Effect of labyrinth-like arrays formation of nickel nanorods on nickel surface as a result of galvanic substitution reaction in aqueous solutions of CuCl$_2$ and NaCl mixture

The article describes the nickel surface treatment conditions in aqueous solutions of a mixture of CuCl$_2$ and NaCl salts. This investigation reveals the occurrence of selective etching on the nickel surface, facilitated by a galvanic replacement reaction (GRR). The etching process gives rise to the formation of arrays of labyrinths with walls of nickel nanorods with a diameter ranging from 10 to 50 nanometers and a length of up to 0.5 micrometers are formed, located primarily in the direction perpendicular to the surface. The experimental results obtained have enabled the formulation of hypotheses concerning the sequence of chemical reactions occurring on the surface and the role of the A. Turing diffusion-chemical model in the formation of the observed labyrinths. It has been demonstrated that the presence of such labyrinths on the surface of nickel leads to a decrease in the angles of its wetting with water.