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Abstract: A simple and efficient way to synthesize the SiC/SiO2 nanocables decorated with the laminated porous ceramics by pyrolysis of filter papers impregnated with silicone resins in flowing argon atmosphere has been successfully developed. The phase composition of the laminated porous ceramics was measured by X-ray diffraction. The morphology and microstructure of the samples were analyzed by scanning electron microscopy and transmission electron microscopy. The experimental results show that the nanocables composed of crystalline SiC core coated with a shell of amorphous SiO2 were observed in the interfacial channels and pores of the laminated ceramics. The diameters of SiC cores were 40–80nm and the thicknesses of SiO2 shells were 4–10nm. The increase of the pyrolysis temperature caused an increase in the amount of SiC/SiO2 nanocables. Finally, a vapor–liquid–solid (VLS) process was discussed as the growth mechanism of the nanocables. [Copyright &y& Elsevier]

Zinc sulphide Quantum Dots (QDs) are semiconductor nanoparticles that have profound applications in medical imaging, photocatalysis and biosensing. Of late, green synthesis of ZnS QDs has emerged as an useful substitute for the routine chemical synthesis. The present study reports the biosynthesis of ZnS QDs using the fungus Aspergillus sp. under ambient conditions. In the present study, the mechanism behind the antibacterial action of the biosynthesized ZnS Quantum Dots has been explored. It was found that biogenesis using fungus has resulted in the synthesis of spherical crystalline ZnS particles of mean diameter 6.3 nm. FTIR analysis indicated the presence of active organic functional groups on the surface of the QDs. The optical and structural features of the biogenic ZnS were found to be comparable with that of the chemically synthesized quantum dots. Thereafter, the antibacterial activities of the biosynthesized ZnS QDs were observed against pathogenic bacteria. The green synthesized ZnS exhibited excellent antibacterial activity and were quantified using filter paper bioassay. Experimental evidences indicated that the antibacterial strategy relied on bacterial cell membrane disruption, leakage of the cytoplasmic contents and associated ROS mediated oxidative damages leading to bacterial cell lysis. Further, the prospects of biogenic ZnS for photodegradation of dyes and sensing of heavy metals in aqueous phase were investigated. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive investigation of the magnetic properties of co-precipitated Mn x Zn 1– x Fe 2 O 4 nanoferrites, where x takes the values of 0.5, 0.6, and 0.7. X-ray diffraction patterns indicated the presence of spinel phase. However, the ferrite composition x = 0.6 contains little trace of secondary phase α-Fe 2 O 3. The occurrence of cation redistribution in the current ferrite samples can be concluded from the deviation of oxygen position parameter (U) to that of optimum value (0.375). The bond angles facilitate the reduction of the A – B interaction and the increase of the B – B interaction. With the substitution of Mn2+ ions, the saturation magnetization (M s) exhibits both drops and increases whereas the coercivity (H c) consistently declines. The ferrite composition x = 0.7 exhibits the maximum value of M s and is equal to 27.9 emu/g. The blocking temperature (T B) rises in proportion to the degree of Mn2+ ion doping. The observation of quadruple doublets in the Mӧssbauer spectra indicates that the ferrite nanoparticles exist in single domain state exhibiting the quadruple interactions. The range of isomer shift (δ) 0.199–0.267 mm/s indicates the existence of exclusively high spin Fe3+ ions. Two paramagnetic doublets are anticipated to exist as a result of the core and shell of present ferrite nanoparticles. In the core-shell morphology of nanoparticles, the core is characterized by larger quadruple splitting (Δ) while the shell is characterized by smaller Δ. The results are integrated in terms of magnetocrystalline anisotropy and secondary phase presuming the core-shell structure of nanoparticles. [ABSTRACT FROM AUTHOR]

In this paper, Gd3+ doped V 2 O 5 /Ti 3 C 2 T x MXene (GVO/MX) hierarchical architectures have been synthesized by wet chemical approach. As prepared GVO/MX composite, along undoped VO and unsupported GVO were well characterized by XRD, FESEM, EDX, FT-IR and BET techniques. Electrochemical performance of VO, GVO and GVO/MX was evaluated by CV, GCD and EIS measurements. Among the three electrodes, GVO/MX composite exhibited highest electrochemical activity with the optimum specific capacitance of 1024 Fg-1 at 10 mVs−1. The specific capacitance of GVO/MX was ∼1.7 and ∼3 times higher than unsupported GVO (585 Fg-1) and VO (326 Fg-1), respectively. The cyclic life of GVO/MX with capacitance retention 96.12% was observed at 60 mVs−1. EIS measurements showed reduction in electrochemical impedance for GVO/MX as compared to GVO and VO. The corresponding impedance values of Rct and Resr for GVO/MX were calculated as 18 Ω and 1.8 Ω, respectively. The superior capacitive ability of GVO/MX can be ascribed to its unique morphology, short diffusion path and high surface area of fabricated composite. Considering it, the present work provides a feasible strategy to fabricate highly effective electrode materials for next generation energy storage devices. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates the reaction mechanism in mechanochemical synthesis of Cu 2-x Se by vibrational milling of (Cu+Se) powder mixture. The effects of milling time, milling mode, ball-to-powder weight ratio (BPWR), and Cu/Se molar ratio in the starting composition on the phase assemblage of the products are investigated. It is found that, the synthesis of Cu 2-x Se is improved by increasing milling time, BPWR, and Cu/Se ratio. For a fixed total milling time, continuous milling is better than intermittent milling to facilitate the formation of Cu 2-x Se. By continuous milling for 20 min with BPWR = 6 and Cu/Se = 2, almost single-phase β-Cu 2-x Se is produced except for minor un-reacted Cu. A diffusion-controlled reaction mechanism is proposed for the mechanochemical synthesis of Cu 2-x Se, where intermediate phases such as CuSe and Cu 3 Se 2 with lower Cu/Se ratios are produced at first and then gradually converted into Cu 2-x Se with the diffusion of Cu atoms. [ABSTRACT FROM AUTHOR]

Abstract The investigation reports in Fe 2 W 3 O 12 are few due to the synthesis difficulty of pure phase Fe 2 W 3 O 12. In the paper, rapid synthesis of pure phase Fe 2 W 3 O 12 is developed using solid state sintering method with Fe 2 O 3 and WO 3 as raw materials and the addition of MoO 3. The intermediate phase Fe 2 WO 6 is easy to form by sintering Fe 2 O 3 and WO 3 with the content of addition MoO 3 less than 3 mol%. Only after the content of addition MoO 3 reaches 5 mol%, the Fe 2 W 3 O 12 could form easily, even the temperature lower to 1000 °C. It is considered that addition MoO 3 plays as a catalyst-stabilizer in the formation of Fe 2 W 3 O 12. The as-synthesized Fe 2 W 3 O 12 shows low thermal expansion (1.35 × 10−6 °C−1) from 445° to 600 °C. [ABSTRACT FROM AUTHOR]

