The early stage oxidation of germanium-doped magnesium alloys was investigated via atom probe tomography. A catalytic reaction cell attached to a local electrode atom probe allowed controlled exposure of electropolished specimens to oxygen gas. Prior to exposure, some samples were found to be enriched in hydrogen, thought to be introduced during electropolishing. These samples reacted strongly to form sub-surface phases rich in H and O, while samples with less hydrogen did not. These results suggest that hydrogen in the sample plays an important role as a catalyst to oxidation and may affect the hydrogen evolution rate in Mg alloys.
- Atom probe tomography