Deuterium trapping in helium-implanted nickel

Abstract

By means of ion-beam-analysis techniques, the trapping of deuterium implanted into nickel preimplanted with helium was investigated in the temperature range 100–500 K. Following room-temperature helium implantations and deuterium implantations at ∼100 K, linear-ramp annealing (1–2 K/min) was carried out, while the deuterium concentration within the near-surface region (0–0.5 μm) was monitored by use of the nuclear reaction D(3He,α)1 H. The release curves were analyzed by solving a diffusion equation with the appropriate trapping terms. In addition to trapping by lattice defects, stronger helium-associated traps were found with a binding enthalpy of 0.55±0.05 eV relative to a solution site. We propose that the responsible entities are small helium bubbles observed in the implanted material by transmission electron microscopy.