A Comparative Assessment of Hydrogen Embrittlement: Palladium and Palladium-Silver (25 Weight% Silver) Subjected to Hydrogen Absorption/Desorption Cycling

The negative effects of hydrogen embrittlement on metallic systems have been investigated through determination of the mechanical properties of two metallic systems that were exposed to hydrogen. An assessment of the effects of hydrogen absorption/desorption cycling on the tensile strength, ductility, and microhardness of pure palladium and the alloy palladium-silver (25 weight% silver) has been undertaken. The variables that are the focus of the study are the amount of hydrogen absorbed by the metal, deuterium isotope effect, number of hydrogen absorption/desorption cycles, and the hydrogen exposure temperature. Under all conditions studied, the mechanical properties of pure palladium were significantly altered as a result of hydrogen exposure, with significant hydrogen embrittlement occurring. In contrast, the mechanical properties of the palladium-silver alloy showed little alteration as a result of hydrogen exposure, including virtually no occurrence of hydrogen embrittlement.