Microprotrusions evolving from palladium subsurface deuterium-implanted at a cryogenic temperature

Microscopic protrusions are shown to emerge from the Pd subsurface D-ion implanted at liquid-nitrogen temperature. Cross-sectional transmission electron microscopy has revealed that the protrusions were amorphous, suggesting that they were in a molten state during D-ion implantation. The amorphous area of the protrusion was commonly covered with a crystalline shell, the lattice of which expanded from the pure Pd lattice by around 5% that is in an agreement with previous works. The shell might have been of a deuteride structure stable in low-pressure ambiences.