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Grain boundary (GB) concentration of P in 12Cr1MoV steel after aging for 15 h under elastic stress of 30 MPa is found to be nearly equal to its initial thermal equilibrium level, which confirms that elastic stress affects thermal equilibrium segregation slightly. By the model and formulation between elastic stress and segregation Gibbs energy, the effect of elastic stress on GB segregation thermodynamics of P is calculated to be slight. The consistency between experiment and calculation gives direct evidence to the validity of the model and formulation. [ABSTRACT FROM AUTHOR]

Lithium ion conducting biodegradable gel polymer electrolytes based on a poly (ε-caprolactone):lithium tetrafluoroborate (PCL:LiBF) system doped with various concentrations of 1-Ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF) ionic liquid were prepared by solution cast technique. The gel polymer electrolyte was eco-friendly, flexible, transparent and free-standing. The conductivity and transference number measurements were carried out to investigate ionic conduction and charge transport in the gel polymer electrolytes. The frequency-dependent conductivity results revealed that the room-temperature electrical conductivity increased with increasing EMIMBF concentration. At room temperature, the gel polymer electrolyte with a composition of 85PCL:15LiBF + 40EMIMBF exhibited a high conductivity value of approximately 2.83 × 10 S cm, which was favored by the rich amorphous phase as confirmed with X-ray diffraction analysis. The lithium ion transport number and electrochemical stability of the 40 % EMIMBF gel polymer electrolyte were 0.43 and 3.7 V, respectively. These values are acceptable and quite enough for practical device applications. Consequently, the 40 wt% EMIMBF incorporated gel polymer electrolyte could be used to fabricate lithium ion batteries with a suitable selection of other components of the battery system. [ABSTRACT FROM AUTHOR]

Abstract: The barium lead titanate (Ba0.8Pb0.2TiO3, termed BPT) ferroelectric ceramics were prepared using microwave sintering and spark plasma sintering (SPS) techniques. The formation of single phase was confirmed by X-ray diffraction. The SPS-prepared BPT ceramics exhibited higher density and smaller grain sizes as compared with the microwave-sintered ones. Dielectric and ferroelectric properties were compared between the two-technique-prepared ceramics. It was found that the dielectric constant at room temperature was ∼500 higher for the SPS-prepared sample than for the microwave-sintered one, and ∼6000 higher at Curie transition temperature. The remnant and spontaneous polarization values were ∼2 times larger for the SPS-prepared sample as compared with the microwave-sintered one. On the whole, the promising SPS technique possessed distinguished characteristics of energy-saving, rapid processing and uniform temperature distribution throughout the sample. [Copyright &y& Elsevier]

Hydroxyapatite/polyetheretherketone (HA/PEEK) composite materials were prepared via an in situ synthesis process in order to achieve strong bonding between PEEK matrix and hydroxyapatite fillers, and ultimately to improve the mechanical properties of the composites. In the study, the biocompatibility of the synthesized HA/PEEK materials was investigated by acute toxicity test, hemolytic test, sensitization test, pyrogen test, intradermal test, and toxicity assay test on animal tissue and cells for the purpose of examining the possible adverse effects of the residue organic chemicals from the in situ synthesis process. In vivo bioactivity of both lab-synthesized PEEK and HA/PEEK composites with various HA content was also studied. It is found that the in situ synthesized composite materials possess good biocompability without toxicity. Although the bioactivity of the material increases with HA content, the composite material with 5.6 vol % HA exhibits satisfactory bioactivity without compromising its excellent mechanical performance, which hints to a potential use as load-bearing orthopedic material. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Abstract: Coatings, which were made from pure epoxy and SiO2 nanoparticle modified epoxy composite, respectively, were applied onto the basalt fiber rovings. The SiO2 nanoparticles were synthesized using a sol–gel method and modified using coupling agent. Fourier transform infrared spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC) analyses indicated the formation of modified SiO2 nanoparticles. The SiO2 nanoparticle–epoxy composite coating gave rise to a significant increase in the tensile strength of the basalt fibers as compared with the pure epoxy coating, and also the coating endowed the basalt fiber with a promising interfacial property in the basalt fiber reinforced resin matrix composite. The coating modification was an effective way in improving the mechanical properties of basalt fibers and the properties of basalt fiber/epoxy resin composites. [Copyright &y& Elsevier]

Abstract: Several shapes of Eu2+-doped barium silicate nanostructures have been simply obtained by a hydrothermal method. Hedgehog-like, spherical-shaped, porous irregular spherical, hollow worm-like, and cracked worm shell-like structures are synthesized with changing the molar ratios of Ba/Si in solution. The possible formation mechanisms of these barium silicate nanostructures are proposed. Under an excitation wavelength of 360nm, all the products show broad emission bands from about 400 to 625nm. The UV region excitation band from 300 to 400nm confirms the possibility that the nanostructures could be used as phosphors for white LEDs. [Copyright &y& Elsevier]

Abstract: In this paper, we investigated the structure, morphology and photoluminescence properties of hexagonal SrSiO3:Eu2+ micro-octahedrons and prism-like hollow microstructures prepared by the hydrothermal method at a relatively low temperature (180°C). Reactant concentration and reaction time showed strong effects on the phase formation and morphology of the products. The prepared samples were systematically characterized by X-ray diffraction, energy dispersive X-ray spectrometry, field emission scanning electron microscopy, excitation and emission photoluminescence (PL). The possible formation mechanisms of these SrSiO3:Eu2+ microcrystals were proposed. Finally, the PL properties of SrSiO3:Eu2+ microcrystals were also investigated. [Copyright &y& Elsevier]

Abstract: The treated basalt and glass fibers with sodium hydroxide and hydrochloric acid solutions for different times were analyzed, respectively. This paper summarized the mass loss ratio and the strength maintenance ratios of the fibers after treatment. The fibers’ surface corrosion morphologies were characterized using scanning electron microscopy and their compositions were detected using energy dispersive X-ray spectroscopy. The acid resistance was much better than the alkali resistance for the basalt fibers. Nevertheless, for the glass fibers the situation is different: the acid resistance was almost the same as the alkali resistance. Among the two types of aqueous environments evaluated, the alkali solution is the most aggressive to the fibers’ surface. The possible corrosion mechanisms are revealed. [Copyright &y& Elsevier]