The Study on the Anti-corrosion Performance of NiTi Alloy in Human Body Solution with the Fabricating Processes of Laser Irradiation and PDMS Modification

Chengjuan Yang,Yanling Tian,Weiran Cao,Xiubing Jing,Zhen Yang,Meng Wang

doi:10.1007/s42235-021-0011-5

Abstract

This paper presents a new and safe method of fabricating super-hydrophobic surface on NiTi Shape Memory Alloy (SMA), which aims to further improve the corrosion resistance performance and biocompatibility of NiTi SMA. The super-hydrophobic surfaces with Water Contact Angle (WCA) of 155.4° ± 0.9° and Water Sliding Angle (WSA) of 4.4° ± 1.1° were obtained by the hybrid of laser irradiation and polydimethylsiloxane (PDMS) modification. The forming mechanism was systematically revealed via Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The anti-corrosion of samples was investigated in Simulated Body Fluid (SBF) via the potentiodynamic polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) tests. PDMS super-hydrophobic coatings showed superior anti-corrosion performance. The Ni ions release experiment was also conducted and the corresponding result demonstrated that the super-hydrophobic samples effectively inhibited the release of Ni ions both in electrolyte and SBF. Besides, biocompatibility was further analyzed, indicating that the prepared super-hydrophobic surfaces present a huge potential advantage in biocompatibility.

Highlights

Nitinol Shape Memory Alloy (NiTi SMA), possessing special performance such as wear resistance, super-elasticity, Shape Memory Effect (SME) and biocompatibility has drawn wide attention in recent years[1]
It has been reported that Ni ions at a high level in the human body can induce the occurrence of adverse reactions such as toxicity, anaphylaxis, chronic inflammation and so on[4], which severely restricts the development of NiTi SMA as medical equipment
The results of Fig .4 showed that NiTi-I surfaces exhibited intrinsic hydrophilicity with a small Water Contact Angle (WCA) of 68.2 ̊ ± 2.3 ̊ and high Water Sliding Angle (WSA) of 90 ̊

Summary

Introduction

Nitinol Shape Memory Alloy (NiTi SMA), possessing special performance such as wear resistance, super-elasticity, Shape Memory Effect (SME) and biocompatibility has drawn wide attention in recent years[1]. Enhancing the corrosion resistance and biocompatibility of NiTi SMA plays a vital role in its application in medicine and has attracted plenty of attention in recent years. The corrosion behavior and bioactivity of HAp coatings were evaluated through electrochemical potentiodynamic polarization tests in Ringer’s solution and immersion tests in Simulated Body Fluid (SBF). They have demonstrated that the HAp coatings with superior anti-corrosion and bioactive could be obtained via optimizing process parameters in the electrodeposition[7]. The coating could obviously mitigate the Ni ion release from NiTi SMAs after immersion in artificial saliva[8] The former method of deposition coatings is high cost and inapplicable

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Results

Conclusion