Deuterium diffusion, trapping and release in ion-implanted nickel

A series of implantation/thermal release experiments has been performed on deuterium-implanted polycrystalline nickel which had been pre-implanted with He⁺, B⁺, C⁺, 0⁺or Ni⁺ions. The deuterium was implanted at 180 K: the amount retained and its approximate depth distribution were determined by periodic nuclear reaction analysis (NRA) during thermal ramping of the samples. The retention vs. temperature data were compared to calculations based on a diffusion model in order to extract trap energies and concentrations. Trapping at radiation defects introduced by the 180 K deuterium implantations retarded the diffusional release of deuterium; pre-implantation with He⁺caused a significant increase in the release temperature; pre-implantation of the other ions produced little or no effect on the release temperature, except possibly in the case of C⁺, which may have produced 0.6 eV traps. The He⁺implantation produced traps with an apparent energy of 0.69 eV, which was reduced to 0.59 eV by annealing for 63 h at 605 K.