This paper reports the experimental results on synthesis of zirconium nitride from zircon sand through transferred arc plasma processing via carbothermal reduction and nitridation reaction. A mixture of zircon sand and carbon was processed in a transferred arc set-up in a stream of nitrogen gas. The influence of the amount of carbon and processing parameters such as input power and processing time on zirconium nitride phase formation and product morphologies were investigated by means of XRD and SEM-EDS respectively. Thermodynamic calculations were performed using free energy minimization technique to predict the conditions under which zirconium nitride is formed when zircon is processed in nitrogen atmosphere. Conversion diagrams were constructed for the ZrSiO 4 -C-N 2 system with different mole ratios of carbon. The experimental results show that the optimum mole ratio of carbon to zircon to convert zircon to zirconium nitride by this process is 1:4. Further, the results show that the plasma input power has a greater influence on the formation of zirconium nitride rather than the processing time. Experimental observations show that the optimum processing parameters for effective formation of zirconium nitride from zircon are 10 kW of plasma input power and 5 min of processing time under nitrogen environment. [ABSTRACT FROM AUTHOR]

Mullite ceramics with hollow whisker structure have been synthesized firstly through ordinary sintering process. The effects of Bi 2 O 3 and processing, on mullitization behavior and morphology development of mullite ceramics, derived from the mechanochemically activated mixture of Al 2 O 3 and SiO 2 , were investigated in this paper. When the content of Bi 2 O 3 was less than 10 mol%, the mullite grains show a short rod-like morphology, without the formation of whisker. As the content of Bi 2 O 3 was increased to more than 10 mol%, the formation temperature of mullite was decreased from 1400 °C to 1100 °C. After sintering at 1400 °C, well-developed mullite whiskers with hollow structure were formed. The formation process and growth mechanism of hollow structural whiskers in mullite ceramic doped with high content of Bi 2 O 3 were discussed in detail. [ABSTRACT FROM AUTHOR]

In this paper, a new synthetic pathway is proposed for the system YIn 1- x Mn x O 3 , a bright blue inorganic pigment, discovered in 2009. Blue pigment samples with increasing concentration of Mn 3+ ( x  = 0.08, 0.12 and 0.16) were prepared using the complex polymerization method (CPM) and compared with those synthesized via solid state reaction. All powders, the amorphous precursor from CPM and the starting materials for solid state method, were calcined at 1000, 1100, 1200 and 1300 °C for 12 h, and the resulting blue pigments were characterized by X-ray diffraction (XRD), colorimetric system CIE L*a*b* and Near infrared (NIR) reflectance measurements. XRD patterns and Rietveld Refinement show that the lowest temperature at which single hexagonal phase (isostructural to YInO 3 ) is formed is 1000 °C for CPM method and 1300 °C for conventional solid state method, respectively. The L*a*b* values demonstrate that the coloration of powders prepared by CPM exhibit temperature dependence below 1300 °C, a color shade shift from grayish blue to intense deep blue is observed when heating the samples from 1000 to 1300 °C. Blue pigments obtained by CPM have smaller particle size due to low temperatures and excellent near-infrared reflectance comparable to those by solid state method. Thus, providing advantages for application process and energy efficiency. [ABSTRACT FROM AUTHOR]

In the current paper, the synthesis of RE 2 AlTaO 7 (RE = Gd and Yb) oxides was performed through a high-temperature sintering method using Gd 2 O 3 , Yb 2 O 3 , Al 2 O 3 and Ta 2 O 5 as raw chemicals. The phase-structure, micro-morphology and thermal-physical properties of RE 2 AlTaO 7 (RE = Gd and Yb) oxides were analyzed. The RE 2 AlTaO 7 (RE = Gd and Yb) oxides exhibit single pyrochlore-type crystal-structure. Compared to Yb 2 AlTaO 7 , the Gd 2 AlTaO 7 has greater thermal conductivity owning to relatively weaker phonon scattering. Because of higher electro-negativity of Yb, the Yb 2 AlTaO 7 has lower coefficient of thermal expansion than Gd 2 AlTaO 7 . The RE 2 AlTaO 7 (RE = Gd and Yb) oxides also exhibit no phase-transition between ambient and 1473 K. [ABSTRACT FROM AUTHOR]

In the work the SHS synthesis of MAX phases from Ti-Si-C system were carried and initiated with use of 30 W laser beam with 40 µm spot. That kind of initiation allows locally and rapidly start the SHS synthesis and avoid the contamination coming from heating wire present during conventional method. The reaction was monitored by high-accuracy radiation pyrometer and high quality optical camera. The recorded data, together with reaction bed thermal conductivity measurements allowed to correlate to obtained powders composition and reaction speed. The reaction bed morphology was investigated by scanning electron microscopy with element distribution (EDS). The second part of the paper concerns laser reactive deposition of SHS in-situ synthetized MAX phases layer on silicon carbide substrate. The paths of deposited layer were formed under argon overpressure of 2 bar using 120 W of laser power. [ABSTRACT FROM AUTHOR]

It is a challenge to synthesize ultra-pure one-dimensional Ge 3 N 4 nanomaterials because the current synthetic approaches are difficult to avoid oxygen to form GeO x . In this paper, we provide a novel approach to synthesize ultra-pure Ge 3 N 4 nanowires by directly nitriding nanocrystalline Ge powder at a relatively lower temperature of 600 °C in NH 3 atmosphere. The nanocrystalline Ge powder is prepared using a liquid nitrogen cryomilling method, and an amorphous GeN x layer is formed on the surface of Ge powder to significantly block oxidation. The obtained single-crystal α-Ge 3 N 4 nanowires are ~ 80 nm in width and several tens of micrometers in length. The photoluminescence property of α-Ge 3 N 4 nanowires has also been investigated. The result exhibits a blue-green luminescence property with the main peak at 440 nm, which is originated from the electronic transition from the conduction band to valence band. [ABSTRACT FROM AUTHOR]

