Trapping and surface recombination of ion-implanted deuterium in stainless steel

Nuclear-reaction analysis was used to investigate the behavior of deuterium (D) in three austenitic stainless steels following ion implantation with D and He. The D was bound to irradiation defects with a binding enthalpy of 0.23±0.08 eV relative to solution sites. Helium bubbles of diameter ∼1 nm trapped D with a binding enthalpy of 0.42±0.08 eV, presumably through a chemisorptionlike process at the bubble walls. Surface-controlled release of D to the gas phase was characterized over the temperature range 425–575 K, and the rate was found to be proportional to the square of the solution concentration within the matrix. Electropolish oxide reduced the surface release rate by as much as 1000 times from that of an ion-sputtered surface.