Fabrication of an Apatite/Collagen Composite Coating on the NiTi Shape Memory Alloy through Electrochemical Deposition and Coating Characterisation

2009 ◽  
Vol 618-619 ◽  
pp. 319-323 ◽  
Author(s):  
Parama Chakraborty Banerjee ◽  
Tao Sun ◽  
Jonathan H.W. Wong ◽  
Min Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Coating ◽  
Electrochemical Deposition ◽  
Room Temperature ◽  
Composite Coatings ◽  
Deposition Process ◽  
Niti Shape Memory Alloy ◽  
X Ray ◽  
Niti Sma

To improve the biocompatibility and bioactivity of NiTi shape memory alloy (SMA), apatite/collagen composite coatings were fabricated on the surface of NiTi SMA at room temperature using the electrochemical deposition technique. Spherical apatite particles and fibrous collagen that formed the composite coating were visible under scanning electron microscope (SEM). The Ca/P ratio of the apatite component in the coating, as determined by energy dispersive X-ray spectroscopy (EDX), was about 1.38 which is slightly higher than that of octocalcium phosphate (OCP). X-ray diffraction result showed that the apatite was amorphous, which was due to the low temperature (i.e., room temperature) deposition process. The structure of the composite coatings was further characterized using Fourier transform infrared reflection spectroscopy (FTIR). It was also found that, compared to bare NiTi SMA samples, the wettability of as-deposited samples was increased because of the formation of the composite coating.

Electrochemical Deposition of Apatite/Collagen Composite Coating on NiTi Shape Memory Alloy and Coating Properties

2009 ◽  
Vol 1239 ◽  
Author(s):  
Min Wang ◽  
Tao Sun
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Coating ◽  
Electrochemical Deposition ◽  
Composite Coatings ◽  
Surface Characteristics ◽  
Corrosion Current ◽  
Niti Shape Memory Alloy ◽  
Niti Sma ◽  
Transmission Electron

AbstractIn this investigation, an apatite/collagen composite coating was formed at 37C on a NiTi shape memory alloy (SMA) through electrochemical deposition using double-strength simulated body fluid (2SBF) which contained dissolved collagen. Surface characteristics, wettability and stability of the composite coating were subsequently studied. Scanning electron microscope (SEM) examination of the surface of composite coatings revealed that many collagen fibers were embedded in apatite with flake-like structure and apatite nanocrystals nucleated and grew on collagen fibrils. Energy dispersive X-ray (EDX) spectroscopy analysis showed that the Ca : P ratio of the composite coating was about 1.35, which is close to that of octocalcium phosphate. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) analysis were also conducted for the composite coating. Compared to bare NiTi SMA samples, the potentiodynamic polarization curves of NiTi SMA samples with the composite coating displayed lower corrosion current density, more positive corrosion and breakdown potential, suggesting that the composite coating was chemically stable and provided corrosion resistance for NiTi SMA.

Characterization of Anatase Coatings on NiTi Shape Memory Alloy by Plasma Electrolytic Oxidation Method

2011 ◽  
Vol 121-126 ◽  
pp. 3837-3841
Author(s):  
Li Hong Lu ◽  
Jing Wu Zhang ◽  
De Jiu Shen
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Plasma Electrolytic Oxidation ◽  
Niti Shape Memory Alloy ◽  
Aqua Regia ◽  
X Ray ◽  
Niti Sma ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Peo Coatings

The anatase coatings was obtained by aqua regia dealloying and plasma electrolytic oxidation (PEO) method on NiTi shape memory alloy (SMA) substrate. The PEO manufacturability of NiTi SMA before and after dealloying was researched. The PEO surface morphologies of the aqua regia treated and untreated specimens were investigated with scanning electron microscopy (SEM). The composition of the PEO coatings was investigated with X-ray diffraction (XRD). The element concentration of the surface of the PEO-treated NiTi SMA was measured by an energy dispersive X-ray spectrometer (EDS). The results indicate that the pre-treatment technology by aqua regia dealloying can greatly improve the PEO manufacturability and the PEO morphologies of the NiTi SMA. The optimum dealloying parameters are at room temperature for 10 min. At this circumstance, the PEO manufacturability of the treated samples is most close to that of the industrial pure titanium. There are many honeycomb-like micro-pores in the surface of the PEO coatings, which act as discharging channels. The cracks are invisible in the SEM images of the PEO coatings. The PEO coatings formed on the NiTi is composed of Ti, Ni, Al, O, Au and P. The composition of the PEO coatings is mainly composed of NiTi phase and anatase phase.