In this paper, Ca 6 BaP 4 O 17 :Sm 3+ and Li + co-doped Ca 6 BaP 4 O 17 :Sm 3+ phosphors were synthesized in air and argon atmospheres using a solid-state reaction method. The phosphor morphologies and crystal structure were studied using scanning electron microscopy and X-ray diffraction, respectively. The emission and absorption characteristics were investigated using photoluminescence emission spectroscopy and diffuse reflectance spectroscopy. The surface states and composition of phosphor were investigated using X-ray photoelectron spectroscopy. The emission integrated intensities of the phosphors sintered in an argon atmosphere increased 3.5 fold than the ones sintered in air atmosphere, with Li + ions becoming embedded in the lattice of the Ca 6 BaP 4 O 17 :Sm 3+ phosphor. This occurs because there are fewer defect/oxygen vacancies and less of the secondary phase forms, leading to better Sm 3+ emission. The results suggest that sintering a mixture of the raw materials of a phosphor in an argon atmosphere is a good approach for synthesizing Ca 6 BaP 4 O 17 :Sm 3+ phosphor powders. The color purity and CIE values of an optimized phosphor sample sintered in an argon atmosphere with an Li + ion compensator were calculated to be ~ 99.6% and (0.612,0.386) in the orange–red region under 405-nm excitation, respectively. Moreover, the solid solubility of Sm 3+ ions in the Ca 6 BaP 4 O 17 host can be enhanced by using an argon atmosphere in the synthesis process. [ABSTRACT FROM AUTHOR]

This paper reports a novel synthesis of iron (Fe) powders in which high-purity and controlled primary and secondary assembled particles can be produced at low cost with safe process. Iron hydroxide powder precursors with fine-sized and acicular morphology were prepared and then reduced at an optimum temperature under reducing atmosphere by using single-step and two-step reduction. In the case of two-step reduction, the precursor powders were reduced by using a hydrogen/argon mixed gas for 1.5 h with a subsequent second reduction using higher hydrogen/argon mixed gas for 2 h. The morphology of the Fe powders strongly depends on the reduction conditions and precursor's morphology. The two-step reduced powders had pure iron powders with large elongated shape and porous sponge-like interlocking structure. The synthesized Fe powders were mixed with KClO 4 and the pyrotechnic performance was examined. It is found that metal powder prepared by using two-step reduction is very suitable for producing porous sponge-like microstructure and for pyrotechnic applications. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of different particle size La 0.7 Sr 0.3 MnO 3 (LSMO) nanoparticles using non-aqueous sol gel synthesis route by calcination at temperatures 750 °C, 850 °C and 950 °C. In the present work, the effect of particle size of LSMO nanoparticles on its structural, magnetic and transport properties has been studied in detail. The X-ray diffraction analysis confirms the formation of LSMO nanoparticles having rhombohedral ( R 3 ̅ c ) structure with average particle size of 20 nm, 22.5 nm and 25.6 nm. An increase in magnetization and decrease in coercivity with increase in particle size is attributed to the magnetically disordered surface layer. The bifurcation in ZFC-FC magnetization indicates the possibility of spin glass like behavior of the LSMO nanoparticles. The effect of particle size on the resistivity and magnetoresistance were studied by using different conduction mechanism for different temperature regions. The upturn in the ρ-T curve at lower temperatures was explained by using Kondo-like transport mechanism. The maximum LFMR achieved was 32.3% at a field of 1 T at 10 K for 20 nm LSMO nanoparticle. [ABSTRACT FROM AUTHOR]

In this paper, the urea content was manipulated to synthesize nano-size AlN powders by a wet chemical route. The thermal decomposition pathway of the precursor salts and the corresponding products were discussed thoroughly. The microstructure and the morphology for both of the as-received and resultant powders were characterized by FTIR, XRD, SEM and TEM. The photoluminescence (PL) property of AlN was also used for the investigation of the microstructure defects. The effect of the urea content on the powder purity, grain crystallization, microstructure and the morphology of the AlN was studied seriously. [ABSTRACT FROM AUTHOR]

In this paper Fe-doped alumina (Al 2 O 3 ) transparent ceramics were successfully synthesized by a co-precipitation method and sintering under vacuum. The effect of Fe doping on the microstructure and transmittance of the as-prepared Al 2 O 3 ceramics was investigated in detail. Initially, Fe-doped Al 2 O 3 precursors were synthesized by a co-precipitation method using polyethylene glycol (PEG2000) and (NH 4 ) 2 SO 4 as dispersant and NH 4 HCO 3 as precipitant. Subsequently, Fe-doped Al 2 O 3 nanopowders were prepared by heat-treating the precursors at 1200 °C for 2 h. Finally, Fe-doped Al 2 O 3 ceramics were obtained by pre-heating the Fe-doped Al 2 O 3 pellets at 600 °C for 2 h and sintering at 1750 °C for 8 h under vacuum, using the Fe-doped Al 2 O 3 powders as raw material. The results show that doping by a small amount of Fe (≤ 0.15 wt%) improves the light transmittance of Al 2 O 3 ceramics. However, excessive Fe-doping leads to an increase of pores within Al 2 O 3 grains, resulting in the reduced transmittance of the final Al 2 O 3 ceramics. The obtained 0.15 wt% Fe-doped Al 2 O 3 ceramic shows total light transmittance of > 80% in the wavelength range of 300–800 nm. [ABSTRACT FROM AUTHOR]

This paper reports the luminescent response upconversion of zirconium oxide (ZrO 2 ) nanoparticles doped with erbium (Er 3+ ) and ytterbium (Yb 3+ ) ions, synthesized by hydrothermal route. X ray diffraction (DRX) showed that the synthesized material presents the face centered cubic (FCC) structure. High resolution transmission electron microscopy (HRTEM) showed the presence of crystals size smaller than 10 nm. The photoluminescent analysis allowed to observe an intense upconversion luminescence emission of the samples doped with both ions Er 3+ and Yb 3+ , when these are excited with 910 nm laser source, showing the electronic transitions 4 F 9/2 → 4 I 5/2 ; 2 H 11/2 → 4 I 5/2 ; 4 S 3/2 → 4 I 15/2 of Er 3+ . Two decay times were observed, whose behavior can be associated to the average distance between erbium ions within the nanocrystals. [ABSTRACT FROM AUTHOR]

