85 research outputs found
Caratterizzazione della resistenza a corrosione di leghe ferrose in liquidi ionici a base imidazolo,
The possibility to use ionic liquids (ILs) in several industrial applications, from galvanic to electronics, to CO2
capture in combustion processes, requires a deeper understanding of the compatibility of the ILs of major
interest with metallic materials that currently compose industrial plants. This work proposes the evaluation of
the corrosion behavior of a carbon steel (API 5L X52) and a stainless steel (AISI 316) in presence of methyl
imidazolium based ILs. The analysis focuses on the dependence of ILs corrosiveness on their chemical
formulation, with particular reference to the anion composition and to the chain length of the imidazolium cation
Utilizzo di nitrati come inibitori di corrosione per le armature nel calcestruzzo
Corrosion inhibitors have been long considered as an effective preventative technique to slow down the onset
and/or propagation of corrosion phenomena in reinforced concrete. Several substances have been evaluated
as possible candidates, and great interest has been dedicated to nitrite ion. When investigating how these
substances slow down corrosion related processes – chlorides diffusion, critical chloride threshold, CO2
penetration and corrosion propagation –interactions between inhibitor and concrete are also vital.
Recently, nitrate based compounds have been proposed as corrosion inhibitors, as they present lower cost
than nitrites and are already used in concrete as set accelerators. Some studies have shown that nitrates
inhibiting mechanism is similar to that of nitrites. This work proposes the evaluation of a nitrate based
substance as possible corrosion inhibitor in concrete, and compares its performance with a nitrite based
inhibitor
Tuning of anodic oxidation parameters for the production of nanostructured TiO2 films
Titanium dioxide is the most common among titanium oxides and minerals. It can be either synthesized bychemical routes or generated by anodic oxidation of titanium. The latter way allows to tune oxide properties bymodulating process parameters, and it has gained much attention thanks to the wide variety of thicknesses,morphologies, structures and compositions of the oxide produced. The peculiar engineered properties ofanodized titanium find applications in biomedical industry, automotive field, architecture and design, as well asin photovoltaic cells and in photocatalytic purification devices.This article provides an overview of anodic oxidation treatments currently applied to form nanostructured oxidelayers on titanium, paying special attention to their applications
Perfluoropolyethers as superhydrophobizing agents for carbon-based surfaces of fuel cell gas diffusion layers
Perfluoropolyether (PFPE) peroxide confers superhydrophobic properties to carbon black (CB) and carbon cloth (CC) as Gas Diffusion Layer (GDL) materials by direct functionalization. The thermal decomposition of PFPE peroxide synthesizes PFPE radicals which covalently bond the unsaturated moieties on carbonaceous surfaces. PFPE-functionalized CB and CC were characterized by X-ray photoelectron spectroscopy (XPS), surface area analysis, resistivity measurements, scanning electron microscopy (SEM) and contact angle measurements. The PFPE-modified materials resulted superhydrophobic were employed for the fabrication of single and dual layer GDLs. GDLs were tested in a single fuel cell at the lab scale. The cell tests were run at two temperatures (60°C and 80°C) with a relative humidity (RH) of hydrogen and air feeding gases equal to 80/100% and 60/100%, respectively
Immobilization of TiO2 nanopowders in multilayer fluorinated coatings for highly efficient clear and turbid wastewater remediation
The use of nanosized photocatalytic TiO2 in suspension or slurry type reactors is well reported. However, the industrial feasibility of such systems is limited, on account of the low quantum efficiency reported for slurry processes and of the need for a post-treatment catalyst recovery stage, which may present poor efficiency, with the double drawback of dispersing nanoparticles in the environment and losing precious photocatalyst. In this work, the photodegradative activity of titanium dioxide immobilized into a multilayered transparent fluoropolymeric matrix has been studied. Several TiO2 nanostructured powders featuring different primary particle size, crystalline phase and specific surface area have been produced by the flame spray pyrolysis (FSP) of organic solutions containing titanium (IV) isopropoxide. The activity of such powders has been tested and compared to that of TiO2 P25 by Evonik Degussa, which is the reference nanopowder commonly employed in the evaluation of the photocatalytic activity of non-commercial TiO2. A multilayer ionomeric-perfiuorinated matrix has been used to immobilize the powders, having high chemical resistance and transparency towards UV light, good permeability to oxygen and good wettability to favor interactions with the polluted aqueous solutions
Avaliação da eficiência de sistemas de proteção de superfície para concreto: absorção de água, migração de cloretos e ângulo de contato
Profile of patients with rheumatic diseases undergoing treatment with anti-TNF agents in the Brazilian Public Health System (SUS), Belo Horizonte - MG
- …