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In this paper, two tin-based alloys (Sn-2.5Ag-0.5Cu and Sn-48Bi-2Zn) are proposed as new lead-free solders. Alloys have been developed by melting pure elements. Samples have been evaluated in terms of microstructure, corrosion resistance and mechanical features. Corrosion tests have been performed in 3% NaCl solution by polarization curves and electrochemical impedance spectroscopy (EIS). SEM observations and EDS analysis were carried out on samples before and after corrosion tests. Static monotonic tensile tests have been performed on three specimens for each alloy. SEM and EDS analysis revealed the presence of Sn-Ag and Sn-Cu intermetallic compounds within the Sn-Ag-Cu alloy. As a result of corrosion test, the Sn-Ag-Cu alloy showed a better corrosion resistance with respect to Sn-Bi-Zn. Both alloys evidenced good mechanical properties higher than the traditional Sn-Pb system. Sn-Ag-Cu seems to be a suitable soldering material

Carbon nanotubes (CNTs) were chosen due to their excellent electrical properties. As delivered, CNTs are highly agglomerated, and to exploit their high aspect ratio is then necessary to disagglomerate them as much as possible. A diblock copolymer surfactant was used to aid CNT disagglomeration. Disagglomeration in solvent was assessed by TEM, whereas composite microstructure was observed by scanning electron microscopy. X-band waveguide measurements were carried out to assess complex permittivity and absorbing performance. On a same weight percent of filler basis, samples produced with the aid of surfactant show higher real permittivity than samples produced without. An equivalent circuit analogy is suggested to explain the results and relates composite microstructure with macroscopic permittivit