O3 Powders Research Articles

Electrical and magnetic properties of 0–3 Ba(Fe1∕2Nb1∕2)O3/PVDF composites

Lead-free Ba(Fe[Formula: see text]Nb[Formula: see text]O3/PVDF 0–3 composites were fabricated using melt-mixing technique. X-ray diffraction, scanning electron microscopy, dielectric, impedance, ac conductivity, magnetic force microscopy (MFM) and vibrating sample magnetometer studies were undertaken to characterize the samples. Average crystallite size of the Ba(Fe[Formula: see text]Nb[Formula: see text]O3 powder, estimated using Williamson–Hall approach, was found to be [Formula: see text][Formula: see text]nm. The filler particles of [Formula: see text][Formula: see text][Formula: see text]m were found to disperse in the polymer matrix of all the composites. Filler concentration-dependent values of real and imaginary parts of complex permittivity showed increasing trend and were seen to follow Bruggeman and Furukawa equations. The data for ac conductivity exhibited negative temperature coefficient of resistance character of the test materials and were found to obey Jonscher’s power law. The correlated barrier hopping model was found to explain satisfactorily the mechanism of charge transport occurring in the system. MFM confirmed the presence of magnetic phases in the composites. Typical magnetization versus applied field curves indicated the possibility of magnetoelectric coupling in the system. Hence, the present composites have shown themselves as potential multi-functional candidate materials for use in high density data storage applications.

Influence of synthesis conditions on the crystal structure of the powder formed in the “HfO2 - CeO2/Ce2O3” system

Influence of synthesis conditions (type of atmosphere: reduction or oxidation, annealing temperature) on the chemical composition and structure of the compounds formed in the “HfO2 - CeO2/Ce2O3” system has been investigated by X-ray absorption fine structure spectroscopy combined with Raman spectroscopy, X-ray diffraction and thermogravimetric analysis. It was revealed that isothermal annealing of precursor at temperatures less than 1000°C in air leads to formation of Ce0.5Hf0.5O2 powders with cubic fluorite-type structure (space group Fm-3m). Further increase of annealing temperatures above 1000°C causes decomposition of formed crystal structure into two phases: cubic and monoclinic. Annealing in reduction hydrogen atmosphere causes formation of Ce4+2xCe3+2-2xHf2O7+x compounds with intermediate oxidation state of cerium, where value of x depends on the reducing conditions and treatment parameters. Annealing in vacuum at 1400°C strongly reduces the content of Ce4+ in a powder samples and leads to formation of pyrochlore structure (space group Fd-3m) with predominant +3 oxidation state of cerium.

Magnetic properties of BiFe0.93Mn0.07O3 powders obtained by ultrasonic spray pyrolysis

Samples of BiFe0.93Mn0.07O3 with different specific surface area were synthesized for the first time by ultrasonic spray pyrolysis. The resulting powders consist of porous particles of a spherical shape of medium size ~0.5 μm and have record values of residual magnetization and coercive force. It is found that the magnetic properties of the porous powder particles are determined by the distortion of the crystal lattice and the presence of uncompensated magnetic moments of iron ions on the surface.

Reaction of hydrogen peroxide with uranium zirconium oxide solid solution – Zirconium hinders oxidative uranium dissolution

We studied oxidative dissolution of uranium and zirconium oxide [(U,Zr)O2] in aqueous H2O2 solution to estimate (U,Zr)O2 stability to interfacial reactions with H2O2. Studies on the interfacial reactions are essential for anticipating how a (U,Zr)O2-based molten fuel may chemically degrade after a severe accident. The fuel's high radioactivity induces water radiolysis and continuous H2O2 generation. Subsequent reaction of the fuel with H2O2 may oxidize the fuel surface and facilitate U dissolution. We conducted our experiments with (U,Zr)O2 powder (comprising Zr:U mole ratios of 25:75, 40:60, and 50:50) and quantitated the H2O2 reaction via dissolved U and H2O2 concentrations. Although (U,Zr)O2 reacted more quickly than UO2, the dissolution yield relative to H2O2 consumption was far less for (U,Zr)O2 compared to that of UO2. The reaction kinetics indicates that most of the H2O2 catalytically decomposed to O2 at the surface of (U,Zr)O2. We confirmed the H2O2 catalytic decomposition via O2 production (quantitative stoichiometric agreement). In addition, post-reaction Raman scattering spectra of the undissolved (U,Zr)O2 showed no additional peaks (indicating a lack of secondary phase formation). The (U,Zr)O2 matrix is much more stable than UO2 against H2O2-induced oxidative dissolution. Our findings will improve understanding on the molten fuels and provide an insight into decommissioning activities after a severe accident.

