Electrolytic coating of iron-chromium alloy of sulphate-chloride electrolyte in machine parts recovery process modelling

Abstract

Introduction. The technological process of restoring a part should provide more than 80% of the resource and no more than 50% of the cost of a new part. The wear resistance of the applied coating determines the resource of the restored part operating under waterjet and boundary friction. The microhardness of an iron-based electrolytic coating is one of the key indicators of wear resistance. The study of the results of statistical processing and the factors most affecting the increase in the microhardness of the iron-based coating will make it possible to recommend and optimize the deposition conditions for obtaining the most wear-resistant coatings.Materials and methods. The studies on equipment that let to obtain the necessary data with the required accuracy were carried out. The mathematical processing using modern statistical data processing tools that excluded possible errors, let to obtain the dependence of factors with the necessary accuracy was carried out.Results. During the study of the developed sulfate-chloride electrolyte for the deposition of an iron–chromium coating, it became necessary to determine the effect of deposition conditions – ‘factors’ (temperature, acidity of the electrolyte, cathode current density) on the microhardness of the coating – ‘response’. It was found that the combination of the factors ‘temperature’ and ‘cathode current density’ in the coded values of 1.5. 2.0 and -2 are the most significant. The deposition conditions in order to obtain a coating with maximum microhardness are optimized.Discussion and conclusions. As a result of the conducted studies for the effect of the deposition conditions  of the Fe-Cr alloy from the sulfate-chloride electrolyte on the microhardness of the coating, it was found that in order to obtain high-quality coatings of the iron-chromium alloy with high microhardness, it is necessary to strictly comply with the requirements of the deposition conditions and acidity to a greater extent. As the current density and temperature of the electrolyte, compared with the acidity of the electrolyte, iron baths are installed and regulated by equipment.