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This study detected and investigated the degradation effects and dynamics of the tin amalgam reflective layer of ancient mirrors. The experimental results have been obtained by different spectroscopic techniques: Light Microscopy, Scanning Electron Microscopy with Energy Dispersive X-ray Microanalysis (SEM–EDS), Atomic Force Microscopy (AFM) and μ-Raman Spectroscopy. The latter two were applied for the first time to characterize the amalgam of ancient mirrors. Amalgam alteration products in form of concentric rings with alternate different compositions of tin oxides have been studied on both the amalgam reflective layer inner surface and on its cross-sections. For the first time SEM images of micro-cross-sections of different amalgam degradation products, such as amalgam “drops” and craters, have been obtained. The size of the nano-particles of tin oxides, as amalgam degradation products, was estimated around 3–8 nm by AFM and micro-Raman, as already previously detected through TEM. Micro-Raman showed the presence of both cassiterite and romarkite nano-crystals forming the concentric rings, as only previously hypothesized. This investigation allowed to obtain further experimental evidence and a more advanced comprehension about the structure and formation phases of the amalgam decay products, giving further support to some statements by previous authors and suggesting some assertions different from the ones of previous studies.

Microwaves at 2·45 GHz have been used to ignite the self-propagating high temperature synthesis of Ni and Al powder mixtures (50:50 at-%) to produce a duplex intermetallic coating on Ti substrates. Owing to the high ß-NiAl synthesis reaction enthalpy and the energy provided by the electromagnetic field, the newly formed aluminide is in the liquid phase. Thus, it can react with the underlying Ti substrate, forming a ternary eutectic at the interface, belonging to the Ni–Al–Ti system. The peculiar interlocking microstructure of such ternary layer is responsible for an increase in toughness and hardness compared to the parent NiAl coating. Moreover, the ternary layer's oxidation resistance was tested, showing the possibility of replacing the functionality of hard and brittle NiAl, but limitedly up to 750°C. This can be ascribed to the relatively low Al content in the ternary layer, which hinders the formation of a continuous and protective Al2O3scale. For this reason, the increase in Al content, or the addition of further elements such as Cr or Si, in the starting powder mixture, helps improve the oxidation resistance of the complex intermetallic coating at the interface, up to the tested temperature of 900°C.

An original inverse extrusion test was developed in order to study the microstructural evolution in the plastic deformation of 6060 and 6082 aluminium alloys. Sample billets were extracted from commercial logs and subjected to plastic deformation in an inverse extrusion process, particularly aimed at producing different strain and strain rate conditions at representative positions within the billet section. Different experiments were performed at various temperatures and strain rates. The particular thermo-mechanical history of each point in different experiments was then reconstructed by FEM analysis. The cups were sectioned and the microstructure was analysed at some representative locations, to relate it to the FEM simulation results.