The effect of heat input rate, hatch spacing, and focus offset upon microstructure, hardness, and roughness of EBM-manufactured Ti – 6Al-4V titanium alloy was studied via a factorial experiment. It had been found that a coarser microstructure is generated for high heat input and low line offset. Increasing the heat input or conversely decreasing the line offset leads to a higher lath thickness with consequent lower hardness. The roughness of the top surfaces decreases with the increase of the heat input and the focus offset or with the decrease of the line offset. On the other side, the roughness of the side surfaces is dependent only on the heat input and it is proportional to the latter.

TiO₂ in the form of nanocrystals possesses photocatalyst properties leading to excellent capability of degrading a number of environmental contaminants such as organics, bacteria, and viruses.

Additive Manufacturing (AM) can be considered today as a real production technology, which allows to realize parts with a complexity degree that, in some cases, is not achievable otherwise. However, one of the most relevant weak spots is the high surface roughness, especially for metal parts, making necessary the adoption of post-process finishing treatments. This paper deals with the preliminary investigations on the Fluidised Bed Machining (FBM) technology, in which a sample is dipped into a fluidized bed, i.e. a two-phase system where an abrasive, kept in motion through a gas, behaves like a fluid performing a huge number of impacts on the considered surface. This peculiarity could guarantee a high degree of homogeneity of the treated surface morphology. The influence of the impact angle has been investigated by conducting experiments with AlSi10Mg plates made by Selective Laser Melting Technology (SLM), and the fluidized bed operated in bubbling fluidization regime. The treatment has been carried out by dipping the samples for a total time of 3 hours and monitoring the results with a step of 30 min for the first 2 hours. The treated surfaces have been characterized by means of Confocal Microscopy and Scanning Electron Microscopy (SEM). Weight loss measurements have been carried out as well for a preliminary evaluation of wear. Results suggest a poor decrease in surface roughness (S_a), as also demonstrated by the poor weight loss, both due to a low impact energy of the abrasives. However, variations of other surface texture parameters (S_z, S_sk, S_ku, R_dq), as well as SEM images, suggest that the main surface-abrasive flow interaction phenomena are micro-ploughing and micro-peening.

Magnetic chitosan nanoparticles, synthesized by in situ precipitation, have been used as adsorbents to remove sulfamethoxazole (SMX), a sulfonamide antibiotic dangerous due to its capacity to enter ecosystems. The adsorption of SMX has been carried out in the presence of tertiary wastewaters from a depuration plant to obtain more realistic results. The effect of pH on the adsorption capacity significantly changed when carrying out the experiments in the presence of wastewater. This change has been explained while taking into account the charge properties of both the antibiotic and the magnetic chitosan. The composition of wastewaters has been characterized and discussed as regards its effect on the adsorption capacity of the magnetic chitosan. The models of Elovich and Freundlich have been selected to describe the adsorption kinetics and the adsorption isotherms, respectively. The analysis of these models has suggested that the adsorption mechanism is based on strong chemical interactions between the SMX and the magnetic chitosan, leading to the formation of an SMX multilayer.

The additive manufacturing technologies are finding an increasing use due to their peculiarities. A limit that still hampers their massive application is the maximum dimension of the components than can be produced. This paper deals with the study of the joining process of additive manufactured parts. In particular, two different cases have been studied: i) Ti6Al4V parts made through electron beam melting joined through linear friction welding; ii) AlSi10Mg parts made through direct metal laser sintering joined through friction stir welding. The results obtained showed the feasibility of both the processes.