Ti 13Nb 13Zr Alloy Research Articles

The Effect of Surface Modification of Ti13Zr13Nb Alloy on Adhesion of Antibiotic and Nanosilver-Loaded Bone Cement Coatings Dedicated for Application as Spacers.

Spacers, in terms of instruments used in revision surgery for the local treatment of postoperative infection, are usually made of metal rod covered by antibiotic-loaded bone cement. One of the main limitations of this temporary implant is the debonding effect of metal–bone cement interface, leading to aseptic loosening. Material selection, as well as surface treatment, should be evaluated in order to minimize the risk of fraction and improve the implant-cement fixation the appropriate manufacturing. In this study, Ti13Zr13Nb alloys that were prepared by Selective Laser Melting and surface treated were coated with bone cement loaded with either gentamicin or nanosilver, and the effects of such alloy modifications were investigated. The SLM-made specimens of Ti13Zr13Nb were surface treated by sandblasting, etching, or grounding. For each treatment, Scanning Electron Microscope (SEM), contact profilometer, optical tensiometer, and nano-test technique carried out microstructure characterization and surface analysis. The three types of bone cement i.e., pure, containing gentamicin and doped with nanosilver were applied to alloy surfaces and assessed for cement cohesion and its adhesion to the surface by nanoscratch test and pull-off. Next, the inhibition of bacterial growth and cytocompatibility of specimens were investigated by the Bauer-Kirby test and MTS assay respectively. The results of each test were compared to the two control groups, consisting of commercially available Ti13Zr13Nb and untreated SLM-made specimens. The highest adhesion bone cement to the titanium alloy was obtained for specimens with high nanohardness and roughness. However, no explicit relation of adhesion strength with wettability and surface energy of alloy was observed. Sandblasting or etching were the best alloys treatments in terms of the adhesion of either pure or modified bone cements. Antibacterial additives for bone cement affected its properties. Gentamicin and nanosilver allowed for adequate anti-bacterial protection while maintaining the overall biocompatibility of obtained spacers. However, they had different effects on the cement’s adhesive capacity or its own cohesion. Furthermore, the addition of silver nanoparticles improved the nanomechanical properties of bone cements. Surface treatment and method of fabrication of titanium affected surface parameters that had a significant impact on cement-titanium fixation.

Self-organized TiO2 nanotube layer on Ti–Nb–Zr alloys: growth, characterization, and effect on corrosion behavior

Ti alloys are widely applied in implanted biomedical devices due to their unique mechanical and biological performances. A strategy employed to improve bone integration on orthopedic and dental implants is to grow a self-organized TiO2 nanotube layer on the surface of titanium alloy implants. This paper describes the formation of self-organized TiO2 nanotubes on Ti–35Nb–2Zr and Ti–35Nb–4Zr alloys by the anodization process, as well as the effects of Zr content on TiO2 phase stability. The morphological and chemical characteristics of the nanotubes were analyzed by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron microscopy. In addition, a comparison was made of the electrochemical stabilities of TiO2 nanotube-coated surfaces and surfaces without nanotubes, which revealed higher corrosion resistance for the nanotube-modified surface. The electrochemical impedance spectroscopy results were fitted with two-time constant equivalent circuit representing the barrier layer (nanotube bottom) and the porous layer (nanotube wall). The addition of Zr suppressed ω-phase formation, preserving the alloy’s low elastic modulus (64 GPa). This Zr addition also delayed the anatase-to-rutile transformation and slightly increased the nanotubes’ length to 1.14 µm. These features make the Ti–35Nb–4Zr alloy a very good candidate for use in the biomedical field, especially for applications that require low elastic modulus with enhanced corrosion resistance.

Severe plastic deformation and different surface treatments on the biocompatible Ti13Nb13Zr and Ti35Nb7Zr5Ta alloys: Microstructural and phase evolutions, mechanical properties, and bioactivity analysis

Ti13Nb13Zr and Ti35Nb7Zr5Ta alloys containing non-cytotoxic elements for bone tissues can be the right choice for replacing Ti6Al4V for orthopedic implant applications. Formation of ultrafine-grained (UFG) structure in metals and alloys by severe plastic deformation (SPD) techniques allows the achievement of unique mechanical properties. Using high-pressure torsion (HPT), UFG microstructures were formed in both alloys resulting in the average size of grains/subgrains of ∼203 nm and ∼112 nm for the Ti13Nb13Zr and Ti35Nb7Zr5Ta samples, respectively. After processing by HPT, hardness measurements gave the values of about 390 HV and 320 HV, and Young's moduli of about 60 GPa and 44 GPa, respectively for the Ti13Nb13Zr and Ti35Nb7Zr5Ta alloys, being the last very close to the modulus of the bone. Additionally, surface modifications have been carried out by anodization and by chemical methods aimed to induce specific responses on osteoblastic cells after implantation. The results of bioactivity tests indicated that oxide nanostructures produced after anodization could activate the surfaces of both samples. However, chemical treatment was capable of activating only the Ti13Nb13Zr alloy. The bioactivity of the Ti13Nb13Zr alloy was much higher than the one for Ti35Nb7Zr5Ta alloy and was improved after processing by HPT.

