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This study sought to create a scaffold semidegradable of magnesium and titanium with different volume percentages by powder metallurgy technique and it was undertaken to investigate the mechanical and in vitro bioactivity properties. The different volume percentages of magnesium were 30%, 35%, and 40%. The sample with 40% magnesium volume fraction, after two weeks soaking in simulated body fluid indicates 8% mass loss, eventually the sample weight decrease 16% after 24 days’ immersion in simulated body fluid. Finally, the samples were analyzed using X-ray diffraction, electron disperse spectroscopy, and optical and scanning electron microscopy. [ABSTRACT FROM PUBLISHER]

Ce-doped FeVO nanocomposites were successfully synthesized using reverse micro-emulsion route. Thermal and microstructural characteristics were comprehensively investigated by simultaneous thermal analysis, X-ray diffraction (XRD), scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and laser particle size analyzer. Moreover, as the anode material of lithium-ion batteries, the electrochemical properties were studied by galvanostatic charge and discharge tests and electrochemical impedance spectroscopy. The thermal analysis illustrated that the triclinic crystal structure of FeVO nanoparticles is formed at about 520 °C, which is confirmed by XRD and FT-IR results. Furthermore, the microstructural analyses revealed more regular particles and high specific surface area for wet-chemical derived FeVO:Ce, which decreases the diffusion pathway of the lithium ions during the insertion/extraction process. The electrochemical measurements indicated that the electrode cycling performance and rate retention ability of Ce-doped FeVO are better than those of pure FeVO due to the expansion of the crystal lattice, which provided more lattice space for lithium intercalation and de-intercalation. Consequently, the as-prepared Ce-doped FeVO with relatively high specific and reversible capacity, thermal stability and satisfactory cycling performance is a promising candidate for use as a lithium batteries anode material. [ABSTRACT FROM AUTHOR]

The sol-gel preparative method was employed to synthesize SrZnSiO:Eu nanostructure phosphors for white-light emitting diodes. The effects of calcination temperature and atmosphere as two important process parameters on the structural, morphological and optical properties were investigated using comprehensive characterization methods such as X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM) and photoluminescence spectra. The obtained phosphors are efficiently excited from 340 to 400 nm, which matches the near UV emitting InGaN chip and emits strong band peaking at 481 nm due to 4f 5d( D) → 4f( S) transition of Eu ions. In this europium-doped host lattice, a partial reduction of Eu to Eu at high temperature during the synthesis in air according to the charge compensation model is perceived. Furthermore, for this sample forbidden f-f transitions of Eu are observed. Finally, using Scherrer's equation the crystallite size of the optimum products with color coordination of x = 0.176, y = 0.193 is estimated at ~30 nm, which was consistent with TEM observations. [ABSTRACT FROM AUTHOR]

Several fluorine-substituted hydroxyapatite ceramics with the general chemical formula Ca5(PO4)3(OH)1-xFx (0≤x≤1), where x=0.0 (hydroxyapatite; HA), x=0.41 (fluorhydroxyapatite; FHA1) and x=0.69 (fluorhydroxyapatite; FHA2) and x=0.98 (fluorapatite; FA), were synthesised via pH-cycling method. The powders were characterised by using scanning electron microscope, transmission electron microscopy (TEM), Fourier transform infra-red (FTIR), X-ray diffraction (XRD) and F-selective electrode. The TEM micrographs showed that the increasing of fluoride ion concentration will cause a reduction in the aspect ratio of the produced crystallites. The XRD analysis of the calcined powders showed that all of the synthesised powders were pure and their XRD patterns were similar together. Eventually, the FTIR results suggest that the fluorine has substituted instead of hydroxyl groups in the fluoridated hydroxyapatite samples. [ABSTRACT FROM AUTHOR]

In this research, we demonstrate rapid mechanochemical synthesis of nanocrystalline α-alumina (α-Al2O3) from a starting mixture of hematite (Fe2O3) and aluminum (Al). The formation of α-Al2O3 nanocrystallites occurs during the solid-state reaction and through the reduction treatment. Also in this paper, effects of milling time on the particle size and lattice strain of nanocrystalline α-Al2O3 are investigated. The results indicate that complete reduction is reached only after 2 h of milling in a planetary mill and the crystallite size of obtained α-Al2O3 is in general about 12 nm. Also, it is found that increasing the milling time can effectively decrease the nanocrystalline size and increase the lattice strain of α-Al2O3. Finally, the experimental results show appropriate homogeneity and dispersion of related nanocrystallites. [ABSTRACT FROM AUTHOR]

