Anodized Samples Research Articles

Improving Photoelectrochemical Properties of Anodic WO3 Layers by Optimizing Electrosynthesis Conditions.

Although anodic tungsten oxide has attracted increasing attention in recent years, there is still a lack of detailed studies on the photoelectrochemical (PEC) properties of such kind of materials grown in different electrolytes under various sets of conditions. In addition, the morphology of photoanode is not a single factor responsible for its PEC performance. Therefore, the attempt was to correlate different anodizing conditions (especially electrolyte composition) with the surface morphology, oxide thickness, semiconducting, and photoelectrochemical properties of anodized oxide layers. As expected, the surface morphology of WO3 depends strongly on anodizing conditions. Annealing of as-synthesized tungsten oxide layers at 500 °C for 2 h leads to obtaining a monoclinic WO3 phase in all cases. From the Mott-Schottky analysis, it has been confirmed that all as prepared anodic oxide samples are n-type semiconductors. Band gap energy values estimated from incident photon−to−current efficiency (IPCE) measurements neither differ significantly for as−synthesized WO3 layers nor depend on anodizing conditions such as electrolyte composition, time and applied potential. Although the estimated band gaps are similar, photoelectrochemical properties are different because of many different reasons, including the layer morphology (homogeneity, porosity, pore size, active surface area), oxide layer thickness, and semiconducting properties of the material, which depend on the electrolyte composition used for anodization.

Thermo-mechanical stress analyses of solid oxide fuel cell anode based on three-dimensional microstructure reconstruction

During high-temperature operation of a solid oxide fuel cell, the stresses caused by mismatch of thermal expansion coefficients between different materials and external mechanical loads may cause the rising of damage risk of nickel-yttria-stabilized zirconia anode. It is quite difficult to quantify the mechanical characteristics of a composite anode without investigating on the stress distribution in its real microstructure. However, the high operating temperature and extremely complex microstructure in micro-scale determine the high difficulty in in-situ measurement of thermo-mechanical stress distribution. In this work, the microstructures of six different anode samples, fabricated by using identical nickel oxide-yttria-stabilized zirconia powder mixture, are reconstructed in three-dimension based on the dual-beam focused-ion-beam-scanning-electron-microscopy. The three-dimensional thermo-mechanical stress distributions of different microstructures are conducted at operating temperature based on the finite element method. The effects of both thermal expansion coefficients mismatch between nickel and yttria-stabilized zirconia and external mechanical loads are analyzed. The mechanical failure probabilities of yttria-stabilized zirconia phase in different reconstructions are estimated based on the obtained stress distributions to investigate the influence of microstructure characterizations on nickel-yttria-stabilized zirconia anode strength.

Na-Ti-O nanostructured film anodically grown on titanium surface have the potential to improve osteogenesis

Titanium (Ti) is widely used in the field of hard tissue implant materials due to its desirable mechanical properties and biocompatibility, but its osteogenic activity is relatively poor, hindering its clinical applications. In this work, Na-Ti-O nanostructured film was prepared on Ti surface by anodization in 2 M NaOH electrolyte at different applied voltages. The results show that uniform film can be formed when the voltage is between 15 and 25 V. Compared with untreated Ti, the anodized samples can promote osteoblast spreading, proliferation, and osteogenic differentiation. These results indicate Na-Ti-O nanostructured film is promising to functionalize Ti-based materials for dental and orthopedic applications.

Absorption, discharge, and internal partitioning behavior of hydrogen in the tantalum and tantalum oxide system investigated by in situ oxidation SIMS and ab initio calculations

