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Alloy design method which consists of theoretical analysis and experimental examination has been /is applied to develop three class of alloy systems, i.e. new Pb-free solders, alloy catalysts and biomedical alloys by using nanoparticles (NPs).

The aim is to increase the basic understanding of the properties and phenomena at the nano-scale length for tailoring materials by controlling composition and structure, in order to optimize their final properties. In the framework of Actions COST 531 and COST MPO602 some binary and ternary alloys of the Ag-Cu-Sn (SAC) nanosized reference systems and Sn-based alloys with metal nanoparticle (such as Bi, Sb, Co, Ni, Zn, Ge, Ag, Au) additions have been/are studied as Pb-free candidate materials. The alloy catalysts (Ag-Pd, Mg-Pd, Cu-Pd, Cu-Pt, Ni-Pt,..) and biomedical alloys (Ag-Au, Ag-Cu, Co-Cr, Ni-Ti, Ti-Al-V). have been/are investigated last few years (Action COST MPO903). The models and methods relevant for optimization and design of the aforementioned alloy systems have been developed in the framework of thermodynamics, kinetics and statistical mechanics can be summarized as: CALPHAD method for calculations of bulk and nano-sized phase diagrams, thermodynamic models for prediction of the surface (surface energy, segregation, gas adsorption), transport (diffusivity, viscosity, compressibility, el. resistivity) and structural (the concentration-concentration fluctuations in the long wavelength limit and the Waren-Cowley short-range order parameter) properties of the liquid or/and solid phases as well as the melting temperature depression and shift of invariant reactions in small systems with a decrease in particle size and coalescence (surface diffusion and/or Ostwald ripening).

  • TEM images of Bi–Sn CR_H two-phase sample: (a) bright field of single NPs, (b) dark field of single NPs, (c) bright field of agglomerated NPs, (d) dark field of agglomerated NPs.
  • Caloric curves of Co (blue) and Ih (red) at 309 atoms, for a CuPt 1 : 1 composition. The potential energy (eV) is rescaled against its value E0 of the structure at 0 Kelvin. The Ih undergoes to a structural change at 800 K.
  • CALPHAD thermodynamic prediction of the melting temperature depression of elemental Cu, Pt and bimetallic CuPt nanoalloys at 1:1 composition. Thin lines refer to the bulk melting limit for pure metals and its alloy.

The effects of surfaces on the catalytic activity of metallic systems were/are approached by thermodynamic modelling of surface energy and surface concentration by using Strohl-King multilayer model and quasi-chemical approximation (QCA) for regular solution model. The results obtained are comparable (> 4 nm) to those calculated by MD simulations. Modelling of gas permeation through solid metallic alloys (first Fick law) is approached using the finite difference method. Original software has been developed in Matlab environment.


Bi-Sn NPs: Particle size vs. Tmelting a) Tin; b) Bismuth; Nanosized Bi-Sn phase diagram
    nanosized metallic systems catalysts Pb-free solders biomedical alloys calphad thermodynamic and kinetic modelling thermophysical properties

    • S. Delsante, G. Borzone, R. Novakovic, D. Piazza, G. Pigozzi, J. Janczak-Rusch, M. Pilloni, G. Ennas
      Synthesis and thermodynamics of Ag-Cu nanoparticles
      Phys. Chem. Chem. Phys., 17 (2015), 28387-28393
    • F. Frongia, M. Pilloni, A. Scano, A. Ardu, C. Cannas, A. Musinu, G. Borzone, S. Delsante, R. Novakovic, G. Ennas
      Synthesis and Melting Behaviour of Bi, Sn and Sn-Bi Nanostructured Alloy
      J. Alloys & Compds., 623 (2015) 7-14
    • L. Pavan, F. Baletto, R. Novakovic
      Multiscale approach for studying melting transitions in CuPt nanoparticles
      Phys. Chem. Chem. Phys., 17 (2015) 28364-28371
    • D. Bochicchio, R. Ferrando, R. Novakovic, E. Panizon, G. Rossi
      Chemical ordering in magic-size Ag-Pd nanoparticles
      Phys. Chem. Chem. Phys., 16 (2014) 26478-26484

    • Actions COST 531 (2002-2007), COST MP0602 (2007-2011), COST MP0903 (2010-2014), COST TD1409 (2015-)

    • DCCI, Università di Genova
    • DIFI, Università di Genova
    • DSCG, Università di Cagliari
    • King's College, London
    • EMPA, Dübendorf