Showing papers on "Ceramic published in 2000"
TL;DR: In this paper, a review of the fabrication, microstructure and mechanical properties of in situ metal matrix composites reinforced with in situ ceramic phases is presented, with particular attention paid to the mechanisms responsible for the formation of the in situ reinforcements.
Abstract: During the past decade, considerable research effort has been directed towards the development of in situ metal matrix composites (MMCs), in which the reinforcements are formed in situ by exothermal reactions between elements or between elements and compounds. Using this approach, MMCs with a wide range of matrix materials (including aluminum, titanium, copper, nickel and iron), and second-phase particles (including borides, carbides, nitrides, oxides and their mixtures) have been produced. Because of the formation of ultrafine and stable ceramic reinforcements, the in situ MMCs are found to exhibit excellent mechanical properties. In this review article, current development on the fabrication, microstructure and mechanical properties of the composites reinforced with in situ ceramic phases will be addressed. Particular attention is paid to the mechanisms responsible for the formation of in situ reinforcements, and for creep failure of the aluminum-based matrix composites.
1,474 citations
TL;DR: It is shown that fully dense cubic Y2O3 with a grain size of 60 nm can be prepared by a simple two-step sintering method, at temperatures of about 1,000 °C without applied pressure, and the suppression of the final-stage grain growth is achieved by exploiting the difference in kinetics between grain- boundary diffusion and grain-boundary migration.
Abstract: Sintering is the process whereby interparticle pores in a granular material are eliminated by atomic diffusion driven by capillary forces. It is the preferred manufacturing method for industrial ceramics. The observation of Burke and Coble that certain crystalline granular solids could gain full density and translucency by solid-state sintering was an important milestone for modern technical ceramics. But these final-stage sintering processes are always accompanied by rapid grain growth, because the capillary driving forces for sintering (involving surfaces) and grain growth (involving grain boundaries) are comparable in magnitude, both being proportional to the reciprocal grain size. This has greatly hampered efforts to produce dense materials with nanometre-scale structure (grain size less than 100 nm), leading many researchers to resort to the 'brute force' approach of high-pressure consolidation at elevated temperatures. Here we show that fully dense cubic Y2O3 (melting point, 2,439 degrees C) with a grain size of 60 nm can be prepared by a simple two-step sintering method, at temperatures of about 1,000 degrees C without applied pressure. The suppression of the final-stage grain growth is achieved by exploiting the difference in kinetics between grain-boundary diffusion and grain-boundary migration. Such a process should facilitate the cost-effective preparation of other nanocrystalline materials for practical applications.
1,328 citations
TL;DR: In this paper, the phase pure BiFeO3 was synthesized using the oxide mixing technique followed by leaching with dilute nitric acid, and X-ray diffraction pattern indicated that the sample is phase pure.
Abstract: The difficulties in synthesizing phase pure BiFeO3 are well known. In this letter we are reporting the optimized synthesis conditions for obtaining phase pure BiFeO3 ceramic. The oxide mixing technique followed by leaching with dilute nitric acid has been used for the synthesis. X-ray diffraction pattern indicated that the sample is phase pure. Scanning electron microscopy along with energy dispersive x-ray fluorescence analysis confirmed the chemical homogeneity of the sample. No segregation of the impurity phase in the matrix was detected. Moreover, Bi/Fe atomic ratio is observed to be ∼1. The ferroelectric transition of the sample at 836 °C has been detected by differential thermal analysis.
738 citations
Book•
19 Jun 2000
TL;DR: In this article, the authors present a detailed table of contents of the Ceramics Processing and Ceramic Products (CPMP) and discuss the main components of the process. But they do not provide a detailed description of the procedure.