Magnetic, optical, dielectric, and sintering properties of nano-crystalline BaFe0.5Nb0.5O3 synthesized by a polymerization method

A one-pot polymerization method using citric acid and glucose for the synthesis of nano-crystalline BaFe0.5Nb0.5O3 is described. Phase evolution and the development of the crystallite size during decomposition of the (Ba,Fe,Nb)-gel were examined up to 1100 °C. Calcination at 850 °C of the gel leads to a phase-pure nano-crystalline BaFe0.5Nb0.5O3 powder with a crystallite size of 28 nm. The shrinkage of compacted powders starts at 900 °C. Dense ceramic bodies (relative density ≥ 90%) can be obtained either after conventional sintering above 1250 °C for 1 h or after two-step sintering at 1200 °C. Depending on the sintering regime, the ceramics have average grain sizes between 0.3 and 52 µm. The optical band gap of the nano-sized powder is 2.75(4) eV and decreases to 2.59(2) eV after sintering. Magnetic measurements of ceramics reveal a Neel temperature of about 23 K. A weak spontaneous magnetization might be due to the presence of a secondary phase not detectable by XRD. Dielectric measurements show that the permittivity values increase with decreasing frequency and rising temperature. The highest permittivity values of 10.6 × 104 (RT, 1 kHz) were reached after sintering at 1350 °C for 1 h. Tan δ values of all samples show a maximum at 1–2 MHz at RT. The frequency dependence of the impedance can be well described using a single RC-circuit.

Effect of zirconia on the structural and optical properties of strontium titanate ceramic

ABSTRACTSr(ZrxTi1-x)O3 (SZT) powders were prepared by using a planetary ball milling unit. Compositionally induced phase transitions in SZT system were analysed using a combination of X-ray diffraction and FT-Raman. The system showed two tilting of phase transitions, pm3m–I4mcm and I4/mcm–pnma. The optical band gap of the system was calculated from the reflectance data recorded from a UV-Vis spectrometer using Kubelkae-Munk equation. The width of defect bands (Urbach energy) was determined from the reflectance data. The optical band gap increased from 3.04 eV to 5.13 eV with increase of x content. The Photoluminescence analysis of all compositions showed Violet-blue-green emission.

Crystal Structure Analysis and Mg Battery Cathode Properties of Delithiated Li1-XNi0.5Mn0.5O2 with Layered Rock-Salt Structure

