Samara University, Samara, Russia

O. S. Bondareva, Cand. Eng., Associate Prof., Dept. of Metal Technology and Aviation Materials Science, e-mail: osbond@yandex.ru
O. S. Dobychina, Postgraduate Student, Dept. of Metal Technology and Aviation Materials Science, e-mail: o.dobychina@zvpm.ru
M. O. Dmitrieva, Postgraduate Student, Dept. of Metal Technology and Aviation Materials Science, e-mail: mdmitr1ewa@yandex.ru

Samara University, Samara, Russia¹ ; Siberian State Industrial University, Novokuznetsk, Russia²
S. V. Konovalov, Dr. Eng., Prof., Dept. of Metal Technology and Aviation Materials Science¹, Vice-rector for Scientific and Innovative Activities, Head of the Dept. of Mechanics and Mechanical Engineering², e-mail: konovalov@sibsiu.ru

The elemental composition and structure of zinc coatings obtained by galvanizing, hot-dip galvanizing in zinc melt and galfan Zn + 5 % Al melt, thermal diffusion galvanizing, and gas-thermal spraying of zinc powder have been studied. And also the structure and elemental composition of the zinc lamellar coating and the ZINKER coating on a polymer binder were studied. Metallographic studies have shown that the surface and structure of zinc coatings depend on the coating method. By the method of energy-dispersive X-ray spectral microanalysis, it was found that the zinc content on the surface of the coatings differs. The surface of the coating obtained by hot-dip galvanizing at 450 °C is practically pure zinc, on the surface of the high-temperature hotdip zinc coating and the thermal diffusion zinc coating there are iron-zinc phases with different ratios of iron and zinc, the rest of the coatings have impurity elements on the surface, which is associated with the conditions for their preparation. To predict the electrochemical properties of the coatings, their standard electrode potentials were measured. A number of chemical stresses for various zinc coatings have been built. It has been established that in the case of contact of zinc coatings with each other in the presence of an electrolyte, the following variants of electrochemical interaction can be realized. Zinc lamellar coating, ZINKER coating and Galfan are oxidized in a galvanic pair with hot-dip galvanized products at 450 °C, providing cathodic protection. Thermal diffusion zinc coating does not form a galvanic couple with hot zinc coating. Galvanic, gas-thermal and high-temperature hot-zinc coating is restored in pair with hot-zinc coating. The data obtained must be taken into account when using products with various zinc coatings in the joints of parts.

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