Abstract: Partial table of contents: Ceramics Processing and Ceramic Products. Surface Chemistry. CERAMIC RAW MATERIALS. Special Inorganic Chemicals. MATERIALS CHARACTERIZATION. Particle Size and Shape. Density, Pore Structure, and Specific Surface Area. PROCESSING ADDITIVES. Liquids and Wetting Agents. Flocculants, Binders, and Bonds. PARTICLE PACKING, CONSISTENCY, AND BATCH CALCULATIONS. Batch Consistency and Formulation. PARTICLE MECHANICS AND RHEOLOGY. Mechanics of Unsaturated Bodies. BENEFICIATION. Comminution. Granulation. FORMING. Pressing. Injection Molding. POSTFORMING PROCESSES. Drying. Firing. Appendices. Index.
716 citations
TL;DR: In this article, a ceramic-powder polymer composite, making use of a relaxor ferroelectric polymer that has a high room-temperature dielectric constant as the matrix, is developed.
Abstract: A ceramic-powder polymer composite, making use of a relaxor ferroelectric polymer that has a high room-temperature dielectric constant as the matrix, is developed. The experimental data show that the dielectric constant of the composites with Pb(Mg1/3Nb2/3)O3–PbTiO3 powders can reach more than 250 with weak temperature dependence. In addition, the composites under a proper preparation procedure exhibit a high breakdown field strength (>120 MV/m), leading to a maximum energy storage density of more than 15 J/cm3. Experimental results also indicate that the high electron irradiation does not have much effect on the dielectric behavior of Pb(Mg1/3Nb2/3)O3–PbTiO3 powders, possibly due to the relaxor nature of the ceramic.
703 citations
TL;DR: In this article, the mean grain size and lattice distortion of ZnO gas sensors were calculated with the Cauchy-Cauchy and Debye-Scherrer methods, respectively.
Abstract: Nanometer ZnO gas sensing material with different particle size were made by chemical precipitation, emulsion and microemulsion, respectively. Crystal structure and ceramic microstructure of powders were determined by XRD and TEM. The mean grain size and lattice distortion of the materials were calculated with the Cauchy–Cauchy and Debye–Scherrer methods, respectively. Gas sensitivity of ZnO to H2, SF6, C4H10, gasoline, C2H5OH was measured. It can be shown from experimental results that grain size of ZnO gas-sensitive materials can be controlled by means of different processes or surfactants. The gas sensitivity of ZnO gas sensor depends upon its grain size.
694 citations
TL;DR: In this article, different thin-film deposition methods for oxides, especially for stabilized zirconia and compares them with regard to SOFC applications are presented. And each method is described with its special technical features and examples of components for fuel cells are given.
552 citations
TL;DR: In this paper, the percolation of the carbon nanotubes was studied and discussed in relation to the nature of the matrix, the electrical conductivity, the fracture strength and the fracture toughness.
530 citations
TL;DR: In this paper, a series of exposure tests was carried out with anode substrates used in SOFC development at the Research Centre Julich, where the changes in electrical conductivity as well as in the microstructure of the material were investigated.
457 citations
TL;DR: It is concluded that industrially prepared ceramics are more structurally reliable materials for dental applications although CAD-CAM procedures may induce surface and subsurface flaws that may adversely affect this property.
452 citations
TL;DR: In this paper, the normal spectral absorptance of a number of metal, ceramic and polymer powders susceptible to be utilised for selective laser sintering (SLS) technique was experimentally determined.
Abstract: The normal spectral absorptance of a number of metal, ceramic and polymer powders susceptible to be utilised for selective laser sintering (SLS) technique was experimentally determined. The measurements were performed with two laser wavelengths of 1.06μm and 10.6μm obtained by using two lasers – Nd‐YAG and CO2 respectively. The change in the powder absorptance with time during laser processing was also investigated. The effect of the absorptance characteristics on the sintering process is discussed.
TL;DR: In this paper, the synthesis, processing and properties of non-oxide silicon-based ceramic materials derived from silazanes and polysilazanes are discussed and a comprehensive review of the preparation of precursor compounds containing Si-N-Si units, including commercially available materials, is provided.
