Highly Biocompatible Porous NiTi Alloys

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.

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Porous NiTi alloys produced by press-and-sinter from Ni/Ti and Ni/TiH2 mixtures

Materials Science and Engineering A ◽

10.1016/j.msea.2013.05.082 ◽

2013 ◽

Vol 582 ◽

pp. 117-125 ◽

Cited By ~ 26

Author(s):

Gang Chen ◽

Peng Cao ◽

Neil Edmonds

Keyword(s):

Niti Alloys ◽

Porous Niti

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Study on Preparation and Anodic Oxidation of Gradient Porous NiTi Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.430-432.1373 ◽

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.

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Fabrication and Surface Modification of Porous Nano-Structured NiTi Orthopedic Scaffolds for Bone Implants

MRS Proceedings ◽

10.1557/proc-1181-dd08-01 ◽

2009 ◽

Vol 1181 ◽

Cited By ~ 1

Author(s):

Shuilin Wu ◽

Xiangmei Liu ◽

Paul K Chu ◽

Tao Hu ◽

Kelvin Wai Kwok Yeung ◽

...

Keyword(s):

Mechanical Properties ◽

Surface Modification ◽

Shape Memory ◽

Porous Ceramics ◽

Bone Implants ◽

Nickel Ion ◽

Niti Alloys ◽

Porous Niti ◽

Surface Areas ◽

Good Shape

AbstractNear-equiatomic porous nickel-titanium shape memory alloys (NiTi SMAs) are becoming one of the most promising biomaterials in bone implants because of their unique advantages over currently used biomaterials. For example, they have good mechanical properties and lower Young�s modulus relative to dense NiTi, Ti, and Ti-based alloys. Porous NiTi SMAs are relatively easy to machine compared to porous ceramics such as hydroxyapatite and calcium phosphate that tend to exhibit brittle failure. The porous structure with interconnecting open pores can also allow tissue in-growth and favors bone osseointegration. In addition, porous NiTi alloys remain exhibiting good shape memory effect (SME) and superelasticity (SE) similar to dense NiTi alloys. To optimize porous NiTi SMAs in bone implant applications, the current research focuses on the fabrication methods and surface modification techniques in order to obtain adjustable bone-like structures with good mechanical properties, excellent superelasticity, as well as bioactive passivation on the entire exposed surface areas to block nickel ion leaching and enhance the surface biological activity. This invited paper describes progress in the fabrication of the porous materials and our recent work on surface nanorization of porous NiTi scaffolds in bone grafts applications.

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Effect of NH4HCO3 Contents on the Microstructure of the Microwave Sintered Porous NiTi Alloys

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.496-500.264 ◽

2014 ◽

Vol 496-500 ◽

pp. 264-267

Author(s):

Ji Lin Xu ◽

Xiao Fei Jin ◽

Jun Ming Luo ◽

Ai Hui Liu

Keyword(s):

Surface Roughness ◽

Pore Size ◽

Optical Microscopy ◽

Microwave Sintering ◽

X Ray Diffraction ◽

X Ray ◽

Niti Alloys ◽

Porous Niti ◽

Diffraction Peaks

In this paper, the porous NiTi alloys were prepared by microwave sintering, and the effects of NH4HCO3contents on the microstructure of the porous NiTi alloys were studied. The microstructure of the porous NiTi alloys was investigated by optical microscopy, Archimedes drainage method, surface roughmeter and X-ray diffraction. The results showed that the porous NiTi alloys were mainly composed of NiTi, Ni3Ti, Ti2Ni and Ni, and the diffraction peaks of the non-equiatomic phases (Ni3Ti, Ti2Ni and Ni) increased with increasing the NH4HCO3contents. At the same time, the porosity, pore size and surface roughness of the porous NiTi alloys increased with the increase of the NH4HCO3contents.

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