramic Laser Material for Remote Sensing of Ozone Using Nd:Yttria Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In Phase II we will develop transparent Nd:Yttria ceramic laser materials that can operate at 914 nm and 946 nm suitable for applications in ozone LIDAR systems. We...

  7. Silicon nitride ceramic material having an in-situ continuous gradient function, process for manufacture, properties and applications thereof

    OpenAIRE

    Belmonte, Manuel; González Julián, Jesús; Miranzo López, Pilar; Osendi, María Isabel

    2008-01-01

    [EN] The present invention relates to a silicon mitride ceramic material having a continuous gradient in the microstructural characteristics thereof and in the properties thereof, from one extremity to the other of the ceramic component. Furthermore a method is described for the manufacture in situ of said ceramic materials having a gradient function from a single homogenous composition of ceramic powders and employing a sintering process through electric discharge modifying the temperatu...

  8. Compact pulse forming line using barium titanate ceramic material

    Science.gov (United States)

    Kumar Sharma, Surender; Deb, P.; Shukla, R.; Prabaharan, T.; Shyam, A.

    2011-11-01

    Ceramic material has very high relative permittivity, so compact pulse forming line can be made using these materials. Barium titanate (BaTiO3) has a relative permittivity of 1200 so it is used for making compact pulse forming line (PFL). Barium titanate also has piezoelectric effects so it cracks during high voltages discharges due to stresses developed in it. Barium titanate is mixed with rubber which absorbs the piezoelectric stresses when the PFL is charged and regain its original shape after the discharge. A composite mixture of barium titanate with the neoprene rubber is prepared. The relative permittivity of the composite mixture is measured to be 85. A coaxial pulse forming line of inner diameter 120 mm, outer diameter 240 mm, and length 350 mm is made and the composite mixture of barium titanate and neoprene rubber is filled between the inner and outer cylinders. The PFL is charged up to 120 kV and discharged into 5 Ω load. The voltage pulse of 70 kV, 21 ns is measured across the load. The conventional PFL is made up of oil or plastics dielectrics with the relative permittivity of 2-10 [D. R. Linde, CRC Handbook of Chemistry and Physics, 90th ed. (CRC, 2009); Xia et al., Rev. Sci. Instrum. 79, 086113 (2008); Yang et al., Rev. Sci. Instrum. 81, 43303 (2010)], which increases the length of PFL. We have reported the compactness in length achieved due to increase in relative permittivity of composite mixture by adding barium titanate in neoprene rubber.

  9. Compact pulse forming line using barium titanate ceramic material.

    Science.gov (United States)

    Kumar Sharma, Surender; Deb, P; Shukla, R; Prabaharan, T; Shyam, A

    2011-11-01

    Ceramic material has very high relative permittivity, so compact pulse forming line can be made using these materials. Barium titanate (BaTiO(3)) has a relative permittivity of 1200 so it is used for making compact pulse forming line (PFL). Barium titanate also has piezoelectric effects so it cracks during high voltages discharges due to stresses developed in it. Barium titanate is mixed with rubber which absorbs the piezoelectric stresses when the PFL is charged and regain its original shape after the discharge. A composite mixture of barium titanate with the neoprene rubber is prepared. The relative permittivity of the composite mixture is measured to be 85. A coaxial pulse forming line of inner diameter 120 mm, outer diameter 240 mm, and length 350 mm is made and the composite mixture of barium titanate and neoprene rubber is filled between the inner and outer cylinders. The PFL is charged up to 120 kV and discharged into 5 Ω load. The voltage pulse of 70 kV, 21 ns is measured across the load. The conventional PFL is made up of oil or plastics dielectrics with the relative permittivity of 2-10 [D. R. Linde, CRC Handbook of Chemistry and Physics, 90th ed. (CRC, 2009); Xia et al., Rev. Sci. Instrum. 79, 086113 (2008); Yang et al., Rev. Sci. Instrum. 81, 43303 (2010)], which increases the length of PFL. We have reported the compactness in length achieved due to increase in relative permittivity of composite mixture by adding barium titanate in neoprene rubber. PMID:22129008

  10. Capsulation of moldings made from silicon ceramic material

    Science.gov (United States)

    Rossmann, A.; Schweitzer, K.; Huether, W.

    1985-01-01

    Ceramic articles are potted for hot isostatic pressing by porous glass and/or ceramic coating which is sintered to a pressure-tight coating in vacuo. Thus, a powdered SiO2 glass mixture with saturated alcohol sterin is sprayed on a SI3N4 ceramic, dried, introduced into the press which is evacuated to less than 0.013 mbar and heated to approximately 1200 C to drive off the organic binder and leave a powdered glass coating on the ceramic. The coating is sintered by heating to approximately 1200 C for 0.5 to 2 hours and forms a tight gass-impermeable layer. The press is heated to approximately 1700 C at 1000-300 bar and isostatic pressing is performed in the conventional manner.

  11. Effect of carbon on wettability and interface reaction between melt superalloy and ceramic material

    OpenAIRE

    Chen Xiaoyan; Zhou Yizhou; Jin Tao; Sun Xiaofeng

    2014-01-01

    Effect of C on wettability and interface reaction between a nickel based superalloy and ceramic material was investigated by using a sessile drop method. It was found that the content of C in the alloy is able to influence the wettability and interface reaction. Alloys with C content lower than 0.1wt.% are stable on ceramic material and no interface reaction generates at the alloy-ceramic interface. However, when C content is higher than 0.1wt.%, the interface reaction occurs and the wetting ...

  12. Raw-materials mixtures from waste of the coal industry for production of ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Galpern, E.I. [Scientific-Manufacturing Enterprise ``Ceramics``, Donetsk (Ukraine); Pashchenko, L.V. [Inst. of Physical, Organic and Coal Chemistry of NASU, Donetsk (Ukraine)

    1998-09-01

    The liquidation of waste dumps on the surface of mining enterprises and realization of measures by environment protection of air and aquatic basins are connected to the complex processing of mining mass. The main directions of utilization of mining rocks and coal wastes realized in Ukraine industry are: - filling of mines worked-out area by grouting solutions; - ceramic brick, porous filling materials and binding materials production; - road-making, construction of hydrostructures and industrial objects; - output of concrete items predominantly for using in mining conditions. The peculiarity of wastes using in above-mentioned fields is the possibility of their mass application in quantities commensurable with valumes of their yields. The experience of enterprises work which process mining rocks into building materials by burning method (ceramic brick, porous aggregates of concretes as aggloporite, expanded clay aggregate) has shown that unconstant and, as the rule, exceeding norms content of carbon and sulphur in the rock results to deterioration of products quality and technological factors of production. Unstability of carbon content in raw material makes the burning process hardly operated. Obtained products having residual carbon in the view of coke residue are often characterized by lower physical-mechanical characteristics. (orig./SR)

  13. Modified PZT ceramics as a material that can be used in micromechatronics

    Science.gov (United States)

    Zachariasz, Radosław; Bochenek, Dariusz

    2015-11-01

    Results on investigations of the PZT type ceramics with the following chemical composition: Pb0.94Sr0.06(Zr0.50 Ti0.50)0.99 Cr0.01O3 (PSZTC) which belongs to a group of multicomponent ceramic materials obtained on basis of the PZT type solid solution, are presented in this work. Ceramics PSZTC was obtained by a free sintering method under the following conditions: Tsint = 1250 °C and tsint = 2 h. Ceramic compacts of specimens for the sintering process were made from the ceramic mass consisting of a mixture of the synthesized PSZTC powder and 3% polyvinyl alcohol while wet. The PSZTC ceramic specimens were subjected to poling by two methods: low temperature and high temperature. On the basis of the examinations made it has been found that the ceramics obtained belongs to ferroelectric-hard materials and that is why it may be used to build resonators, filters and ultrasonic transducers. Contribution to the Topical Issue "Materials for Dielectric Applications" edited by Maciej Jaroszewski and Sabu Thomas.

  14. Fabrication and characterization of glass–ceramics materials developed from steel slag waste

    International Nuclear Information System (INIS)

    Highlights: ► Steelmaking slag (SS) is one of the most common industrial wastes. ► Glass–ceramics produced from SS is observed to have good properties. ► A large volume of raw SS can be recycled. ► The utilization of SS could reduce solid waste pollution. -- Abstract: In this study, glass–ceramic materials were produced from SS (steel slag) obtained from Wuhan Iron and Steel Corporation in China. The amount of SS used in glass batch was about 31–41 wt.% of the total batch mixture. On basis of differential thermal analysis (DTA) results, the nucleation and crystallization temperature of the parent glass samples were identified, respectively. X-ray diffraction (XRD) revealed that multiple crystalline phases coexisted in the glass–ceramics, and the main crystalline phase was wollastonite (CaSiO3). SEM observation indicated that there was an increase in the amount of crystalline phase in the glass–ceramics when the CaO content and crystallization time increased. It was also found that the glass–ceramics with fine microstructure enhance mechanical properties and erosion wear resistance. The obtained glass–ceramics showed a maximum bending strength of 145.6 MPa and very nice wear resistance. Therefore, it is feasible to produce nucleated glass–ceramics materials for building and decorative materials from SS.

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

    Science.gov (United States)

    Salem, Jonathan A.; Jenkins, Michael G.

    2003-01-01

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

  16. Compaction of Ceramic Microspheres, Spherical Molybdenum Powder and Other Materials to 3 GPa

    International Nuclear Information System (INIS)

    Pressure-volume relationships were measured at room temperature for eight granular materials and one specimen of epoxy foam. The granular materials included hollow ceramic microspheres, spherical molybdenum powder, Ottawa sand, aluminum, copper, titanium and silicon carbide powders and glassy carbon spheres. Measurements were made to 0.9 GPa in a liquid medium press for all of the granular materials and to 3 GPa in a solid medium press for the ceramic microspheres and molybdenum powder. A single specimen of epoxy foam was compressed to 30 MPa in the liquid medium press. Bulk moduli were calculated as a function of pressure for the ceramic microspheres, the molybdenum powder and three other granular materials. The energy expended in compacting the granular materials was determined by numerically integrating pressure-volume curves. More energy was expended per unit volume in compacting the molybdenum powder to 1 GPa than for the other materials, but compaction of the ceramic microspheres required more energy per gram due to their very low initial density. The merge pressure, the pressure at which all porosity is removed, was estimated for each material by plotting porosity against pressure on a semi-log plot. The pressure-volume curves were then extrapolated to the predicted merge pressures and numerically integrated to estimate the energy required to reach full density for each material. The results suggest that the glassy carbon spheres and the ceramic microspheres would require more energy than the other materials to attain full density

  17. Archaeometry of ceramic materials: an evaluation of the andalusian experience

    Directory of Open Access Journals (Sweden)

    Cordero Ruiz, Tomás

    2006-06-01

    Full Text Available This paper assesses the impact that the introduction of scientific methods for materials characterisation (conventionally grouped under the label of Archaeometry has had in the methodological configuration of Spanish archaeology over the last two decades. This is achieved through a bibliometric study of publications dealing with characterisation of archaeological ceramics from Andalucía (southern Spain. The variables handled in this study include aspects such as the number of sampled sites and items, their geographical provenance, the chronological and functional dimensions of the archaeological contexts they were taken from as well as the analytical techniques employed in their study.

    Este artículo intenta valorar el impacto que la introducción de métodos de caracterización de materiales procedentes de la física y la química (y agrupados habitualmente bajo la denominación genérica de Arqueometría ha tenido en la configuración metodológica de la investigación arqueológica de nuestro país durante las últimas dos décadas. Para ello se realiza un análisis bibliométrico de un ámbito específico de la aplicación de las técnicas arqueométricas, cual es el de la caracterización de materiales cerámicos dentro de la Arqueología andaluza. Las variables tenidas en cuenta incluyen aspectos tales como la cantidad de sitios arqueológicos muestreados y de muestras analizadas, su procedencia geográfica, los contextos cronológicos y funcionales de los que las muestras fueron tomadas y las técnicas analíticas empleadas.

  18. Effect of carbon on wettability and interface reaction between melt superalloy and ceramic material

    Directory of Open Access Journals (Sweden)

    Chen Xiaoyan

    2014-01-01

    Full Text Available Effect of C on wettability and interface reaction between a nickel based superalloy and ceramic material was investigated by using a sessile drop method. It was found that the content of C in the alloy is able to influence the wettability and interface reaction. Alloys with C content lower than 0.1wt.% are stable on ceramic material and no interface reaction generates at the alloy-ceramic interface. However, when C content is higher than 0.1wt.%, the interface reaction occurs and the wetting angle decreases quickly. The product of interface reaction is discontinuous and composed of 9Al2O3 ⋅Cr2O3. Such result indicates that Cr in the alloy is impossible to react with the ceramic material and form Cr2O3 without the assistance of C. It is suggested that C in the alloy deoxidizes SiO2 in the ceramic material and produces SiO and CO. SiO is unstable and it can release active O atom at the interface. Cr at the interface combines with free O atom and forms Cr2O3. Al2O3 in the ceramic material and Cr2O3 finally forms 9Al2O3 ⋅Cr2O3.

  19. Radioactivity and associated radiation hazards in ceramic raw materials and end products

    International Nuclear Information System (INIS)

    Studies have been planned to obtain activity and associated radiation hazards in ceramic raw materials (quartz, feldspar, clay, zircon, kaolin, grog, alumina bauxite, baddeleyite, masse, dolomite and red mud) and end products (ceramic brick, glazed ceramic wall and floor tiles) as the activity concentrations of uranium, thorium and potassium vary from material to material. The primordial radionuclides in ceramic raw materials and end products are one of the sources of radiation hazard in dwellings made of these materials. By the determination of the activity level in these materials, the indoor radiological hazard to human health can be assessed. This is an important precautionary measure whenever the dose rate is found to be above the recommended limits. The aim of this work was to measure the activity concentration of 226Ra, 232Th and 40K in ceramic raw materials and end products. The activity of these materials has been measured using a gamma-ray spectrometry, which contains an NaI(Tl) detector connected to multichannel analyser (MCA). Radium equivalent activity, alpha-gamma indices and radiation hazard indices associated with the natural radionuclides are calculated to assess the radiological aspects of the use of the ceramic end products as decorative or covering materials in construction sector. Results obtained were examined in the light of the relevant international legislation and guidance and compared with the results of similar studies reported in different countries. The results suggest that the use of ceramic end product samples examined in the construction of dwellings, workplace and industrial buildings is unlikely to give rise to any significant radiation exposure to the occupants. (authors)

  20. The modeling of the shock response of powdered ceramic materials

    Science.gov (United States)

    Rajendran, A. M.; Ashmawi, W. M.; Zikry, M. A.

    2006-06-01

    A two-cap constitutive model that incorporates inelastic yielding, frictional sliding, and densification was modified for shock-loading applications, and used to model shock-wave propagation of a powdered ceramic that is constrained by aluminum layers in a system, which is impacted by a flyer plate. The numerical results included analyses of the effects of shock stress amplitudes on densification, unloading behaviors, stress attenuation and dispersion, and stress and pressure distributions. An understanding of how interfacial impedances affect shock-front attenuation, dispersion, and propagation were obtained through modeling different shock-load conditions. The constitutive and computational models were validated with detailed simulations of shock-front experiments pertaining to powdered ceramics. It is shown how shock amplitude duration and rise time are related to stress evolution, and how physically limiting values result in inelastic damage. This analysis underscores how modeling with the appropriate constitutive description can provide insights on how powdered ceramics behave under impact-loading conditions.

  1. Antibacterial and mechanical properties of honeycomb ceramic materials incorporated with silver and zinc

    International Nuclear Information System (INIS)

    Highlights: • Novel application of honeycomb ceramic carrier for environmentally benign processes. • Honeycomb ceramic have antibacterial properties by doping with silver and zinc. • The foundation of honeycomb ceramic to promote the application in various fields. • Honeycomb ceramic microstructure and characterization by XRD and SEM micro-analysis. - Abstract: The antibacterial and mechanical properties of heat-resistant honeycomb ceramic materials produced from red mud industrial waste and doped with Zn and Ag are determined. Excellent antibacterial effects against Escherichia coli are obtained by the plate counting and vibration methods. When 5% and 6% Zn are added to the honeycombs doped with 0.3% Ag, the antibacterial rates reach 98.9% and 99.5%, respectively. The mechanical properties are evaluated by monitoring the bending strength, open porosity, water absorption capability, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The Zn and Ag particles are distributed uniformly in the honeycomb ceramics and the crystalline structure of the ceramic materials is not altered after Zn and Ag incorporation consequently enabling good dispersion of the antibacterial metals

  2. Reclamation of material from used ceramic moulds applied in the investment casting technology

    Directory of Open Access Journals (Sweden)

    M. Holtzer

    2010-07-01

    Full Text Available Investigations on utilisation of reclaimed materials from used ceramic moulds applied in the investment casting technology, are presented in the hereby paper. This reclaim was used as a matrix for the preparation of the test moulds. Rheological properties as well as tensile strength at a room temperature of such ceramic sands were even better than of sands made of fresh components. However, ceramic sands with a reclaimed material exhibited worse properties at higher temperatures. The second direction of utilizing the reclaim was using it as the so-called powder topping when making ceramic moulds (for the IInd and successive layers. Tensile strength values at hightemperatures of moulds made with the reclaim participation were comparable (and in some cases even higher to values of moulds made offresh components (Al2O3. These results encourage the further investigations in this field.

  3. Refractory Materials for Flame Deflector Protection System Corrosion Control: Refractory Ceramics Literature Survey

    Science.gov (United States)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark; Perusich, Stephen; Whitten, Mary C.; Trejo, David; Zidek, Jason; Sampson, Jeffrey W.; Coffman, Brekke E.

    2009-01-01

    Ceramics can be defmed as a material consisting of hard brittle properties produced from inorganic and nonmetallic minerals made by firing at high temperatures. These materials are compounds between metallic and nonmetallic elements and are either totally ionic, or predominately ionic but having some covalent character. This definition allows for a large range of materials, not all applicable to refractory applications. As this report is focused on potential ceramic materials for high temperature, aggressive exposure applications, the ceramics reviewed as part of this report will focus on refractory ceramics specifically designed and used for these applications. Ceramic materials consist of a wide variety of products. Callister (2000) 1 characterized ceramic materials into six classifications: glasses, clay products, refractories, cements, abrasives, and advanced ceramics. Figure 1 shows this classification system. This review will focus mainly on refractory ceramics and cements as in general, the other classifications are neither applicable nor economical for use in large structures such as the flame trench. Although much work has been done in advanced ceramics over the past decade or so, these materials are likely cost prohibitive and would have to be fabricated off-site, transported to the NASA facilities, and installed, which make these even less feasible. Although the authors reviewed the literature on advanced ceramic refractories 2 center dot 3 center dot 4 center dot 5 center dot 6 center dot 7 center dot 8 center dot 9 center dot 10 center dot 11 center dot 12 after the review it was concluded that these materials should not be ' the focus of this report. A review is in progress on materials and systems for prefabricated refractory ceramic panels, but this review is focusing more on typical refractory materials for prefabricated systems, which could make the system more economically feasible. Refractory ceramics are used for a wide variety of applications

  4. EXAFS and XANES analysis of plutonium and cerium edges from titanate ceramics for fissile materials disposal

    International Nuclear Information System (INIS)

    We report x-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectra from the plutonium LIII edge and XANES from the cerium LII edge in prototype titanate ceramic hosts. The titanate ceramics studied are based upon the hafnium-pyrochlore and zirconolite mineral structures and will serve as an immobilization host for surplus fissile materials, containing as much as 10 weight % fissile plutonium and 20 weight % (natural or depleted) uranium. Three ceramic formulations were studied: one employed cerium as a ''surrogate'' element, replacing both plutonium and uranium in the ceramic matrix, another formulation contained plutonium in a ''baseline'' ceramic formulation, and a third contained plutonium in a formulation representing a high-impurity plutonium stream. The cerium XANES from the surrogate ceramic clearly indicates a mixed III-IV oxidation state for the cerium. In contrast, XANES analysis of the two plutonium-bearing ceramics shows that the plutonium is present almost entirely as Pu(IV) and occupies the calcium site in the zirconolite and pyrochlore phases. The plutonium EXAFS real-space structure shows a strong second-shell peak, clearly distinct from that of PuO2, with remarkably little difference in the plutonium crystal chemistry indicated between the baseline and high-impurity formulations

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

    Science.gov (United States)

    Yashima, Masatomo

    2011-05-01

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

  6. Research study for gel precursors as glass and ceramic starting materials for space processing applications research

    Science.gov (United States)

    Downs, R. L.; Miller, W. J.

    1983-01-01

    The development of techniques for the preparation of glass and ceramic starting materials that will result in homogeneous glasses or ceramic products when melted and cooled in a containerless environment is described. Metal-organic starting materials were used to make compounds or mixtures which were then decomposed by hydrolysis reactions to the corresponding oxides. The sodium tungstate system was chosen as a model for a glass with a relatively low melting temperature. The alkoxide tungstates also have interesting optical properties. For all the compositions studied, comparison samples were prepared from inorganic starting materials and submitted to the same analyses.

  7. Potentiality of a frit waste from ceramic sector as raw material to glass-ceramic material production

    International Nuclear Information System (INIS)

    This work consists of studying the devitrification capacity of a residue from sodium-calcium frit, using the vitreous powder sintering method, which follows the traditional ceramic processing route, including a specific heat treatment to generate the appearance of crystals from the original glass phase. Initially the frit residue has been characterized by instrumental techniques such as XRF, XRD and DTA/TG. Furthermore, the chemical analysis (XRF) has allowed the prediction of devitrification potentiality of this residue by theoretical approaches represented by Gingsberg, Raschin-Tschetverikov and Lebedeva ternary diagrams. Then, this residue was subjected to traditional ceramic method, by changing the grinding time, the pressing pressure and prepared samples were obtained at different temperatures. In this part, the techniques for measuring particle size by laser diffraction and XRD and SEM to evaluate the generated crystalline phases, were applied. Finally, it has been found that this frit residue works as glass-ceramic precursor, devitrifying in wollastonite crystals as majority phase and without being subjected to the melting step of the glass-ceramic typical method. (Author)

  8. 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. PMID:27524006

  9. Process Development of Porcelain Ceramic Material with Binder Jetting Process for Dental Applications

    Science.gov (United States)

    Miyanaji, Hadi; Zhang, Shanshan; Lassell, Austin; Zandinejad, Amirali; Yang, Li

    2016-03-01

    Custom ceramic structures possess significant potentials in many applications such as dentistry and aerospace where extreme environments are present. Specifically, highly customized geometries with adequate performance are needed for various dental prostheses applications. This paper demonstrates the development of process and post-process parameters for a dental porcelain ceramic material using binder jetting additive manufacturing (AM). Various process parameters such as binder amount, drying power level, drying time and powder spread speed were studied experimentally for their effect on geometrical and mechanical characteristics of green parts. In addition, the effects of sintering and printing parameters on the qualities of the densified ceramic structures were also investigated experimentally. The results provide insights into the process-property relationships for the binder jetting AM process, and some of the challenges of the process that need to be further characterized for the successful adoption of the binder jetting technology in high quality ceramic fabrications are discussed.

  10. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

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

  12. Compatibility tests of materials for a prototype ceramic melter for defense glass-waste products

    International Nuclear Information System (INIS)

    The corrosion--erosion resistance of potential electrode and refractory materials was evaluated by static and dynamic tests in simulated glass waste. Based on corrosion--erosion behavior, thermal and electrical properties, and cost and availability, Monofrax K3 (Carborundum Co.) and Inconel 690 (International Nickel Co.) were selected as the contact refractory and electrode materials, respectively, for a prototype ceramic melter

  13. Morphologies, Processing and Properties of Ceramic Foams and Their Potential as TPS Materials

    Science.gov (United States)

    Stackpoole, Mairead; Simoes, Conan R.; Johnson, Sylvia M.

    2002-01-01

    The current research is focused on processing ceramic foams with compositions that have potential as a thermal protection material. The use of pre-ceramic polymers with the addition of sacrificial blowing agents or sacrificial fillers offers a viable approach to form either open or closed cell insulation. Our work demonstrates that this is a feasible method to form refractory ceramic foams at relatively low processing temperatures. It is possible to foam complex shapes then pyrolize the system to form a ceramic while retaining the shape of the unfired foam. Initial work focused on identifying suitable pre-ceramic polymers with desired properties such as ceramic yield and chemical make up of the pyrolysis product after firing. We focused on making foams in the Si system (Sic, Si02, Si-0-C), which is in use in current acreage TPS systems. Ceramic foams with different architectures were formed from the pyrolysis of pre-ceramic polymers at 1200 C in different atmospheres. In some systems a sacrificial polyurethane was used as the blowing agent. We have also processed foams using sacrificial fillers to introduce controlled cell sizes. Each sacrificial filler or blowing agent leads to a unique morphology. The effect of different fillers on foam morphologies and the characterization of these foams in terms of mechanical and thermal properties are presented. We have conducted preliminary arc jet testing on selected foams with the materials being exposed to typical re-entry conditions for acreage TPS and these results will be discussed. Foams processed using these approaches have bulk densities ranging from 0.15 to 0.9 g/cm3 and cell sizes ranging from 5 to 500 pm. Compression strengths ranged from 2 to 7 MPa for these systems. Finally, preliminary oxidation studies have been conducted on selected systems and will be discussed.

  14. Efficiency characterization of ceramic filtering materials used for drinking water treatment

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    For ceramic filtering materials, their adsorption capacities, purification efficiencies to remove organic compounds from drinking water, and correlation between adsorption capacities and pore structures were tested and analyzed. The results show that correlation coefficient between the specific surface area and the adsorptive amount of iodine molecule is 0.99;correlation coefficient between the pore volume and the adsorptive value of tannin molecule is 0.92. And correlation coefficient between the most probable diameter and the adsorption parameter is 1.0. A new method of morphology characterization for ceramic filtering materials was developed. Which offered a sort of standard for the evaluation on water purification efficiencies and selection of ceramic filtering materials.

  15. Development and application of ferrite materials for low temperature co-fired ceramic technology

    Science.gov (United States)

    Zhang, Huai-Wu; Li, Jie; Su, Hua; Zhou, Ting-Chuan; Long, Yang; Zheng, Zong-Liang

    2013-11-01

    Development and application of ferrite materials for low temperature co-fired ceramic (LTCC) technology are discussed, specifically addressing several typical ferrite materials such as M-type barium ferrite, NiCuZn ferrite, YIG ferrite, and lithium ferrite. In order to permit co-firing with a silver internal electrode in LTCC process, the sintering temperature of ferrite materials should be less than 950 °C. These ferrite materials are research focuses and are applied in many ways in electronics.

  16. Ceramic materials lead to underestimated DNA quantifications: a method for reliable measurements

    Directory of Open Access Journals (Sweden)

    E Piccinini

    2010-07-01

    Full Text Available In the context of investigating cell-material interactions or of material-guided generation of tissues, DNA quantification represents an elective method to precisely assess the number of cells attached or embedded within different substrates.Nonetheless, nucleic acids are known to electrostatically bind to ceramics, a class of materials commonly employed in orthopaedic implants and bone tissue engineering scaffolds. This phenomenon is expected to lead to a relevant underestimation of the DNA amount, resulting in erroneous experimental readouts. The present work aims at (i investigating the effects of DNA-ceramic bond occurrence on DNA quantification, and (ii developing a method to reliably extract and accurately quantify DNA in ceramic-containing specimens.A cell-free model was adopted to study DNA-ceramic binding, highlighting an evident DNA loss (up to 90% over a wide range of DNA/ceramic ratios (w/w. A phosphate buffer-based (800mM enzymatic extraction protocol was developed and its efficacy in terms of reliable DNA extraction and measurement was confirmed with commonly used fluorometric assays, for various ceramic substrates. The proposed buffered DNA extraction technique was validated in a cell-based experiment showing 95% DNA retrieval in a cell seeding experiment, demonstrating a 3.5-fold increase in measured DNA amount as compared to a conventional enzymatic extraction protocol.In conclusion, the proposed phosphate buffer method consistently improves the DNA extraction process assuring unbiased analysis of samples and allowing accurate and sensitive cell number quantification on ceramic containing substrates.

  17. Use of ceramic materials in waste-package systems for geologic disposal of nuclear wastes

    International Nuclear Information System (INIS)

    A study to investigate the potential use of ceramic materials as components in the waste package systems was conducted. The initial objective of the study was to screen and compare a large number of ceramic materials and identify the best materials for the proposed application. The principal method used to screen the candidates was to subject samples of each material to a series of leaching tests and to determine their relative resistance to attack by the leach solutions. A total of 14 ceramic materials, plus graphite and basalt were evaluated using three different leach solutions: demineralized water, a synthetic Hanford ground water, and a synthetic WIPP brine solution. The ceramic materials screened were Al2O3 (99%), Al2O3 (99.8%), mullite (2Al2O3.SiO2), vitreous silica (SiO2), BaTiO3, CaTiO3, CaTiSiO5, TiO2, ZrO2, ZrSiO4, Pyroceram 9617, and Marcor Code 9658 machinable glass-ceramic. Average leach rates for the materials tested were determined from analyses of the leach solutions and/or sample weight loss measurements. Because of the limited scope of the present study, evaluation of the specimens was limited to ceramographic examination. Based on an overall evaluation of the leach rate data, five of the materials tested, namely graphite, TiO2, ZrO2, and the two grades of alumina, exhibited much greater resistance to leaching than did the other materials tested. Based on all the experimental data obtained, and considering other factors such as cost, availability, fabrication technology, and mechanical and physical properties, graphite and alumina are the preferred candidates for the barrier application. The secondary choices are TiO2 and ZrO2

  18. Advanced Ceramics

    International Nuclear Information System (INIS)

    The First Florida-Brazil Seminar on Materials and the Second State Meeting about new materials in Rio de Janeiro State show the specific technical contribution in advanced ceramic sector. The others main topics discussed for the development of the country are the advanced ceramic programs the market, the national technic-scientific capacitation, the advanced ceramic patents, etc. (C.G.C.)

  19. Tritium transport and release from lithium ceramic breeder materials

    International Nuclear Information System (INIS)

    In an operating fusion reactor,, the tritium breeding blanket will reach a condition in which the tritium release rate equals the production rate. The tritium release rate must be fast enough that the tritium inventory in the blanket does not become excessive. Slow tritium release will result in a large tritium inventory, which is unacceptable from both economic and safety viewpoints As a consequence, considerable effort has been devoted to understanding the tritium release mechanism from ceramic breeders and beryllium neutron multipliers through theoretical, laboratory, and in-reactor studies. This information is being applied to the development of models for predicting tritium release for various blanket operating conditions

  20. Natural radionuclides in ceramic building materials available in Cuddalore district, Tamil Nadu, India

    International Nuclear Information System (INIS)

    The activity concentrations of radium, thorium and potassium can vary from material to material and they should be measured as the radiation is hazardous for human health. Thus, studies have been planned to obtain the radioactivity of ceramic building materials used in Cuddalore District, Tamilnadu, India. The radioactivity of some ceramic materials used in this region has been measured using a gamma-ray spectrometry, which contains an NaI(Tl) detector connected to multichannel analyzer. The specific activities of 226Ra, 232Th and 40K, from the selected ceramic building materials, were in the range of 9.89-30.75, 24.68-70.4, 117.19-415.83 Bq kg-1, respectively. The radium equivalent activity, absorbed gamma dose rate (D) and annual effective dose rate associated with the natural radionuclides are calculated to assess the radiation hazards of the natural radioactivity in the ceramic building materials. It was found that none of the results exceeds the recommended limit value. (authors)

  1. Metal-ceramic functionally gradient material for insulation pipe joint in fusion environment

    International Nuclear Information System (INIS)

    A stainless steel/ceramics/stainless steel functionally gradient material (FGM) has been developed for an integrated insulation joint of the piping system. Both sides of the joint unit are welded to the main pipes. The FGM composed of metal and ceramics is produced by a sintering process from the powder stainless steel and powder ceramics. It is a key issue to suppress the residual thermal stress generated in the sintering process. The producible conditions, e.g., the thickness of graded layer, the column diameter, the materials combination and the sintering temperature and pressure, have been established. The performance tests of FGM joint, i.e., electrical property, mechanical property, vacuum tightness property and neutron irradiation effect were carried out. The results of those tests say that the FGM joint capable of providing the electrical insulation of cooling pipes for vacuum use. (orig.)

  2. Application of Technogenic-Raw Material and Burning Out Additive in Composite Ceramic System

    Directory of Open Access Journals (Sweden)

    Olga KIZINIEVIČ

    2012-09-01

    Full Text Available The investigation of the composite ceramic system containing easily fusible hydro-micous clay, technogenic finely dispersed raw material, and burning out waste additive is presented in the article. The properties of the raw materials used are described in the paper. The obtained ceramic bodies were burned at 1000 °C and 1050 °C temperatures, keeping at the highest burning temperature for 4 h. The analysis of physical-mechanical properties of composite ceramics (density, compressive strength, water absorption, its structural parameters (effective and total open porosity, reserve of pore volume, relative wall thickness of the pores and capillaries, and X-ray diffraction analysis was performed. The interdependencies between some structural parameters are described by empirical equations. DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2443

  3. Stochastic modeling of filtrate alkalinity in water filtration devices: Transport through micro/nano porous clay based ceramic materials

    Science.gov (United States)

    Clay and plant materials such as wood are the raw materials used in manufacture of ceramic water filtration devices around the world. A step by step manufacturing procedure which includes initial mixing, molding and sintering is used. The manufactured ceramic filters have numerous pores which help i...

  4. 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.

  5. Ceramic materials lead to underestimated DNA quantifications: a method for reliable measurements

    OpenAIRE

    E Piccinini

    2010-01-01

    In the context of investigating cell-material interactions or of material-guided generation of tissues, DNA quantification represents an elective method to precisely assess the number of cells attached or embedded within different substrates.Nonetheless, nucleic acids are known to electrostatically bind to ceramics, a class of materials commonly employed in orthopaedic implants and bone tissue engineering scaffolds. This phenomenon is expected to lead to a relevant underestimation of the DNA ...

  6. Metals and Ceramics Division materials science annual progress report for period ending June 30, 1978

    International Nuclear Information System (INIS)

    Topics covered include: structure of materials, theoretical research; x-ray diffraction research; fundamental ceramics studies; preparation and synthesis of high-temperature and special service materials; physical metallurgy; grain boundary segregation and fracture; mechanisms of surface and solid-state reactions; physical properties research; superconducting materials; radiation effects; facility and technique development; nuclear microanalysis; cooperative studies with universities and other research organizations; and fundamentals of welding and joining

  7. Metals and Ceramics Division materials science annual progress report for period ending June 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J.; Peterson, S. (comps.)

    1978-09-01

    Topics covered include: structure of materials, theoretical research; x-ray diffraction research; fundamental ceramics studies; preparation and synthesis of high-temperature and special service materials; physical metallurgy; grain boundary segregation and fracture; mechanisms of surface and solid-state reactions; physical properties research; superconducting materials; radiation effects; facility and technique development; nuclear microanalysis; cooperative studies with universities and other research organizations; and fundamentals of welding and joining. (GHT)

  8. In vitro evaluation of fracture strength of zirconia restoration veneered with various ceramic materials

    OpenAIRE

    Choi, Yu-Sung; Kim, Sung-Hun; Lee, Jai-Bong; Han, Jung-Suk; Yeo, In-Sung

    2012-01-01

    PURPOSE Fracture of the veneering material of zirconia restorations frequently occurs in clinical situations. The purpose of this in vitro study was to compare the fracture strengths of zirconia crowns veneered with various ceramic materials by various techniques. MATERIALS AND METHODS A 1.2 mm, 360° chamfer preparation and occlusal reduction of 2 mm were performed on a first mandibular molar, and 45 model dies were fabricated in a titanium alloy by CAD/CAM system. Forty-five zirconia copings...

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

    International Nuclear Information System (INIS)

    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

  10. 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)

  11. Engineering spinal fusion: evaluating ceramic materials for cell based tissue engineered approaches

    NARCIS (Netherlands)

    Wilson, C.E.

    2011-01-01

    The principal aim of this thesis was to advance the development of tissue engineered posterolateral spinal fusion by investigating the potential of calcium phosphate ceramic materials to support cell based tissue engineered bone formation. This was accomplished by developing several novel model syst

  12. Standard practice for labeling ceramic art materials for chronic adverse health hazards

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice describes a procedure for developing precautionary labels for ceramic art materials and provides hazard and precautionary statements based upon knowledge that exists in the scientific and medical communities. This practice concerns those chronic adverse health hazards known to be associated with a product or product component(s), when the component(s) is present in a physical form, volume, or concentration that in the opinion of a toxicologist has the potential to produce a chronic adverse health effect(s). 1.2 This practice is intended to apply exclusively to ceramic art materials which are packaged in sizes intended for use by artists or crafts people, either individually, or in a small group or class. 1.3 This practice applies to developing precautionary labeling for ceramic art materials intended for adult usage. Conformance to this practice does not imply that ceramic art materials will necessarily be labeled adequately or safe for use by children. Labeling determinations should cons...

  13. Influence of Water Storage and Bonding Material on Bond Strength of Metallic Brackets to Ceramic.

    Science.gov (United States)

    Costa, Ana Rosa; Correr, Américo Bortolazzo; Consani, Simonides; Giorgi, Maria Cecília Caldas; Vedovello, Silvia Amélia; Vedovello Filho, Mário; Santos, Eduardo Cesar Almada; Correr-Sobrinho, Lourenço

    2015-10-01

    This study investigated the influence of water storage (24 h and 6 months), and Transbond XT and Fuji Ortho LC bonding materials on the bond strength of metallic brackets bonded to feldspathic ceramic. Four cylinders of feldspathic ceramic were etched with 10% hydrofluoric acid for 60 s. Each cylinder received two layers of silane. Metallic brackets were bonded to the cylinders using Transbond XT or Fuji Ortho LC. Light-activation was carried out with 40 s total exposure time using Bluephase G2. Half the specimens for each bonding materials (n=20) were stored in distilled water at 37 °C for 24 h and the other half for 6 months. Shear bond strength testing was performed after storage times at a crosshead speed of 1 mm/min. The adhesive remnant index (ARI) was used to evaluate the amount of adhesive remaining on the ceramic surface at ×8 magnification. Data were subjected to two-way ANOVA and Tukey's test (p<0.05). Transbond XT showed significantly higher bond strength (p<0.05) than Fuji Ortho LC. Significant differences in bond strength (p<0.05) were found when 24 h and 6 months storage times were compared between materials. ARI showed a predominance of score 0 for all groups, and higher scores at 1, 2 and 3 for 24 h storage time. In conclusion, storage time and bonding materials showed significant influence on the bond strength of brackets to ceramic. PMID:26647936

  14. Structural and dielectric properties of Mg-doped strontium titanate ceramics: dependence on the materials processing

    Czech Academy of Sciences Publication Activity Database

    Tkach, A.; Vilarinho, P.; Kholkin, A.; Reaney, I. M.; Petzelt, Jan

    455-456, - (2004), s. 40-44. ISSN 0255-5476 Institutional research plan: CEZ:AV0Z1010914 Keywords : SrTiO 3 * doping * materials processing * dielectric ceramics * structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.498, year: 2004

  15. 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

  16. The use of luminescence techniques with ceramic materials for retrospective dosimetry

    International Nuclear Information System (INIS)

    Luminescence techniques are being used with ceramic materials to provide evaluations of integrated external gamma dose for dose reconstruction in populated areas contaminated by Chernobyl fallout. A range of suitable ceramics can be found associated with buildings: on the exterior surfaces (tiles), within walls (bricks) and within the interiors (porcelain fittings and tiles). Dose evaluations obtained using such samples provide information concerning the time-averaged incident gamma radiation field, average shielding factors and, with the aid of computational modelling techniques, dose estimates at external reference positions

  17. 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.

  18. The Influence of Tool Composite's Structure During Process of Diamond Grinding of Ceramic Materials

    Directory of Open Access Journals (Sweden)

    Gawlik Józef

    2014-12-01

    Full Text Available This paper presents the results of the tests performed during the grinding process of the ceramic materials: – polycrystalline ceramics (Zirconium ZrO2 and mono-crystalline ceramics (sapphire α-Al2O3 by the diamond tools. Studies have shown that the concentration (thickening of the tool composite changes the tool's pore structure when using suitable wetted adamantine additives. Such modified composite has positive impact on tribological properties of the subsurface layer of the machined components. This is manifested by the reduction of the surface roughness and reduction of the vibration amplitude of the coefficient of friction. The possibilities of the positive effects when using wetted additives on the tool's composite during the pressing (briquetting stage confirm the study results.

