Corrosion Kinetics of Laser Treated NiTi Shape Memory Alloy Biomaterials

1996 ◽  
Vol 459 ◽  
Author(s):  
F. Villermaux ◽  
I. Nakatsugawa ◽  
M. Tabrizian ◽  
D. L. Piron ◽  
M. Meunier ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Laser Treatment ◽  
Niti Alloy ◽  
Niti Shape Memory Alloy ◽  
Surgical Implants ◽  
Hank’S Solution ◽  
Kinetics Of ◽  
Human Fluids

ABSTRACTNiTi shape memory alloy presents interesting mechanical properties as surgical implants. However, due to its high amount of Ni which may dissolve and release toxic ions in human fluids, the medical use of this material is a great concern. We have developed a laser treatment which modifies the oxide layer and enhances uniform and localised corrosion resistance of NiTi alloy.In this paper we further analysed the effect of this treatment with potentiostatic and AC impedance measurements in physiological Hank's solution. We conclude that the laser treatment creates a stable passive film which results in improved corrosion resistance of this alloy.

Application of EIS to Study the Corrosion Resistance of Passivated NiTi Shape Memory Alloy in Simulated Body Fluid

2011 ◽  
Vol 183 ◽  
pp. 57-64 ◽  
Author(s):  
Marlena Freitag ◽  
B. Łosiewicz ◽  
Tomasz Goryczka ◽  
Józef Lelątko
Keyword(s):  
Corrosion Resistance ◽  
Shape Memory Alloy ◽  
Simulated Body Fluid ◽  
Shape Memory ◽  
Pitting Corrosion ◽  
Body Fluid ◽  
Niti Alloy ◽  
Amorphous State ◽  
Open Circuit ◽  
Niti Shape Memory Alloy

The NiTi shape memory alloy passivated for 90 min by autoclaving has been studied towards corrosion performance in the Tyrode’s simulated body fluid using open circuit potential and EIS measurements. The surface morphology and thickness of the oxide layer was determined by XRR. The HREM was used to observe the cross-section of the thin foil and to confirm the amorphous state of the TiO2 layer and its thickness. Electrochemical measurements revealed a good corrosion resistance at the beginning of long-term (20 days) immersion. It was found that with the increase of immersion time, the corrosion resistance of the surface deteriorated after nearly 1 day of immersion due to occurence of pitting corrosion. The EIS method was used to detailed study on the electrolyte | passive layer interfacial properties. Equivalent electrical circuit for the pitting corrosion on the passivated NiTi alloy has been applied.

Effects of Anodic Oxidation in Ethylene Glycol Based Electrolyte on the Corrosion Resistance and Biocompatibility of NiTi Shape Memory Alloy

2013 ◽  
Vol 829 ◽  
pp. 431-435 ◽  
Author(s):  
Maryam Pourmahdavi ◽  
Nader Parvin
Keyword(s):  
Corrosion Resistance ◽  
Shape Memory Alloy ◽  
Ethylene Glycol ◽  
Shape Memory ◽  
Niti Alloy ◽  
Medical Application ◽  
Electrochemical Anodization ◽  
Niti Shape Memory Alloy ◽  
Nanoporous Surface ◽  
Glycol Solution

Nickel titanium (NiTi) is the most attractive shape memory alloy in industrial and in medical application but suffer from corrosion attack by body fluids. Nowadays, Electrochemical anodization has become a popular surface modification method for biomaterials. In this study we prepared TiO2 coating with nanoporous surface morphology on NiTi shape memory alloy by using electrochemical anodization in ethylene glycol based electrolyte followed by annealing in 600 °C and explored its appropriateness for biomedical applications. Morphology and crystal structure of the film was characterized by Field emission scanning electron microscopiy (FE-SEM) and X-ray diffraction (XRD) tests. The corrosion resistance of the treated NiTi alloy was investigated by potentiodynamic polarization test and The findings showed that the anodization in ethylene glycol solution extremely increased the corrosion resistance and hence biocompatibility.

scholarly journals Key Properties of a Bioactive Ag-SiO2/TiO2 Coating on NiTi Shape Memory Alloy as Necessary at the Development of a New Class of Biomedical Materials

