Influence of Cu2O Addition on Crystallization Process and Microstructure of Transparent Mica Glass-Ceramics

ArticleKey Engineering Materials. 617: 209-212 (2014)journal articl

Fabrication and Fracture Toughness of CNTs/Alumina Composites with Fine Microstructures

ArticleKey Engineering Materials. 617: 205-208 (2014)journal articl

Preparation and luminescent properties of Eu-doped transparent mica glass-ceramics

Eu-doped transparent mica glass–ceramics were prepared, the influence of Eu-doping on the crystallization of the parent glasses was investigated and the luminescent properties of the parent glasses and the glass–ceramics were estimated. A small additive amount of Eu element was very effective in preparing transparent mica glass–ceramics. However, the excess addition led to the coarsening of phase separation in the glass phase and the separation of unidentified crystal phases and β-eucryptite during heating of the parent glasses, which caused white opaque at lower heating temperatures. When mica crystals were separated, Eu ions entered the interlayers of mica crystals. The observed emission and excitation spectra showed that parts of Eu³⁺ ions which were added as Eu₂O₃ were reduced to Eu²⁺ ions during melting of the starting materials and heating the parent glasses in air and the energy transfer from Eu²⁺ to Eu³⁺ ions occurred.ArticleCeramics International. 36(4):1303-1309 (2010)journal articl

Deposition of boehmite on carbon nanofibers using aluminum alkoxide and its thermal transformation

We attempted to prepare carbon nanofibers (CNFs) bonded chemically with alumina particles using acid-treated CNFs and aluminum secbutoxide. The structure and morphology of the boehmite deposited on the CNFs, the boundary between the CNFs and the deposited boehmite, and the thermal transformation of the deposited boehmite were investigated using Raman spectroscopy, X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The boehmite deposited not only particulately on the CNFs but also in a film-like manner on parts of the CNFs. In addition, the boehmite could deposit not only on the disordered inner walls of the CNFs but also on the ordered inner walls. By heating at 1200 degrees C, the boehmite on the CNFs was transformed into alpha-alumina and theta-alumina. At this time, some alumina particles, particularly those formed on the ordered inner walls of CNFs, fell out of the CNFs, and only those alumina particles which might chemically bond with CNFs remained on the CNFs. Finally, CNFs dotted with alumina particles with a size of <50 nm were obtained. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.ArticleCERAMICS INTERNATIONAL. 41(10):13171-13178 (2015)journal articl

Analytical Approach for Oscillation Properties of Soft Materials

Abstract. It is well known that the Brusselator model reveals simple oscillations and damped oscillations by the suitable parameters. However there is no chemical reactor system that corresponds to the Brusselator model. We have a good real physical system that corresponds to the Brusselator model under some conditions. The system is a free damped oscillation of soft material and described by an equation of motion. In this paper, we show the relation between the Brusselator model and the physical system. We also estimate the experimental data of the physical system

Microstructures and luminescent properties of Ce-doped transparent mica glass-ceramics

Transparent mica glass-ceramics were prepared by heating parent glasses that had been doped with 0.5-15 mol% CeO2. During the melting and heat treatment, Ce4+ ions in the specimens were reduced to Ce3+ ions, and one or both of these ion species were then replaced with Li+ ions in the interlayers of the separated mica crystals. However, scanning transmission electron microscope (STEM) and Z-contrast imaging revealed that the mica crystals did not contain the same amount of Ce. On excitation at 254 nm, the parent glasses and glass-ceramics emitted blue light, which originated from the 5d to 4f transition of the Ce3+ ions. The emission of the glass-ceramic containing a smaller amount of Ce was attributed to the Ce3+ ions in both the glass phase and the mica crystals, whereas that of the glass-ceramics containing a larger amount of Ce was caused mainly by Ce3+ ions in the mica crystals. The dependence of the emission band of the parent glasses on the amount of Ce was a unique feature of the Ce-doped transparent mica glass-ceramics and was not observed in previous studies of Eu-doped parent glasses and mica glass-ceramics.ArticleMATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS. 177(7):504-509 (2012)journal articl