Development of Fe-Ni-W alloys for steel parts coverings

Abstract

The metallic coatings have their importance in the protection of structures against corrosion, gaining relevance as they bring financial benefits to avoid contamination, loss of efficiency, accidents, among other undesirable and costly situations. Electrodeposition is a mechanism used for the application of metallic coatings, and has been widely used industrially for Chromium alloys, which end up being harmful to the environment because of its carcinogenic nature. Thus, this work has as main objective to develop corrosion-resistant Fe-Ni-W alloys, evaluating process parameters such as electrical current density, cathodic rotation and electrolytic bath temperature. The study of the influence of these parameters on the electrodeposition of Fe-Ni-W contemplated the efficiency and rate of deposition. The electrodeposition tests were carried out on previously treated carbon steel substrates, using electrolytic baths with pH adjusted according to a metal speciation study and the application of electric current with the aid of a potentiostat. Fe-Ni-W alloys were characterized by Scanning Electron Microscopy (MEV) with X-ray Dispersive Energy Detector (EDS). The maximum deposition efficiency achieved was 50%. The compositions of Iron and Nickel in the alloy were influenced by variations in temperature and cathodic rotation, with the percentage of Iron being around 40% when using the temperature of 25 oC and the rotation of 15 rpm.