2013

A modified gel-casting process was developed to produce both dense and highly porous (40% volume) yttria tetragonal zirconia polycrystal (Y-TZP) using agar, a natural polysaccharide, as gelling agent. A fugitive phase, made of commercial polyethylene spheres, was added to the ceramic suspension before gelling to produce cellular ceramic structures. The characterization of the microstructural features of both dense and cellular ceramics was carried out by FEG SEM analysis of cross-sections produced by focused ion beam.

Various compositions of barium-doped hematite between pure hematite (α-Fe2O3) and pure barium hexaferrite (BaFe12O19) were synthesized by solid state reaction. The XRD analyses confirmed the progressive evolution of the two crystalline phases. Tests as humidity sensors show that the electrical resistance of samples containing high proportions of hexaferrite phase is strongly influenced. Electrochemical impedance spectroscopy (EIS) analyses under air or argon revealed an intrinsic semiconducting behavior for hematite and samples doped with 3 and 4 wt % equivalent BaO.

This paper reports on a study of two organic-inorganic hybrid materials used as consolidants. Both formulations were synthesized from an inorganic precursor (Tetraethoxysilane, TEOS) added in different percentages (up to 60% per hundred resin) to a polysiloxane epoxy formulation (TEGO RC 1411) and to a cycloaliphatic epoxy resin (3,4 Epoxyciclohexylmethyl -3,4-epoxyciclohexane carboxylate), and cured in the presence of ytterbium as acid catalyst. The film properties and the formation of silica clusters were investigated.

In this paper characteristics of an AlMg/AlN composite produced "in-situ" and processed in a flowing N2 atmosphere is investigated. Some critical parameters such as the manufacturing process temperature, the percentage of the magnesium consumed, the flowing reactive gas flow and the time for completing the manufacturing are considered as variables for the parametric investigation. Moreover, the effect of different amount of Mg employed has been also investigated, since Mg acts as a catalyst at the surface both for the gas/liquid and solid/liquid systems.

Purpose: The main goal of this study is to develop and obtain some competitive products, with high added value. In particular, the attention will be focused on the possibility to obtain a new class of Cobalt based alloy by Ti addition. Design/methodology/approach: Modification of the composition by Ti addition can increase the corrosion resistance, processing and at the same time can improve the alloy biocompatibility. Findings: Addition of these elements has a positive effect on the alloy hardness.

Ceramic matrix composites (CMCs) can be attractive for structural applications, but their machining by conventional methods is expensive and often critical. Complex geometries on advanced ceramics require contactless processes, such as electrodischarge machining or drilling (EDD). These proved to be viable for CMCs with electrical resistivity below a critical value in the range of 1-3 Ω m. The condition is complied with by many CMCs: an example is alumina with titanium carbide.

TiO2 nanotube (NT) arrays with different lengths were fabricated by anodic oxidation of Ti foil and free-standing NT membranes were detached by the metal substrate and bonded on the fluorine-doped tin oxide surface implementing an easy procedure. Morphology of the as-grown material and of the prepared photoanode was investigated by means of electron microscopy, deepening the investigation on the thermal treatment effect.