Abstract: Boron nitride (B1.0N0.9) nanoparticles have been prepared by the spray-pyrolysis of
borazine. Characterization of the B1.0N0.9 nanoparticles by SEM, and HRTEM demonstrated that
samples form elementary blocks containing slightly agglomerated nanocrystalline particles with
sizes ranging from 55 to 120 nm. Their thermal behavior has been investigated and
thermogravimetric analyses of B1.0N0.9 nanoparticles showed that they are relatively stable in air
Abstract: We introduce a case study of “high sphericity” and “high uniformity” generated through flame synthesis. Recently, cosmetics need to solve 1) UV-protective effect, 2) transparence, and 3) smooth-textured touch. However, the best recipe and usable evaluation methods are not established. This research is a result combined with a theoretical approach of flame formation process, and a strategic regional alliance of the “AIST” grant venture. A new manufacturing and evaluation method has been commercialized in the forms of a highly original cosmetics and a new evaluation device.
Abstract: In the frame of a wide research program devoted to the matter recovery from waste by
means of thermal processes, particular efforts have been put into the study of biomasses and waste
residue of peculiar composition, which could be used as precursors of ceramic materials.
Rice shells are waste biomasses coming from the purification process of rice, which show a high
carbon and silica content. The exploitation of these peculiarity promoted a series of experimental
activities, aimed at the production of ceramic materials through high temperature carbothermal
synthesis reactions. The synthesis products were characterized by X Ray Diffraction (XRD) and
scanning electron microscopy (SEM) and the data confirmed the production of ceramic silicon
nitride (Si3N4) at high yield and purity, under the adopted process parameters.
Abstract: Development of an efficient technology to produce nanopowders for nanostructured materials with improved mechanical, novel electromagnetic and optical properties is still of current importance. Nanoparticles can be made by means of laser-assisted material evaporation and subsequent vapor condensation. The method provides high-purity weakly agglomerated nanopowders with narrow grain size distribution, and can be applied to various materials. However, up to these days this technique has not found wide recognition because of a low output rate and high energy consumption. This report deals with the production technology and characteristics of nanopowders produced with the help of Yb-doped fiber laser. Data for the nanopowders characteristics, as well as output rate and energy consumption are discussed in this paper. The evaporation of materials with the help of the fiber laser was proved to be an efficient method for commercial production of the fine nanopowders.
Abstract: In the last years several projects have been developed for treatment of fly ash with the aim of their reuse. A final target of these researches is to evaluate the real performance of the new materials obtained by the treatment and the actual and, if the case, potential markets for the foreseen products. Indeed, the use of a recycled inert would reduce the consumption of natural resources and this is one of the main environmental EU target. Examples are clinkering, road asphaltation and some construction work where specific performances are requested. Moreover, the reuse of inerted fly ash will obtain a reduction of carbon dioxide produced by the necessary treatments of primary materials, as limestone in concrete production.
At the University of Brescia (Italy) a new process, based on colloidal silica medium, has been developed to inertise fly ashes, containing heavy metals. This approach appears to be quite promising for industrial application in view of the easiness that can be foreseen in applying it to existing plants treating industrial fly ash. The obtained inert product is a powder, that can be employed as a filler in several application.
In this work we present first results about characterization of this new powder material, that can be applied as a filler.
Abstract: Wet-chemical syntheses have been applied to the production of ceramic powders, with the aim of tailoring compositional and micro/nanostructural features, as an imperative requirement toward the elaboration of ceramic components with improved functional or even structural properties. Three syntheses are here presented and discussed, respectively concerning a purephased, nanostructured YAG powder, a biphasic Al2O3-YAG composite and three-phased Al2O3- YAG-ZrO2 material. In particular, this paper is aimed to illustrate the path followed from the set-up of the easier synthesis of the mono-phased system to the definition of the advanced procedures for the production of more and more complex compositions.
Abstract: Preparation technique of the particulate composite materials in the alumina/YAG system
were studied. Within alumina particle suspension yttria precursor was precipitated with ammonium
carbonate. Drying and calcinationa at 600oC resulted in the mixture of alumina and yttria particles.
The latter being much finer than alumina particles. This mixture was additionally homogenized by
short attrition milling in an aqueous suspension of pH which level was selected on the basis of zeta
() potential measurements. It was found that acidic conditions (realized with HNO3) result in hard
agglomerates. Such powders showed poor sintering ability and not homogenous second phase
particles distribution. Much better properties were observed in case of powders homogenized under
basic condition. They give dense materials composed of YAG inclusions of sizes several times
smaller than shown by alumina grains and evenly distributed within the matrix. YAG particles
result from the reaction of Y2O3 with Al2O3 during heat treatment. Some compositions show
fracture toughness essentially higher than observed in pure alumina polycrystals.
Abstract: Highly crystalline cubic indium tin oxide (ITO) nanoparticles with narrow size distribution were successfully prepared directly in one step from the mixed solution of indium and tin salts by the solvothermal method with lean ethylene glycol as a solvent. The addition of water must inhibit the formation of ITO crystals, but can strongly promote the formation of In(OH)3 and InOOH, including tin hydroxide. Since In(OH)3 and InOOH was not found in water-free EG system, the transformation of In(OH)3 and InOOH into In2O3 phase must be remarkably slow so that once formed indium hydroxides become final product in water-containing system. The as-prepared particles in BuOH as a solvent consist of irregular shaped nanoparticles of ITO and InOOH. In the solvothermal system with glycol as solvents, direct formation of ITO solid particles was observed starting from amorphous indium hydroxides, In(OH)3 and InOOH phases are not detected as intermediates. In addition, their size with the range from 15 to 40 nm was easily operated with changing conditions, such as aging period and sodium hydroxide concentration. X-ray diffraction measurement and high resolution transmission electron microscopic observation revealed that basically single-crystalline ITO nanoparticles were successfully obtained, and doped tin atoms were uniformly distributed in the nanoparticles.
Abstract: Materials with A2B2O7 (pyrochlore) structure have received a significant attention for their applications as new protonic conductors and materials used in electronic devices. One of the unique synthesis routes for La2Zr2O7 (pyrochlore) powders is the glycine-nitrate combustion method, which shows superior properties of the synthesized powder by using glycine as a complexing agent. The Sr doped La2Zr2O7 powders in pure pyrochlore structure were produced using this approach. Selected characteristics of the synthesized powders, such as crystal structure, lattice parameters, crystallite size, the vibrational properties, the morphology of the particles, along with the specific surface area and particle size have been investigated. The dependence of some properties on annealing temperatures of the powders has been studied.