  19. Glass and glass–ceramic coatings, versatile materials for industrial and engineering applications

    Indian Academy of Sciences (India)

    Amitava Majumdar; Sunirmal Jana

    2001-02-01

    Among various coating systems for industrial and engineering applications, glass and glass–ceramic coatings have advantages of chemical inertness, high temperature stability and superior mechanical properties such as abrasion, impact etc as compared to other coating materials applied by thermal spraying in its different forms viz. PVD, CVD, plasma, etc. Besides imparting required functional properties such as heat, abrasion and corrosion resistance to suit particular end use requirements, the glass and glass–ceramic coatings in general also provide good adherence, defect free surface and refractoriness. Systematic studies covering the basic science of glass and glass–ceramic coatings, the functional properties required for a particular end-use along with the various fields of application have been reviewed in this paper.

  20. Laser ceramic materials for subpicosecond solid-state lasers using Nd3+-doped mixed scandium garnets.

    Science.gov (United States)

    Okada, Hajime; Tanaka, Momoko; Kiriyama, Hiromitsu; Nakai, Yoshiki; Ochi, Yoshihiro; Sugiyama, Akira; Daido, Hiroyuki; Kimura, Toyoaki; Yanagitani, Takagimi; Yagi, Hideki; Meichin, Noriyuki

    2010-09-15

    We have successfully developed and demonstrated broadband emission Nd-doped mixed scandium garnets based on laser ceramic technology. The inhomogeneous broadening of Nd(3+) fluorescence lines results in a bandwidth above 5 nm that is significantly broader than that for Nd:YAG and enables subpicosecond mode-locked pulse durations. We have also found the emission cross section of 7.8 × 10(-20) cm(2) to be adequate for efficient energy extraction and thermal conductivity of 4.7 W/mK from these new Nd-doped laser ceramics. The new laser ceramics are good candidates for laser host material in a diode-pumped subpicosecond laser system with high efficiency and high repetition rate. PMID:20847774

  1. 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.

  2. 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

    protons, oxygen ions and/or electronic carriers, stability, etc. The present chapter will therefore consider the structural features of selected material classes, as well as the principles of transport in bulk and microporous solids. It will furthermore illustrate and discuss the effects of selected...... separation and ion/electron transport at the relevant operating conditions and stability ranges, improved electrical or ionic conductivities and permeation rates are required. That can be achieved by doping and substitution which are actors on a nano-scale that usually lead to macroscopic impacts. This...... 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...

  3. Status and perspective of the R and D on ceramic breeder materials for testing in ITER

    International Nuclear Information System (INIS)

    The main line of ceramic breeder materials research and development is based on the use of the breeder material in the form of pebble beds. At present, there are three candidate pebble materials (Li4SiO4, and two forms of Li2TiO3) for DEMO reactors that will be used for testing in ITER. This paper reviews the R and D of as-fabricated pebble materials against the blanket performance requirements and makes recommendations on necessary steps toward the qualification of these materials for testing in ITER

  4. Development and application of ferrite materials for low temperature co-fired ceramic technology

    International Nuclear Information System (INIS)

    Development and application of ferrite materials for low temperature co-fired ceramic (LTCC) technology are discussed, specifically addressing several typical ferrite materials such as M-type barium ferrite, NiCuZn ferrite, YIG ferrite, and lithium ferrite. In order to permit co-firing with a silver internal electrode in LTCC process, the sintering temperature of ferrite materials should be less than 950 °C. These ferrite materials are research focuses and are applied in many ways in electronics. (review - magnetism, magnetic materials, and interdisciplinary research)

  5. A review of candidate ceramic materials for use as heat shield tiles in a supercritical-water-cooled-reactor

    International Nuclear Information System (INIS)

    The proposed Canadian supercritical-water-cooled reactor (SCWR) utilizes a reactor shell made of a zirconium alloy insulated with a ceramic tile heat shield. The main consideration in the selection of a tile material will be resistance to corrosion in supercritical water and long term microstructure stability, in addition to thermal conductivity. This paper provides a review of the literature on corrosion behaviours of ceramic materials in supercritical water and ranks candidate ceramic materials accordingly. Materials reviewed include alumina, zirconia, silica glasses, silicon carbide, silicon nitride, sialon, mullite, and aluminum nitride. (author)

  6. Chemical, mineralogical and ceramic properties of kaolinitic materials from the Tresnuraghes mining district (Western Sardinia, Italy)

    OpenAIRE

    Dondi, Michele; Guarini, Guia; Ligas, Paola; Raimondo, Mariarosa; Palomba, Marcella; Uras, Ivo

    2001-01-01

    Kaolinitic materials crop out in the Tresnuraghes mining district (Western Sardinia, Italy). Three main kaolinitic deposits, located in the Patalza, Salamura and Su Fongarazzu areas, respectively, were investigated in order to assess their potential in the ceramic industry. The parent rock-types of this raw material are the Oligocene-Miocene rhyolitic-rhyodacitic ignimbrites. Chemical and mineralogical analyses were performed on representative samples of each deposit, by XRD and XRF methodolo...

  7. Mechanical behavior of polycrystalline ceramics: Brittle fracture of SiC-Si3N4 materials

    Science.gov (United States)

    Leipold, M. H.; Kapadia, C. M.; Kelkar, A. H.

    1974-01-01

    The first study area involved magnesium oxide and the role of anion impurities, while the second area was directed toward slow crack growth in silicon nitride-silicon carbide ceramics. The oxide program involved development of fabrication techniques for anion doped materials and evaluation of the role of these anions in the hot pressing response, grain boundary diffusion of nickel doped material, grain boundary microhardness, and grain growth.

  8. The binding of lubricating films to ceramic and refractory materials

    International Nuclear Information System (INIS)

    In order to better understand the chemical bonding forces which control lubricating film stability and adhesion, the binding of lead and tin atoms on the ceramics alumina and silica was investigated by laser induced thermal evaporation combined with mass spectrometric detection of the evaporated species. The interaction between lead or tin and alumina and silica was studied as a function of coverage. The sticking probability for the interaction was measured and found to be temperature and coverage dependent. At low coverage the binding energy of lead to alumina and silica was determined as 237 and 246 kJ mol -1 respectively, while the binding energy of tin to alumina and silica is 313 and 331 kJ mol -1, respectively. A binding energy model based on thermochemical and crystallographic data is used to predict corresponding values which agree with the experimental values. In addition, the authors report temperature programmed desorption and/or decomposition (This patent describes) used to investigate the thermal and/or chemical stability of MoS2 films on molybdenum supports. The TPD spectra for S2 from Mos2 were analyzed, and activation energies found to be dependent on the film application technique

  9. Control and characterization of ceramics materials by photothermic radiometry

    International Nuclear Information System (INIS)

    This work studies, by photothermal radiometry, semi-transparent and scattering ceramic coatings with a model in an axisymetrical geometry. The equation of the radiative transfer is solved thanks to a ten flux-model in order to calculate the luminance field, the radiative flux and the source term with a method by finite differences or the Fourier transform. The term of the source is introduced into the heat equation to calculate the temperature field. Theoretical simulations show the influence of the experimental conditions and the characteristics of the sample. The optical properties, which are necessary for the preceding model, are determined by adjusting measures of hemispherical directional reflectivity and transmissivity. The samples are then analyzed by photothermal radiometry under random noise excitation, which allows us to determine their harmonic response (amplitude and phase) in a large range of modulation frequencies. The confrontation between theory and experimental presents a good agreement. The process allows us to characterize the properties of the coating, and to determine the thermal resistance equivalent to a flaw at the interface. (author). 105 refs., 112 figs., 11 annexes

  10. Development of a ceramic material to cover walls to be applied in diagnostic radiological protection

    International Nuclear Information System (INIS)

    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 SiO2, Fe2O3, Al2O3, CaO and Ti2O3. 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 BaSO4 (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 radiation attenuation were evaluated for all produced

  11. 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.

  12. Structural ceramic coatings in composite microtruss cellular materials

    International Nuclear Information System (INIS)

    Graphical abstract: The compressive strength increase per unit sleeve thickness of Al cores reinforced with Al2O3 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 Al2O3 coating was able to achieve this performance increase with little overall weight penalty (right). Display Omitted Highlights: → A new type of metal/ceramic microtruss cellular composite has been created. → Reinforcing sleeves of Al2O3 were deposited on low density Al microtruss cores. → Significant compressive strength increases were seen at virtually no weight penalty. → Failure mechanisms were studied by electron microscopy and finite element analysis. → Buckling, sleeve wrinkling, and coating fracture dictated the compressive strength. - Abstract: In the present study, anodizing was used to produce Al2O3 coatings in a conventional 3003 aluminum alloy microtruss core; a 38.5 μm 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.

  13. 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.

  14. Radiometric analysis of raw materials and end products in the Turkish ceramics industry

    International Nuclear Information System (INIS)

    This study presents the findings of radiometric analysis carried out to determine the activity concentrations of natural radionuclides in raw materials (clay, kaolin, quartz, feldspar, dolomite, alumina, bauxite, zirconium minerals, red mud and frit) and end products (glazed ceramic wall and floor tiles) in the Turkish ceramics industry. Hundred forty-six samples were obtained from various manufacturers and suppliers throughout the country and analyzed using gamma-ray spectrometer with HPGe detectors. Radiological parameters such as radium equivalent activity, activity concentration index and alpha index were calculated to assess the radiological aspects of the use of the ceramic end products as decorative or covering materials in construction sector. Results obtained were examined in the light of the relevant national and international legislation and guidance and compared with the results of similar studies reported in different countries. The results suggest that the use of ceramic end product samples examined in the construction of dwellings, workplaces and industrial buildings in Turkey is unlikely to give rise to any significant radiation exposure to the occupants.

  15. Thermodynamic analysis of chemical stability of ceramic materials in hydrogen-containing atmospheres at high temperatures

    Science.gov (United States)

    Misra, Ajay K.

    1990-01-01

    The chemical stability of several ceramic materials in hydrogen-containing environments was analyzed with thermodynamic considerations in mind. Equilibrium calculations were made as a function of temperature, moisture content, and total system pressure. The following ceramic materials were considered in this study: SiC, Si3N4, SiO2, Al2O3, mullite, ZrO2, Y2O3, CaO, MgO, BeO, TiB2, TiC, HfC, and ZrC. On the basis of purely thermodynamic arguments, upper temperature limits are suggested for each material for long-term use in H2-containing atmospheres.

  16. Influence of the supporting die structures on the fracture strength of all-ceramic materials.

    Science.gov (United States)

    Yucel, Munir Tolga; Yondem, Isa; Aykent, Filiz; Eraslan, Oğuz

    2012-08-01

    This study investigated the influence of the elastic modulus of supporting dies on the fracture strengths of all-ceramic materials used in dental crowns. Four different types of supporting die materials (dentin, epoxy resin, brass, and stainless steel) (24 per group) were prepared using a milling machine to simulate a mandibular molar all-ceramic core preparation. A total number of 96 zirconia cores were fabricated using a CAD/CAM system. The specimens were divided into two groups. In the first group, cores were cemented to substructures using a dual-cure resin cement. In the second group, cores were not cemented to the supporting dies. The specimens were loaded using a universal testing machine at a crosshead speed of 0.5 mm/min until fracture occurred. Data were statistically analyzed using two-way analysis of variance and Tukey HSD tests (α = 0.05). The geometric models of cores and supporting die materials were developed using finite element method to obtain the stress distribution of the forces. Cemented groups showed statistically higher fracture strength values than non-cemented groups. While ceramic cores on stainless steel dies showed the highest fracture strength values, ceramic cores on dentin dies showed the lowest fracture strength values among the groups. The elastic modulus of the supporting die structure is a significant factor in determining the fracture resistance of all-ceramic crowns. Using supporting die structures that have a low elastic modulus may be suitable for fracture strength tests, in order to accurately reflect clinical conditions. PMID:21845404

  17. 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.

  18. Radioactive waste immobilization using ion-exchange materials which form glass-ceramics

    International Nuclear Information System (INIS)

    This invention provides a process for the production of a glass-ceramic composite product in which the crystalline phase is thermodynamically stable and compatible with the host rock. The process comprises: (a) passing liquid radioactive waste materials through an inorganic ion exchange medium; (b) heating the ion exchange materials with sufficient glass-forming materials to form a melt; (c) cooling the melt to form a glass; and (d) heat treating the glass to crystallize sphene crystallites in a protective glassy matrix that contains the radioactive materials. There is also provided a cartridge containing the ion exchange medium

  19. Bonding values of two contemporary ceramic inlay materials to dentin following simulated aging

    Science.gov (United States)

    Khalil, Ashraf Abdelfattah

    2015-01-01

    PURPOSE To compare the push-out bond strength of feldspar and zirconia-based ceramic inlays bonded to dentin with different resin cements following simulated aging. MATERIALS AND METHODS Occlusal cavities in 80 extracted molars were restored in 2 groups (n=40) with CAD/CAM feldspar (Vitablocs Trilux forte) (FP) and zirconia-based (Ceramill Zi) (ZR) ceramic inlays. The fabricated inlays were luted in 2 subgroups (n=20) with either etch-and-bond (RelyX Ultimate Clicker) (EB) or self-adhesive (RelyX Unicem Aplicap) (SA) resin cement. Ten inlays in each subgroup were subjected to 3,500 thermal cycles and 24,000 loading cycles, while the other 10 served as control. Horizontal 3 mm thick specimens were cut out of the restored teeth for push out bond strength testing. Bond strength data were statistically analyzed using 1-way ANOVA and Tukey's comparisons at α=.05. The mode of ceramic-cement-dentin bond failure for each specimen was also assessed. RESULTS No statistically significant differences were noticed between FP and ZR bond strength to dentin in all subgroups (ANOVA, P=.05113). No differences were noticed between EB and SA (Tukey's, P>.05) bonded to either type of ceramics. Both adhesive and mixed modes of bond failure were dominant for non-aged inlays. Simulated aging had no significant effect on bond strength values (Tukey's, P>.05) of all ceramic-cement combinations although the adhesive mode of bond failure became more common (60-80%) in aged inlays. CONCLUSION The suggested cement-ceramic combinations offer comparable bonding performance to dentin substrate either before or after simulated aging that seems to have no adverse effect on the achieved bond. PMID:26816574

  20. Multimillion atom molecular dynamics simulations of glasses and ceramic materials

    International Nuclear Information System (INIS)

    Molecular dynamics simulations are a powerful tool for studying physical and chemical phenomena in materials. In these lectures we shall review the molecular dynamics method and its implementation on parallel computer architectures. Using the molecular dynamics method we will study a number of materials in different ranges of density, temperature, and uniaxial strain. These include structural correlations in silica glass under pressure, crack propagation in silicon nitride films, sintering of silicon nitride nanoclusters, consolidation of nanophase materials, and dynamic fracture. Multimillion atom simulations of oxidation of aluminum nanoclusters and nanoindentation in silicon nitride will also be discussed. (c) 1999 American Institute of Physics

  1. Tempered glass and thermal shock of ceramic materials

    Science.gov (United States)

    Bunnell, L. Roy

    1992-01-01

    A laboratory experiment is described that shows students the different strengths and fracture toughnesses between tempered and untempered glass. This paper also describes how glass is tempered and the materials science aspects of the process.

  2. An investigation of neutron irradiation test on superplastic zirconia-ceramic materials

    International Nuclear Information System (INIS)

    A neutron irradiation test on superplastic ceramic materials at high temperature has been proposed as an innovative basic research on high-temperature engineering using the High Temperature Engineering Test Reactor (HTTR). For the effective execution of the test, we reviewed the superplastic deformation mechanism of ceramic materials and discussed neutron irradiation effects on the superplastic deformation process of stabilized Tetragonal Zirconia Polycrystal (TZP), which is a representative superplastic ceramic material. As a result, we pointed out that the decrease in the activation energy for superplastic deformation is expected by the radiation-enhanced diffusion. We selected a fast neutron fluence of 5x1020 n/cm2 and an irradiation temperature of about 600degC as test conditions for the first irradiation test on TZP and decided to perform a preliminary irradiation test by the Japan Materials Testing Reactor (JMTR). Moreover, we estimated the radioactivity of irradiated TZP and indicated that it is in the order of 1010 Bq/g (about 0.3 Ci/g) immediately after irradiation to a thermal neutron fluence of 3x1020 n/cm2 and that it decays to about 1/100 in a year. (author)

  3. An investigation of neutron irradiation test on superplastic zirconia-ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Taiju; Ishihara, Masahiro; Baba, Shinichi; Hayashi, Kimio [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Motohashi, Yoshinobu [Ibaraki Univ., Mito (Japan)

    2000-05-01

    A neutron irradiation test on superplastic ceramic materials at high temperature has been proposed as an innovative basic research on high-temperature engineering using the High Temperature Engineering Test Reactor (HTTR). For the effective execution of the test, we reviewed the superplastic deformation mechanism of ceramic materials and discussed neutron irradiation effects on the superplastic deformation process of stabilized Tetragonal Zirconia Polycrystal (TZP), which is a representative superplastic ceramic material. As a result, we pointed out that the decrease in the activation energy for superplastic deformation is expected by the radiation-enhanced diffusion. We selected a fast neutron fluence of 5x10{sup 20} n/cm{sup 2} and an irradiation temperature of about 600degC as test conditions for the first irradiation test on TZP and decided to perform a preliminary irradiation test by the Japan Materials Testing Reactor (JMTR). Moreover, we estimated the radioactivity of irradiated TZP and indicated that it is in the order of 10{sup 10} Bq/g (about 0.3 Ci/g) immediately after irradiation to a thermal neutron fluence of 3x10{sup 20} n/cm{sup 2} and that it decays to about 1/100 in a year. (author)

  4. Agricultural wastes as a resource of raw materials for developing low-dielectric glass-ceramics

    Science.gov (United States)

    Danewalia, Satwinder Singh; Sharma, Gaurav; Thakur, Samita; Singh, K.

    2016-04-01

    Agricultural waste ashes are used as resource materials to synthesize new glass and glass-ceramics. The as-prepared materials are characterized using various techniques for their structural and dielectric properties to check their suitability in microelectronic applications. Sugarcane leaves ash exhibits higher content of alkali metal oxides than rice husk ash, which reduces the melting point of the components due to eutectic reactions. The addition of sugarcane leaves ash in rice husk ash promotes the glass formation. Additionally, it prevents the cristobalite phase formation. These materials are inherently porous, which is responsible for low dielectric permittivity i.e. 9 to 40. The presence of less ordered augite phase enhances the dielectric permittivity as compared to cristobalite and tridymite phases. The present glass-ceramics exhibit lower losses than similar materials synthesized using conventional minerals. The dielectric permittivity is independent to a wide range of temperature and frequency. The glass-ceramics developed with adequately devitrified phases can be used in microelectronic devices and other dielectric applications.

  5. Thermo-mechano-chemical stability of ceramic materials during the electrowinning process using liquid metal electrodes in molten salts

    International Nuclear Information System (INIS)

    Pyroprocessing, which results in proliferation resistance, shows promise as an alternative to wet processing in the recycling of transuranics. However, the ceramic crucible used in the electrowinning process poses an issue during pyroprocessing. The crucible is chemically unstable and prone to thermal fatigue. In this study, the thermodynamic simulation software HSC (enthalpy, entropy and heat capacity) Chemistry was employed to evaluate the chemical stabilities of different ceramic crucibles containing liquid cadmium as well as liquid bismuth cathodes, which also contained rare earth elements and lithium. The chemical stabilities were experimentally validated by measuring the contact angles between the liquid cathode (LC) materials and four ceramic materials (Al2O3, MgO, Y2O3, and BeO) in situ. The infiltration depths of the liquid bismuth cathode elements were measured using X-ray photoelectron spectroscopy. To determine the Weibull distributions of the investigated ceramics, thermal fatigue tests were performed using plates of the ceramics. (author)

  6. 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.

  7. Tensile behavior of glass/ceramic composite materials at elevated temperatures

    Science.gov (United States)

    Mandell, J. F.; Grande, D. H.; Jacobs, J.

    1987-01-01

    This paper describes the tensile behavior of high-temperature composite materials containing continuous Nicalon ceramic fiber reinforcement and glass and glass/ceramic matrices. The longitudinal properties of these materials can approach theoretical expectations for brittle matrix composites, failing at a strength and ultimate strain level consistent with those of the fibers. The brittle, high-modulus matrices result in a nonlinear stress-strain curve due to the onset of stable matrix cracking at 10 to 30 percent of the fiber strain to failure, and at strains below this range in off-axis plies. Current fibers and matrices can provide attractive properties well above 1000 C, but composites experience embrittlement in oxidizing atmospheres at 800 to 1000 C due to oxidation of a carbon interface reaction layer.The oxidation effect greatly increases the interface bond strength, causing composite embrittlement.

  8. Dimensional stability. [of glass and glass-ceramic materials in diffraction telescopes

    Science.gov (United States)

    Hochen, R.; Justie, B.

    1976-01-01

    The temporal stability of glass and glass-ceramic materials is important to the success of a large diffraction-limited telescope. The results are presented of an experimental study of the dimensional stability of glasses and glass ceramics being considered for substrates of massive diffraction-limited mirrors designed for several years of service in earth orbit. The purpose of the study was to measure the relative change in length of the candidate substrate materials, to the order of 5 parts in 10 to the 8th power, as a function of several years time. The development of monolithic test etalons, the development and improvement of two types of ultra-high precision interferometers, and certain aspects of tests data presently achieved are discussed.

  9. EXOTIC-7: irradiation of ceramic breeder materials to high lithium burnup

    International Nuclear Information System (INIS)

    The EXOTIC-7 irradiation experiment in the high flux reactor (HFR) has been completed. Its aim has been to investigate the effects of high lithium-burnup on the mechanical stability and tritium release characteristics of candidate ceramic breeder materials, originating from the fusion programmes of CEA, FZK, ENEA, AECL and ECN. The tested ceramic breeder materials were pellets of Li2ZrO3, LiAlO2 and Li8ZrO6 and pebbles of Li4SiO4 and Li2ZrO3, with a variety of characteristics, like grain size and porosity. The test matrix provided the simultaneous irradiation of eight independent capsules with on-line tritium monitoring. Two capsules contained a mixture of Li4SiO4 and beryllium pebbles. The experimental design, sample loading and main irradiation parameters are described. Some PIE results and analysis of in-situ tritium release behaviour are presented. (orig.)

  10. Environmental and economic aspects of using marble fine waste in the manufacture of facing ceramic materials

    Directory of Open Access Journals (Sweden)

    Zemlyanushnov Dmitriy Yur'evich

    2014-09-01

    Full Text Available This work considers economic expediency of using marble fine waste in facing ceramic materials manufacture by three-dimensional coloring method. Adding marble fine waste to the charge mixture reduces the production cost of the final product. This waste has a positive impact on the intensification of drying clay rocks and raw as a whole, which increases production efficiency. Using marble fine waste as a coloring admixture makes it possible to manufacture more environmentally friendly construction material with the use of wastes of hazard class 3 instead of class 4. At the same time, disposal areas and environmental load in the territories of mining and marble processing reduce significantly. Replacing ferrous pigments with manganese oxide for marble fine waste reduces the cost of the final product and the manufacture of facing ceramic brick of a wide range of colors - from dark brown to yellow.

  11. The Effect of Plasma Surface Treatment on a Porous Green Ceramic Film with Polymeric Binder Materials

    Science.gov (United States)

    Jeong, Woo Yun

    2013-06-01

    To reduce time and energy during thermal binder removal in the ceramic process, plasma surface treatment was applied before the lamination process. The adhesion strength in the lamination films was enhanced by oxidative plasma treatment of the porous green ceramic film with polymeric binding materials. The oxygen plasma characteristics were investigated through experimental parameters and weight loss analysis. The experimental results revealed the need for parameter analysis, including gas material, process time, flow rate, and discharge power, and supported a mechanism consisting of competing ablation and deposition processes. The weight loss analysis was conducted for cyclic plasma treatment rather than continuous plasma treatment for the purpose of improving the film's permeability by suppressing deposition of the ablated species. The cyclic plasma treatment improved the permeability compared to the continuous plasma treatment.

  12. The Effect of Plasma Surface Treatment on a Porous Green Ceramic Film with Polymeric Binder Materials

    International Nuclear Information System (INIS)

    To reduce time and energy during thermal binder removal in the ceramic process, plasma surface treatment was applied before the lamination process. The adhesion strength in the lamination films was enhanced by oxidative plasma treatment of the porous green ceramic film with polymeric binding materials. The oxygen plasma characteristics were investigated through experimental parameters and weight loss analysis. The experimental results revealed the need for parameter analysis, including gas material, process time, flow rate, and discharge power, and supported a mechanism consisting of competing ablation and deposition processes. The weight loss analysis was conducted for cyclic plasma treatment rather than continuous plasma treatment for the purpose of improving the film's permeability by suppressing deposition of the ablated species. The cyclic plasma treatment improved the permeability compared to the continuous plasma treatment.

  13. A method for developing design diagrams for ceramic and glass materials using fatigue data

    Science.gov (United States)

    Heslin, T. M.; Magida, M. B.; Forrest, K. A.

    1986-01-01

    The service lifetime of glass and ceramic materials can be expressed as a plot of time-to-failure versus applied stress whose plot is parametric in percent probability of failure. This type of plot is called a design diagram. Confidence interval estimates for such plots depend on the type of test that is used to generate the data, on assumptions made concerning the statistical distribution of the test results, and on the type of analysis used. This report outlines the development of design diagrams for glass and ceramic materials in engineering terms using static or dynamic fatigue tests, assuming either no particular statistical distribution of test results or a Weibull distribution and using either median value or homologous ratio analysis of the test results.

  14. 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.

  15. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Science.gov (United States)

    Wananuruksawong, R.; Jinawath, S.; Padipatvuthikul, P.; Wasanapiarnpong, T.

    2011-10-01

    Silicon nitride (Si3N4) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si3N4 ceramic as a dental core material. The white Si3N4 was prepared by pressureless sintering at relative low sintering temperature of 1650 °C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si3N4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si3N4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (<150 micrometer, Pyrex) with 5 wt% of zirconia powder (3 wt% Y2O3 - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si3N4 specimens, the firing was performed in electric tube furnace between 1000-1200°C. The veneered specimens fired at 1100°C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98×10-6 °C-1, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  16. Vibronic Jahn-Teller coupling and structural-systematic aspects of superconductivity in ceramic materials

    International Nuclear Information System (INIS)

    The following subjects were mainly investigated: 1. Development of a concept concerning the mechanism of superconductivity in ceramic oxides from the standpoint of solid state chemistry. An important criterion for generating superconductivity in ceramic oxides seems to be the overlap of a narrow, weakly antibonding and metal-centred band with a very broad band of predominant oxygen character in the Fermi region. Spectroscopic investigations are in favour of such a concept and additionally indicate a vibronic coupling mechanism of the Jahn-Teller- or pseudo-Jahn-Teller type. 2. Synthesis of potentially superconducting ceramic oxides. A series of oxidic compounds with transition metal ions (Ni2+/Ni3+/Ni4+, Mn3+/Mn4+, Cu2+/Cu3+ etc.) and with cations, possessing a lone electron pair (Sb3+, Bi3+, Pb2+, Tl+) was prepared (K2NiF4-structure). The investigation of these ceramic materials led to interesting insight into the nature of the M-O-bond and the cooperative interactions between the metal ion centres; new superconductors could not be synthesized, however. (orig.)

  17. Calculation of the Ceramic Material Parameters from the Destructions

    Czech Academy of Sciences Publication Activity Database

    Fuis, Vladimír; Houfek, Martin

    Rio de Janeiro : SBPMat, 2009. s. 1-1. ISSN 1983-7542. [ICAM 2009. 20.09.2009-25.09.2009, Rio de Janeiro] Institutional research plan: CEZ:AV0Z20760514 Keywords : weibull * material parameters * destruction tests Subject RIV: BO - Biophysics http://www.icam2009.com/

  18. Metals and Ceramics Division materials science program. Annual progress report for period ending June 30, 1981

    International Nuclear Information System (INIS)

    Information is presented concerning the theoretical studies of metals and alloys; x-ray diffraction research; structural ceramics; structure of coal; analytical and high-voltage electron microscopy; deformation and mechanical properties; mechanisms of surface and solid-state reactions; physical properties research; metastable materials; neutron radiation effects; charged particle radiation effects; theory and modeling of radiation effects; facility and advanced technique development; fundamentals of welding and joining; and studies in nondestructive evaluation

  19. Tensile Strength Measurements of Ceramic Materials at High Rates of Strain

    OpenAIRE

    Gálvez, F.; Rodríguez, J.; V. Sánchez

    1997-01-01

    Ceramic materials are usually assumed linear elastic up to failure and the failure criterion is accustomed to be a limit condition related to the tensile strength. Due to the difficulties associated with the uniaxial tensile test, some different alternatives have been posed such as Brazilian tests and spalling test of long bars. In this work, a comparative study of these methods has been broached. Specimens of alumina and silicon carbide have been tested at different strain rates, showing the...

  20. Environmental and economic aspects of using marble fine waste in the manufacture of facing ceramic materials

    OpenAIRE

    Zemlyanushnov Dmitriy Yur'evich; Sokov Viktor Nikolaevich; Oreshkin Dmitriy Vladimirovich

    2014-01-01

    This work considers economic expediency of using marble fine waste in facing ceramic materials manufacture by three-dimensional coloring method. Adding marble fine waste to the charge mixture reduces the production cost of the final product. This waste has a positive impact on the intensification of drying clay rocks and raw as a whole, which increases production efficiency. Using marble fine waste as a coloring admixture makes it possible to manufacture more environmentally friendly construc...

  1. Calculation of weibull material parameters of the ceramic head

    Czech Academy of Sciences Publication Activity Database

    Fuis, Vladimír; Hlavoň, Pavel; Návrat, Tomáš

    Gliwice : Wydawnictwo Katerdry Mechaniki Stosowanej, 2006 - (Gutkowski, W.), s. 15-18 ISBN 83-60102-30-9. [Modelling and optimization of physical systems. Wisla (PL), 16.06.2006-18.06.2006] R&D Projects: GA ČR(CZ) GP101/04/P037 Institutional research plan: CEZ:AV0Z20760514 Keywords : Weibul material parameters * FEM * bioceramics Subject RIV: BO - Biophysics

  2. Effect of glycine pretreatment on the shear bond strength of a CAD/CAM resin nano ceramic material to dentin

    OpenAIRE

    Ceci, Matteo; Pigozzo, Marco; Scribante, Andrea; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco; Poggio, Claudio

    2016-01-01

    Background The purpose of this study was to evaluate the effect of glycine pretreatment on the shear bond strength between dentin and a CAD/CAM resin nano ceramic material (LavaTM Ultimate Restorative), bonded together with adhesive cements using three different luting protocols (total-etch; self-etch; self-adhesive). Material and Methods Thirty cylinders were milled from resin nano ceramic blocks with CAD/CAM technology. The cylinders were subsequently cemented to the exposed dentin of 30 bo...

  3. Effect of glycine pretreatment on the shear bond strength of a CAD/CAM resin nano ceramic material to dentin

    OpenAIRE

    Ceci, Matteo; Pigozzo, Marco; Scribante, Andrea; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco; Poggio, Claudio

    2016-01-01

    Background: The purpose of this study was to evaluate the effect of glycine pretreatment on the shear bond strength between dentin and a CAD/CAM resin nano ceramic material (LavaTM Ultimate Restorative), bonded together with adhesive cements using three different luting protocols (total-etch; self-etch; self-adhesive). Material and Methods: Thirty cylinders were milled from resin nano ceramic blocks with CAD/CAM technology. The cylinders were subsequently cemented...

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

    Energy Technology Data Exchange (ETDEWEB)

    Crossland, C.E.; Shelleman, D.L.; Spear, K.E. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    1996-08-01

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

  5. Evaluation of ceramic and polymeric materials for use in engineered barrier systems

    International Nuclear Information System (INIS)

    Ceramic materials evaluated in the screening studies were Al2O3 (99.8%), mullite, vitreous silica, BaTiO3, CaTiO3, CaZrO3, CaTiSiO5, TiO2, ZrSiO4, basalt, Pyroceram 9617, and Marcor code 9658 machinable glass ceramic. One grade of graphite (Toyotanso IB-11) was also evaluated. Demineralized water, a synthetic Hanford groundwater, and a synthetic NaCl brine solution were used in the screening tests. Demineralized water was used in all five of the leach tests, but the other solutions were only used in the static leach tests at 150 and 2500C. Based on the results obtained, graphite appears to be the most leach resistant of the materials tested with the two grades of alumina being the best of the ceramic materials. Titanium dioxide and ZrO2 are the most leach resistant of the remaining materials. Candidate materials from all three general classes of polymers (thermoplastics, thermosets, and elastomers) were considered in the selection of materials. Selected groups of polymers were tested in the flowing autoclave at 150, 200, and 2500C with some polymers being further tested at the next higher temperature. Next, selected samples were exposed to gamma radiation. These samples were then submitted for tensile and elongation measurements. Selected samples which appeared promising from both autoclave and radiation testing were further evaluated by impact tests. The materials that appeared most promising after autoclave testing were the EPDM rubbers, polyphenylene sulfide, poly(ethylene-tetrafluoroethylene) copolymer, and polyfurfuryl alcohol. The radiation dose had little effect on polyfurfuryl alcohol and polyphenylene sulfide samples; very significant decreases in elongation were observed for the fluorocarbon copolymer and the EPDM rubbers. While the polyphenylene sulfide and polyfurfuryl alcohol showed little change in impact strength, poly(ethylene-tetrafluoroethylene) decreased in impact strength

  6. Theoretical analysis of material removal mechanisms in pulsed laser fusion cutting of ceramics

    International Nuclear Information System (INIS)

    It is well known that the efficiency of material removal mechanisms has a crucial influence on the performance and quality of the laser cutting process. However, they are very difficult to study since the physical processes and parameters which govern them are quite complicated to observe and measure experimentally. For this reason, the development of theoretical models to analyse the material removal mechanisms is very important for understanding the characteristics and influence of these processes. In this paper, a theoretical model of the pulsed laser fusion cutting of ceramics is presented. The material removal mechanisms from the cutting front are modelled under the assumption that the ceramic material may be, simultaneously, melted and evaporated by the laser radiation. Therefore, three ejection mechanisms are investigated together: ejection of molten material by the assist gas, evaporation of the liquid and ejection of molten material due to the recoil pressure generated by the evaporation from the cutting front. The temporal evolution of the material removal mechanisms and the thickness of the molten layer are solved for several laser pulse modes. Theoretical results are compared with experimental observations to validate the conclusions regarding the influence of frequency and pulse length on the cutting process

  7. Powder metallurgical fabrication of metal/ceramic functionally graded materials for high temperature use

    International Nuclear Information System (INIS)

    Powder metallurgical fabrication of metal/ceramic functionally graded material (FGM) has been described. The first part of this paper briefly shows the concept of FGM with the special reference to the large progress of research works on thermal barrier materials where the role of thermal stress relaxation function has been emphasized. Then, powder metallurgical processing of this type of FGM is reviewed on the basis of recent activities. Graded structures may be found in ordinary engineering materials from former days; however, if one has begun to tailor the intentional gradient of composition and/or microstructure in a material in order to achieve the desired functions and properties, the material shall possess the concept of Functionally Graded Material (FGM). The FGM has the great potential of applications in many fields by using gradient on chemical, biochemical, physical and mechanical properties. (author)

  8. 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.

  9. Thermodynamics of ceramic breeder materials for fusion reactors

    International Nuclear Information System (INIS)

    Based on known or deduced phase relationships in ternary lithium oxygen systems such as Li-Al-O, Li-Si-O and Li-Zr-O, the unknown free enthalpy of formation values of ternary compounds are calculated starting from the known data of the compounds of the binary border systems. Criterion for the data assessment is interconsistency of the data of all the compounds within a given multi-component system. With the help of these data the development of partial pressures during the breeding process can be calculated for all the compounds of interest. In order to facilitate a compatibility assessment the quaternary systems Cr-Li-Si-O, Fe-Li-Si-O and Be-Li-Si-O were also investigated and thermodynamic data of pertinent ternary and quaternary compounds determined. Both the partial pressure development and the compatibility behaviour of a lithium containing compound are criteria for its qualification as a breeder material for a fusion reactor. (orig.)

  10. 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.

  11. Fabrication of porous LiAlO2 ceramic breeder material

    International Nuclear Information System (INIS)

    The gamma-LiAlO2 ceramic material is the reference candidate for the solid breeder option of the Next European Torus Program. The experiments and methodologies developed in Italy to produce high surface area gamma-LiAlO2 powders to be compacted by cold pressing and sintering at 70 to 90% of the theoretical density, keeping a near fully open porosity is presented. The lithiating step was assessed for the Li2CO3 and Li2O2 precursors reacting with Al2O3 having submicron grain size. Sol-gel methodologies were also developed for the gamma-LiAlO2 preparation by which very high surface area ceramic grade powders were obtained

  12. Thermoluminescence dating (TL-Dating): an absolute method for archeological dating of ceramic base materials

    International Nuclear Information System (INIS)

    Thermoluminescence dating is one of the known techniques that have been established in many laboratories across the regions. This technique is capable to date the archeological ceramic base materials and provides an absolute measurement with an accuracy of 5%. The study involves the dating of ceramic clay from historical site at Sungai Mas, Kuala Muda, Kedah. Pieces of broken poetry of archeological sample excavated by the Museum Department and Antiquity (JM4) have been dated using the TLD techniques at MINT laboratory. A TLD dosemeter of LiF chips is used for the background and sample dose measurement. The preparation of sample and the calibration techniques for the estimation of palaedose or dose presented in the sample since distant past is established. Results indicate that the samples are in the era of civilization from 200BP to 1600BP. Error factors associated in the measurement procedures are also discussed

  13. Microstructural Characterization of Reaction-Formed Silicon Carbide Ceramics. Materials Characterization

    Science.gov (United States)

    Singh, M.; Leonhardt, T. A.

    1995-01-01

    Microstructural characterization of two reaction-formed silicon carbide ceramics has been carried out by interference layering, plasma etching, and microscopy. These specimens contained free silicon and niobium disilicide as minor phases with silicon carbide as the major phase. In conventionally prepared samples, the niobium disilicide cannot be distinguished from silicon in optical micrographs. After interference layering, all phases are clearly distinguishable. Back scattered electron (BSE) imaging and energy dispersive spectrometry (EDS) confirmed the results obtained by interference layering. Plasma etching with CF4 plus 4% O2 selectively attacks silicon in these specimens. It is demonstrated that interference layering and plasma etching are very useful techniques in the phase identification and microstructural characterization of multiphase ceramic materials.

  14. Prediction of lifetime for ceramic materials in the elastic and viscoelastic region by fracture mechanical methods

    International Nuclear Information System (INIS)

    The investigation is mainly concerned with the effect of subcritical crack growth of ceramic materials on lifetime in static bending test and lifetime predictions. In the theoretical part the formulas of lifetime and dynamic bending strength are discussed in detail. In case of creep behaviour a procedure is proposed to make predictions possible. The experiments on Al2O3 and HPSN give a good agreement between predicted and measured lifetimes for linear elastic material behaviour. If creep behaviour dominates, the region of expected lifetimes and the qualitative shape of lifetime distribution can be predicted too. (orig.)

  15. ADVANCED CERAMIC MATERIALS FOR NEXT-GENERATION NUCLEAR APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Marra, J.

    2010-09-29

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

  16. Life Prediction/Reliability Data of Glass-Ceramic Material Determined for Radome Applications

    Science.gov (United States)

    Choi, Sung R.; Gyekenyesi, John P.

    2002-01-01

    Brittle materials, ceramics, are candidate materials for a variety of structural applications for a wide range of temperatures. However, the process of slow crack growth, occurring in any loading configuration, limits the service life of structural components. Therefore, it is important to accurately determine the slow crack growth parameters required for component life prediction using an appropriate test methodology. This test methodology also should be useful in determining the influence of component processing and composition variables on the slow crack growth behavior of newly developed or existing materials, thereby allowing the component processing and composition to be tailored and optimized to specific needs. Through the American Society for Testing and Materials (ASTM), the authors recently developed two test methods to determine the life prediction parameters of ceramics. The two test standards, ASTM 1368 for room temperature and ASTM C 1465 for elevated temperatures, were published in the 2001 Annual Book of ASTM Standards, Vol. 15.01. Briefly, the test method employs constant stress-rate (or dynamic fatigue) testing to determine flexural strengths as a function of the applied stress rate. The merit of this test method lies in its simplicity: strengths are measured in a routine manner in flexure at four or more applied stress rates with an appropriate number of test specimens at each applied stress rate. The slow crack growth parameters necessary for life prediction are then determined from a simple relationship between the strength and the applied stress rate. Extensive life prediction testing was conducted at the NASA Glenn Research Center using the developed ASTM C 1368 test method to determine the life prediction parameters of a glass-ceramic material that the Navy will use for radome applications.

