Metallographic aspects of seizure of nickel-containing electrodes during coating deposition under low-voltage pulsed discharged

Abstract

The conditions of seizure of electrodes from Ag-Ni composites, namely SN–10 and SN–30, have been studied in the course of contact deposition of coatings on a copper plate using a low-voltage pulsed discharges. It has been established that all of the studied electrodes including those from cast silver undergo seizure to different degree depending on the conditions of contacting. The manifestation of seizure increases with increasing the nickel content in the composition and, for the same composition, with increasing the concentration and size of the Ni phase in the electrode working layer. This makes the electrode erosion similar to that of cast nickel electrodes. Also, herein the kinetics of coating formation is reduced. The results of metallographic examination confirm the determining role of thermophysical properties of nickel and surface properties of nickel melt in the process of seizure of nickel-containing electrodes.