Studies of surface modified NiTi alloy

Shevchenko, N.; Pham, M.T.; Maitz, Manfred F.

doi:10.1016/j.apsusc.2004.05.273

Cited by 99 publications

(72 citation statements)

References 14 publications

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“…The effects of oxygen, nitrogen, argon ion and C 2 H 2 plasmas on surface modification of Nitinol were explored [71][72][73][74][75][76][77][78][79][81][82][83][84]. PIII carried out at the 20-50 kV target voltages with the incident dose of 10 16 -10 17 atoms cm À2 , resulted in the alteration of the chemical composition of Nitinol surfaces to a depth from a few hundred nanometers to 2 lm.…”

Section: Oxygen Implantationmentioning

confidence: 99%

Critical overview of Nitinol surfaces and their modifications for medical applications

2008

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Section: Oxygen Implantationmentioning

confidence: 99%

Critical overview of Nitinol surfaces and their modifications for medical applications

2008

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“…Among the methods that were previously used to improve mainly biological properties of titanium and its alloys (Ti6Al4V, Ti6Al7Nb), thermal, alkali and electrochemical treatments are of interest to the authors (Kokubo 1998;Firstov et al 2002;Chen et al 2003Chen et al , 2004Shevchenko et al 2004;Chrzanowski et al 2005;Gu et al 2005;Cheng & Zheng 2006b;Chrzanowski 2006;Shukla & Balasubramaniam 2006;Armitage & Chrzanowski 2007;Kawakita et al 2007;Wen et al 2007). Electrochemical and chemical treatment in conjunction with heat treatment improved the bioactivity through the alteration to the topography, structure and chemical composition of the surface.…”

Section: Introductionmentioning

confidence: 99%

Nanomechanical evaluation of nickel–titanium surface properties after alkali and electrochemical treatments

Chrzanowski

Neel

Armitage

et al. 2008

J. R. Soc. Interface.

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In this paper, the suitability of alkali treatment followed by heat treatment at 6008C, and spark oxidation for nickel-titanium, intended for medical applications such as pins, wires and clamps, was evaluated on the basis of nanomechanical and wear testing. In addition, the chemical composition and topography of the surface layer, wetting ability, corrosion resistance and influence of the heat treatment on structure of the alloy were also investigated. The results showed that the highest hardness was observed for alkali-treated samples, and this could be correlated with the structure of the sample that contained martensite and a higher phase transformation temperature. This treatment caused a very large increase of nickel in the top layer and decreased resistance in pitting corrosion. These results disqualified the treatment to be considered as useful for medical applications. On the other hand, the hardness of the oxidized samples was at the same level as that obtained for ground reference samples. Moreover, the oxide layer was enriched with phosphorus, and it was predominantly composed of TiO 2 and phosphorus oxides. This 3.1 mm thick layer had good adhesion to the substrate as indicated by scratch testing and wear resistant in nanowear testing. However, the oxidation did not significantly increase the corrosion resistance of the alloy compared with reference samples.

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“…19) We considered that the Ni remaining in the surface layer diffused toward both outward and inward directions after forming Ti-oxide because Ni atoms diffuse easily through defective TiO x . 19,20) Consequently, the Ni-rich regions at the topmost surface and beneath the oxide layer formed on NiTi alloy.…”

Section: Characteristics Of the Oxidized Niti Surfacementioning

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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Studies of surface modified NiTi alloy

Cited by 99 publications

References 14 publications

Critical overview of Nitinol surfaces and their modifications for medical applications

Critical overview of Nitinol surfaces and their modifications for medical applications

Nanomechanical evaluation of nickel–titanium surface properties after alkali and electrochemical treatments

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

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