Introduction Recent interest in the magnesium rechargeable batteries may be attributed both to their technological potential and to the fact that they represented an intercalation mechanism of magnesium into the oxide materials. The chevrel compound, Mo6S8, has been attracted much attention because of its high reversibility and excellent cycle life. The low stability and capacity, however, have led to the investigation of alternative materials. So far, the delithiated Li compounds, LiFePO4 and Li3V2(PO4)3, have been studied to show high specific capacities of about 300 mAh g-1 and 200 mAh g-1, respectively. Although the theoretical capacity of delithiated Li1-xNi0.5Mn0.5O2 exceed 500 mAh g-1, the examination of the use as the cathode of magnesium rechargeable battery has not been performed. The synthesis of delihitated Li1-xNi0.5Mn0.5O2 has opened route for the electrochemically or chemically delihiated methods [1]. The advantage of such an electrochemically method is to control the deilthiation amount whereas a chemically method is to obtain the delithiated sample without the additives such as conductive carbon and PTFE binders. In this study, the delithiated Li1-xNi0.5Mn0.5O2 was synthesized and analyzed about the crystal structures and valence states of Ni and Mn before and after magnesiation. Experimental The LiNi0.5Mn0.5O2 was synthesized via a traditional solid-state reaction route. The LiOH·H2O, NiO and MnO2 were thoroughly mixed by planetary ball milling. The obtained powders were heated at 600 °C in air for 5 hours and then pressed into a pellet to calcine at 1000 °C in air for 10 hours. The delithiated Li1-xNi0.5Mn0.5O2 was prepared by electrochemical method and chemical one using NO2BF4 oxidizer. The LiNi0.5Mn0.5O2 powders were stirred in NO2BF4 solution in acetonitrile for 12 hours. When the reaction was completed, the solution was filtered and washed with acetonitrile. Chemical analyses for Li, Ni and Mn were carried out by inductively coupled plasma atomic emission spectroscopy (ICP-AES) to evaluate the delithiation amounts. Powder X-ray diffraction data were collected on a Panalytical X’pert-pro diffractometer. The morphology was observed by scanning electron microscopy (SEM, Hitachi, S-2600N). The crystal structure analysis was performed by using the synchrotron X-ray diffraction at BL19B2 (SPring-8, JAPAN). The valence states of Ni and Mn before and after magnesiation were examined by the XAFS at BL14B2 (SPring-8, JAPAN). Discharge and charge tests were performed at 60 °C using a positive electrode, which consisted of the delithiated Li1-xNi0.5Mn0.5O2, conductive carbon, and poly-tetrafluoroethylene powder between 0.5 and 3.0 V using an Mg-alloy negative electrode at a fixed current density of 5 mA g-1. A solution of 0.5 M Mg(TFSI)2 in a acetonitrile (Kishida Chemical Co., Ltd.) was used as the electrolyte. The cells were constructed in an argon-filled globe box. Results and Discussion The XRD pattern for the pristine LiNi0.5Mn0.5O2 was attributed to the ordered rock-salt structure with R-3m space group. The electrochemically delithiated Li0.1Ni0.5Mn0.5O2 was transformed to different layered structure. On the other hand, the chemically delithiation of LiNi0.5Mn0.5O2 resulted in the only peak shift of the XRD while retaining the original structure. The cathode performance of electrochemically delithiated Li0.1Ni0.5Mn0.5O2 showed about 35 mAh g−1 at first and second discharges (Fig.). Although the first charge capacity was too large for first discharge, the agreement of the discharge capacities at first and second cycles indicated to demagnesiate from the magnesiated MgxLi0.1Ni0.5Mn0.5O2 at first charge. The synchrotron X-ray diffraction patterns of pristine and delithiated and magnesiated samples were analyzed by Rietveld method and were not fully fitted to the layered rock-salt structure for delithiated and magnesiated those. The refined lattice parameters showed to intercalate the magnesium in the Li0.1Ni0.5Mn0.5O2. In addition the XANES spectra of the pristine and delithiated and magnesiated samples were measured to show the valence change corresponding to the delithiation and magnesiation. Reference [1] N. Ishida, N. Tamura, N. Kitamura, and Y. Idemoto, J. Power Sources, 319, 255 (2016) Figure 1

Influence of the Charge/Discharge Voltage Range on the Capacity Reversibility and Electrode/Electrolyte Interface Stability of LiCo1/3Ni1/3Mn1/3O2