Abstract: This review highlights the synthesis, processing and properties of non-oxide silicon-based ceramic materials derived from silazanes and polysilazanes. A comprehensive summary of the preparation of precursor compounds containing Si–N–Si units, including commercially available materials, is followed by the discussion of various processing techniques. The fabrication of dense bulk ceramics in the Si/E/C/N systems is reported which involves cross-linking of the polymeric ceramic precursor followed by a polymer-to-ceramic transformation step. The cross-linked precursor can be milled, compacted and pyrolysed to form dense, additive-free, amorphous silicon carbonitride monoliths or polycrystalline composites which withstand oxidation in air at 1600°C. Furthermore, an overview is given on the fabrication of silazane derived powders and coatings involving chemical vapour deposition (CVD) methods utilising volatile precursors. Fibre spinning and fibre properties, as well as other processing techniques like infiltration of preforms, the preparation of porous ceramics and joining are briefly discussed. A state of the art of the mechanical properties of polymer derived amorphous Si/C/N and Si/B/C/N ceramics with respect to hardness as well as high-temperature creep and oxidation resistance is summarised. Finally, some important aspects of industrial applications will be considered. The review is in part based on our own work related to the polysilazane derived ceramics, but will also cover a comprehensive state of the art including the published literature in this field.
13 Apr 2000
TL;DR: In this article, the authors present a structural and physicochemical analysis of ultrahard materials, including carbon and carbonitrides, based on the CO 2 -Laser Heating Technique in a diamond cell.
Abstract: Introduction: Novel Ultrahard Materials (A. Zerr & R. Riedel) STRUCTURES AND PROPERTIES Structural Chemistry of Hard Materials (W. Jeitschko, et al.) Phase Transitions and Material Synthesis using the CO 2 -Laser Heating Technique in a Diamond Cell (A. Zerr, et al.) Mechanical Properties and their Relation to Microstructure (D. Sherman & D. Brandon) Nanostructured Superhard Materials (S. Veprek) Corrosion of Hard Materials (K. Nickel & Y. Gogotsi) Interrelations Between the Influences of Indentation Size, Surface State, Grain Size, Grain-Boundary Deformation, and Temperature on the Hardness of Ceramics (A. Krell) Transition Metal Carbides, Nitrides, and Carbonitrides (W. Lengauer) New Superhard Materials: Carbon and Silicon Nitrides (J. Lowther) Effective Doping in Novel sp 2 Bonded Carbon Allotropes (G. Jungnickel, et al.) SYNTHESIS AND PROCESSING Directed Metal Oxidation (V. Jayaram & D. Brandon) Self-Propagating High-Temperature Synthesis of Hard Materials (Z. Munir & U. Anselmi-Tamburini) Hydrothermal Synthesis of Diamond (K. Nickel, et al.) Chemical Vapor Deposition of Diamond Films (C.-P. Klages) Vapor Phase Deposition of Cubic Boron Nitride Films (K. Bewilogua & F. Richter) Polymer to Ceramic Transformation: Processing of Ceramic Bodies and Thin Films (G. Soraru & P. Colombo) MATERIALS AND APPLICATIONS Diamond Materials and their Applications (R. Caveney) Applications of Diamond Synthesized by Chemical Vapor Deposition (R. Sussmann) Diamond-like Carbon Films (C.-P. Klages & K. Bewilogua) Ceramics Based on Alumina: Increasing the Hardness for Tool Applications (A. Krell) Silicon Carbide Based Hard Materials (K. Schwetz) Silicon Nitride Based Hard Materials (M. Herrmann, et al.) Boride-Based Hard Materials (R. Telle, et al.) The Hardness of Tungsten Carbide-Cobalt Hardmetal (S. Luyckx) Data Collection of Properties of Hard Materials (G. Berg, et al.) Index
15 Aug 2000-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: Field assisted sintering technique (FAST) is a non-conventional powder consolidation method in which densification is enhanced by the application of an electrical discharge combined with resistance heating and pressure.