  17. Lightweight Ablative and Ceramic Thermal Protection System Materials for NASA Exploration Systems Vehicles

    Science.gov (United States)

    Valentine, Peter G.; Lawrence, Timothy W.; Gubert, Michael K.; Milos, Frank S.; Kiser, James D.; Ohlhorst, Craig W.; Koenig, John R.

    2006-01-01

    As a collaborative effort among NASA Centers, the "Lightweight Nonmetallic Thermal Protection Materials Technology" Project was set up to assist mission/vehicle design trade studies, to support risk reduction in thermal protection system (TPS) material selections, to facilitate vehicle mass optimization, and to aid development of human-rated TPS qualification and certification plans. Missions performing aerocapture, aerobraking, or direct aeroentry rely on advanced heatshields that allow reductions in spacecraft mass by minimizing propellant requirements. Information will be presented on candidate materials for such reentry approaches and on screening tests conducted (material property and space environmental effects tests) to evaluate viable candidates. Seventeen materials, in three classes (ablatives, tiles, and ceramic matrix composites), were studied. In additional to physical, mechanical, and thermal property tests, high heat flux laser tests and simulated-reentry oxidation tests were performed. Space environmental effects testing, which included exposures to electrons, atomic oxygen, and hypervelocity impacts, was also conducted.

  18. Surface properties of ceramic/metal composite materials for thermionic converter applications

    International Nuclear Information System (INIS)

    Ceramic/metal composite electrode materials are of interest for thermionic energy conversion (TEC) applications for several reasons. These materials consist of submicron metal fibers or islands in an oxide matrix and therefore provide a basis for fabricating finely structured electrodes, with projecting or recessed metallic regions for more efficient electron emission or collection. Furthermore, evaporation and surface diffusion of matrix oxides may provide oxygen enhancement of cesium adsorption and work function lowering at both the collecting and emitting electrode surfaces of the TEC. Finally, the high work function oxide matrix or oxide-metal interfaces may provide efficient surface ionization of cesium for space-charge reduction in the device. The authors are investigating two types of ceramic/metal composite materials. One type is a directionally solidified eutectic consisting of a bulk oxide matrix such as UO2 or stabilized ZrO2 with parallel metal fibers (W) running through the oxide being exposed at the surface by cutting perpendicular to the fiber direction. The second type of material, called a surface eutectic, consists of a refractory substrate (Mo) with a thin layer of deposited and segregated material (Mo-Cr2O3-A12O3) on the surface. The final configuration of this layer is an oxide matrix with metallic islands scattered throughout

  19. Effects of Surface Morphology ZnAl2O4 of Ceramic Materials on Osteoblastic Cells Responses

    International Nuclear Information System (INIS)

    Ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. The purpose of this study was to investigate the effect of surface morphology of nano structure thin films of ZnAl2O4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl2O4 prepared by chemical coprecipitation reaction on the in vitro cell adhesion, viability, and cell-material interactions of osteoblastic cells. Our result showed that cell attachment was significantly enhanced from 60 to 80% on the ZnAl2O4 nano structured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nano structure ceramic improves cell-material interaction with enhanced spreading and filopodia with multiple cellular extensions on the surface of the ceramic and enhancing cell viability/proliferation in comparison with bulk ceramic surfaces used as control. Altogether, these results suggest that zinc aluminate nano structured materials have a great potential to be used in dental implant and bone substitute applications.Ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. The purpose of this study was to investigate the effect of surface morphology of nano structure thin films of ZnAl2O4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl2O4 prepared by chemical coprecipitation reaction on the in vitro cell adhesion, viability, and cell-material interactions of osteoblastic cells. Our result showed that cell attachment was significantly enhanced from 60 to 80% on the ZnAl2O4 nano structured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nano structure ceramic improves cell-material

  20. Analysis of the potential for ductile mode machining of ferroelectric ceramic materials

    International Nuclear Information System (INIS)

    Ferroelectric ceramics and single crystals have attained an enormous importance in an ever-widening range of technological applications. Their exceptional combination of properties include strong piezoelectric, pyroelectric and electro-optic effects. One of the most important and widely-used groups of ferroelectric ceramics is the solid solution form of the lead zirconate titanate (PZT) family. A wide range of products relies on the high-precision fabrication of components using ferroelectric ceramics, including: ultrasonic medical imaging transducers, ink jet printing heads, pyroelectric IR detection arrays and optical modulation systems. Not only is precision important, but also the degree of sub-surface damage must be minimised because this is known to compromise performance by engendering de-poling. This effect also leads to in-service problems due to fast ageing and noise effects caused by the movement of damage-induced domain walls and cracks. The contemporary technology which has been used to machine these materials has been grinding and diamond sawing followed by lapping and polishing

  1. Alternative technological approach for synthesis of ceramic pigments by waste materials recycling

    International Nuclear Information System (INIS)

    Alternative technological approach is proposed enabling utilization of raw materials from an oil refinery, such as waste guard layers from reactors. Reagent grade and purified MgO, Cr2O3, Fe2O3, and nitric acid (HNO3), were used as additional precursors. The homogeneous mixtures obtained were formed into pellets and sintered at different temperatures. The main phase was proved by X-ray phase analysis (XRD) and compared to ICPDS database. The main phase in the ceramics synthesized was solid solution of spinel MgAl2O4 and magnesiochromite. These minerals are classified as chromspinelide MgCr1.2Al0.4Fe0.4O4 and alumochromite MgCr1.6Al0.4O4. Additional SEM observations, combined with EDX analysis were performed, evincing agglomeration at lower temperatures, followed by agglomerate crumbling, at elevated calcination temperature. The complete transformation of initial precursors into the final ceramic compounds was found to occur at 800 degree centigrade 1 h. The ceramic samples synthesized had high density of 1.72-1.93 g/cm3 and large absorption area - 32.93% which is probably due to the high porosity of the sample. (Author)

  2. Characterization of ceramic masses using raw material of Para, Brazil: kaolin in natura

    International Nuclear Information System (INIS)

    The incorporation rejects to the mixtures has if shown viable in the reduction of the environmental liability and for the obtaining of a better quality of the ceramic mass. In the present work, is tried to study the potentiality of the use of ceramic formulations with the addition of kaolin in natura to the clays. Formulations with two clays of the area of the municipal district of Maraba with addition of up to 60% in kaolin weight were prepared and characterized. For the determination of the physical and mechanical properties proof bodies were made by prensagem uniaxial and later burned in temperature from 900 to 1200 deg C with landing of 3 hours. The raw materials were characterized through diffraction of rays X (DRX) and thermogravimetric analysis. The proof bodies prepared were used for determination of the lineal retraction (RL), absorption of water, apparent porosity, apparent density, loss to the fire and rupture module the flexing. The results were satisfactory for the smallest kaolin tenors in the ceramic mass, and the mass with 20% presented rupture module elevated, in the temperature of 1200 deg C. (author)

  3. Alternative technological approach for synthesis of ceramic pigments by waste materials recycling

    Energy Technology Data Exchange (ETDEWEB)

    Doynov, M.; Dimitrov, T.; Kozhukharov, S.

    2016-05-01

    Alternative technological approach is proposed enabling utilization of raw materials from an oil refinery, such as waste guard layers from reactors. Reagent grade and purified MgO, Cr{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, and nitric acid (HNO{sub 3}), were used as additional precursors. The homogeneous mixtures obtained were formed into pellets and sintered at different temperatures. The main phase was proved by X-ray phase analysis (XRD) and compared to ICPDS database. The main phase in the ceramics synthesized was solid solution of spinel MgAl{sub 2}O{sub 4} and magnesiochromite. These minerals are classified as chromspinelide MgCr{sub 1}.2Al{sub 0}.4Fe{sub 0}.4O{sub 4} and alumochromite MgCr{sub 1}.6Al{sub 0}.4O{sub 4}. Additional SEM observations, combined with EDX analysis were performed, evincing agglomeration at lower temperatures, followed by agglomerate crumbling, at elevated calcination temperature. The complete transformation of initial precursors into the final ceramic compounds was found to occur at 800 degree centigrade 1 h. The ceramic samples synthesized had high density of 1.72-1.93 g/cm{sup 3} and large absorption area - 32.93% which is probably due to the high porosity of the sample. (Author)

  4. Viability of utilization of waste materials from ceramic products in precast concretes

    Directory of Open Access Journals (Sweden)

    Sánchez de Rojas, M. I.

    2001-12-01

    Full Text Available The recycled and re-valuation process of waste materials involves studies lead to a deep acknowledges of them, finding applications for their intended use. The waste materials from ceramic products can be recycled into the construction sector, as arid or pozzolanic materials. The current work deals with the incorporation of ceramic materials in these two different ways, checking the behaviour of the elaborated mortar by mean of laboratory tests. Also, tests are developed in factory, using these as components for precast concrete tiles.

    Todo proceso de reciclado y revalorización de residuos implica estudios encaminados a un conocimiento profundo de los mismos, de forma que se busquen aplicaciones concretas de uso. Los materiales de desecho procedentes de productos cerámicos pueden ser reciclados dentro del sector de la construcción, ya sea como áridos o como materiales puzolánicos. El presente trabajo aborda la incorporación de materiales cerámicos desde estas dos vertientes, comprobando, en cada caso, el comportamiento de los morteros elaborados mediante ensayos de laboratorio. También se llevan a cabo pruebas en fábrica, siendo utilizados como componentes en prefabricados de hormigón.

  5. Investigation of metallic, ceramic, and polymeric materials for engineered barrier applications in nuclear-waste packages

    International Nuclear Information System (INIS)

    An effort to develop licensable engineered barrier systems for the long-term (about 1000 yr) containment of nuclear wastes under conditions of deep continental geologic disposal has been underway at Pacific Northwest Laboratory since January 1979, under the auspices of the High-Level Waste Immobilization Program. In the present work, the barrier system comprises the hard or structural elements of the package: the canister, the overpack(s), and the hole sleeve. A number of candidate metallic, ceramic, and polymeric materials were put through mechanical, corrosion, and leaching screening tests to determine their potential usefulness in barrier-system applications. Materials demonstrating adequate properties in the screening tests will be subjected to more detailed property tests, and, eventually, cost/benefit analyses, to determine their ultimate applicability to barrier-system design concepts. The following materials were investigated: two titanium alloys of Grade 2 and Grade 12; 300 and 400 series stainless steels, Inconels, Hastelloy C-276, titanium, Zircoloy, copper-nickel alloys and cast irons; total of 14 ceramic materials, including two grades of alumina, plus graphite and basalt; and polymers such as polyamide-imide, polyarylene, polyimide, polyolefin, polyphenylene sulfide, polysulfone, fluoropolymer, epoxy, furan, silicone, and ethylene-propylene terpolymer (EPDM) rubber. The most promising candidates for further study and potential use in engineered barrier systems were found to be rubber, filled polyphenylene sulfide, fluoropolymer, and furan derivatives

  6. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Energy Technology Data Exchange (ETDEWEB)

    Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T [Research Unit of Advanced Ceramic, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Padipatvuthikul, P, E-mail: raayaa_chula@hotmail.com [Faculty of Dentistry, Srinakharinwirot University, Bangkok (Thailand)

    2011-10-29

    Silicon nitride (Si{sub 3}N{sub 4}) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si{sub 3}N{sub 4} ceramic as a dental core material. The white Si{sub 3}N{sub 4} was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si{sub 3}N{sub 4} ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si{sub 3}N{sub 4} specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (<150 micrometer, Pyrex) with 5 wt% of zirconia powder (3 wt% Y{sub 2}O{sub 3} - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si{sub 3}N{sub 4} specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10{sup -6} deg. C{sup -1}, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  7. Vitreous bond CBN high speed and high material removal rate grinding of ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Shih, A.J.; Grant, M.B.; Yonushonis, T.M. [Cummins Engine Co., Inc., Columbus, IN (United States); Morris, T.O.; McSpadden, S.B. [Oak Ridge National Lab., TN (United States)

    1998-08-01

    High speed (up to 127 m/s) and high material removal rate (up to 10 mm{sup 3}/s/mm) grinding experiments using a vitreous bond CBN wheel were conducted to investigate the effects of material removal rate, wheel speed, dwell time and truing speed ratio on cylindrical grinding of silicon nitride and zirconia. Experimental results show that the high grinding wheel surface speed can reduce the effective chip thickness, lower grinding forces, enable high material removal rate grinding and achieve a higher G-ratio. The radial feed rate was increased to as high as 0.34 {micro}m/s for zirconia and 0.25 {micro}m/s for silicon nitride grinding to explore the advantage of using high wheel speed for cost-effective high material removal rate grinding of ceramics.

  8. Ceramic glossary

    International Nuclear Information System (INIS)

    This book is a 2nd edition that contains new terms reflecting advances in high technology applications of ceramic materials. Definitions for terms which materials scientists, engineers, and technicians need to know are included

  9. Dental ceramics: An update

    OpenAIRE

    Shenoy Arvind; Shenoy Nina

    2010-01-01

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

  10. Structural, microstructural and impedance spectroscopy study of functional ferroelectric ceramic materials based on barium titanate

    International Nuclear Information System (INIS)

    The differences between the physical properties of barium titanate BaTiO3 and newly obtained BaHfxTi1-xO3 were identified. These ceramics were prepared by solid-phase reaction from simple oxides and carbonates using the conventional method. The structure and morphology of investigated samples were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The application of impedance spectroscopy made possible to characterize of these materials in the terms of electrical properties

  11. Migration of Toxic Metals from Ceramic Food Packaging Materials into Acid Food Simulants

    OpenAIRE

    Zhanhua Dong; Lixin Lu; Zhigang Liu; Yali Tang; Jun Wang

    2014-01-01

    Long-term extraction experiments were carried out on glazed tile specimens with 4 and 10% (v/v) acetic acid, 1% (w/v) citric acid, and 1% (v/v) lactic acid solution in three temperature conditions (20, 40, and 60°C) to investigate the effect of temperature and pH value on extraction of lead, cobalt, nickel, and zinc from ceramic food packaging materials and to study the extraction kinetics of toxic metals. Results showed that except at 60°C the amount of extraction of lead, cobalt, nickel, an...

  12. Modelling of Grain Growth Kinetics in Porous Ceramic Materials under Normal and Irradiation Conditions

    Directory of Open Access Journals (Sweden)

    Mikhail S. Veshchunov

    2009-09-01

    Full Text Available Effect of porosity on grain growth is both the most frequent and technologically important situation encountered in ceramic materials. Generally this effect occurs during sintering, however, for nuclear fuels it also becomes very important under reactor irradiation conditions. In these cases pores and gas bubbles attached to the grain boundaries migrate along with the boundaries, in some circumstances giving a boundary migration controlled by the movement, coalescence and/or sintering of these particles. New mechanisms of intergranular bubble and pore migration which control the mobility of the grain boundary under normal and irradiation conditions are reviewed in this paper.

  13. Cell response of calcium phosphate based ceramics, a bone substitute material

    Directory of Open Access Journals (Sweden)

    Juliana Marchi

    2013-01-01

    Full Text Available The aim of this study was to characterize calcium phosphate ceramics with different Ca/P ratios and evaluate cell response of these materials for use as a bone substitute. Bioceramics consisting of mixtures of hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP powders in different proportions were pressed and sintered. The physical and chemical properties of these bioceramics were then characterized. Characterization of the biological properties of these materials was based on analysis of cell response using cultured fibroblasts. The number of cells attached to the samples was counted from SEM images of samples exposed to cell culture solution for different periods. These data were compared by analysis of variance (ANOVA complemented by the Tukey's test. The TCP sample had higher surface roughness and lower density. The adherence and growth of FMM1 cells on samples from all groups was studied. Even though the different calcium based ceramics exhibited properties which made them suitable as bone substitutes, those with higher levels of β-TCP revealed improved cell growth on their surfaces. These observations indicated two-phase calcium phosphate based materials with a β-TCP surface layer to be a promising bone substitute.

  14. Broadband mid-infrared wavelength conversion laser based on Cr2+ doped ceramic materials

    Science.gov (United States)

    Shang, Yaping; Yin, Ke; Li, Xiao; Wang, Peng; Xu, Xiaojun

    2015-10-01

    Broadband mid-infrared lasers are desirable for pretty important applications in fields of environmental protection, medical treatment, military applications, scientific, and other domains. Recently, super-continuum laser sources have achieved striking development. However, limited by the substrate materials, the output power scaling of the broadband mid-infrared fiber laser sources could not be increased drastically, especially for the long wavelength region. In this paper, we reported an experimental study about the broadband mid-infrared lasers based on Cr2+ doped II-VI ceramic materials, by using of a super-continuum laser source developed by our groups operating at 1550~2130nm with 200mW output power. The result suggested that the near-infrared spectral component of the super-continuum source was deeply absorbed by transition metal doped zinc chalcogenides ceramic materials, meanwhile the mid-infrared part, however, had been enhanced significantly by this new "power amplifier." Actually single-pass amplification efficiency was very limited. The best way to solve this problem was multi-pass amplification systems. We had shown an initial proof of this assumption by a double-pass experiments, the result was consistent with expected effect. Above all, the spectrum shaping from short wavelength to long wavelength was obtained. The innovative discovery had laid a solid foundation for high power, high efficiency, broadly tunable mid-infrared solid state lasers.

  15. Mechanical and tribological properties of ceramic-matrix friction materials with steel fiber and mullite fiber

    International Nuclear Information System (INIS)

    Highlights: • Interaction of mixing the steel and mullite fibers can improve the mechanical properties. • Mixing the steel and mullite fibers can also improve friction stability. • Friction coefficient increases with increasing additional mullite fiber content. • Ceramic-matrix friction material shows sever fade due to mullite fibers agglomerated. - Abstract: The purpose of the present work was to investigate and compare the mechanical and tribological behaviors of ceramic-matrix friction material (CMFM) with steel fiber (SF), mullite fiber (MF), and mixing SF and MF. The CMFM was prepared by hot-pressing sintering, and the tribological behaviors were determined using a constant speed friction tester. The worn surfaces and wear debris were observed by a scanning electron microscopy (SEM). Experiment results show that the combination of SF and MF can improve the mechanical properties that each single fiber does not have. The sever fade for the specimen reinforced by single MF during the whole friction testing can be attributed to the poor interface cohesive strength between MF and matrix. Mixing the SF and MF can improve the friction stability, and the friction coefficients for friction material with a mixture of the SF and MF increases with increasing MF content. For all specimens, increasing in the friction temperatures result in the increase of wear rates

  16. Fracture resistance of endodontically treated teeth restored with ceramic inlays and different base materials.

    Science.gov (United States)

    Saridag, Serkan; Sari, Tugrul; Ozyesil, Atilla Gokhan; Ari Aydinbelge, Hale

    2015-01-01

    This study evaluated the fracture resistance of endodontically treated teeth restored with different base materials and mesioocclusal-distal (MOD) ceramic inlays. Fifty mandibular molars were assigned into five groups (n=10 per group). Group1 (control) comprised intact molar teeth without any treatment. Teeth in other groups were subjected to root canal treatment and restored with MOD ceramic inlays on different base materials. In Group 2, base material was zinc phosphate cement; Group 3's was glass ionomer cement; Group 4's was composite resin, and Group 5's was composite resin reinforced with fiber. Finally, a continuous occlusal load was applied until fracture occurred. Mean fracture resistance of Group 1 (3,027 N) was significantly higher than the other groups (890, 1,070, 1,670, 1,226 N respectively). Fracture resistance of Group 4 was statistically comparable with Group 5 and significantly higher than Groups 2 and 3 (pinlay restorations could affect the fracture resistance of endodontically treated teeth. PMID:25740162

  17. Gamma and proton induced degradation in ceramics materials - A proposal for EUROATOM Fusion Project

    International Nuclear Information System (INIS)

    Ceramic materials will play very important roles in developing fusion reactors, where they will be used under heavy irradiation environment (neutrons, gamma-rays, helium and other ions) for substantial periods for the first time. Our programme intends to form a part of the existing on-going ceramics programmes to assess the suitability of SiO2 based materials for both diagnostic and remote handling application. Our proposal focuses on comparison of the ionization and displacement induced damage (influence on the UV and visible optical transmission properties) and on radiation enhanced diffusion of hydrogen isotopes in these materials, in cooperation with CIEMAT Madrid and SCK/CEN Mol. Our irradiation facilities are : IRASM with a 200 kCi Co-60 source, of minimum 2kGray/h, ethanol chlorine benzene and ESR dosimetry - HVEC 8 MV TANDEM protons up to 16 MeV and 200 nA and 600 kV DISKTRON H isotopes up to 600 keV at tens of μA. (authors)

  18. Study of parameters of heat treatment in obtaining glass ceramic materials with addition of the industrial waste

    International Nuclear Information System (INIS)

    The production of materials from crystallization of glass, called glass ceramic, have proved interesting by the possibility of development of different microstructures, with reduced grain size and the presence of residual amorphous phase in different quantities. The method that uses the differential thermal analysis (DTA) provides research on the material properties over a wide temperature range, it's widely applied to crystallization processes of glass ceramic materials. Within this context, this paper aims to study the kinetics of nucleation and crystal growth in glass ceramic materials in the system SiO2- Al2O3-Li2O, obtained with the addition of mineral coal bottom ash as source of aluminosilicates, through the technique of differential thermal analysis. (author)

  19. Method for preparing rare earth-barium-cuprate pre-ceramic resins and superconductive materials prepared therefrom

    International Nuclear Information System (INIS)

    This patent describes a method of making a pre-ceramic material capable of being converted into an electrically superconductive ceramic material having the general formula ABa2Cu3O7-x where A is a rare earth metal and x is from 0 to 0.5. It comprises refluxing stoichiometric amounts of a first solution comprising a rare earth isopropoxide and barium isopropoxide in isopropanol under a dry, inert atmosphere; adding to the first solution a stoichiometric amount of a second solution comprising copper ethylhexanoate in isopropanol; refluxing the first and second solutions to obtain a precipitate; adding to the precipitate a quantity of a first solvent comprising water and isopropanol; concentrating the homogeneous solution by removing a sufficient amount of the first solvent to produce a viscous or dry pre-ceramic resinous material; softening or dissolving the pre-ceramic resinous material in a second solvent comprising a binary mixture of a polar solvent and a nonpolar solvent to obtain a desired viscosity; and forming the viscous pre-ceramic material into the desired product shape

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

    International Nuclear Information System (INIS)

    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 γ-ray spectrum are reported. (author)

  1. 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)

  2. Low-Activation structural ceramic composites for fusion power reactors: materials development and main design issues

    International Nuclear Information System (INIS)

    This paper is devoted to the development of advanced Low-Activation Materials (LAMs) with favourable short-term activation characteristics for the use as structural materials in a fusion power reactor (in order to reduce the risk associated with a major accident, in particular those related with radio-isotopes release in the environment), and to try to approach the concept of an inherently safe reactor. LA Ceramics Composites (LACCs) are the most promising LAMs because of their relatively good thermo-mechanical properties. At present, SiC/SiC composite is the only LACC considered by the fusion community, and therefore is the one having the most complete data base. The preliminary design of a breeding blanket using SiC/SiC as structural material indicated that significant improvement of its thermal conductivity is required. (orig.)

  3. Low-activation structural ceramic composites for fusion power reactors: materials development and main design issues

    International Nuclear Information System (INIS)

    Development of advanced Low-Activation Materials (LAMs) with favourable short-term activation characteristics is discussed, for the use as structural materials in a fusion power reactor (in order to reduce the risk associated with a major accident, in particular those related with radio-isotopes release in the environment), and to try to approach the concept of an inherently safe reactor. LA Ceramics Composites (LACCs) are the most promising LAMs because of their relatively good thermo-mechanical properties. At present, SiC/SiC composite is the only LACC considered by the fusion community, and therefore is the one having the most complete data base. The preliminary design of a breeding blanket using SiC/SiC as structural material indicated that significant improvement of its thermal conductivity is required. (author) 11 refs.; 3 figs

  4. Theoretical Studies on the Electronic Structures and Properties of Complex Ceramic Crystals and Novel Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ching, Wai-Yim

    2012-01-14

    This project is a continuation of a long program supported by the Office of Basic Energy Science in the Office of Science of DOE for many years. The final three-year continuation started on November 1, 2005 with additional 1 year extension to October 30, 2009. The project was then granted a two-year No Cost Extension which officially ended on October 30, 2011. This report covers the activities within this six year period with emphasis on the work completed within the last 3 years. A total of 44 papers with acknowledgement to this grant were published or submitted. The overall objectives of this project are as follows. These objectives have been evolved over the six year period: (1) To use the state-of-the-art computational methods to investigate the electronic structures of complex ceramics and other novel crystals. (2) To further investigate the defects, surfaces/interfaces and microstructures in complex materials using large scale modeling. (3) To extend the study on ceramic materials to more complex bioceramic crystals. (4) To initiate the study on soft condensed matters including water and biomolecules. (5) To focus on the spectroscopic studies of different materials especially on the ELNES and XANES spectral calculations and their applications related to experimental techniques. (6) To develop and refine computational methods to be effectively executed on DOE supercomputers. (7) To evaluate mechanical properties of different crystals and those containing defects and relate them to the fundamental electronic structures. (8) To promote and publicize the first-principles OLCAO method developed by the PI (under DOE support for many years) for applications to large complex material systems. (9) To train a new generation of graduate students and postdoctoral fellows in modern computational materials science and condensed matter physics. (10) To establish effective international and domestic collaborations with both experimentalists and theorists in materials

  5. Bone cell-materials interaction on alumina ceramics with different grain sizes

    International Nuclear Information System (INIS)

    The objective of this work was to study adhesion, proliferation and differentiation of osteoblast cells (OPC1) on alumina ceramic, a bio-inert material. Alumina ceramic with different average grain sizes, 1 μm and 12 μm, respectively, were used in as-prepared condition without any grinding and polishing to understand the influence of grain size on cell-material interactions. Scanning electron microscopy and confocal imaging were used to study attachment, adhesion and differentiation of OPC1 cells. Cells attached, proliferated and differentiated well on both the substrates. Adhesion of cells, as assessed by observing the production of vinculin, was found to be a consistent phenomenon on both the substrates. On day 5 of cell culture, significant cell-attachment was observed and vinculin was detected throughout cytoplasm. MTT assay showed that proliferation of OPC1 cells was consistently higher in the case of 12 μm-alumina. Cells of different morphology, nodular, plate-like as well as elongated, were found to get anchored at grains, grain boundaries as well as pores. On day 16, there were clear signs of mineralization as well. Over all, alumina with average grain size of 12 μm showed better cell-attachment, growth and differentiation compared to 1 μm grain size samples.

  6. Study of radiation stability of new poly-phase ash-ceramic materials

    International Nuclear Information System (INIS)

    Study of physico-mechanical and thermophysical properties of ash-ceramics after repeated irradiation by accelerated electrons beams under different regimes is carried out. Ash of Almaty Thermal Power Plant (Almatinskaya GREhS) and clay of Ajnabulak deposit serve as objects of testing . Samples after preliminary drying have been burnt in electric crucible furnace at maximum temperature 1100 deg C. Samples with different densities (1100-1400 kg/m3) were got with help method of different rate of treatment and compressing of forming ash-clay mixture. Pressure strength for burnt samples made up 12.5-17.5 MPa. Examined samples irradiated a few times with following doses: 9.45·106; 27·106; 81·106 Gy. Thermophysical and physico-technical features of samples have been studied after each irradiation. Comparison of received results with data of non-irradiated samples shows, that evident changes in structure and properties of testing materials have been not observed. It is concluded, that new ash-ceramic materials have sufficient radiation stability

  7. Migration of Toxic Metals from Ceramic Food Packaging Materials into Acid Food Simulants

    Directory of Open Access Journals (Sweden)

    Zhanhua Dong

    2014-01-01

    Full Text Available Long-term extraction experiments were carried out on glazed tile specimens with 4 and 10% (v/v acetic acid, 1% (w/v citric acid, and 1% (v/v lactic acid solution in three temperature conditions (20, 40, and 60°C to investigate the effect of temperature and pH value on extraction of lead, cobalt, nickel, and zinc from ceramic food packaging materials and to study the extraction kinetics of toxic metals. Results showed that except at 60°C the amount of extraction of lead, cobalt, nickel, and zinc had linear dependence on time at longer times and removal of these toxic metals under other conditions increased linearly with the square root of the time, indicating a diffusion-controlled process. The amount of these toxic metals leached out from ceramic food packaging materials into the leachate, and the leaching rate increased with temperature and decreased with pH value of the food simulants. In addition, among these four toxic metals lead was the least leachable element, and nickel was the most leachable one. Disagreement between the ratios of the oxide of lead, cobalt, nickel, and zinc in the glaze and their release in the leachate suggested that extraction of these toxic metals was an incongruent dissolution process.

  8. EXOTIC-7: Irradiation of ceramic breeder materials to high lithium burnup

    International Nuclear Information System (INIS)

    The EXOTIC-7 irradiation experiment in the High Flux Reactor (HFR) at Petten has been completed. Its aim has been to investigate the effects of high lithium-burnup on the mechanical stability and tritium release characterisitcs of candidate ceramic breeder materials, originating from the Fusion Programmes of CEA, FZK, ENEA, AECL and ECN. The tested ceramic breeder materials were pellets of Li2ZrO3, LiAlO2 and Li8ZrO6 and pebbles of Li4SiO4 and Li2ZrO3, with a variety of characteristics, like grain size and porostiy. The test matrix provided the simultaneous irradiation of eight independent capsules with on-line tritium monitoring. Two capsules containd a mixture of Li4SiO4 and beryllium pebbles. The experimental design, sample loading and main riiadiation parameters are described. Some PIE results and analysis of in-situ tritium release behaviour are presented. (orig.)

  9. Studies on properties of low atomic number ceramics as limiter materials for fusion applications

    International Nuclear Information System (INIS)

    The present study deals with thermal shock and erosion-redeposition behaviour of low-Z-bulk-ceramics: SiC, SiC + Si, SiC + 3% Al, SiC + 2% AlN, AlN, Si3N4, BN with graphite as reference material. Also included are substrate-coating systems: TiC coated graphite, Cr2C3 coated graphite and TiN on Inconel. The properties are being investigated by electron beam and in-pile fusion machine tests in the KFA-Tokamak machine Textor. The electron-beam tests showed that sublimation was the dominant damaging effect for graphite, BN and SiN4. Materials with mediocre thermo-mechanical properties, such as SiC and AlN, showed cracks. The highest energy density values were tolerated by specimens of SiC alloyed with 2% AlN. In general, the in pile behaviour of the ceramics was comparable with the electron beam tests: BN and SiC + 2% AlN are at present regarded as the prime candidates for future irradiation tests. (author)

  10. A mesomechanical analysis of the deformation and fracture in polycrystalline materials with ceramic porous coatings

    Science.gov (United States)

    Balokhonov, R. R.; Zinoviev, A. V.; Romanova, V. A.; Batukhtina, E. E.

    2015-10-01

    The special features inherent in the mesoscale mechanical behavior of a porous ceramic coating-steel substrate composite are investigated. Microstructure of the coated material is accounted for explicitly as initial conditions of a plane strain dynamic boundary-value problem solved by the finite difference method. Using a mechanical analogy method, a procedure for generating a uniform curvilinear finite difference computational mesh is developed to provide a more accurate description of the complex grain boundary geometry. A modified algorithm for generation of polycrystalline microstructure of the substrate is designed on the basis of the cellular automata method. The constitutive equations for a steel matrix incorporate an elastic-plastic model for a material subjected to isotropic hardening. The Hall-Petch relation is used to account for the effect of the grain size on the yield stress and strain hardening history. A brittle fracture model for a ceramic coating relying on the Huber criterion is employed. The model allows for crack nucleation in the regions of triaxial tension. The complex inhomogeneous stress and plastic strain patterns are shown to be due to the presence of interfaces of three types: coating-substrate interface, grain boundaries, and pore surfaces.

  11. Thermal conductivity deg.radation of ceramic materials due to low temperature, low dose neutron irradiation

    International Nuclear Information System (INIS)

    The thermal conductivity degradation due to low-temperature neutron irradiation is studied and quantified in terms of thermal resistance terms. Neutron irradiation is assumed to have no effect on umklapp scattering. A theoretical model is presented to quantify the relative phonon-scattering effectiveness of the three dominant defect types produced by neutron irradiation: point defects, dislocation loops and voids. Several commercial ceramics have been irradiated with fission reactor fast neutrons at low temperatures to produce defects. Materials include silicon carbide, sapphire, polycrystalline alumina, aluminum nitride, silicon nitride, beryllium oxide, and a carbon fiber composite. The neutron dose corresponded to 0.001 and 0.01 displacements per atom (dpa) for a ∼60 deg. C irradiation and 0.01 and 0.1 dpa for a ∼300 deg. C irradiation. Substantial thermal conductivity degradation occurred in all of the materials except BeO following irradiation at 60 deg. C to a dose of only 0.001 dpa. The data are discussed in terms of the effective increase in thermal resistance caused by the different irradiation conditions. Evidence for significant point defect mobility during irradiation at 60 and 300 deg. C was obtained for all of the ceramics. The thermal stability of the radiation defects was investigated by isochronal annealing up to 1050 deg. C

  12. Isotope exchange reactions on ceramic breeder materials and their effect on tritium inventory

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, M.; Baba, A. [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering; Kawamura, Y.; Nishi, M.

    1998-03-01

    Though lithium ceramic materials such as Li{sub 2}O, LiAlO{sub 2}, Li{sub 2}ZrO{sub 3}, Li{sub 2}TiO{sub 3} and Li{sub 4}SiO{sub 4} are considered as breeding materials in the blanket of a D-T fusion reactor, the release behavior of the bred tritium in these solid breeder materials has not been fully understood. The isotope exchange reaction rate between hydrogen isotopes in the purge gas and tritium on the surface of breeding materials have not been quantified yet, although helium gas with hydrogen or deuterium is planned to be used as the blanket purge gas in the recent blanket designs. The mass transfer coefficient representing the isotope exchange reaction between H{sub 2} and D{sub 2}O or that between D{sub 2} and H{sub 2}O in the ceramic breeding materials bed is experimentally obtained in this study. Effects of isotope exchange reactions on the tritium inventory in the bleeding blanket is discussed based on data obtained in this study where effects of diffusion of tritium in the grain, absorption of water in the bulk of grain, and adsorption of water on the surface of grain, together with two types of isotope exchange reactions are considered. The way to estimate the tritium inventory in a Li{sub 2}ZrO{sub 3} blanket used in this study shows a good agreement with data obtained in such in-situ experiments as MOZART, EXOTIC-5, 6 and TRINE experiments. (author)

  13. Determination of Natural Radioactivity and Gamma Radiation dose in Ceramic Materials Containing Fly Ash Developed in Israel

    International Nuclear Information System (INIS)

    The ionizing radiation dose from building materials containing fly ash (FA) has been studied. Ceramic products, plates, blocks and bricks containing fly ash have been studied and compared to other construction materials for both natural occurring radioactive materials (NORM) content, radon exhalation rate and gamma radiation dose. The utilization of fly ash (FA) as resources was studied for many years in different areas such as, ceramic products, in agriculture, paints, plastic industry. Usually, ceramic blocks or blocks containing a mixture of clay and fly ash, are fired in a metallurgical furnace at selected temperatures of 750 degrees C - 950 degrees C. In order to preserve the environment, from large quantities of FA and BA (bottom ash) produced during the combustion of coal for energy production, the application of this pollutant (FA) was experimentally investigated by utilizing it in manufacturing of ceramic products recently developed in Israel as building materials. During the last years there has been an increased awareness of the radiological health hazards due to ionizing radiation emitted by building materials including those containing fly ash. Much research has been carried out in order to determine the correlation between the concentration of radioactive materials in building materials and the external radiation doses to which the general public is exposed

  14. Optimisation of alumina - silicon carbide dispersions and the fabrication of nanocomposite ceramic materials

    International Nuclear Information System (INIS)

    Ceramic nanocomposite materials have been reported to have good mechanical properties. However, close control of the fabrication process must be maintained in order to achieve good dispersion of the secondary phase within the matrix which is essential if these good properties are to be obtained. To date, only powder processing in organic media has been reported. The processing conditions of alumina-silicon carbide nanocomposites have been investigated. Processing was carried out in aqueous and organic media. Optimisation of dispersion involved measurement of the zeta potential of alumina and silicon carbide aqueous slurries, selection of organic mixing media as well as the type and quantity of dispersing agent. Dense materials were obtained by hot pressing of the optimised powders. Microstructural analysis and mechanical property assessment have been carried out. A strength improvement of 30% was achieved by the addition of 5 vol% SiC to alumina. (orig.)

  15. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL

    2014-01-01

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

  17. Effect of Internal Electrode Materials in Multilayer Ceramic Capacitors on Electrical Properties

    Science.gov (United States)

    Takeoka, Shinsuke; Mizuno, Youichi

    2011-09-01

    The influence of internal electrode materials on electrical properties in multilayer ceramic capacitors (MLCCs) fabricated by low-temperature co-firing was discussed. The lifetime of MLCCs is considerably improved by using copper rather than nickel internal electrodes. The leakage current density for various dc electric fields (I-V characteristics) and thermally stimulated current (TSC) were measured to investigate the lifetime improvement mechanism. The I-V characteristics demonstrated that the leakage current in a high dc electric field was suppressed in the case of copper internal electrodes. The TSC spectra demonstrated that the internal electrode materials hardly influenced the quantity of polarization charge formed by the electromigration of oxygen vacancies. Therefore, we considered that the improved lifetime by using copper internal electrodes was mainly due to the suppressed leakage current in a high dc electric field, not the quantity of polarization charge formed by the electromigration of oxygen vacancies in the MLCCs.

  18. Novel Processing of Unique Ceramic-Based Nuclear Materials and Fuels

    International Nuclear Information System (INIS)

    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 components 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.

