In situ XRD characterization of hydrogen desorption from electrochemically deposited Pd coating

One of the main problems in electrochemical Pd deposition of coatings is the hydrogen desorption that causes microcracking phenomena. With the aim of understanding the structural changes due to the hydrogen desorption, the kinetics of the phase transformation from hydride to metallic structure has been followed by in situ X-ray diffraction (XRD) experiments. The structural evolution of samples obtained by two different electrochemical baths has been compared. It was found that the solubility and the desorption kinetics of hydrogen are significantly influenced by the presence of structural defects. Residual stresses have been evaluated for both samples by means of 2D X-ray diffraction (XRD²). The presence of amine complexes in the bath seems to contribute to reducing the crystalline dimension of the Pd-phase, and the differences between the specific volumes of α and β phases is reduced for nanostructured coatings.