The metallic manufactures should be separated into objects consisting of a single metal, such precious (copper, gold, silver), and objects made of metallic alloys, much more workable and resistant, such as bronze, pewter, electro. The first purpose of the diagnostic research is therefore to investigate the nature of the manufacture and possibly to characterize the alloys (for example, there are several bronzes, with different contents of copper: knowing these values allows to define the resistance of the alloy, but also the period and the area in which has been melt). Then, the analysis concerns the state of conservation, the patinas and any corrosion products on the surface.
Among the techniques available for such investigations, some are non-destructive, such as portable X-ray fluorescence which gives information about the surface composition, or the conductivity measurement IACS to evaluate the homogeneity of the alloys, the induced currents or the ultrasounds to detect cracks and gaps and to measure the thickness of the patinas. For the solution of structural problems can also apply the modelling of finite elements analysis.
Other non-destructive techniques applied to the study of metallic manufactures are the thermovision and the x-ray radiography, while for the X-ray diffraction, and the electron microscopy observation with micro-analysis and FT-IR spectrometry, useful for an elemental analysis of metals and degradation products, it is necessary a specimen of material. The diffraction, together with the atomic absorption spectrometry, is also used for the study of the casting cores of statues finished by the technique of lost wax.