  19. Progress of in-situ produced functionally graded hard materials (hardmetals and ceramics) for tool applications

    International Nuclear Information System (INIS)

    Hard together with tough has been long the goal of tool scientists and engineers. Coated tools combine high wear and high toughness together and have been successfully used today. However, the coating thickness is limited because of large different between substrate and coating, additional cost is need for coating processing (CVD or PVD), and furthermore, in some cases such as in mining applications coated tools are not suitable. Recently, the concept of Functionally graded materials (FGMs) has spread word-wide during the past four international symposiums held in Sendai, Japan (1990), San Francisco, USA (1992), Lausanne, Switzerland (1994) and Tsukuba, Japan (1996). The idea of graded compositions, microstructures and functions has attracted the attention of many scientists, researchers and engineers for its boundless scope in materials science and engineering. FGMs materials are usually prepared by sintering of pre-layered green powder compacts. This processing is not suitable for tool producers because of its complicated process and additional costs. By studying phase diagrams, phase stability, phase equilibria and metallurgical reactions during sintering, graded WC-Co hardmetals and graded sialon ceramics (Si3N4), with increased Co contents and increased β/α phase ratio inwards respectively, have been in-situ produced recently from homogenous powder compact. The properties (functions) vary gradually from surface to center (core) due to compositional graduations. The graded WC-Co hardmetals feature 3 zone structures and have been successfully used in industry. The graded sialon, ceramics are only recently fabricated by Austrian Research Center Seibersdorf first and characterize high wear α-Sialon surface and high tough β-sialon core. This work presents progress of the above mentioned functionally graded tool materials. (author)

  20. Ceramic materials in hydroelectric power plants - testing and working out method descriptions. Prestudy; Keramiska material i vattenkraftanlaeggningar - test och utarbetande av metodbeskrivning. Foerstudie

    Energy Technology Data Exchange (ETDEWEB)

    Forssander, Maerit (TerraCorrosion AB (SE)); Persson, Charlotte (EnergoRetea, Stockholm (SE)); Carlsson, Roger (Vattenfall Power Consultant, Stockholm (SE)); Edwardson, Wille (Jaemtkontroll, Hammerdal (SE)); Johansson, Martin (Skellefteaa Kraft (SE)); Westerlund, Erik (Fortum Power and Heat OY (FI))

    2008-01-15

    Using ceramic materials for anti-corrosion painting in Swedish hydro power plants has been done with different results. In some cases it has performed well but in other it has failed. In only some cases the tests has been followed up rigorously to learn more about the process. The result from the interviews with the user and manufacturers is that there are cases where the use of ceramics in the hydro power plants will be economically favourable. The materials are there but they have to be tested in every single application before general recommendations can be done. A literature survey has been performed. Experiences from tests with ceramics in hydro power plants in Sweden have been summarised. Manufacturers on the Swedish market have been interviewed. The results from the literature survey showed that no published result was to be found of using ceramics in hydro electric power plants in the world. It is mentioned somewhere that Three Gorges in China have been using ceramics but no results was found. The conclusion is that even though the use of ceramics in hydro power plants can be economically favourable more tests has to be done. Those tests can be done together with the manufacturers in Sweden

  1. Sensitivity Analysis of the Material Parameters of the Ceramics on the Inner Radius of the Hip Joint Endoprosthesis Head

    Czech Academy of Sciences Publication Activity Database

    Fuis, Vladimír; Janíček, Přemysl

    Warsawa : Springer, 2015 - (Jablonski, R.; Brezina, T.), s. 123-128 ISBN 978-3-319-23921-7. ISSN 2194-5357. - (Advances in Intelligent Systems and Computing. 393). [Mechatronics 2015. Varšava (PL), 21.09.2015-13.09.2015] R&D Projects: GA ČR GA13-34632S Institutional support: RVO:61388998 Keywords : hip joint endoprosthesis * ceramic head * material parameters * weibull's weakest-link theory * sensitivity analysis Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  2. Characterization of a wollastonite glass-ceramic material prepared using sugar cane bagasse ash (SCBA) as one of the raw materials

    International Nuclear Information System (INIS)

    Glass-ceramic material prepared with sugar cane bagasse ash as one of the raw materials was characterized to determine some important properties for its application as a coating material. X-ray diffraction patterns showed that wollastonite-2M (CaSiO3) was the major glass-ceramic phase. The Rietveld method was used to quantify the crystalline (60 wt.%) and vitreous (40 wt.%) phases in the glass-ceramic. The microstructure (determined by scanning electron microscopy) of this material had a marble appearance, showing a microporous network of elongated crystals with some areas with dendritic, feather-like ordering. Microhardness data gave a mean hardness value of 564.4 HV (Vickers-hardness), and light microscopy disclosed a greenish brown colored material with a vitreous luster. - Highlights: • We studied the properties of a glass-ceramic material obtained from sugarcane ash. • This material has the appearance and hardness of natural stones. • A refining method gave information about its amorphous and crystalline phases. • This material has potential to be used as coating plates for buildings

  3. Characterization of a wollastonite glass-ceramic material prepared using sugar cane bagasse ash (SCBA) as one of the raw materials

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Silvio R., E-mail: rainho@fct.unesp.br [Universidade Estadual Paulista — UNESP, Faculdade de Ciências e Tecnologia — FCT, 19060-900 Presidente Prudente — SP (Brazil); Souza, Agda E. [Universidade Estadual Paulista — UNESP, Faculdade de Ciências e Tecnologia — FCT, 19060-900 Presidente Prudente — SP (Brazil); Carvalho, Claudio L.; Reynoso, Victor C.S. [Universidade Estadual Paulista — UNESP, Faculdade de Engenharia de Ilha Solteira — FEIS, 15385-000 Ilha Solteira – SP (Brazil); Romero, Maximina; Rincón, Jesús Ma. [Instituto de Ciencias de la Construccion Eduardo Torroja — IETCC, CSIC, 28033 Madrid (Spain)

    2014-12-15

    Glass-ceramic material prepared with sugar cane bagasse ash as one of the raw materials was characterized to determine some important properties for its application as a coating material. X-ray diffraction patterns showed that wollastonite-2M (CaSiO{sub 3}) was the major glass-ceramic phase. The Rietveld method was used to quantify the crystalline (60 wt.%) and vitreous (40 wt.%) phases in the glass-ceramic. The microstructure (determined by scanning electron microscopy) of this material had a marble appearance, showing a microporous network of elongated crystals with some areas with dendritic, feather-like ordering. Microhardness data gave a mean hardness value of 564.4 HV (Vickers-hardness), and light microscopy disclosed a greenish brown colored material with a vitreous luster. - Highlights: • We studied the properties of a glass-ceramic material obtained from sugarcane ash. • This material has the appearance and hardness of natural stones. • A refining method gave information about its amorphous and crystalline phases. • This material has potential to be used as coating plates for buildings.

  4. Dental ceramics: An update

    Directory of Open Access Journals (Sweden)

    Shenoy Arvind

    2010-01-01

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

  5. Radioactivity in raw materials and end products in the Italian ceramics industry

    International Nuclear Information System (INIS)

    The natural radioactivity due to the presence of 238U, 232Th and 40K in zirconium minerals (zircon and baddeleyite) used in the Italian ceramics industry, in tiles and in waste sludges resulting from ceramic processes, has been measured. The measurements were made by γ-ray spectrometry with a high-purity germanium (HPGe) detector connected to a multichannel analyser. The average concentrations of 238U and 232Th observed in the mineral samples (>3000 and >500 Bq kg-1, respectively) are higher than the concentrations found in the earth's crust by one or two orders of magnitude. The specific activities of tiles and sludges are much lower than in zirconium minerals. The 238U and 232Th concentrations in tiles (50-79 and 52-66 Bq kg-1, respectively) are not higher than in other building materials. The 238U concentration of sludges (116-193 Bq kg-1) is 4-6 times higher than the mean value for the earth's crust. The results are examined on the basis of the existing Italian legislation (D.Lgs no. 230, 1995, Gazzetta Ufficiale 13/06/1996, no. 136, Supplemento Ordinario, Rome, Italy) and the EC Directive no. 29/Euratom of the year 1996 (Gazzetta Ufficiale della Communita Europea 29/06/1996, no. L159)

  6. Industrial ceramics - Properties, forming and applications

    International Nuclear Information System (INIS)

    After a general introduction to ceramics (definition, general properties, elaboration, applications, market data), this book address conventional ceramics (elaboration, material types), thermo-structural ceramics (oxide based ceramics, non-oxide ceramics, fields of application, functional coatings), refractory ceramics, long fibre and ceramic matrix composites, carbonaceous materials, ceramics used for filtration, catalysis and the environment, ceramics for biomedical applications, ceramics for electronics and electrical engineering (for capacitors, magnetic, piezoelectric, dielectric ceramics, ceramics for hyper-frequency resonators), electrochemical ceramics, transparent ceramics (forming and sintering), glasses, mineral binders. The last chapter addresses ceramics used in the nuclear energy sector: in nuclear fuels and fissile material, absorbing ceramics and shields, in the management of nuclear wastes, new ceramics for reactors under construction or for future nuclear energy

  7. LS&T and CMS FY 2004 Feasibility Proposal 04-FS-006 - Ceramic Laser Materials Interim Report - June 8, 2004

    Energy Technology Data Exchange (ETDEWEB)

    Soules, T; Clapsaddle, B; Schaffers, K; Landingham, R

    2005-02-03

    The purpose of this memo is to give an update on our work on ceramic laser materials--feasibility proposal 04-FS-006. Transparent ceramic materials have several major advantages over single crystals in laser applications including, ease and robustness of manufacturing, large apertures, design flexibility, fracture toughness, high activator concentrations, uniformity of composition, no residual stress, and others discussed in the proposal. After a decade of working on making transparent YAG:Nd in 1995 Japanese workers demonstrated samples for the first time that performed as well in lasers 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. The highlights and executive summary of our work to date are: (1) Ordered a slab of transparent YAG:Nd from Konoshima Chemical Co. for evaluation in the SSHCL. Konoshima is the only company in the world currently making ceramic laser materials for sale. Our slab, the largest one made to date, will arrive within a week and will be evaluated in the SSHCL. (2) Met with the inventor of the Konoshima laser ceramic, Dr. Takagimi Yanagitani, and discussed synthesis and performance of these materials in an all day session at LLNL on May 17. (3) Made our first LLNL in-house nano-sized yttrium aluminum garnet by the CMS sol-gel process. (4) Successfully sintering several samples of nano-particle YAG to near translucency. In this report we will discuss each of the above items and include where relevant pictures or tables or references. In addition to reporting interim results this memo will serve as a reference and a place to put relevant data from subsequent samples throughout the study.

  8. Analogies between the mechanical and dielectric properties in the ceramic material type oxide

    Energy Technology Data Exchange (ETDEWEB)

    Boukheit, N. [Laboratoire de Thermodynamique et Traitements de Surface des Materiaux, Departement de Physique, Universite de Constantine, 25000 Constantine (Algeria)], E-mail: boukheit@yahoo.fr; Karaali, A. [Laboratoire de Thermodynamique et Traitements de Surface des Materiaux, Departement de Physique, Universite de Constantine, 25000 Constantine (Algeria); Touil, A.; Mirouh, K. [Laboratoire des Couches Minces et Interfaces, Departement de Physique, Universite de Constantine, 25000 Constantine (Algeria); Treheux, D. [Departement Sciences et Techniques, Ecole Centrale de Lyon, 69131 Ecully cedex (France)

    2009-02-25

    It is well-known that one of the principal difficulties which limit the development of ceramics is their intrinsically brittle nature. In this work we were interested to the study of the single crystal alumina tenacity measured by the Vickers indentation technique in the aim to highlight certain factors responsible for this brittleness. After having defined a reliable protocol of measurement on pure sapphire, we studied the effect on tenacity of the structural defects introduced into the same single crystal by friction and by both X-rays and UV irradiations. The obtained results reveal the importance of these defects which behave, in this case, like trapping sites of electric charges and affect in an important way tenacity of material.

  9. Spectrographic determination of impurities in ceramic materials for nuclear fusion reactors III. Analysis of magnesium oxide

    International Nuclear Information System (INIS)

    The determination of minor and trace elements in the magnesium oxide, considered as possible ceramic material in thermonuclear fusion reactors, has been studied. The concentration ranges are 0.1 - 0.3% for Ca, Si and Y, and at the ppm level for Al, Co, Cr, Fe, Hf, K, Li, Mn, Na, Ni, Se, Ti, V and Zr. Atomic emission spectroscopy with direct current are excitation and photographic detection has been employed. In order to eliminate the effect due to the differences in density between standards and samples, which are a source of errors, a chemical treatment of both is carried out. Likewise, for attaining conditions more suitable for the volatilization of certain impurities, these are determined with the sample in fluoride form. (Author) 11 refs

  10. Spectrographic Determination of Impurities in Ceramic Materials for Nuclear Fusion Reactors. I. Analysis of Alumina

    International Nuclear Information System (INIS)

    The determination of minor and trace elements in the aluminium oxide considered as possible ceramic material in thermonuclear fusion reactors has been studied. The concentration ranges are 0.1 - 0.3 * for Ca, Si and Y, and at the ppm level for Co, Cr, Fe, Hf, K, Li, Mg, Mn, Na, Ni, Se, Ta, Ti, V and Zr. Atomic emission spectroscopy with direct current ore excitation and photographic detection has been employed. For Hf, Mg, Ta, Ti, V and Zr the use of 40% of copper fluoride as a carrier and of Nb as lnternal standard provide suitable sensitivities and precessions, while for the rest of elements the bent results are obtained with graphite powder in different proportions and Rb or Sn as internal standard. (Author) 7 refs

  11. Tauro: a ceramic composite structural material self-cooled Pb-17Li breeder blanket concept

    International Nuclear Information System (INIS)

    The use of a low-activation (LA) ceramic composite (CC) as structural material appears essential to demonstrate the potential of fusion power reactors for being inherently or, at least, passively safe. Tauro is a self-cooled Pb-17Li breeder blanket with a SiC/SiC composite as structure. This study determines the required improvements for existing industrial LA composites (mainly SiC/SiC) in order to render them acceptable for blanket operating conditions. 3D SiC/SiC CC, recently launched on the market, is a promising candidate. A preliminary evaluation of a possible joining technique for SiC/SiC is also described. (orig.)

  12. Development of Hi-Tech ceramics fabrication technologies - Development of advanced nuclear materials

    International Nuclear Information System (INIS)

    The objective of the present work is to prepare the foundation of hi-tech ceramics fabrication technologies through developing important processes i.e., tape casting, sol-gel, single crystal growing, compacting and sintering, and grinding and machining processes. Tape casting process is essential to manufacture hard and functional thin plates and structural elements for some composite materials. For the fabrication of spherical mono-sized micropowders of oxides, sol-gel process has widely been used. Piezoelectric elements that are the core parts of the sensors of LPMS (loose part monitoring system) and ALMS (acoustic leakage monitoring system) are used in single crystal forms. Compacting and sintering processes are general methods for fabricating structural parts using powders. Grinding and machining processes are important to achieve the final dimensions and surface properties of the parts. (Author).

  13. Spectrographic determination of impurities in ceramic materials for nuclear fusion reactors. 1. Analysis of alumina

    International Nuclear Information System (INIS)

    The determination of minor and trace elements in the aluminium oxide considered as possible ceramic material in thermonuclear fusion reactors has been studied. The concentration ranges are 0.1-0.3 % for Ca, Si and Y, and at the ppm level for Co, Cr, Fe, Hf, K, Li, Mg, Mn, Na, Ni, Sc, Ta, Ti, V and Zr. Atomic emission spectroscopy with direct current arc excitation and photographic detection has been employed. For Hf, Mg, Ta, Ti, V and Zr the use of 40% of copper fluoride as a carrier and of Nb as internal standard provide suitable sensitivities and precissions, while for the rest of elements the best results are obtained with graphite powder in different proportions and Rb or Sn as internal standard. (Author). 7 refs

  14. Spectrographic determination of impurities in ceramic materials for nuclear fusion reactors III. Analysis of magnesium oxide

    International Nuclear Information System (INIS)

    The determination of minor and trace elements in the magnesium oxide, considered as possible ceramic material in thermonuclear fusion reactors, has been studied. The concentration ranges are 0.1 - 0.3 % for Ca, Si and Y, and at the ppm level for Al, Co, Cr, Fe, Hf, K, Li, Mn, Na, Ni, Sc, Ti, V and Zr. Atomic emission spectroscopy with direct current arc excitation and photographic detection has been employed. In order to eliminated the effect due to the differences in density between standards and samples, which are a source of errors, a chemical treatment of both is carried out. Likewise, for attaining conditions more suitable for the volatilization of certain impurities, these are determined with the sample in fluoride form. (author)

  15. A compact square loop patch antenna on high dielectric ceramic-PTFE composite material

    Science.gov (United States)

    Ullah, M. Habib; Islam, M. T.

    2013-10-01

    Design and prototyping of a low profile, compact square loop microstrip line fed miniature patch antenna on 1.9 mm thick ceramic-polytetrafluoroethylene (PTFE) high dielectric composite material substrate is presented in this paper. The measured -10 dB return loss bandwidths of the antenna are 300 MHz (0.75-1.05 GHz) and 800 MHz (2.4-3.2 GHz) with 3.4 dBi, 8.86 dBi and 7.42 dBi at 900 MHz, 2.5 GHz and 3.0 GHz, respectively. The measured symmetric and almost stable radiation pattern makes the proposed antenna suitable for RFID, GSM, ZIGBEE, WBAN, LR-WPAN etc. integrated mobile devices.

  16. Growth and instability of charged dislocation loops under irradiation in ceramic materials

    CERN Document Server

    Ryazanov, A I; Kinoshita, C; Klaptsov, A V

    2002-01-01

    We have investigated the physical mechanisms of the growth and stability of charged dislocation loops in ceramic materials with very strong different mass of atoms (stabilized cubic zirconia) under different energies and types of irradiation conditions: 100-1000 keV electrons, 100 keV He sup + and 300 keV O sup + ions. The anomalous formation of extended defect clusters (charged dislocation loops) has been observed by TEM under electron irradiation subsequent to ion irradiation. It is demonstrated that very strong strain field (contrast) near charged dislocation loops is formed. The dislocation loops grow up to a critical size and after then become unstable. The instability of the charged dislocation loop leads to the multiplication of dislocation loops and the formation of dislocation network near the charged dislocation loops. A theoretical model is suggested for the explanation of the growth and stability of the charged dislocation loop, taking the charge state of point defects. The calculated distribution...

  17. Thermoluminescence dating (TL-dating): measurement and accuracy factors in archaeological dating of ceramic base materials

    International Nuclear Information System (INIS)

    Thermoluminescence dating is one of the known techniques that have been established in many laboratories across the region. This technique is capable of dating the archaeological ceramic base materials and provide an absolute measurement with an accuracy of ±15%. The study involves the dating of pottery from a historical site at Sungai Mas, Mukim Kota, Daerah Kuala Muda, Kedah. Pieces of broken pottery of archaeological sample excavated by the Museum Department and Antiquity (JMA) have been dated using the thermoluminescence detector (TLD) techniques at MINT laboratory. A TLD dosemeter of LiF chips is used for the measurement of background and sample dose measurement. The preparation of sample and the calibration techniques for the estimation of palaedose or dose presented in the sample since distant past is established. Results indicate that the samples are in the era of civilization from 200 BP to 1600 BP. Error factors associated in the measurement procedures were identified and discussed. (Author)

  18. Nondestructive evaluation of ceramic and metal matrix composites for NASA's HITEMP and enabling propulsion materials programs

    Science.gov (United States)

    Generazio, Edward R.

    1992-01-01

    In a preliminary study, ultrasonic, x-ray opaque, and fluorescent dye penetrants techniques were used to evaluate and characterize ceramic and metal matrix composites. Techniques are highlighted for identifying porosity, fiber alignment, fiber uniformity, matrix cracks, fiber fractures, unbonds or disbonds between laminae, and fiber-to-matrix bond variations. The nondestructive evaluations (NDE) were performed during processing and after thermomechanical testing. Specific examples are given for Si3N4/SiC (SCS-6 fiber), FeCrAlY/Al2O3 fibers, Ti-15-3/SiC (SCS-6 fiber) materials, and Si3N4/SiC (SCS-6 fiber) actively cooled panel components. Results of this study indicate that the choice of the NDE tools to be used can be optimized to yield a faithful and accurate evaluation of advanced composites.

  19. Fine structure analysis of biocompatible ceramic materials based hydroxyapatite and metallic biomaterials 316L

    International Nuclear Information System (INIS)

    The aim of this paper was to obtain and characterize (surface morphology and fine structure) two types of materials: Ca10(PO4)6(OH)2 hydroxyapatite powder (HAp) as biocompatible ceramic materials and AISI 316L austenitic stainless steels as metallic biomaterials, which are the components of the metal–ceramic composites used for medical implants in reconstructive surgery and prosthetic treatment. The HAp was synthesized by coprecipitation method, heat treated at 200 °C, 800 °C and 1200 °C for 4 h, analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The stainless steel 316L type was made by casting, annealing and machined with a low speed (100 mm/s) in order to obtain a smooth surface and after that has been studied from residual stresses point of view in three polishing regimes conditions: at low speed polishing (150 rpm), at high speed polishing (1500 rpm) and high speed-vibration contact polishing (1500 rpm) using wide angle X-ray diffractions (WAXD). The chemical compositions of AISI 316 steel samples were measured using a Foundry Master Spectrometer equipped with CCD detector for spectral lines and the sparking spots of AISI 316L samples were analyzed using SEM. By XRD the phases of HAp powders have been identified and also the degree of crystallinity and average size of crystallites, and with SEM, we studied the morphology of the HAp. It has been found from XRD analysis that we obtained HAp with a high degree of crystallinity at 800 °C and 1200 °C, no presence of impurity and from SEM analysis we noticed the influence of heat treatment on the ceramic particles morphology. From the study of residual stress profiles of 316L samples were observed that it differs substantially for different machining regimes and from the SEM analysis of sparking spots we revealed the rough surfaces of stainless steel rods necessary for a better adhesion of HAp on it.

  20. Contact resistance of ceramic interfaces between materials used for solid oxide fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Koch, S.

    2002-01-01

    The contact resistance can be divided into two main contributions. The small area of contact between ceramic components results in resistance due to current constriction. Resistive phases or potential barriers at the interface result in an interface contribution to the contact resistance, which may be smaller or larger than the constriction resistance. The contact resistance between pairs of three different materials were analysed (strontium doped lanthanum manganite, yttria stabilised zirconia and strontium and nickel doped lanthanum cobaltite), and the effects of temperature, atmosphere, polarisation and mechanical load on the contact resistance were investigated. The investigations revealed that the mechanical load of a ceramic contact has a high influence on the contact resistance, and generally power law dependence between the contact resistance and the mechanical load was found. The influence of the mechanical load on the contact resistance was ascribed to an area effect. The contact resistance of the investigated materials was dominated by current constriction at high temperatures. The measured contact resistance was comparable to the resistance calculated on basis of the contact areas found by optical and electron microscopy. At low temperatures, the interface contribution to the contact resistance was dominating. The cobaltite interface could be described by one potential barrier at the contact interface, whereas the manganite interfaces required several consecutive potential barriers to model the observed behaviour. The current-voltage behaviour of the YSZ contact interfaces was only weakly non-linear, and could be described by 22{+-}1 barriers in series. Contact interfaces with sinterable contact layers were also investigated, and the measured contact resistance for these interfaces were more than 10 times less than for the other interfaces. (au)

  1. Influence of impurities in raw materials on zirconia-toughened mullite ceramics removed by B/sub 2/O/sub 3/

    International Nuclear Information System (INIS)

    Mechanical properties and microstructure of a zirconia toughened mullite ceramics (ZTM ceramics) prepared by using an electrically fused mullite as a raw material were studied in the present work. It was found that the raw material contained more alkali-metal ions, such as a sodium ion (Na+) and a potassium ion (K+), which were proven to be the dominant factor for deteriorating the ceramic properties. The impurities in the raw material have led to the decrease of the mechanical properties. The impurities in the raw materials have led to the decrease of the mechanical properties of ZTM ceramics by changing properties (for example, viscosity) of a glassy phase in the ceramics, especially at high temperature. In this work the mechanical properties of the ceramics were improved by adding B/sub 2/O/sub 3/ additive and its toughness at room temperature increased from 4.4 MPa under the roote m to 5.9 MPa under the roote m and that at 800 deg. C from 2.9 MPa under the roote m to 4.4 MPa under the roote m. The toughness of the ceramic at room temperature was 34% increased and that ceramics and the improvement of the ceramic properties by B/sub 2/O/sub 3/ additive were studied and their mechanisms discussed. (author)

  2. Bibliography of the technical literature of the Materials Joining Group, Metals and Ceramics Division, 1951 through June 1987

    International Nuclear Information System (INIS)

    This document contains a listing of the written scientific information originating in the Materials Joining Group (formerly the Welding and Brazing Group), Metals and Ceramics Division, Oak Ridge National Laboratory during 1951 through June 1987. It is a registry of about 400 documents as nearly as possible in the order in which they were issued

  3. Ceramic Methyltrioxorhenium

    CERN Document Server

    Herrmann, R; Eickerling, G; Helbig, C; Hauf, C; Miller, R; Mayr, F; Krug von Nidda, H A; Scheidt, E W; Scherer, W; Herrmann, Rudolf; Troester, Klaus; Eickerling, Georg; Helbig, Christian; Hauf, Christoph; Miller, Robert; Mayr, Franz; Nidda, Hans-Albrecht Krug von; Scheidt, Ernst-Wilhelm; Scherer, Wolfgang

    2006-01-01

    The metal oxide polymeric methyltrioxorhenium [(CH3)xReO3] is an unique epresentative of a layered inherent conducting organometallic polymer which adopts the structural motifs of classical perovskites in two dimensions (2D) in form of methyl-deficient, corner-sharing ReO5(CH3) octahedra. In order to improve the characteristics of polymeric methyltrioxorhenium with respect to its physical properties and potential usage as an inherentconducting polymer we tried to optimise the synthetic routes of polymeric modifications of 1 to obtain a sintered ceramic material, denoted ceramic MTO. Ceramic MTO formed in a solvent-free synthesis via auto-polymerisation and subsequent sintering processing displays clearly different mechanical and physical properties from polymeric MTO synthesised in aqueous solution. Ceramic MTO is shown to display activated Re-C and Re=O bonds relative to MTO. These electronic and structural characteristics of ceramic MTO are also reflected by a different chemical reactivity compared with its...

  4. Engineering ceramics

    CERN Document Server

    Bengisu, Murat

    2001-01-01

    This is a comprehensive book applying especially to junior and senior engineering students pursuing Materials Science/ Engineering, Ceramic Engineering and Mechanical Engineering degrees. It is also a reference book for other disciplines such as Chemical Engineering, Biomedical Engineering, Nuclear Engineering and Environmental Engineering. Important properties of most engineering ceramics are given in detailed tables. Many current and possible applications of engineering ceramics are described, which can be used as a guide for materials selection and for potential future research. While covering all relevant information regarding raw materials, processing properties, characterization and applications of engineering ceramics, the book also summarizes most recent innovations and developments in this field as a result of extensive literature search.

  5. In-waveguide measurements of MMW dielectric properties of ceramic materials for the US fusion reactor materials research program

    International Nuclear Information System (INIS)

    The objective is to obtain accurate measurements of dielectric properties of candidate ceramic insulating materials for fusion reactors. As part of an IEA collaboration, a set of round-robin materials was purchased for comparing dielectric measurements at laboratories in the United Kingdom, Spain, Germany, US, and Japan. P. Pells at Aldermasten, UK, purchased MACOR 9658, a glass-mica composite, and Roger Stoller, from ORNL, purchased WESGO AL-300 and AL-995, polycrystalline alumina standards. The authors obtained some of each of these materials for making these measurements. The results have been shared with the other IEA partners, and P. Pells is preparing a summary document. They used the millimeter wave apparatus described below and elsewhere in detail to measure the dielectric properties of these materials at 90 to 100 Ghz at room temperature. The nominal purity of AL-300 was 0.967; the nominal purity of AL-995 was 0.995. Their method was to measure the power transmission coefficient. They used computerized data reduction techniques to compute k (the dielectric constant) and tanδ (the loss tangent) directly from transmission maxima and their corresponding frequencies; to verify this method, they applied the same technique to theoretically derived channel spectra that were obtained by solving exactly the complex transmission coefficient, given k and tanδ. The alumina material with a lower level of purity resulted in higher loss but lower dielectric constant. They obtained dielectric constants that were higher for all the materials than manufacturer-reported values taken at lower frequencies. In addition, they obtained higher dielectric constant values than those found by other investigators at 100 GHz for AL-995 and MACOR. Tanδ values were in good agreement with those of other investigators obtained by free-space methods and dispersive Fourier-transform techniques in the same frequency range

  6. Method for improving the performance of oxidizable ceramic materials in oxidizing environments

    Science.gov (United States)

    Nagaraj, Bangalore A. (Inventor)

    2002-01-01

    Improved adhesion of thermal barrier coatings to nonmetallic substrates using a dense layer of ceramic on an underlying nonmetallic substrate that includes at least one oxidizable component. The improved adhesion occurs because the application of the dense ceramic layer forms a diffusion barrier for oxygen. This diffusion barrier prevents the oxidizable component of the substrate from decomposing. The present invention applies ceramic by a process that deposits a relatively thick and dense ceramic layer on the underlying substrate. The formation of the dense layer of ceramic avoids the problem of void formation associated with ceramic formation by most prior art thermal decomposition processes. The formation of voids has been associated with premature spalling of thermal barrier layers and other protective layers applied to substrates.

  7. Probing mechanical properties of thin film and ceramic materials in micro- and nano-scale using indentation techniques

    International Nuclear Information System (INIS)

    In this study, we report on the mechanical properties, failure and fracture modes in two cases of engineering materials; that is transparent silicon oxide thin films onto poly(ethylene terephthalate) (PET) membranes and glass-ceramic materials. The first system was studied by the quazi-static indentation technique at the nano-scale and the second by the static indentation technique at the micro-scale. Nanocomposite laminates of silicon oxide thin films onto PET were found to sustain higher scratch induced stresses and were effective as protective coating material for PET membranes. Glass-ceramic materials with separated crystallites of different morphologies sustained a mixed crack propagation pattern in brittle fracture mode.

  8. Probing mechanical properties of thin film and ceramic materials in micro- and nano-scale using indentation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Charitidis, Costas A., E-mail: charitidis@chemeng.ntua.gr [National Technical University of Athens, School of Chemical Engineering, 9 Heroon Polytechniou St., Zographos, Athens GR-157 80 (Greece)

    2010-10-01

    In this study, we report on the mechanical properties, failure and fracture modes in two cases of engineering materials; that is transparent silicon oxide thin films onto poly(ethylene terephthalate) (PET) membranes and glass-ceramic materials. The first system was studied by the quazi-static indentation technique at the nano-scale and the second by the static indentation technique at the micro-scale. Nanocomposite laminates of silicon oxide thin films onto PET were found to sustain higher scratch induced stresses and were effective as protective coating material for PET membranes. Glass-ceramic materials with separated crystallites of different morphologies sustained a mixed crack propagation pattern in brittle fracture mode.

  9. Technical evaluation panel summary report. Ceramic and glass immobilization options fissile materials disposition program

    Energy Technology Data Exchange (ETDEWEB)

    Myers, B. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brummond, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Armantrout, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shaw, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jantzen, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jostons, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McKibben, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Strachan, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vienna, J. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    1997-12-23

    This report documents the results of a technical evaluation of the merits of ceramic and glass immobilization forms for the disposition of surplus weapons-useable plutonium. The evaluation was conducted by a Technical Evaluation Panel (TEP), whose members were selected to cover a relevant range of scientific and technical expertise and represented each of the technical organizations involved in the Plutonium Immobilization Program. The TEP held a formal review at Lawrence Liver-more National Laboratory (LLNL) from July 2%August 1, 1997. Following this review, the TEP documented the review and its evaluation of the two immobilization technologies in this report to provide a technical basis for a recommendation by LLNL to the Department of Energy (DOE) for the preferred immobilization form. The comparison of the glass and ceramic forms and manufacturing processes was a tremendous challenge to the TEP. The two forms and their processes are similar in many ways. The TEP went to great effort to accurately assess what were, in many cases, fine details of the processes, unit operations, and the glass and ceramic forms themselves. The set of criteria used by the Fissile Materials Disposition Program (FMDP) in past screenings and down-selections was used to measure-the two options. One exception is that the TEP did not consider criteria that were largely nontechnical (namely international impact, public acceptance, and effects on other : DOE programs). The TEP' s measures and assessments are documented in detail. Care was taken to ensure that the data used were well documented and traceable to their source. Although no final conclusion regarding the preferred form was reached or explicitly stated in this report (this was not within the TEP' s charter), no "show stoppers" were identified for either form. Both forms appear capable of satisfying all the criteria, as interpreted by the TEP. The TEP identified a number of distinct and quantifiable differences between

  10. Technical evaluation panel summary report: ceramic and glass immobilization options fissile materials disposition program

    International Nuclear Information System (INIS)

    This report documents the results of a technical evaluation of the merits of ceramic and glass immobilization forms for the disposition of surplus weapons-useable plutonium. The evaluation was conducted by a Technical Evaluation Panel (TEP), whose members were selected to cover a relevant range of scientific and technical expertise and represented each of the technical organizations involved in the Plutonium Immobilization Program. The TEP held a formal review at Lawrence Liver-more National Laboratory (LLNL) from July 2%August 1, 1997. Following this review, the TEP documented the review and its evaluation of the two immobilization technologies in this report to provide a technical basis for a recommendation by LLNL to the Department of Energy (DOE) for the preferred immobilization form. The comparison of the glass and ceramic forms and manufacturing processes was a tremendous challenge to the TEP. The two forms and their processes are similar in many ways. The TEP went to great effort to accurately assess what were, in many cases, fine details of the processes, unit operations, and the glass and ceramic forms themselves. The set of criteria used by the Fissile Materials Disposition Program (FMDP) in past screenings and down-selections was used to measure-the two options. One exception is that the TEP did not consider criteria that were largely nontechnical (namely international impact, public acceptance, and effects on other : DOE programs). The TEP s measures and assessments are documented in detail. Care was taken to ensure that the data used were well documented and traceable to their source. Although no final conclusion regarding the preferred form was reached or explicitly stated in this report (this was not within the TEP s charter), no show stoppers were identified for either form. Both forms appear capable of satisfying all the criteria, as interpreted by the TEP. The TEP identified a number of distinct and quantifiable differences between the forms for

  11. 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.

  12. Novel Low Temperature Co-Fired Ceramic Material System Composed of Dielectrics with Different Dielectric Constants

    Science.gov (United States)

    Sakamoto, Sadaaki; Adachi, Hiroshige; Kaneko, Kazuhiro; Sugimoto, Yasutaka; Takada, Takahiro

    2013-09-01

    We found that the co-firing low temperature co-fired ceramic (LTCC) materials of different dielectric constants (ɛr) with Cu wiring is achievable using a novel, original design. It was confirmed that the dielectric characteristics of the dielectrics designed in this study are very suitable for the use of the dielectrics in electronic components such as filters mounted in high-speed radio communication equipment. The dielectric constants of the lower- and higher-dielectric-coefficient materials were 8.1 and 44.5, respectively, which are sufficiently effective for downsizing LTCC components. Observing the co-fired interface, it was confirmed that excellent co-firing conditions resulted in no mechanical defects such as delamination or cracks. On the basis of the results of wavelength dispersive X-ray spectrometry (WDX) and X-ray diffractometry (XRD), it was confirmed that co-firing with minimal interdiffusion was realized using the same glass for both dielectrics. It is concluded that the materials developed are good for co-firing in terms of the mechanical defects and interdiffusion that appear in them.

  13. 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)

  14. Determination of the raw material source used in the production of ceramics of the Hatahara archaeological site, AM, Brazil

    International Nuclear Information System (INIS)

    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)

  15. Small-angle scattering in materials science - a short review of applications in alloys, ceramics and composite materials

    International Nuclear Information System (INIS)

    Since the early days of small-angle scattering (SAS), this technique has been used to characterize the structure of solid materials on the nanometer scale. Some recent developments in this field will be reviewed, focusing on alloys, ceramics and (nano-) composite materials. The large field of SAS from polymeric systems will not be covered. Classical applications of SAS are the characterization of pores or precipitates in alloys, for instance. In more recent years, a range of new applications for X-ray SAS has emerged owing to the availability of more and more brilliant (synchrotron) X-ray sources. Examples include grazing-incidence SAXS, used increasingly to characterize nano-structured surfaces on semiconductors and also on other materials. The use of a narrow X-ray beam also allows the investigation of extremely inhomogeneous or hierarchically structured materials by scanning SAXS. In this approach, the specimen is moved step by step across an X-ray beam with a diameter of a few micrometers (or even less), collecting a SAXS pattern at each step. In neutron SAS, the systematic use of magnetic cross-sections has brought considerable progress in the study of magnetic nano-particles or nano-composites. Single crystalline or textured materials are being studied under several orientations with respect to the primary beam to yield three-dimensional (neutron or X-ray) SAS patterns. In many cases, SAS is combined with other techniques, such as electron microscopy, spectroscopy or mechanical characterization, the most elegant being an in-situ combination. A number of recent examples for the above-mentioned approaches will be given. (orig.)

  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=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 coupling agent can dramatically reduce the average lifetime of dental composites.

  17. High temperature resistant materials and structural ceramics for use in high temperature gas cooled reactors and fusion plants

    International Nuclear Information System (INIS)

    Irrespective of the systems and the status of the nuclear reactor development lines, the availability, qualification and development of materials are crucial. This paper concentrates on the requirements and the status of development of high temperature metallic and ceramic materials for core and heat transferring components in advanced HTR supplying process heat and for plasma exposed, high heat flux components in Tokamak fusion reactor types. (J.P.N.)

  18. The economic geology of clays/shales raw materials for the ceramics industry in Lebanon

    International Nuclear Information System (INIS)

    Author.Field, laboratory and market studies are a must for proper evaluation of natural resources for the mineral industry of lebanon. Sites selectively convenient to the existing major Lebanese ceramics industry centered in the Beqa'a region, were investigated as to their geology, geography and economic character. The raw materials are shales, mud stones, siltstones and other argillaceous rocks of Jurassic to Cretaceous age coming from selective sites in south and central Lebanon. The finished products include wall, floor, roofing tiles, pipes, sanitary ware, pottery and brick specimens. Differential thermal analysis, scanning electron microscopy, firing and physico-chemical tests and analyses characterized the raw materials into two major groups: the suitable are siliceous argillaceous rocks and unsuitable calcareous argillaceous rocks. The suitable group is divided into two varieties. The first is dominantly a disordered Kaolinite with low drying and firing values, low plasticity index, giving a gray firing color, and with low iron and soluble salts content. The second is dominantly illite with the above properties showing medium values, and giving a red color due to the iron content. The unsuitable group is dominantly an intermixed clay type with high plasticity, soluble salts content and shrinkage values. The exposed parts, of the studied 11 sites the proved suitable, have estimated reserves around 23000 m3. This is only a fraction of the resources available to meet industrial consumption requirements. Further area coverage investigation and drilling would prove the very high potential existing for the industry. These Lebanese materials as determined by their properties, are used partially or fully in the various products. The foreign import, notably from non-Arab sources can be substituted by nearby economic Arab deposits. The ceramics industry is faced with developmental problems, economic, social and technical. Securing the local and the surrounding market

  19. 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)

  20. The production of ceramic materials in Roman Pavia. An archaeometric NAA investigation of clay sources and archaeological artifacts

    International Nuclear Information System (INIS)

    Part of a research program on cultural heritage aimed to elucidate the production of ceramic artifacts in Roman Pavia is devoted to the localization of the possible sources of raw materials (claypits) as well as to the technological production processes. Clay samples were collected in two different areas nearby Pavia, Lomellina and Oltrepo. Some of these samples were also fired at 950 deg C. Archaeological ceramic samples, mostly bricks and tiles of Roman age, were obtained from excavations of Roman settings close to Pavia. All samples were submitted to instrumental neutron activation analysis for the determination of Ca, Fe and a number of trace elements. Results indicate (1) fired and raw clay samples keep the same elemental fingerprint so that only raw samples data can be used in archaeometric studies; (2) some parameters based on rare earth elements are useful to discriminate the clay samples from the two investigated areas; (3) clay discrimination is confirmed also by discriminant analysis; and (4) the insertion of the elemental composition data of the ceramic artifacts in the statistical treatment allows one to assign the artifacts to one of the investigated areas and confirms that, at Roman times, the production of ceramic building materials was mostly based on the use of local prime matter. (author)

  1. The Production and Characterization of Ceramic Carbon Electrode Materials for CuCl-HCl Electrolysis

    Science.gov (United States)

    Edge, Patrick

    Current H2 gas supplies are primarily produced through steam methane reforming and other fossil fuel based processes. This lack of viable large scale and environmentally friendly H2 gas production has hindered the wide spread adoption of H2 fuel cells. A potential solution to this problem is the Cu-Cl hybrid thermochemical cycle. The cycle captures waste heat to drive two thermochemical steps creating CuCl as well as O2 gas and HCl from CuCl2 and water. The CuCl is oxidized in HCl to produce H2 gas and regenerate CuCl2, this process occurs at potentials well below those required for water electrolysis. The electrolysis process occurs in a traditional PEM fuel-cell. In the aqueous anolyte media Cu(I) will form anionic complexes such as CuCl 2 - or CuCl32-. The slow transport of these species to the anode surface limits the overall electrolysis process. To improve this transport process we have produced ceramic carbon electrode (CCE) materials through a sol-gel method incorporating a selection of amine containing silanes with increasing numbers of primary and secondary amines. When protonated these amines allow for improved transport of anionic copper complexes. The electrochemical and physical characterization of these CCE materials in a half and full-cell electrolysis environment will be presented. Electrochemical analysis was performed using cell polarization, cyclic voltammetry, and electrochemical impedance spectroscopy.

  2. Examining the performance of refractive conductive ceramics as plasmonic materials: a theoretical approach

    CERN Document Server

    Kumar, Mukesh; Ishii, Satoshi; Nagao, Tadaaki

    2016-01-01

    The main aim of the study is to scrutinize promising plasmonic materials by understanding and correlating the electronic structure to optical properties of selected refractory materials. For this purpose, the electronic and optical properties of conductive ceramics TiC, ZrC, HfC, TaC, WN, TiN, ZrN, HfN, TaN and WN are studied systematically by means of the first-principles density functional theory. A full ab-initio procedure to calculate plasma frequency from electronic band structure is discussed. The dielectric functions are calculated including both interband and intraband transitions. Our calculations confirmed that transition metal nitrides such as TiN, ZrN and HfN are the strongest candidates close to the performance of conventional noble metals in the visible to the near-infrared regions. On the other hand, carbides are not suitable for plasmonic applications due to very large losses in the same regions. By adopting the dielectric functions calculated from the calculations, the scattering and absorpti...

  3. Material Development and Processing of Multiscale Structured Ceramics for SOFC-Electrodes

    Science.gov (United States)

    Neukam, M.; Pannerselvam, M.; Willert-Porada, M.

    2008-02-01

    NiO-ZrO2-cermets are used as anode material in Solid Oxide Fuel Cells. A sub-structured cermet consisting aligned lamella of NiO and 8Y-ZrO2 is obtained by melt processing of a eutectic powder mixture. Direct co-firing of such cermet powders with the ceramic electrolyte layer requires sintering temperatures above 1600 °C and leads to redistribution of NiO. Sintering with AlN as reactive component for in-situ formation of cubic ZrxOyNz, promotes joining of the sub-structured anode material with the solid electrolyte via the ionic conductive 8Y-ZrO2-grains at 1400-1550 °C. By decomposition of the Zr-oxynitride upon cooling, new porosity and the desired connectivity between the anode and the solid electrolyte is formed. A graded composite is obtained at an interface, which consists of e.g., ZrO2, Zr7O9.5N3, β-ZrAlON, NiAl2O4 and Ni, depending upon the sintering temperature.