Optical traditional techniques, such as diffusive reflectance spectroscopy, are used to confirm absorption behavior modification after anion doping process. However, the doping process in some materials as a SrTiO 3 semiconductor was not clearly proved in different anions doping cases through traditional techniques. In this case, supporting technique as electrochemical measurements could prove a great help in elucidating the doping process modifications in the semiconductor material. In this paper, the electrochemical characterization was applied to analyze changes in energy bands produced by N-doping in SrTiO 3 @SrCO 3 composite thin film electrodes. SrTiO 3 @SrCO 3 and N-doped SrTiO 3 @SrCO 3 nanoparticles were first characterized by X-ray diffraction to confirm a perovskite crystalline structure in both materials, whereas diffusive reflectance spectroscopy was used to demonstrate that no modification in the absorption spectrum is evident after doping. The thin films were observed by FESEM/SEM, and its deposition parameters were electrochemically evaluated. The electrochemical profiles of SrTiO 3 @SrCO 3 and N doped SrTiO 3 @SrCO 3 thin film electrodes were compared in dark and under UV-C light to determine the photocurrent. These measurements presented distinct results for the undoped and the doped materials, such as modification in photocurrent under UV-C illumination. SrTiO 3 @SrCO 3 composite electrodes show important characteristics which could be classified as a potential candidate in varistor uses, especially in the low-voltage protection system. The presented results confirm that electrochemical methods are useful to analyze the synthesis efficiency to produce N-doped structures. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and characterization of YBa 2 Cu 3 O 7−x (YBCO) nanoparticles obtained through an environmentally friendly chemistry approach. Y-, Cu- acetates and Ba trifluoroacetate were used for the synthesis of the precursor gel. Moreover, sucrose and pectin reagents were added as chelating agents inducing the formation of small size oxide nanoparticles. The thermal decomposition process of the precursor powder was investigated by thermal analysis correlated with mass spectrometry. The chemical nature, structure and morphology of the particles were investigated by X-Ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy. According to XRD analysis the nanoparticles have an orthorhombic structure and the average diameter between 18–30 nm, additionally confirmed by TEM measurements. The superparamagnetic behavior at room temperature of the YBCO nanoparticles has been clearly evidenced by magnetization measurements. Furthermore, the effect of the annealing atmosphere on the magnetic properties has been studied. [ABSTRACT FROM AUTHOR]

In this paper, La-Ni substituted barium ferrite nanoparticles were prepared by a co-precipitation method. The morphology, structure, magnetic and microwave absorption properties of samples were accomplished by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and vector network analysis. From the results evaluation, it can be seen that the magnetoplumbite structure for all of the samples have been formed and the average crystallite sizes of Ba 1−x La x Fe 12−x Ni x O 19 nanoparticles within in the range of 50.9–65.5 nm. Ba 0.9 La 0.1 Fe 11.9 Ni 0.1 O 19 exhibits a remarkable reflection loss of −13.5 dB at 13.05 GHz with a matching thickness of 1.5 mm. The reflection loss results indicate that Ba 0.9 La 0.1 Fe 11.9 Ni 0.1 O 19 nanoparticles may be used as a potential for thin microwave absorbers. [ABSTRACT FROM AUTHOR]

In this paper is shown that Raman spectroscopy can be used as an alternative technique to look for the best synthesis conditions of TiO 2 -based ceramics. The advantage of the Raman spectroscopy in comparison to X-ray diffraction, for example, is the reduced time to acquire the Raman spectrum, normally few seconds, using very small samples. In the TiO 2 case, this additional advantage is due to the phonon anharmonicity, in which the frequency temperature coefficient ∂ω/∂T is positive, contrary to the majority of materials. By taking the Raman spectrum in different sample temperatures and monitoring spectral modifications in the low wavenumbers range, it is possible identify the presence of non-reacted TiO 2 , which indicates that the ideal synthesis conditions were achieved or not. The presented methodology was successfully applied to the synthesis of Ni x Pb 1−x TiO 3 ceramics. [ABSTRACT FROM AUTHOR]

Despite the relatively successful effort for the synthesis of fine boron carbide (B 4 C) powders, very little is known about the underlying interrelationships between processing, compositions and the resulting product morphology for B 4 C formation via the carbothermal reduction reaction (CTR) process. In this paper, B 4 C, including uniform submicron powders, were synthesized using CTR of finely mixed boron trioxide and carbon obtained from low-cost water-soluble precursors. To understand the aforementioned interrelationships and to better control product morphology, the effects of factors such as CTR thermal profile, CTR atmosphere and precursors on product phase purity and morphology were systematically studied. Among all the factors, it was found that CTR temperature, along with total reaction time, plays a dominant role in determining the morphology of B 4 C products. Such observation was understood by analysis of CTR reaction kinetics and comparing it with microstructural evolution: significant non-uniformity in B 4 C product morphology arises from the competition between nucleation and growth at low to intermediate CTR temperatures (e.g., ~1150–1450 °C) while highly uniform submicron or nano B 4 C products result from very fast nucleation at high CTR temperatures (e.g., ≥~1750 °C) within a few minutes or even seconds. [ABSTRACT FROM AUTHOR]

In this paper, a series of novel luminescent Sr 10− x (SiO 4 ) 3 (SO 4 ) 3 O: x Eu 2+ phosphors with apatite structure were synthesized by a high temperature solid-state reaction. The phase structure, photoluminescence (PL) properties, as well as the PL thermal stability were investigated. Sr 9.92 (SiO 4 ) 3 (SO 4 ) 3 O:0.08Eu 2+ phosphor exhibits better thermal quenching resistance, retaining the luminance of 66.55% at 150 °C compared with that at 25 °C. The quenching concentration of Eu 2+ in Sr 10 (SiO 4 ) 3 (SO 4 ) 3 O was about 0.08 (mol) with the dipole–quadrupole interaction. The Sr 10− x (SiO 4 ) 3 (SO 4 ) 3 O: x Eu 2+ phosphors exhibited a broad-band green emission at 538 nm upon excitation at 396 nm. The results indicate that Sr 10− x (SiO 4 ) 3 (SO 4 ) 3 O: x Eu 2+ phosphors have potential applications as near UV-convertible phosphors for white-light UV LEDs. [ABSTRACT FROM AUTHOR]

In this paper, CaAl 2 Si x O 2 x +4 :Eu 2+ /Eu 3+ (2%, molar ratio) phosphors with different SiO 2 concentrations ( x =0, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 1.5, and 2) were prepared by a high-temperature solid-state reaction under air condition with the absence of the reduction atmosphere. The crystalline phase, photoluminescent properties and luminescent lifetimes of the prepared samples were systematically studied. The results indicated that Eu 2+ was reduced and obtained in air through self-reduction. The doping of SiO 2 in calcium aluminates strongly affects the crystalline phase, excitation and emission spectra, CIE (Commission Intemationale de I'Eclairage 1931 chromaticity) ( x , y ) position and lifetimes of europium. It is interesting and important that different luminescent colors can be obtained and modulated by changing the content of SiO 2 . [ABSTRACT FROM AUTHOR]

