STUDY OF THE CORROSION RESISTANCE OF CU(CO,NI)BI2 O4 FILMS WHEN EXPOSED TO AGGRESSIVE ENVIRONMENTS

Abstract

The work examines the effect of substitution of copper with cobalt and nickel in the composition of CuBi2 O4 films obtained using the electrochemical deposition method. The substitution was initiated by addition of cobalt or nickel sulfates to the sulfuric acid electrolyte solution, which made it possible to obtain films with a tetragonal type of crystal lattice characteristic of the CuBi2 O4 phase. Moreover, an analysis of the structural parameters and changes in the elemental composition of the films showed that the addition of nickel and cobalt sulfates to the electrolyte leads to the formation of a tetragonal phase according to the type of substitution associated with the partial replacement of copper by nickel or cobalt, depending on the composition of the electrolyte solution. During simulation of the film degradation processes under external influences, the results of corrosion tests of CuBi2 O4 films in the aggressive environment of a model solution of 0.1 M NaCl at different ambient temperatures were obtained. The dependences of changes in the structural ordering degree and the softening degree of the films under study were determined depending on the time spent in an aggressive environment. The substitution of copper with cobalt or nickel has been found to increase the resistance of the studied films to degradation and oxidation, indicating a positive substitution effect, reducing the degradation rate of the surface of the films in contact with the aggressive medium.