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Pyramid-like magnetite crystals are assembled via a simple one-pot hydrothermal process with industrialized environmental free raw materials. It is revealed that these crystals have hierarchical structures which are self-assembled of nano-sized ultrafine magnetite spheres. The electrochemical properties of the as-prepared magnetite are studied by galvanostatic cell cycling at different current rates. The electrodes exhibit high reversible specific capacity (about 1600 mA h g −1 at 40 mA g −1 ) at low rate and good cycle property at 1 C. The specific capacity increases after it reaches a minimum, which is believed to be related to the formation of SEI film. After cycled 500 times at 1 C, the reversible capacity is still higher than 340 mA h g −1 .

Mesoporous α-LiAlO 2 powders have been successfully prepared by a hydrothermal route based on using the surfactant CTAB as the template. The structure and morphology of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The crystallization transition process of the precursor after hydrothermal reaction was investigated by thermal gravity analysis. The prepared lithium aluminate had a morphology of two-dimensionally mesoporous nanoflakes with single crystal structure. A high specific surface area up to 124 m 2 /g was obtained by this method.

An a.c. powder electroluminescent (EL) device using ZnGa 2 O 4 :Cr 3+ phosphor was fabricated by the screen printing method. Optical and electrical properties of the device were investigated. The fabricated device shows a red emission at 695 nm driven by the a.c. voltage. The emission is attributed to the energy transfer from hot electrons to Cr 3+ centers via self-activated Ga–O groups. Luminance ( L ) versus voltage ( V ) matches the well-known equation of L = L 0 exp(− bV − 1 / 2 ) and luminance increases proportionally with frequency due to the increase of excitation probability of host lattice or Cr 3+ centers. The diagram of the charge density ( Q ) versus applied voltage ( V ) is based on a conventional Sawyer–Tower circuit. At 280 V and 1000 Hz, the luminance and the luminous efficiency of the fabricated powder EL device are about 1.0 cd/m 2 and 13 lm/W, respectively. And under the high field, the device fabricated with the oxide-based phosphor of ZnGa 2 O 4 :Cr 3+ shows excellent stability in comparison with the conventional sulfide powder EL device.

The aim of the present work was to identify the conditions for the preparation of stable zirconia slurries with high solids content for the production of aqueous gel tape casting objects with improved properties. Influences of the powder and dispersant on the rheological properties were investigated. High stable low-viscosity nanoparticles zirconia suspensions were achieved. Nanometer-sized tetragonal polycrystal zirconia powder was synthesized by a new low-temperature environment-benign method. The oxide powders were confirmed to be 3Y-TZP single phase with tetragonal structure measured by X-ray diffraction analysis. Acryl amide (AM) and N,N′-methylene bisacrylamide (MBAM) have been used as organic monomer and cross-linker of the process, respectively. NH4PAA (M=5000–8000) has been used as polyelectrolyte dispersant. The electrokinetic behavior of nanometer-sized zirconia suspensions stabilized by various dispersant contents was studied. The result indicated the dispersant concentration greatly affected the surface charge of nanometer tetragonal zirconia powder. The isoelectric point (IEP) obviously changed from 8.1 to about 4.7 because of the addition of polyelectrolyte dispersant. To acquire stable low-viscosity slurries, the influences of several parameters on rheological behavior of nanosized tetragonal zirconia suspensions were investigated. It was found that for each factor, there exists an optimum range in which low viscosity was achieved for a slurry with high solid loading. For the slurry of 77 wt.% powder concentration with about 1.0 wt.% polyelectrolyte (based on the powder), the viscosity was 350 mPa s at the shear rate of 110 s−1. The slurry at the optimum conditions met the demands of aqueous gel tape casting process.

Oil flotation is a separation process that has widely been utilized in the separation and purification of minerals from raw ores. In the current study, this process was combined with coprecipitation process to prepare nanosized 8 mol% yttria-stabilized zirconia (8YSZ) powder. One of the most attractive characteristics of the oil flotation-assisted process is that highly hydrophilic hydroxide precipitate can be transformed to hydrophobic and directly be extracted from aqueous phase to oil phase with the help of SPAN80 (flotation reagent). After laundering with water, the precipitate was dried to recover oil and fired to oxide at 800 °C.

Sr 4 Al 14 O 25 –Eu,Dy photoluminescent material with high brightness and long afterglow was prepared by sintering at high-temperature and weak-reducing atmosphere. The luminescent properties of Sr 4 Al 14 O 25 -based luminescent materials have been studied systematically. The analytical results indicated that the emission spectra of Sr 4 Al 14 O 25 –Eu,Dy are similar to that of Sr 4 Al 14 O 25 –Eu. Both of them have two main peaks near 424 and 486 nm, respectively, which are ascribed to two types of Eu 2+ that existed in the Sr 4 Al 14 O 25 matrix crystal. However, the Sr 4 Al 14 O 25 –Eu phosphor does not have the long-afterglow phenomenon; the Sr 4 Al 14 O 25 –Eu,Dy showed the obvious long afterglow. As for the mechanism of the long afterglow of this phosphor, Dy 3+ acted as the trap level and captured the free holes in the system. It is the trapped–detrapped recombination process that resulted in the long-afterglow phenomenon of this phosphor.

A ZrO 2 -based electrolyte, stabilized with 6 mol% CaO and 4 mol% Y 2 O 3 was synthesized. This electrolyte consists of a single phase fluorite-type solid solution with cubic symmetry and exhibits a uniform microstructure. In the temperature range 1273–1673 K, the direct current (DC) conductivity of this electrolyte is higher than that of 12 mol% CaO-stabilized ZrO 2 and comparable to that of 8 mol% Y 2 O 3 -stabilized ZrO 2 , prepared with the same processing procedure. It was suggested, by comparing the electrical behaviors of both binary systems ZrO 2 –CaO and ZrO 2 –Y 2 O 3 , that the enhancement of the ionic conductivity of mixed CaO/Y 2 O 3 -stabilized ZrO 2 at high temperature can be attributed to the increase in the concentration of the oxygen vacancies with weaker association energies.