Abstract: Field assisted sintering technique (FAST) is a non-conventional powder consolidation method in which densification is enhanced by the application of an electrical discharge combined with resistance heating and pressure. Interest in FAST is motivated by its ability to consolidate a large variety of powder materials to high densities in short times. Full densification of metal and ceramic powders has been achieved within minutes, with a reduced number of processing steps, no need for sintering aids and more flexibility in powder handling. Although the electrical discharge effects have not been completely elucidated, distinct surface effects created by micro-discharges have been noticed in FAST consolidated specimens such as atomically clean grain boundaries and new resistivity peaks in superconductors. On-going experimental and theoretical studies to provide more quantitative insight into the relevant FAST mechanisms are presented.
TL;DR: In this article, a detailed impedance spectroscopy study was carried out on poly(ethylene oxide) [P(EO)]-based polymer electrolyte samples with and without ceramic fillers.
Abstract: The addition of nanometric fillers (e.g., , ) to polymer electrolytes induces consistent improvement in the transport properties. The increase in conductivity and in the cation transference number is attributed to the enhancement of the degree of the amorphous phase in the polymer matrix, as well as to some acid‐base Lewis type, ceramic‐electrolyte interactions. This model is confirmed by results obtained from a detailed impedance spectroscopy study carried out on poly(ethylene oxide) [P(EO)]‐based polymer electrolyte samples with and without ceramic fillers. © 2000 The Electrochemical Society. All rights reserved.
TL;DR: Since a special Y-TZP grade containing a small amount of alumina exhibited the highest damage tolerance and superior stability in an acidic environment, this material shows considerable promise for dental applications.
Abstract: This work was undertaken to evaluate the effects of dental grinding and sandblasting on the biaxial flexural strength and Weibull modulus of various Y-TZP ceramics containing 3 mol% yttria. In addition, the susceptibility of pristine and mechanically treated materials to low-temperature degradation under the conditions adopted for testing the chemical solubility of dental ceramics was investigated. The results revealed that surface grinding and sandblasting exhibit a counteracting effect on the strength of Y-TZP ceramics. Dental grinding lowered the mean strength and Weibull modulus, whereas sandblasting provided a powerful method for strengthening, but at the expense of somewhat lower reliability. The finest-grained material exhibited the highest strength after sintering, but it was less damage tolerant than tougher, coarse-grained materials. Upon extraction with the acetic acid solution and the ammonia solution, a significant amount of tetragonal zirconia had transformed to monoclinic, but extensive microcracking and attendant strength degradation had not yet occurred. Standard grade Y-TZP ceramics are more resistant in an alkaline than in an acidic environment, and there was a strong grain-size dependence of the diffusion-controlled transformation. Since a special Y-TZP grade containing a small amount of alumina exhibited the highest damage tolerance and superior stability in an acidic environment, this material shows considerable promise for dental applications.
TL;DR: In this article, pressure drop relationships were examined for 10, 30, 45 and 65 pores per inch (PPI) ceramic foam samples made from 92.0 and 99.5% α-Al2O3 and from ZrO2 stabilized with Mg, Ca, and La 2O3.
Abstract: Ceramic foams are prepared as positive images of corresponding plastic structures and exhibit bed porosities as high as 80–90%. This makes them attractive as catalyst supports in processes where high pressure drop in the reactor tube is a problem. In this research, pressure drop relationships were examined for 10, 30, 45 and 65 pores per inch (PPI) ceramic foam samples made from 92.0 and 99.5% α-Al2O3 and from ZrO2 stabilized with Mg, Ca, and La2O3. Pore distributions were determined with imaging analysis, using digital techniques. Pressure drop measurements confirmed that ceramic foams follow the Forscheimer relationship and may be interpreted with the Ergun model, in which the pressure drop is the sum of viscous and inertial terms. The Ergun parameters, α and β, are not constant, α decreases from 8.05 to 2.88 and β increases from 0.0338 to 0.111 as the pore density increases from 10 to 65 PPI. Empirical equations were developed for these parameters in terms of the mean pore size and the bed porosity, and these indicated a dependence on the media properties. Calculated pressure drop from these equations were within 15% of measured values. Up to 15 wt.% γ-Al2O3 washcoat was added to 30 PPI samples of α-Al2O3 foams. Nitrogen BET surface areas increased from about 2 m2 g−1 in the unwashcoated samples to almost 15 m2 g−1 at the highest loading. Both α and β increase linearly with the BET surface area, α by only about 50% but β by a factor of 8. This suggests that roughness introduced by the washcoat plays a dominant role in the turbulent resistance.
