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.

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.

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 on Effect of Sintering Temperature on Microstructure and Compressive Property of Porous NiTi Alloys

2011 ◽  
Vol 299-300 ◽  
pp. 480-483 ◽  
Author(s):  
Jing Yuan Yu ◽  
Qiang Li
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Sintering Temperature ◽  
Testing Machine ◽  
Compressive Property ◽  
Powder Metallurgy Method ◽  
Niti Alloys ◽  
Porous Niti ◽  
Universal Testing ◽  
Niti Phase

Porous NiTi alloys were prepared by powder metallurgy method using NH4HCO3as space-holder. The effect of sintering temperature on pore characteristic, phase composition and compressive property of porous NiTi alloys was studied by XRD, SEM, EDS and a universal testing machine. The results show with the increase of sintering temperature the porosity of porous NiTi alloys first increases and then decreases, but the content of NiTi phase, compressive strength and modulous of sintered products continuously increase. When sintered at 980°C for 2h, the porous NiTi alloys have higher porosity of 53.6%, better compressive strength of 173.7MPa and elastic modulous of 4.2GPa. The phases of sinter products are mainly composed by TiNi, Ti2Ni, and TiNi3phases.

Porous NiTi alloy by metal injection moulding/sintering of elemental powders: Effect of sintering temperature

2012 ◽  
Vol 70 ◽  
pp. 142-145 ◽  
Author(s):  
Muhammad Hussain Ismail ◽  
Russell Goodall ◽  
Hywel A. Davies ◽  
Iain Todd
Keyword(s):  
Injection Moulding ◽  
Sintering Temperature ◽  
Niti Alloy ◽  
Porous Niti ◽  
Metal Injection Moulding

A Comparison Between Porous NiTi and Ti-6Al-4V Fixation Hardware on Bone Remodeling After a Reconstruction Surgery

2016 ◽  
Author(s):  
Bahram Raad ◽  
Narges Shayesteh Moghaddam ◽  
Mohammad Elahinia
Keyword(s):  
Density Distribution ◽  
Bone Remodeling ◽  
Niti Alloy ◽  
Healing Process ◽  
Stress Shielding ◽  
Element Model ◽  
Reconstruction Surgery ◽  
Porous Niti ◽  
Surrounding Bone ◽  
The Finite Element Model

The aim of this article is to investigate the effect of two different fixation hardware materials on bone remodeling after a mandibular reconstruction surgery and to restore the mandible’s function, healthy appearance, mastication, swallowing, breathing, and speech. The hypothesis is that using fixation hardware with stiffness close to that of the surrounding bone will result in a more successful healing process in the mandible bone. The finite element model includes the material properties and forces of the cancellous bone, cortical bone, ligaments, muscles, and teeth. The reconstruction surgery is modeled by including the fixation hardware and the grafted bone. In the sectioned mandible, to best mimic the geometry of the mandible, two single barrel grafts are placed at the top of each other to form a double barrel graft set. Two different materials were used as the mandibular fixation parts, stiff Ti-6Al-4V, and porous superelastic Nickel-Titanium (NiTi) alloys. A comparison of these two alloys demonstrates that using porous NiTi alloy as the fixation part results in a faster healing pace. Furthermore, the density distribution in the mandibular bone after the healing process is more similar to the normal mandible density distribution. The simulations results indicate that the porous superelastic NiTi fixation hardware transfers and distributes the existing forces on the mandible bone more favorably. The probability of stress shielding and/or stress concentration decrease. This type of fixation hardware, therefore, is more appropriate for mandible bone reconstruction surgery.

An investigation on the possibility to improve the corrosion and cavitation resistance of SS304 steel by NiTi coatings

2021 ◽  
Vol 35 (04) ◽  
pp. 2150057
Author(s):  
Qunfeng Zeng ◽  
Khashayar Khanlari ◽  
Naiming Lin
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Niti Alloy ◽  
Preliminary Investigation ◽  
Industrial Applications ◽  
Cavitation Resistance ◽  
Niti Alloys ◽  
Materials Used ◽  
Ss 304 ◽  
Increasing Load

Equiatomic and near equiatomic NiTi alloys, showing good mechanical and thermal shape memory properties, are widely exploited in different industrial applications. In addition, NiTi alloys have promising anti-cavitation and corrosion-resistance properties. These advantages have provided opportunities to exploit NiTi alloys as the coatings for protecting materials used in the industrial applications. This study is a preliminary investigation aiming to evaluate the feasibility to form NiTi alloy coatings on SS304 steel by tungsten inert argon arc welding (TIG) technology. The microstructure analysis shows that the crystalline phases in NiTi coatings on SS 304 steel are TiNi-B2, TiNi-B19’ and Ni3Ti. The potential of the NiTi coatings to enhance the corrosion resistance and cavitation resistance behaviors of steel exposed to seawater is studied. NiTi coatings, with two different thicknesses of about 1.2 and 2 mm, having homogenous microstructures were successfully deposited on SS304 steel using TIG technology. Results of tests, done in aqueous solutions simulating seawater, showed that the formation of the oxide films on the surface of NiTi coatings increased the corrosion resistance and wear resistance and decreased the damage caused by the cavitation. Moreover, it was understood that the NiTi coatings with 2 mm in thickness show the superior performances than those with 1.2 mm in thickness. The tribological mechanisms responsible for the unique properties of NiTi alloy coatings were investigated. The wear-resistance behaviors of NiTi alloy coatings are greatly influenced by the friction conditions. Increasing load decreased CoF and the wear rate of the coatings were almost constant, which was attributed to the pseudoelasticity of NiTi alloy. The attractive properties of NiTi alloys that makes it most influential materials for industrial applications have also been discussed.

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.

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
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