Introduction Many attempts have been made to increase the energy density of Li-ion batteries using positive electrode materials such as LiMO2 (LiCoO2, LiNiO2, LiNi1/3Mn1/3Co1/3O2, etc.), which have high charging voltages (typically ≥4.4 V). Various studies to understand the associated degradation mechanism and improve the capacity reversibility during high-voltage charge/discharge have been reported. Generally, the inter-terminal voltage of Li-ion batteries can be practically controlled by changing the electric potential of the positive electrode. Thus, the positive electrodes used for high-voltage charge/discharge are exposed to a high electric potential as well as a large change in the electric potential. In this study, we examined the influence of the operating voltage range on the charge/discharge characteristics, and found that the discharge cutoff voltage greatly influences the capacity reversibility during high-voltage charge/discharge. Additionally, we discuss the mechanisms that determine the capacity reversibility based on the results of electrochemical impedance analysis and soft X-ray absorption spectroscopy (soft XAS). Experimental LiNi1/3Co1/3Mn1/3O2 powder, with a secondary particle diameter of 10 μm (Toda Kogyo Corp.), was used as the active material. Positive electrodes were fabricated from a mixture of 90 wt% LiNi1/3Co1/3Mn1/3O2, 5 wt% acetylene black, and 5 wt% polyvinylidene fluoride. The electrochemical characteristics of the samples were examined in coin cells with a Li-metal counter electrode. A 1.0 mol dm-3 solution of LiPF6 in ethylene carbonate + diethyl carbonate was used as the electrolyte. The cells were cycled at discharge-charge cutoff voltages of 2.5–4.6, 3.0–4.6, 3.8–4.6, and 4.2–4.6 V, at a current rate of 1 C. The Li-ion transfer characteristics were measured by alternating current impedance spectroscopy. The electronic structure of the LiNi1/3Co1/3Mn1/3O2was investigated using soft XAS at the beam line BL11 of Ritsumeikan University SR Center (Shiga, JAPAN). Results and Discussion Figures 1a and b show the discharge capacity and discharge capacity retention versus cycle number for LiNi1/3Co1/3Mn1/3O2 cycled with different voltage ranges. As the discharge cutoff voltage was increased, the initial discharge capacity decreased, accompanied by an improvement in the discharge capacity retention. The retentions at the 143rd cycle for LiNi1/3Co1/3Mn1/3O2cycled with 2.5–4.6, 3.0–4.6, 3.8–4.6, and 4.2–4.6 V, were 8, 37, 56, and 81%, respectively. Figure 2a shows the Nyquist plots for LiNi1/3Co1/3Mn1/3O2 cycled with different voltage ranges at an open circuit voltage of ~4.2 V after 3 cycles. The charge transfer resistances (R ct) calculated from the semicircles in the lower frequency region were almost equal (5–8 Ω) regardless of the discharge cutoff voltage. From the Nyquist plots after 143 cycles (Figure 2b), the R ct for LiNi1/3Co1/3Mn1/3O2 cycled with 2.5–4.6, 3.0–4.6, 3.8–4.6, and 4.2–4.6 V, were obtained as 3800, 300, 65, and 17 Ω, respectively. The increase of R ct with the number of cycles was significantly suppressed as the discharge cutoff voltage was increased, resulting in the higher capacity retention observed in Fig. 1b. These results suggest that a stable interface is retained between the electrode and electrolyte when the charge/discharge voltage is limited to the high-voltage region only. The interface structure and the capacity reversibility mechanism will be discussed along with the electronic state of LiNi1/3Co1/3Mn1/3O2analyzed by soft XAS. Acknowledgements This work is financially supported by the RISINGII project of the NEDO and METI, Japan. Figure 1

Effect of Ho, Mn co-doping on the structural, optical and ferroelectric properties of BiFeO3 nanoparticles

Multiferroic Bi1 − xHoxFe0.95Mn0.05O3 (x = 0.025, 0.05, 0.075, 0.10 and 0.1) powder samples were successfully prepared by sol–gel technique. The effect of Ho, Mn co-doping on the properties of structural, electrical, optical and ferroelectric have been systematic investigated. X-ray diffraction (XRD) patterns reveal that Ho, Mn co-substitution leads to a structural transition. The scanning electron microscope (SEM) shows that the grains of all the samples are asymmetrical and anomalous in shape and the particle size of the samples decrease from 200 to 500 to ~100 nm with doping Ho and Mn in BFO. UV–Visible absorption spectra exhibit that co-doping can reduce the direct optical band gap from 2.40 to ~1.77 eV after doping Ho and Mn. Electric measurements demonstrate that both of the leakage current density and ferroelectric properties can be improved obviously by Ho and Mn co-doping as a result of the suppression of oxygen vacancies.

