On the resistance of silver migration in Ag-Pd conductive thick films under humid environment and applied dc field

Silver migration occurring in pure silver conductive thick films was minimized by using Ag-Pd alloys. The in situ microscopic observation, under humid environment and an applied d.c. field, showed that the out-growth of silver dendrites from the cathode decreases with increasing (5-20%) amount of Pd in the Ag-Pd specimens, and ceases completely at 30% Pd. The enhancement of silver migration resistance with increasing Pd concentration in Ag-Pd conductors was evident by the measurements of the short circuit current between a couple of thick-him electrodes in distilled water at 5 V. Through the study of anodic potentiodynamic polarization in 0.01 M NaOH and the examination of the surface films on the thick films by X-ray diffraction and surface analyses (Auger and ESCA), it was found that the anodic formation of PdO blocks the silver dissolution, and minimizes the occurrence of silver migration.