Study on Surface Oxidation Behavior of Pourous NiTi Alloy at High Temperature

2011 ◽  
Vol 299-300 ◽  
pp. 534-537
Author(s):  
Qiang Li ◽  
Xiao Na Zhang
Keyword(s):  
High Temperature ◽  
Body Fluid ◽  
Niti Alloy ◽  
Surface Oxidation ◽  
Powder Metallurgy Method ◽  
Ion Release ◽  
Oxidation Layer ◽  
Porous Niti ◽  
Before And After

In this paper, porous NiTi alloy prepared by powder metallurgy method was oxidized at high temperature. The effect of oxidation temperature and time on quality of oxidation layer of porous NiTi was studied. The component and morphology of oxidation layer before and after oxidation at high temperature were analyzed by XPS and SEM. The behavior of Ni ion release of porous NiTi alloy was observed. The results showed uniform and thick oxidation layer was formed on the surface of porous NiTi alloy after oxidation at 550°C for 1h. XPS analysis showed the oxidation layer mainly composed of TiO2, and the thickness of the film was about 180nm higher than that before oxidation. The research on the behavior of Ni ion release showed the Ni release after oxidation can be significantly reduced at simulated body fluid due to TiO2layer.

STUDY OF NICKEL ION RELEASE IN SIMULATED BODY FLUID FROM C+-IMPLANTED NICKEL TITANIUM ALLOY

2016 ◽  
Vol 23 (05) ◽  
pp. 1650045 ◽  
Author(s):  
MUHAMMAD AHSAN SHAFIQUE ◽  
G. MURTAZA ◽  
SHAHZAD SAADAT ◽  
ZEESHAN ZAHEER ◽  
MUHAMMAD SHAHNAWAZ ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Niti Alloy ◽  
Niti Shape Memory Alloy ◽  
Ion Release ◽  
Nickel Ion ◽  
Oxidation Layer ◽  
X Ray ◽  
Calcium Phosphate Precipitation

Nickel ion release from NiTi shape memory alloy is an issue for biomedical applications. This study was planned to study the effect of C[Formula: see text] implantation on nickel ion release and affinity of calcium phosphate precipitation on NiTi alloy. Four annealed samples are chosen for the present study; three samples with oxidation layer and the fourth without oxidation layer. X-ray diffraction (XRD) spectra reveal amorphization with ion implantation. Proton-induced X-ray emission (PIXE) result shows insignificant increase in Ni release in simulated body fluid (SBF) and calcium phosphate precipitation up to [Formula: see text][Formula: see text]ions/cm2. Then Nickel contents show a sharp increase for greater ion doses. Corrosion potential decreases by increasing the dose but all the samples passivate after the same interval of time and at the same level of [Formula: see text] in ringer lactate solution. Hardness of samples initially increases at greater rate (up to [Formula: see text][Formula: see text]ions/cm[Formula: see text] and then increases with lesser rate. It is found that [Formula: see text][Formula: see text]ions/cm2 ([Formula: see text] is a safer limit of implantation on NiTi alloy, this limit gives us lesser ion release, better hardness and reasonable hydroxyapatite incubation affinity.

Study on Preparation and Anodic Oxidation of Gradient Porous NiTi Alloy

2012 ◽  
Vol 430-432 ◽  
pp. 1373-1377
Author(s):  
Qiang Li ◽  
Jing Yuan Yu ◽  
Xu Dong Sun
Keyword(s):  
Anodic Oxidation ◽  
Niti Alloy ◽  
Surface Film ◽  
Powder Metallurgy Method ◽  
Release Behavior ◽  
Ion Release ◽  
Gradient Distribution ◽  
Niti Alloys ◽  
Porous Niti ◽  
Oxidation Technology

Gradient porous NiTi alloys were prepared by powder metallurgy method using NH4HCO3 as space-holder and modified by direct current-pulse anodic oxidation technology in low temperature. Pore characteristic and phase composition of gradient porous NiTi alloys were studied. Microstructure, composition, anti-corrosion and Ni ion release behavior of surface film were observed. The results show the porosity of porous NiTi alloys decreases from 53.2% to 42.8%, when the content of NH4HCO3 varying from uniformity to gradient distribution. The sintered gradient porous NiTi alloys composes with TiNi, Ti2Ni and TiNi3 phases. After anodic oxidation, Ti oxidation film with the thick of 240nm was formed on the gradient porous NiTi alloy. The corrosion resistance of gradient porous NiTi alloy was obviously improved and the rate of Ni release was significantly reduced.

scholarly journals Novel Multilayer SAW Temperature Sensor for Ultra-High Temperature Environments

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 643
Author(s):  
Xuhang Zhou ◽  
Qiulin Tan ◽  
Xiaorui Liang ◽  
Baimao Lin ◽  
Tao Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Sensor ◽  
X Ray Diffraction ◽  
Aero Engine ◽  
Before And After ◽  
Application Potential ◽  
Passive Sensors ◽  
Temperature Exposure ◽  
Engine Systems

Performing high-temperature measurements on the rotating parts of aero-engine systems requires wireless passive sensors. Surface acoustic wave (SAW) sensors can measure high temperatures wirelessly, making them ideal for extreme situations where wired sensors are not applicable. This study reports a new SAW temperature sensor based on a langasite (LGS) substrate that can perform measurements in environments with temperatures as high as 1300 °C. The Pt electrode and LGS substrate were protected by an AlN passivation layer deposited via a pulsed laser, thereby improving the crystallization quality of the Pt film, with the function and stability of the SAW device guaranteed at 1100 °C. The linear relationship between the resonant frequency and temperature is verified by various high-temperature radio-frequency (RF) tests. Changes in sample microstructure before and after high-temperature exposure are analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis confirms that the proposed AlN/Pt/Cr thin-film electrode has great application potential in high-temperature SAW sensors.

