Search results for "Ball Milling"
showing 10 items of 16 documents
Experimental investigation and multi-scale modelling of the behavior of mechanically activated metallic powders : from binary systems to High Entropy…
2021
Generally, metal alloys consist of a main element associated with other elements present in smaller quantities such as iron, nickel, aluminum or copper alloys. The precise composition of an alloy is adjusted according to the required performance: high temperature behavior, corrosion resistance, mechanical properties, durability ... In 2004, a Taiwanese scientist, JW Yeh, had the idea of making an alloy base of several elements, at least 5, whose composition in the alloy varies between 5% and 30% at. Yeh invented the high entropy alloy (HEA). Mixed on a microscopic scale, the metals form a remarkably stable solid solution. The explanation is thermodynamic. An alloy is all the more stable as …
Microstructure-process relationship and reactivity at the nanoscale : a molecular dynamics study of Ni, Ni-Al, and Ti-Al metallic systems
2023
The process-microstructure relationship is central in materials science because the microstructure will determine the properties of the materials developed by the processes. In our work, we focused on different metallurgical processes by adopting a description at the atomic scale. This approach allows us to detect the elementary mechanisms that are at the origin of the observed microstructures without having to postulate macroscopic mechanisms or estimate the associated parameters. In this respect, molecular dynamics simulations provide a tool for "in-situ" observation of metallic systems as long as an atomic interaction potential is available. The originality of our approach consists in mo…
Luminescence properties of neodymium-doped yttrium aluminium garnet obtained by the co-precipitation method combined with the mechanical process.
2005
Nanopowders of yttrium aluminium garnet Y3Al5O12 (YAG) doped with neodymium ions were obtained by the co-precipitation method from the reaction of aluminium and yttrium nitrate and neodymium oxide with ammonia. After washing and drying the hydroxide precursors were calcined at 500, 700, 800 and 900 °C for 1 hour and at 1000 °C for 3 hours. This product was treated by ball milling in a zirconia vial for 0.5, 1.5 and 10 h in order to achieve smaller nanoparticles. The structure, microstructure, morphology and optical properties were investigated by means of diffractometric, microscopic and spectroscopic techniques. The course of the amorphous-to-crystalline transformation was complete after c…
Synthesis and characterization of nanocrystalline LaNi5 hydrogen storage materials
2009
With the growing environmental concerns of greenhouse gas emissions from the burning of fossil fuels, it is becoming increasingly important to switch to cleaner alternative fuels such as hydrogen [1]. Inter-metallic LaNi5 is one of the most widely used and studied solid-state hydrogen storage material – a pet material for the prototype systems using hydrogen fuel. However, nanostructuring effects on this systems are not yet fully explored. Recently we have carried out systematic studies regarding the effect of nanostructuring on the hydrogen sorption properties of this material [2]. Unlike some other potential hydrogen storage materials, which shows faster kinetics upon nanostructuring, the…
Desarrollo y caracterización de nuevos nanobiocomposites con propiedades mejoradas mediante varios métodos de procesado de interés en envasado de ali…
2015
El presente trabajo tiene como objetivo mejorar las propiedades de matrices biopoliméricas para su uso en aplicaciones de envasado de alimentos mediante el desarrollo de nanobiocompuestos utilizando diferentes metodologías de procesado o estrategias de incorporación de materiales nanoestructurados en el interior de las matrices biopoliméricas. Dos estrategias de incorporación fueron empleadas. La primera de ellas estaba basada en una pre-incorporación de los aditivos nanoestructurados, también llamados nanoaditivos, en oligómeros de ácido láctico mediante tecnologías de polimerización in situ (específicamente policondensación), dando lugar a masterbatches que, posteriormente, se mezclaban c…
Nanostructuring - a possible way to enhance the hydrogen sorption properties of materials
2009
A facile way to synthesize noble metal free TiO2 based catalysts for glycerol photoreforming
2023
In this work anaerobic heterogeneous photocatalytic solar/UV light reforming of glycerol in aqueous media was performed with Pt-photodeposition and noble metal free modified TiO2 photocatalysts prepared through ball milling, a very simple and cheap coupled catalyst preparation method. Different amounts of Cu2O or 3% CuO were loaded on TiO2 using ball milling and during each run glycerol conversion, hydrogen and CO2 formed in the gas phase and 1,3-dihydroxyacetone (DHA) and glyceraldehyde (GA) in the liquid phase were determined. The results were compared with the aim to verify the effectiveness of Cu2O in replacing Pt. Using noble metal free photocatalysts, 33% glycerol conversion, 10.3% an…