TL;DR: The properties of a porous hydroxyapatite ceramic produced by sintering of bovine bone were investigated by using a number of physicochemical methods such as scanning electron microscopy, SEM in combination with energy dispersive X-ray spectroscopy, mercury intrusion porosimetry, krypton-adsorption, contact angle measurements, wide angle X-rays diffraction.
TL;DR: In this paper, a personal view is presented of developments over the period 1964-1999 that have gradually made possible the fabrication of IT-SOFC stacks operating at 500°C.
Journal Article•
TL;DR: A durable resin bond strength to yttrium-oxide-partially-stabilized zirconia ceramic (YPSZ) was achieved only after air abrasion of YPSZ and using one of two resin composites containing a special phosphate monomer.
Abstract: Purpose The aim of this in vitro study was to evaluate the long-term bond strength of adhesive bonding systems to yttrium-oxide-partially-stabilized zirconia ceramic (YPSZ). Materials and methods Plexiglas tubes filled with resin composite were bonded to industrially manufactured zirconia ceramic disks (96% ZrO2 stabilized by 4% Y2O3). After air abrading the ceramic and ultrasonic cleansing, groups of 16 samples were bonded in an alignment apparatus using 7 different bonding methods. Subgroups of 8 bonded samples were tested for tensile strength following storage in distilled water at 37 degrees C either for 3 days or 2 years. In addition, the 2-year samples were thermocycled 37,500 times. The statistical analyses were conducted with the Kruskal-Wallis test followed by multiple pair-wise comparison of the groups using the Wilcoxon rank sum test. Results A moderate to relatively high initial bond strength was achieved by air abrasion alone, the additional use of a silane, or acrylizing the YPSZ surface in combination with a conventional bis-GMA resin composite. However, these methods failed spontaneously over storage time. The use of the bis-GMA resin composite after tribochemical silica coating of YPSZ and the use of a polyacid-modified resin composite after air abrasion of YPSZ resulted in a high initial bond strength which decreased significantly over storage time. A durable resin bond strength to YPSZ was achieved only after air abrasion of YPSZ and using one of two resin composites containing a special phosphate monomer. Conclusion A durable bond strength to YPSZ was achieved only by using resin composites containing a special adhesive monomer.
TL;DR: In this paper, the authors describe Si-O-C-N-B manufactured from preceramic silicon containing polymers gain in significance with increasing availability of advanced precursor materials such as poly(carbosilane), -(silazane),-(siloxane) or -(borosilazane).
Abstract: Engineering ceramics in the system Si-O-C-N-B manufactured from preceramic silicon containing polymers gain in significance with increasing availability of advanced precursor materials such as poly(carbosilane), -(silazane), -(siloxane) or -(borosilazane). While high temperature resistant Si-C and Si-N ceramic fibers are already used to reinforce ceramic matrix composites (CMC) in air- and spacecraft structures, novel products such as coatings, tapes, foams, and complex shaped components for medium and low temperature applications in the fields of energy, environmental, transportation, and communication technologies become more important in the future. Preceramic polymers offer the possibility of using versatile plastic shaping technologies as well as advanced laminated object manufacturing techniques. Properties can be varied in a wide range by tailoring the molecular structure and composition of the precursor polymer and by loading the polymer with intert or reactive filler powders. Partial conversion of the organic polymer into organic/inorganic hybrid materials yields novel materials which exhibit properties between polymers and ceramics.