Hydrogen behavior in tantalum and tantalum oxide thin films was examined using the in situ oxidation secondary ion mass spectrometry (in situ oxidation SIMS) method previously developed by the authors. Oxidation of Ta films by the introduction of O2 into the sputter deposition chamber immediately after film growth was found to reduce the amount of H absorbed in the Ta films by 2.7 times for samples exposed to lab air at ambient temperature; the difference increased to 4.8 times for samples exposed to air at 300 °C. From these results, it is apparent that Ta absorbs H from H2 or through reaction with H2O in air and that an oxide film “cap” largely stymies H absorption. To investigate the redistribution of hydrogen during oxidation of Ta, sputtered Ta films were implanted with deuterium, and some were subsequently anodized. In situ oxidation SIMS analysis of Ta2O5/Ta bilayer films created by anodization of deuterium (D)-implanted Ta films revealed no deuterium in the upper Ta2O5 portion; however, the total amount of deuterium detected in the underlying Ta layer of the anodized samples was close to the total amount of deuterium measured in the Ta layer of a nonanodized, D-implanted Ta film. These results indicate that during anodization, D is concentrated in the residual metal region as it is excluded from the growing oxide film. Ab initio calculations of H interstitial defects in Ta and Ta2O5 revealed that the heat of formation, ΔH, for H interstitial defects in Ta is 1.31 eV lower than that of Ta2O5; this result is consistent with the observed H blocking property of oxide films and the observed redistribution of D from oxide to metal during anodization.

Macrocell corrosion of steel in concrete: Characterization of anodic behavior in relation to the chloride content

AbstractThis study presents the determination of electrochemical properties of active steel in mortar, based on inverse numerical modeling that focuses on their dependency on chloride content. An experimental campaign, consisting of galvanic coupling tests between anode samples contaminated with different chloride concentrations and cathode samples without chlorides, was carried out. Cathode polarization tests allowed for directly determining passive steel electrochemical parameters. Anode polarization tests coupled with a numerical optimization were then performed for quantifying active steel parameters and focusing on chloride's effect on the iron anodic Tafel coefficient. Furthermore, the steel electrochemical properties were successfully used as input parameters to model the galvanic experiments.

2-D microflow generation on superhydrophilic nanoporous substrates using epoxy spots for pool boiling enhancement

Abstract We conduct an experimental investigation on the pool boiling enhancement in DI water on nanoporous surfaces. The surfaces are modified by anodic oxidation, and cavities with 2 mm diameter and pitches between 2.5 and 5 mm applied on them using EDM method filled with a two-part epoxy with low thermal conductivity properties. The capillary wicking action of the superhydrophilic nanoporous oxide layer enhances the rewetting and spreading of the liquid to dry-spots during boiling. The epoxy disks remain wet and prevent merging bubbles during the pool boiling experiment and a 2-D microflow is induced toward dried regions with synergic effects of nanoporous surface absorption, create a considerable delay in the formation of a vapor blanket. The results indicate that the anodized surface enhances the critical heat flux (CHF) by 33% and the heat transfer coefficient increases by 48% at the CHF compared to the non-coated substrate. It has been shown that for anodized samples with 3 and 4 mm epoxy spot pitches the CHF equals to 144 and 133 W/cm2, respectively, considerably higher than the coated surface without epoxy parts 125 W/cm2.

The Role of Anodization in Naturally Cooled Heat Sinks for Power Electronic Devices

Abstract Effect of anodization on the thermal performance of naturally cooled heat sinks in power electronic devices made of die-cast aluminum alloy A380 and machined aluminum alloy 6061 was investigated experimentally and numerically. Various types of anodization were examined with different thickness of anodic aluminum oxide layer (AAO), pore size distributions, and surface coloring conditions. A customized natural convection and thermal radiation experimental chamber was built to measure the cooling capacity and heat sink temperatures. A 3D numerical model was also developed and validated against the collected data to provide more details into the contribution of the radiation heat transfer. The total emittance of the anodized samples was determined by a Fourier transform infrared reflectometer (FTIR) spectroscopy method. The results show a significant improvement in total hemispherical emissivity from 0.14 to 0.92 in anodized die-cast aluminum samples. This increase resulted in a considerable reduction in overall thermal resistance, up to 15%; where up to 41% of the total heat dissipation was contributed by thermal radiation. In spite of the rather distinguishable surface morphologies, the measurements suggested that thermal emissivity of the anodized die-cast Al A380 and Al alloy 6061 samples were in the same range.

