Thermally Stimulated Evolution of the Surface of Ni- and Cu-Containing Plasma-Electrolytic Oxide Coatings on Titanium

Resumo

The effect of the temperature of annealing in air on the surface architecture and composition of oxide layers has been studied. Copper-enriched nanosized crystals of triangular shape are present on the surface at the annealing temperatures of 500–700°С. Rectangular nano- and microcrystals of a possible composition of NiWO₄ are formed on the surface after annealing at 750–850°С. Nanowhisker brushes, similar in composition to nickel titanates, cover the surface after annealing at 900–950°С. Transformation of the surface architecture and composition on the micro- and nanolevels correlates to the coatings’ activity in the catalysis of the reaction of oxidation of CO to CO₂.