Nickel- and copper-containing oxide films on titanium

We have studied the composition and structure of films 20–30 μm thick prepared by plasmaassisted electrochemical oxidation (PEO) and additionally modified by impregnation in aqueous solutions of nickel and copper nitrates and then annealed. The investigative tools used were powder X-ray diffraction, electron probe microanalysis (EPMA), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy. Unmodified film/titanium composites have a certain catalytic activity in CO oxidation to CO₂ at temperatures above 300°C; for modified layers, these temperatures are noticeably higher. Modification influences the surface structure, relief, and elemental composition. Relations between the composition and catalytic properties of the oxide layers are discussed.