2021 ◽  
Vol 22 (2) ◽  
pp. 507
Author(s):  
Mateusz Dulski ◽  
Robert Gawecki ◽  
Sławomir Sułowicz ◽  
Michal Cichomski ◽  
Alicja Kazek-Kęsik ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Dermal Fibroblast ◽  
Niti Alloy ◽  
Bacterial Biofilm ◽  
Niti Shape Memory Alloy ◽  
Normal Human Dermal Fibroblast ◽  
Water Contact ◽  
Nano Coating

Recent years have seen the dynamic development of methods for functionalizing the surface of implants using biomaterials that can mimic the physical and mechanical nature of native tissue, prevent the formation of bacterial biofilm, promote osteoconduction, and have the ability to sustain cell proliferation. One of the concepts for achieving this goal, which is presented in this work, is to functionalize the surface of NiTi shape memory alloy by an atypical glass-like nanocomposite that consists of SiO2-TiO2 with silver nanoparticles. However, determining the potential medical uses of bio(nano)coating prepared in this way requires an analysis of its surface roughness, tribology, or wettability, especially in the context of the commonly used reference coat-forming hydroxyapatite (HAp). According to our results, the surface roughness ranged between (112 ± 3) nm (Ag-SiO2)—(141 ± 5) nm (HAp), the water contact angle was in the range (74.8 ± 1.6)° (Ag-SiO2)—(70.6 ± 1.2)° (HAp), while the surface free energy was in the range of 45.4 mJ/m2 (Ag-SiO2)—46.8 mJ/m2 (HAp). The adhesive force and friction coefficient were determined to be 1.04 (Ag-SiO2)—1.14 (HAp) and 0.247 ± 0.012 (Ag-SiO2) and 0.397 ± 0.034 (HAp), respectively. The chemical data showed that the release of the metal, mainly Ni from the covered NiTi substrate or Ag from Ag-SiO2 coating had a negligible effect. It was revealed that the NiTi alloy that was coated with Ag-SiO2 did not favor the formation of E. coli or S. aureus biofilm compared to the HAp-coated alloy. Moreover, both approaches to surface functionalization indicated good viability of the normal human dermal fibroblast and osteoblast cells and confirmed the high osteoconductive features of the biomaterial. The similarities of both types of coat-forming materials indicate an excellent potential of the silver-silica composite as a new material for the functionalization of the surface of a biomaterial and the development of a new type of functionalized implants.

EFFECTS OF PARTICLE SIZE AND SINTERING TEMPERATURE ON SUPERELASTICITY BEHAVIOR OF NiTi SHAPE MEMORY ALLOY USING NANOINDENTATION

2021 ◽  
pp. 2150024
Author(s):  
C. VELMURUGAN ◽  
V. SENTHILKUMAR
Keyword(s):  
Particle Size ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Sintering Temperature ◽  
Niti Alloy ◽  
Indentation Load ◽  
Niti Shape Memory Alloy ◽  
Recovery Ratio ◽  
Work Recovery ◽  
Niti Sma

The present study investigates the superelasticity properties of spark plasma sintered (SPS) nickel titanium shape memory alloy (NiTi SMA) with the influence of sintering temperature and particle size. The nanoindentation is conducted on the surface of the NiTi SMA at various loads such as 100, 300 and 500[Formula: see text]mN. The nanoindentation technique determines the quantitative results of elasto-plastic properties such as depth recovery in the form of superelasticity, stiffness, hardness and work recovery ratio from load–depth ([Formula: see text]–[Formula: see text]) data during loading and unloading of the indenter. Experimental findings show that the depth and work recovery ratio increases with the decrease of indentation load and particle size. In contrast, increasing the sintering temperature exhibited a better depth and work recovery due to the removal of pores which could enhance the reverse transformation. The contact stiffness is influenced by [Formula: see text] which leads to attain a maximum stiffness at the highest load (500[Formula: see text]mN) and particle size (45[Formula: see text][Formula: see text]m) along with the lowest sintering temperature (700∘C). NiTi alloy exhibited a maximum hardness of 9.46[Formula: see text]GPa when subjected to indent at the lowest load and particle size sintered at 800∘C. The present study reveals a better superelastic behavior in NiTi SMA by reducing the particle size and indentation load associated with the enhancement of sintering temperature.