Structural, mechanical and electrical properties of NiO - GDC20 composite anodes for low or intermediate temperature solid oxide fuel cells

Nano Composites NiO and 20 mol% gadolinium doped ceria (GDC20) were synthesized as X (NiO) +1-X (Ce0.8 Gd0.2 O2-δ) where (X = 40& 45 wt. %) for intermediate or low temperature operating solid oxide fuel cells (SOFC). For composite anode materials, NiO and GDC20 nano powders were mechanically mixed and calcined from 600 °C to 750 °C. Samples were pelletized and sintered at 1300°C. Systematic study of structure, purity, phase and structural parameters of anode samples were carried out by XRD and SEM. Mechanical strength of anode composites were estimated by Vickers micro-hardness and observed that microhardness of composites are varying from 9.37 GPa to 11.25GPa. Electrical properties D.C conductivity and A.C conductivity of anode composites were computed using four probe method and impedance analyser respectively. The A.C conductivity and their activation energies of the anode samples (compositions X = 40 & 45 wt. %) were computed from RT to 500°C with the impedance spectrosopy data and the conductivities are found 2.95 x 10−3 S/cm and 7.53 x 10−2 S/cm respectively at 500°C (frequency 1.33 MHz). The activation energies of A.C conductivity have observed that decrease with increase in frequencies.

Microstructure and Properties of Nanostructured Coating on Ti6Al4V.

Implant surface properties of Ti6Al4V alloy that is currently used as a biocompatible material because of a variety of unique properties can be improved by a self-organized TiO2 layer. The TiO2 nanotubes forming on the titanium-based materials is a relatively recent technology for the surface properties modification and represents pronounced potential in promoting cell adhesion, proliferation, and differentiation that facilitate an implant osseointegration. This work focuses on the influence of surface treatment quality and anodic oxidation parameters on the structure features and properties of TiO2 nanotube coatings. The nanotubes were formed on Ti6Al4V alloy substrates by simultaneous surface oxidation and controlled dissolving of an oxide film in the presence of fluorine ions. The anodization process on ground or polished samples was performed at experimental condition of 30 V for 1 h. The selected anodized samples were heat treated for 2 h at 500 °C under flowing argon. All samples were characterized by scanning electron microscopy, X-ray diffraction analysis, and Raman spectroscopy. The corrosion rate in physiological solution reached 0.0043, 0.0182, and 0.0998 mm per year for the samples in polished and not-anodized, as-anodized, and anodized-heat treated conditions, respectively.

Coral-flake Co particles electrodeposited into the porous NiAl matrix

The synthesis of nanoscale arrays of magnetic particles, which may be used in magnetic recording devices, has attracted considerable interest recently. The coral-flake Co particles were electrodeposited into the pores of the porous NiAl matrix. Compared with the nonanodized samples, the anodized samples in H3PO4 solution formed thicker Al2O3 during the production of ordered Co particle arrays into the porous NiAl matrix. The deposition at a negative potential resulted in increased imax and decreased tmax. The diameter of Co particles increased with increasing deposition time. The interspace of Co was consistent with the interspace of pores distributed in the NiAl matrix. The coercivity (Hc) and the ratio of remanent magnetization to saturation magnetization (Mr/Ms) decreased with increased growth rate of the porous NiAl matrix at the same deposition time. Hc and Mr/Ms also decreased with the prolonged deposition time due to increasing Co size.

Electrophoretic encapsulation for slow release of vancomycin from perpendicular TiO2 nanotubes grown on Ti6Al4V electrodes

Ordered perpendicular TiO2 nanotubes (TNT) with 405 to 952 nm length and 60 to 90 nm diameter were grown via 40 to 120 min anodization of Ti6Al4V flat substrates. The samples were called TNT-40, −60, −80, −100, and −120. Vancomycin was loaded on the bare and anodized electrodes by separate immersion and electrophoretic (EP) deposition procedures. EP loading resulted in storage capacity of 5221.86 μg cm−2 for TNT-80 which was much higher than 1036.75 μg cm−2 of immersed sample. Drug release comprised of three stages: (i) burst release (78% for the bare, and 23% for the TNT-80 sample), (ii) gradual transport (21% for the bare, and 64% for the TNT-80 sample), and (iii) equilibrium. Transfer from all electrophoretically loaded TNT samples obeyed semi-infinite diffusion mechanism with a diffusion coefficient of 1.5 × 10−15 cm2 s−1. However, for bare specimens, external transfer prevailed. Anti-bacterial tests showed a bacteria-free region of 318 mm2 on the drug-loaded anodized samples during the initial stage of drug release; while 254 mm2 of bacteria-free region existed on the drug-loaded bare plates. Drug loading capacity of the anodized samples was enough for most biomedical applications. Ti6Al4V anodization proved a viable strategy for prosthesis drug loading and release.

