Estimation of titanium oxide layer thickness on thermally oxidized NiTi alloy based on color variations

2022 ◽  
Vol 53 (1) ◽  
pp. 47-55
Author(s):  
C.W. Ng ◽  
A.S. Mahmud ◽  
M.N. Ahmad ◽  
M.F. Razali ◽  
Y. Liu
Keyword(s):  
Oxide Layer ◽  
Layer Thickness ◽  
Titanium Oxide ◽  
Niti Alloy ◽  
Oxide Layer Thickness ◽  
Titanium Oxide Layer

Corrosive behaviour of Amplatzer® devices in experimental and biological environments

2002 ◽  
Vol 12 (3) ◽  
pp. 260-265 ◽  
Author(s):  
Huafu Kong ◽  
James L. Wilkinson ◽  
James Y. Coe ◽  
Xiaoping Gu ◽  
Myra Urness ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxide Layer ◽  
Titanium Oxide ◽  
Saline Solution ◽  
Nickel Titanium ◽  
Cardiac Transplant ◽  
Titanium Oxide Layer ◽  
Device Placement

Purpose: Nitinol, a nickel-titanium alloy, is a valuable material in the construction of interventional endoluminal devices because of its biocompatibility, super elasticity, high resiliency and shape memory. The possibility of nickel toxicity has been raised with devices constructed of Nitinol. Our investigation examines the long-term corrosive behavior of this alloy in experimental and biological environments. Methods: We performed three levels of study. Microscopic examination was made of 64 devices of various sizes, randomly selected from 240 Amplatzer® Septal Occluders that had been exposed to saline solution at 37°C for fourteen months. All samples were studied by electron microscopy ranging from 50 to 5000 times magnification. We also studied microscopically 3 Amplatzer® devices explanted 18–36 months after implantation in dogs, and 2 Amplatzer Septal Occluders removed from patients 18 months (cardiac transplant) and 19 months (died of causes unrelated to device placement) after implantation, which were examined grossly and by electron microscopy up to 5000 times magnification. We then measured the levels of nickel in the blood using inductive plasma mass spectroscopy in 19 patients with implanted Amplatzer® devices, making measurements before and 6 months after implantation. Results: Electron microscopy showed an intact titanium oxide layer with no evidence of corrosion in vitro and in vivo. One explanted device in direct contact with the platinum leads of a pacemaker for eighteen months showed minor pitting of the titanium oxide layer believed to be galvanic in nature. No wire fractures were found in vitro after cycle testing with 400 million cycles, nor in devices taken from the animals and humans. Biochemical studies showed no significant elevation of levels of nickel levels after implantation. Conclusion: Nitinol wire of Amplatzer® septal occlusion devices is resistant to corrosion when exposed to physiologic saline solution, and in experimental animals as well as humans. A device in contact with a platinum pacemaker electrode developed minimal pitting of the titanium oxide layer, believed to be galvanic in nature and of no structural or clinical significance. There is no increase of concentrations of nickel in the blood of patients who have received Amplatzer® nitinol devices. These favorable testing results reveal that nickel-titanium is an inert, corrosion resistant alloy.

Characterization of Inhomogeneity in Thermal Oxide SiO2 Films on 4H-SiC Epitaxial Substrates by a Combination of Fourier Transform Infrared Spectroscopy and Cathodoluminescence Spectroscopy

2018 ◽  
Vol 924 ◽  
pp. 273-276 ◽  
Author(s):  
Masanobu Yoshikawa ◽  
Keiko Inoue ◽  
Junichiro Sameshima ◽  
Hirohumi Seki
Keyword(s):  
Fourier Transform ◽  
Oxide Layer ◽  
Layer Thickness ◽  
Phonon Mode ◽  
Fourier Transform Infrared ◽  
Blue Shift ◽  
Peak Frequency ◽  
Oxide Layer Thickness ◽  
Thermal Oxide ◽  
Ft Ir

We measured Fourier transform infrared (FT-IR) and cathodoluminescence (CL) spectra of SiO2 films with a various thickness, grown on 4H-SiC substrates. The peak frequency of the transverse optical (TO) phonon mode was blue-shifted by about 5 cm−1 as the oxide-layer thickness decreased from 50-60 nm to 10 nm. The blue shift of the TO mode is considerd to be caused by interfacial compressive stresses in the oxide-layer. On the other hand, the TO phonon mode was found to dramatically decrease as the oxide-layer thickness decreased from 10 nm to 1.7 nm. The CL measurement indicates that the intensity of the CL peaks at about 460 and 490 nm attributed to oxygen vacancy centers (OVCs) for No.2 become stronger than that for No.1. From a comparison between FT-IR and CL measurements, we concluded that the red-shift of the TO phonon with decreasing the oxide-layer thickness can mainly be attributed to an increase in inhomogeneity at the SiO2/SiC interface with decreasing oxide-layer thickness.

The possibility to control the thickness of the oxide layer on the titanium Grade 2 by mechanical activation and heat treatment

2020 ◽  
Vol 2 (100) ◽  
pp. 70-77
Author(s):  
M. Szota ◽  
A. Łukaszewicz ◽  
K. Machnik
Keyword(s):  
Heat Treatment ◽  
Mechanical Activation ◽  
Oxide Layer ◽  
Layer Thickness ◽  
Pure Titanium ◽  
Medical Application ◽  
Oxide Layer Thickness ◽  
Surface Development ◽  
Titanium Grade ◽  
Practical Implications

Purpose: The paper presents the results of microstructure, surface development and thickness of the oxide layer on the pure titanium Grade 2 after mechanical activation and heat treatment (550°C/5h). Design/methodology/approach: Studies show that it is possible to control the thickness of the oxide layer by using different materials to change the roughness of surface - mechanical activation before heat treatment. After mechanical activation and heat treatment, the results of the thickness of the oxide layer as well as a level of surface development were obtained, presented and discussed. Findings: The conducted research have proved that mechanical activation of the surface which cause increase of surface development results in greater thickness of oxide layer which is formed during heat treatment. Nevertheless mechanical activation that results in decrease of surface development, such as polishing, results in decrease of oxide layer thickness. Research limitations/implications: The conducted research have showed up that mechanical activation of the surface which cause increase of surface development results in greater thickness of oxide layer which is formed during heat treatment. Nevertheless, mechanical activation that results in decrease of surface development, such as polishing, results in decrease of oxide layer thickness. Practical implications: are possible using similar method for passivation titanium alloys for medical application. Originality/value: The paper presents the possibility of using mechanical preactivation of surface before heat treatment passivation.

Silicon Nanoparticles: Stability in Aqueous Slurries and the Optimization of the Oxide Layer Thickness for Optimal Electrochemical Performance

2017 ◽  
Vol 9 (38) ◽  
pp. 32727-32736 ◽  
Author(s):  
Linghong Zhang ◽  
Yuzi Liu ◽  
Baris Key ◽  
Stephen E. Trask ◽  
Zhenzhen Yang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Oxide Layer ◽  
Layer Thickness ◽  
Silicon Nanoparticles ◽  
Oxide Layer Thickness ◽  
Nanoparticles Stability
Sign in / Sign up

Export Citation Format

Share Document