PREPARATION AND SPECTROSCOPIC PROPERTIES OF Ca2Al2SiO7: Tb3+ PHOSPHOR

<p>The Tb³⁺ rare earth ion doped Ca₂Al₂SiO₇material has tetragonal phase structure that has been successfully synthesized by solid state reaction method with optimal conditions: the sintering temperature at 1280^oC for duration of 60 minutes and the B₂O₃ flux agent content 4%wt. The Photoluminescence (PL) spectrum of Tb³⁺doped Ca₂Al₂SiO₇ phosphor consists of narrow lines with peaks at 545 nm, 440 nm, 462 nm, 494 nm, 590 nm and 622 nm that corresponding to 4f electronic transitions of Tb³⁺ ion. The peak at 545 nm has the highest luminescent intensity. The influence of synthesis technology and the luminescent characteristics of the phosphor are presented and discussed.</p>

Effect of Sb2O3 and/or CdO nanoparticle substitution on the properties of high-TC superconducting Bi1.6-x SbxPb0.4Sr2Ca2-yCdyCu3OZ material

High temperature superconductors materials with composition Bi1.6-xSbxPb0.4Sr2Ca2-yCdyCu3OZ (x = 0, 0.1, 0.2 and 0.3) and (y = 0.01 and 0.02), were prepared by using the chemical reaction in solid-state ways, and test influence of partial replacement of Bi and Ca with Sb and Cd respectively on the superconducting properties, all samples were sintered at the same temperature (850 oC) and for the same time (195 h). The structural analysis of the prepared samples was carried out using X-ray diffraction (XRD) measurements performed at room temperature, scanning electron microscope (SEM) and dc electrical resistivity was measured as a function of temperature. It was found that the sample prepared by partial substitution of Sb at ratio (x= 0.2) and Cd with ratio (y=0.01), has the maximum value of zero resistance temperature, where was the TC(onset) and TC(0) values for this sample are (140 K) and (123 K) respectively, and XRD results reveal that this sample has the highest percentage of Bi- 2223 phase, as well as the analysis of XRD patterns of the prepared materials showed polycrystalline structure and signalize that all samples had an orthorhombic crystalline structure. It was concluded that Sb2O3 nanoparticles it may be acts as a flux agent in the matrix to lower the partial melting temperature of the samples and that leads to the promotion of the high-TC phase.

Low Temperature Sintering of Lead-Free BaTiO3-Based X9R Ceramics with Bi2O3 Dopant and Assisted by LiF-CaF2 Flux Agent

The sintering temperature of BaTiO3powder was reduced to 950°C due to the Bi2O3-LiF-CaF2addition.Excellent densification was achieved after sintering at 950°C for 10h. The low sintering temperature of newly developed capacitor materials allows a co-firing with pure silver electrodes.The dielectric constant and the temperature stability of the dielectric constant satisfied the X9R standard, which dielectric properties of were ε25°C1115, ΔC/C25°C±12% (55~200°C), tanδ1.5% (25°C).

Effect of Additives on the Synthesis of Foam Glasses from Polishing Porcelain Tile Waste and Carbon Ash

Lightweight foam glasses have been prepared from a mixture of solid wastes, namely polishing porcelain tile waste and carbon ash. In this work, we illustrate the effects of additives, including the carbon ash, flux agent Na2B4O710H2O and foaming stabilizer Na3PO412H2O on the quality of the foams. The results indicated that the optimum carbon ash content is 2%, and the compressive strength would fall with the addition of Na2B4O710H2O and Na3PO412H2O.

High Thermal Conductive Inter Chip Fill for 3D-IC through Pre-applied Joining Process

Three dimensional (3D) IC has been proposed for high performance and low power in recent years. Due to the narrow gap between stacked chips and fine pitch of bumps, new inter chip fill (ICF) which can be used for pre-applied ICF process is required. The heat generation of 3D-IC is higher than 2D, so that a high thermal conductive inter chip fill (HT-ICF) is simultaneously required to dissipate the heat from 3D-IC and for the purpose of pre-applied ICF and HT-ICF, highly active flux agent and thermal conductive materials such as filler and matrix have been called for at the same time. In this study, some kind of materials were prepared, synthesized and optimized for the HT-ICF, and we evaluated its characteristic and confirmed applicability to pre-applied joining for 3D-IC.

Production of A356/TiB2 Nanocomposite Feedstock for Thixoforming by an Ultrasonic Method

Metal matrix nanocomposites (MMNCs) are promising materials to produce engineering components for the automotive and aerospace industry. This study aims to determine the feasibility of Al/TiB2 nanocomposite fabrication by the combination of the ultrasonic method and flux-assisted particle incorporation for the production of thixoforming feedstock material. Flux assistance has been invoked to attempt to overcome challenges with the presence of oxide on the surface of the foil in the aluminium foil capsulate method. A356 alloy has been reinforced with 0.25 wt.% TiB2 nanoparticles using different methods; 1. Flux-assisted casting, 2. Flux-assisted casting with ultrasonic cavitation, and 3. The Al foil capsulate method for particle feeding with ultrasonic cavitation. The composite fabricated by the ultrasonic method with the use of flux agent provided a non-dendritic microstructure which is the requirement for thixoforming. It was found that the flux-assisted casting method is not appropriate for achieving nanoparticle entry into the melt in MMNC fabrication due to the buoyancy forces of nanoparticles, unlike micron-sized particles.

Low-Temperature Sintering Lead-Free Barium Titanate-Based X7P Ceramics with Bi2O3 Dopant and ZnO–B2O3 Flux Agent

The sintering temperature of BaTiO3 powder was reduced to 870°C due to the H3BO3-ZnO-Bi2O3 addition.Excellent densification was achieved after sintering at 870°C for 15h. The low sintering temperature of newly developed capacitor materials allows a co-firing with pure silver electrodes.The dielectric constant and the temperature stability of the dielectric constant satisfied the X7P requirements, which dielectric properties of were ε25°C≥ 2800, εr/εr25°C≤±10% (–55~125°C), tanδ≤1.5% (25°C).

New Chromium-Calcium Titanate Red Ceramic Pigment

synthesis and characterization of a new chromium- calcium titanate red ceramic pigment is described in this communication. The pigment is based on the solid solution of chromium (IV) in calcium titanate and was characterized as red-brown pigment in a CaO-ZnO-SiO2 transparent glaze used for ceramic tiles (1080°C). XRD, UV-Vis-NIR spectroscopy and CIE-L*a*b* techniques of characterization have been employed. The L*a*b* valour of the optimal pigment with 0,015 mol/mol of chromium fired at 1100°C with a soaking time of 3 hours and 5% weight added to the transparent glaze is 59.3/12.5/9.5. Likewise 5%w. addition of NHCl used as flux agent increase b* and decrease L* valour (L*a*b*=45.2/15.3/5.3).

Low Sintering of the Temperature-Stable Dielectric Ceramics Based on Barium Titanate in Reducing Atmosphere

The optimized composition and sintering process of the low sintering X7R-type temperature-stable dielectric ceramics based on Barium Titanate in reducing atmosphere have been investigated. Flux aids SiO2-B2O3-Li2O were used in the experiments. The influence of composition and the content of flux agent on the microstructures and properties of ceramics materials were systemically studied. The X7R-type dielectric ceramics materials could be sintered at low temperature of 950oC in H2/N2 atmosphere, by optimizing flux content and adjusting process parameters. The dielectric constant of ceramics was effectively improved using two-step sintering process.