Surface treatment of NiTi shape memory alloy and its influence on corrosion behavior

Vojtěch, Dalibor; Fojt, Jaroslav; Joska, Luděk; Novák, Pavel

doi:10.1016/j.surfcoat.2010.05.010

Cited by 34 publications

(20 citation statements)

References 19 publications

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“…The above finding is directly related to the surface oxide film as a barrier against dissolution of nitinol. It has been proved that improvement of corrosion resistance is directly related to the reduction of nickel release 19) . The Ni release during cell culture was analyzed in detail by atomic absorption spectroscopy by Jafar Khalil-Allafi et al 20) .…”

Section: Discussionmentioning

confidence: 99%

Phase Transformation and Corrosion Properties of Surface Oxidized NiTi Shape Memory Alloy

Wang

Komori

Maeda

et al. 2011

J. Hard Tissue Biology.

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Oxide film was obtained on a NiTi shape memory alloy by a chemical method. The influences of surface oxidation on the phase transformations and corrosion resistance were assessed. Light blue oxide film formed on the alloy was mainly composed of TiO 2 . Differential scanning calorimetry(DSC) measurement displayed that the phase transformations was not affected by surface oxidation. Electrochemical tests indicated that the oxidized NiTi alloy showed better corrosion resistance than the non-oxidized one in the simulated body fluid. Scanning Electron Microscopy (SEM) revealed that lower pitting corrosion occurred for the oxidized NiTi alloy compared with the non-oxidized. The oxidized samples did not show any surface alterations except very small and homogeneously distributed pits were observed.

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Section: Discussionmentioning

confidence: 99%

Phase Transformation and Corrosion Properties of Surface Oxidized NiTi Shape Memory Alloy

Wang

Komori

Maeda

et al. 2011

J. Hard Tissue Biology.

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“…Subsequently, the samples were heat treated at different temperatures in a muffle furnace in air atmosphere: 530 °C and 570 °C [11][12][13] . The samples were exposed to different heat treatment durations: 6, 20, 60, 240 and 480 minutes and thereafter the samples were characterized.…”

Section: Methodsmentioning

confidence: 99%

Oxide Formation on NiTi Surface: Influence of the Heat Treatment Time to Achieve the Shape Memory

et al. 2015

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Several studies regarding superficial treatments of Nitinol (NiTi) shape-memory have been developed aiming to the improve corrosion resistance and to block the Ni release to adjacent tissues. The necessary heat treatment to achieve the shape memory effect normally occurs at temperatures between 500 and 600 °C. However, titanium oxide (TiO 2 ) is formed on the NiTi surface during the shape memory process heat treatment. In this work the effects of the heat treatment time on the surface characteristics of the formed NiTi oxide, at temperatures that promote the shape-memory (530 and 570 °C), were evaluated. The TiO 2 layers which were obtained were evaluated by X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscope (SEM), thermogravimetric analysis (TGA), wettability and roughness. The results show that by increasing the exposure time at the temperature of 570 °C the formation of a thicker oxide is promoted, with less superficial roughness and of a hydrophobic nature. According to the literature, these characteristics indicate that the obtained oxide layer has properties that accelerat the osseointegration process.

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“…This selectivity implies that the Ti contained within the alloy is preferentially oxidized when heated it in air, resulting in the formation of a TiO 2 layer. Vojtěch et al reported that a TiO 2 layer was formed on NiTi alloy by heating it in air at 803 K, 14) and Wu et al reported that a TiO 2 layer was prepared on NiTi alloy by heating it in air at 723 K. 15) These reports revealed that TiO 2 layers could be formed through heating. However, in those studies, the purpose of the formation of TiO 2 layers was to create brier for Ni ion diffusion to the human body, and the photocatalytic activity of the layers was hardly discussed.…”

Section: ¹1mentioning

confidence: 99%

Photocatalytic Activity of the Oxide Layer Formed on NiTi Surface through Thermal Oxidation Process

et al. 2014

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In the present study, we attempted to prepare a photocatalytic titanium dioxide (TiO 2 ) layer on nickel-titanium (NiTi) alloy surface through a simple thermal oxidation process in air. At 723 K, an amorphous TiO 2 layer including a slight amount of Ni was formed on the surface. Above 873 K, the TiO 2 layer crystallized into a rutile phase. At 1023 K, a complex oxide of NiTiO 3 was also formed. The methylene blue degradation test for evaluating photocatalytic activity showed that the formed TiO 2 layers act as photocatalyst under ultraviolet (UV) light illumination, and its activity is superior to that of the surface layer formed by oxidizing a pure Ti substrate. The adhesion strength of the surface layers formed at 723 K on NiTi alloy was higher than that of a commercially available TiO 2 -coating. We conclude that thermal oxidation as a surface modification technique is expected to make NiTi alloys give photocatalytic activity.

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Surface treatment of NiTi shape memory alloy and its influence on corrosion behavior

Cited by 34 publications

References 19 publications

Phase Transformation and Corrosion Properties of Surface Oxidized NiTi Shape Memory Alloy

Phase Transformation and Corrosion Properties of Surface Oxidized NiTi Shape Memory Alloy

Oxide Formation on NiTi Surface: Influence of the Heat Treatment Time to Achieve the Shape Memory

Photocatalytic Activity of the Oxide Layer Formed on NiTi Surface through Thermal Oxidation Process

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