Synthesis of CeO 2 –Fe 2 O 3 nanoparticles via propylene oxide (PO) aided sol–gel method for the production of solar fuels via thermochemical H 2 O/CO 2 splitting cycles is reported in this paper. For the synthesis of CeO 2 –Fe 2 O 3 , cerium nitrate hexahydrate and iron nitrate nonahydrate were first dissolved in ethanol and then PO was added to this mixture as a proton scavenger to achieve the gel formation. Synthesized CeO 2 –Fe 2 O 3 gel was aged, dried, and then calcined in air to achieve the desired phase composition. Influence of different synthesis parameters on physico-chemical properties of sol-gel derived CeO 2 –Fe 2 O 3 was explored in detail by using various analytical methods such as powder x-ray diffraction (PXRD), BET surface area analyzer (BET), x-ray energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HR–TEM). According to the findings, at all experimental conditions, phase/chemical composition of sol–gel derived CeO 2 –Fe 2 O 3 was observed to be unaltered. The SSA and pore volume was increased with the upsurge in the amount of PO used during sol–gel synthesis and decreased with the rise in the calcination temperature and dwell time. In contrast, the crystallite size was enlarged with the increase in the calcination temperature and dwell time. The nanoparticle morphology of the sol–gel derived CeO 2 –Fe 2 O 3 was verified with the help of SEM/TEM analysis. Thermochemical CO production ability of sol–gel derived CeO 2 –Fe 2 O 3 was investigated by performing thermogravimetric thermal reduction and CO 2 splitting experiments in the temperature range of 1000–1400 °C. Reported results indicate that the sol–gel derived CeO 2 –Fe 2 O 3 produced higher amounts of O 2 (69.134 μmol/g) and CO (124.013 μmol/g) as compared to previously investigated CeO 2 and CeO 2 –Fe 2 O 3 in multiple thermochemical cycles. It was also observed that the redox reactivity and thermal stability of sol–gel derived CeO 2 –Fe 2 O 3 remained unchanged as it produced constant amounts of O 2 and CO in eight successive thermochemical cycles. [ABSTRACT FROM AUTHOR]

In this paper, a series of novel luminescent Sr 1− x Al 12 O 19 : x Eu 2+ phosphors were synthesized by a high temperature solid-state reaction. The phase structure, photoluminescence (PL) properties, as well as the decay curves were investigated. The quenching concentration of Eu 2+ in SrAl 12 O 19 was about 0.15 (mol). Upon excitation at 378 nm, the composition-optimized Sr 0.85 Al 12 O 19 :0.15Eu 2+ exhibited strong broad-band green emission at 530 nm with the CIE chromaticity (0.2917, 0.5736). The results indicate that Sr 1− x Al 12 O 19 : x Eu 2+ phosphors have potential applications as green-emitting phosphors for UV-pumped white-light LEDs. [ABSTRACT FROM AUTHOR]

In this paper, the synthesis of ferroelectric (1− x )(Na 0.5 Bi 0.5 )TiO 3 (NBT)– x BaTiO 3 (BT) ceramics of different compositions ( x =0.07, 0.06 wt%) around the morphotropic phase boundary (MPB) by solid state reaction technique has been reported. From the Scanning Electron Microscopy (SEM) analysis, the pebble-like morphology of the synthesized ceramics has been changed to regular cube-like morphology for higher BT concentration. The phase coexistence and crystal structure have been determined by using X-ray powder diffraction. Presence of functional groups has been identified by Raman Spectroscopy at room-temperature. The dielectric properties of the ceramics were investigated in the frequency range of 200 Hz–2 MHz from room temperature to 500 °C. The broad dielectric peak and frequency dispersion demonstrate the relaxor behavior of ceramics. The dielectric constant ( ε r ), transition temperature ( T m ), depolarization temperature ( T d ) and diffusive factor ( γ ) are found to be comparatively good and tabulated for 5 kHz. The ac conductivity follows jump relaxation model at low frequency and double power at high frequency and temperature. For these ceramics P – E loops with high remnant polarization were obtained at room temperature. The d 33 values for NBT–BT 94/6 and NBT–BT 93/7 were 85 and 102 pC/N respectively. The open circuit g – constants have been calculated and it is high for NBT–BT 93/7. [ABSTRACT FROM AUTHOR]

This paper reports on the synthesis of pristine α-Fe 2 O 3 nanorods and Fe 2 O 3 –ZnO core–shell nanorods using a combination of thermal oxidation and atomic layer deposition (ALD) techniques; the completed nanorods were then used for ethanol sensing studies. The crystal structure and morphology of the synthesized nanostructures were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The sensing properties of the pristine and core–shell nanorods for gas-phase ethanol were examined using different concentrations of ethanol (5–200 ppm) at different temperatures (150–250 °C). The XRD and SEM revealed the excellent crystallinity of the Fe 2 O 3 –ZnO core–shell nanorods, as well as their uniformity in terms of shape and size. The Fe 2 O 3 –ZnO core–shell nanorod sensor showed a stronger response to ethanol than the pristine Fe 2 O 3 nanorod sensor. The response (i.e., the relative change in electrical resistance R a / R g ) of the core–shell nanorod sensor was 22.75 for 100 ppm ethanol at 200 °C whereas that of the pristine nanorod sensor was only 3.85 under the same conditions. Furthermore, under these conditions, the response time of the Fe 2 O 3 –ZnO core–shell nanorods was 15.96 s, which was shorter than that of the pristine nanorod sensor (22.73 s). The core–shell nanorod sensor showed excellent selectivity to ethanol over other VOC gases. The improved sensing response characteristics of the Fe 2 O 3 –ZnO core–shell nanorod sensor were attributed to modulation of the conduction channel width and the potential barrier height at the Fe 2 O 3 –ZnO interface accompanying the adsorption and desorption of ethanol gas as well as to preferential adsorption and diffusion of oxygen and ethanol molecules at the Fe 2 O 3 –ZnO interface. [ABSTRACT FROM AUTHOR]