Influence of electrolytic parameters in the formation of TiO2 nanotubes over Ti6Al4V

Metallic biomaterials are widely used in the orthopaedic research field for bone fixation, prosthetic device as well as in dental applications. Titanium-based alloys are considered a suitable candidate for implant-based applications because of its specific material property. Among various materials explored, Ti6Al4V is a promising material which has been widely used for implant applications. Surface property of these alloys plays a major role in most of the applications. In this regard, modification of the surface by nanodesigning has been utilized to improve the surface properties of the titanium and its alloys for biomedical application. However, certain parameters are needed to control the surface morphology of the alloy. Thus, in order to get titania (TiO2) nanotubes arrays over the Ti6Al4V alloy different electrolytes has been used. In the present study, Ethylene glycol (EG) and Ethylene glycol and Distilled water (EGDW) with ammonium fluoride salt were used as electrolytes. Voltage was kept constant in both the electrolytes. Moreover, diameter of the formed nanotubes was found to be changed when anodization was done in two different electrolytes. Inner and outer diameter of the as-synthesized nanotubes when anodization carried out in ethylene glycol was found to be 43.3571 nm and 93.6288 nm respectively. Whereas inner and outer diameter of as developed nanotubes when anodizing was carried out in Ethylene glycol and Distilled water (EGDW) was found to be 33.8484 nm and 89.9901 nm respectively. Moreover, as-synthesized anodized samples were heat-treated at 450 °C for 3 h. The prepared samples were characterized by scanning electron microscopy and XRD to study the phase change and the tube diameter in the developed nanostructure.

Behavior of glycerol concentration in a HCl electrolyte for obtaining Titania nanostructures by anodic oxidation

ABSTRACTIn this work, the anodization of grade 2 titanium was performed using a HCl-based electrolyte in order to obtain Titania nanostructures. Different glycerol concentrations were added to the HCl electrolyte to study the effect it has on the shape and density of the nanostructures, additionally, anodization time and voltage was also varied. The anodized samples were observed by SEM microscopy and studied by Raman spectroscopy and X-ray diffraction. Raman spectroscopy and XRD showed the formation of the anatase phase of the TiO2. By SEM it was possible to observe several changes in the shape of the structures, by adding glycerol ball-like structures were visible, anodization time did not change the shape of the nanostructures. However, the voltage variation showed a clear control on the shape of the structures, forming nanotubes at higher voltages. It was concluded that a better control of the shape and density of the nanostructures is achieved by adding glycerol, however, in order to overcome the resistance that the electrolyte brings, higher voltages are required.

Experimental Optimization of Ni-GDC Microstructure with Various Phase Fractions for Solid Oxide Fuel Cell Anode

