Highly Biocompatible Porous NiTi Alloys

Tejal A Raval ,I B Patel

doi:10.14331/ijfps.2020.330135

Tejal A Raval , I B Patel

Open Access

https://doi.org/10.14331/ijfps.2020.330135

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Abstract

Nickel Titanium alloys have proved to be a perfect choice for materials used for medical devices like catheters, pacemakers and stone removal mesh. However, there are some challenges related to the shape and size modifications required to suffice the applications. The alloy needs improvements particularly in the areas of porosity for bone replacement, radiopacity, super elasticity and fatigue strength. There is a wide range of applications of biocompatible Porous NiTi alloys in the areas of inter body fusion devices, synthetic bone grafting, etc. Although it cannot be denied of the possibility of high corrosion factor of Porous NiTi alloys as compared to solid NiTinol due to greater surface area in contact with the body fluids. Such cases include definite surface preparation to cater to the need for increased biocompatibility. This paper includes the synthesis of porous NiTi alloys through the sintering process along with a check of the surface treatments and its effects on the properties related to corrosion of Porous NiTinol. The Alloys were subjected to different treatments like dry heating, boiling in water and passivation. The corrosion resistance, after and before the treatments were evaluated.

Highlights

The corrosion susceptibility of surface-treated Porous NiTinol was evaluated by conducting cyclic polarization tests preferably using ASTM F 2129-08 (O’Brien, Carroll, & Kelly, 2002; Thierry, Tabrizian, Trepanier, Savadogo, & Yahia, 2000).This is preferably the currently in vitro method for assessing the corrosion resistance of biologically implantable medical devices, where the difference between the breakdown potential, Eb, and rest potential, Er, is used as a measure of the resistance to corrosion
The super elasticity and shape memory properties of these porous alloys can be an asset in biomedical implants like hip replacement, knee joint replacement and dental implants
The fabrication of Porous NiTi alloy with spherical pore morphology and size was accomplished for biomedical implant application

Summary

Introduction

Comparing the Ti-based shape memory alloys and other alloys like Co-Cr alloys, NiTinol has proved to be the most suitable material for biomedical implants due to its better biocompatibility and low modulus (Pelton, Dicello, & Miyazaki, 2000). The porous NiTi is fabricated by melting NaCl spacer powder through conventional sintering process. Porous NiTi alloys are utilized widely in a variety of medical applications like bone grafting, bone reconstruction, intervertebral fusion devices, stents, tissue repair, and dental implants.

Results

Conclusion