The influence of porosity on corrosion characteristics of porous NiTi alloy in simulated body fluid

2002 ◽  
Vol 57 (2) ◽  
pp. 448-451 ◽  
Author(s):  
Yong-Hua Li ◽  
Guang-Bin Rao ◽  
Li-Jian Rong ◽  
Yi-Yi Li
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Niti Alloy ◽  
Porous Niti

Improvement of the Crystalline Quality of β-Ga2O3 Films by High-Temperature Annealing

2012 ◽  
Vol 725 ◽  
pp. 273-276
Author(s):  
Motoki Takahara ◽  
Suguru Funasaki ◽  
Jyun Kudou ◽  
Isao Tsunoda ◽  
Kenichiro Takakura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Crystalline Quality ◽  
High Temperature Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Si Doped ◽  
Scanning Electron

For the purpose of improving the crystalline quality of undoped and Si doped β-Ga2O3 films, high temperature annealing at 900°C was performed. The crystalline quality of the films investigated using scanning electron microscopy and X-ray diffraction. Also the conductivity of the films is compared before and after the annealing. After the 900°C annealing, the XRD peaks intensity corresponding to β-Ga2O3 is increased. This result indicates that the crystalline quality improves by the high temperature annealing.

Study on Preparation of Gradient Porous NiTi Alloys by Powder Metallurgy Method

2011 ◽  
Vol 299-300 ◽  
pp. 671-674
Author(s):  
Qiang Li ◽  
Jing Yuan Yu ◽  
Guo Chao Qi
Keyword(s):  
Phase Composition ◽  
Elastic Modulus ◽  
Powder Metallurgy ◽  
Porous Materials ◽  
Niti Alloy ◽  
Powder Metallurgy Method ◽  
Compressive Properties ◽  
Niti Alloys ◽  
Porous Niti ◽  
Tini Phase

Gradient porous NiTi alloys were fabricated by powder metallurgy method using NH4HCO3as space-holder. The effect of content and distribution of NH4HCO3on pore characteristic, phase composition and compressive properties was studied. The results showed the content of TiNi phase increased with the decrease of the content of NH4HCO3. When the distribution of NH4HCO3varying form 12wt%-12wt%-12wt% to 12wt%-6wt%-12wt% and 12wt%-0wt%-12wt%, the stress and elastic modulus of porous NiTi alloys increased from 228MPa to 321MP and 446MPa, from 4.8GPa to 5.6GPa and 6.8GPa, respectively. Compared with uniform porous materials, gradient porous NiTi alloy exhibited better superelasticity.

Characterization of bioactive surface oxidation layer on NiTi alloy

2005 ◽  
Vol 252 (5) ◽  
pp. 2038-2049 ◽  
Author(s):  
Y.W. Gu ◽  
B.Y. Tay ◽  
C.S. Lim ◽  
M.S. Yong
Keyword(s):  
Niti Alloy ◽  
Surface Oxidation ◽  
Oxidation Layer

Effect of pores on corrosion characteristics of porous NiTi alloy in simulated body fluid

2003 ◽  
Vol 363 (1-2) ◽  
pp. 356-359 ◽  
Author(s):  
Yong-Hua Li ◽  
Guang-Bin Rao ◽  
Li-Jian Rong ◽  
Yi-Yi Li ◽  
Wei Ke
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Niti Alloy ◽  
Porous Niti

Synthesis of an Oxidation Resistant Coating for Ni-Based High Temperature Structural Materials by Dip Coating

2012 ◽  
Vol 187 ◽  
pp. 251-254
Author(s):  
Wan Ting Chen ◽  
Rudder T. Wu ◽  
Karen Chien ◽  
Liberty T. Wu ◽  
Hong Gao ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Oxidation ◽  
Structural Materials ◽  
Dip Coating ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Cross Sectional ◽  
Before And After ◽  
Scientists And Engineers

High temperature structural materials are becoming increasingly important under the growing demand for stronger materials to work under the aggressive operating conditions of modern gas turbine engines. Alongside the mechanical strength, surface protectiveness of these materials is also of great importance in order to maintain the originally designed microstructure and chemistry. For coating scientists and engineers, a simple and effective method of making surface oxidation- and corrosion- resistant is always preferred. In this study, oxidation resistance of a coating system prepared by means of dip coating is investigated. Cross-sectional morphologies of the dip coated specimens before and after thermal cycling are also characterized using a scanning electron microscope.

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