  4. Analysis of the influence of process conditions on the surface finish of ceramic materials manufactured by EDM

    International Nuclear Information System (INIS)

    Electrical discharge machining (EDM) is an emerging alternative versus some other manufacturing processes of conductive ceramic materials, such as: laser machining, electrochemical machining, abrasive water jet, ultrasonic machining and diamond wheel grinding. Due to its interest in the industrial field, in this work a study of the influence of process conditions on the surface aspect of three conductive ceramic materials: hot-pressed boron carbide (B4C), reaction-bonded silicon carbide (SiSiC) and cobalt-bonded tungsten carbide (WC-Co) is carried out. These materials are to be electrical discharge machined under different machining conditions and in the particular case of finish stages (Ra≤ 1 μm). (Author)

  5. Estimating the erosion and degradation performance of ceramic and polymeric insulator materials in high current arc environments

    Energy Technology Data Exchange (ETDEWEB)

    Engel, T.G.; Kristiansen, M.; O' Hair, E. (Texas Tech Univ., Lubbock, TX (United States). Dept. of Electrical Engineering); Marx, J.N. (Texas Tech Univ., Lubbock, TX (United States). Dept. of Chemistry and Biochemistry)

    1991-01-01

    This paper reports on the rates of erosion and voltage holdoff degradation which are critical parameters when selecting insulator materials that are used in pulsed power devices such as spark gaps, surface discharge switches, and electromagnetic launchers. This investigation is concerned with modeling the erosion and holdoff degradation performance of various commercially available polymeric and ceramic insulators. The insulators are tested on a surface discharge switch at {approximately}300 kA in atmospheric air. Test diagnostics include the surface voltage holdoff recovery and the eroded mass loss of the insulator and electrode materials used. The ceramic materials which were tested include several types of aluminum and magnesium silicates, several alumina and zirconia composites, and aluminum and silicon nitride. The polymeric insulators include polyvinyl chloride, low and high molecular weight polyethylene, polytetrafluoroethylene, polyamide, acetyl, polyamide-imide, and several types of glass-reinforced epoxies, melamines, and phenolics.

  6. Perspectives of development of ceramic materials with luminescent applications; Perspectivas del desarrollo de materiales ceramicos con aplicaciones luminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado E, A.; Fernandez M, J.L.; Diaz G, J.L.I.; Rivera M, T. [IPN, Av. Legaria 694, 11500 Mexico D.F. (Mexico)

    2005-07-01

    The science and technology of materials believes and it applies the knowledge that allow to relate the composition, it structures and the one processed with those properties that those they make capable for each one of the applications. The ceramic materials are inorganic materials not metallic, constituted by metallic elements and not metallic. In general, they usually behave, as good insulating electric and thermal due to the absence of conductive electrons. Usually, they possess relatively high coalition temperatures and, also, a chemical stability relatively high. Due to these properties, they are indispensable for many of those designs in engineering. The ceramic materials for luminescent applications are constituted typically by pure compounds (Al{sub 2}O{sub 3}, TiO{sub 2}, SiO{sub 2} and ZrO{sub 2}) or cocktails with some sludges giving as a result (Al{sub 2}O{sub 3}:TR, TiO{sub 2}:Eu, Si:ZrO{sub 2}, ZrO{sub 2}:TR). Presently work describes the panorama to big features on the development of ceramic materials in the CICATA Unit it would Bequeath, which can be characterized by the photoluminescence techniques and thermoluminescence mainly. (Author)

  7. Immobilization of actinides in stable mineral type and ceramic materials (high temperature synthesis)

    Energy Technology Data Exchange (ETDEWEB)

    Starkov, O.; Konovalov, E.

    1996-05-01

    Alternative vitrification technologies are being developed in the world for the immobilization of high radioactive waste in materials with improved thermodynamic stability, as well as improved chemical and thermal stability and stability to radiation. Oxides, synthesized in the form of analogs to rock-forming minerals and ceramics, are among those materials that have highly stable properties and are compatible with the environment. In choosing the appropriate material, we need to be guided by its geometric stability, the minimal number of cations in the structure of the material and the presence of structural elements in the mineral that are isomorphs of uranium and thorium, actinoids found in nature. Rare earth elements, yttrium, zirconium and calcium are therefore suitable. The minerals listed in the table (with the exception of the zircon) are pegatites by origin, i.e. they are formed towards the end of the magma crystallization of silicates form the residual melt, enriched with Ta, Nb, Ti, Zr, Ce, Y, U and Th. Uranium and thorium in the form of isomorphic admixtures form part of the lattice of the mineral. These minerals, which are rather simple in composition and structure and are formed under high temperatures, may be viewed as natural physio-chemical systems that are stable and long-lived in natural environments. The similarity of the properties of actinoids and lanthanoids plays an important role in the geochemistry of uranium and thorium; however, uranium (IV) is closer to the {open_quotes}heavy{close_quotes} group of lanthanoids (the yttrium group) while thorium (IV) is closer to the {open_quotes}light{close_quotes} group (the cerium group). That is why rare earth minerals contain uranium and thorium in the form of isomorphic admixtures.

  8. Evaluation of temperature dependence of the emission cross-section of Yb-doped ceramic materials from 298K to 393K for high average power operation

    International Nuclear Information System (INIS)

    The temperature dependence of the emission cross-sections of ceramic materials doped with Yb have been investigated in the temperature range from 298K to 393K. The materials such as YAG, Y2O3 and Lu2O3 have been adopted as host ceramic materials. The emission spectra have been found to decrease with a rise in temperature. The cross sections at the wavelength giving the peaks in the emission spectra have shown a gradual decrease against temperature. (author)

  9. 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

  10. In vitro wear of four ceramic materials and human enamel on enamel antagonist.

    Science.gov (United States)

    Nakashima, Jun; Taira, Yohsuke; Sawase, Takashi

    2016-06-01

    The purpose of the present study was to evaluate the wear of four different ceramics and human enamel. The ceramics used were lithium disilicate glass (e.max Press), leucite-reinforced glass (GN-Ceram), yttria-stabilized zirconia (Aadva Zr), and feldspathic porcelain (Porcelain AAA). Hemispherical styli were fabricated with these ceramics and with tooth enamel. Flattened enamel was used for antagonistic specimens. After 100,000 wear cycles of a two-body wear test, the height and volume losses of the styli and enamel antagonists were determined. The mean and standard deviation for eight specimens were calculated and statistically analyzed using a non-parametric (Steel-Dwass) test (α = 0.05). GN-Ceram exhibited greater stylus height and volume losses than did Porcelain AAA. E.max Press, Porcelain AAA, and enamel styli showed no significant differences, and Aadva Zr exhibited the smallest stylus height and volume losses. The wear of the enamel antagonist was not significantly different among GN-Ceram, e.max Press, Porcelain AAA, and enamel styli. Aadva Zr resulted in significantly lower wear values of the enamel antagonist than did GN-Ceram, Porcelain AAA, and enamel styli. In conclusion, leucite-reinforced glass, lithium disilicate glass, and feldspathic porcelain showed wear values closer to those for human enamel than did yttria-stabilized zirconia. PMID:27059093

  11. Measuring Fracture Times Of Ceramics

    Science.gov (United States)

    Shlichta, Paul J.; Bister, Leo; Bickler, Donald G.

    1989-01-01

    Electrical measurements complement or replace fast cinematography. Electronic system measures microsecond time intervals between impacts of projectiles on ceramic tiles and fracture tiles. Used in research on ceramics and ceramic-based composite materials such as armor. Hardness and low density of ceramics enable them to disintegrate projectiles more efficiently than metals. Projectile approaches ceramic tile specimen. Penetrating foil squares of triggering device activate display and recording instruments. As ceramic and resistive film break oscilloscope plots increase in electrical resistance of film.

  12. Physicochemical study of ceramics from Pre classic of Cuicuilco 'C' Mexico, methodology to define origin of raw material

    International Nuclear Information System (INIS)

    Cuicuilco has been considered one of the most important centers during the Formative Period (1000 - 0 b. C.) in the south of Mexico Basin, mainly, due its dimensions. Because of the Xitle volcano eruption, its occupation decreases around 200 b. C. This paper presents the results of a multidisciplinary investigation about ceramic material from Cuicuilco 'C', located in the south of Mexico City, and sediments from different places near to it. The analysis was done by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X- Ray Diffraction (XRD). Its results show the presence of Si, O, Fe and Al as majority elements, and crystalline phases as albite, hematite, quartz, maghemite and cristobalite. Chemical elements identified at ceramic samples has been submitted to an statistical analysis in order to be compared with the results of analyzed sediments, to determinate the raw material origin. (Author)

  13. Comparison of slime-producing coagulase-negative Staphylococcus colonization rates on vinyl and ceramic tile flooring materials.

    Science.gov (United States)

    Yazgi, H; Uyanik, M H; Ayyildiz, A

    2009-01-01

    This study investigated the colonization of slime-producing coagulase-negative Staphylococcus (CoNS) in 80 patient wards in Turkey (40 vinyl and 40 ceramic tile floors). A total of 480 samples that included 557 CoNS isolates were obtained. Slime production was investigated with the Christensen method and methicillin-susceptibility was tested by the disk-diffusion method. There was a significant difference in the percentage of slime-producing CoNS isolates on vinyl (12.4%) versus ceramic tile flooring (4.4%). From vinyl flooring, the percentage of slime producing methicillin-resistant CoNS (MRCoNS) (8.9%) was significantly higher than for methicillin-sensitive CoNS (MSCoNS) (3.6%), whereas there was no difference from ceramic tile flooring (2.5% MRCoNS versus 1.8% MSCoNS). The most commonly isolated slime-producing CoNS species was S. epidermidis on both types of flooring. It is concluded that vinyl flooring seems to be a more suitable colonization surface for slime-producing CoNS than ceramic tile floors. Further studies are needed to investigate bacterial strains colonized on flooring materials, which are potential pathogens for nosocomial infections. PMID:19589249

  14. Microstructural characterization and influence of manufacturing parameters on technological properties of vitreous ceramic materials

    International Nuclear Information System (INIS)

    Microstructure of vitreous ceramic samples manufactured from kaolinitic-clay and feldspars raw materials from Cameroon was investigated in the range 1150-1250 deg. C by X-ray diffraction and scanning electron microscopy and by measuring some technological properties. Moreover, the simultaneous influence of feldspars content, heating temperature and soaking time on water absorption and firing shrinkage was evaluated by adopting the response surface methodology (Doehlert matrix), using the New Efficient Methodology for Research using Optimal Design (NEMROD) software. The results show that a spinel phase, mullite, glassy phase and some amount of hematite were formed. However, the spinel phase and potassic feldspar, as compared to the sodic one, disappeared at moderate firing temperature and soaking time. Apparently, mullite developed from spinel phase, which is formed from the demixion of metakaolin. On the other hand, it is found that the effects of fluxing content and firing temperature on the measured properties were almost similar and more influent than soaking time. Antagonistic and synergetic interactions existed between the considered parameters, and their importance differed for the considered properties. By using this mathematical tool, suitable operating conditions for manufacturing vitreous bodies were determined.

  15. Analysis of the temperature and stress distributions in ceramic window materials subjected to microwave heating

    International Nuclear Information System (INIS)

    The temperature and stress and distributions generated in ceramic materials currently employed in microwave gyrotron tube windows were determined for a variety of operating conditions. Both edge- and face-cooled windows of either polycrystalline BeO or polycrystalline Al2O3 were considered. The actual analysis involved three steps. First, a computer program was used to determine the electric field distribution within the window at a given power level and frequency (TE02 wave propagation assumed). This program was capable of describing both the radial and axial dependence of the electric field. The effects of multiple internal reflections at the various dielectric interfaces were also accounted for. Secondly, the field distribution was used to derive an expression for the heat generated per unit volume per unit time within the window due to dieletric losses. A generalized heat conduction computer code was then used to compute the temperature distribution based on the heat generation function. Third, the stresses were determined from the temperature profiles using analytical expression or a finite-element computer program. Steady-state temperature and stress profiles were computed for the face-cooled and edge-cooled windows

  16. Microstructural characterization and influence of manufacturing parameters on technological properties of vitreous ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Njoya, D. [Laboratoire de Physico-chimie des Materiaux Mineraux, Departement de Chimie Inorganique, Faculte des Sciences, Universite de Yaounde I, B.P. 812, Yaounde (Cameroon); Laboratoire de Physico-chimie des Materiaux et Environnement, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Hajjaji, M., E-mail: Hajjaji@ucam.ac.ma [Laboratoire de Physico-chimie des Materiaux et Environnement, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Bacaoui, A. [Laboratoire de Chimie Organique Appliquee, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Njopwouo, D. [Laboratoire de Physico-chimie des Materiaux Mineraux, Departement de Chimie Inorganique, Faculte des Sciences, Universite de Yaounde I, B.P. 812, Yaounde (Cameroon)

    2010-03-15

    Microstructure of vitreous ceramic samples manufactured from kaolinitic-clay and feldspars raw materials from Cameroon was investigated in the range 1150-1250 deg. C by X-ray diffraction and scanning electron microscopy and by measuring some technological properties. Moreover, the simultaneous influence of feldspars content, heating temperature and soaking time on water absorption and firing shrinkage was evaluated by adopting the response surface methodology (Doehlert matrix), using the New Efficient Methodology for Research using Optimal Design (NEMROD) software. The results show that a spinel phase, mullite, glassy phase and some amount of hematite were formed. However, the spinel phase and potassic feldspar, as compared to the sodic one, disappeared at moderate firing temperature and soaking time. Apparently, mullite developed from spinel phase, which is formed from the demixion of metakaolin. On the other hand, it is found that the effects of fluxing content and firing temperature on the measured properties were almost similar and more influent than soaking time. Antagonistic and synergetic interactions existed between the considered parameters, and their importance differed for the considered properties. By using this mathematical tool, suitable operating conditions for manufacturing vitreous bodies were determined.

  17. Thermal Conductivity and Water Vapor Stability of HfO2-based Ceramic Coating Materials

    Science.gov (United States)

    Zhu, Dongming; Fox, Dennis S.; Bansal, Narottam P.; Miller, Robert A.

    2004-01-01

    HfO2-Y2O3 and La2Zr2O7 are candidate thermal/environmental barrier coating materials for gas turbine ceramic matrix composite (CMC) combustor liner applications because of their relatively low thermal conductivity and high temperature capability. In this paper, thermal conductivity and high temperature phase stability of plasma-sprayed coatings and/or hot-pressed HfO2-5mol%Y2O3, HfO2- 15mol%Y2O3 and La2Zr2O7 were evaluated at temperatures up to 1700 C using a steady-state laser heat-flux technique. Sintering behavior of the plasma-sprayed coatings was determined by monitoring the thermal conductivity increases during a 20-hour test period at various temperatures. Durability and failure mechanisms of the HfO2-Y2O3 and La2Zr2O7 coatings on mullite/SiC Hexoloy or CMC substrates were investigated at 1650 C under thermal gradient cyclic conditions. Coating design and testing issues for the 1650 C thermaVenvironmenta1 barrier coating applications will also be discussed.

  18. Thermal Conductivity and Water Vapor Stability of Ceramic HfO2-Based Coating Materials

    Science.gov (United States)

    Zhu, Dong-Ming; Fox, Dennis S.; Bansal, Narottam P.; Miller, Robert A.

    2004-01-01

    HfO2-Y2O3 and La2Zr2O7 are candidate thermal/environmental barrier coating materials for gas turbine ceramic matrix composite (CMC) combustor liner applications because of their relatively low thermal conductivity and high temperature capability. In this paper, thermal conductivity and high temperature phase stability of plasma-sprayed coatings and/or hot-pressed HfO2-5mol%Y2O3, HfO2-15mol%Y2O3 and La2Zr2O7 were evaluated at temperatures up to 1700 C using a steady-state laser heat-flux technique. Sintering behavior of the plasma-sprayed coatings was determined by monitoring the thermal conductivity increases during a 20-hour test period at various temperatures. Durability and failure mechanisms of the HfO2-Y2O3 and La2Zr2O7 coatings on mullite/SiC Hexoloy or CMC substrates were investigated at 1650 C under thermal gradient cyclic conditions. Coating design and testing issues for the 1650 C thermal/environmental barrier coating applications will also be discussed.

  19. Gamma radiolysis effects on leaching behavior of ceramic materials for nuclear fuel waste immobilization containers

    International Nuclear Information System (INIS)

    The leaching behavior of ceramic materials for nuclear fuel waste immobilization containers, under the influence of a moderate gamma dose rate (4 Gy/h), has been investigated. Samples of Al/sub 2/O/sub 3/, stabilized ZrO/sub 2/, TiO/sub 2/, cermet (70% Al/sub 2/O-30% TiC), porcelain (with high Al/sub 2/O/sub 3/ content), and concrete (with sulfate-resisting portland cement plus silica fume) have been leached in Standard Canadian Shield Saline Solution (SCSSS), and SCSSS plus clay and sand (components of the disposal system), at 1000 and 1500C for 231 and 987 days, respectively. Leaching solutions were analyzed and the surfaces of the leached samples were investigated by scanning electron microscopy in conjunction with energy dispersive X-ray spectroscopy and secondary ion mass spectrometry. Radiolysis did not appear to enhance the leaching, with or without bentonite and sand in the system. Analysis of the gas phase from sealed capsules showed O/sub 2/ depletion and production of CO/sub 2/ in all experiments containing bentonite. The decrease in O/sub 2/ is attributed to the leaching from the clay of Fe(II) species, which can participate in redox reactions with radicals generated by radiolysis. The CO/sub 2/ is produced from either the organic or inorganic fraction in the bentonite

  20. 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. PMID:25870955

  1. Ultra low and negative expansion glass–ceramic materials produced from pyrophyllite and blast furnace slag

    Indian Academy of Sciences (India)

    S Mandal; S Chakrabarti; S Ghatak; S K Das

    2005-08-01

    Ultra low and negative expansion glass–ceramic materials have been obtained from pyrophyllite and blast furnace slag. The batch composition was modified with the addition of lithium carbonate, hydrated alumina, boric acid and nucleating agent (titania). The batch was melted at 1400°C followed by casting in the form of bars and annealed at 510°C for 4 h. The annealed specimens were subjected to heat treatment at predetermined temperatures selected from DTA study of the parent glass. Thermal expansion measurement and X-ray diffraction analysis revealed that the specimen nucleated at 545°C for 4 h and crystallized at 720°C for 2 h which resulted in negative coefficient of thermal expansion [(–) 9 to (–) 2 × 10$^{-7}/{}^\\circ $C] over the temperature range (30–600°C) due to the formation of -eucryptite while other heating schedule showed the formation of spodumene and lithium aluminium silicates. The samples showed excellent flexural strength value and varied in the range 120–200 MPa depending upon the phases present.

  2. Inhibitory Effects of Far-Infrared Irradiation Generated by Ceramic Material on Murine Melanoma Cell Growth

    Directory of Open Access Journals (Sweden)

    Ting-Kai Leung

    2012-01-01

    Full Text Available The biological effects of specific wavelengths, so-called “far-infrared radiation” produced from ceramic material (cFIR, on whole organisms are not yet well understood. In this study, we investigated the biological effects of cFIR on murine melanoma cells (B16-F10 at body temperature. cFIR irradiation treatment for 48 h resulted in an 11.8% decrease in the proliferation of melanoma cells relative to the control. Meanwhile, incubation of cells with cFIR for 48 h significantly resulted in 56.9% and 15.7% decreases in the intracellular heat shock protein (HSP70 and intracellular nitric oxide (iNO contents, respectively. Furthermore, cFIR treatment induced 6.4% and 12.3% increases in intracellular reactive oxygen species stained by 5-(and 6-carboxyl-2′,7′-dichlorodihydrofluorescein diacetate and dihydrorhodamine 123, respectively. Since malignant melanomas are known to have high HSP70 expression and iNO activity, the suppressive effects of cFIR on HSP70 and NO may warrant future interest in antitumor applications.

  3. Production of continuous piezoelectric ceramic fibers for smart materials and active control devices

    Science.gov (United States)

    French, Jonathan D.; Weitz, Gregory E.; Luke, John E.; Cass, Richard B.; Jadidian, Bahram; Bhargava, Parag; Safari, Ahmad

    1997-05-01

    Advanced Cerametrics Inc. has conceived of and developed the Viscous-Suspension-Spinning Process (VSSP) to produce continuous fine filaments of nearly any powdered ceramic materials. VSSP lead zirconate titanate (PZT) fiber tows with 100 and 790 filaments have been spun in continuous lengths exceeding 1700 meters. Sintered PZT filaments typically are 10 - 25 microns in diameter and have moderate flexibility. Prior to carrier burnout and sintering, VSSP PZT fibers can be formed into 2D and 3D shapes using conventional textile and composite forming processes. While the extension of PZT is on the order of 20 microns per linear inch, a woven, wound or braided structure can contain very long lengths of PZT fiber and generate comparatively large output strokes from relatively small volumes. These structures are intended for applications such as bipolar actuators for fiber optic assembly and repair, vibration and noise damping for aircraft, rotorcraft, automobiles and home applications, vibration generators and ultrasonic transducers for medical and industrial imaging. Fiber and component cost savings over current technologies, such as the `dice-and-fill' method for transducer production, and the range of unique structures possible with continuous VSSP PZT fiber are discussed. Recent results have yielded 1-3 type composites (25 vol% PZT) with d33 equals 340 pC/N, K equals 470, and g33 equals 80 mV/N, kt equals 0.54, kp equals 0.19, dh equals 50.1pC/N and gh equals 13 mV/N.

  4. Extended defects in insulating MgAl2O4 ceramic materials studied by PALS methods

    International Nuclear Information System (INIS)

    Extended positron-trapping defects in technological modified insulating nanoporous MgAl2O4 ceramics are characterized by positron annihilation lifetime spectroscopy. The results are achieved using three-component fitting procedure with arbitrary lifetimes applied to treatment of measured spectra. Within this approach, the first component in the lifetime spectra reflects microstructure specificity of the spinel structure, the second component responsible to extended defects near intergranual boundaries and the third component correspond to ortho-positronium 'pick-off' decaying in nanopores of ceramics. It is shown that in ceramics of different technological modifications the same type of positron traps prevails.

  5. Application of design of experiment on electrophoretic deposition of glass-ceramic coating materials from an aqueous bath

    Indian Academy of Sciences (India)

    Someswar Datta

    2000-04-01

    A process for application of abrasion- or corrosion-resistant glass-ceramic coating materials on metal substrate by electrophoretic deposition technique in an aqueous medium has been described. The effects of various process parameters, e.g. coating material concentration, time of deposition, applied current, pH of the suspension and concentration of the polymeric dispersant on the deposition efficiency have been studied. The process has been studied using a 23-factorial design technique of three independent variables; i.e. coating material concentration, applied current, and the time taken to achieve the best combination. The regression equation obtained explains the experimental results satisfactorily.

  6. Ceramic materials for chemosensors and their application in oil quality control

    International Nuclear Information System (INIS)

    In this work a sensor prototype is presented which allows permanent monitoring of the degradation process in automotive engine oils. To this end, sensitive layers were developed which guarantee the selective inclusion of compounds that are specific for used oil. By applying the sol-gel technique, oxide ceramics were obtained that combine high chemical selectivity and sensitivity with the thermal and mechanical stability necessary for use under engine conditions. The great advantage of ceramic layers is the complete absence of functional groups or even organic compounds. The polymerization parameters were characterized using FT-IR and Atomic Force Microscopy prior to optimizing the frequency response of the mass-sensitive transducer (QMB - quartz crystal microbalance). Selectivity was achieved by using the technique of molecular imprinting, with layers imprinted with capric acid showing the most effective reinclusion. Thermal removal of the imprint leads to no loss of homogeneity of the layer, as opposed to washing out the imprint with ethanol. Thus, a constant signal/noise ratio independent of the layer thickness is ensured. Apart from those in the oil itself, gas-phase measurements were also performed. Here, only the reversibility was not as good as that of liquid phase measurements. The sensors were used for quality control of vegetable oils with equal success. In order to investigate the influence of precursor materials on the structure, porosity, selectivity and sensitivity of the used TiO2-layers, the response to different solvents was tested in gas-phase measurements. The correlation of frequency changes to molecule topology indices such as the 'Wiener-Index' indicates that geometric limits exist for the inclusion of solvent molecules. An index permitting prediction of sensor effects would contain more parameters, such as molecule diameter, functional groups and polarity. Finally, the suitability of different high-frequency resonators for application in oil

  7. Synthesis of inorganic materials in a supercritical carbon dioxide medium. Application to ceramic cross-flow filtration membranes preparation

    International Nuclear Information System (INIS)

    Membrane separations, using cross-flow mineral ceramic membranes, allows fractionation of aqueous solutions due to the molecular sieve effect and electrostatic charges. To obtain a high selectivity, preparation of new selective ceramic membranes is necessary. We propose in this document two different routes to prepare such cross-flow tubular mineral membranes. In the first exposed method, a ceramic material is used, titanium dioxide, synthesized in supercritical carbon dioxide by the hydrolysis of an organometallic precursor of the oxide. The influence of operating parameters is similar to what is observed during a liquid-phase synthesis (sol-gel process), and leads us to control the size and texture of the prepared particles. This material is then used to prepare mineral membrane with a compressed layer process. The particles are mixed with organic components to form a liquid suspension. A layer is then deposited on the internal surface of a tubular porous support by slip-casting. The layer is then dried and compressed on the support before sintering. The obtained membranes arc in the ultrafiltration range. A second process has been developed in this work. It consists on the hydrolysis, in a supercritical CO2 medium, of a precursor of titanium dioxide infiltrated into the support. The obtained material is then both deposited on the support but also infiltrated into the porosity. This new method leads to obtain ultrafiltration membranes that retain molecules which molecular weight is round 4000 g.mol-1. Furthermore, we studied mass transfer mechanisms in cross-flow filtration of aqueous solutions. An electrostatic model, based on generalized Nernst-Planck equation that takes into account electrostatic interactions between solutes and the ceramic material, lead us to obtain a good correlation between experimental results and the numerical simulation. (author)

  8. Standard test method for linear thermal expansion of glaze frits and ceramic whiteware materials by the interferometric method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1995-01-01

    1.1 This test method covers the interferometric determination of linear thermal expansion of premelted glaze frits and fired ceramic whiteware materials at temperatures lower than 1000°C (1830°F). 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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

    International Nuclear Information System (INIS)

    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

  10. 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.

  11. Use of residues proceeding from marbles and granites finishing and manufacturing processes as raw material for structural ceramic

    International Nuclear Information System (INIS)

    In order to decrease environmental impact, caused by mud discarding and clay extraction in the ceramic industry, it was used residual mud from marble and granite companies for structural ceramic. Samples were collected in twelve different marble companies located at the metropolitan region of Sao Paulo. However, only four samples were selected, based on its different characteristics. Clay stone was the raw material chosen to prepare the structural ceramic, considering its high use in this segment. Samples and clay stone were both analysed by the following procedures: granulometric analysis, x-rays fluorescent chemical analysis and x-rays diffraction mineralogical analysis, besides, tests in the samples were conducted following NBR 10004 standards. Once raw materials were characterized, the plasticity test was conducted. Test specimen were molded with different levels of mud, then burned and submitted to technological tests, such as: mechanical resistance, water absorption, porosity, specific gravity and retraction, material dilation before burning process and scanning electron microscopy. The final results have shown the viability of using this kind of mud, and pointed some advantages on its usage, but taking in consideration some previous conditions to be adopted. (author)

  12. Influence of Dental Alloys and an All-Ceramic Material on Cell Viability and Interleukin-1beta Release in a Three-Dimensional Cell Culture Model

    OpenAIRE

    ÖZEN, Jülide; Ural, Ali Uğur; Dalkiz, Mehmet; BEYDEMİR, Bedri

    2005-01-01

    The purpose of this study was to determine the influence of various types of dental casting alloys and ceramic upon cell viability and the synthesis of IL-1beta (b) in a three-dimensional cell culture system consisting of human gingival fibroblast, and to determine their effect in gingival inflammation. Au-Pt-In alloy (Pontostar), Ni-Cr-Mo alloy (Remanium-CS), a titanium alloy (Ti-6Al-4V), copper (Cu), and an all ceramic (In-Ceram) were used as test materials. The materials were exposed to a ...

  13. Effects of neutron irradiation on glass ceramics as pressure-less joining materials for SiC based components for nuclear applications

    Czech Academy of Sciences Publication Activity Database

    Ferraris, M.; Casalegno, V.; Rizzo, S.; Salvo, M.; Van Staveren, T.O.; Matějíček, Jiří

    2012-01-01

    Roč. 429, 1-3 (2012), s. 166-172. ISSN 0022-3115 R&D Projects: GA MPO 2A-1TP1/101 Institutional research plan: CEZ:AV0Z20430508 Keywords : glass-ceramic * joining * SiC composites * fusion materials Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.211, year: 2012 http://www.sciencedirect.com/science/article/pii/S0022311512002668

  14. Stress relaxation and creep of high-temperature gas-cooled reactor core support ceramic materials: a literature search

    International Nuclear Information System (INIS)

    Creep and stress relaxation in structural ceramics are important properties to the high-temperature design and safety analysis of the core support structure of the HTGR. The ability of the support structure to function for the lifetime of the reactor is directly related to the allowable creep strain and the ability of the structure to withstand thermal transients. The thermal-mechanical response of the core support pads to steady-state stresses and potential thermal transients depends on variables, including the ability of the ceramics to undergo some stress relaxation in relatively short times. Creep and stress relaxation phenomena in structural ceramics of interest were examined. Of the materials considered (fused silica, alumina, silicon nitride, and silicon carbide), alumina has been more extensively investigated in creep. Activation energies reported varied between 482 and 837 kJ/mole, and consequently, variations in the assigned mechanisms were noted. Nabarro-Herring creep is considered as the primary creep mechanism and no definite grain size dependence has been identified. Results for silicon nitride are in better agreement with reported activation energies. No creep data were found for fused silica or silicon carbide and no stress relaxation data were found for any of the candidate materials. While creep and stress relaxation are similar and it is theoretically possible to derive the value of one property when the other is known, no explicit demonstrated relationship exists between the two. For a given structural ceramic material, both properties must be experimentally determined to obtain the information necessary for use in high-temperature design and safety analyses

  15. Ceramic electrolyte coating and methods

    Science.gov (United States)

    Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

    2007-08-28

    Aqueous coating slurries useful in depositing a dense coating of a ceramic electrolyte material (e.g., yttrium-stabilized zirconia) onto a porous substrate of a ceramic electrode material (e.g., lanthanum strontium manganite or nickel/zirconia) and processes for preparing an aqueous suspension of a ceramic electrolyte material and an aqueous spray coating slurry including a ceramic electrolyte material. The invention also includes processes for depositing an aqueous spray coating slurry including a ceramic electrolyte material onto pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

  16. Tailored ceramics

    International Nuclear Information System (INIS)

    In polyphase tailored ceramic forms two distinct modes of radionuclide immobilization occur. At high waste loadings the radionuclides are distributed through most of the ceramic phases in dilute solid solution, as indicated schematically in this paper. However, in the case of low waste loadings, or a high loading of a waste with low radionuclide content, the ceramic can be designed with only selected phases containing the radionuclides. The remaining material forms nonradioactive phases which provide a degree of physical microstructural isolation. The research and development work with polyphase ceramic nuclear waste forms over the past ten years is discussed. It has demonstrated the critical attributes which suggest them as a waste form for future HLW disposal. From a safety standpoint, the crystalline phases in the ceramic waste forms offer the potential for demonstrable chemical durability in immobilizing the long-lived radionuclides in a geologic environment. With continued experimental research on pure phases, analysis of mineral analogue behavior in geochemical environments, and the study of radiation effects, realistic predictive models for waste form behavior over geologic time scales are feasible. The ceramic forms extend the degree of freedom for the economic optimization of the waste disposal system

  17. Influence of surface treatments on bond strength of metal and ceramic brackets to a novel CAD/CAM hybrid ceramic material.

    Science.gov (United States)

    Elsaka, Shaymaa E

    2016-01-01

    This study evaluated the effect of four different surface treatments methods on the shear bond strength (SBS) of ceramic and metal brackets to Vita Enamic (VE) CAD/CAM hybrid ceramic. A total of 240 plates (10 mm × 10 mm × 3 mm) were cut from VE ceramic blocks and divided into two groups. In each group, four subgroups were prepared by hydrofluoric acid (HF); phosphoric acid (H3PO4); diamond ceramic grinding bur; and silica coating using CoJet system (CJ). Maxillary central incisor metal (Victory Series) and ceramic (Clarity) brackets were bonded with light-cure composite and then stored in artificial saliva for 1 week and thermocycled. The SBS test was performed, and the failure types were classified with adhesive remnant index scores. Surface morphology of the ceramic was characterized after treatment using a scanning electron microscope. Data were analyzed using two-way ANOVA, Tukey HSD test, and Weibull analysis. SBS was significantly affected by the type of bracket and by type of treatment (P HF > Bur > H3PO4. Ceramic bracket showed higher SBS compared to metal bracket. Adhesive failures between the ceramic and composite resin were the predominant mode of failure in all groups. Surface treatment of VE CAD/CAM hybrid ceramic with silica coating enhanced the adhesion with ceramic and metal brackets. PMID:25585677

  18. Environmental durability of ceramics and ceramic composites

    Science.gov (United States)

    Fox, Dennis S.

    1992-01-01

    An account is given of the current understanding of the environmental durability of both monolithic ceramics and ceramic-matrix composites, with a view to the prospective development of methods for the characterization, prediction, and improvement of ceramics' environmental durability. Attention is given to the environmental degradation behaviors of SiC, Si3N4, Al2O3, and glass-ceramic matrix compositions. The focus of corrosion prevention in Si-based ceramics such as SiC and Si3N4 is on the high and low sulfur fuel combustion-product effects encountered in heat engine applications of these ceramics; sintering additives and raw material impurities are noted to play a decisive role in ceramics' high temperature environmental response.

  19. 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.

  20. He-irradiation effects on glass-ceramics for joining of SiC-based materials

    Science.gov (United States)

    Gozzelino, L.; Casalegno, V.; Ghigo, G.; Moskalewicz, T.; Czyrska-Filemonowicz, A.; Ferraris, M.

    2016-04-01

    CaO-Al2O3 (CA) and SiO2-Al2O3-Y2O3 (SAY) glass-ceramics are promising candidates for SiC/SiC indirect joints. In view of their use in locations where high radiation level is expected (i.e. fusion plants) it is important to investigate how radiation-induced damage can modify the material microstructure. To this aim, pellets of both types were irradiated with 5.5 MeV 4He+ ions at an average temperature of 75 °C up to a fluence of almost 2.3·1018 cm-2. This produces a displacement defect density that increases with depth and reaches a value of about 40 displacements per atom in the ion implantation region, where the He-gas reaches a concentration of several thousands of atomic parts per million. X-ray diffractometry and scanning electron microscopy showed no change in the microstructure and in the morphology of the pellet surface. Moreover, a transmission electron microscopy investigation on cross-section lamellas revealed the occurrence of structural defects and agglomerates of He-bubbles in the implantation region for the CA sample and a more homogeneous He-bubble distribution in the SAY pellet, even outside the implantation layer. In addition, no amorphization was found in both samples, even in correspondence to the He implantation zone. The radiation damage induced only occasional micro-cracks, mainly located at grain boundaries (CA) or within the grains (SAY).

  1. Polymer-derived-SiCN ceramic/graphite composite as anode material with enhanced rate capability for lithium ion batteries

    Science.gov (United States)

    Graczyk-Zajac, M.; Fasel, C.; Riedel, R.

    2011-08-01

    We report on a new composite material in view of its application as a negative electrode in lithium-ion batteries. A commercial preceramic polysilazane mixed with graphite in 1:1 weight ratio was transformed into a SiCN/graphite composite material through a pyrolytic polymer-to-ceramic conversion at three different temperatures, namely 950 °C, 1100 °C and 1300 °C. By means of Raman spectroscopy we found successive ordering of carbon clusters into nano-crystalline graphitic regions with increasing pyrolysis temperature. The reversible capacity of about 350 mAh g-1 was measured with constant current charging/discharging for the composite prepared at 1300 °C. For comparison pure graphite and pure polysilazane-derived SiCN ceramic were examined as reference materials. During fast charging and discharging the composite material demonstrates enhanced capacity and stability. Charging and discharging in half an hour lead to about 200 and 10 mAh g-1, for the composite annealed at 1300 °C and pure graphite, respectively. A clear dependence between the final material capacity and pyrolysis temperature is found and discussed with respect to possible application in batteries, i.e. practical discharging potential limit. The best results in terms of capacity recovered under 1 V and high rate capability were also obtained for samples synthesized at 1300 °C.

  2. In-flight behavior of dissimilar co-injected particles in the spraying of metal-ceramic functionally gradient materials

    Energy Technology Data Exchange (ETDEWEB)

    Fincke, J.R.; Swank, W.D.; Haggard, D.C. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1997-12-31

    In the spraying of functionally gradient coatings the particle ensemble delivered to the substrate can vary from a relatively low melting point metallic particle to a significantly higher melting point ceramic particle. At various stages in the spray process the particle ensemble can be either predominantly metallic, ceramic, or an intermediate combination. For co-injected particles the mixtures do not behave as a simple linear superposition of the spray patterns of the individual particle types. The particle temperature, velocity, size distributions, and pattern characteristics of the resulting spray fields is examined for all ceramic particle sprays (ZrO{sub 2}), all metallic particle sprays (NiCrAlY), and for a 1:1 mixture. The major particle-particle interaction occurs in the injector itself and results in a modified spray pattern which is different from that of either material sprayed alone. The particle velocity distributions generally exhibit a bimodal nature which is dependent on the size and density of the injected particles.

  3. 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.

  4. The archaeometric study of ceramic materials in JCR journals and conference proceedings during the last decade (2000-2010)

    International Nuclear Information System (INIS)

    Ceramic is the oldest synthetic material created by the mankind and has been present in human societies from around ten thousand years ago. During the last few decades, within the research field of Archaeometry, the study of archaeological and historical ceramic materials has experienced a significant increase in the application of chemical-physical techniques to obtain information on technology and production of these materials in the past. This paper presents the results obtained in a bibliometric study undertaken on 589 articles published on this subject in JCR journals and conference proceedings during the last decade (2000-2010). The main purpose of this research was to address the recent evolution and trends of this kind of investigations. The parameters analyzed were: date of publication, type of journal, topic, cultural-chronological classification of materials studied, origin country of authors, and analytical techniques used. Resulting data indicated a continual, stable, and growing publication rate on the subject in journals and conference proceedings of the three JCR indexes, namely SCI, AHCI, and SSCI, which evidences a high level of interdisciplinary. Authors from Europe and the United States carried out the majority of contributions. (Author) 30 refs.

  5. Use of sugar-cane bagasse ash to produce glass-ceramic material in the system Ca O-SiO2-Na2O

    International Nuclear Information System (INIS)

    A bottom ash was used as raw material to obtain glass which was crystallized to form glass-ceramic material. The characterization of the ash shows that it consists mainly of crystalline materials, predominantly quartz, with oxides of iron, potassium and aluminum as minor elements. The glass was obtained from the mixing of ash with calcium and sodium carbonates. The glass and the glass-ceramic were examined using differential thermal analysis (DTA), X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD and DTA data show that Wollastonita is the only crystalline phase present in the material crystallized at 1050 deg C. Part of the glass was synthesized at this temperature for one hour, resulting in a green/brown hard material glass-ceramic. The images of SEM show morphology of spherilithic growth indicating volumetric crystallization mechanism. (author)

  6. Evaluation of performance of materials used in the ceramic materials restoration of the Plaza de España (Sevilla

    Directory of Open Access Journals (Sweden)

    Alejandre Sánchez, F. J.

    2005-06-01

    Full Text Available Different commercial mortars and stuecos used to cold restore the glazing on deteriorated tile in Seville s Plaza de España were tested for performance and durability. Five types of samples were applied to ceramic bisques and subsequently coloured and protected with resins. The samples were subjected to accelerated weathering consisting in salt crystallization, temperature and relative humidity cycles and ultraviolet radiation. Durability was assessed by visually comparing the effect of salt crystallization, determining the colour parameters with colourimetry and measuring adherence and capillary water absorption. The results obtained were used to differentiate the materials tested in two respects: stucco and protective resin performance under the environmental conditions prevailing in the Plaza de España on the one hand and colour stability on the other.