Enhanced electrochemical property of FePO4-coated LiNi0.5Mn1.5O4 as cathode materials for Li-ion battery

Pristine LiNi0.5Mn1.5O4 and FePO4-coated one with Fd-3m space groups were prepared by a sol-gel method. The structure and performance were studied by X-ray diffraction (XRD) rietveld refinement, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy dispersive spectrometer (EDS) mapping, electrochemical impedance spectroscopy (EIS) and charge-discharge tests, respectively. The lattice parameters of all samples almost remain the same from the Rietveld refinement, revealing that the crystallographic structure has no obvious difference between pristine LiNi0.5Mn1.5O4 and FePO4-coated one. All materials show similar morphologies with uniform particle distribution with small particle size, and FePO4 coating does not affect the morphology of LiNi0.5Mn1.5O4 material. EDS mapping and HRTEM show that FePO4 may be successfully wrapped around the surfaces of LiNi0.5Mn1.5O4 particles, and provides an effective coating layer between the electrolyte and the surface of LiNi0.5Mn1.5O4 particles. FePO4 (1wt%)-coated LiNi0.5Mn1.5O4 cathode shows the highest discharge capacity at high rate (2C) among all samples. After 80 cycles, the reversible discharge capacity of FePO4 (1wt%) coated LiNi0.5Mn1.5O4 is 117mAhg−1, but the pristine one only has 50mAhg−1. FePO4 coating is an effective and controllable way to stabilize the LiNi0.5Mn1.5O4/electrolyte interface, and avoids the direct contact between LiNi0.5Mn1.5O4 powders and electrolyte, then suppresses the side reactions and enhances the electrochemical performance of the LiNi0.5Mn1.5O4.

LaNi0.6Fe0.4O3 as Cathode Contacting Material: Effect on Anode Supported Cell Performances

In planar solid oxide fuel cell (SOFC) stacks ohmic losses are introduced at the interface between the electrodes and current collectors, especially in the cathodic compartments, due to the contact inhomogeneity. The porosity of the electrodes and geometrical issues linked to the shape of the interconnects are factors resulting in the reduction of the contact surface between such components. Contacting layers are often applied between the cathode and the interconnect in order to minimize such issues ensuring a uniform current collection along the electrode area. This leads to proper operation of the cells increasing the performances in terms of power output and mitigating their degradation rate. In this work, LaNi0.6Fe0.4O3 (LNF) powders have beensynthesized by sol-gel methods and used to prepare a contacting paste. A testing setup, developed to test anode-supported cells with different contacting geometries, has been used to investigate the effect of LNF contacting paste between the cathode and the current collector. The cell performances revealed comparable results compared to those measured using a state-of-art La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) contacting paste, even showing better stability over time. Cell performances have been investigated by means of current-voltage curves. Electrochemical impedance spectroscopy has been used to distinguish the loss contribution within the investigated system and to measure their evolution over time. To confirm the observed performance evolution, microstructural changes and migration of elements have been characterized post-experiment by means of scanning electron microscopy-energy dispersive X-ray and X-ray diffraction techniques.

Surface Modification of a Li[Ni0.8Co0.15Al0.05]O2 Cathode using Li2SiO3 Solid Electrolyte

Li2SiO3 was used as a coating material to improve the electrochemical performance of Li[Ni0.8Co0.15Al0.05]O2. Li2SiO3 is not only a stable oxide but also an ionic conductor and can, therefore, facilitate the movement of lithium ions at the cathode/electrolyte interface. The surface of the Li2SiO3-coated Li[Ni0.8Co0.15Al0.05]O2 was covered with island-type Li2SiO3 particles, and the coating process did not affect the structural integrity of the Li[Ni0.8Co0.15Al0.05]O2 powder. The Li2SiO3 coating improved the discharge capacity and rate capability; moreover, the Li2SiO3-coated electrodes showed reduced impedance values. The surface of the lithium-ion battery cathode is typically attacked by the HF-containing electrolyte, which forms an undesired surface layer that hinders the movement of lithium ions and electrons. However, the Li2SiO3 coating layer can prevent the undesired side reactions between the cathode surface and the electrolyte, thus enhancing the rate capability and discharge capacity. The thermal stability of Li[Ni0.8Co0.15Al0.05]O2 was also improved by the Li2SiO3 coating. Keywords: Surface coating, Cathode, Lithium battery, Solid electrolyte