Patent•
26 Sep 2000
TL;DR: In this article, an integral ceramic filter assembly is produced by adhering with a ceramic seal layer (15) outer surfaces of a plurality of filters (F1), each of the filters is formed from a sintered porous ceramic body made of α-silicon carbide and having a specific ratio of filter length to filter cross-section.
Abstract: An integral ceramic filter assembly (39) is produced by adhering with a ceramic seal layer (15) outer surfaces of a plurality of filters (F1). Each of the filters is formed from a sintered porous ceramic body made of α-silicon carbide and having a specific ratio of filter length to filter cross-section. The ceramic filter assembly has a ceramic smoothing layer (16) applied to the outer surface of the assembly, which as a whole has a generally circular cross-section or generally oval cross-section. Also disclosed is an exhaust gas purification apparatus including the filter assembly.
TL;DR: In this article, the effect of small amounts (0.8 Gd 0.2 O 2−x powder with an average crystallite size of 20 nm) of transition metal oxide doping below 2 mol.
TL;DR: In this paper, an empirical prediction model based on self-consistent theory is proposed to obtain precise prediction of effective dielectric constant of a polymer-ceramic composite for embedded capacitor application.
Abstract: Nanostructure polymer-ceramic composite with high dielectric constant (/spl epsiv//sub /spl tau///spl sim/90) has been developed for embedded capacitor application. This polymer-ceramic system consists of lead magnesium niobate-lead titanate (PMN-PT) ceramic particle and modified high-dielectric constant low-viscosity epoxy resin. In order to obtain precise prediction of effective dielectric constant of this composite, an empirical prediction model based on self-consistent theory is proposed. The electrical polarization mechanism and interaction between epoxy resin and ceramic filler has been studied. This model can establish the relevant constitutional parameters of polymer-ceramic composite materials such as particle shape, composition, and connectivity that determine the dielectric properties of the composite. This model is simpler, uses fewer parameters and its prediction compares better with experiment (error <10%). The precision and simplicity of the model can be exploited for predictions of the properties and design of nanostructure ferroelectric polymer-ceramic composites. The effective-medium theory (EMT) has been proved a good tool to predict effective properties of nanocomposites.
Journal Article•
TL;DR: Bond strengths for Twinlook and Pananvia 21 were quite low, and only Superbond showed a bond strength reasonably acceptable for clinical use; however, as no standard for bond strength has been established for inlay therapy, the other cements cannot be rejected as luting cements for inlays.
Abstract: Purpose This study was conducted to determine the bond strength of some resin luting cements to zirconia ceramic. The hypothesis was that adhesive bonding capacity is influenced by different surface pretreatments designed for milled ceramic inlays. Materials and methods Composite cylinders 5 mm x 5 mm were light cured on the ceramic surfaces for a shear test conducted in a test jig. Five surface treatments were studied: as received (from the milling machine), sandblasting with either 250- or 50-micron alumina sand, hydrofluoric acid treatment, and grinding with diamond burs. The tested luting cements were Panavia 21, Twinlook, and Superbond CB however, as no standard for bond strength has been established for inlay therapy, the other cements cannot be rejected as luting cements for inlays.
TL;DR: A nitrate-citrate gel was prepared from metal nitrates and citric acid by sol-gel process, in order to synthesize Ni 0.25 Cu 0.50 Fe 2 O 4 ferrite as discussed by the authors.
TL;DR: The final esthetic result of the all-ceramic IPS-Empress glass-ceramics restoration was not affected by the presence of different substrates with different colors when the thickness was more than 2.0 mm.