The design of electrode microstructure is important to enhance performance and stability of solid oxide fuel cells (SOFCs). The most common material used for the fuel electrode is nickel-yttria stabilized zirconia (Ni-YSZ) composite, in which electron, ion and gas conduct in the metallic Ni phase, the ceramic YSZ phase and the pores, respectively. The electrochemical reaction therefore takes place at the triple-phase-boundary (TPB), hence the increase in TPB density improves electrode performance. Recently, the ceramic materials, which exhibits mixed ionic-electronic conductivity (MIEC) properties, are considered to be beneficial solution for the SOFC electrodes. They can greatly enhance the available reaction sites by introducing surface reactions on the double phase boundaries (DPB) between MIEC phase and pore. One of the promising materials is considered to be gadolinium doped ceria (GDC). GDC exhibits higher ionic conductivity compared to YSZ and has MIEC property in the reducing atmosphere. In the case of Ni-GDC composites, the electrochemical performance is supported by both DPB and TPB reactions. In general, the active DPB density increases with the share of GDC phase in the composite. On the other hand, the active TPB density achieves maximum value when the share of both solid phases is balanced. The optimal electrode design has to be determined by the ratio between DPB and TPB reactions and their kinetics. In the present study, electrolyte supported SOFC with Ni-Gd0.1Ce0.9O2-δ anodes with various phase fractions were fabricated and their polarization characteristics were experimentally investigated. The ratio of Ni and GDC was controlled by the initial powder composition, and the porosity was varied by isostatically pressing the anode after screen printing. Initially, NiO (AGC Seimi) and GDC (ShinEtsu) powders were mixed to achieve the target volume fractions of Ni:GDC = 70:30, 60:40, 50:50, 40:60, 30:70 vol%. The anodes were then screen-printed on the YSZ discs and calcinated at 1350oC. In order to modify the porosity of the anodes, some of the cells undergoes isostatic pressing treatment at 200 MPa for 30 minutes prior to the calcination. The LSCF (lanthanum strontium cobalt ferrite by Fuel Cell Materials) cathode with GDC (ShinEtsu) barrier layer were screen-printed and sintered on the other side of the electrolyte. Current – voltage curves and electrochemical impedance spectra were measured at 500 – 800 oC. Additionally, the anodes with optimal phase composition were discharged for 100 hrs. 3D microstructural analysis was conducted with the focused ion beam scanning electron microscopy (FIB-SEM). The microstructural parameters, such as phase volume fractions, particle intercept length, TPB and DPB densities and tortuosity factors were quantified. By evaluating the connectivity of each phase, the total and active TPB and DBP densities were calculated. Quantified microstructural parameters were correlated with the polarization characteristics. Neither the DPB reactions nor the TPB reactions could individually explain the measured polarization resistances of the composite anodes. In the case of screen-printed anode samples without isostatic pressing, the high porosity (ca. 52% for all of the samples) lead to low connectivity of the solid phases. The optimal composition of the cermet was found to be Ni:GDC = 0.4:0.6 vol%. Introducing isostatic pressing, improvements in both ohmic and polarization resistances are observed. The decrease in ohmic resistance is mainly attributed to the improved connectivity between the electrode and the electrolyte. The polarization resistance was influenced by the changes in active DPB and TPB densities. As the porosity is reduced and connectivities of the solid phases are enhanced by the isostatic pressing, not only the nominal values of active DPB and TPB densities increased, but also the ratio between them has changed. This effect is most significant for Ni:GDC = 0.3:0.7 vol% sample, which exhibits the smallest polarization resistance among all the investigated electrodes. The discharge testing showed the improved stability of the cells with the decreased porosity. It is therefore concluded that not only the ratio between Ni and GDC but also porosity is a very important parameter for the performance and stability of the anode. Figure 1

Improving photocatalytic decomposition by MWCNT and anodized α-Fe2 O3 composite

In recent years, photocatalytic technology has received attention for environmental protection. In this study, the usefulness of iron nanostructures generated by anodization was confirmed. Moreover, the synergistic effect of anodized iron (hematite, α-Fe₂O₃) and MWCNT (multi-walled carbon nanotube) was confirmed by methylene blue (MB) decomposition by MWCNT /α-Fe₂O₃ composite material. Electrophoretic deposition(EPD) was used as a method of making the MWCNT/α-Fe₂O₃ composite material. Characterization of the anodized samples and samples after EPD was performed by SEM and XRD, and concentration measurement of MB decomposition was performed using a spectrophotometer. The MB decomposition rate was improved in all the samples with MWCNT and the highest obtained with the MWCNT/α-Fe₂O₃ sample

Influence of Organic Acids on the Surface and Corrosion Resistant Behavior of Anodized Films on AA2024 Aerospace Alloys in Artificial Seawater

This study aims to evaluate the influence of dicarboxylic acids (oxalic, malonic and succinic acid) used in anodization bath on the surface and corrosion resistant performance of anodized films on AA2024 aerospace grade alloys. The surface morphology, topography, composition and structure of anodized samples were examined by scanning electron microscopy, optical profilometer, X-ray diffraction and attenuated total reflectance-infrared techniques. Characterization results revealed the effect of dicarboxylic acids addition on the anodized film’s surface with important changes. X-ray Photoelectron Spectroscopic analysis confirmed the presence of carboxylic groups on the porous anodized layer processed in anodization bath containing succinic acid. The electrochemical corrosion tests specified a solid relationship between the corrosion resistance and the surface microstructure of the anodized layer processed in different dicarboxylic acids.

