Journal of the American Ceramic Society
1551-2916
0002-7820
Mỹ
Cơ quản chủ quản: WILEY , Wiley-Blackwell
Lĩnh vực:
Ceramics and CompositesMaterials Chemistry
Phân tích ảnh hưởng
Thông tin về tạp chí
The Journal of the American Ceramic Society contains records of original research that provide insight into or describe the science of ceramic and glass materials and composites based on ceramics and glasses. These papers include reports on discovery, characterization, and analysis of new inorganic, non-metallic materials; synthesis methods; phase relationships; processing approaches; microstructure-property relationships; and functionalities. Of great interest are works that support understanding founded on fundamental principles using experimental, theoretical, or computational methods or combinations of those approaches. All the published papers must be of enduring value and relevant to the science of ceramics and glasses or composites based on those materials. Papers on fundamental ceramic and glass science are welcome including those in the following areas: Enabling materials for grand challenges[...] Materials design, selection, synthesis and processing methods[...] Characterization of compositions, structures, defects, and properties along with new methods [...] Mechanisms, Theory, Modeling, and Simulation[...] JACerS accepts submissions of full-length Articles reporting original research, in-depth Feature Articles, Reviews of the state-of-the-art with compelling analysis, and Rapid Communications which are short papers with sufficient novelty or impact to justify swift publication.
Các bài báo tiêu biểu
Preparation and Characterization of Hydroxyapatite Coatings on Ti6Al4V Alloy by a Sol‐Gel Method Hydroxyapatite coatings on Ti6Al4V substrates were prepared by a sol–gel method, and characterized by X‐ray diffraction, scanning electron microscopy, and infrared reflection spectroscopy. The coatings obtained at 500°C in air had a hydroxyapatite phase, some of which was carbonated hydroxyapatite, and had a dense and smooth morphology. When the coatings were treated in a simulated body fluid, the coatings had an increase in large hydroxyapatite grains, and a rough and porous morphology. The adhesive strength of the coatings was more than 14 MPa.
Tập 82 Số 1 - Trang 27-32 - 1999
Evaluated Material Properties for a Sintered alpha‐Alumina Results of a data evaluation exercise are presented for a particular specification of sintered alpha‐alumina (mass fraction of Al2O3, ≥0.995; relative density (rho/rhotheoretical), ≥0.98; and nominal grain size, 5 μm). A comprehensive set of material property data is established based on published physical, mechanical, and thermal properties of alumina specimens that conform to the constraints of the material specification. The criteria imposed on the properties are that the values should be derived from independent experimental studies, that the values for physically related properties should be mutually self‐consistent, and that the sets of values should be compatible with established material property relations. The properties assessed in this manner include crystallography, thermal expansion, density, sound velocity, elastic modulus, shear modulus, Poisson's ratio, bulk modulus, compressive strength, flexural strength, Weibull characteristic strength, Weibull modulus, tensile strength, hardness, fracture toughness, creep rate, creep rate stress exponent, creep activation energy, friction coefficient, wear coefficient, melting point, specific heat, thermal conductivity, and thermal diffusivity.
Tập 80 Số 8 - Trang 1919-1928 - 1997
The Filler Effect: The Influence of Filler Content and Surface Area on Cementitious Reaction Rates Finely ground mineral powders are known to accelerate cement hydration rates. This “filler effect” has been attributed to the effects of dilution (w/c increase) when the cement content is reduced or to the provision of additional surface area by fine powders. The latter contribution (i.e., surface area increase) is speculated to provide additional sites for the nucleation of the hydration products, which accelerates reactions. Through extensive experimentation and simulation this study describes the influence of surface area and mineral type (e.g., quartz or limestone) on cement reaction rates. Simulations using a boundary nucleation and growth (BNG ) model and a multiphase reaction ensemble (MRE ) indicate that the extent of the acceleration is linked to the: (1) magnitude of surface area increase and (2a) capacity of the filler's surface to offer favorable nucleation sites for hydration products. Other simulations using a kinetic cellular automaton model (HydratiCA ) suggest that accelerations are linked to: (2b) the interfacial properties of the filler that alters (increases or decreases) its tendency to serve as a nucleant, and (3) the chemical composition of the filler and the tendency for its dissociated ions to participate in exchange reactions with the calcium silicate hydrate product. The simulations are correlated with accelerations observed using isothermal calorimetry when fillers partially replace cement. The research correlates and unifies the fundamental parameters that drive the filler effect and provides a mechanistic understanding of the influence of filler agents on cementitious reaction rates.
Tập 96 Số 6 - Trang 1978-1990 - 2013
Understanding the Filler Effect on the Nucleation and Growth of C‐S‐H The “filler effect”, due to the physical presence of mineral additions in cement, is mainly known to accelerate the hydration of the clinker component. Previously, this was attributed to the surface of the filler providing nucleation sites for C‐S‐H as there is a clear dependence on the surface provided by the filler particles. Our results reveal that the increase in nucleation is quite low compared to the area provided. Based on the isothermal calorimetry experiments and SEM images, we demonstrate that the most important parameter is the interparticle distance. We propose that this is mainly the result of the shearing conditions rather than extra surface available for C‐S‐H as formerly assumed. Quantitatively slag and fly ash behave very similarly to quartz. Limestone, on the other hand, seems also to stimulate C‐S‐H nucleation giving it a higher efficiency in accelerating clinker hydration.
