Electrodeposition and properties of cyclically modulated silver-antimony alloys

An investigation was carried out on the influence of electrodeposition conditions on the properties of cyclically modulated Ag-Sb alloys, such as internal stress, microhardness, roughness, electrical contact resistance, wear resistance and plug-in forces. Pulses of different amplitude and duration were used, leading to different composition and thickness of the deposited sublayers, and the resulting changes in the coating properties were demonstrated. The possibility of depositing coatings free of internal stress is shown. The electrical contact resistance does not depend on the multilayer structure of the coating, but on the type and properties of the upper sublayer. The microhardness of the multilayer coatings increases with the increase in their antimony content. It decreases for very short pulses whereby the effect of the higher current density cannot be realized. The wear resistance of the multilayer coatings displays values between those of the respective monolayer coatings deposited under the conditions of separate sublayer deposition. It increases at a very small sublayer thickness, at decreasing contribution of the higher current density and at lower stress values of the multilayer coatings. The roughness of the coatings is not influenced by their multilayer structure, and the plug-in forces increase with the reduction of the sublayer thickness to about 0.03 mum.