Characterization of oxide film formed on NiTi by laser oxidation

Wong, M.H.; Cheng, F. T.; Pang, G.K.H.; Man, Hau Chung

doi:10.1016/j.msea.2006.10.164

Cited by 50 publications

(25 citation statements)

References 33 publications

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“…3(a), the Ti 2p spectrum exhibits two main peaks with binding energies of about 465.0 eV (Ti 4+ 2p 1/2 ) and 459.2 eV (Ti 4+ 2p 3/2 ), indicating that titanium on the surface is mainly in the form of titanium oxide. 23 The intensity of both the 465.0 eV (Ti 4+ 2p 1/2 ) and 459.2 eV (Ti 4+ 2p 3/2 ) peaks increases with immersion time in the 0.9% NaCl solution. The O 1s spectra are shown in Fig.…”

Section: Resultsmentioning

confidence: 94%

Corrosion products and mechanism on NiTi shape memory alloy in physiological environment

Chu

Xin

et al. 2010

J. Mater. Res.

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Despite many investigations on the corrosion behavior of NiTi shape memory alloys (SMAs) in various simulated physiological solutions by electrochemical measurements, few have reported detailed information on the corrosion products. In the present study, the structure and composition of the corrosion products on NiTi SMAs immersed in a 0.9% NaCl physiological solution are systematically investigated by scanning electron microscopy (SEM), x-ray energy dispersion spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS). It is found that attack by Cl−results in nickel being released into the solution and decrease in the local nickel concentration at the pitting sites. The remaining Ti reacts with dissolved oxygen from the solution to form titanium oxides. After long-term immersion, the corrosion product layer expands over the entire surface and XPS reveals that the layer is composed of TiO2, Ti2O3, and TiO with relatively depleted Ni. The growth rate of the corrosion product layer decreases with immersion time, and the corrosion product layer is believed to impede further corrosion and improve the biocompatibility of NiTi alloy in a physiological environment. It is found that the release rate of nickel is related to the surface structure of the corrosion product layer and immersion time. A corrosion mechanism is proposed to explain the observed results.

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Section: Resultsmentioning

confidence: 94%

Corrosion products and mechanism on NiTi shape memory alloy in physiological environment

Chu

Xin

et al. 2010

J. Mater. Res.

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“…For a given laser pulse duration of 50 fs, the higher laser energies would cause a thermal ablation behavior with obviously molten traces [22] so that many oxide materials can be produced during these processes, as shown in Figures 4 and 5. Since evaporation of Ni and Ti elements would take place during the thermal process, and the evaporation of Ti is faster than that of Ni, together with the different affinity of Ni and Ti for oxygen [16] , Ni/Ti changed greatly when the samples machined under different laser energies.…”

Section: Resultsmentioning

confidence: 99%

“…Although laser spray is a more convenient method to prepare the porous NiTi surface and can OPTICS SPECIAL TOPIC ARTICLES keep the mechanical property of the base [13,14] , this method usually needs TiH 2 as a vesicant which may have a negative effect on the bioactivity of NiTi. Recently Wong et al [16] made an attempt to utilize Nd-YAG lasers to treat the NiTi alloy surface, and found that the oxidization depth increased. However, the porous metal surface was not generated on their expectations.…”

Section: Introductionmentioning

confidence: 99%

Preparation of porous microstructures on NiTi alloy surface with femtosecond laser pulses

et al. 2008

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Porous microstructures on Nickel-Titanium (NiTi) alloy surfaces were prepared by linearly polarized femtosecond lasers with moving focal point at a certain speed. It was found that various novel microstructures from feather-like ripples to cluster-like porous textures could be formed with increasing laser energy. Particularly, when the laser energy was 400 μJ, a periodic porous metal surface was generated. Measurement of X-ray diffraction showed that the grains on the sample surface were refined through femtosecond laser ablation processes, but the crystal structures still kept their original states. Analysis by X-ray photoelectron spectroscopy revealed that Ni/Ti on the sample surface was changed with an evident oxidization of titanium element under different laser energies. This investigation provides a new approach to improve the biocompatibility of NiTi-based implant devices.femtosecond laser, NiTi alloy, porous microstructures, grain refinement

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“…A large fraction of C on the bare NiTi surface stems from surface contamination during mechanical polishing, cleaning in ethanol, or physical and chemical adsorbed CO 2 , and this is consistent with previous observation. 27,28 The atomic fraction of O on the DLC surface is 15.63% because of physical and/or chemical adsorption of O 2 when exposed to air. Liu 29 and Kwok 30 have reported similar results.…”

Section: Sample Characterizationmentioning

confidence: 99%

Biological response of endothelial cells to diamond‐like carbon‐coated NiTi alloy

Hang¹,

Zhang²,

Ma³

et al. 2011

J Biomedical Materials Res

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Diamond-like carbon (DLC) coatings were deposited on nearly equiatomic nickel-titanium (NiTi) alloy by arc-enhanced magnetron sputtering. The microstructure, surface morphology, chemical composition, surface free energy, protein adsorbance, and leach amount of Ni ions were assessed by Raman spectroscopy, high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), contact angle measurements, micro BCA™ protein assay kit, and inductively coupled plasma mass spectrometry (ICP-MS). The biological response of the endothelial cells (ECs) was evaluated by cell adhesion, morphology, viability, and expression levels of thrombogenicity-related genes. Our results show that the DLC coatings inhibit the release of Ni ions from the NiTi substrate effectively thus enhancing its biosafety. The easy adhesion, elongated morphology, and high viability of ECs on the DLC coatings suggest fast endothelialization after implantation and so application of DLC coatings improves the surface properties of NiTi in cardiovascular applications. The relationship between the surface characteristics, Ni leaching, and concomitant biological response are discussed in details.

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Characterization of oxide film formed on NiTi by laser oxidation

Cited by 50 publications

References 33 publications

Corrosion products and mechanism on NiTi shape memory alloy in physiological environment

Corrosion products and mechanism on NiTi shape memory alloy in physiological environment

Preparation of porous microstructures on NiTi alloy surface with femtosecond laser pulses

Biological response of endothelial cells to diamond‐like carbon‐coated NiTi alloy

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