We estimated site potentials for respective Li ions in the unit cell of Li4SiO4 crystal structure using the VESTA program and examined relation between the estimated site potentials and reactivity of the respective Li ions to CO2. Values of the estimated site potentials for the respective Li ions were distributed over a range of the shallowest level (−11.6 V) to the deepest level (−17.3 V). It is forecasted that the depth of these potentials would relate with reaction between CO2 and the respective Li ions in the unit cell of the Li4SiO4 crystal structure.
Heterostructure Ag3PO4/Bi2MoO6 nanocomposites were synthesized by a deposition–precipitation method at high temperature and pressure. The as-synthesized products were characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. In this research, cubic Ag3PO4 nanoparticles were deposited on orthorhombic Bi2MoO6 nanoplates. For 10.0 wt % Ag3PO4 loading, the Ag3PO4 nanoparticles with 5–10 nm in size were detected across the surface of Bi2MoO6 nanoplates. The effect of Ag3PO4 content on the photocatalytic properties was investigated by evaluating the degradation of rhodamine B under visible white light. The Ag3PO4/Bi2MoO6 nanocomposites exhibited more enhanced photocatalytic activity than the pure Bi2MoO6. Electron–hole diffusion in Ag3PO4/Bi2MoO6 nanocomposites and photodegradation mechanism of rhodamine B were also discussed in this report.
The development of a fabrication process for sheet-type all-solid-state batteries with high energy density is critical for industrial applications. In this study, we systematically investigate the fabrication process of cells using composite positive electrode sheets with a high ratio of active materials. n-Decane was selected as a suitable solvent for the slurry because it has a sufficiently low vapor pressure and does not affect the ionic conductivity of solid electrolytes. In addition, the pre-densification of the composite positive electrode sheets was found to be effective in improving the cell performance. Suitable fabrication pressures were also determined. The cells fabricated under low-pressure conditions exhibited higher discharge capacities despite the higher internal resistance. Finally, our study revealed that the fracturing of LiNi1/3Co1/3Mn1/3O2 (NCM) occurs under high-pressure fabrication conditions because of the compression between the closely located NCM particles, resulting in the cleavage of the ionic and electronic conduction pathways.
Bi2−xZr3x/4O3 solid solutions were synthesized by conventional ceramic method and their color properties were investigated as environment-friendly inorganic orange pigments. Single phased Bi2−xZr3x/4O3 solid solutions with tetragonal crystal structure are formed in the range of 0.3 ≤ x ≤ 0.5 compositions. Brilliant orange color powders were obtained for x = 0.5 composition heated at 800°C, which had color parameters (L*, a*, b*) of L* = 68, a* = 34, and b* = 69. The color of x = 0.5 samples is comparable to that of orange color specified in Japanese Industrial Standards (JIS) for a traffic paint. Since Bi2−xZr3x/4O3 solid solutions are composed of nontoxic elements, it should be an alternative candidates to conventional PbCrO4-based pigments for traffic paint.
In this study, we successfully synthesized SrAlSiN3:Ce3+ at 1073 K using the ammonothermal method. Scanning electron microscope images revealed bar-like crystals in the products. We investigated the effects of using a charge-compensating ion on the phosphor’s emission of SrAlSiN3 with Ce3+ and Sr2+ and adding Na+ as a charge compensator. We found that Ce3+-doped SrAlSiN3 exhibited a weak emission. However, SrAlSiN3 co-doped with Ce3+ and Na+ exhibited a broad emission band centered at approximately 550 nm for an excitation wavelength of 460 nm. We, thus, found that Na+ has an important impact on Sr2+ and Ce3+ by acting as a charge-compensating ion. We were able to successfully synthesize a novel SrAlSiN3:Ce3+ phosphor by adjusting the charge of Sr2+ and Ce3+ by controlling the Na+ co-doping.
Graphite waste from primary batteries, active yeast and commercial rice husk ash have been used as pore-forming agents to fabricate porous alumina ceramics using a fugitive materials technique. The pore-forming agent ratios were between 10 to 50 wt %. The effects of the pore-forming agent ratios on the mechanical properties, the porosity and the microstructure have been investigated in this study. The results showed that through increasing the pore-forming agent ratio for graphite waste, yeast and rice husk ash, the porosity increased from 37.3 to 61.1%, 30.2 to 63.8% and 42.9 to 49.0%, respectively. The hardness also decreased from 172.6 to 38.1 HV1 and from 160.6 to 15.0 HV1 for porous alumina ceramics using graphite waste and yeast as pore-forming agents, respectively. However, the hardness of the porous alumina ceramics with rice husk ash as a pore-forming agent increased at 30 wt % (150.9 HV1) and 50 wt % (158.9 HV1). The tensile strength for porous alumina ceramics using graphite waste and yeast as pore-forming agents decreased from 24.9 to 14.3 MPa and from 26.2 to 5.4 MPa. The compressive strength decreased from 112.3 to 34.3 MPa and from 19.5 to 1.8 MPa, respectively. However, for porous alumina ceramics using rice husk ash, the tensile strength increased at 30 wt % (24.1 MPa) and 50 wt % (21.9 MPa). The compressive strength also increased at 30 wt % (69.7 MPa) and at 50% (60.1 MPa).
