Vasil'eva E. Electrodeposition of antifriction coatings based on lead from methanesulphonate electrolytes

The object of investigation is electrodeposition of antifriction coatings on the base of lead. The goal of investigation is development of scientific and technical basis of the modern, highly intensive and environmentally-friendly technology for obtaining antifriction coatings of lead-tin and lead-tin-copper alloys using methanesulphonate electrolytes as well as its industrial implementation for fabrication of bearing shells. Methods of investigation are as follows: voltammetry, polarography on dropping mercury electrode and gravimetry (for ascertainment of the regularities of lead alloys electrodeposition); amperometric and redox titration (for analyses of electrolyte as well as alloys compositions); tribotechnical investigations, hardness measurements, X-ray diffraction method, optical microscopy and scanning electron microscopy (for determination of the properties, structure and morphology of the coatings). Theoretical an practical results are as follows: the mechanism of simultaneous discharge of Pb2+, Sn2+ and Cu2+ ions from methanesulphonate electrolytes in the presence of organic additives was suggested which develops the theory of electrolytic co-deposition; effect of various factors on the elelectrodeposition of alloys based on lead as well as on the coatings properties was established that is the scientific basis for development of novel resource-saving and energy-efficient technologies of antifriction coatings electrodeposition with predictable properties; innovation technique for obtaining of antifriction coatings on the base of lead on the bearing shells was elaborated using methanesulphonate bath, this technique having been realized at the Melitopol Factory of Plain Bearings, Ltd. Novelty of the points and results is as follows: is was stated for the first time that the electrodeposition of eutectic Pb-Sn alloy from methanesulphonate electrolyte does not obey the regularities of independent discharge of the components, this phenomenon being connected with inhibition of the partial process of tin electrodeposition on foreign lead substrate; introduction of oxyethylated b-naphthol to the methanesulphonate electrolyte results in electrode surface modification and decreasing the tin co-deposition polarization that allows enlarging noticeably tin content in alloy as well as improving considerably surface appearance of the coatings obtained; an essential decrease in the rate of Sn2+ ions chemical oxidation was shown for the first time in methanesulphonate electrolyte in the presence of Cu2+ ions when a sulphonated derivative of an aromatic amine was used. Implementation degree - the technology proposed was successfully realized at the Melitopol Factory of Plain Bearings, Ltd. It is recommended for the further introduction to enterprises of machine building such as "Zaporozhe engineering works", public corporation and "Motor Sich" JSC.