Abstract: Statement of problem: Dark-colored posts may negatively affect the esthetics of all-ceramic single unit crowns as the thin layers of luting cement may not be sufficiently opaque. Purpose: This in vitro study evaluated the influence of the color of 2 commercially available nonmetallic opaque posts (carbon fiber and zirconia) and an experimental esthetic post, and the shade and thickness of luting cements on the esthetics of all-ceramic restorations. Material and methods: Sample disks at several thickness values were made in glass-ceramic (IPS-Empress), an experimental ceramic, a zirconia, a carbon fiber post material, a resin composite material (Z100) as reference, and a luting cement (Variolink II). A laboratory procedure, with 3 possible combinations of stapling the disks, was used. This was performed for 4 substrates, 3 cement colors at 2 thickness values, and 3 heights of ceramic disks. For each combination, the shift in color was measured with a spectrophotometer. Readings were performed for 3 conditions: (1) ability of ceramic to mask the aspect of the abutment in relation to its thickness (1.0, 1.5, or 2.0 mm); (2) effect of a change in cement color (W, Y, or B) on the final color of the ceramic; and (3) influence of cement film thickness (0.1 or 0.2 mm) on the final color of the ceramic. Results: When ceramic thickness was 1 mm, all other variables were visually appreciable. For ceramic thickness of 1.5 mm, color differences decreased and most differences were appreciable only with laboratory instruments. For ceramic thickness of 2.0 mm, there were no detectable, clinically relevant differences. Conclusion: The final esthetic result of the all-ceramic IPS-Empress glass-ceramic restoration was not affected by the presence of different substrates with different colors when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5 mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0 mm, the use of a full ceramic crown is contraindicated because color matching of the abutment is required to ensure an acceptable esthetic result. Differences in cement thickness (0.1 or 0.2 mm) may slightly affect the final result. As this parameter can be controlled by the operator only to a certain extent, it cannot be considered as a procedure to correct color. Availability of different cement shades allows only minor esthetic corrections, which might be instrumentally detectable but are clinically not relevant. (J Prosthet Dent 2000;83:412-7.)
TL;DR: In this paper, the biaxial flexural strength and fracture toughness of tape-cast YSZ have been measured at room temperature and at a typical operating temperature of 900°C.
Book•
01 Jan 2000TL;DR: In this paper, the authors present a survey of the application of polysilicon and polycarbosilazenes in the following areas: 1.1.1 Chemical Vapor Deposition 3.2.2 Solid-State Reactions between Solid Compounds 2.3.4 Preceramic Polymers 3.4.5.
Abstract: Preface to the Second Edition. Foreword. Acknowledgements. Table of Contents. Abbreviations. 1 Introduction. 2 Solid-State Reactions. 2.1 Reactions Between Solid Compounds. 2.1.1 Ceramic Method. 2.1.2 Carbothermal Reduction. 2.1.3 Combustion Synthesis. 2.1.4 Sintering. 2.2 Solid-Gas Reactions. 2.3 Decomposition and Dehydration Reactions. 2.4 Intercalation Reactions. 2.4.1 General Aspects. 2.4.2 Preparative Methods. 2.4.3 Pillaring of Layered Compounds. 2.5. Further Reading. 3 Formation of Solids from the Gas Phase. 3.1 Chemical Vapor Transport. 3.2 Chemical Vapor Deposition. 3.2.1 General Aspects. 3.2.2 Metal CVD. 3.2.3 Diamond CVD. 3.2.4 CVD of Metal Oxides. 3.2.5 CVD of Metal Nitrides. 