The influence of the surface nanostructured modification on the corrosion resistance of the ultrafine-grained Ti–13Nb–13Zr alloy in artificial saliva

On the surface of the ultrafine-grained Ti–13Nb–13Zr alloy and the coarse-grained Ti–13Nb–13Zr alloy nanotubular oxide layers were formed by electrochemical anodization in the 1 M H3PO4 + NaF electrolyte in order to evaluate the electrochemical behaviour in the artificial saliva. SEM images showed that homogeneous nanotubular oxide layers could be formed by anodic oxidation of titanium alloys in an electrolyte with fluoride ions. These two titanium alloys, like other materials developed to replace the bone tissue in the human body, have to be highly corrosion resistant, which is one of the most common requirement in terms of the biocompatibility, damage and fracture prevention. The alloys were analysed by means of the electrochemical impedance spectroscopy and potentiodynamic polarization. The analyzed alloys had good corrosion stability, while nanotubular oxide layer improved their corrosion resistance.

ASSESSMENT OF TRIBOLOGICAL PROPERTIES OF Ti13Nb13Zr TITANIUM ALLOY USED IN MEDICINE

The aim of this study was to evaluate the wear and tear of titanium biomaterials used for hip endoprosthesis. The test materials were samples of titanium and its alloys: Ti grade 4, Ti6Al7Nb and Ti13Nb13Zr. Model tribological tests were carried out in reciprocal motion under conditions of technically dry friction, friction with lubrication provided by an artificial blood solution and Ringer's solution. A 6 mm in diameter Al2O3 ball was used as a counter-sample in the friction pairs. After tribological tests, traces of wear were inspected using scanning electron microscopy. A confocal microscope with interferometric mode was used to evaluate the wear of the surface of samples and counter-samples. The lowest friction coefficients among all the material associations were obtained for the Ti13Nb13Zr-Al2O3 alloy. SEM analysis has shown that as a result of the wear process, numerous scratches and grooves were generated. They were created as a result of loose products of wear moving around in the friction area. For all tested materials, a pile-up of the wear edges was observed, which indicates an abrasive wear mechanism. During the friction tests of the tested material associations, the titanium disc proved to be the most wearing material. For Ti6Al7Nb and Ti13Nb13Zr alloys, comparable wear was recorded regardless of the test conditions (TDF, AB, RS). The analysis of the obtained tribological results showed that the material association for which the lowest wear of friction pair (sample and countersample) recorded was Ti6Al7Nb-Al2O3.

Effects of electrophoretic deposition times and nanotubular oxide surfaces on properties of the nanohydroxyapatite/nanocopper coating on the Ti13Zr13Nb alloy

Load-bearing implants are developed with a particular emphasis placed on an application of ceramic hydroxyapatite coatings in order, to enhance the bioactivity of titanium implants and to shorten the healing time. Therefore, thin, fully crystalline coatings that are, highly adhesive, hydrophilic and demonstrating antibacterial properties are ly looked for. The aim of this research was to develop and characterize the properties of (nano)hydroxyapatite coatings implemented with nanocopper particles and obtained by the electrophoretic method. The deposition was carried out on the Ti13Zr13Nb alloy, either on a bare surface or a nanotubular oxide layer. The deposition was made for 1 or 2 min. The chemical composition, phase composition, coating structure, homogeneity, thickness, nanoindentation and nanomechanical properties, adhesion determined by a nanoscratch test, and wettability measured by a contact angle were investigated. The presence of nanotubular oxide layers caused no significant change in nanoindentation and nanomechanical propertie and an increase in adhesion strength and a decrease in the contact angle. The increase in deposition time resulted in an increased thickness, a decreased hardness, an increased adhesion strength and wettabilty. The observed effects in the composite (nano)HAp/Cu – (nano)TiO2 coatings are attributed to the change in the structure of coatings following the increasing deposition time and coating thickness.