    En el presente trabajo se estudia el comportamiento y la durabilidad de diferentes morteros y estucos comerciales que se han utilizado para restituir enfrío las pérdidas de vidriado en azulejos deteriorados de la Plaza de España (Sevilla. Para ello se han preparado 5 tipos de muestras que se han aplicado sobre bizcochos cerámicos y que posteriormente se han coloreado y protegido con resinas. Las muestras se han sometido a ensayos de alteración acelerada: cristalización de sales, ciclos de temperatura y humedad relativa, y radiación ultravioleta. La evaluación de la durabilidad se ha llevado a cabo mediante la comparación visual del efecto de cristalización de las sales, la determinación de los parámetros de color mediante colorimetría, de la adherencia y de la absorción de agua por capilaridad. Los resultados obtenidos, permiten realizar una diferenciación en dos aspectos, por un lado, el comportamiento del estuco y su protección para soportar las condiciones medioambientales de la Plaza de España, y, por otro, la estabilidad de los diferentes colores.

  7. Shear Bond Strengths between Three Different Yttria-Stabilized Zirconia Dental Materials and Veneering Ceramic and Their Susceptibility to Autoclave Induced Low-Temperature Degradation

    OpenAIRE

    Manoti Sehgal; Akshay Bhargava; Sharad Gupta; Prateek Gupta

    2016-01-01

    A study was undertaken to evaluate the effect of artificial aging through steam and thermal treatment as influencing the shear bond strength between three different commercially available zirconia core materials, namely, Upcera, Ziecon, and Cercon, layered with VITA VM9 veneering ceramic using Universal Testing Machine. The mode of failure between zirconia and ceramic was further analyzed as adhesive, cohesive, or mixed using stereomicroscope. X-ray diffraction and SEM (scanning electron micr...

  8. ESCA [electron spectroscopy for chemical analysis] examination of metal oxides and electronic ceramic materials: The effect of a low-energy argon-ion beam

    International Nuclear Information System (INIS)

    Electronic ceramic materials are increasingly of interest to chemists because there is a growing interest in preparing high purity ceramics by chemical means and because the properties of the ceramics often depend on the chemical state of the elements in the ceramic. The chemical species, e.g. the oxidation state, of a metal in a ceramic can be identified by the analytical technique known as ESCA (electron spectroscopy for chemical analysis). In this work, the application of ESCA to ceramic materials begins with studies of metal oxide powders and examines the effect of a low energy argon ion beam. Two problems that occur with oxide powders and ceramics are surface charging and the formation of carbonates on the surface. Surface charging is generally compensated for by referencing to the carbon contaminant or by flooding the surface with electrons. Referencing to the contaminant peak meets with limited success when compared to the literature. Flooding the surface of oxide powders and ceramics causes peak distortion. Surface carbonates are identified in the carbon region by their separation of -4.5 eV from the contaminant carbon. To examine the effect of a low energy ion beam on metal oxide powders and ceramic powders, both the X-ray photoelectron (XPS) and X-ray induced Auger electron spectra (XAES) of SC2O3, V2O5, Cu2 O, ZnO and SnO2 are examined before and after ion beam exposure. Limited reduction of the metal is noted in the XPS spectra of V2O5. XAES indicates the Sc2O3, Cu2O and SnO2 are also reduced. XAES is especially useful for determining that reduction by the ion beam has occurred. A comparison of ion beam exposed oxide powders and heavily oxidized metal foils (Ti, Zr and Nb) shows that while the powders undergo limited reduction, the oxidized foils are reduced much more significantly with the same sputtering parameters

  9. High gamma-ray measurement using optical emission of ceramic material

    Energy Technology Data Exchange (ETDEWEB)

    Kakuta, Tsunemi; Sakasai, Kaoru; Yamagishi, Hideshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakazawa, Masaharu

    1996-07-01

    This paper describes the fluorescence phenomena in Zr-O ceramic under expose to high gamma-ray and fission neutron source. In addition, the paper also discusses the possibility of ionizing radiation detection in the core region of reactor. (J.P.N.)

  10. Military Curriculum Materials for Vocational and Technical Education. Builders School, Ceramic Tile Setting 3-9.

    Science.gov (United States)

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This course, for individualized or group instruction on ceramic tile setting, was developed from military sources for use in vocational education. The course provides students with skills in mortar preparation, surface preparation, tile layout planning, tile setting, tile cutting, and the grouting of tile joints. Both theory and shop assignments…

  11. Clinical application of bio ceramics

    Science.gov (United States)

    Anu, Sharma; Gayatri, Sharma

    2016-05-01

    Ceramics are the inorganic crystalline material. These are used in various field such as biomedical, electrical, electronics, aerospace, automotive and optical etc. Bio ceramics are the one of the most active areas of research. Bio ceramics are the ceramics which are biocompatible. The unique properties of bio ceramics make them an attractive option for medical applications and offer some potential advantages over other materials. During the past three decades, a number of major advances have been made in the field of bio ceramics. This review focuses on the use of these materials in variety of clinical scenarios.

  12. 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.

  13. Development of method to remove weld scallop and ceramic backing material of wedge type and its application

    OpenAIRE

    Kang Sung-Koo; Yang Jong-Soo; Kim Ho-Kyung

    2015-01-01

    The weld scallop has been used for joining T-bars. There are a lot of weld scallops in shipbuilding. It is difficult to perform scallop welding due to the inconvenient welding position. This results in many problems such as porosity, slag inclusion, etc. In this study, a new method is devised to remove weld scallops by incorporating a Ceramic Backing Material (CBM). The weld scallop is removed by an elongation of the v groove. In order to insert a CBM into the groove without a weld scallop, a...

  14. THE UTILIZATION OF Fe(III) WASTE OF ETCHING INDUSTRY AS QUALITY ENHANCHEMENT MATERIAL IN CERAMIC ROOFTILE SYNTHESIS

    OpenAIRE

    Eva Vaulina Yulistia Delsy; Dwi Kartika; Wilma Aziza

    2015-01-01

    Waste is produced from various industrial activities. FeCl3 used in this study as an addition to the material quality in synthesis of ceramic rooftile from Kalijaran village clay, Purbalingga. Etching industrial waste FeCl3 contacted with clay. Waste being varied waste as diluted and undiluted while clay grain size varied as 60, 80, 100, 140, and 230 mesh. Both clay and waste are contacted at 30-100 minutes. The results showed that the optimum of time and grain size variation is clay with 80...

  15. Crystal chemistry of uranium (V) and plutonium (IV) in a titanate ceramic for disposition of surplus fissile material

    Science.gov (United States)

    Fortner, J. A.; Kropf, A. J.; Finch, R. J.; Bakel, A. J.; Hash, M. C.; Chamberlain, D. B.

    2002-07-01

    We report X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectra for the plutonium LIII and uranium LIII edges in titanate pyrochlore ceramic. The titanate ceramics studied are of the type proposed to serve as a matrix for the immobilization of surplus fissile materials. The samples studied contain approximately 10 wt% fissile plutonium and 20 wt% natural uranium, and are representative of material within the planned production envelope. Based upon natural analogue models, it had been previously assumed that both uranium and plutonium would occupy the calcium site in the pyrochlore crystal structure. While the XANES and EXAFS signals from the plutonium LIII are consistent with this substitution into the calcium site within pyrochlore, the uranium XANES is characteristic of pentavalent uranium. Furthermore, the EXAFS signal from the uranium has a distinct oxygen coordination shell at 2.07 Å and a total oxygen coordination of about 6, which is inconsistent with the calcium site. These combined EXAFS and XANES results provide the first evidence of substantial pentavalent uranium in an octahedral site in pyrochlore. This may also explain the copious nucleation of rutile (TiO 2) precipitates commonly observed in these materials as uranium displaces titanium from the octahedral sites.

  16. Influence of corn flour as pore forming agent on porous ceramic material based mullite: Morphology and mechanical properties

    Directory of Open Access Journals (Sweden)

    Ayala-Landeros J.G.

    2016-01-01

    Full Text Available Porous material was processed by the mixing, molding and pressing the ceramic material, afterward burnout and sintering; through the forming porous, using corn flour at different concentration (10, 15 and 20 wt.% as a pore forming agent; in order to determinate the influence of porous on the mechanical, morphological and structural properties. The effect of the volume fraction of corn flour in the mullite matrix, at various sintering temperature from 1100, 1200, 1300 and 1500°C were tested by Diffraction X ray, showing changes in crystalline phases of mullite (3Al2O3-2SiO2, as result of sintered temperatures. Presence of talcum powder in formula, also cause the formation of the cordierite and cristobalite crystalline phases, giving stability and adhesion to the structure of ceramic material. When sintering at temperatures between 1300 to 1500°C, and it was used the concentration of corn flour 15-20 wt.% as forming agent porous, it was found the better mechanical properties. The scanning electron microscopy analysis shows the presence of open porosity and anisotropy.

  17. High-temperature bending strength and microstructure of Al2O3/ZrO2 ceramics composite materials. Al2O3/ZrO2 ceramics fukugo zairyo no koon mage kyodo to bisai kozo

    Energy Technology Data Exchange (ETDEWEB)

    Hisamori, N.; Kimura, Y. (Kogakuin University, Tokyo (Japan))

    1998-05-21

    A high-temperature strength test was carried out on Al2O3/ZrO2 ceramics composite materials to discuss correlation between high-temperature strength and microstructure thereof. The experiment used as a test material Al2O3/ZrO2 ceramics composite material sinters, in which Al2O3 is used as a base material, and tetragonal stabilized ZrO2 particles are dispersed in three kinds of ratios, 5, 15 and 30% by weight. The sintering temperatures were 1500, 1550, 1600 and 1650 degC. The high-temperature bending test was performed for three-point bending in atmosphere at room temperature, 600, 800 and 1000 degC. The following conclusions were obtained as a result of the discussions: Al2O3/ZrO2 ceramics composite material sinters can be improved of their strength even at elevated temperatures by adding ZrO2 particles while suppressing the addition to an extent that no strength deterioration would occur due to high-temperature corrosion and by sintering the materials at low temperatures to achieve microstructure; and, according to the result of observing the microstructure, single Al2O3 materials having lower strength than composite materials may have relatively large pores and inclusions inside the sinters and in the vicinity of the surface cause to work as fracture paths. 3 figs.

  18. New Effective Material Couple--Oxide Ceramic and Carbon Nanotube-- Developed for Aerospace Microsystem and Micromachine Technologies

    Science.gov (United States)

    Miyoshi, Kazuhisa; VanderWal, Randall L.; Tomasek, Aaron J.; Sayir, Ali; Farmer, Serene C.

    2004-01-01

    The prime driving force for using microsystem and micromachine technologies in transport vehicles, such as spacecraft, aircraft, and automobiles, is to reduce the weight, power consumption, and volume of components and systems to lower costs and increase affordability and reliability. However, a number of specific issues need to be addressed with respect to using microsystems and micromachines in aerospace applications--such as the lack of understanding of material characteristics; methods for producing and testing the materials in small batches; the limited proven durability and lifetime of current microcomponents, packaging, and interconnections; a cultural change with respect to system designs; and the use of embedded software, which will require new product assurance guidelines. In regards to material characteristics, there are significant adhesion, friction, and wear issues in using microdevices. Because these issues are directly related to surface phenomena, they cannot be scaled down linearly and they become increasingly important as the devices become smaller. When microsystems have contacting surfaces in relative motion, the adhesion and friction affect performance, energy consumption, wear damage, maintenance, lifetime and catastrophic failure, and reliability. Ceramics, for the most part, do not have inherently good friction and wear properties. For example, coefficients of friction in excess of 0.7 have been reported for ceramics and ceramic composite materials. Under Alternate Fuels Foundation Technologies funding, two-phase oxide ceramics developed for superior high-temperature wear resistance in NASA's High Operating Temperature Propulsion Components (HOTPC) project and new two-layered carbon nanotube (CNT) coatings (CNT topcoat/iron bondcoat/quartz substrate) developed in NASA's Revolutionary Aeropropulsion Concepts (RAC) project have been chosen as a materials couple for aerospace applications, including micromachines, in the nanotechnology

  19. Effect of glycine pretreatment on the shear bond strength of a CAD/CAM resin nano ceramic material to dentin

    Science.gov (United States)

    Ceci, Matteo; Pigozzo, Marco; Scribante, Andrea; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco

    2016-01-01

    Background The purpose of this study was to evaluate the effect of glycine pretreatment on the shear bond strength between dentin and a CAD/CAM resin nano ceramic material (LavaTM Ultimate Restorative), bonded together with adhesive cements using three different luting protocols (total-etch; self-etch; self-adhesive). Material and Methods Thirty cylinders were milled from resin nano ceramic blocks with CAD/CAM technology. The cylinders were subsequently cemented to the exposed dentin of 30 bovine permanent mandibular incisors. The specimens were assigned into six groups of five teeth each according to luting procedure and dentin pretreatment. In the first two groups (A1, A2) 10 cylinders were cemented using a total-etch protocol; in groups B1 and B2, 10 cylinders were cemented using a self-etch protocol; in groups C1 and C2, 10 cylinders were cemented using a self-adhesive protocol; in groups A1, B1 and C1 the dentinal surface was also treated with glycine powder. All cemented specimens were submitted to a shear bond strength test. Statistical analysis was performed with Stata 9.0 software. Results ANOVA showed the presence of significant differences among the various groups (P <0.0001). Conclusions Glycine did not change the different bond strength demonstrated by the various luting protocols tested. Conventional resin composite cements used together with a self-etch adhesive reported the highest values. However the use of glycine seems to increase the bond strength of self-adhesive resin cements. Key words:Adhesive cements, CAD/CAM, glycine, luting system, resin nano ceramic, shear bond strength. PMID:27034754

  20. Materials and Concepts for Full Ceramic SOFCs with Focus on Carbon Containing Fuels

    DEFF Research Database (Denmark)

    Holtappels, Peter; Sudireddy, Bhaskar Reddy; Veltzé, Sune;

    , stability, and S- tolerance has been investigated. These results and an assessment on a 1 kW system level using CPOX reformed natural gas will be reviewed and further perspectives of the cell concept discussed, especially with respect to efficient operation on high carbon containing fuels....... stimulated the development for full ceramic anodes based on strontium titanates. Furthermore, the Ni-cermet is primarily a hydrogen oxidation electrode and efficiency losses might occur when operating on carbon containing fuels. In a recent European project full ceramic cells comprising CGO/Ni infiltrated Nb......-doped SrTiO3 anodes, and LSM/YSZ cathodes have been developed and tested as single 5 x 5 cm2 cells. The initial performance reached 0.4 W/cm2 at 850 °C and redox tolerance has been proven. The cell concept provides flexibility with respect to the used electro catalysts and their impact on power output...

  1. Evaluation of technological properties of clay ceramics with galvanic sludge as raw material

    International Nuclear Information System (INIS)

    This work investigates the possibility to obtain conventional ceramic-based clay added with galvanic sludge, soda-lime and borosilicate glasses. Initially, increasing levels of galvanic sludge in clay were added at 2%, 5%, and 10%, and burned at 900oC, 1000oC, and 1100oC, respectively. Thereafter, the formulations were analyzed with the addition of 2% sludge and contents of 5%, 10%, and 15% for both glasses. These formulations were burned at 1100oC. The ceramic bodies were obtained by uniaxial pressing and characterized, after burning, to flexural strength, water absorption, and linear shrinkage. In addition, the immobilization of hazardous elements present in sludge was evaluated by leaching tests and solubilization. An improvement at the mechanical properties with the addition of glass, especially with the addition of borosilicate glass was observed. Moreover, leaching and solubilization tests showed that the increasing addition of glass led to a reduction of heavy metals

  2. Use of vitrified urban incinerator waste as raw material for production of sintered glass-ceramics

    OpenAIRE

    Romero, Maximina; Rincón López, Jesús María; Rawlings, Rees D.; Boccaccini, A. R.

    2001-01-01

    The crystallisation behaviour of vitrified industrial waste (fly ash from domiciliary solid waste incineration) was examined by differential thermal analysis, X-ray diffractometry and scanning electron microscopy. It was demonstrated that powder processing route was required to transform the vitrified industrial waste into glass-ceramics products. Time-Temperature-Transformation (TTT) diagrams were drawn for the two main crystalline phases, diopside and wollastonite. The wollastonite existed...

  3. Chemical-technological approach to the selection of ceramic materials with predetermined thermistor properties

    Energy Technology Data Exchange (ETDEWEB)

    Plewa, J.; Altenburg, H. [Fachhochschule Muenster, Steinfurt (Germany). SIMa and Supraleiter-Keramik-Kristalle; Brunner, M. [Fachhochschule Koeln (Germany). Elektronische Bauelemente; Shpotyuk, O.; Vakiv, M. [Scientific Research Co. ' ' Carat' ' , Lviv Scientific Research Inst. of Materials, Lviv (Ukraine)

    2002-07-01

    The selection possibilities of quaternary Cu-Ni-Co-Mn oxide system restricted by cubic spinels (CuMn{sub 2}O{sub 4}, MnCo{sub 2}O{sub 4} and NiMn{sub 2}O{sub 4}) for NTC thermistors application were discussed. Phase compositions, microstructural features and electrical properties of the investigated spinel-structured ceramics were studied in tight connection with technological regimes of their sintering. (orig.)

  4. Quantitative WD-XRF calibration for small ceramic samples and their source material

    OpenAIRE

    De Vleeschouwer, François; Renson, Virginie; Claeys, Philippe; Nys, Karin; Bindler, Richard

    2011-01-01

    International audience A wavelength-dispersive X-ray fluorescence (WD-XRF) calibration is developed for small powdered samples (300mg) with the purpose of analyzing ceramic artifacts that might be available only in limited quantity. This is compared to a conventional calibration using a larger sample mass (2g). The comparison of elemental intensities obtained in both calibrations shows that the decrease in analyzed sample mass results in a linear decrease in measured intensity for the anal...

  5. Effect of raw material ratios on the compressive strength of magnesium potassium phosphate chemically bonded ceramics

    International Nuclear Information System (INIS)

    The compressive strength of magnesium potassium phosphate chemically bonded ceramics is important in biomedical field. In this work, the compressive strength of magnesium potassium phosphate chemically bonded ceramics was investigated with different liquid-to-solid and MgO-to-KH2PO4 ratios. X-ray diffractometer was applied to characterize its phase composition. The microstructure was imaged using a scanning electron microscope. The results showed that the compressive strength of the chemically bonded ceramics increased with the decrease of liquid-to-solid ratio due to the change of the packing density and the crystallinity of hydrated product. However, with the increase of MgO-to-KH2PO4 weight ratio, its compressive strength increased firstly and then decreased. The low compressive strength in lower MgO-to-KH2PO4 ratio might be explained by the existence of the weak phase KH2PO4. However, the low value of compressive strength with the higher MgO-to-KH2PO4 ratio might be caused by lack of the joined phase in the hydrated product. Besides, it has been found that the microstructures were different in these two cases by the scanning electron microscope. Colloidal structure appeared for the samples with lower liquid-to-solid and higher MgO-to-KH2PO4 ratios possibly because of the existence of amorphous hydrated products. The optimization of both liquid-to-solid and MgO-to-KH2PO4 ratios was important to improve the compressive strength of magnesium potassium phosphate chemically bonded ceramics. - Highlights: • High packing density and amorphous hydrated phase improved the compressive strength. • Residual KH2PO4 and poor bonding phase lower the compressive strength. • MPCBC fabricated with optimized parameters had the highest compressive strength

  6. Ceramic materials for obtaining of high-purity niobium and tantalum compounds

    International Nuclear Information System (INIS)

    Meterial, based on quartz ceramics with protective coating of niobium pentaoxide, has been developed. It can be used for manufacture of containers, lining and structural products, designated for operation under conditions of rapid temperature drops and in corrosive medium, containing fluoride vapors. Such products can be used instead of platinum containers in synthesis of high-purity niobium and tantalum pentaoxide and can be recommended for application in chemical industry

  7. 全瓷修复材料的老化性研究%Research on the Aging of All-ceramics Restoration Materials

    Institute of Scientific and Technical Information of China (English)

    张东姣

    2011-01-01

    全瓷修复材料以良好的美学特性、生物相容性和机械性能在临床上得到了广泛的应用,但全瓷冠桥在复杂的口腔环境下常出现老化现象,致使全瓷材料的颜色及机械性能产生变化.研究全瓷材料的老化现象及其规律可为临床全瓷冠桥的可靠性和耐久性评价及其改进提供有效的理论依据.本文就全瓷材料的老化现象对其颜色和机械性能的影响及影响老化的因素作一综述和评价.%All-ceramic crowns and bridges have been widely used for dental restorations owing to their excellent func-tionalityt aesthetics and biocompatibility. However, the premature clinical failure of all-ceramic crowns and bridges may easily occur when they are subjected to the complex environment of oral cavity. In the oral environment, all-ceramic materials are prone to aging. Aging can lead all-ceramic materials to change color, to lower bending strength, and to reduce anti-fracture toughness. There are many factors affecting the aging of the all-ceramic materials, for example, the grain size, the type of stabilizer, the residual stress and the water environment. In order to analyze the aging behavior, to optimize the design of all-ceramic crowns and bridges, and to evaluate the reliability and durability, we review in this paper recent research progress of aging behavior for all-ceramics restoration materials.

  8. Comparison of solvent and sacrificial volume-material-based lamination processes of low-temperature co-fired ceramics tapes

    International Nuclear Information System (INIS)

    The lamination process determines the quality of low temperature co-fired ceramics (LTCC) based spatial structures. This paper compares two methods of the microchannel fabrication process in zero-shrinkage LTCC substrates. The first one is based on a two-step lamination process and uses various sacrificial volume materials (SVM). The second one is based on the cold chemical lamination (CCL) process. On the one hand, the SVM gives the possibility of decreasing the deformation of the three-dimensional (3D) structures during the lamination process. The channel volume is filled with a special fugitive material. It protects the spatial structure from deformation during lamination, and evaporates completely during the co-firing process. The bonding quality and strength depend strongly on the fugitive phase type. On the other hand, the CCL is a solvent-based method. It is another alternative for bonding of green ceramic tapes. A special liquid agent is screen printed on the green tape, which melts the tape surface. Then the tapes are stacked and compressed at room temperature by a printing roll. The influence of each method on the microchannel geometry is analyzed in this paper. The resulting structures' bonding quality and mechanical properties are examined by a scanning electron microscope (SEM)

  9. Joining of SiC ceramic-based materials with ternary carbide Ti3SiC2

    International Nuclear Information System (INIS)

    The joining of two pieces of SiC-based ceramic materials (SiC or Cf/SiC composite) was conducted using Ti3SiC2 as filler in vacuum in the joining temperatures range from 1200 deg. C to 1600 deg. C. The similar chemical reactions took place at the interface between Ti3SiC2 and SiC or Cf/SiC, and became more complete with joining temperature increases, and with the consequent increased joining strengths of the SiC and Cf/SiC joints. Based on the XRD and SEM analyses, it turns out that two reasons are most important for the high joining strengths of the SiC and Cf/SiC joints. One is the development of layered Ti3SiC2 ceramic, which has plasticity in nature and can contribute to thermal stress relaxation of the joints; the other is the chemical reactions between Ti3SiC2 and the base materials which result in good interface bonding.

  10. Comparison of solvent and sacrificial volume-material-based lamination processes of low-temperature co-fired ceramics tapes

    Science.gov (United States)

    Malecha, Karol; Jurków, Dominik; Golonka, Leszek J.

    2009-06-01

    The lamination process determines the quality of low temperature co-fired ceramics (LTCC) based spatial structures. This paper compares two methods of the microchannel fabrication process in zero-shrinkage LTCC substrates. The first one is based on a two-step lamination process and uses various sacrificial volume materials (SVM). The second one is based on the cold chemical lamination (CCL) process. On the one hand, the SVM gives the possibility of decreasing the deformation of the three-dimensional (3D) structures during the lamination process. The channel volume is filled with a special fugitive material. It protects the spatial structure from deformation during lamination, and evaporates completely during the co-firing process. The bonding quality and strength depend strongly on the fugitive phase type. On the other hand, the CCL is a solvent-based method. It is another alternative for bonding of green ceramic tapes. A special liquid agent is screen printed on the green tape, which melts the tape surface. Then the tapes are stacked and compressed at room temperature by a printing roll. The influence of each method on the microchannel geometry is analyzed in this paper. The resulting structures' bonding quality and mechanical properties are examined by a scanning electron microscope (SEM).

  11. Piezoelectric Ceramics and Their Applications

    Science.gov (United States)

    Flinn, I.

    1975-01-01

    Describes the piezoelectric effect in ceramics and presents a quantitative representation of this effect. Explains the processes involved in the manufacture of piezoelectric ceramics, the materials used, and the situations in which they are applied. (GS)

  12. Some metal-graphite and metal-ceramic composites for use as high energy brake lining materials

    Science.gov (United States)

    Bill, R. C.

    1974-01-01

    Materials were studied as candidates for development as potential new aircraft brake lining materials. These families were (1) copper-graphite composites; (2) nickel-graphite composites; (3) copper - rare-earth-oxide (gadolinium oxide (Gd2O3) or lanthanum oxide (La2O3)) composites and copper - rare-earth-oxide (La2O3) - rare-earth-fluoride (lanthanum fluoride (LaF3)) composites; (4) nickel - rare-earth-oxide composites and nickel - rare-earth-oxide - rare-earth-fluoride composites. For comparison purposes, a currently used metal-ceramic composite was also studied. Results showed that the nickel-Gd2O3 and nickel-La2O3-LaF3 composites were comparable or superior in friction and wear performance to the currently used composite and therefore deserve to be considered for further development.

  13. Material Culture and Cultural Meanings: Current Studies of Archaeological Ceramics and in Ce­ramic Ethnoarchaeology

    Directory of Open Access Journals (Sweden)

    Charles C. Kolb

    2000-05-01

    Full Text Available Pottery and People: A Dynamic Interaction. James M. Skibo and Gary M. Feinman (editors. Founda­tions of Archaeological Inquiry. Salt Lake City. University of Utah Press. 1999. 260 pp. 91 figures. 30 tables. ISBN 0-87480-576-7. $55.00 (cloth; 0-87489-577-5. $25.00 (paperback. Material Meanings: Critical Approaches to the Interpretation of Material Culture. Elizabeth S. Chilton (editor. Foundations of Archaeological Inquiry. Salt Lake City: University of Utah Press. 1999.179pp. 35 figures. 11 tables. ISBN 0-87480-632-1. $55.00 (cloth; 087480-633-X. $35.00 (paperback. The description and interpretation of material culture may be regarded as the essence of archaeology, a discipline that seeks to recover, describe, document, and interpret past human culture. More recently, understanding that actions occur in a material world that is constituted symbolically, archaeological explanations are often framed in sociocultural meanings, the analysis of agencies, practices and behaviors. I shall subsequently return to this issue. Because of their longevity in the archaeological record, lithic and ceramic artifacts are crucial to the endeavor to interpret human culture. Objects fashioned from clay and subjected to intentional artificial sources of heat made their initial appearance in the archaeological record more than 26.000 years ago. Ceramic objects have been created in a seemingly endless variety of shapes and forms, varying from fertility figurines. to cooking and food storage vessels. lamps, smoking pipes, medicinal pastilles, tokens, beehives, and coffins to modern whitewares and pyroceramics.

  14. FY 1998 annual report on the study on development of corrosion-resistant ceramic materials for garbage incinerators; 1998 nendo gomi shori shisetsuyo taishoku ceramics zairyo no kaihatsu ni kansuru kenkyu chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Described herein are the FY 1988 results of development of corrosion-resistant ceramic materials for garbage incinerators. Residue released when porcelain stocks are collected is selected as the inexpensive stock for SiO{sub 2}-Al{sub 2}O{sub 3}-based refractory materials. It is incorporated with carbon black and reduced at 1,200 to 1,500 degrees C in a nitrogen atmosphere. Synthesis of the target Si-Al-C-N-O-based compound succeeds in the presence of a solid catalyst, but it is a fine powder, and hence that of the massive compound fails. The commercial ceramic materials and new refractory materials, made on a trial basis, are evaluated for their resistance to corrosion using fry ashes collected from a commercial incinerator. These ashes are higher in melting point, more viscous, holding a larger quantity of attached slag and more corrosive than synthetic ashes. These materials are corroded acceleratedly as temperature increases to 1,200 degrees C or higher, more noted with the ceramic materials than with the refractory materials. Oxidation and melting characteristics of the molten slag affect corrosion of some materials. Use of the graphite-based material shall be limited to a section below the slag surface, where graphite is oxidized to a smaller extent. The MgO-based material is promising. The Al{sub 2}O{sub 3}-Cr{sub 2}O{sub 3}-based material is more promising than any other material developed in this study. Their bending strength before and after the corrosion test is measured at normal temperature to 1,700 degrees C, to investigate their deterioration by high temperature and corrosion. (NEDO)

  15. The Study on the Corelation between TRIZ Theory and Ceramic Material Technology%TRIZ理论与陶瓷材料技术相关性的研究

    Institute of Scientific and Technical Information of China (English)

    贾孝伟; 冯益华; 石鹏辉; 田园

    2015-01-01

    This paper introduces the main content and development process of TRIZ,and analyzes the advantages of TRIZ theory compared with traditional innovative methods,reviews the development status and trends of composite ceramic technology, self-lubricating ceramic materials technology, multilayer ceramic technology and spark plasma sintering process, microwave sintering process, analyzes the relationship between above ceramic material technologies and 40 inventive principles,object-field model, looks to the future research direction combining ceramic materials technology with TRIZ theory.%介绍了TRIZ理论的主要内容及其发展历程。通过与传统的创新方法进行比较,分析了TRIZ理论的优点。综述了陶瓷材料技术中的复合陶瓷材料技术、自润滑陶瓷材料技术、叠层陶瓷材料技术以及放电等离子烧结工艺和微波烧结工艺的发展现状和发展趋势。比较分析了上述工艺技术与TRIZ理论中40条发明原理、物—场模型之间的关系,展望了未来陶瓷材料技术与TRIZ理论相结合研究的发展方向。

  16. Synthesis and analysis of Mo-Si-B based coatings for high temperature oxidation protection of ceramic materials

    Science.gov (United States)

    Ritt, Patrick J.

    The use of Ni-based superalloys in turbine engines has all but been exhausted, with operating temperatures nearing the melting point of these materials. The use of ceramics in turbine engines, particularly ceramic matrix composites such as SiC/C and SiC/SiC, is of interest due to their low density and attractive mechanical properties at elevated temperatures. The same materials are also in consideration for leading edges on hypersonic vehicles. However, SiC-based composites degrade in high temperature environments with low partial pressures of oxygen due to active oxidation, as well as high temperature environments containing water or sand. The need for a protective external coating for SiC-based composites in service is obvious. To date, no coating investigated for SiC/C or SiC/SiC has been proven to be resistant to oxidation and corrosion at intermediate and high temperatures, as well as in environments deficient in oxygen. The Mo-Si-B coating shows great promise in this area, having been proven resistant to attack from oxidation at extreme temperatures, from water vapor and from calcia-magnesia-aluminosilicate (CMAS). The adaptation of the Mo-Si-B coating for ceramic materials is presented in detail here. Evaluation of the coating under a range of oxidation conditions as well as simulated re-entry conditions confirms the efficacy of the Mo-Si-B based coating as protection from catastrophic failure. The key to the oxidation and corrosion resistance is a robust external aluminoborosilica glass layer that forms and flows quickly to cover the substrate, even under the extreme simulated re-entry conditions. Suppression of active oxidation of SiC, which may occur during atmospheric re-entry and hypersonic flight trajectories, has also been examined. In order to adapt the Mo-Si-B based coating to low partial pressures of oxygen and elevated temperatures, controlled amounts of Al were added to the Mo-Si-B based coating. The resulting coating decreased the inward

  17. Recycling of glass fibers from fiberglass polyester waste composite for manufacture glass-ceramic materials

    OpenAIRE

    López Gómez, Félix Antonio; Martín, M. Isabel; García Díaz, Irene; Rodríguez, O.; Alguacil, Francisco José; Romero, M.

    2012-01-01

    This work presents the feasibility of reusing a glass fiber resulting from the thermolysis and gasification of waste composites to obtain glass-ceramic tiles. Polyester fiberglass (PFG) waste was treated at 550˚C for 3 h in a 9.6 dm3 thermolytic reactor. This process yielded an oil (≈24 wt%), a gas (≈8 wt%) and a solid residue (≈68 wt%). After the polymer has been removed, the solid residue is heated in air to oxidize residual char and remove surface contamination. The cleaning fibers were co...

  18. Application of magnetron sputtering for producing bioactive ceramic coatings on implant materials

    Indian Academy of Sciences (India)

    J Z Shi; C Z Chen; H J Yu; S J Zhang

    2008-11-01

    Radio frequency (RF) magnetron sputtering is a versatile deposition technique that can produce thin, uniform, dense calcium phosphate coatings. In this paper, principle and character of magnetron sputtering is introduced, and development of the hydroxyapatite and its composite coatings application is reviewed. In addition, influence of heat treatment on magnetron sputtered coatings is discussed. The heat treated coatings have been shown to exhibit bioactive behaviour both in vivo and in vitro. At last, the future application of the bioactive ceramic coating deposited by magnetron sputtering is mentioned.

  19. Studying the sintering behavior of BeOx-SiC1-x Composite ceramic Material

    Science.gov (United States)

    Issa, Tarik Talib

    2011-12-01

    The sintering behavior for BeO-SiC compacts composite ceramic at different sintering temperatures in air were conducted, resulting data indicated that the percentage of SiC (Wt% 5) sintered at 800 C° lead to higher sintering density of (1.80 gm/cm3). The x-ray diffraction pattern analysis indicated nothing change concerning the crystal structure. Microstructure development has been studied as a function SiC content. Silicon carbide found to be suppressed the sinter ability of the matrix BeO powder.

  20. Industrial ceramics

    International Nuclear Information System (INIS)

    After having given the definition of the term 'ceramics', the author describes the different manufacturing processes of these compounds. These materials are particularly used in the fields of 1)petroleum industry (in primary and secondary reforming units, in carbon black reactors and ethylene furnaces). 2)nuclear industry (for instance UO2 and PuO2 as fuels; SiC for encapsulation; boron carbides for control systems..)

  1. 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.

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

    International Nuclear Information System (INIS)

    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

  3. Effect of surface treatment and liner material on the adhesion between veneering ceramic and zirconia.

    Science.gov (United States)

    Yoon, Hyung-in; Yeo, In-sung; Yi, Yang-jin; Kim, Sung-hun; Lee, Jai-bong; Han, Jung-suk

    2014-12-01

    Fully sintered zirconia blocks, each with one polished surface, were treated with one of the followings: 1) no treatment, 2) airborne-particle abrasion with 50μm alumina, and 3) airborne-particle abrasion with 125μm alumina. Before veneering with glass ceramic, either liner Α or liner B were applied on the treated surfaces. All veneered blocks were subjected to shear force in a universal testing machine. For the groups with liner A, irrespective of the particle size, air abrasion on Y-TZP surfaces provided greater bond strength than polishing. Application of liner B on an abraded zirconia surface yielded no significant influence on the adhesion. In addition, specimens with liner A showed higher bond strength than those with liner B, if applied on roughened surfaces. Fractured surfaces were observed as mixed patterns in all groups. For the liner A, surface treatment was helpful in bonding with veneering ceramic, while it was ineffective for the liner B. PMID:25282467

  4. 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.

  5. Studies on development of new functional natural materials from agricultural products - Technology developments for ceramic powders and materials from rice phytoliths

    International Nuclear Information System (INIS)

    Based on an estimation of annual rice production of 5.2 million tons, rice husks by-production reaches to 1.17 million tons per year in Korea. Distinguished to other corns, rice contains a lot of Si; 10-20% by weight in rice husks calculated as silica. The aim of this research project is to develop technologies for ceramic powders and materials utilizing the silica in rice husks called phytoliths. In this first year research, researches of the following subjects were performed; material properties of rice husks, milling of rice husks, acid treatments, oxidations at low and high temperatures, sintering and crystalization of amorphous silica, low temperature carburization, formation of silicon carbide whiskers, and brick lightening method using milled rice husks. 11 tabs., 49 figs., 75 refs. (Author)

  6. Studies on development of new functional natural materials from agricultural products - Technology developments for ceramic powders and materials from rice phytoliths

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dae Kap; Kim, Yong Ik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Yoon, Nang Kyu; Seong, Seo Yong [Myongseong Ceramics Com., Taejon (Korea, Republic of); Ryu, Sang Eun [Bae Jae Univ., Taejon (Korea, Republic of); Lee, Jae Chun [Myungji Univ., Seoul (Korea, Republic of)

    1995-08-01

    Based on an estimation of annual rice production of 5.2 million tons, rice husks by-production reaches to 1.17 million tons per year in Korea. Distinguished to other corns, rice contains a lot of Si; 10-20% by weight in rice husks calculated as silica. The aim of this research project is to develop technologies for ceramic powders and materials utilizing the silica in rice husks called phytoliths. In this first year research, researches of the following subjects were performed; material properties of rice husks, milling of rice husks, acid treatments, oxidations at low and high temperatures, sintering and crystalization of amorphous silica, low temperature carburization, formation of silicon carbide whiskers, and brick lightening method using milled rice husks. 11 tabs., 49 figs., 75 refs. (Author).

  7. Recent development of ceria-based (nano)composite materials for low temperature ceramic fuel cells and electrolyte-free fuel cells

    OpenAIRE

    Fan, Liangdong; Wang, Chengyang; Chen, Mingming; Zhu, Bin

    2013-01-01

    In the last ten years, the research of solid oxide fuel cells (SOFCs) or ceramic fuel cells (CFC) had focused on reducing the working temperature through the development of novel materials, especially the high ionic conductive electrolyte materials. Many progresses on single-phase electrolyte materials with the enhanced ionic conductivity have been made, but they are still far from the criteria of commercialization. The studies of ceria oxide based composite electrolytes give an alternative s...

  8. Ceramic Technology Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

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

  9. Potentiality of a frit waste from ceramic sector as raw material to glass-ceramic material production; Potencialidad de un residuo de frita procedente del sector ceramico como materia prima para la produccion de material vitroceramico

    Energy Technology Data Exchange (ETDEWEB)

    Barrachina Albert, E.; Llop Pla, J.; Notari Abad, M. D.; Carda Castello, J. B.

    2015-10-01

    This work consists of studying the devitrification capacity of a residue from sodium-calcium frit, using the vitreous powder sintering method, which follows the traditional ceramic processing route, including a specific heat treatment to generate the appearance of crystals from the original glass phase. Initially the frit residue has been characterized by instrumental techniques such as XRF, XRD and DTA/TG. Furthermore, the chemical analysis (XRF) has allowed the prediction of devitrification potentiality of this residue by theoretical approaches represented by Gingsberg, Raschin-Tschetverikov and Lebedeva ternary diagrams. Then, this residue was subjected to traditional ceramic method, by changing the grinding time, the pressing pressure and prepared samples were obtained at different temperatures. In this part, the techniques for measuring particle size by laser diffraction and XRD and SEM to evaluate the generated crystalline phases, were applied. Finally, it has been found that this frit residue works as glass-ceramic precursor, devitrifying in wollastonite crystals as majority phase and without being subjected to the melting step of the glass-ceramic typical method. (Author)

  10. Microstructural investigations of materials for low temperature co-fired ceramic (LTCC) based fuel cell using small angle neutron scattering

    International Nuclear Information System (INIS)

    The concept and the realization fuel cell based on LTCC technology require the investigations of fired LTCC microstructures. The majority of the works involved using small angle neutron scattering studies on the microstructural of LTCC ceramic tape and development of neutron tomography for future tool to visualize channels inside the fired tape. Most SANS characterization were carried out at Smarter SANS instrument at BATAN, Indonesia. Standard sample for resolving tens of micron of object size were measured using simple neutron tomography setup utilizing monochromatic SANS beam at Malaysian Nuclear Agency. The initial microstructural findings indicates that organic additives shape the final microstructural of LTCC after firing with the glassy material possibly fill the space left by the burned organic additives. The tomography results showed that 40 micron size object can be differentiated. The conductor deposited on LTCC is preliminary investigated which will later be used as support for catalyst.

  11. Rolling-element fatigue life of silicon nitride balls. [as compared to that of steel, ceramic, and cermet materials

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.

    1974-01-01

    The five-ball fatigue tester was used to evaluate silicon nitride as a rolling-element bearing material. Results indicate that hot-pressed silicon nitride running against steel may be expected to yield fatigue lives comparable to or greater than those of bearing quality steel running against steel at stress levels typical rolling-element bearing application. The fatigue life of hot-pressed silicon nitride is considerably greater than that of any ceramic or cermet tested. Computer analysis indicates that there is no improvement in the lives of 120-mm-bore angular--contact ball bearings of the same geometry operating at DN values from 2 to 4 million where hot-pressed silicon nitride balls are used in place of steel balls.