Fabrication of (Ti-O-N-Si)/Ti Composite Coating on NiTi Shape Memory Alloy Using PIIID and Coating Evaluation

2009 ◽  
Vol 1239 ◽  
Author(s):  
Tao Sun ◽  
Langping Wang ◽  
Min Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Coating ◽  
Rf Magnetron Sputtering ◽  
Niti Shape Memory Alloy ◽  
Coating Process ◽  
Niti Sma ◽  
Ni Content ◽  
Coating Formation ◽  
Plasma Immersion Ion Implantation

AbstractA compact and uniform (Ti, Si, O, N)/Ti composite coating was fabricated on the surface of a NiTi shape memory alloy (SMA) (containing 50.8 at.% Ni) using plasma immersion ion implantation and deposition (PIIID) with radio-frequency (RF) magnetron sputtering. The coating and coated NiTi SMA were studied using various techniques. Analysis showed that the Ni content was drastically reduced on the surface of coated samples due to coating formation. This could greatly improve the biocompatibility of NiTi SMA. There was no TiO2 or TiN formation in the coating. The shape memory ability of NiTi SMA samples was no deteriorated by the coating process. The coating significantly improved the corrosion resistance and wear resistance of NiTi SMA and also rendered the material bioactive.

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.

Morphology and I-V Characteristics of Electrochemically Deposited Zinc Oxide on Silicon

2021 ◽  
Vol 20 (3) ◽  
pp. 32-36
Author(s):  
Ahmad Bukhairi Md Rashid ◽  
Mastura Shafinaz Zainal Abidin ◽  
Shaharin Fadzli Abd Rahman ◽  
Amirjan Nawabjan
Keyword(s):  
Zinc Oxide ◽  
Electrochemical Deposition ◽  
Dark Current ◽  
Room Temperature ◽  
Volume Ratio ◽  
Deposition Process ◽  
X Ray ◽  
Current Voltage ◽  
Electrochemically Deposited ◽  
A Current

This paper reported on the electrochemical deposition of zinc oxide (ZnO) on p-silicon (p-Si) (100) substrate in the mixture of 0.1 M of zinc chloride (ZnCl2) and potassium chloride (KCl) electrolyte at a volume ratio of 1:1, 3:1 and 5:1 namely Sample A, B and C. The deposition process was done in room temperature with a current density of 10 mA/cm2 for 30 minutes. Prior to the experiment, all samples were treated by RCA cleaning steps. All samples were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The results show that all samples have the same morphology of a flake-like structure with different Zn:O ratio that were 2.81, 2.35 and 2.49 for samples A, B and C. The current-voltage (I-V) characteristic graph was obtained by dark current measurement using Keithley SMU 2400 and the threshold voltage (Vth) values were determined at 2.21 V, 0.85 V and 1.22 V for sample A, B and C respectively which correspond with the Zn:O ratio where the highest value of Zn:O ratio can be found in sample A and the lowest in sample B. Based on these results, it shows that electrochemical deposition technique is capable of being used to deposit the flake-like structure ZnO on semiconductor material to form the p-n junction which behaves like a diode. The value of Vth seems to be depended on the ratio between Zn and O. Higher ratio of Zn and O will cause the higher value of intrinsic carrier concentration and built in potential which will increase the Vth value.

NiTi Shape Memory Alloy Used for Multiple-Resetting Actuator for Fire Protection

2017 ◽  
Vol 907 ◽  
pp. 8-13 ◽  
Author(s):  
Lucian Burlacu ◽  
Nicanor Cimpoeşu ◽  
Nicoleta Monica Lohan ◽  
Leandru Gheorghe Bujoreanu
Keyword(s):  
Thermal Analysis ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Fire Protection ◽  
Room Temperature ◽  
Parent Phase ◽  
Niti Shape Memory Alloy ◽  
Scanning Calorimetry ◽  
Protection Systems ◽  
Executive Elements

The paper introduces the possibility to replace the “wet alloy”, used for sprinkler-triggering within automatic fire protection systems, with a shape memory alloy (SMA) type. The idea of the present application is based on the thermoelastic reversible martensitic transformation, governing SMA functioning, which has completely reversible character, and enables the occurrence of two-way shape memory effect (TWSME) after the application of a thermomechanical treatment called “training”. For this purpose a commercial NiTi rod, which was martensitic at room temperature, was subjected to thermal analysis tests, performed by differential scanning calorimetry (DSC) and dilatometry. Martensite (M) reversion to parent phase (A), during heating, was emphasized by an endothermic peak on the DSC thermogram and by a length shrinkage, on the dilatogram. The capacity to develop TWSME was revealed by the change in displacement-temperature variation, with increasing the number of training cycles. This stabilized fully reversible behavior recommends NiTi rods as executive elements of a new concept of resettable sprinkler for fire protection.

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