This paper proposed a kind of Aluminum (Al) foil filler with sputtering Ni/Al double layers on surface and a brazing method of elevating temperature. Results showed that this coated foil filler could make Al2O3 film on aluminum surface broken and sweep them into brazing seam because it was buried by Ni/Al double layer. The direct brazing of Al alloy to Al2O3 could be realized without interface reaction transition layer. Rising brazing temperature could enhance the interface between seam and ceramic, making joint fracture transfer from the interface into seam gradually. The shear strength of joint was improved to the maximum of 158 MPa at above 840 °C from 49 MPa at 680 °C.
The high energy density of hydrogen, in addition to its convenience for transportation and infinite resource base, make it a promising energy carrier. Solid oxide fuel cells (SOFCs), in particular—which utilize the oxidation of hydrogen at high temperatures to generate electricity—have been studied widely because of their high efficiency and relatively low cost. However, the lack of a suitable mass production method currently precludes the commercialization of SOFCs. To address this, we herein evaluate tape-casting as a means to reduce the cost of SOFC mass production. A simple de-airing technique is used to simplify the production process and an electrolyte-supported SOFC is produced without employing a buffer or functional layers. The rheological properties of green tape slurries are explored to improve tape completeness and electrolyte performance. Electrolyte conductivity is measured for a fabricated half-cell; the fine structural details are analyzed via scanning electron microscopy. As a result, a unit cell with an open-circuit voltage of 1.05 V and an electric power density of 0.476 W cm−2 at 800 °C was fabricated.
In the Li2O–Ta2O5–TiO2 system, Li1+x−yTa1−x−3yTix+4yO3 (0.14 ≤ x ≤ 0.175, 0.04 ≤ y ≤ 0.175) forms a superstructure by periodical insertion of an intergrowth layer in a matrix having a trigonal structure. In this study, to apply this unique structure as a host material of phosphor, new phosphors with a red emission color were synthesized by doping Mn4+ ion. The phosphor emitted at around 685 nm excited by 493 nm. The photoluminescence (PL) intensity closely related to the ratio of Mn4+/Mn3+ ion because the ratio changed by sintering temperature and/or Ti content in the matrix. The relationship between PL intensity and crystal structure was investigated using X-ray diffraction, a transmission electron microscope, and X-ray absorption fine structure.
In this paper, the synthesis of C12A7 nanopowders with OH− specie inside cage via biological method using Aloe Vera (A. vera) leaf extract with different concentrations of 0, 15, 20, 25 and 50%, and microwave-assisted synthesis was reported. The effects of A. vera leaf extract concentration on the structure, morphology and specific surface area of C12A7 nanopowders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy and N2 gas adsorption–desorption isotherm, respectively. The functional groups of C12A7 nanopowders with OH− specie inside cage were analyzed by fourier transform infrared spectroscopy (FT-IR). The XRD patterns showed that the pure peak of C12A7 was obtained from the samples prepared with A. vera leaf extract concentration of 20% and above. The minimum crystallite size of the C12A7 nanopowders was found to be 43.17 nm for the sample prepared with 25% A. vera leaf extract concentration. The maximum specific surface area (SBET) obtained from N2 gas adsorption–desorption isotherm was found to be 17.25 m2/g with a minimum pore size of 12.24 nm for the sample prepared with 25% A. vera leaf extract concentration. The FT-IR spectra of C12A7 prepared with A. vera leaf extract reveals the presence of amide of protein in A. vera leaf bonded to C12A7 indicating the biological responsibility for the synthesis of C12A7. Furthermore, in this work with the microwave-assisted synthesis of C12A7 nanopowders, the calcining time could be reduced by 10 h compared with a chemical process and temperature could be reduced to 900 °C compared with a standard sintering temperature.