  12. Nanopartículas catalisadoras suportadas por materiais cerâmicos Catalytic nanoparticles supported by ceramic materials

    Directory of Open Access Journals (Sweden)

    N. L. V. Carreño

    2002-09-01

    Full Text Available Neste trabalho são apresentados os procedimentos de preparação de materiais cerâmicos de SiO2, SnO2 e Al2O3 e, também, suas propriedades catalíticas nas reações de reforma do metano e do metanol. As análises dos resíduos de carbono, após testes catalíticos, sugerem que a modificação estrutural dos catalisadores pode minimizar os efeitos de sua desativação.This work presents the procedures for preparing SiO2, SnO2 and Al2O3 ceramic materials and also their catalytic properties for the reforming reactions of methane and methanol. The analyses of the carbonaceous residues suggest that the structural modification of the catalyst can minimize the deactivation effect upon them.

  13. Ceramic Carbon/Polypyrrole Materials for the Construction of Bienzymatic Amperometric Biosensor for Glucose

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel amperometric glucose biosensor was constructed by electrochemical formation of a polypyrrole (PPy) membrane in the presence of glucose oxidase (GOD) on the surface of a horseradish peroxidase (HRP) modified ferrocenecarboxylic acid (FCA) mediated sol-gel derived ceramic carbon electrode. The amperometric detection of glucose was carried out at +0.16 V (vs. SCE) in 0.1 mol/L phosphate buffer solution (pH 6.9) with a linear response range between 8.0×10-5 and 1.3×10-3 mol/L of glucose. The biosensor showed a good suppression of inter- ference and a negligible deviation in the amperometric detection.

  14. Ceramic material life prediction: A program to translate ANSYS results to CARES/LIFE reliability analysis

    Science.gov (United States)

    Vonhermann, Pieter; Pintz, Adam

    1994-01-01

    This manual describes the use of the ANSCARES program to prepare a neutral file of FEM stress results taken from ANSYS Release 5.0, in the format needed by CARES/LIFE ceramics reliability program. It is intended for use by experienced users of ANSYS and CARES. Knowledge of compiling and linking FORTRAN programs is also required. Maximum use is made of existing routines (from other CARES interface programs and ANSYS routines) to extract the finite element results and prepare the neutral file for input to the reliability analysis. FORTRAN and machine language routines as described are used to read the ANSYS results file. Sub-element stresses are computed and written to a neutral file using FORTRAN subroutines which are nearly identical to those used in the NASCARES (MSC/NASTRAN to CARES) interface.

  15. Development of New Ecological Ceramic Tiles by Recycling of Waste Glass and Ceramic Materials; Incorporacion de residuos derivados de la fabricacion ceramica y del vidrio reciclado en el proceso ceramico integral

    Energy Technology Data Exchange (ETDEWEB)

    Lazaro, C.; Ramon Trilles, V.; Gomez, F.; Allepuz, S.; Fraga, D.; Carda, J. B.

    2012-07-01

    The following research work shows the results of the introduction of waste generated by the ceramic industry, such as the calcined clay from fired porcelain of stoneware and raw biscuit, sludge and cleaning water, as well as waste from other sectors like the recycling glass. In this way, it can be obtained a stoneware porcelain slab, engobe-glaze and satin glaze that contains high percentage of recyclable raw materials. (Author)

  16. Defect production in ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J. [Oak Ridge National Lab., TN (United States); Kinoshita, C. [Kyushu Univ. (Japan)

    1997-08-01

    A review is given of several important defect production and accumulation parameters for irradiated ceramics. Materials covered in this review include alumina, magnesia, spinel silicon carbide, silicon nitride, aluminum nitride and diamond. Whereas threshold displacement energies for many ceramics are known within a reasonable level of uncertainty (with notable exceptions being AIN and Si{sub 3}N{sub 4}), relatively little information exists on the equally important parameters of surviving defect fraction (defect production efficiency) and point defect migration energies for most ceramics. Very little fundamental displacement damage information is available for nitride ceramics. The role of subthreshold irradiation on defect migration and microstructural evolution is also briefly discussed.

  17. Defect production in ceramics

    International Nuclear Information System (INIS)

    A review is given of several important defect production and accumulation parameters for irradiated ceramics. Materials covered in this review include alumina, magnesia, spinel silicon carbide, silicon nitride, aluminum nitride and diamond. Whereas threshold displacement energies for many ceramics are known within a reasonable level of uncertainty (with notable exceptions being AIN and Si3N4), relatively little information exists on the equally important parameters of surviving defect fraction (defect production efficiency) and point defect migration energies for most ceramics. Very little fundamental displacement damage information is available for nitride ceramics. The role of subthreshold irradiation on defect migration and microstructural evolution is also briefly discussed

  18. Defect production in ceramics

    International Nuclear Information System (INIS)

    A review is given of several important defect production and accumulation parameters for irradiated ceramics. Materials covered in this review include alumina, magnesia, spinel, silicon carbide, silicon nitride, aluminum nitride and diamond. Whereas threshold displacement energies for many ceramics are known within a reasonable level of uncertainty (with notable exceptions being AlN and Si3N4), relatively little information exists on the equally important parameters of surviving defect fraction (defect production efficiency) and point defect migration energies for most ceramics. Very little fundamental displacement damage information is available for nitride ceramics. The role of subthreshold irradiation on defect migration and microstructural evolution is also briefly discussed. (orig.)

  19. Use of new raw materials and industrial wastes to improve the possibilities of using ceramic materials from Bailén (Jaén, southern Spain

    Directory of Open Access Journals (Sweden)

    Galán-Arboledas, R. J.

    2013-12-01

    Full Text Available Raw materials used by the ceramic industry in Jaén (southern Spain consist of mixtures of carbonated clays from the Guadalquivir Basin and red clays from the Iberian Massif. The mixtures formulation usually obeys empirical experience developed by this industry for many generations. This work evaluates different possibilities of using these raw materials to manufacture new ceramic products on the basis of clay physical-chemical properties and analyzes limitations to produce high added value products. As an alternative to overcome these limitations, the mixture of these clays with raw materials from near regions (pyrophyllite clay and with different industrial wastes is proposed. These wastes are screen glass from monitors and oil impregnated diatomaceous earth. The study of the technological properties shows that the new mixtures are suitable for the processing of ceramic products in which structural and thermal insulating properties are improved or kept.La materia prima empleada por la industria cerámica de Jaén consiste en mezclas de margas de la Depresión del Guadalquivir con arcillas rojas del Macizo Ibérico. La formulación de estas mezclas responde generalmente a la experiencia empírica desarrollada por esta industria durante generaciones. El presente trabajo evalúa las posibilidades de utilización de estas materias primas para fabricar nuevos productos cerámicos de construcción basándose en sus propiedades físico-químicas y analiza las limitaciones que presentan para la fabricación de productos de mayor valor añadido. Como alternativa para superar estas limitaciones se propone la mezcla con arcillas pirofilíticas de áreas geográficamente cercanas y con diferentes residuos industriales. Estos residuos son vidrio de pantalla descontaminado y tierras diatomeas impregnadas con aceites vegetales. El estudio de caracterización tecnológica muestra que las nuevas mezclas permiten el procesamiento de piezas cerámicas y que en

  20. Authenticity and origin of prehispanic ceramic material, analysis of zapotecan urns of the Ontario Real Museum

    International Nuclear Information System (INIS)

    The Zapotec culture flourished approximately in Oaxaca of the year 220 B.C. up to the 800 D.C., in their funeral acts the Zapotec often took to the tomb to their deads accompanied of rich offerings including a great variety of ceramic, one of these varieties of ceramics were those urns that are kind of an adorned vessels with a sphinx, that is to say, a cylinder that has incorporate a figure generally anthropomorphous, which represented ancestres or divinities, the size of these urns went from the 15 cm until but of a meter high. At the beginning of the XX century the urns got the attention of the collectors and a number important of replies (false) they were manufactured copying the original ones, in this time C. Rickards gathers one of those but important collections of urns zapotec, in 1919 the Real Museum of Ontario (ROM) acquired the collection Rickards, in the 70 s they were practiced test of authenticity for thermoluminescence indicating that 36 of these urns were false, comparing their iconography with the other urns of the collection suggests the possibility that at least 80 of these pieces are not you authenticate. In this work the results are presented by thermoluminescence carried out to 17 pieces of the collection Rickards property of the Real Museum of Ontario like part of a first one work stage, for they were perforated it the urns with a drill of tungsten carbide extracting 50 milligrams approximately, of which 25 were used for thermoluminescence and the rest for analysis for X ray Emission Spectroscopy. Proton Induced X-ray Emission (PIXE) and for X-ray Diffraction (XRD). The test of authenticity for thermoluminescence beginning with the determination of the rate of annual dose starting from the determination of the concentration of the natural radioisotopes of uranium (238 U) and torio (232 Th) by means of an accountant of particles alpha, the potassium (40 K) by means of X-ray diffraction, later on the sample was treated chemically with hydrogen

  1. Crystal structure, electron-density distribution and ion-diffusion pathway of ceramic materials investigated by multiple approaches including neutron and X-ray diffraction methods

    International Nuclear Information System (INIS)

    Crystal structure is the fundamental information in the materials science, chemistry, physics and geoscience. Electron-density distribution of ceramic materials is important, because most of material properties are governed by the electronic states. Ion-diffusion pathway is useful to understand the ion conduction mechanism. In the present paper the author briefly reviews his group's recent research works on the crystal structure, thermal expansion, electron-density distribution and ion-diffusion pathway of some ceramic materials investigated by multiple approaches such as synchrotron X-ray powder diffraction, neutron powder diffraction, electron diffraction, first-principles electronic calculations, maximum-entropy method (MEM) and bond valence method. The crystal structure should be examined by multiple methods, because invalid structure sometimes gives good Rietveld fit. (author)

  2. A comparison of the wear resistance and hardness of two different indirect composite resins with a ceramic material, opposed to human enamel

    OpenAIRE

    Ahmet Kursad Culhaoglu; Joonge Park

    2013-01-01

    Objectives: The aim of this study was to compare the two-body wear resistance of two different indirect composites and lithium disilicate porcelain versus human enamel antagonists. Materials and Methods: Ten specimens of each material (BelleGlass NG, Kerr Corp.; SR Adoro, Ivoclar Vivadent AG; IPS e.max, Ivoclar Vivadent AG) were fabricated. Indirect dental composites and all-ceramic restoration were compared by an in vitro tribological test against human teeth antagonist. Wear loss of antagon...

  3. Thermocouple and controlling cables of electric penetrations for nuclear power stations. hermetization with glass-ceramic and glass-fiber materials

    International Nuclear Information System (INIS)

    New perspective technology for hermetization of cable ends for fabrication of hermetical inlets for NPPs with inorganic materials is developed. On the basis of the studies dielectric inorganic materials, resistive to γ-radiation and fire, are selected for creation of hermetically sealed inlets. Principally new methods for fabrication of hermoinlets is developed on the basis of metallic modules with fibre circuitously and ceramic hermetization units

  4. Sintered gahnite–cordierite glass-ceramic based on raw materials with different fluorine sources

    Indian Academy of Sciences (India)

    Esmat M A Hamzawy; Mohammed A Bin Hussain

    2015-12-01

    Glass-ceramic based on Zn-containing cordierite was prepared from kaolin, silica'sand and commercial ZnO. The addition of AlF3, MgF2 and CaF2 was performed as nucleation catalysts. Dark brown glasses were obtained from the glass batches. The transformation and crystallization temperatures were in the range of 739–773 and 972–1007°C, respectively. Gahnite, cordierite and very little enstatite were the development crystalline phases through the heating and sintering process between 1000 and 1340°C. The microstructure of crystallized samples at 1340°C showed the appearance of dominant euhedral octahedral crystals of gahnite and hexagonal cordierite, in the low micro-scale, disseminated in the glassy matrix. The microanalysis of the crystallized samples indicated that Zn and Mg may replace each other in gahnite and cordierite structure. Densities of the crystallized samples were between 2.2517 and 2.5278 g cm−3. The thermal expansion of the crystallized samples was ranging from 19.22 to 59.30 × 10−7°C−1. However, the higher crystallization of both cordierite and gahnite accompany with the higher values of densities and the lower values of coefficient of thermal expansion.

  5. RESEARCH STATUS OF SELF- LUBRICATION OF CERAMIC AND CERAMIC COMPOSITE MATERIALS AT HIGH TEMPERATURES%陶瓷及其复合材料高温自润滑的研究现状

    Institute of Scientific and Technical Information of China (English)

    陈晓虎

    2001-01-01

    The research status of self- lubricating ceramic composite materials and self- lubrication of structural ceramics are briefly introduced in this paper. The effect of solid lubricant characteristics, the properties of interface and the effect of tribochemical reaction films are also discussed upon the efficiency of self- lubrication. The current insufficiency about the research of selflubricating ceramic composite materials is summarized and the possible problems are pointed out for the following study.%本文就固态润滑组元性质、与陶瓷基体界面特性以及摩擦化学反应膜层等几方面因素对陶瓷自润滑效应的影响,简要介绍了当前自润滑金属陶瓷材料、自润滑陶瓷复合材料和结构陶瓷自身润滑功效的一些研究情况。总结了自润滑陶瓷材料研究中存在的不足,并提出了今后研究应注意的问题。

  6. Thermodynamic analysis of chemical compatibility of ceramic reinforcement materials with niobium aluminides

    Science.gov (United States)

    Misra, Ajay K.

    1990-01-01

    Chemical compatibility of several reinforcement materials with three niobium aluminides, Nb3Al, Nb2Al, and NbAl3, were examined from thermodynamic considerations. The reinforcement materials considered in this study include carbides, borides, nitrides, oxides, silicides, and Engel-Brewer compounds. Thermodynamics of the Nb-Al system were reviewed and activities of Nb and Al were derived at desired calculation temperatures. Criteria for chemical compatibility between the reinforcement material and Nb-Al compounds have been defined and several chemically compatible reinforcement materials have been identified.

  7. Transparent Yb:YAG ceramics

    OpenAIRE

    Hostasa, Jan; Esposito, Laura; Piancastelli, Andreana

    2011-01-01

    YAG ceramics doped with rare earth elements have been recently given a consistent attention as materials for various applications. The specific application depends on the doping element added. Addition of Yb is used for the production of active materials for solid state lasers, and YAG polycrystalline ceramics are promising materials for the replacement of single crystals, which are mostly used at present. The advantage of polycrystalline ceramics over single crystals are the lower fabricatio...

  8. Moessbauer studies of raw materials from Misti volcano of Arequipa (Peru) for its potential application in the ceramic field

    Energy Technology Data Exchange (ETDEWEB)

    Bustamante, Angel, E-mail: angelbd1@gmail.com [Universidad Nacional Mayor de San Marcos (Peru); Capel, Francisco; Barba, Flora, E-mail: flora@icv.csic.es; Callejas, Pio [Consejo Superior de investigaciones Cientificas (CSIC), Instituto de Ceramica y Vidrio (Spain); Guzman, Rivalino [Universidad Nacional de San Agustin de Arequipa (Peru); Trujillo, Alejandro [Universidad Nacional Mayor de San Marcos (Peru)

    2009-04-15

    We would like to introduce, the study of two different colour 'sillar' samples: white and pink, belonging to the Anashuayco quarry in the Arequipa Region (Peru). The X-ray diffraction (XRD) analysis indicates the presence of several mineralogical phases, such as feldpars and biotite for the both white and pink 'sillar' whereas cristobalite and quartz are detected only in the first sample and amorphous phase in the second one. In room temperature, Moessbauer spectroscopy, the presence of hematite ({alpha}-Fe{sub 2}O{sub 3}) was detected as the main phase for both samples, this was not detected in the XRD measurements. Moreover, corresponding doublets in the Moessbauer spectra indicate the presence of iron in the aluminium-silicate minerals. The rates Fe{sup 2+}/Fe{sup 3+} are 0.0752 and 0.0526 to the white and pink samples respectively. The minerals composing the white tuff form a heterogeneous aggregate of uniform aspect. Mining of these materials generates a great amount of waste in the form of lumps of varying size and which are raw materials studied in the present work for potential application in the ceramic field.

  9. Moessbauer studies of raw materials from Misti volcano of Arequipa (Peru) for its potential application in the ceramic field

    International Nuclear Information System (INIS)

    We would like to introduce, the study of two different colour 'sillar' samples: white and pink, belonging to the Anashuayco quarry in the Arequipa Region (Peru). The X-ray diffraction (XRD) analysis indicates the presence of several mineralogical phases, such as feldpars and biotite for the both white and pink 'sillar' whereas cristobalite and quartz are detected only in the first sample and amorphous phase in the second one. In room temperature, Moessbauer spectroscopy, the presence of hematite (α-Fe2O3) was detected as the main phase for both samples, this was not detected in the XRD measurements. Moreover, corresponding doublets in the Moessbauer spectra indicate the presence of iron in the aluminium-silicate minerals. The rates Fe2+/Fe3+ are 0.0752 and 0.0526 to the white and pink samples respectively. The minerals composing the white tuff form a heterogeneous aggregate of uniform aspect. Mining of these materials generates a great amount of waste in the form of lumps of varying size and which are raw materials studied in the present work for potential application in the ceramic field.

  10. 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.

  11. Effects of different surface finishing procedures on the change in surface roughness and color of a polymer infiltrated ceramic network material

    Science.gov (United States)

    Arslan, Merve; Türker, Nurullah; Barutcigil, Kubilay

    2016-01-01

    PURPOSE Polymer infiltrated ceramic network (PICN) materials, also called hybrid ceramics, are new materials in dental market. The manufacturer of the PICN material VITA Enamic suggests 3 different finishing procedures for this new material. In the present study, surface roughness and color differences caused from different finishing procedures of VITA Enamic were investigated. MATERIALS AND METHODS 120 specimens were prepared in dimensions 2 × 10 × 12 mm from VITA Enamic hybrid ceramic blocks with 'high translucency' and 'translucency 2M2' shades. The specimens were divided into 8 groups. For each group, different finishing procedures suggested by the manufacturer were performed. Surface roughness values were determined by a tactile portable profilometer. Color changes were evaluated using a clinical spectrophotometer. The data were analyzed using one-way ANOVA and Tukey's post-hoc comparison. The significance level was set at α=0.05. RESULTS The roughest surfaces were observed in Glaze Groups. Their surface roughness values were similar to that of the control group. Clinical Kit and Technical Kit groups did not show a statistically significant difference regarding surface roughness (P>.05). The largest color difference regarding ΔE00 was observed in Clinical Kit finishing groups. There were also statistically significant color changes between the groups (P2.25). CONCLUSION Within the limitations of the present study, it may be suggested that finishing the VITA Enamic restorations by Technical Kit instead of Glaze and Clinical Kit gives better clinical performance in regard to surface roughness and shade matching. PMID:26949483

  12. Molybdate Based Ceramic Negative-Electrode Materials for Solid Oxide Cells

    DEFF Research Database (Denmark)

    Graves, Christopher R.; Reddy Sudireddy, Bhaskar; Mogensen, Mogens Bjerg

    2010-01-01

    Novel molybdate materials with varying Mo valence were synthesized as possible negative-electrode materials for solid oxide cells. The phase, stability, microstructure and electrical conductivity were characterized. The electrochemical activity for H2O and CO2 reduction and H2 and CO oxidation was...... enhanced the electrocatalytic activity and electronic conductivity. The polarization resistances of the best molybdates were two orders of magnitude lower than that of donor-doped strontium titanates. Many of the molybdate materials were significantly activated by cathodic polarization, and they exhibited...

  13. Monolithic ceramics

    Science.gov (United States)

    Herbell, Thomas P.; Sanders, William A.

    1992-01-01

    A development history and current development status evaluation are presented for SiC and Si3N4 monolithic ceramics. In the absence of widely sought improvements in these materials' toughness, and associated reliability in structural applications, uses will remain restricted to components in noncritical, nonman-rated aerospace applications such as cruise missile and drone gas turbine engine components. In such high temperature engine-section components, projected costs lie below those associated with superalloy-based short-life/expendable engines. Advancements are required in processing technology for the sake of fewer and smaller microstructural flaws.

  14. Ceramic composition

    International Nuclear Information System (INIS)

    Improved ceramic compositions useful for cutting tools and the like are described. They are composed of an essentially homogeneous admixture of sintered powders of an aluminum oxide base material with other refractories including zirconium oxide, titanium oxide, hafnium oxide, titanium nitride, zirconium nitride, and tungsten or molybdenum carbide. In addition to their common and improved properties of hardness and strength, many of these compositions may be made by simple cold-pressing and sintering procedures. This avoids the known drawbacks of conventional hot press production

  15. Advances in materials science, metals and ceramics division. Triannual progress report, June-September 1980

    International Nuclear Information System (INIS)

    Information is presented concerning the magnetic fusion energy program; the laser fusion energy program; geothermal research; nuclear waste management; Office of Basic Energy Sciences (OBES) research; diffusion in silicate minerals; chemistry research resources; and chemistry and materials science research

  16. Production of nuclear fusion reactor fuel by ceramic tritium breeder material

    International Nuclear Information System (INIS)

    Fuel tritium is generated from the nuclear reaction between the fusion neutron and the lithium of the breeder material arranged in the blanket that encloses the fusion plasma in the fusion reactor. However, the release process of the generated tritium has not been completely clarified. Recently, Japan Atomic Energy Agency started the tritium generation and recovery experiment in using nuclear fusion neutron source (FNS). In this report, the recent results of study on breeder material and its manufacturing technology is presented. (author)

  17. Selection and application of oral all-ceramic crown materials%口腔全瓷冠修复材料的选择及应用

    Institute of Scientific and Technical Information of China (English)

    程谨春

    2011-01-01

    BACKGROUND: Compared with porcelain fused to metal crown, the all-ceramic crown materials have been more and more applied in clinical anterior teeth restoration due to natural and stable color, low thermal conductivity, non-electric conductivity, wear resistance, good biocompatibility, non-transparent metallic, and relatively simple operations.OBJECTIVE: To summarize the characteristics, production methods and clinical application of different all-ceramic crown materials.METHODS: A computer-based online retrieval was performed in Wanfang database and Medline database between 2001 and 2011 for articles regarding the characteristics, production methods, physical and mechanical strength, chemical and biological compatibility, aesthetic appearance and clinical application of different all-ceramic crown materials.RESULTS AND CONCLUSION: Currently, the clinically used all-ceramic materials can be divided into slip casting porcelain,casting ceramic, heat-pressed glass ceramic, glass-infiltrated ceramics, densely-sintered aluminum oxide polycrystalline, partially stabilized tetragonal zirconium oxide polycrystalline, and nano-composite ceramic. Different materials have its specific mechanical properties and clinical indications, so clinical selection must be based on specific conditions. With the advance of high-strength ceramic studies, all-ceramic restorations become widely applied, and high-aluminum ceramic represented by In-ceram and zirconia all-ceramic crowns can achieve good effects within a short and long term, foreign clinical experiments have conducted the enlargement from anterior crown to rear crown and bridge. To insure optimum long-term clinical results of all-ceramic crown restorations, the key is to overcome the fragmentation of dental prosthesis, mainly through modifying the composition, improving the anti -smash property of ceramic materials, and a series of prevention measures.%背景:相对于金属烤瓷冠而言,全瓷冠具有色泽稳定自然,导

  18. Glass-ceramic materials of system MgO-Al2O3-SiO2 from rice husk ash

    International Nuclear Information System (INIS)

    This wok shows the results of a valorisation study to use rice husk ash as raw material to develop glass-ceramic materials. An original glass has been formulated in the base system MgO-Al2O3-SiO2 with addition of B2O3 and Na2O to facilitate the melting and poring processes. Glass characterization was carried out by determining its chemical composition. Sintering behaviour has been examined by Hot Stage Microscopy (HSM). Thermal stability and crystallization mechanism have been studied by Differential Thermal Analysis (DTA). Mineralogy analyses of the glass-ceramic materials were carried out using X-ray Diffraction (XRD). Results show that it is possible to use ash rice husk to produce glass-ceramic materials by a sintercrystallization process, with nepheline (Na2OxAl2O3xSiO2) as major crystalline phase in the temperature interval 700-950 degree centigrade and forsterite (2MgOxSiO2) at temperatures above 950 degree centigrade. (Author) 15 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kupp, E.R.; Trubelja, M.F.; Spear, K.E.; Tressler, R.E. [Pennsylvania State Univ., University Park, PA (United States)

    1995-08-01

    Experimental corrosion studies of hot gas filter materials and heat exchanger materials in oxidizing combustion environments have been initiated. Filter materials from 3M Co. and DuPont Lanxide Composites Inc. are being tested over a range of temperatures, times and gas flows. It has been demonstrated that morphological and phase changes due to corrosive effects occur after exposure of the 3M material to a combustion environment for as little as 25 hours at 800{degrees}C. The study of heat exchanger materials has focused on enhancing the corrosion resistance of DuPont Lanxide Dimox{trademark} composite tubes by adding chromium to its surfaces by (1) heat treatments in a Cr{sub 2}O{sub 3} powder bed, or (2) infiltrating surface porosity with molten chromium nitrate. Each process is followed by a surface homogenization at 1500{degrees}C. The powder bed method has been most successful, producing continuous Cr-rich layers with thicknesses ranging from 20 to 250 {mu}m. As-received and Cr-modified DuPont Lanxide Dimox{trademark} samples will be reacted with commonly encountered coal-ash slags to determine the Cr effects on corrosion resistance.

  20. Antibacterial ceramic for sandbox. Sunabayo kokin ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, K. (Ishizuka Glass Co. Ltd. Nagoya (Japan))

    1993-10-01

    Sands in sandboxes in parks have been called into question of being contaminated by colon bacilli and spawns from ascarides. This paper introduces an antibacterial ceramic for sandbox developed as a new material effective to help reduce the contamination. The ceramic uses natural sand as the main raw material, which is added with borax and silver to contain silver ions that have bacteria and fungus resistance and deodorizing effect. The ceramic has an average grain size ranging from 0.5 mm to 0.7 mm, and is so devised as to match specific gravity, grain size and shape of the sand, hence no separation and segregation can occur. The result of weatherability and antibacterial strength tests on sand for a sandbox mixed with the ceramic at 1% suggests that its efficacy lasts for about three years. Its actual use is under observation. Its efficacy has been verified in a test that measures a survival factor of spawns from dog ascardides contacted with aqueous solution containing the ceramic at 1%. Safety and sanitation tests have proved the ceramic a highly safe product that conforms to the food sanitation law. 5 refs., 3 figs., 3 tabs.

  1. Ceramic tube materials and processing development. Topical report, February 1982-December 1984

    Energy Technology Data Exchange (ETDEWEB)

    Green, K.E.; Rivkin, M.I.; Roy, D.W.

    1985-07-01

    A cost-effective material/process has been developed for fabrication of SiC tubes that satisfy many of the structural and operating environment requirements for high-temperature heat recovery systems. Available property data plus cost projects are presented. Accomplishments and results include: Extensive search for and final selection of lowest-cost starting materials commercially available at the time; Development of appropriate body formulations and processes to successfully utilize the respective low-cost raw materials selection; Development of an extrusion process (including tool design) to successfully fabricate and dry tubing; Development of an optimal firing (siliconizing) cycle to adequately infiltrate the extruded tubes so they would yield measured properties which would meet or exceed the agreed upon specifications set down in concert with systems designers; A final standardized process that should yield acceptable reaction bonded SiC tubing well within the target pricing in large quantities.

  2. Tribological behaviour of Si3N4–BN ceramic materials for dry sliding applications

    OpenAIRE

    Carrapichano, J. M.; Gomes, J. R.; Silva, R F

    2002-01-01

    The main objective of this paper is to help on the clarification of the lack of consensus in the bibliographic data concerning the tribological behaviour of Si3N4–BN omposites. Unlubricated sliding tests by pin-on-disc were carried out with three grades of composite materials with 10, 18 and 25 vol.% of BN. The addition of BN to the Si3N4 matrix resulted in a slight reduction of the friction coefficient, which decreased from 0.82 for monolithic Si3N4 to 0.67 for Si3N4–10%BN materials. Wear co...

  3. Examination of the material removal mechanisms during the lapping process of advanced ceramic rolling elements

    OpenAIRE

    Kang, J.; Hadfield, M

    2005-01-01

    Two types of HIPed Si3N4 bearing ball blanks with different surface hardness and fracture toughness were lapped under various loads, speeds, and lubricants using a novel eccentric lapping machine. The lapped surfaces were examined by optical microscope and SEM. The experimental results show that the material removal rate for type I ball blanks were 3-4-fold of type 2 in most cases. Different lapping fluids affected the material removal rate at lower lapping loads, but they had much less influ...

  4. Fused deposition of ceramics: A comprehensive experimental, analytical and computational study of material behavior, fabrication process and equipment design

    Science.gov (United States)

    Bellini, Anna

    Customer-driven product customization and continued demand for cost and time savings have generated a renewed interest in agile manufacturing based on improvements on Rapid Prototyping (RP) technologies. The advantages of RP technologies are: (1) ability to shorten the product design and development time, (2) suitability for automation and decrease in the level of human intervention, (3) ability to build many geometrically complex shapes. A shift from "prototyping" to "manufacturing" necessitates the following improvements: (1) Flexibility in choice of materials; (2) Part integrity and built-in characteristics to meet performance requirements; (3) Dimensional stability and tolerances; (4) Improved surface finish. A project funded by ONR has been undertaken to develop an agile manufacturing technology for fabrication of ceramic and multi-component parts to meet various needs of the Navy, such as transducers, etc. The project is based on adaptation of a layered manufacturing concept since the program required that the new technology be developed based on a commercially available RP technology. Among various RP technologies available today, Fused Deposition Modeling (FDM) has been identified as the focus of this research because of its potential versatility in the choice of materials and deposition configuration. This innovative approach allows for designing and implementing highly complex internal architectures into parts through deposition of different materials in a variety of configurations in such a way that the finished product exhibit characteristics to meet the performance requirements. This implies that, in principle, one can tailor-make the assemble of materials and structures as per specifications of an optimum design. The program objectives can be achieved only through accurate process modeling and modeling of material behavior. Oftentimes, process modeling is based on some type of computational approach where as modeling of material behavior is based on

  5. Preparation and properties of Li2O-BaO-Al2O3 -SiO2 glass-ceramic materials

    Directory of Open Access Journals (Sweden)

    Gamal A. Khater

    2014-12-01

    Full Text Available The crystallization of some glasses, based on celsian-spodumene glass-ceramics, was investigated by different techniques including differential thermal analysis, optical microscope, X-ray diffraction, indentation, microhardness, bending strengths, water absorption and density measurement. The batches were melted and then cast into glasses, which were subjected to heat treatment to induce controlled crystallization. The resulting crystalline materials were mainly composed of β-eucryptite solid solution, β-spodumene solid solution, hexacelsian and monoclinic celsian, exhibiting fine grains and uniform texture. It has been found that an increasing content of celsian phase in the glasses results in increased bulk crystallization. The obtained glass-ceramic materials are characterized by high values of hardness ranging between 953 and 1013 kg/mm2, zero water absorption and bending strengths values ranging between 88 and 126 MPa, which makes them suitable for many applications under aggressive mechanical conditions.

  6. Shear Bond Strengths between Three Different Yttria-Stabilized Zirconia Dental Materials and Veneering Ceramic and Their Susceptibility to Autoclave Induced Low-Temperature Degradation.

    Science.gov (United States)

    Sehgal, Manoti; Bhargava, Akshay; Gupta, Sharad; Gupta, Prateek

    2016-01-01

    A study was undertaken to evaluate the effect of artificial aging through steam and thermal treatment as influencing the shear bond strength between three different commercially available zirconia core materials, namely, Upcera, Ziecon, and Cercon, layered with VITA VM9 veneering ceramic using Universal Testing Machine. The mode of failure between zirconia and ceramic was further analyzed as adhesive, cohesive, or mixed using stereomicroscope. X-ray diffraction and SEM (scanning electron microscope) analysis were done to estimate the phase transformation (m-phase fraction) and surface grain size of zirconia particles, respectively. The purpose of this study was to simulate the clinical environment by artificial aging through steam and thermal treatment so as the clinical function and nature of the bond between zirconia and veneering material as in a clinical trial of 15 years could be evaluated. PMID:27293439

  7. Effects of using kaolin waste and granite waste as raw materials for the production of low-water absorption ceramic tiles

    International Nuclear Information System (INIS)

    This study aims to evaluate the potential of co-use of granite waste (Rain Forest) and kaolin waste as raw material for the manufacture of ceramic coating of low water absorption. Raw materials were characterized by X-ray diffraction. Kaolin residue was added to the residue of granite in the following proportions (in wt%): 0, 10, 20, 30, 40 and 50%. Specimens were fabricated by uniaxial pressing and fired at 1175,1200 and 1225 deg C. Studies of firing linear shrinkage, water absorption, apparent porosity, apparent density and tensile bending test (or rupture modulus) were conducted. The temperature of 1225 deg C allowed the use of a mixture of 50% granite residue and 50% kaolin residue. Ceramic parts made from that mixture exhibited the maximum values required by the Brazilian Standard NBR 13818 for water absorption, shrinkage and density. (author)

  8. Analysis of crack initiation in the vicinity of an interface in brittle materials. Applications to ceramic matrix composites and nuclear fuels

    International Nuclear Information System (INIS)

    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)

  9. Shear Bond Strengths between Three Different Yttria-Stabilized Zirconia Dental Materials and Veneering Ceramic and Their Susceptibility to Autoclave Induced Low-Temperature Degradation

    Science.gov (United States)

    Sehgal, Manoti; Bhargava, Akshay; Gupta, Sharad; Gupta, Prateek

    2016-01-01

    A study was undertaken to evaluate the effect of artificial aging through steam and thermal treatment as influencing the shear bond strength between three different commercially available zirconia core materials, namely, Upcera, Ziecon, and Cercon, layered with VITA VM9 veneering ceramic using Universal Testing Machine. The mode of failure between zirconia and ceramic was further analyzed as adhesive, cohesive, or mixed using stereomicroscope. X-ray diffraction and SEM (scanning electron microscope) analysis were done to estimate the phase transformation (m-phase fraction) and surface grain size of zirconia particles, respectively. The purpose of this study was to simulate the clinical environment by artificial aging through steam and thermal treatment so as the clinical function and nature of the bond between zirconia and veneering material as in a clinical trial of 15 years could be evaluated. PMID:27293439

  10. Shear Bond Strengths between Three Different Yttria-Stabilized Zirconia Dental Materials and Veneering Ceramic and Their Susceptibility to Autoclave Induced Low-Temperature Degradation

    Directory of Open Access Journals (Sweden)

    Manoti Sehgal

    2016-01-01

    Full Text Available A study was undertaken to evaluate the effect of artificial aging through steam and thermal treatment as influencing the shear bond strength between three different commercially available zirconia core materials, namely, Upcera, Ziecon, and Cercon, layered with VITA VM9 veneering ceramic using Universal Testing Machine. The mode of failure between zirconia and ceramic was further analyzed as adhesive, cohesive, or mixed using stereomicroscope. X-ray diffraction and SEM (scanning electron microscope analysis were done to estimate the phase transformation (m-phase fraction and surface grain size of zirconia particles, respectively. The purpose of this study was to simulate the clinical environment by artificial aging through steam and thermal treatment so as the clinical function and nature of the bond between zirconia and veneering material as in a clinical trial of 15 years could be evaluated.

  11. Mechanical and trybological characterization of ceramic materials obtained of mine solid wastes; Caracterizacion mecanica y tribologica de materiales ceramicos obtenidos de residuos solidos mineros

    Energy Technology Data Exchange (ETDEWEB)

    Soto T, J.L

    2003-07-01

    A discussion of the physical, mechanical and tribological characterization of the ceramics Jaar, Jaca and Vijaar is presented in this work. They have been obtained from the industrial residuals, coming from metals and sand of the mining industry in Pachuca Hidalgo, Mexico. The methodology followed for the obtention and characterization of these ceramics consists on eliminating the cyanides from the tailings through columns coupled with a system controlled with thermostats. Then, the chemical composition is analysed with spectrometry emission of plasma and scanning electronic microscopy. Then the ceramics are produced. The base material is agglutinated with clay or kaolin. For this purpose, it was used a sintering processes and isothermal compacting in hot condition. Finally, the physical, chemical, mechanical and tribological properties of these new products are determined. Carbon, oxygen, sodium, magnesium, aluminium, manganese, silicon, potassium, phosphor, calcium, titanium, iron, molybdenum, silver and gold are in the chemical composition or ceramic analysed. Also these are heterogeneous mixture of clay and kaolin. The cyanide was eliminated. The results show that Vijaar has better wear resistances to the waste; this was demonstrated in tribology tests. They were not perforated with the abrasive particles. Also, they have high hardness and they can to support more loads in compression than Jaar and the Jaca. Consequently, they are less fragile and, therefore, they can tolerate bending stresses and bigger impact loading. (Author)

  12. Investigation of the optimal processing parameters for picosecond laser-induced microfabrication of a polymer–ceramic hybrid material

    International Nuclear Information System (INIS)

    This paper reports the effect of different process parameters on the resolution of direct laser writing by two-photon polymerization (2PP) with a low-cost Nd:YAG picosecond laser. Microstructures were fabricated from the hybrid polymer–ceramic material Ormocomp® and the impact of varying the laser beam focus position, average laser power and scanning speed were investigated in detail with scanning electron microscopy and atomic force microscopy imaging. With the appropriate laser beam focus settings, suspended structures could be fabricated. The laser intensity range of the so-called polymerization window and damage zone are reported along with the scanning speed range for producing uniform polymer lines. It is shown that very high resolution is achievable with this affordable picosecond laser 2PP system with feature sizes comparable to those previously reported for costly femtosecond laser systems. The discovered relationships between the process parameters and structure dimensions enable the design and fabrication of both 3D microstructures and nanometer scale surface features

  13. THE UTILIZATION OF Fe(III WASTE OF ETCHING INDUSTRY AS QUALITY ENHANCHEMENT MATERIAL IN CERAMIC ROOFTILE SYNTHESIS

    Directory of Open Access Journals (Sweden)

    Eva Vaulina Yulistia Delsy

    2015-11-01

    Full Text Available Waste is produced from various industrial activities. FeCl3 used in this study as an addition to the material quality in synthesis of ceramic rooftile from Kalijaran village clay, Purbalingga. Etching industrial waste FeCl3 contacted with clay. Waste being varied waste as diluted and undiluted while clay grain size varied as 60, 80, 100, 140, and 230 mesh. Both clay and waste are contacted at 30-100 minutes. The results showed that the optimum of time and grain size variation is clay with 80 mesh grain size within 70 minutes. While physical properties of the rooftile contained Fe meet all ISO standards and are known to tile, the best quality is to use clay that has been in contact with the waste that is created 1000 times dilution. The stripping test of Fe (III by rain water and sea water showed that the average rate of Fe-striped of the tile body that is made with soaked with diluted waste are 0.068 ppm/day and 0.055 ppm/day while for tile bodies soaked with waste is not diluted are 0.0722 ppm/day and 0.0560 ppm/day.

  14. Characterization and thermal performance of nitrate mixture/SiC ceramic honeycomb composite phase change materials for thermal energy storage

    International Nuclear Information System (INIS)

    The composite phase change material (PCM) comprised of the nitrate mixture KNO3/NaNO3 (50:50 mol%) and SiC ceramic honeycomb (SCH) was prepared by vacuum infiltration. The SEM (scanning electron microscope) images indicated that the nitrate mixture was dispersed and embedded in the porous structures of the SiC wall. The DSC (differential scanning calorimeter) results showed that the melting and freezing temperatures of composite PCM shifted slightly compared with those of pure PCM, and the melting and freezing latent heats of composite PCM were 72.8 J/g and 70.3 J/g, respectively. The thermal performances of the pure PCM and the composite PCMs with different mass fractions of SCH were experimentally investigated. The results showed that the heat storage and release rates increased with the increase of the mass fraction of SCH in the composite PCM. In comparison with the pure PCM, the heat storage and release time of the composite PCM with 30 wt% SCH were reduced by 52.8% and 58.3%, respectively. - Highlights: • Nitrate mixture/SCH composite PCM was prepared by vacuum infiltration. • PCM was embedded and dispersed in the porous structure of SiC wall. • SCH induced slight shift of the melting and freezing temperature of PCM. • The heat storage and release rates of PCM were improved by SCH

  15. Metals and ceramics division materials science program. Aunnual progress report for period ending June 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J.

