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Tribocorrosion behaviour of niobium nitride/niobium multilayer in contact with ringer lactate

Abstract:

Multilayer coatings with Niobium nitride/niobium were deposited on stainless steel AISI 316 LVM by a multi-target system magnetron sputtering, from Nb targets of high purity (99,99%) in an atmosphere of Ar/N2, with bilayer periods in the range from 1 to 50, with the purpose to study the variation of the multilayers in function of the mechanical and electrochemical response. The performed tests were corrosion and tribo-corrosion using electrochemical impedance spectroscopy, in both cases the used electrolyte was ringer lactate at 37° C. The corrosion behavior was evaluated by the Bode diagrams, in order to study its effect on the structure and the electrochemical properties. The AISI 316LVM stainless steel is utilized for medical applications due to it is melted under vacuum, generating a high purity grade which is required for the surgical prostheses. Moreover, the 316 LVM steel offers an excellent resistance to the tissues, physiological fluids, intergranular corrosion and the corrosion in general. However, its performance as biomaterial is questioned by its nickel content. Specimens of AISI 316 LVM coated with NbN/Nb were characterized using electrochemical impedance spectroscopy (EIS). It was found a dependence of the bilayers number on the corrosion resistance for the NbN/Nb films.