Roughening of film fabricated by ultrasonic microarc oxidation on Ti–13Nb–13Zr

The fracture toughness of brittle biofilms prepared through the microarc oxidation process on the Ti–13Nb–13Zr alloy needs to be improved. The ultrasonic technology was successfully incorporated into the process. The indentation test and its analysis method were adopted to measure the film fracture toughness. The properties of the film such as surface morphology and phase composition were compared with those of a film prepared without using the ultrasonic technology, and the toughening factors were analyzed and a calculation model of fracture mechanics was established. The results show that the composite-process film has higher fracture toughness than the single-process film with a different film porosity, and the toughness of the former can reach 2·65 MPa m1/2 for higher duty cycles. Parts of titanium dioxide (TiO2) phase transformation toughening, reduction of the main-crack stress concentration by microcracks and the densification of the microstructure caused by ultrasonic cavitation effect are the main reasons that fracture toughness improved. Similar results for measurement and calculations obviously indicate the validity of the model. The composite process can achieve the purpose of toughening titanium alloy biofilms.

A study on microstructure of porous TiNbZr alloy produced as biomaterial

AbstractIn the present study, titanium‐based biomaterial (Ti‐10Nb‐10Zr) with different porosity was fabricated by sintering at different temperatures. The porosity of fabricated samples is close to natural bone; also the compression strengths of the samples are higher than that of natural bone. The phases named α and β are seen in the microstructure of samples fabricated, but α phase partially converts into β phase with increasing sintering temperature. Porosity decreases with increasing sintering temperature, and compressive strength increases with decreasing porosity. Elastic modules of fabricated samples are close to natural bone, so these materials don't cause wear of bone.

Synthesis of oxide nanotubes on Ti13Nb13Zr alloy by the electrochemical method

Surface modification of titanium alloys expands the range of their applicability in medicine, particularly in the form of various implants. Present work reports the results of the electrochemical formation of self-ordered oxide nanotubes on Ti13Nb13Zr alloy. Due to its relatively low Young modulus (77–79 GPa) this alloy can be attractive material for orthopedic application. The experiments were conducted in the (NH4)2SO4 + NH4F electrolyte at room temperature. Anodization of the alloy samples was carried out for 2 h under variable external potential U (in the range from 10 to 45 V) and the current versus time transients were recorded. Obtained surface morphology was investigated by the scanning electron microscopy and the X-ray techniques. The morphological parameters of the obtained nanotubes such as the inner (din) and outer (dout) diameters were determined. The tubes diameter dependence on the voltage of anodization process was derived. The dependence d[nm] = f(U)[V] was established at constant temperature 25 °C. It provides the basis for controlled oxide nanotubes layer growth. It was also demonstrated that these nanotubes exhibit photocatalytic activity.

Surface anodization of the biphasic Ti13Nb13Zr biocompatible alloy: Influence of phases on the formation of TiO2 nanostructures

Here we report for the first time that the anodization of the biphasic (α'+β) Ti13Nb13Zr alloy form arrays of TiO2 nanotubes with well-defined circular geometry in the α′ phase, while nanopores of TiO2 are formed in the β phase. Samples of the Ti13Nb13Zr alloy were severely plastic deformed using High-Pressure Torsion (HPT) to refine the microstructure and to redistribute α′ and β phases. The anodization was performed using an organic electrolyte (glycerol) containing fluoride ions and a few percentages of water. All the specimens coated with nanotubes were annealed at 550 °C to crystallize the modified surface of the as-anodized samples. XRD analyses confirmed that the as-anodized amorphous nanostructures crystallize in a mixture of anatase and rutile after heat treatment, and SEM observations showed no significant morphological changes in the surface phases. The evaluation of corrosion resistance showed that anodized samples have much better corrosion properties than polished ones without any evidence of pitting corrosion. Quantitative comparison between anodized coarse-grained (α'+β)-Ti alloy and ultra-fine grained (α'+β)-Ti one showed that the nanostructuring of the (α'+β)-Ti alloy by HPT helped to improve the bioactivity when compared with the coarse-grained sample.

A Facile Strategy for the Growth of an Anodic Oxidation Film of the Ti13Nb13Zr Alloy Driven by Residual Stress

A Facile Strategy for the Growth of an Anodic Oxidation Film of the Ti13Nb13Zr Alloy Driven by Residual Stress

The Influence of Laser Alloying of Ti13Nb13Zr on Surface Topography and Properties

