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Electrochemical behavior of Ni-Ti alloy after surface modification  [PDF]
M. Kaczmarek,W. Simka,A. Baron,J. Szewczenko
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: The shape memory effect and superelasticity make the nickel-titanium alloy an interesting material formedical applications. But the biocompatibility has been questioned due to conflicting results in the literature.The latest research has shown that this situation may be caused by a variation in NiTi surface treatment.The appropriate surface treatment increases the corrosion resistance. The paper presents the electrochemicalbehavior of NiTi alloy after surface modification with the use of various techniques.Design/methodology/approach: The evaluation of the electrochemical behavior of NiTi alloy was realizedboth by recording of anodic polarization curves with the use of the potentiodynamic method and by anelectrochemical impedance spectroscopy technique (EIS).Findings: Surface condition of metallic biomaterial determines its corrosion resistance. In the course of thework it was observed that the lowest values of corrosion current were recorded for the sterilized and thethermally passivated samples. The highest values of corrosion current were recorded for the ground samples.These samples obviously had also the highest corrosion rate.Research limitations/implications: The obtained results are the basis for the optimization of physicochemicalproperties of the metallic biomaterial. The future research should be focused on selected specific implantsspecially with respect to their application features.Practical implications: On the basis of the obtained results it can be stated that the suggested surface treatmentcan be applicable for medical implants due to the increase of the corrosion resistance and in consequence theincrease of biocompatibility.Originality/value: The paper presents the influence of various methods of the surface treatment on corrosionresistance of the NiTi alloy. The suggested methods can be applied in treatment of the material intended formedical applications especially in cases where the surface roughness plays important role.
Corrosive-Wear Behavior of Mo Modified Ti6Al4V Alloy by Wear-Electrochemical Noise Method

ZHANG Min,MA Yong,ZHANG Xiang-yu,FAN Ai-lan,TANG Bin,

摩擦学学报 , 2012,
Abstract: The Mo surface modified layer on Ti6Al4V substrate is obtained by plasma surface alloying. The structure and composition of the Mo surface modified layer are investigated by X-ray diffraction (XRD) and glow discharge optical emission spectroscopy. The duplex Mo modified layer contains a pure Mo coating on subsurface and diffusion layers between the subsurface and substrate. XRD analysis of the Mo modified layer reveals that a Mo phase exists in the modified layer with <110> and <211> orientations in the subsurface. Corrosion-wear behaviors of Ti6Al4V substrate and Mo modified Ti6Al4V alloy sliding against corundum are investigated with the wear-electrochemical noise technique in a 0.5mol/L NaCl solution. Results indicate that the Mo modified layer improves the antiwear and friction reduction properties of Ti6Al4V. Moreover, the Mo modified layer improves self-corroding electric potentials and decrease the current of Ti6Al4V. The Mo modified layer can improve the corrosion-wear behavior of Ti6Al4V.
TiO2 and SiO2 layer deposited by sol-gel method on the Ti6Al7Nb alloy for contact with blood  [PDF]
W. Walke,Z. Paszenda,P. Karasiński,J. Marciniak
Archives of Materials Science and Engineering , 2012,
Abstract: Purpose: The study contains the analysis of TiO2 and SiO2 surface modification impact on physical and chemical characteristics of Ti-6Al-7Nb alloy samples in the solution simulating cardiovascular system.Design/methodology/approach: Sol-gel coatings were selected on the ground of data taken from literature. The base of stock solution consisted of silicon dioxide precursor SiO2 (TEOS) and titanium oxide precursor TiO2. Application of SiO2 and TiO2 coating on the surface of Ti alloy was preceded by mechanical working – grinding (Ra = 0.40 μm) and mechanical polishing (Ra = 0.12 μm). Corrosion resistance tests were performed on the ground of registered anodic polarisation curves and Stern method. Electrochemical Impedance Spectroscopy (EIS) was also used in order to evaluate phenomena taking place on the surface of the tested alloys. The tests were made in artificial blood plasma at the temperature of T = 37.0±1°C and pH = 7.0±0.2.Findings: Test results obtained on the ground of voltamperometric and impedance tests showed that electrochemical characteristics of Ti-6Al-7Nb alloy differs relative to the type of surface treatment. Practical implications: Potentiodynamic and EIS studies of corrosion resistance in artificial plasma enable to predict the behavior of modified Ti-6Al-7Nb implants in cardiovascular system. The topic proposed in the article is favourable for the development of entrepreneurship sector due to high demand on such technologies and relatively easy implementation of obtained laboratory test results in the industrial and clinical practice.Originality/value: Suggestion of proper surface treatment variants that incorporate sol-gel method is of perspective significance and will help to develop technological conditions with specified parameters of oxide coating creation on the surface of metallic implants.