    1979-10-01

    Progress is reported concerning theoretical studies of metals and alloys, deformation and mechanical properties, physical properties and transport phenomena, radiation effects, and engineering materials. During this period emphasis was shifted from support of nuclear technologies to support of nonnuclear energy systems. (FS)

  16. Metals and ceramics division materials science program. Aunnual progress report for period ending June 30, 1979

    International Nuclear Information System (INIS)

    Progress is reported concerning theoretical studies of metals and alloys, deformation and mechanical properties, physical properties and transport phenomena, radiation effects, and engineering materials. During this period emphasis was shifted from support of nuclear technologies to support of nonnuclear energy systems

  17. Extended defects in insulating MgAl{sub 2}O{sub 4} ceramic materials studied by PALS methods

    Energy Technology Data Exchange (ETDEWEB)

    Klym, H; Ingram, A; Shpotyuk, O; Filipecki, J; Hadzaman, I, E-mail: klymha@yahoo.com, E-mail: shpotyuk@novas.lviv.ua

    2010-11-15

    Extended positron-trapping defects in technological modified insulating nanoporous MgAl{sub 2}O{sub 4} ceramics are characterized by positron annihilation lifetime spectroscopy. The results are achieved using three-component fitting procedure with arbitrary lifetimes applied to treatment of measured spectra. Within this approach, the first component in the lifetime spectra reflects microstructure specificity of the spinel structure, the second component responsible to extended defects near intergranual boundaries and the third component correspond to ortho-positronium 'pick-off' decaying in nanopores of ceramics. It is shown that in ceramics of different technological modifications the same type of positron traps prevails.

  18. Preparation and properties of Li2O-BaO-Al2O3 -SiO2 glass-ceramic materials

    OpenAIRE

    Gamal A. Khater; Maher H. Idris

    2014-01-01

    The crystallization of some glasses, based on celsian-spodumene glass-ceramics, was investigated by different techniques including differential thermal analysis, optical microscope, X-ray diffraction, indentation, microhardness, bending strengths, water absorption and density measurement. The batches were melted and then cast into glasses, which were subjected to heat treatment to induce controlled crystallization. The resulting crystalline materials were mainly composed of β-eucryptite solid...

  19. A comparison of the wear resistance and hardness of two different indirect composite resins with a ceramic material, opposed to human enamel

    Directory of Open Access Journals (Sweden)

    Ahmet Kursad Culhaoglu

    2013-01-01

    Full Text Available Objectives: The aim of this study was to compare the two-body wear resistance of two different indirect composites and lithium disilicate porcelain versus human enamel antagonists. Materials and Methods: Ten specimens of each material (BelleGlass NG, Kerr Corp.; SR Adoro, Ivoclar Vivadent AG; IPS e.max, Ivoclar Vivadent AG were fabricated. Indirect dental composites and all-ceramic restoration were compared by an in vitro tribological test against human teeth antagonist. Wear loss of antagonist was calculated using an image analyzer (Leica Wear behavior of restorative materials was investigated with a profilometer after each individual tribological test. A scanning microscope was used to examine the crystal morphology of the samples; the crystal phases were identified by an X-ray diffractometer. Microhardness test results were analyzed using ANOVA. Kruskal Wallis multi-comparison test was used for evaluating the corrosion data. In order to understand whether there is a relationship between mean friction co-efficients, wear rate, and hardness, the statistical non-parametric relation test was used. Results: The indirect composites showed lower wear rate and friction co-efficient than all-ceramic dental materials against enamel. As for the wear loss of the enamel antagonists, the all-ceramic restorations were more harmful to human teeth than the dental composites. Conclusion: Indirect dental composite is relatively more wear-friendly than all-ceramic restoration. Furthermore, indirect composites are favorable and less offensive. Therefore, the second generation of indirect composites is promising in long-life dental restorations.

  20. An application of luminescence dating to building archaeology: The study of ceramic building materials in early medieval churches in south-eastern England and north-western France

    OpenAIRE

    Blain, Sophie

    2010-01-01

    The research reported in this thesis concerns the re-evaluation of an archaeological assumption surrounding the origin of Ceramic Building Materials (CBM) used from the 9th to the 11th century in religious buildings of north-western France and south-eastern England. Are the bricks used in the masonry structures Roman spolia or a novo productions? Amongst the dating methods that can contribute to building archaeology, it is the technique of stimulated luminescence applied to CBM ...

  1. Development of photocatalytic ceramic materials through the deposition of TiO2 nanoparticles layers

    OpenAIRE

    Carneiro, Joaquim A. O.; Teixeira, Vasco M. P.; Azevedo, Sofia; Fernandes, Filipa; Neves, Jorge

    2012-01-01

    Urbanism and communities centralization enlarges atmospheric pollution that affects both human beings as well as their constructed buildings. Different scientific and technological studies are being conducted, both in academic and construction industry, aiming the development of new construction materials with properties that can decrease visual pollution of cities, reducing also the number of cleanings required. The present research work aims the study and the production of self-cleaning ...

  2. Strength degradation and failure limits of dense and porous ceramic membrane materials

    DEFF Research Database (Denmark)

    Pećanac, G.; Foghmoes, Søren Preben Vagn; Lipińska-Chwałek, M.;

    2013-01-01

    failure potential of these membrane parts, where in a complex device also the highest residual stresses should arise due to differences in thermal expansion. In particular, sensitivity of the materials to subcritical crack growth was assessed since the long-term reliability of the component does not only...... depend on its initial strength, but also on strength degradation effects. The results were subsequently used as a basis for a strength–probability–time lifetime prediction....

  3. Properties of modified polysiloxane based ceramic matrix for long fibre reinforced composite materials

    Czech Academy of Sciences Publication Activity Database

    Chlup, Zdeněk; Černý, Martin; Strachota, Adam; Kozák, Vladislav

    2011-01-01

    Roč. 40, 6-7 (2011), s. 380-385. ISSN 1465-8011 R&D Projects: GA ČR GA106/09/1101 Institutional research plan: CEZ:AV0Z20410507; CEZ:AV0Z30460519; CEZ:AV0Z40500505 Keywords : Polysiloxane resin * Pyrolysis * Indentation Subject RIV: JI - Composite Materials Impact factor: 0.597, year: 2011

  4. Testing of ceramic filter materials at the PCFB test facility; Keraamisten suodinmateriaalien testaus PCFB-koelaitoksessa

    Energy Technology Data Exchange (ETDEWEB)

    Kuivalainen, R.; Eriksson, T.; Lehtonen, P.; Tiensuu, J. [Foster Wheeler Energia Oy, Karhula (Finland)

    1997-10-01

    Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed in Karhula, Finland since 1986. In 1989, a 10 MW PCFB test facility was constructed. The test facility has been used for performance testing with different coal types through the years 1990-1994 for obtaining data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The main objective of the project Y53 was to evaluate advanced candle filter materials for the Hot Gas Clean-up Unit (HGCU) to be used in a commercial PCFB Demonstration Project. To achieve this goal, the selected candle materials were exposed to actual high temperature, high pressure coal combustion flue gases for a period of 1000-1500 h during the PCFB test runs. The test runs were carried out in three test segments in Foster Wheeler`s PCFB test facility at the Karhula R and D Center. An extensive inspection and sampling program was carried out after the second test segment. Selected sample candles were analyzed by the filter supplier and the preliminary results were encouraging. The material strength had decreased only within expected range. Slight elongation of the silicon carbide candles was observed, but at this phase the elongation can not be addressed to creep, unlike in the candles tested in 1993-94. The third and last test segment was completed successfully in October 1996. The filter system was inspected and several sample candles were selected for material characterization. The results will be available in February - March 1997. (orig.)

  5. Femtosecond pulse laser ablation of metallic, semiconducting, ceramic, and biological materials

    Science.gov (United States)

    Kautek, Wolfgang; Krueger, Joerg

    1994-09-01

    Production of holes and grooves of microcracks extending from an annular melting zone, or substantial disruption, respectively. Experimental results are presented which demonstrate that the development of intense ultrashort pulse laser systems (>> 1012 W cm-2, (tau) bone material, and human cornea transplants. The fs-laser generates its own absorption in transparent materials by a multiphoton absorption process, and thus forces the absorption of visible radiation. Because the time is too short (< ps) for significant transport of mass and energy, the beam interaction generally results in the formation of a thin plasma layer of approximately solid state density. Only after the end of the subpicosecond laser pulse, it expands rapidly away from the surface without any light absorption and further plasma heating. Therefore, energy transfer (heat and impulse) to the target material, and thermal and mechanical disruption are minimized. In contrast to heat- affected zones (HAZ's) generated by conventional nanosecond pulse lasers of the order of 1 - 10 micrometers , HAZ's of less than 0.02 micrometers were observed.

  6. Corrosion behavior of ceramic structural materials in an electrolytic reduction process

    International Nuclear Information System (INIS)

    The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is too corrosive for typical alloying structural materials. Therefore, the choice of the optimum material for the processing equipment that handles molten salt is critical. We investigated the corrosion behaviors of CaO-stabilized ZrO2 (CSZ) and mullite (Al6Si2O13) at 650degC for 168 h in molten (1, 3) wt% Li2O-LiCl. The as-received and tested specimens were examined by scanning electron microscopy/X-ray energy dispersive spectrometry and X-ray diffraction. CSZ showed a much better hot-corrosion resistance in the presence of Li2O-LiCl molten salt than mullite. The surface corrosion layers of mullite consisted of LiAlSiO4 in 1 wt% Li2O-LiCl, and a LiAlO2 phase appeared as the Li2O concentration increased to 3 wt%. Furthermore, Li2SiO3 was the only corrosion product observed at 3 wt% Li2O-LiCl. The surface corrosion layers of CSZ were composed mainly of tetragonal-ZrO2 with partial monoclinic-ZrO2 in 1 wt% Li2O-LiCl, and a Li2ZrO3 phase appeared at 3 wt% Li2O-LiCl. There was no corrosion product detached from the surface for those specimens. CSZ was beneficial for increasing the hot-corrosion resistance of the structural materials that handle high-temperature molten salts containing Li2O. (author)

  7. Wear resistance of PM composite materials reinforced with the Ti(C,N ceramic particles

    Directory of Open Access Journals (Sweden)

    A. Włodarczyk-Fligier

    2008-10-01

    Full Text Available Purpose: of the project was evaluation of the effect of heat treatment and of the reinforcing Ti(C,N particles in the EN AW-AlCu4Mg1(A aluminium alloy on the mechanical properties, wear resistance.Design/methodology/approach: some of the composite materials were hyperquenched for 0.5 h at the temperature of 495ºC with the subsequent cooling in water, and were quench aged next for 6 h at 200°C. Hardness tests were made on HAUSER hardness tester with the Vickers method at 10 N. Abrasion resistance wear tests were carried out with the constant number of cycles of 5000 (120 m at various loads: 4, 5, 6, 7, and 8 N. Test pieces were rinsed in the ultrasonic washer to clean them and next were weighed on the analytical balance with the accuracy of 0.0001 g to check the mass loss.Findings: Besides visible improvement of mechanical properties and wear resistance there were also observed the influence of heat treatment.Practical implications: Tested composite materials can be applied among others in automotive industry but it requires additional researches.Originality/value: It was demonstrated that the mechanical properties, as well as the wear resistance of the investigated composite materials with the EN AW-Al Cu4Mg1(A alloy matrix may be formed by the dispersion hardening with the Ti(C,N particles in various portions and by the precipitation hardening of the matrix.

  8. Improvement of thermo-mechanical properties of ceramic materials for nuclear applications

    International Nuclear Information System (INIS)

    In order to improve the thermo-mechanical properties of materials used as neutron absorbers in nuclear reactors, cermet or cercer have been produced with two original microstructures: micro- or macro-dispersed composites. The composites thermal shock resistance has been evaluated in an image furnace. The microstructures we obtained involve different reinforcement mechanisms, such as crack deflection, crack branching, crack bridging or microcrack toughening, and improvement of thermal conductivity. The results reveal a significant improvement of the thermo-mechanical properties of the boron base neutron absorbers whose fabrication process leads to a macro-dispersed microstructure. (authors). 8 refs., 8 figs., 2 tabs

  9. Correlation of crack lengths from Vickers hardness indentation and fracture toughness of ceramic materials

    International Nuclear Information System (INIS)

    For hot-pressed Si3N4 and reaction-sintered Si3N4 and Al2O3 with K1sub(c)-values between 1 and 7 MNm-3sup(/)2 the method of fracture toughness determination by Vickers hardness indentation has been tested by measuring the radial cracks at the specimen surface. The correlation of crack dimensions and fracture toughness is discussed. Various evaluation methods for K1sub(c)-determination have been tested. The application of the Vickers hardness indentation method in the area of materials development and quality control is demonstrated. (orig.)

  10. Comparative evaluation of the biological properties of bone bioimplants Tutoplast® and bioactive ceramic material "Syntekost" when implanted in the middle ear in the experiment

    Directory of Open Access Journals (Sweden)

    Kravchenko S.V.

    2014-09-01

    Full Text Available Background. Trepanation cavity formed during sanitizing operation subsequently leads to a recurrence of inflammation in the middle ear cavity. A special importance in mastoidoplastics is to eliminate the postoperative cavity. One of the current problems is to create an alternative plastic material that could be used for healing of the bone defect with the newly formed bone tissue without causing further injury to the patient. Objective. The purpose of this study was to investigate and compare the features of reparative processes of bone implant Tutoplast® and bioactive ceramic material "Sintekost" as well as to assess the reaction of the inner ear to the materials which were replanted into the tympanic bullae of guinea pigs while creating an experimental model of antromastoidotomy. Methods. Experimental studies were carried out on 72 male guinea pigs of 300-400 g. Depending on the used plastic material animals were divided into 3 groups. Studies were performed on the left ear of the animal, the right ear was used as a control. Animals were withdrawn from the experiment on the 14th, 30th, 90th, 120th, 330th day. To evaluate the results of the study common histological methods were used. Results. After implanting of bioactive ceramic material "Sintekost" into tympanic bullae of guinea pigs signs of resorption of the material were mild and these processes were not always accompanied by the formation of bone tissue. The newly formed bone trabeculae were not observed until 90 day. After implanting cancellous bone crumbs "Tutoplast" into tympanic bullae of guinea pigs the initiation of osteogenesis was observed on the one hand and the resorption of bone fragments on the other. This resulted in formation of newly formed bone tissue whose volume gradually grew, filling the cavity of the tympanic bullae in that area. Implant "Tutoplast" possessed osteoplastic properties, which contributed to the growth of bone, acting as a matrix on which bone islands

  11. Ceramic thermal spray technology and explore the dense coating material%陶瓷热喷涂技术与涂层材料探密

    Institute of Scientific and Technical Information of China (English)

    肖军

    2012-01-01

    采用热喷涂技术,在金属基体上制备陶瓷涂层,能把金属材料的特点和陶瓷材料的特点有机地结合起来,获得复合材料结构。由于这种复合材料结构具有异常优越的综合性能,使得热喷涂技术迅速从高尖领域扩展应用到能源、交通、冶金、轻纺、石化、机械等民用工业领域。首先综述了热喷涂高性能陶瓷涂层的应用前景,接着分析了陶瓷涂层及热喷涂技术的特点,然后介绍了热喷涂陶瓷涂层技术的应用领域,以及热喷涂高性能陶瓷涂层的典型应用,最后讨论了热喷涂高性能陶瓷涂层的发展潜力。%using thermal spray techniques, preparation of the metal ceramic coating on the substrate, can the characteristics of metal and ceramic materials, the characteristics of organically combined to obtain composite structures. Because of this unusual composite structures with superior over- all performance, making the thermal spray technology rapidly expanding field of applications from high point to the energy, transportation, metallurgy, textile, petrochemical, machinery and other ci- vilian industries. First, an overview of high--performance ceramic thermal spray coating application prospects, and then analyzed the ceramic coating and thermal spray technology features, and then introduced the ceramic thermal spray coating technology applications, and thermal spray coating of a typical high--performance ceramic application, and finally discuss the high--performance ceramic thermal spray coatings development potential

  12. Clay raw materials from the Triassic Red Beds (Northern JaéUy Spain for making ceramic construction materials

    Directory of Open Access Journals (Sweden)

    Vázquez, M.

    2004-03-01

    Full Text Available The suitability of Triassic Red Beds from northern Jaén in the production of structural clay products has been evaluated. These materials have high phyllosilicate contents (36-69%, although some samples are enriched in quartz (<8-54% and feldspars (<5-2I%. Dolomite (<5-20% and calcite (< 7% are present. Illite is the main phyllosilicate (96-74%, kaolinite values are rather low (<17% and chlorite is present in low content (<14%. The studied samples have high silica (39.2-74.8% and alumina (6.9-18.3% content. K4ost of the samples have low CaO and MgO concentrations (<6%. <2 pm (64-36% and 2-20 pm (68-36% are the predominant grain size fraction of the studied samples. Low plasticity for extrusion process of the Triassic Red Beds is not appropriated for making bricks and roofing tiles by themselves. However, water absorption and linear shrinkage values are often suitable for manufacturing bricks. A small number of samples are appropriated for making roofing tiles, due to the its high firing shrinkage. Mixing of these materials with different proportions of complementary raw materials would allow to make porous bodies.

    En este trabajo se ha evaluado el uso de las Capas Rojas Triásicas de la Cobertera Tabular del Macizo Ibérico del norte de la provincia de Jaén para elaborar materiales cerámicos. Estos materiales tienen altos contenidos en filosilicatos (36-69%, aunque algunas muestras son ricas en cuarzo (hasta 54% y feldespatos (hasta 21%. Los carbonatos presentes en las muestras son dolomita (<5-20% y calcita (<7%. La illita es el principal filosilicato (96-74%, mientras que la caolinita y la clorita están presentes en bajos contenidos (< 17%. Las muestras estudiadas tienen altos contenidos en sílice (39,2-74,8% y alúmina (6,9-18,3%. La mayoría de estas arcillas tienen bajas concentraciones de CaO y MgO (<6%. Las fracciones granulométricas predominantes son la< 2 pm (64-36% y la situada entre 2 y 20 pm (68-36%. La baja plasticidad

  13. Study on Thermal Expansion Coefficient of Sealing Materials for Ceramic Metal Halide Lamps

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    With Al2O3, Dy2O3, and SiO2 as starting materials, the basic glass of Al2O3-Dy2O3-SiO2 system was prepared by conventional melting technology, and their thermal expansion coefficients (TECs) at different anneal time were investigated. TECs of the basic glass, which were heat-treated under different temperature, were also investigated. The result showed that TECs of the basic glass gradually approached a fixed value as the anneal time was extended, which suggested that most of the inner stress had been eliminated. After heat treatment, the contents of Dy2O3, Dy2Si2O7, and a new crystal increased up to 1200 ℃ and decreased below 1250 ℃, which was consistent with the TEC change of crystallized samples. This suggests that the crystal has a direct effect on TECs of the crystallized samples.

  14. Spectrographic Determination of Impurities in Ceramic Materials for Nuclear fusion Reactors. II. Analysis of Magnesium Aluminate

    International Nuclear Information System (INIS)

    The determination of minor and trace elements in the magnesium aluminate, considered as possible material in thermonuclear fusion reactors, has been studied. The concentration ranges are 0.1 - 0.3 % for Ca, SI and Y, and at the ppm level for Co, Cr, Fe, Hf, K, Li, Mn, Na, Ni, Se, Ta, Ti, V and Zr. Atomic emission spectroscopy with direct current are excitation and photographic detection has been employed. For Hf, Ta and Zr the use of 40% of copper fluoride as a carrier and of Nb as internal standard provide suitable sensitivities and precessions, while for the rest of elements the best results are obtained with graphite powder in different proportions and Rb or Sn as internal standard. (Author)4 refs

  15. Contribution to the determination of the expanding properties of ceramic raw materials

    Directory of Open Access Journals (Sweden)

    Lehmann, Hans

    1972-06-01

    Full Text Available Not availableLa creciente necesidad de áridos de poco peso ha conducido a la búsqueda de materias primas adecuadas y a métodos de enjuiciamiento de su idoneidad. En este trabajo se describen métodos de investigación y procedimientos de laboratorio que permiten hacer una investigación sistemática del comportamiento a la fusión y expansión de las materias primas cerámicas. Mediciones de acuerdo con estos procedimientos han dado como resultado que, sin modificar la composición material, las medidas de preparación y la técnica de procedimientos solas influyen notoriamente sobre la capacidad de expansión.

  16. Ceramic materials for primary loop magnetic flowmeters at nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Nunn, Stephen D.; Holcomb, David E. [Oak Ridge National Laboratory, Oak Ridge (United States); Chung, Chong Eun; Moon, Byung Soo [Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of); Miller, Don W. [The Ohio State University, Ohio (United States)

    2005-11-15

    Light-water cooled nuclear power plants (NPPs) use primary coolant flow measurements in their reactor thermal power determination. As such, flow measurements are important from both safety and power production perspectives. Flowmeter uncertainty thus remains a significant concern to safe and efficient NPP operation. Magnetic flowmeters are the most commonly deployed modern flowmeter and are most applicable to situations requiring high accuracy measurement of high velocity liquid flows in large pipes-a situation that closely matches NPP primary flow. They have not previously been applied to NPPs because of the environmental sensitivity of currently available component materials. The technical focus of this project was on developing, fabricating, and then assessing the environmental survivability of the ruggedized components required to apply magnetic flowmeter technology to primary coolant loops of NPPs.

  17. Ceramic materials for primary loop magnetic flowmeters at nuclear power plants

    International Nuclear Information System (INIS)

    Light-water cooled nuclear power plants (NPPs) use primary coolant flow measurements in their reactor thermal power determination. As such, flow measurements are important from both safety and power production perspectives. Flowmeter uncertainty thus remains a significant concern to safe and efficient NPP operation. Magnetic flowmeters are the most commonly deployed modern flowmeter and are most applicable to situations requiring high accuracy measurement of high velocity liquid flows in large pipes-a situation that closely matches NPP primary flow. They have not previously been applied to NPPs because of the environmental sensitivity of currently available component materials. The technical focus of this project was on developing, fabricating, and then assessing the environmental survivability of the ruggedized components required to apply magnetic flowmeter technology to primary coolant loops of NPPs

  18. Effects of sintering processes on mechanical properties and microstructure of TiB2–TiC + 8 wt% nano-Ni composite ceramic cutting tool material

    International Nuclear Information System (INIS)

    Highlights: ► TiB2–TiC + 8 wt% nano-Ni ceramic tool material was sintered by six processes. ► The properties of material depended mainly on the holding stages and duration. ► SP1 process was involved with the multiple holding stages and longer duration. ► SP1 process led to many pores, and coarsening and brittle rupture of grains. ► Tool material sintered by SP6 process exhibited the optimum mechanical properties. - Abstract: TiB2–TiC composite powder was prepared by ball-milled with ethanol and vacuum dry, and TiB2–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 TiB2–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 TiB2 and TiC grains, formation of pores and the brittle rupture of grains, which deteriorated the mechanical properties of TiB2–TiC + 8 wt% nano-Ni ceramic. TiB2–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 m1/2 and 22.54 GPa, respectively.

  19. Rechargeable lithium batteries, using sulfur-based cathode materials and Li2S-P2S5 glass-ceramic electrolytes

    International Nuclear Information System (INIS)

    All-solid-state cells, using sulfur-based cathode materials and Li2S-P2S5 glass-ceramic electrolytes exhibited excellent cycling performance at room temperature. The cathode materials consisting of sulfur and CuS were synthesized by mechanical milling, using a mixture of sulfur and copper crystals with several different molar ratios. The cell performance was influenced by the composition of S/Cu for the cathode materials and the cell with the cathode material of S/Cu = 3 prepared by milling for 15 min retained large discharge capacities over 650 mA h g-1 for 20 cycles. Sulfur as well as CuS in the cathode materials proved to be utilized as active materials on charge-discharge processes in the all-solid-state batteries

  20. Full-mouth rehabilitation with monolithic CAD/CAM-fabricated hybrid and all-ceramic materials: A case report and 3-year follow up.

    Science.gov (United States)

    Selz, Christian F; Vuck, Alexander; Guess, Petra C

    2016-02-01

    Esthetic full-mouth rehabilitation represents a great challenge for clinicians and dental technicians. Computer-aided design/ computer-assisted manufacture (CAD/CAM) technology and novel ceramic materials in combination with adhesive cementation provide a reliable, predictable, and economic workflow. Polychromatic feldspathic CAD/CAM ceramics that are specifically designed for anterior indications result in superior esthetics, whereas novel CAD/CAM hybrid ceramics provide sufficient fracture resistance and adsorption of the occlusal load in posterior areas. Screw-retained monolithic CAD/CAM lithium disilicate crowns (ie, hybrid abutment crowns) represent a reliable and time- and cost-efficient prosthetic implant solution. This case report details a CAD/CAM approach to the full-arch rehabilitation of a 65-year-old patient with toothand implant-supported restorations and provides an overview of the applied CAD/CAM materials and the utilized chairside intraoral scanner. The esthetics, functional occlusion, and gingival and peri-implant tissues remained stable over a follow-up period of 3 years. No signs of fractures within the restorations were observed. PMID:26417616

  1. MODELING AND SIMULATION OF THE EFFECT OF THE FIRING CURVE ON THE LINEAR SHRINKAGE OF CERAMIC MATERIALS: LABORATORY SCALE AND INDUSTRIAL SCALE

    Directory of Open Access Journals (Sweden)

    M. Cargnin

    2015-06-01

    Full Text Available AbstractSingle-cycle firing is currently the most widespread method used for the production of ceramic tile. The productivity is directly related to the performance of the constituent materials of the ceramic piece during thermal cycling. Numerical tools which allow the prediction of the material behavior may be of great help in the optimization of this stage. This study addressed the mathematical modeling of the temperature profile within a ceramic tile, together with the sintering kinetics, to simulate the effect of the thermal cycle on the final size. On the laboratory scale, 80 mm x 20 mm specimens with thicknesses of 2.3 mm and 7.8 mm were prepared in order to determine the kinetic constants and validate the model. The application was carried out on an industrial scale, with 450 mm x 450 mm pieces that were 8.0 mm thick. These results show that the model was capable of predicting the experimental results satisfactorily.

  2. 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.

  3. Structural Ceramics

    Science.gov (United States)

    1986-01-01

    This publication is a compilation of abstracts and slides of papers presented at the NASA Lewis Structural Ceramics Workshop. Collectively, these papers depict the scope of NASA Lewis' structural ceramics program. The technical areas include monolithic SiC and Si3N4 development, ceramic matrix composites, tribology, design methodology, nondestructive evaluation (NDE), fracture mechanics, and corrosion.

  4. III Advanced Ceramics and Applications Conference

    CERN Document Server

    Gadow, Rainer; Mitic, Vojislav; Obradovic, Nina

    2016-01-01

    This is the Proceedings of III Advanced Ceramics and Applications conference, held in Belgrade, Serbia in 2014. It contains 25 papers on various subjects regarding preparation, characterization and application of advanced ceramic materials.

  5. Selecting Ceramics - Introduction

    OpenAIRE

    Cassidy, M.

    2002-01-01

    AIM OF PRESENTATION: To compare a number of materials for extracoronal restoration of teeth with particular reference to CAD-CAM ceramics. CASE DESCRIPTION AND TREATMENT CARRIED OUT: This paper will be illustrated using clinical examples of patients treated using different ceramic restorations to present the advantages and disadvantages and each technique. The different requirements of tooth preparation, impression taking and technical procedures of each system will be presented and compar...

  6. Interaction Studies of Ceramic Vacuum Plasma Spraying For The Melting Crucible Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Hwan [Univ., of Science and Technology, Daejeon (Korea, Republic of); Kim, Hyung Tae; Woo, Yoon Myung; Kim, Ki Hwan; Lee, Chan Bock [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Fielding, R. S. [Idaho National Laboratory, Idaho (United States)

    2013-10-15

    Candidate coating materials for re-usable metallic nuclear fuel crucibles, TaC, TiC, ZrC, ZrO{sub 2}, and Y{sub 2}O{sub 3}, were plasma-sprayed onto a niobium substrate. The microstructure of the plasma-sprayed coatings and thermal cycling behavior were characterized, and U-Zr melt interaction studies were carried out. The TaC and Y{sub 2}O{sub 3} coating layers had a uniform thickness, and high density with only a few small closed pores showing good consolidation, while the ZrC, TiC, and ZrO{sub 2} coatings were not well consolidated with a considerable amount of porosity. Thermal cycling tests showed that the adhesion of the TiC, ZrC, and ZrO{sub 2} coating layers with niobium was relatively weak compared to the TaC and Y{sub 2}O{sub 3} coatings. The TaC and Y{sub 2}O{sub 3} coatings had better cycling characteristics with no interconnected cracks. In the interaction studies, ZrC and ZrO{sub 2} coated rods showed significant degradations after exposure to U-10 wt.% Zr melt at 1600 .deg. C for 15 min., but TaC, TiC, and Y{sub 2}O{sub 3} coatings showed good compatibility with U-Zr melt.

  7. Glass-ceramic material of the Si-Ca-K system sintered from sugarcane bagasse ash

    International Nuclear Information System (INIS)

    This study analyses the crystallization of glasses obtained from two samples of sugarcane bagasse ash - SCBA (named Cinza 07 and Cinza 08) mixed with carbonates (calcium and potassium). The glasses and their crystallization were examined using differential thermal analysis (DTA), X-ray fluorescence (XRF) and X-ray diffraction (XRD). The characterizations of the ashes show that they consist mainly of crystalline materials, predominantly quartz, with iron, potassium and aluminum oxides as minor elements. For the sample Cinza07 the DTA data presents broad and overlaid crystallization peaks, indicating crystallization of more than two different phases. The DTA results of samples with different grain-size distribution show that the crystallization peak intensities increase as the sample grain-size decreases, suggesting that surface crystallization actively participate on the mechanism of crystallization. For the sample Cinza 08 the DTA data presents two well defined peaks. In this case, the more intense peak was evaluated to obtain kinetic data (Eat= 355 kJ/mol) to the major phase (Wollastonita). (author)

  8. Characterization of the Materials Synthesized by High Pressure-High Temperature Treatment of a Polymer Derived t-BC2N Ceramic

    Directory of Open Access Journals (Sweden)

    Gabriela Mera

    2011-11-01

    Full Text Available Bulk B-C-N materials were synthesized under static high thermobaric conditions (20 GPa and 2,000 °C in a multianvil apparatus from a polymer derived t-BC1.97N ceramic. The bulk samples were characterised using X-ray synchrotron radiation and analytical transmission electron microscopy in combination with electron energy loss spectroscopy. Polycrystalline B-C-N materials with a cubic type structure were formed under the applied reaction conditions, but the formation of a ternary cubic diamond-like c-BC2N compound, could not be unambiguously confirmed.

  9. Thermoluminescence of natural and ceramic materials to be used in post-accidental dosimetry; Utilizacion de la termoluminiscencia de materiales naturales y ceramicos en dosimetria post-accidental

    Energy Technology Data Exchange (ETDEWEB)

    Correcher Delgado, V.

    2003-07-01

    Several studies have demonstrated that the use of luminescence techniques as a tool for retrospective dosimetry is successfully applied with ceramic materials (bricks, tiles, basin, etc) to determine the assessment of doses arising from radiation accidents. It has always relied on quartz inclusions as the main dosimetric materials extracted from the bricks. Nevertheless, there are some other minerals, mainly aluminosilicates, whose luminescence emissions continue to grow at far higher doses than quartz present no only in nature but also ceramics. These mineral phases are, in fact, much more efficient phosphors. They are used for dosimetric purposes as they are highly sensitive, reproducible, possess low fading and good dose linearity in the ranges of interest. Moreover, these materials posses the added value of their ubiquitous nature: this makes them undoubtedly useful for radiation dose assessment in uncontrolled dosimetric areas. This work focuses on the study of the thermoluminescence (TL) and radioluminescence (RL) of several natural (feldspars, leucite and kaolinite) and TL of ceramic materials (bricks) to be used for dose reconstruction. The main contributions of this study are: TL technique has been developed for accrued dose evaluation with fired quartz extracted from bricks of contaminated areas in Russia and Ukraine. The signal intensities were enough for dose estimations from levels of dose (50 mGy) corresponding to the value of background doses for a typical 20-year-old brick and upwards. It supposes a great advance since it was considered that the lower evaluation limit of luminescence techniques was 1Gy: therefore the limit of quantification has been reduced 20 times. Overall good interlaboratory concordance of dose evaluation was obtained using TL and optically stimulation luminescence (OSL) procedures for the 153 different fractions of 32 bricks examined by several European laboratories. The other main contribution consists on the characterisation

  10. Processing and characterization of an Al2O3/WC/TiC micro- nano-composite ceramic tool material

    International Nuclear Information System (INIS)

    An Al2O3-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 m1/2 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 Al2O3/16 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 Al2O3 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.

  11. Phase analysis and dielectric properties of ceramics in PbO–MgO–ZnO–Nb2O5 system: A comparative study of materials obtained by ceramic and molten salt synthesis routes

    Indian Academy of Sciences (India)

    M Thirumal; A K Ganguli

    2000-08-01

    Compositions of the type 3PbO–MgO/ZnO–Nb2O5 were synthesized by the ceramic route at 1000°C and sintered at 1200°C. Powder X-ray diffraction studies of the 1000°C heated products show the presence of the cubic pyrochlore and the columbite (Mg/ZnNb2O6) type phase in the ratio of 3 : 1 for all possible combinations of MgO and ZnO. Further heating at 1200°C led to a decrease in the cubic pyrochlore phase and an increase in the columbite phase by around 10%. Compacted pellets sintered further showed the appearance of the perovskite phase. Similar compositions synthesized using the KCl–NaCl molten salt method at 900°C for 6 h gave a significant amount of the cubic perovskite related phase of the type Pb(Mg/Zn)1/3Nb2/3O3 for all compositions containing MgO. The amount of the perovskite phase was nearly 55% for the Mg rich compositions and decreased with increase in Zn content, the pure Zn composition yielding mainly the cubic pyrochlore phase. On sintering these phases at 1000°C the perovskite phase content decreased. The dielectric constant of the composite materials formed by the ceramic route was in the region of 14 to 20 and varied little with frequency. The composites obtained by the molten salt method, however, showed much larger dielectric constants in the region 40–150 at 500 kHz for various compositions. The dielectric loss tangent of these composites were lower by an order (0.005–0.03 at 500 kHz) compared to the ceramic route.

  12. Development of advanced ceramics at AECL

    International Nuclear Information System (INIS)

    Atomic Energy of Canada Limited (AECL) has a long history of developing ceramics for nuclear fission and fusion applications. AECL is now applying its multidisciplinary materials R and D capabilities, including unique capabilities in ceramic processing and nondestructive evaluation, to develop advanced ceramic materials for commercial and industrial applications. This report provides an overview of the facilities and programs associated with the development of advanced ceramics at AECL

  13. 高性能陶瓷材料研磨抛光机设计%Design of the Machine for High Performance Ceramic Material Grinding and Polishing

    Institute of Scientific and Technical Information of China (English)

    于雷

    2012-01-01

    抽水马桶排水阀的密封环普遍采用的是橡胶材料,随着使用时间的延长或在寒冷地带使用,将会出现硬化、老化现象,从而使密封失效,造成漏水现象.陶瓷材料具有硬度高、耐磨性好、抗高温等特点,更适于制作密封环.但其加工工艺及其复杂,成品率较低,且无法大批量生产.研制一种成熟的可批量生产的陶瓷材料研磨抛光机,可大大提高其密封可靠性,降低使用成本,推动陶瓷密封环在工业和民用流体管道上的广泛应用,并在市场中占据有利地位.%The sealing ring of flush toilet drainage valves in general is rubber material,after a long time or used in cold areas,it will harden and ageing, which leads to leaking. Ceramic material is of high hardness,good abrasion resistance and resistance to elevated temperatures,so it is more suitable to be the sealing ring material.But the processing technology is very complex,the rate of finished products is very low and it could not to be mass produced.Developing a kind of mature ceramic material grinding polishing machine, which could be mass produced,will improve reliability of sealing,reduce the cost,promote the widely use of the ceramic material sealing ring,and occupy the advantageous position in the market.

  14. 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.

  15. 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.

  16. ANL-1(A) - Development of nondestructive evaluation methods for structural ceramics

    International Nuclear Information System (INIS)

    This section includes the following papers: Development of Nondestructive Evaluation Methods for Structural Ceramics; Effects of Flaws on the Fracture Behavior of Structural Ceramics; Design, Fabrication, and Interface Characterization of Ceramic Fiber-Ceramic Matrix Composites; Development of Advanced Fiber-Reinforced Ceramics; Modeling of Fibrous Preforms for CVD Infiltration; NDT of Advanced Ceramic Composite Materials; Joining of Silicon Carbide Reinforced Ceramics; Superconducting Film Fabrication Research; Short Fiber Reinforced Structural Ceramics; Structural Reliability and Damage Tolerance of Ceramic Composites for High-Temperature Applications; Fabrication of Ceramic Fiber-Ceramic Matrix Composites by Chemical Vapor Infiltration; Characterization of Fiber-CVD Matrix interfacial Bonds; Microwave Sintering of Superconducting Ceramics; Improved Ceramic Composites Through Controlled Fiber-Matrix Interactions; Evaluation of Candidate Materials for Solid Oxide Fuel Cells; Ceramic Catalyst Materials: Hydrous Metal Oxide Ion-Exchange Supports for Coal Liquefaction; and Investigation of Properties and Performance of Ceramic Composite Components

  17. Performance of Ceramics in Severe Environments

    Science.gov (United States)

    Jacobson, Nathan S.; Fox, Dennis S.; Smialek, James L.; Deliacorte, Christopher; Lee, Kang N.

    2005-01-01

    Ceramics are generally stable to higher temperatures than most metals and alloys. Thus the development of high temperature structural ceramics has been an area of active research for many years. While the dream of a ceramic heat engine still faces many challenges, niche markets are developing for these materials at high temperatures. In these applications, ceramics are exposed not only to high temperatures but also aggressive gases and deposits. In this chapter we review the response of ceramic materials to these environments. We discuss corrosion mechanisms, the relative importance of a particular corrodent, and, where available, corrosion rates. Most of the available corrosion information is on silicon carbide (SIC) and silicon nitride (Si3N4) monolithic ceramics. These materials form a stable film of silica (SO2) in an oxidizing environment. We begin with a discussion of oxidation of these materials and proceed to the effects of other corrodents such as water vapor and salt deposits. We also discuss oxidation and corrosion of other ceramics: precurser derived ceramics, ceramic matrix composites (CMCs), ceramics which form oxide scales other than silica, and oxide ceramics. Many of the corrosion issues discussed can be mitigated with refractory oxide coatings and we discuss the current status of this active area of research. Ultimately, the concern of corrosion is loss of load bearing capability. We discuss the effects of corrosive environments on the strength of ceramics, both monolithic and composite. We conclude with a discussion of high temperature wear of ceramics, another important form of degradation at high temperatures.

  18. The technical ceramics (second part)

    International Nuclear Information System (INIS)

    This work deals with ceramics used in the nuclear and the automotive industries. Concerning the nuclear sector, ceramics are particularly used in reactors, in the treatment of radioactive wastes and for the storage of the ultimate wastes. Details are given about the different ceramics used. In the automobile sector, aluminium is principally used for its lightness and cordierite, basic material of catalyst supports is especially used in the automobile devices of cleansing. (O.M.)

  19. Precision Finishing Of Ceramics

    Science.gov (United States)

    Bifano, T. G.; Blake, P. N.; Dow, T. A.; Scattergood, R. O.

    1987-01-01

    The manufacture of advanced ceramic components requires high accuracy and repeatibility in the control of the fabrication process. Surface finish in the nanometer range and excellent figure accuracy can be achieved if material can be removed from the surface without causing brittle fracture. To define the mechanism of "ductile" material removal, a series of experiments were initiated involving two processes: single-point diamond turning and diamond-wheel grinding. The results indicate that at small depths of cut, using stiff, well controlled machine tools, ceramic materials like silicon, silicon carbide, and germanium can be machined in a ductile regime.

  20. A study of the influence of the method of shaping ceramic materials prepared with waste as one of their properties; Estudio de la influencia del metodo de moldeo de materiales ceramicos elaborados a partir de residuos en sus propiedades

    Energy Technology Data Exchange (ETDEWEB)

    Cotes, M. T.; Martinez, C.; Iglesias, F. J.; Corpas, F. A.

    2013-09-01

    The properties of ceramic materials are intimately related to a variety of factors, among them shaping procedure and sintering time. These factors condition the microstructure and properties of the materials developed. Our study has formed materials from clays commonly used in the area of Bailen (Jaen) and sludge proceeding from the wastewater treatment plant. We shaped the materials through pressing and extrusion, the techniques most widely used in the ceramics industry in this region. Our goal is to determine which technique is the most appropriate by studying properties of interest, highlighting the thermal conductivity, such as compressive strength, water absorption, water suction, absolute and apparent density, among others. (Author)