Influence of the Surface Quality of Substrates during Electrospark Deposition

Abstract

The deposition of protective coatings can significantly improve the corrosion resistance and tribotechnical behavior of the surface of metal parts. Surface preparation before a coating deposition increases the cost per unit area of coating. Substrates were prepared from steel St3 with the sur-face roughness Ra from 0.01 to 0.597 µm, as well as with a rust layer, and the electrospark deposition (ESD) of a Cr-Fe-Cu coating was carried out. The conducted studies lead to the conclusion that the initial surface roughness of St3 steel in the Ra range from 0.01 to 0.597 µm does not affect the material deposition nature during ESD and the structure of the deposited coatings. This is unambiguously confirmed by the data on oxidation resistance and tribological behavior of coatings. With this in mind, it can be concluded that the method of ESD with a non-localized electrode with the addition of chromium powder provides high reproducibility of the deposited coatings. ESD can clean the rust layer to some extent, but it is not possible to completely get rid of it, and large pores are present in the formed coating. This was reflected in a significant decrease in the oxidation resistance and the wear resistance of the coatings.