Bioactive glass of the type CaO–P2O5–SiO2–MgO was obtained by the sol–gel processing method. The obtained materials were characterised by the techniques, such as X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, thermal gravimetric analysis, differential scanning caloremetry and nitrogen adsorption pore size analysis. The bioactivity was examined in vitro with respect to the ability of hydroxyapatite layer to form on the surface as a result of contact with simulated body fluid. The gel derived materials were amorphous as shown by X-ray diffraction, but were able to crystallise Ca phosphates on their surfaces when exposed to simulated body fluid. The authors also examined the alkaline phosphatase activity of osteoblasts, using human fetal osteoblastic cells (hFOB 1·19) cultured on the Mg bioglass, and compared it with the polystyrene plates. The bone cells consistently expressed higher alkaline phosphatase activity in the Mg bioactive glass materials compared with the polystyrene plates. [ABSTRACT FROM AUTHOR]

In this research, the results obtained from studying the phase transition of γ-alumina (γ-Al2O3) to α-alumina (α-Al2O3) during intense mechanical activation in high-energy ball milling are presented. The powder samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetric and Differential thermal analyses (TG-DTA). With respect to the results achieved from above analyses, the transition of γ → α-alumina through δ- and θ-phases, can be initiated. Also, it was found that the pure γ-alumina phase showed a great stability during high-energy ball milling and there was no transformation to any other phase after a long milling time (30 h). On the other hand, γ-alumina containing a small amount of the α-alumina seed, showed a gradual phase transition from γ-alumina to α-alumina in milling. The phase transition mechanism during milling is nucleation and growth, which is promoted by the α-alumina seed. [ABSTRACT FROM AUTHOR]

Abstract: A novel nanostructure pigment of Eu2+ doped SrMgAl2SiO7 was prepared via the sol–gel route. The phase composition and condition of crystallites during heating were characterized by X-ray diffraction (XRD) analysis. Investigation of optical properties by spectrophotometer illustrated that under short ultraviolet excitation wavelength, the main emission peak occurred at about 415–420nm. Also, relatively pure purplish blue color was observed that can be ascribed to the 4f65d1(2D)→4f7(8S7/2) transition of Eu2+. The effect of calcination temperature on the luminescence properties of the phosphors was evaluated and, also in this case, scanning electron microscope (SEM) was employed. From colorimetry results, color coordinations of phosphor shift towards the deep blue region as calcination temperature increases. Finally, grain size of products at optimum calcination temperature was estimated to be about 20–30nm using Scherrer’s equation, which was consistent with transmission electron microscopy (TEM) observations. [Copyright &y& Elsevier]

Abstract: Bioactive glass of the type CaO–P2O5–SiO2 was obtained by the sol–gel processing method. The obtained material was characterized by X-ray powder diffraction (XRD). Composite samples of hydroxyapatite with synthesized bioglass were prepared at 1000°C and characterized by XRD, Fourier transform infrared spectroscopy (FTIR), and surface electron microscopy (SEM). The bioactivity was examined in vitro with respect to the ability of hydroxyapatite layer to form on the surface as a result of contact with simulated body fluid (SBF). XRD, FTIR and SEM studies were conducted before and after contact of the material with SBF. It could be detected that the bioglass was crystallized partly. Furthermore, silicated hydroxyapatite may have formed due to the diffusion of silicate groups to the apatite phase and these may have substituted for the phosphate groups. It can be concluded from SEM and FTIR results that apatite phase formed after 14 days in SBF. [Copyright &y& Elsevier]

Abstract: In this study, the synthesis of SiO2–CaO–P2O5–MgO bioactive glass was performed by the sol-gel method. Sol-gel-derived bioglass material was produced both in powder and in discs form by uniaxial pressing, followed by sintering at 700 °C. The obtained material was evaluated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermal gravimetric analysis (TGA) and differential scanning caloremetry (DSC) analyses. The biocompatibility evaluation of the formed glass was assessed through in vitro cell culture [alkaline phosphatase (AP) activity of osteoblasts] experiments and immersion studies in simulated body fluid (SBF) for different time intervals while monitoring the pH changes and the concentration of calcium, phosphorus and magnesium in the SBF medium. The SEM, XRD and FTIR studies were conducted before and after soaking of the material in SBF. At first, an amorphous calcium phosphate was formed; after 7 days this surface consisted of deposited crystalline apatite. The present investigation also revealed that the sol-gel derived quaternary bioglass system has the ability to support the growth of human fetal osteoblastic cells (hFOB 1.19). Finally, this material proved to be non-toxic and compatible for the proposed work in segmental defects in the goat model in vivo. [Copyright &y& Elsevier]