Nuclear reaction analysis of helium migration in zirconia

We have studied helium migration in monoclinic (α-ZrO2) and cubic yttria-stabilized zirconia, YSZ (ZrO2:Y) from non-destructive 3He depth profiling using the resonant 3He(d, p)4He nuclear reaction. Results have been obtained on polycrystalline α-ZrO2 ceramics and YSZ single crystals implanted with 3-MeV 3He ions at a depth around 7 μm then isochronously annealed in air at temperatures between 200 and 1100 °C. In α-ZrO2, no change of the depth profile is found up to 800 °C. In contrast, two regimes are found in YSZ: (i) below 800 °C, diffusion is controlled by helium trapping at native oxygen vacancies (≈10 at.%), (ii) above 800 °C, helium escapes out of the profile, with almost complete outgassing at 1100 °C.