2014

A method for the preparation of TiO2 thick films made of anatase nanocrystallites and featuring a mesoporous structure is described. Modification of a typical sol–gel synthesis that uses Titanium (IV) isopropoxide (TTIP) as precursor, through both the incorporation of a non-ionic surfactant (Tween 20) and the optimization of thermal treatments, allows to increase the thickness of each spin-coated layer, and to obtain by successive runs porous, transparent, homogeneous and crackless films with thickness up to 1.2 μm.

A sensor for measuring small convective heat flows (<0.2 W/cm^2) from micro-structured surfaces is designed and tested. This sensor {exploits the notion of thermal guard and is purposely designed} to deal with metal samples made by additive manufacturing, {such as} direct metal laser sintering (DMLS).

Composite and nanocomposite ceramics have achieved special interest in recent years when used for biomedical applications. They have demonstrated, in some cases, increased performance, reliability, and stability in vivo, with respect to pure monolithic ceramics. Current research aims at developing new compositions and architectures to further increase their properties. However, the ability to tailor the microstructure requires the careful control of all steps of manufacturing, from the synthesis of composite nanopowders, to their processing and sintering.

The fabrication of transparent polycrystalline Y3Al5O12 (YAG) is still a challenge, requiring the achievement of highly pure and fully dense, homogeneous materials. An important role is played by the powder characteristics: pure, fine and unagglomerated powders are essential for achieving full density and the required microstructural features. Keeping in mind these requirements, the aim of this work was to investigate the role of different synthesis parameters during co-precipitation, which is widely used to prepare YAG powders for transparent devices.

Ceramic nanocomposites, containing at least one phase in the nanometric dimension, have received special interest in recent years. They have, in fact, demonstrated increased performance, reliability and lifetime with respect to monolithic ceramics.

As the robotics is moving its interest from the machine tools for industrial production to biomimetic, even human-like systems, the need for materials that fulfill skin role arises. Skin presents a structure that has multiple roles such as protection and tact. The basic requirements for a skin mimetic material are flexibility and a measurable physical property triggered by the pressure. In this work hybrid piezoelectric materials are prepared and characterized. The flexibility of materials is assured by the polymeric matrices while ceramic oxide fillers grant a piezoelectric response.

The adhesive bonding technology can be used in combination with other traditional joining methods, such as mechanical fastening techniques (e.g. rivets or bolts) or welding techniques, generating a hybrid joint. Hybrid adhesive joints are designed to exploit the advantages of the different techniques and, if possible, overcome their drawbacks. This study focuses on the interference fitted/adhesive bonded joining technique. This method consists in two cylindrical components coupled together by inserting one into the other, after having placed an adhesive on the mating surfaces.

Thermoplastic poly(phenylene oxide) (PPO)-matrix composites were prepared and characterized in order to evaluate the effect of different ceramic fillers on the thermal and combustion behavior of the matrix. In particular, ceramic particles having three different shapes were exploited as fillers, particles showing a platelet-like, a needle-like or an equiaxial morphology. The composite materials were produced through a melt blending method, which yielded a homogeneous distribution of the ceramic particles in the organic matrix.