BLACK Ni-BASED GALVANIC COATINGS

摘要

In recent years, black nickel-based functional coatings are increasingly being used as a worthy alternative to chromium coatings on steel, since such coatings provide not only an aesthetic appearance, but also effective corrosion protection.The known technologies of applying black nickel coatings do not allow obtaining coatings with the required corrosion and wearing resistance. In addition, these technologies involve the mandatory pre-deposition of copper or nickel underlayer. The aim of the present work is the improvement of the technological process of applying black nickel coatings. Plates of cold-rolled steel were used as samples. A stepwise method of the cathode current density change for deposition of black nickel-containing coatings is proposed. Electrodeposition was carried out from a solution of the following composition, g / I: NiSO_4 - 7H_2O - 100; (NH_4)2SO_4 - 15; ZnSO_4 - 7H_2O - 40; NH_4CNS - 15; H_3BO_3 - 25.