3.2.6 CVD of Compound Semiconductors. 3.3 Aerosol Processes. 3.4 Further Reading. 4 Formation of Solids from Solutions and Melts. 4.1 Glass. 4.1.1 The Structural Theory of Glass Formation. 4.1.2 Crystallization versus Glass Formation. 4.1.3 Glass Melting. 4.1.4 Metallic Glasses. 4.2 Precipitation. 4.3 Biomaterials. 4.3.1 Biogenic Materials and Biomineralization. 4.3.2 Synthetic Biomaterials. 4.3.3 Biomimetic Materials Chemistry. 4.4 Solvothermal Processes. 4.4.1 Hydrothermal Synthesis of Single Crystals. 4.4.2 Hydrothermal Synthesis. 4.4.3 Hydrothermal Leaching. 4.5 Sol-Gel Processes. 4.5.1 The Physics of Sols. 4.5.2 Sol-Gel Processing of Silicate Materials. 4.5.3 Sol-Gel Chemistry of Metal Oxides. 4.5.4 Inorganic-Organic Hybrid Materials. 4.6 Further Reading. 5 Preparation and Modification of Inorganic Polymers. 5.1 General Aspects. 5.1.1 Polymeric Materials. 5.1.2 Crosslinking. 5.1.3 Preceramic Polymers. 5.2 Polysiloxanes (Silicones). 5.2.1 Properties and Applications of Silicones. 5.2.2 Structure of Silicones. 5.2.3 Preparation of Silicones. 5.3 Polyphosphazenes. 5.3.1 Properties and Applications of Polyphosphazenes. 5.3.2 Preparation and Modification. 5.4 Polysilanes. 5.4.1 Properties and Applications of Polysilanes. 5.4.2 Preparation and Modification of Polysilanes. 5.4.3 Crosslinking of Polysilanes. 5.5 Polycarbosilanes. 5.5.1 SiC Fibers from Polycarbosilanes (Yajima Process). 5.5.2 Chemical Issues of Polymer Preparation, Curing and Pyrolysis. 5.6 Polysilazanes and Polycarbosilazanes. 5.6.1 Preparation of Polysilazanes and Polycarbosilazanes. 5.6.2 Curing and Pyrolysis Reactions. 5.7 Other Inorganic Polymers. 5.7.1 Other Phosphorus-Containing Polymers. 5.7.2 Poly(oxothiazenes). 5.7.3 Transition Metal-Containing Polymers. 5.7.4 Preceramic Polymers for BN. 5.8 Further Reading. 6 Porous Materials. 6.1 Introduction to Porosity. 6.2 Metallic Foams and Porous Metals. 6.2.1 Casting Techniques. 6.2.2 Gas-Eutectic Transformation. 6.2.3 Powder Metallurgy. 6.2.4 Metal Deposition. 6.3 Aerogels. 6.3.1 Drying Methods. 6.3.2 Properties and Applications. 6.4 Porous Solids with an Ordered Porosity. 6.4.1 Microporous Crystalline Solids. 6.4.2 Mesoporous Solids with Ordered Porosity. 6.4.3 Macroporous Solids with Ordered Porosity. 6.5 Incorporation of Functional Groups into Porous Materials. 6.6 Further Reading. 7 Nanostructured Materials. 7.1 Nanoparticles and Nanocrystalline Materials. 7.1.1 Nanocrystalline Ceramics. 7.1.2 Semiconductor Nanoparticles. 7.1.3 Metal Nanoparticles. 7.2 Nanotubes. 7.3 Mono- and Multilayers. 7.3.1 Multilayers of Inorganic Materials. 7.3.2 Langmuir Monolayers. 7.3.3 Self-assembled Monolayers. 7.4 Further Reading. 8 Glossary. Index.
TL;DR: The results indicate that cross-linked metal-containing polymers may be useful precursors to ceramic monoliths with tailorable magnetic properties.
Abstract: A shaped, magnetic ceramic was obtained from a metal-containing polymer network, which was synthesized by thermal polymerization of a metal-containing organosilicon monomer. Pyrolysis of a cylinder, shape, or film of the metal-containing polymer precursor produced a low-density magnetic ceramic replica in high yield. The magnetic properties of the shaped ceramic could be tuned between a superparamagnetic and ferromagnetic state by controlling the pyrolysis conditions, with the particular state dependent on the size of iron nanoclusters homogeneously dispersed throughout the carbosilane-graphitic-silicon nitride matrix. These results indicate that cross-linked metal-containing polymers may be useful precursors to ceramic monoliths with tailorable magnetic properties.