Controllable sealing of leaky alumina films on NiAl(100) surface by catalytic oxidation

We show the oxide films grown by saturated dosing of oxygen on NiAl(100) is leaky, i.e., it has no apparent effect blocking deposited Co from diffusion into the bulk. We then show the easy paths for diffusion (presumably the boundaries between the oxide stripes) can be sealed by an oxidation process catalyzed by Co nanoparticles. Once sealed, the temperature range in which Co nanoparticles persist on the surface is extended by 400 K (up to 1100 K). Such "leak tight" oxide films could serve as better corrosion barrier and insulting layers.