Corrosion Performance of Nano-Alumina Coatings over Anodized Aluminum Alloy by Dip Coating Method

Alumina coatings are widely used to enhance the wear, abrasion, and corrosion resistance of metal components. This investigation aims at studying the alumina sol-gel coating on the anodized aluminum alloy surface using a dip coating technique. A stable alumina coating was deposited over the anodized aluminum surface using oxime-modified aluminum(III) isopropoxide as sol-gel precursor. The scanning electron microscopy image of the coated anodized sample suggests deposition of a uniform and crack-free aluminum coating. The corrosion resistances of bare, anodized, and coated anodized aluminum alloy samples were investigated by electrochemical impedance spectroscopy and potentiodynamic polarization in 3.5 wt % aqueous NaCl solution. An appreciable shifting was observed in the equilibrium corrosion potential (Ecorr) and the corrosion current density (icorr) values of both anodized and coated anodized samples: i.e. Ecorr: from –1377.11 mV (anodized) to –711.54 mV (coated anodized) and icorr: from 80.37 μA/cm2 (anodized) to 0.090 μA/cm2 (coated anodized). The results clearly indicate the corrosion resistive behavior of nano-alumina coatings.

Mechanical testing of antimicrobial biocomposite coating on metallic medical implants as drug delivery system.

Post-operative infection often occurs following orthopedic and dental implant placement requiring systemically administered antibiotics. However, this does not provide long-term protection. Over the last few decades, alternative methods involving slow drug delivery systems based on biodegradable poly-lactic acid and antibiotic loaded hydroxyapatite microspheres were developed to prevent post-operative infection. In this study, thermally anodised and untreated Ti6Al4V discs were coated with Poly-Lactic Acid (PLA) containing Gentamicin (Gm) antibiotic-loaded coralline Hydroxyapatite (HAp) are investigated. Following chemical characterization, mechanical properties of the coated samples were measured using nanoindentation and scratch tests to determine the elastic modulus, hardness and bonding adhesion between film and substrate. It was found that PLA biocomposite multilayered films were around 400nm thick and the influence and effect of the substrate were clearly observed during the nanoindentation studies with heavier loads. Scratch tests of PLA coated samples conducted at ~160nm depth showed the minimal difference in the measured friction between Gm and non Gm containing films. It is also observed that the hardness values of PLA film coated anodised samples ranged from 0.45 to 1.9GPa (dependent on the applied loads) against untreated coated samples which ranged from 0.28 to 0.8GPa.

Comparative study of CO oxidation on biogenic lepidocrocite layered on anodic alumina samples

Leptothrix genus bacteria were cultivated in Lieske medium in presence of anodic Al2O3/Al to synthesize γ-FeOOH as a biogenic precursor for catalyst preparation. Different amounts of biogenic iron (0.6, 0.9, 9.2% Fe) were deposited. γ-FeOOH deposition on the support was identified the process being determined by the anodic Al2O3 surface structure. The catalytic activity in the CO oxidation reaction was examined by in situ diffuse-reflectance infrared spectroscopy up to 250 °C. A maximum conversion of 42% was achieved with 9.2% Fe sample. However, the lowest amount of reaction product CO2 was determined. Lepidocrocite conversion into maghemite occurred during catalytic experiments. Static adsorption study showed presence of carbonate (bidentate, monodentate) species and formates on the samples surface indicating that oxidation occurred at room temperature by CO interaction with (sub)surface oxygen. Bidentate carbonate species were not registered with 9.2% Fe sample. Additionally, inhibited formate species formation was registered on the same sample. In this case the biogenic iron coverage could be considered thicker and denser determining CO2 adsorption–desorption to/from the surface of iron-containing compound and anodic alumina. So, the higher CO conversion with 9.2% Fe sample was at the expense not only for transformation to CO2 but some part remained on the surface as strongly adsorbed species.

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.