Lanthanum titanium aluminium oxide (LaTi 2 Al 9 O 19 , LTA) synthesized by solid state reaction has been proven to be a promising thermal barrier material. However, LTA synthesized via solid state reaction requires a high processing temperature of at least 1500 °C for 24 h. In this paper, single phase LTA was synthesized by sol–gel at a lower temperature (1350 °C) and the process parameters, phase composition, and relative thermal properties were investigated. Two-step calcination was used to obtain fine LTA powders. According to X-ray diffraction, the best calcination temperature of sol–gel synthesized LTA is 1350 °C. XRD results also showed the thermochemical stability of sol–gel synthesized LTA, which does not react with Al 2 O 3 up to 1500 °C, to be excellent. Compared to LTA synthesized by solid state reaction, sol–gel synthesized LTA has higher coefficients of thermal expansion (CTEs) which are circa 10.2×10 −6 °C −1 at 950 °C, related to the size dependent characteristic of CTEs. Therefore, sol–gel synthesized LTA can be a promising candidate as a thermal barrier material on Ni-based superalloys. [ABSTRACT FROM AUTHOR]

This paper describes a novel sol–gel route for the in situ synthesis of heterostructure materials, and discusses the effects of two different pH levels on the characteristics of the raw powders and on the microstructure and electric properties of microwave-sintered PZT/CoFe 2 O 4 (80/20) composites. The results indicate that the two pH levels evaluated here allowed for the successful production of biphasic nanocrystalline PZT/CoFe 2 O 4 with two immiscible phases and without spurious phases. However, the synthesis performed in acid pH resulted in the formation of large self-assembled agglomerates without a well-defined structure, showing poor sinterability and inhomogeneous distribution of the two phases in the ceramic composite. In contrast, the powders synthesized in basic pH showed a more well-defined nanoparticle morphology with very small and uniform spherical particles. The microwave-sintered dense ceramic samples obtained in basic pH showed highly homogeneous distribution of the two constituent phases without percolation of the ferrite phase and, unlike the samples obtained by conventional sintering, they exhibited high electrical resistivity, confirming their greater phase integrity. This may be attributed to the adjustment of the synthesis parameters of nanocrystalline heterostructured materials prepared with PZT/CoFe 2 O 4 raw powder, as well as the microwave sintering process, whose synergistic effect specifically improves the microstructure. The magnetoelectric response of these composites confirms their promising potential for application in multifunctional devices. [ABSTRACT FROM AUTHOR]

In this paper, the effects of acceptor dopants on the synthesis, sintering and properties of KNN ceramics were studied for (K 0.5 Na 0.5 )(Nb 0.994 A 0.006 )O 3− δ (A=Ge 4+ , Ga 3+ , Zn 2+ , Mn 2+ , Ni 2+ , and Cu 2+ ) ceramics. The results reveal that the eutectic phase(s) is (are) formed between the acceptor oxide and alkali metal carbonate, thereby significantly improving the sinterability of the materials. Compared to the trivalent and tetravalent acceptor dopants, divalent dopant can lead to higher Q m values, most likely due to the formation of defect complexes. [ABSTRACT FROM AUTHOR]

The present paper reports the synthetic route of Bi 2 O 3 with rod-like architectures and its applications in supercapacitors. The rod-like Bi 2 O 3 was prepared via a sol–gel method using Bi(NO 3 ) 3 ·5H 2 O as a precursor. The structures and morphology of the synthesized samples were characterized by X-ray diffractions (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and nitrogen gas sorption, while their electrochemical properties were carried out using cyclic voltammetry (CV), galvanostatic charge–discharge test and electrochemical impedance spectroscopy (EIS). XRD patterns revealed that the pure β-Bi 2 O 3 phase was obtained and the electrochemical measurement showed that the material exhibited a specific capacitance of 528 F g −1 at the scan rate of 5 mV s −1 with superior rate capability. Furthermore, the electrode material shows good cycle stability in the potential range of −1.1 to 0.2 V (vs. saturated calomel electrode (SCE)) after 1000 cycles. The results indicate that the as-prepared Bi 2 O 3 is a promising electrode material for pseudocapacitors application. [ABSTRACT FROM AUTHOR]

In this paper, barium titanate nanopowders were obtained by combination of sol–gel and hydrothermal methods, starting from tetrabutyltitanate and barium acetate. Our work was focused on low-temperature synthesis route, as well as structural and morphological characterization of the resulted nanopowders. Moreover, the structure type of barium titanate and magnetic behavior were established. [ABSTRACT FROM AUTHOR]

The effect of Mn doping on the structural physical, morphological and optical properties of Zn 1− x Mn x O nanoparticles prepared by novel co-precipitation route. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis spectroscopy. Broad peaks observed in XRD patterns indicates that all samples were nanocrystalline with hexagonal phase. Studied lattice parameters and volume of unit cell as a function of Mn content. The crystalline size, lattice strain, stress and strain energy density of Mn doped ZnO nanoparticles were determined from XRD patterns using W–H three models. The results obtained yields strain, stress and strain energy density increases with increasing Mn content and crystalline size decrease. Among the developed models, UEDM model was observed to be the best fit for co-precipitation route. The transmission electron microscopy (TEM) result confirms that mean particle size of Zn 1− x Mn x O nanoparticles were about 20–27 nm. The optical study shows the decrease in optical energy band gap with Mn doping and confirm that Mn 2+ ions substituting in ZnO materials. The u parameter and bond length of Mn doped ZnO nanoparticles were also investigated in this paper. [ABSTRACT FROM AUTHOR]

Due to the extremely harsh reaction conditions, it is very difficult to control the particle morphology during the synthesis of ZrC, a well-known ultra high temperature ceramic material. In this paper, carbon encapsulated zirconia microspheres (ZrO 2 @C) are synthesized via two consecutive hydrothermal reactions in one pot. After carbothermal reduction, ZrC particles with controlled spherical morphology can be prepared. The spherical morphology suggests that carbon diffuses into zirconia during carbothermal reduction. The influences of reactant concentrations, reaction time and temperature on the microencapsulation process are also investigated. Meanwhile, as a comparison, zirconia coated carbon microspheres (C@ZrO 2 ) are also prepared, which results in ZrC particles with layered structure. [ABSTRACT FROM AUTHOR]