Electrochemical behavior of Ti and Ti6Al4V in aqueous solutions of citric acid containing halides
Schmidt, Anelise Marlene;Azambuja, Denise Schermann;
Materials Research , 2006, DOI: 10.1590/S1516-14392006000400008
Abstract: this paper reports on an investigation of the electrochemical behavior of ti grade 2 and ti6al4v alloy in aqueous citric acid solutions with ph 2.0 containing halide ions. voltammetric studies of ti and the alloy in citric acid, with and without chloride ions, indicate that the ti and ti alloy presented a passive behavior in the test solutions used. pitting was observed at 3.0 and 2.5 v/sce for ti and ti6al4v, respectively, when bromide ions were added to the solution. in solutions containing fluoride ions, dissolution of the film occurred at potentials close to - 1.0 v/sce in both electrodes. the iodide ions oxidized on the passive oxide film at potentials close to 1.0 v/sce. eis results of the materials in citric acid solutions containing chloride ions revealed that the film's resistance increased as the applied potential rose from 0 to 1.0 v. in bromide-containing solutions, breakdown of the film was confirmed at potentials above 2.0 v/sce in both electrodes. these results suggest film reformation for ti and the alloy in solutions containing fluoride at potentials within the passive region.
Surface modification of Ti?49.8at%Ni alloy by Ti ion implantation: phase transformation, corrosion, and cell behavior  [PDF]
Yan Li,Ting Zhou,Peng Luo,Shuo-gui Xu
- , 2015, DOI: https://doi.org/10.1007/s12613-015-1144-5
Abstract: The Ti?49.8at%Ni alloy was modified by Ti ion implantation to improve its corrosion resistance and biocompatibility. The chemical composition and morphologies of the TiNi alloy surface were determined using atomic force microscopy (AFM), auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). The results revealed that Ti ion implantation caused the reduction of Ni concentration and the formation of a TiO2 nano-film on the TiNi alloy. The phase transformation temperatures of the Ti–TiNi alloy remained almost invariable after Ti ion implantation. Electrochemical tests indicated that the corrosion resistance of TiNi increased after Ti ion implantation. Moreover, the Ni ion release rate in 0.9% NaCl solution for the TiNi alloy remarkably decreased due to the barrier effect of the TiO2 nano-film. The cell proliferation behavior on Ti-implanted TiNi was better than that on the untreated TiNi after cell culture for 1 d and 3 d.
Microstructure and Electrochemical Behavior of in Vitro Ti-26Nb, Ti-26Zr and Ti-26Ta Alloys Processed by Levitation Melting Technique
American Journal of Materials Science , 2012, DOI: 10.5923/j.materials.20120203.08
Abstract: This paper presents a study on microstructure, elasticity modulus and electrochemical behavior of Ti-26Nb, Ti-26Zr and Ti-26Ta binary alloys obtained in an induction furnace equipped with a water cooled copper crucible which can promote levitation of the moltem alloys. The microstructures and eletrochemical behavior were investigated by means of X-ray fluorescence spectroscopy, X-ray diffractometry, optical microscopy, microvickers hardness, open circuit potential, corrosion potential and polarization resistance. The results revealed that the difference in nominal chemical composition related to contamination was extremely low, which indicates that this melting technique is highly appropriate for obtaining contaminant-free titanium alloy. The addition of niobium was very favorable for obtaining near-β alloy with a low elasticity modulus. Additionally, alloy Ti-26Nb presented the best corrosion resistance combined with low elasticity modulus.