Abstract The laser alloying is a continually developing surface treatment because of its significant and specific structuration of a surface. In particular, it is applied for Ti alloys, being now the most essential biomaterials’ group for load-bearing implants. The present research was performed on the Ti13Nb13Zr alloy subject to laser modification in order to determine the treatment effects on surface topography and its some mechanical properties like nanohardness, Young’s modulus, roughness. A pulse laser Nd:YAG was applied at three different laser pulse regimes: either 700 W, 1000 W or 1000 W treatment followed by 700 W modification at a pulse duration of 1 ms. The surface topography and morphology were examined using light microscopy and scanning electron microscopy with spectroscope of X-ray energy dispersion. The mechanical properties were determined by nanoindentation tests and surface roughness with a use of profilograph. The wettability was tested with a goniometer. The obtained results demonstrate complex behavior of the material surface: decrease in penetration distance and increase in hardness after first laser treatment, maintenance of this trend when machining using a higher laser pulse power, followed by an increase in penetration and decrease in hardness after additional laser treatment at lower power input, due to which a surface with fewer defects is obtained. The change in Young’s modulus follows the change in other mechanical properties, but not a change in roughness. Therefore, the observed hardening with the increase of the laser pulse power and then a small softening with the use of additional treatment with lower power can be attributed to some processes of remelting, diffusion and crystallization, sensitive to the previous surface state and heat energy flux. Despite that, the laser treatment always caused a significant hardening of the surface layer.

Modelling of the mechanical response of Zr–Nb and Ti–Nb alloys in a wide temperature range

This article presents the results of modeling the mechanical behavior of Zr–Nb and Ti–Nb alloys in a range of strain rates from 0.001 to 1000 1/s and temperature range 297–1273 K. A modification of constitutive equations describing the mechanical response of fine-grained and coarse-grained Zr–1Nb and Ti–13Nb–13Zr alloys in a wide temperature range is proposed. It was shown that the phase transition between the hexagonal closed packed and body-centered cubic crystal structure at elevated temperatures leads to a sharp change in strain rate sensitivity of the yield strength of Zr–Nb and Ti–Nb alloys. The proposed modifications of constitutive equations make it possible to describe the strain hardening and the strain rate sensitivity of the plastic flow stress over a wide temperature range in the coarse-crystalline and ultrafine-grained Zr–Nb and Ti–Nb alloys. The results can be used for engineering analysis of structural elements of technical systems and design of manufacturing technologies for biomedical products.

Nanotubular Oxide Layers and Hydroxyapatite Coatings on Porous Titanium Alloy Ti13Nb13Zr

Abstract The surface condition of an implant has a significant impact on response occurring at the implant-biosystem border. The knowledge of physical-chemical and biological processes allows for targeted modification of biomaterials to induce a specified response of a tissue. The present research was aimed at development of technology composing of obtaining the nanotube oxide layers on a porous titanium alloy Ti13Nb13Zr, followed by the deposition of phosphate coating. The porous substrate (porosity about 50%) was prepared by a selective laser melting of the Ti13Nb13Zr powder with the SLM Realizer 100 equipment. The nanotubular oxide layers were fabricated by electrochemical oxidation in H3PO4 + 0.3% HF mixture for 30 min. at a constant voltage of 20V. The calcium phosphate coatings were formed by the electrochemically assisted deposition (ECAD). The presence of nanotubular oxide layers with their internal diameters ranging from 30 to 100 nm was observed by SEM (JEOL JSM-7600F). The nanotubes have dimensions that facilitated the deposition of hydroxyapatite.

Effects of solution composition and electrophoretic deposition voltage on various properties of nanohydroxyapatite coatings on the Ti13Zr13Nb alloy

The purpose of the research was to establish the influence of the solution composition and the electrophoretic deposition voltage on the coating homogeneity and thickness, nanohardness, adhesion, corrosion resistance and wettability. The Ti13Zr13Nb alloy was coated by the electrophoretic technique with hydroxyapatite in a solution containing 0.1, 0.2 or 0.5 g nanoHAp in 100 mL of suspension and at voltage 15, 30 or 50 V. The scanning electron and atomic force microscopies, polarization curves technique for corrosion assessment, nanoindentation and nanoscratch tests, and measurements of contact angle in simulated body fluid were performed. The obtained results revealed the complex and interrelated effects of both process determinants on the structure and properties of hydroxyapatite coatings, which were attributed to the role of the size, shape and content in suspension of hydroxyapatite particles.

Design and fabrication of a low modulus β-type Ti–Nb–Zr alloy by controlling martensitic transformation

In this paper, high density of dislocations, grain boundaries and nanometer-scale α precipitates were introduced to a metastable Ti–36Nb–5Zr alloy (wt%) through a thermo-mechanical approach including severe cold rolling and short-time annealing treatment. The martensitic transformation was retarded, and the β phase with low content of β stabilizers was retained at room temperature after the thermo-mechanical treatment. As a result, both low modulus (57 GPa) and high strength (950 MPa) are obtained. The results indicate that it is a feasible strategy to control martensitic transformation start temperature through microstructure optimization instead of composition design, with the aim of fabricating low modulus β-type Ti alloy.