Studying effect of Zr concentration on the properties of Pb(Zrx,Ti1-x)O3 /n-Si and Pb(Zrx,Ti1-x)O3 /n-PS Photodetectors prepared by pulsed laser deposition (PLD)

Pb(Zrx,Ti1-x)O3 (PZT) powder was prepared via solid-state reaction and deposited on n-type silicon wafers ( Pb(Zrx,Ti1-x)O3/n-Si ) and on n-type porous silicon ( Pb(Zrx,Ti1-x)O3/n-PS ) of (111) orientation and (0.015 Ω.cm) resistivity by (PLD). We used the photoelectrochemical etching cell for creation the porosity layers on the silicon wafers. Using thermal evaporation system to evaporate Al on the back of the wafer to make an ohmic contact thick film. Spectral measurements ( responsivity, quantum efficiency, detectivity and noise equivalent power ) for Pb(Zrx,Ti1-x)O3 /n-Si and Pb(Zrx,Ti1-x)O3 /n-PS devices show ( 1.2482, 0.4422% , 2.207×1010 and 0.45×10-10 ) and ( 1.5695, 0.5561%, 2.618×1010 and 0.36×10-10 ) respectively. the favorite x content of Zr is 0.5 for all samples. spectral parameters for devices assign to the stable behavior of the samples after etching procedure and its values are larger than that for without porous

Fabrication of BaZr1-XYxO3 Powder by Freeze Drying Method

Reduction of the synthesizing temperature of BaZr1-xYxO3 powder was tried by freeze drying method. Nitrates were chosen as raw materials and the nitrate mixture desiccated by freeze drying method was reacted at 600 ~ 1000 oC to produce BaZr1-xYxO3 powder. Nitrogen atmosphere was chosen as a reaction atmosphere to prevent production of BaCO3. Crystal structure and composition of the synthesized powder were measured by X-ray diffraction method (XRD) and energy-dispersive X-ray spectroscopy (EDX), respectively. It is clarified that BaZr0.8Y0.2O3 powder whose particle size was several mm could be synthesized at more than 800 oC by controlling composition of the nitrate mixture.

LaNi0.6Fe0.4O3 as Cathode Contacting Material: Effect on Anode Supported Cell Performances

In this work, LaNi0.6Fe0.4O3 (LNF) powders have been synthesized by sol-gel methods and used to prepare a contacting paste. A testing setup, developed to test anode-supported cells with different contacting geometries, has been used to investigate the effect of LNF contacting paste between the cathode and the current collector. The cell performances were comparable to those measured using a state-of-the-art La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) contacting paste, however, showing better stability under electric load. Cell performances have been investigated by means of current-voltage curves. Electrochemical impedance spectroscopy has been used to distinguish the loss contribution within the investigated system and to measure its evolution over time. The performances evolution was confirmed by microstructural changes and migration of elements characterized post-experiment by means of scanning electron microscopy-energy dispersive X-ray and X-ray diffraction techniques.

Preparation of yttria powders co-doped with Nd3+, and La3+ using EDTA gel processes for application in transparent ceramics

The aim of the work was to synthesize Y2O3, La0.1Y1.9O3, Nd0.1Y1.9O3, Nd0.1La0.1Y1.8O3 and Nd0.12La0.1Y1.78O3 powders using EDTA gel processes, and to examine the physicochemical properties of transparent sinters obtained from these powders. A part of this goal was the determination of the influence of various dopants on the optical properties of yttria. X-ray diffraction studies of the investigated powders and sinters confirmed their single-phase composition, which indicated incorporation of lanthanum and neodymium into the crystal lattice of yttria. Scanning electron microscopy (SEM) combined with density measurements indicated that the studied sinters had high density. An optical transparency over 50% was obtained for the Y2O3 sinter in the wavelenght range of 450–1100nm. The influence of dopants on the level of transmittance was also investigated.