The sintering of hardly sintered TiB2 powder has been investigated using the spark plasma sintering (SPS) technique. The investigation revealed that TiB2 powder can be sintered to highly dense bulk samples using SPS technique. However optimization of the sintering condition could not generate bulk samples with a fine microstructure. The addition of TiN was found to be effective in obtaining bulk samples with fine structure. Sample bending strength largely improved from 120 MPa for TiN free samples to more than 373 MPa, much higher than that of graphite, for TiN containing samples. The improvement in bending strength is attributed to the fine structure formed and to the strong bonding between TiB2 and TiN particles.
The effect of water vapor on the mechanical properties of a porous nickel/yttria-stabilized zirconia (Ni–YSZ) composite (volume ratio of Ni:YSZ = 40:60) was evaluated at 850°C, a typical operating temperature of a reversible solid oxide cell. Both the flexural strength and static fatigue limit of Ni–YSZ obtained from the static fatigue lifetime under a wet atmosphere (containing 4% H2O) were lower than those under a dry atmosphere. This can be explained by absorption of H2O molecules into YSZ particles, resulting in accelerated crack growth. The fatigue limit of Ni–YSZ was confirmed to be extremely low, corresponding to almost one-third of the flexural strength.
The crossed-lamellar structure is known to exhibit a fantastic microarchitecture and excellent fracture resistance. Despite a similar morphology, this structure belongs to a family of homeomorphic microstructures with complex and varied crystallographies. In the present study, the crystallographies of different parts in Cymbiola nobilis shell were studied. The width of the first building blocks becomes increasingly thicker from the top to bottom of inner and middle layers. All the crystallites tend to align their c-axes towards the shell surface, and two twinned crystals share the c-axis at the top of inner and middle layers, while at the bottom the 001 pole figure shows two orientation components with c-axes inclined, and four preferential b-axis orientations distributed into two pairs. Texture analysis provides important information about the nature of shell growth, and suggests that the shape of the building blocks may be controlled by the crystallographic arrangement during the aragonite deposition.
We prepared SrCuO2 thin film by radio-frequency magnetron sputtering on glass substrate and have investigated its post-annealing effects on structure and thermal conductivity. The as-sputtered film belongs to two-dimensional spin system SrCuO2, namely, layer-type SrCuO2, which has a possibility of exhibiting high, anisotropic thermal conductivity by magnetic excitation of the spins. It was found that the as-sputtered film has (001)-orientation in which the spin layers are parallel to the surface of substrate and that post-annealing results in enhancement of crystallinity of the film such as disappearance of grain boundaries, which can cause an increase in thermal conductivity.
Hybrid materials were prepared from ground glass powder and various zeolites such as A-type, mordenite, X-type, and Y-type zeolites, and their ion removal effect was investigated. The hybrid materials of A-type, Y-type, and mordenite zeolites showed similar Sr2+ removal rates from aqueous solutions. The removal rate of Sr2+ ions increased as the amount of zeolite in the hybrid materials increased. Compared with other hybrid materials, the hybrid materials of X-type zeolite showed higher Sr2+ removal rates, especially for zeolite content greater than 25%. As the amount of X-type zeolite in the hybrid materials increased, the Sr2+ removal rate increased greatly, with a 100% removal rate when the content of X-type zeolite exceeded 62.5%.
Minor metals such as tungsten (W), molybdenum (Mo) and rhenium (Re) are necessary for high performance products, and a steady supply of them is very important. These metals are used for the X-ray target of the X-ray computed tomography equipment. In this study, we studied a dry separation method of W from discarded targets using the difference of volatilization behavior of the metal oxides. We obtained a 96% separation rate of W from the target by grinding, oxidation (1073 K, 5 h) and volatilization (1223 K, 5 h).
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Edited and published by : The Ceramic Society of Japan Produced and listed by : Komiyama Printing Co., Ltd.(Vol.115 No.1344-Vol.116 No.1351, Vol.118 No.1376-) Letterpress Co., Ltd.(Vol.116 No.1352-Vol.118 No.1375)