STRUCTURE AND PROPERTIES OF COATING BASED ON SILVER, NICKEL AND NITROGEN FORMED BY THE COMBINED METHOD ON COPPER
Combined technologies that combine various methods of influencing the structure and properties of a material are currently one of the intensively developing areas of modification of metals and alloys. In this work, we studied the structure and properties of a coating based on silver, nickel, and nitrogen formed on copper by a combined method combining electroexplosive spraying of a coating based on silver and nickel, irradiation with a pulsed electron beam, and subsequent nitriding in a low-pressure gas discharge plasma. Electroexplosive spraying was carried out in a mode providing heating of the copper substrate to the melting temperature. The choice of modes of electron-beam processing was based on the fact that to ensure the maximum depth of fusion of the electroexplosive coating without evaporation. Nitriding was carried out in order to form nitrides used for spraying materials. The coating thickness is up to 80 microns. It is shown that the wear resistance of the coating exceeds the wear resistance of copper by 13%; the coefficient of friction of the coating is 3,5% lower than that of copper; the hardness of the coating exceeds the hardness of copper by 13%. It was found that the main element of the coating is silver; nickel and copper are present in much smaller amounts. A transition layer up to 8 μm thick, enriched with nickel atoms, was revealed between the coating and the substrate. It is shown that the coating is formed by solid solutions based on copper, nickel and silver, and also contains nickel, silver and copper nitrides. It has been revealed that the phase composition of the coating substantially depends on the energy density of the electron beam (at constant values of the duration and number of pulses of the beam exposure). In the future, the use of the proposed coating will reduce the metal consumption of the production of electrical contacts.