Permeation behavior of deuterium implanted in electro- and sputter-deposited copper coatings on aluminum alloy substrates

Permeation behavior of deuterium in copper coatings (∼6 μm thickness) deposited on Al-6061 substrates by the electro- and the sputter-deposition methods is compared. The electroplated coating contained copper and aluminum phases, and exhibited microcracks that were distributed uniformly all over the surface. The sputtered coating contained Cu9Al4 and CuAl2 phases in addition to copper and aluminum, and was fairly dense. Both the coatings contained oxygen at the free surface and at the coating–substrate interface. Deuterium was implanted in both the coatings under identical conditions and the deuterium profiles were subsequently measured using secondary ion mass spectrometry (SIMS). In case of the electroplated coating, the implanted deuterium diffused into the sample without any interference and reached the oxygen-rich interface where it was trapped by the aluminum oxide. On the contrary, in case of the sputtered coating, the diffusing deuterium was trapped continuously before reaching the oxygen-rich coating–substrate interface. The results are discussed.