Tập 97 Số 12 - Trang 3764-3773 - 2014
Mo<sub>5</sub>Si<sub>3</sub>‐Boron Composites Fabricated by Induction Plasma Deposition and Their High‐Temperature Oxidation Resistance Induction plasma spraying was used to produce freestanding parts of Mo5 Si3 ‐boron (Mo5 Si3 ‐B) composite materials. Four different Mo5 Si3 ‐B compositions were prepared and oxidized isothermally at 1210°C in air at atmospheric pressure. The high‐temperature oxidation performance of these materials was dependent strongly on the boron content in the specimens. The composite that contained 2.0 wt% boron exhibited excellent resistance to oxidation, as indicated by the almost‐zero change in specimen mass after oxidation for 24 h.
Tập 82 Số 8 - Trang 1965-1968 - 1999
High‐Temperature Oxidation of Molybdenum Disilicide The oxidation of MoSi2 in air at atmospheric pressure was studied by electron diffraction, X‐ray diffraction, and thermogravimetric analyses. The oxidation process occurs in two parts: (1) formation of MoO3 and SiO2 at temperatures below the boiling point of MoO3 , and (2) formation of Mo5 Si3 and SiO2 at higher temperatures. Evidence is presented which indicates that oxygen permeation through a silica layer, which may be of a mixed crystalline‐glassy nature, controls reaction rate at high temperatures and that Mo5 Si3 is present directly beneath the protective oxide. The activation energy for oxidation of MoSi2 above 1200°C was calculated as 81.3 kcal mole−1 .
Tập 49 Số 4 - Trang 173-177 - 1966
Equilibrium Dependence of the Conductivity of Pure and Tin‐Doped Indium Oxide on Oxygen Partial Pressure and Formation of an Intrinsic Defect Cluster The dependence of the electrical conductivity of pure (99.999%) and tin‐doped indium oxide (In2 O3 ) ceramics on oxygen partial pressure
was investigated at 800° and 850°C. The doping amount of tin was 100–1000 ppm, which is within the solubility limit at the temperatures measured. The conductivity of doped ceramics was independent of
and the carrier concentration was almost the same as the estimated value from the tin content. The conductivity of the pure In2 O3 ceramic was proportional to By considering a singly charged defect cluster of interstitial indium and interstitial oxygen , the conductivity dependence is deduced to be proportional to There are large and three adjacent vacant sites, 8a and 16c, in the In2 O3 structure to enter indium and oxygen.
Tập 91 Số 1 - Trang 240-245 - 2008
Electrode “Polarization” in Alkali‐Containing Glasses A model is proposed to explain the phenomenon of electrode “polarization” in glasses containing alkali oxides. The application of a dc potential to Pt electrodes on an alkali‐containing glass causes a large electric field to develop in the immediate vicinity of the anode. This high‐field region is formed by local dissociation of the alkali oxides and displacement of the dissociated ions from the region. A major hypothesis of the model is that the nonbridging oxygen ions in this region can move and can determine the electrical characteristics of the sample. Large electric fields can also develop at a partially blocking cathode as a result of the pileup of alkali ions beneath the cathode surface. Permanent compositional changes occur near both electrodes under such conditions. The model was confirmed by dc electrical measurements, electron‐microprobe data, and oxygen‐evolution data. Important physical parameters of the model were calculated from the data.
Tập 55 Số 7 - Trang 337-341 - 1972
Ion Depletion of Glass at a Blocking Anode: I, Theory and Experimental Results for Alkali Silicate Glasses A theory is presented for the ion depletion of glass beneath a blocking anode. The theoretical model is based on the assumption that the alkali ions in an alkali silicate glass have a much greater mobility than the nonbridging oxygen ions in the alkali‐depleted region. In this case, the dc conduction properties of the glass are determined by the motion of the uncombined oxygen ions in the depleted region. Expressions are derived for the spatial variation of the uncombined oxygen ions and for the current‐voltage relations in the high‐ and low‐field limits. In the high‐field limit, the theory predicts that the current will vary exponentially with the voltage; this behavior is shown in sodium silicate glasses.
Tập 57 Số 7 - Trang 291-294 - 1974
Anodic Proton Injection in Glasses Protons were injected into glasses at high temperatures using anodes such as molten NH4 HSO4 , Pt in forming gas, and graphite in an atmosphere containing H2 O vapor. Large electric fields develop near the anode surface of the glass and create an ion‐depleted region beneath the anode. The electrical conduction characteristics are attributed mainly to the motion of protons in the high‐field region. The ir absorption data indicate that injected protons exist in at least 3 bonding configurations in a proton‐exchanged region beneath the depleted region. The proton concentration in the exchanged region is estimated to be ∼80 to 95% of the Na concentration in the normal glass.
Tập 57 Số 11 - Trang 461-466 - 1974