Multilayer coatings of TiNiNb shape memory alloys

Adrian Kiss 1Mariana T. Braic 1Mihai Balaceanu 1Alina Vladescu 1Petra Drob 2Viorel Braic 1

1. National Institute for Optoelectronics (INOE), 1 Atomistilor Str., Bucharest 77125, Romania
2. Romanian Academy, Institute of Physical Chemistry "I.G.Murgulescu" (IPC), Splaiul Independentei 202, Bucharest 77208, Romania

Abstract

TiNiNb shape memory alloy has been used extensively as a material for medical implant devices due to its shape memory effect, superelasticity and biocompatibility. Due to its relatively high amounts of nickel it is not adequate for implants and prosthesis. Therefore, in the last years, the PVD coating methods have become a good choice to prevent the nickel release from substrate composition, as the obtained protective films may present high protection against corrosion and good wear properties.

In this paper, samples of TiNiNb alloy were coated with two types of multilayer coatings (TiN/NbN and TiC/NbC) in order to improve their corrosion resistance and drop the nickel release in artificial physiological solution, without sacrificing their shape memory effect and superelasticity. The Ni ions release of the coated and uncoated samples was investigated. The films were deposited onto TiNiNb alloy by vacuum arc deposition technique under various deposition conditions. In order to have a more complete characterization of the investigated coatings, other properties such as elemental and phase composition, morphology, texture, microhardness and adhesion were investigated. The corrosion tests revealed that all the coated samples were characterized by very low anodic currents in the passive region and by an exceedingly low metal ion release rate. The obtained results suggest that nanostructured multilayered coatings based on Ti and Nb nitride and carbide obtained by vacuum arc deposition can improve the performance of TiNiNb alloy for biomedical applications.

 

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Presentation: Poster at E-MRS Fall Meeting 2006, Symposium A, by Mariana T. Braic
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-20 12:22
Revised:   2009-06-07 00:44