scholarly journals Experimental Analysis of NiTi Alloy during Strain-Controlled Low-Cycle Fatigue

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4455
Author(s):  
Pedro Cunha Lima ◽  
Patrícia Freitas Rodrigues ◽  
Ana Sofia Ramos ◽  
José D. M. da Costa ◽  
Francisco Manuel Braz Fernandes ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Low Cycle Fatigue ◽  
Niti Alloy ◽  
Niti Shape Memory Alloy ◽  
Cycle Fatigue ◽  
Maximum Deformation ◽  
Transmission Electron ◽  
Before And After

The interaction between the stress-induced martensitic transformation and resistivity behavior of superelastic NiTi shape memory alloy (SMA) was studied. Strain-controlled low-cycle fatigue up to 6% was monitored by in situ electrical resistivity measurements. The experimental results show that a great motion of martensite fronts results in a significant accumulation of defects, as evidenced by transmission electron microscopy (TEM), before and after the tensile cycles. This gives rise to an overall increase of the resistivity values up to the maximum deformation. Therefore, the research suggests that shape memory alloy wire has great potential as a stress sensor inside bulk materials.

scholarly journals Functional Behavior of Pseudoelastic NiTi Alloy Under Variable Amplitude Loading

2020 ◽  
Vol 14 (3) ◽  
pp. 154-160
Author(s):  
Volodymyr Iasnii ◽  
Petro Yasniy ◽  
Yuri Lapusta ◽  
Oleg Yasniy ◽  
Oleksandr Dyvdyk
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Residual Strain ◽  
Niti Alloy ◽  
Strain Curve ◽  
Niti Shape Memory Alloy ◽  
Dissipation Energy ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Lower Amplitude

Abstract Cyclic loading of superelastic NiTi shape memory alloy (SMA) causes forward and reverse austenite–martensіte transformations, and also increases the volume of stabilized martensite. This appears in the change of stress-strain curve form, the decrease of dissipation energy, and increase of residual strain, that is, named transformation ratcheting. In real structures, the SMA components in most cases are under the action of variable amplitude loading. Therefore, it is obvious that the loading history will influence the functional fatigue. In the present work, the effect of stress ratio on the functional properties of superelastic NiTi shape memory alloy under variable amplitude loading sequence with two blocks was investigated. The studies were carried out under the uniaxial tension of cylindrical specimens under load-full unload and load-part unload. The change of residual strain, strain range, dissipation, and cumulative dissipation energy density of NiTi alloy related to load sequences are discussed. Under both stress ratios, the residual strain in NiTi alloy is increased depending on the number of loading cycles on the high loading block that is similar to the tests at constant stress or strain amplitude. An unusual effect of NiTi alloy residual strain reduction with the number cycles is found at a lower block loading. There was revealed the effect of residual strain reduction of NiTi alloy on the number of loading cycles on the lower amplitude block. The amount of decrement of the residual strain during a low loading block is approximately equal to the reversible part of the residual strain due to the stabilized martensite. The decrease of the residual strain during the low loading block is approximately equal to the reversible part of residual strain due to the stabilized martensite. A good correlation of the effective Young’s modulus for both load blocks with residual strain, which is a measure of the volume of irreversible martensite, is observed.

Damping Characteristics of Biomedical Porous NiTi Shape Memory Alloy

2010 ◽  
Vol 97-101 ◽  
pp. 1083-1086
Author(s):  
Hai Chang Jiang ◽  
Shu Wei Liu ◽  
Xiu Yan Li ◽  
Li Jian Rong
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Strain Amplitude ◽  
Niti Alloy ◽  
Small Strain ◽  
Cooling Curve ◽  
Niti Shape Memory Alloy ◽  
Internal Friction Peak ◽  
Porous Niti ◽  
Tan Δ

One internal friction peak associated with the B2↔B19’ transformation appears on the cooling curve of porous NiTi shape memory alloy and the dense NiTi alloy shows the maximum peak. The tan δ value increased with the increasing of strain amplitude and the decreasing of frequency. Tan δ value of porous alloy mainly comes from the energy absorbing of the matrix at the small strain amplitude, however, if the strain amplitude is large, the tan δ value comes from the energy consumption that overcomes the friction between folds and the plastic contribution.

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