In situ HREM observation of the oxidation of nickel thin foils

Growth of oxide microcrystals at the edge of nickel grains could be observed using high-resolution microscopy. Three types of samples were examined: a nickel-cermet material, and pure annealed nickel, both ion-beam milled; and a standard electropolished nickel foil. Microstructural features, such as crystallite size, facets, orientation relationship and lattice parameter are described. The observations were performed with a JEOL 4000 EX II microscope. The point resolution at 400kV is 1.6{angstrom}. The largest interplanar spacing in Ni is 2.03{angstrom} = d(111), and is the only imaging axis which allows lattice imaging.