The effect of hydrogen peroxide on the electrochemical behaviour of Ti-13Nb-13Zr alloy in Hanks' solution
Assis, Sérgio Luiz de;Costa, Isolda;
Materials Research , 2006, DOI: 10.1590/S1516-14392006000400014
Abstract: titanium alloys are largely used for biomedical applications mainly due to their high corrosion resistance resulting from the protective oxide film formed on their surface. the literature, however, has pointed out discrepancies between in vitro tests and in vivo tests. these discrepancies have been ascribed to hydrogen peroxide (h2o2) generated by inflammatory reactions. in this investigation the electrochemical behaviour of a ti-13nb-13zr alloy, which was developed as material for implants, has been evaluated in hanks' solution, with and without h2o2. the evolution of the electrochemical behavior was monitored by electrochemical impedance spectroscopy (eis) and the results were fitted to an equivalent circuit that simulates an oxide film as a duplex layer structure composed of an inner barrier layer and an outer porous layer. in the solution without h2o2, the oxide film was very stable during the whole test period. on the other hand, in the solution with h2o2, the eis results varied significantly, indicating a progressive decrease in the barrier layer resistance until 35 days which was followed by the restoration of the barrier layer protective characteristics against corrosion, either due to its growth or to its self-healing after partial consumption of the oxidant agent. the oxide film formed on the ti alloy samples after 125 days of immersion in hanks' solution, either with or without h2o2 was analyzed by xps. the xps results revealed the presence of tio and tio2 on the samples immersed in the two electrolytes, however, ti2o3 was only found on the samples exposed to the h2o2 containing solution.
Electrochemical Evaluation of Wrought Titanium -15 Molybdenum Alloy for Dental Implant Applications in Phosphate Buffer Saline
Bhola,Rahul; Bhola,Shaily M.; Mishra,Brajendra; Olson,David L.;
Portugaliae Electrochimica Acta , 2010,
Abstract: ti-15mo alloy has been evaluated for its electrochemical behavior in phosphate buffer saline solution at the physiological temperature of 37 oc. a two time constant model of a duplex oxide layer has been used to assess the corrosion behavior of the ti-15mo alloy-solution interface using electrochemical impedance spectroscopy (eis). interfacial characteristics of the inner barrier layer and the outer porous layer have been studied to understand the role of the alloy as an implant. ti-15mo alloy shows a very high barrier layer resistance and a tendency to resist localized corrosion.
Electrochemical Evaluation of Wrought Titanium -15 Molybdenum Alloy for Dental Implant Applications in Phosphate Buffer Saline  [cached]
Rahul Bhola,Shaily M. Bhola,Brajendra Mishra,David L. Olson
Portugaliae Electrochimica Acta , 2010,
Abstract: Ti-15Mo alloy has been evaluated for its electrochemical behavior in phosphate buffer saline solution at the physiological temperature of 37 oC. A two time constant model of a duplex oxide layer has been used to assess the corrosion behavior of the Ti-15Mo alloy-solution interface using electrochemical impedance spectroscopy (EIS). Interfacial characteristics of the inner barrier layer and the outer porous layer have been studied to understand the role of the alloy as an implant. Ti-15Mo alloy shows a very high barrier layer resistance and a tendency to resist localized corrosion.
Behavior of anodic layer in Ringer’s solution on Ti6Al4V ELI alloy after bending  [PDF]
E. Krasicka-Cydzik,A. Kierzkowska,I. Glazowska
Archives of Materials Science and Engineering , 2007,
Abstract: Purpose: Characterization of the electrochemical behavior of anodized implant rods made of the titanium alloy Ti6Al4V ELI after immersion in air-saturated Ringer’s solution was presented in the paper.Design/methodology/approach: The anodized and deformed by bending at angle 20o specimens (dia 6 mm) were characterized electrochemically in two zones: the max tensile (I) and the max. compressive stress (II). Impedance spectra (EIS) and corrosion potential measurements were performed on 1, 6, 10 and 16th day after immersion in Ringer`s solution.Findings: Bending caused an apparent decrease of the protective properties of the anodic layer, but the characteristic two-layer anodic film and the values of corrosion potentials were restored due to immersion in Ringer’s solution. The regions of the compressive stresses show much stronger tendency to regenerate surface properties.Research limitations/implications: The electrochemical tests in Ringer’s solution performed only in static conditions will be followed by fatigue tests in SBF.Practical implications: Results of the work are of great importance for surgical practice in the pre-operative stage of spinal surgery procedures. The explanation of the observed phenomena is proposed.Originality/value: Different stress zones formed on implant alloy during bending were described electrochemically. Results of studies evidenced that changes in the electrochemical behaviour in vitro in Ringer’s solution are advantageous with regard to the protective properties of the investigated alloy.
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