A.Kiss, M.T. Braic, M. Balaceanu, A. Vladescu, C. M. Cotrut, V. Braic, Multilayer coatings of TiNiNb shape memory alloys,Reviews on Advanced Materials Science,  15 (2007) 259-263

Title: Multilayer coatings of TiNiNb shape memory alloys

Abstract:The paper presents the results related to the improvement of the corrosion protection and wear behavior of the TiNiNb shape memory alloy, when coated with mono and multilayer films of some transition metal nitrides (TiN, ZrN, (Ti,Zr)N, TiN/ZrN), using the cathodic arc deposition method. The corrosion and wear tests were conducted in an artificial physiological solution. Additional information on the film characteristics was obtained by Auger electron spectroscopy (AES) and X-ray diffraction (XRD) analyses, microhardness measurements and adhesion tests. The differential scanning calorimetry test revealed that the shape memory effect of the substrate was not affected by the coating. The obtained results suggest that mono and multilayered coatings based on Ti and Zr nitrides obtained by vacuum arc deposition can improve the performance of TiNiNb alloy, used for biomedical applications, without sacrificing their shape memory effect.

Key words: magnetron deposition; films; corrosion protection; hard coatings; steel; wear.