Funct. Mater. 2026; 33 (2): 269-274.
Influence of fractal structure on the resource increase of ion-plasma and thermodiffusion Ni–Co–Cr–Al–Y coatings
1Kharkiv National Automobile and Highway University, 25 Yaroslava Mudrogo Str., 61002 Kharkiv, Ukraine
2Prydniprovska State Academy of Civil Engineering and Architecture, 24a Architect Oleh Petrov Str., 49000 Dnipro, Ukraine
A technology for applying multifunctional protective ion-plasma and thermodiffusion coatings of the Ni–Co–Cr–Al–Y system has been developed and optimized. Ion-plasma coatings of the Ni–Co–Cr–Al–Y system, formed by electron-beam atomic-ion sputtering in vacuum with cyclic variation of substrate potential and temperature, make it possible to increase the corrosion resistance at least twofold compared to previously used analogues. Thermal diffusion coatings of the Ni–Cr–Al–Si–REM system provide effective protection against high-temperature corrosion and are recommended for industrial implementation. A full cycle of comprehensive tests was carried out, including thermal cycling durability, corrosion resistance in diesel fuel combustion products, molten sodium sulfate, and synthetic ash, as well as long-term service life tests. The microstructure of the ion-plasma condensates is characterized by a layered quasi-amorphous structure. For its quantitative assessment, fractal analysis was used for the first time, which allowed establishing the fractal dimension of the layer boundaries in the range of 1.67–1.83. This explains the increased diffusion stability and adhesion of the coatings.