Artificial intelligence (AI) approach has been successfully applied to a wide range of materials engineering problems so far. However, there is no work on incorporation of modeling algorithms based on AI to predict the performance of thermoelectric materials. This paper shows how to predict the dimensionless thermoelectric figure of merit of Sr 1− x Y x TiO 3 ceramics as the performance symbol of these structures, using an adaptive neuro-fuzzy inference system (ANFIS). Moreover, this work investigates the effect of the process parameters including Y content, compact pressure, sintering temperature, sintering time and process temperature on the performance of Sr 1− x Y x TiO 3 thermoelectric ceramics. Absolute fraction of variance and root mean square error of 0.99 and 0.008, in training and testing phases of the model were achieved showing the relatively high accuracy of the proposed ANFIS model. To investigate the effect of the synthesis method (synthesis type) of Sr 1− x Y x TiO 3 ceramics on the performance of these materials, this parameter was also introduced to the model and the obtained results were shown in 3D graphs. These 3D interaction graphs between some of process variables generated by the proposed model indicated that the combustion synthesis is more effective than other ones to increase the efficiency of the Sr 1− x Y x TiO 3 thermoelectric ceramics. [ABSTRACT FROM AUTHOR]

Due to the extremely harsh reaction conditions, it is very difficult to control the particle morphology during the synthesis of ZrC, a well-known ultra high temperature ceramic material. In this paper, carbon encapsulated zirconia microspheres (ZrO 2 @C) are synthesized via two consecutive hydrothermal reactions in one pot. After carbothermal reduction, ZrC particles with controlled spherical morphology can be prepared. The spherical morphology suggests that carbon diffuses into zirconia during carbothermal reduction. The influences of reactant concentrations, reaction time and temperature on the microencapsulation process are also investigated. Meanwhile, as a comparison, zirconia coated carbon microspheres (C@ZrO 2 ) are also prepared, which results in ZrC particles with layered structure. [ABSTRACT FROM AUTHOR]

The paper reports the effect of mechanical activation of La 2 O 3 and Co 3 O 4 , the precursors for obtaining LaCoO 3 . The precursors were mechanically activated in a Fritsch Pulverisette 5 planetary mill for different durations (150 rpm). The optimal mechanical activation duration of the precursor powder is 10 h. The grain size distribution of the precursor powder at different grinding times was determined. The morphology of the powder was examined by scanning electron microscopy. Analysis by X-ray diffraction revealed that, for the synthesis of LaCoO 3 to take place, grinding alone is not enough, subsequent thermal treatment being crucial. The transformation of the mix in terms of its physical and chemical characteristics was carried out by thermal analysis. At the 10 h mechanical activation, the formation of LaCoO 3 was found to be fully completed at 1200 °C. However, at longer grinding times the reaction is fully completed only at 1250 °C. [ABSTRACT FROM AUTHOR]

Yttrium aluminum garnet (YAG) precursor precipitates, which were produced through bubbling ammonia gas approach, were solvothermally treated in alcoholic solution to synthesize monodispersed YAG powders in this paper. A variety of techniques, such as thermogravimetry/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the as-synthesized YAG precursor and powders. The results showed that the crystallization temperature of the YAG phase was largely dependent on the ethanol. Increasing the ethanol content in the solvent could decrease the YAG crystallization temperature. When the ratio of ethanol to water was 3:1, single-phase YAG was accurately available at a relatively lower temperature of 320 °C. Moreover, the obtained YAG powders were well-defined monodispersed spheres with mean particle size of about 274 nm, and showed excellent sinterability. [ABSTRACT FROM AUTHOR]

Yttrium aluminum garnet (YAG) precursor precipitates, which were produced through bubbling ammonia gas approach, were solvothermally treated in alcoholic solution to synthesize monodispersed YAG powders in this paper. A variety of techniques, such as thermogravimetry/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the as-synthesized YAG precursor and powders. The results showed that the crystallization temperature of the YAG phase was largely dependent on the ethanol. Increasing the ethanol content in the solvent could decrease the YAG crystallization temperature. When the ratio of ethanol to water was 3:1, single-phase YAG was accurately available at a relatively lower temperature of 320 °C. Moreover, the obtained YAG powders were well-defined monodispersed spheres with mean particle size of about 274 nm, and showed excellent sinterability. [ABSTRACT FROM AUTHOR]

Tremendous interest has been shown in the controllable synthesis and application of anatase TiO 2 nanomaterials with high percentage of reactive facets. In this work, ultrathin anatase TiO 2 nanosheets dominated by nearly 100% high-energy (001) facets were synthesized by using tetrabutyl titanate (TBT) and hydrofluoric acid (HF) as precursors. The morphological evolution of anatase TiO 2 nanosheets was studied by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM). As-prepared ultrathin TiO 2 nanosheets exhibited excellent photocatalytic activity toward the degradation of organic dye molecule rhodamine B (RhB) superior even to that of commercially available Degussa P25, due to the exposure of nearly 100% high-energy (001) facets and the effective suppression of recombination rates of photogenerated electrons and holes. These results demonstrate that the photocatalytic activity of anatase ultrathin TiO 2 nanosheets is highly dependent upon its exposed (001) facets, revealing important structure-property relationships in anatase TiO 2 nanosheets with specifically exposed (001) facets. The finding in this paper helps us further understand how shape variation, especially exposed (001) facets, influences the photocatalysis, it may also promote further development of anatase TiO 2 nanocrystals with tailored facets as well as the design and synthesis of other facet-exposed transition metal oxide nanomaterials. [ABSTRACT FROM AUTHOR]

Bismuth sulphide (Bi2S3)/reduced graphene oxide (RGO) composites were fabricated using facile single step process using d-pencillamine as a sulphur source. Fourier Transformer Infra Red spectroscopy (FT-IR), X-Ray Diffraction (XRD), Raman Spectroscopy, Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HR-TEM), and Electrochemical Impedance Spectroscopy (EIS) were employed to characterize and evaluate the properties of Bi2S3/RGO composites. This paper delivers a systematic investigation on the incorporation of the RGO on Bi2S3 microflowers for high efficiency visible light photocatalytic degradation of crystal violet dye (CV). As synthesized Bi2S3 microflower/RGO composites show tremendous improved photocatalytic performance than pure Bi2S3 microflowers. The superior photocatalytic activity of the Bi2S3/RGO composite was due to the enhanced light absorption, reduced recombination rate, and efficient charge transfer by incorporation of RGO. The degradation efficiency of Bi2S3/RGO 3% shows higher photocatalytic activity than pure Bi2S3 and commercialized TiO2. [ABSTRACT FROM AUTHOR]

