The Role of Microstructure in Hydrogen Permeation in Palladium and Pd_(77)Ag_(23) Alloys

摘要

Hydrogen transport is a structure sensitive property. The microstructure and defects of polycrystalline metals can affect hydrogen diffusion. The effects of microstructure of cold rolled and annealed Pd and Pd_(77)Ag_(23) alloys on hydrogen desorption and permeation have been investigated. When increasing the amount of deformation in palladium, hydrogen permeation in palladium will be more delayed. The deformation caused a substantial reduction of hydrogen diffusion because deformation has increased defect density and changed microstructure in the investigated materials. The solubility in deformed palladium and Pd_(77)Ag_(23) is increased. After annealing at 250°C and 850°C, microstructures of Pd_(77)Ag_(23) alloy not only have been changed, but the densities of defects have decreased as well These changes also affect hydrogen permeation and desorption. The deformed microstructure and defects play an important role in controlling the hydrogen permeation in Pd and Pd_(77)Ag_(23) alloys.