Solid-state synthesis of nano-sized Ba(Ti1−x Sn x )O3 powders and dielectric properties of corresponding ceramics

Powders of a few compositions of solid solution BaTi1−x Sn x O3 (x = 0.0, 0.1, 0.2, 0.3 and 0.40) have been synthesized at 800 °C for 8 h using Ba(NO3)2, TiO2 and SnCl4·5H2O as starting materials. The thermogravimetric (TG) and differential scanning calorimetric (DSC) analysis of mixture in the stoichiometric proportion for sample BaTi0.80Sn0.20O3 have been carried out to understand the formation of solid solutions. Single-phase pure compounds (except x = 0.40) of the samples have been obtained at a lower calcination temperature (800 °C) than that of those reported in the literature for traditional solid-state synthesis making use of oxides and or carbonates as starting material (≥1200 °C). Tetragonal symmetry for compositions x = 0.0 and 0.10, cubic for x = 0.2 and 0.30 were found by X-ray diffraction (XRD) analysis. The transmission electron microscopic (TEM) analysis confirmed that calcined powders have a particle size between 30 and 50 nm. Ceramics of these powders were prepared by sintering at 1350 °C for 4 h. Properties of ceramics obtained in this work have been compared with properties reported in the literature.

Homogeneous (Lu1 − xInx)2O3 (x = 0 − 1) solid solutions: Controlled synthesis, structure features and optical properties

A series of (Lu1−xInx)2O3 (x=0–1) powders have been synthesized by a facile co-precipitation route using ammonium hydrogen carbonate (AHC) as the precipitant. The effects of In3+ substitution for Lu3+ on the particle properties, structure features and optical performances of the materials were systematically investigated. The results show that (1) the (Lu1−xInx)2O3 precursor samples with x=0–0.5 possess a chemical composition of basic carbonate, however, the precursor specimen with x=1 is hydrated oxyhydroxide; (2) In3+ addition significantly affects the nucleation kinetics of the binary Lu–In system, leading to the empty interiors inside the precursors; (3) calcining the resultant precursors directly yields well-dispersed (Lu1−xInx)2O3 oxide particles with ultrafine sizes of ~65nm; (4) both the lattice parameters and theoretical densities of the solid solutions linearly decrease along with increasing In3+ incorporation; (5) In3+ doping apparently red-shifts the absorption edge of UV–vis absorption spectroscopy and the bandgap energies of the (Lu1−xInx)2O3 oxide powders generally decrease at a higher In3+ content.

Mechanical activation and electrophysical properties of Pb(Zr0.58Ti0.42)O3

The influence of mechanical force action combined with shear deformation implemented via Bridgman anvils on the dielectric properties of synthesized Pb(Zr0.58Ti0.42)O3 powder is studied. It is ascertained that the physical properties of sintered ceramics can be controlled over a wide range upon varying the concentration and type of structural defects arising from the mechanical activation of powders.

Synthesis, characterization and degradation activity of Methyl orange Azo dye using synthesized CuO/α-Fe2O3 nanocomposite

This study investigated the photo-degradation of methyl orange (MO) as a type of azo dye using a CuO/α-Fe2O3 nanocomposite. A CuO/α-Fe2O3 powder with a crystalline size in the range of 27-49 nm was successfully prepared using simple co-precipitation along with a sonication method. The characterization of the synthesized sample was done via XRD, FE-SEM, EDS, FTIR and DRS analyses. The Tauc equation revealed that the band gap of the nano composite in the direct mood was 2.05 ev, which is in the visible light range. The effect of operating factors containing dye concentration, photocatalyst dosage and pH on dye degradation efficiency was measured. Response Surface Method (RSM) was employed to specify the parameter effects. The photocatalytic activity of the CuO/α-Fe2O3 nanocomposite was evaluated by degradation of MO under visible light irradiation. The results showed that the pH value played a very effective role in the dye degradation process efficiency. Also, the photocatalytic degradation of MO obtained was equal to 88.47% in the optimal values.