The thermally grown oxide (TGO) at the interface of a ceramic-bond coating plays an important role in the failure of the thermal barrier coating (TBC). Therefore, it is important to control the growth of TGO to improve its service lifetime. In this paper an aluminum film was first deposited on the surface of atmospheric plasma sprayed TBC by direct current circular magnetron sputtering. Then the TBC samples with the aluminum film received a vacuum heat treatment. In situ synthesis of α-Al2O3 layer was observed at the top of the ceramic coating through the reaction of Al and ZrO2. The schematic diagram and thermodynamic mechanism of in situ synthesis of α-Al2O3 layer were presented. The cross sections of as-sprayed and treated TBCs were characterized by field emission-scanning electron microscopy (FE-SEM). Both phase structures were analyzed by X-ray diffraction (XRD) and transmission electron microscope (TEM) assisted with energy dispersive spectroscopy (EDS) and focused ion beam (FIB). Finally, oxidation resistance was compared between as-sprayed TBCs and vacuum treated TBCs and the average thickness of TGO was 4.89±0.53 and 2.52±0.47 µm correspondingly. [ABSTRACT FROM AUTHOR]

In this paper, TiO2/ZrO2 coaxial core-shell composite nanotubes were synthesized with the anodic aluminum oxide (AAO) template by a new "two-step method": Zr(NO3)4 sol was first deposited on the nanochannels of the AAO template to form a layer of ZrO2 nanotubes, and the TiO2/ZrO2 composite nanotubes were obtained after TiF4 sol was covered on the ZrO2 precursor. The process was suitable to produce large size and well-ordered nanotube arrays. The photocatalytic activities of the samples in AAO template were evaluated by the degradation of a model dye, methyl orange (MO). Compared with TiO2 nanotubes and ZrO2 nanotubes, the TiO2/ZrO2 composite nanotubes exhibited the better photocatalytic activity. Findings from this study suggested that TiO2 nanotube arrays with enhanced photocatalytic activity could be obtained, which opened a new pathway to construct nanostructured TiO2-based composite materials for photocatalytic applications. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, hydroxyapatite (HA) nano-rods have been successfully functionalized by depositing YVO4: Yb3+, Er3+ up-converting nanoparticles on the surfaces via a facile sol–gel technique. X-ray diffraction, field emission scanning electron microscopy, energy disperse X-ray spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectra were used to characterize the structure, morphology and up-conversion luminescent properties of the samples. The results indicate that the HA nano-rods have been successfully coated by YVO4: Yb3+, Er3+ up-converting nanoparticles, and the samples exhibit bright green up-conversion luminescence upon the excitation of a 980nm diode laser. Furthermore, the optical intensity of the composites can be controlled by varying the depositing cycles of YVO4: Yb3+, Er3+ up-converting nanoparticles. This up-conversion luminescent HA may find important applications in the fields of in vivo bio-imaging and a drug delivery system. [Copyright &y& Elsevier]

Abstract: In this paper, we report the hydrothermal synthesis, structural characterization and electrochemical properties of uniform α-Fe2O3 microspheres. In the synthetic procedure, the surfactant, sodium citrate, was found to be crucial to the formation of α-Fe2O3 microspheres. In addition, by simply varying the concentration of sodium citrate, cylindrical α-Fe2O3 microstructures could be readily obtained. On the basis of time-dependent experimental result, a possible formation mechanism of the α-Fe2O3 microspheres was proposed. The as-obtained α-Fe2O3 microspheres were then evaluated as an anode material for lithium ion batteries. And the result shows that the material exhibited an initial discharge capacity as high as 1453.4mAhg−1. After 50 cycles, the reversible discharge capacity was 489.5mAhg−1, which was much higher than that of commercial graphite. This work provides an additional strategy to prepare self-assembled structures with tailored morphology. And the results are helpful to further understand the mechanism of self-organization and expand the applications of iron oxide micromaterials. [Copyright &y& Elsevier]

Abstract: This paper focuses on the electrical properties of Bi0.95Nd0.05FeO3 thin films (BNFO05) deposited on Pt/TiO2/SiO2/Si (100) substrates by the soft chemical method. A BNFO05 single phase was simultaneously grown at a temperature of 500°C for 2h. Room temperature magnetic coercive field indicates that the film is magnetically soft. The remanent polarization (P r ) and the coercive field (E c ) measured were 51μC/cm2 and 65.0kV/cm, respectively, and were superior to the values found in the literature. XPS results show that the oxidation state of Fe is purely 3+, which is beneficial for producing a BNFO05 film with low leakage current. The polarization of the Au/BNFO05 on Pt/TiO2/SiO2/Si (100) capacitors with a thickness of 230nm exhibited no degradation after 1×108 switching cycles at a frequency of 1MHz. Experimental results demonstrated that the soft chemical method is a promising technique for growing films with excellent electrical properties, and can be used in various integrated device applications. [Copyright &y& Elsevier]

Abstract: In this paper copper selenide nanostructures were synthesized via a simple hydrothermal method based on the reaction between copper salt and SeCl4 in water. The reduction reaction of SeCl4 to Se and then Se2− was carried out by three types of reductants: N2H4.H2O, KBH4, and metallic Zn. Different compositions of copper selenides were obtained by changing the molar ratio of the precursors. At the temperature of 120°C for a 12h period of time, when the molar ratio of Cu/Se is 1:1 or 2:1, the product is pure and found to be CuSe and Cu1.8Se, respectively. A mixture of the different phases of copper selenides is obtained by making use of 1:2, 3:2 and 3:1M ratios between Cu and Se. With an increasing reaction temperature up to 210°C, the mixture of Cu3Se2 and CuSe is prepared from 1:1M ratio of precursors. The effects of copper salt, surfactant, amount of hydrazine, reaction time and temperature on the morphology and particle size of products are also investigated. The synthesis can be performed conveniently and safely. The products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. Photoluminescence (PL) is used to study the optical property of copper selenides. [Copyright &y& Elsevier]

Abstract: This paper reports the development of a new process for the synthesis and sintering of forsterite nanopowder via microwave-assisted high energy ball milling of a powder mixture containing silica gel and Mg(OH)2. X-ray diffraction (XRD), FTIR spectrometer, BET, scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) techniques were utilized to characterize the as-milled and annealed samples. X-ray diffraction results showed that highly ordered forsterite can be obtained through the calcination of the as-milled powder over 900°C. In addition, SEM and TEM observations of the synthesized powders showed that the particle size of the powder lies in the nanometer range, also being compared with the BET results (about 45 to 64.5nm). Microwave sintering (MS) of the forsterite nanopowder produced with high energy ball milling and subsequent microwave heating resulted in remarkable enhancement in densification in comparison with conventional sintering (CS) at lower temperatures. [Copyright &y& Elsevier]