High resolution alpha spectrometry (AS) is commonly applied for the determination of actinides and other alpha-emitting nuclides in many applications. Electrodeposition is the standard procedure for preparing alpha-particle sources usually made of a thin and uniform radioactive deposit onto a metallic substrate. Natural U sources prepared by the Hallstadius method are known to contain co-deposited Pt from the anode. In this sense, the main aim of this work is to conclusively review the behaviour of Pt and U in the electrodeposition process and their distribution in the resulting deposit, factors that are responsible for the thickness and uniformity of the sources. In addition to new scanning electron microscopy/energy dispersive spectroscopy (SEM-EDX) and X-ray absorption fine structure (XAFS) data, the electrodeposited surface has been analyzed using both atomic force microscopy (AFM) and synchrotron radiation Grazing Incidence X-ray diffraction (GI-XRD). The results concerning morphology of the deposit, surface roughness, topography and surface structure obtained from sources prepared at different electrodeposition times agree with the AS results concerning electrodeposition yield and spectral resolution.