Rosa Di Maggio

Hydrophobic siloxane paper coatings: the effect of increasing methyl substitution

Paper is an organic material widely used in cultural heritage and mainly composed of cellulose mixed with lignin, hemicellulose and small amounts of additives. This paper deals with siloxane coatings on pure cellulose paper, applied by sol–gel dipping in sols prepared with different siloxane precursors (tetraethoxysilane, methyl triethoxysilane, dimethyl diethoxysilane, trimethyl monoethoxysilane). The coated samples were characterized using various techniques (Fourier Transform Infrared Spectroscopy FT-IR, Nuclear Magnetic Resonance NMR and Scanning Electron Microscopy and Energy Dispersive Spectroscopy SEM–EDS), measuring their mechanical properties, flame resistance and contact angles, and a colorimetric test. The coated samples’ behavior was more hydrophobic the higher the methyl number of siloxane precursor, regardless of the coating’s thickness. Increasing the thickness improved the mechanical and thermal properties. The thickest coatings were obtained using a double coating process and a basic catalyst for the hydrolysis step, but this latter condition facilitated the formation of surface agglomerates, which make the paper too stiff and yellow.

Characterization of Ceria Stabilized Zirconia Coatings on Metal Substrates

In this study ceria stabilized zirconia was used to obtain an uniform and adherent film on iron and 304 S.S.. Coatings were prepared by dipping in solutions of organometallic precursors of zirconium and cerium. Structure and morphology of samples were investigated using SEM and XRD techniques before and after thermal treatments. The oxidation behaviour in air of coated samples was followed through thermogravimetrical analysis in a range of temperature from 773 K to 1123 K. The preliminary results show, for the samples coated and pretreated in high vacuum at 923 K, a good decrease in oxidation rate.

Chloride-based route for monodisperse Cu2ZnSnS4 nanoparticles preparation

A new approach based on hot injection method is proposed to gram-scale Cu2ZnSnS4 nanoparticles production minimizing the use of organic solvents. Nanocrystal synthesis was performed starting from metal chlorides and pure sulphur powder and using Oleylamine as capping agent. As a result, core-shell nanoparticles with a narrow size distribution were obtained.

Conceptual Study of a Thermal Storage Module for Solar Power Plants with Parabolic Trough Concentrators

Technologies and methods for thermal energy storage have been well tested in CSP Con‐ centrated Solar Power – plants [1, 2]. Solar tower plants (e.g. Solar Two, USA) and advanced parabolic trough plants (e.g. Archimede by ENEA, Italy) use molten salts both as heat trans‐ fer and thermal storage fluid. Differently, traditional trough plants (e.g. Andasol, Spain) dis‐ tinguish the fluid through the solar field (synthetic oil) from the one used in the storage system (molten salt). Hence, storage applications have only been proven in liquid state and in large scale plants.

Pressureless forming of NiAl and Ni3Al powders: A preliminary investigation

Extremely limited ductility makes several of the processing and manufacturing steps of intermetallic-based materials very critical. The handling of intermetallic cast ingots and the machining of intermetallic components have often proved to be operations with a particularly high failure rate. On the other hand, the processing problems of intermetallic alloys resemble those that are commonly faced with ceramic materials. Therefore, processing routes similar to those used for brittle ceramics have been considered for the manufacturing of intermetallics. In this respect, powder metallurgical methods are certainly very attractive and can potentially help to overcome some of the mentioned drawbacks. In this study, the results of a novel approach to the pressureless forming and sintering of Ni-aluminide powders are presented. This research is an extension of a similar investigation on ceramic (ZrO2 and Al2O3) and metallic (AISI316 inox steel) powders. In all cases, the powders are mixed with a hybrid inorganic-organic binder. The binder-powder mixture can be given the final shape before full polymerization of the binder, which occurs in several minutes at room temperature. Subsequently, debinding and sintering heat treatments are carried out under controlled atmospheres, the composition of which is deliberately changed during the treatments in order to enhance the different processes that are expected to occur. The thermal treatment conditions have been selected and optimized on the basis of thermoanalytical results. The microstructural characterization of the intermediate and final products have been carried out by scanning electron microscopy (SEM) and energy dispersive microanalysis (EDM).