Search

This research involved comprehensive studies on thermal, physical, and morphological properties of SiO2-Na2O-CaO-P2O5 (SNCP) glass-ceramic at various sintering temperatures. The study in SNCP glass-ceramic using soda-lime-silica (SLS) wastes glass and clam shell (CS) wastes as the main raw of materials via conventional melt-quenching technique and solid state sintering are interesting and challenging by considering the research using waste materials to fabricate novel SNCP glass-ceramic. The main peaks, Na3PO4 and Ca3Na6Si6O18 were assigned to high crystallization temperature (Tc) at 650-950°C. The density of samples increases at 550-750°C and decreases at 850-950°C due to the increase of sample thickness and higher specific volume at high sintering temperature. FESEM micrograph showed that existed porous increased at sintering temperature 850-950°C contributes effect to low densification of the sample.

Nanocrystalline [Mn.sub.0.5][Zn.sub.0.5][Fe.sub.2][O.sub.4] ferrite was successfully synthesized by ball milling a powder mixture of MnO, ZnO, and [Fe.sub.2][O.sub.3] under argon and oxygen atmospheres. The effects of the milling time, milling atmosphere, and annealing temperature on the milled powders were examined. X-ray diffractometry (XRD), scanning electron microscopy, and transmission electron microscopy were used to evaluate the powder particle structure. The XRD results indicated that after 20 h of ball milling the MnO-ZnO-[Fe.sub.2][O.sub.3] powder reacted with a solid- state diffusion reaction route producing Mn-Zn ferrite nanoparticles in the milled samples with both atmospheres. However, some [Fe.sub.3][O.sub.4] phase alongside Mn-Zn ferrite, both being spinel-phase, was detected for 40 h milled powders in the argon atmosphere. Those milled powders in the argon atmosphere had smaller crystallite size than the other ones. In the final stage of milling (40 h), the average crystallite size and lattice strain were 20 nm and 0.51%, respectively, ans 25 nm and 0.48% for milled samples in the argon and oxygen atmospheres, respectively. Vibrating sample magnetometer results indicate that the saturation magnetization and coercivity were 34 emu/g and 30 Oe, 18 emu/g and 70 Oe, respectively, for the 40 h milled samples in argon and oxygen, which were annealed at 800°C for 2 h. PACS Nos.: 75.50.-y, 75.50.Pq, 75.50.Tt, 81.05.Gc, 81.40.Jj. Resume: Nous synthetisons Lα ferrite nanocristalline [Mn.sub.0.5][Zn.sub.0.5][Fe.sub.2][O.sub.4] en melangeant des poudres de MnO, ZnO et [Fe.sub.2][O.sub.3] dans un moulin a billes, sous des atmospheres d'argon et d'oxygene. Nous examinons les effets du temps de melange dans le moulin, de l'atmosphere et de Lα temperature de recuit sur les poudres. Nous utilisons Lα diffraction X (XRD), ainsi que Lα microscopie electronique a balayage et a transmission pour evaluer Lα structure de Lα poudre obtenue. Les resultats XRD indiquent qu'apres 20 hde moulinage a billes, les poudres MnO-ZnO-[Fe.sub.2][O.sub.3] reagissent via un mecanisme de diffusion a l'etat solide pour former des nanoparticules de ferrite Mn-Zn dans les deux atmospheres. Apres 40 h de moulin dans l'atmosphere d'argon, on observe Lα formation de Lα phase [Fe.sub.3][O.sub.4] en plus du Mn-Zn, les deux dans Lα phase spinelle. Ces poudres moulinees dans l'atmosphere d'argon ont des cristallites plus petites que l'autre. Dans Lα derniere partie du moulinage (40 h), Lα grosseur des cristallites et Lα deformation de reseau sont de 20 nm et 0,51%, 25 nm et 0,48% pour les atmospheres d'argon et d'oxygene respectivement. Les resultats VSM indiquent que Lα magnetisation de saturation et Lα coercitivite sont 34 emu/g et 30 Oe, 18 emu/g et 70 Oe, pour les echantillons moulines dans l'argon et l'oxygene respectivement et soumis a un recuit a 800°C pendant 2 h. [Traduit par Lα Redaction], 1. Introduction In recent years much attention has been paid to synthesis of spinel ferrite nanoparticles because of their technological and scientific significance as well as the presence of unexpected [...]

Problem statement: In the last decade, the studies and investigation on polymer-based composites have drawn significant attention owing to improvement in their mechanical, thermal, electrical, optical and pharmaceutical properties as compared with pure polymer. Approach: Different compositions of [Ni.sub.0.2][Zn.sub.0.8][Fe.sub.2][O.sub.4] (NZF) and Polypropylene (PP) can alter the useful properties of polymer-based composites. Hence, the determination toward significant percentage of NZF added into PP can improve the dielectric properties of the composites. NZF was prepared using conventional solid-state method and composites of isotactic PP filled with NZF were fabricated. The dielectric properties of the composite were investigated using Agilent 4284A Precision LCR meter. Results: The results indicated that with increasing ratio of wt% NZF, the dielectric constant and dielectric loss of the composite increases. The composition of 30 wt% NZF gave the highest value of the dielectric constant in the frequency range of 100 Hz-10 kHz at room temperature. Conclusion: The incorporation of ceramic filler improved the dielectric constant and increase the dielectric loss of the composite correspondingly increases its potential use as an absorbing material for electromagnetic waves. Key words: Dielectric properties, composites, filled polymer, nickel-zinc ferrite, polypropylene, INTRODUCTION Ferrites which have many applications at microwave frequencies are very good dielectric material. Ferrites have high electrical resistivity (Mohan et al., 1999), low dielectric loss and chemical stability. However, [...]

Abstract: This work reports on our earnest effort to development a Pulsed Laser Ablation Deposition system for the production of carbon nanotubes (CNTs). The correct condition such as the pressure, [...]

A comparative experimental study of the magnetic properties of CoPt3 and CoPt3/Au nanoparticles as well as a detailed study of the structural properties of the samples by X-ray diffraction, Transmission electron microscopy, and vibrating sample magnetometer is presented in this work. In addition, the effect of particle size on the structure and magnetic properties of nanoparticles prepared by microemulsion is studied. The correlation between particle size, crystallinity, and magnetization was studied as well. CoPt nanoparticles have been studied intensively over the last decade because of their increased magnetic anisotropy in the ordered phase that can be interesting for high density magnetic recording. A significant high coercivity for as-prepared CoPt3 and CoPt3-Au nanoparticles was obtained at room temperature and enhanced after annealing. The focused aim of our study is to obtain high coercivity at room temperature that follows the Curie-Weiss law. This indicates an interacting system in which the nanoparticles behave like single domain ferromagnetic materials in the particle size range of 8 to 35 nm. In addition, the interaction increases by cooling the samples to low temperature around 15K. Temperature dependence 1/M graph was obtained to investigate the behavior of nanoparticles at low temperature and shows the best fit with Curie-Weis mode. [ABSTRACT FROM AUTHOR]