An investigation of the mechanical and microstructural evolution of a TiNbZr alloy with varied ageing time

Alloys comprised of the highly biocompatible elements titanium, niobium and zirconium have been a major focus in recent years in the field of metallic biomaterials. To contribute to the corpus of data in this field, the current paper presents results from a thorough microstructural and mechanical investigation of Ti-32Nb-6Zr subjected to a variety of ageing treatments. The presented alloy was stabilized to the higher temperature, body-centred cubic phase, showing only minimal precipitation on prolonged ageing, despite the presence of nanoscaled spinodal segregation arising from the Nb-Zr interaction. It further showed excellent mechanical properties, with tensile yield stresses as high as 820 MPa and Young’s moduli as low as 53 GPa. This leads to the ratio of strength to modulus, also known as the admissible strain, reaching a maximum of 1.3% after 6 hours ageing. These results are further supported by similar measurements from nanoindentation analysis.

Influence of surface treatment on PEDOT coatings: surface and electrochemical corrosion aspects of newly developed Ti alloy.

Surface treatment of metallic materials prior to the application of polymer coatings plays an important role in providing improved surface features and enhanced corrosion protection. In the current investigation, we aimed to evaluate the effect of surface treatment of newly developed TiNbZr (TNZ) alloys on the surface characteristics, including the surface topography, morphology, hydrophobicity and adhesion strength of subsequent poly(3,4-ethylenedioxythiophene) (PEDOT) coatings. The surface morphology, chemical composition, and surface roughness of both treated and coated alloys were characterized by scanning electron microscopy, energy dispersive spectroscopy, and optical profilometry, respectively. The adhesion strength of the coating was measured using a micro scratch machine. Furthermore, we also evaluated the performance of electrochemically synthesized PEDOT coatings on surface-treated TNZ alloys in terms of the surface protective performance in simulated body fluid (SBF) and in vitro bioactivity in osteoblast MG63 cells. Surface analysis findings indicated that the nature of the PEDOT coating (surface morphology, topography, wettability and adhesion strength) was intensely altered, while the surface treatment performed before electrodeposition facilitated the overall performance of PEDOT coatings as implant coating materials. The obtained corrosion studies confirmed the enhanced corrosion protection performance of PEDOT coatings on treated TNZ substrates. In vitro cell culture studies validated the improved cell adhesion and proliferation rate, further highlighting the important role of surface treatment before electrodeposition.

Interdiffusion and atomic mobility in bcc Ti–rich Ti–Nb–Zr system

Accurate interdiffusion information is the necessity for the control of the production of homogeneous biomedical alloys. Ternary interdiffusivities in bcc Ti–rich Ti–Nb–Zr alloys at 1273K were determined by using the combination of the diffusion couple technique and the Matano–Kirkaldy method. Subsequently, on the basis of the presently obtained interdiffusivities together with the diffusivity and mobility parameters of sub–binary Ti–Nb–Zr system and the thermodynamic descriptions for bcc Ti–Nb–Zr system, the atomic mobilities of Ti, Nb and Zr in bcc Ti–Nb–Zr alloys were assessed by means of DICTRA (DIffusion Controlled TRAnsformation) software package. Moreover, the comprehensive comparisons between the experimental diffusion properties (i.e., interdiffusivities, composition profiles, interdiffusion fluxes and diffusion paths) and the calculated/model–predicted data due to the present atomic mobilities were conducted in order to verify the reliability of the mobilities. The present atomic mobilities for bcc Ti–Nb–Zr system can provide the accurate interdiffusivity matrix over the wide composition range.

Hydroxyapatite deposition on the laser modified Ti13Nb13Zr alloy

Abstract The Ti13Nb13Zr alloy was subjected to laser modification with the Nd:YAG laser provided that such treatment would increase the surface roughness followed improved adhesion of hydroxyapatite (HAp) coatings The hydroxyapatite was deposited by electrophoretic method in suspension of 0.5 g HA powder and 100 ml ethyl alcohol. The deposition was carried out for 10 min at 10 V voltage followed by drying at room temperature for 24 h and heating at 800°C for 1 h in vacuum. The thickness of the HAp coatings was found as of about 4.06 μm to 9.05 μm. The examinations of surfaces were carried out at each stage of the experiment with the ultra-high resolution scanning electron microscope. The measurements of surface roughness after laser treatment and after HAp deposition were performed with the Hommel Etamic Waveline profilograph.