Corrosion Resistance Of Titanium Alloys Research Articles

Impact of Engineering Surface Treatment on Surface Properties of Biomedical TC4 Alloys under a Simulated Human Environment

The impact of sandblasting, anodic oxidation, and anodic oxidation after sandblasting on the surface structure and properties of titanium alloys was investigated. It was found that the surface treatments had a significant influence on the surface roughness values, contact angle values, Vickers hardness, wear resistance, and corrosion resistance of titanium alloys. The surface roughness of titanium alloys with sandblasting treatment was increased by 67% compared to untreated specimen. The Vickers hardness of titanium alloys treated with anodic oxidation after sandblasting was found to increase from 380.8 HV to 408.5 HV, which was increased by 7.3%. The surface treatments in this work improved the wear resistance of the titanium alloys to some extent, and it can be found that the wear scar width is reduced by up to 18.6%. The corrosion resistance of the titanium alloys was found to improve on anodic oxidation. Sandblasting was found to increase surface roughness and promote the formation of a porous layer during the anodization process, resulting in a slight decrease in corrosion resistance. The corrosion current density was increased by 21% compared to the untreated specimen. The corrosion current density of the titanium alloy treated with anodic oxidation decreased to 7.01 × 10−8 A/cm2. The corrosion current density was decreased by 24% compared to the untreated specimen. The corrosion current density of the titanium alloys treated with anodic oxidation after sandblasting decreased to 7.63 × 10−8 A/cm2. The corrosion current density was decreased by 8.8% compared to the specimen with anodic oxidation. The anodic oxidation provided a hydrophilic property for the surface of Ti alloys, which could show a better osseointegration characteristic than that of sandblasting. The impact of the surface treatments on surface structure and properties of titanium alloys was studied.

Role of Ta in Improving Corrosion Resistance of Titanium Alloys Under Highly Reducing Condition

Role of Ta in Improving Corrosion Resistance of Titanium Alloys Under Highly Reducing Condition

Electrochemical corrosion behavior of Ti–35Nb–7Zr–5Ta powder metallurgic alloys after Hot Isostatic Process in fluorinated artificial saliva

The present study aimed to evaluate the effect of the Hot Isostatic Process (HIP) process on the microstructure, phase stability and corrosion resistance of Ti35Nb7Zr5Ta powder metallurgy alloys. The corrosion resistance of titanium alloys was tested by analyzing the open circuit potential (OCP), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and ion release in physiological Fusayama solution. Polarization curves showed that the Ti–35Nb–7Zr–2Ta alloy presented good passivation behavior thanks to its low current densities (<10−8 A/cm2) and high polarization resistance. The interpretation of an equivalent electric circuit (EEC) demonstrated the formation of a very stable oxide film on the alloy, as indicated by good capacitive behavior, high impedance values (>106 Ω cm2) at low frequencies and phase angles close to −90° according to the EIS results with less ion release.

Electrophoretic deposition, microstructure and properties of multicomponent sodium alginate-based coatings incorporated with graphite oxide and hydroxyapatite on titanium biomaterial substrates

Multicomponent sodium alginate-based coatings reinforced with hydroxyapatite (HA) nanoparticles and graphite oxide (GtO) nanosheets consisting of graphene oxide (GO) packages were electrophoretically deposited on CP-Ti and Ti-13Nb-13Zr alloy. The suspension properties, electrophoretic deposition (EPD) mechanisms and kinetics were studied to deposit dense coatings. The coatings consisting of a sodium alginate matrix revealed a homogeneous distribution of HA nanoparticle agglomerates and GtO flakes oriented parallel to the surface of the coating. The coating topography depended significantly on the surface roughness of the substrates. GtO flakes enhanced the adhesion of coatings to the substrates. All multicomponent coatings had a hydrophilicsurface, but the hydrophilicity was higher for coatings deposited on the polished alloy substrate than for coatings obtained on the acid etched CP-Ti. The surface free energy of the coated CP-Ti substrates was about 30% higher than the one of uncoated titanium. For the coatings deposited on the alloy the surface free energy was about 65% higher than that of the alloy. The GtO/HA/sodium alginate coatings increased the corrosion resistance of titanium alloy. Considering their microstructure and properties, the newly-developed multicomponent coatings are interesting for further development of biologically enhanced titanium surfaces.

Corrosion resistance characteristics of a Ti-6Al-4V ELI alloy fabricated by electron beam melting after the applied post-process treatment methods

Post-process modifications in the form of Hot Isostatic Pressing or surface treatment methods such as sandblasting or machining have been widely used in the case of improving the quality of elements manufactured with the use of EBM (Electron Beam Melting). The corrosion resistance of titanium alloys for medical applications is a key and critical aspect for the use of personalized components as implants, especially when investigating the issue of additive manufacturing. This paper presents the results of research on the influence of HIP processing on the functional properties of the material produced with the use of EBM, considering the aspect of reconstructive medicine. Both the influence of surface modification and the influence of post-process treatment on microstructural, mechanical, and corrosion properties were investigated. A wide range of research has been carried out using scanning and transmission electron microscopy methods, in combination with three-point static bending tests and performing corrosion tests using potentiodynamic polarization and electrochemical spectroscopic impedance (EIS) in Hank‘s solution. The results showed that HIP treatment has a positive effect on the corrosive properties of the material in terms of increased corrosion resistance compared to materials not subjected to this type of post-process treatment. This fact is also related to the change of the alloy microstructure and the change of mechanical properties towards increased plasticity. In the case of the production of personalized implants with the use of EBM, it is worth considering the benefits of the HIP.

Corrosion Behavior on Titanium Alloys as OCTG in Oil Fields

Titanium alloys have been taken as Oil Country Tubular Goods (OCTG) owing to their higher strength, and better corrosion resistance, but there are some problems in their application process. The corrosion types of titanium alloys were emphatically discussed, and corrosion mechanism was analyzed in this paper. The results showed that the main corrosion type of titanium alloys in hydrochloric acid was pitting, and the surface roughness of titanium alloys could affect it. The critical current density of titanium alloys in phosphoric acid was closely related to temperature and phosphoric acid concentration. The passivation of titanium alloys could be carried out by the growing oxide film at low current density, to achieve the higher stability of passivating film in the concentrated sulfuric acid. Titanium alloys suffered from more serious corrosion in the CO2-containing completion fluid environment than that in the CO2-containing formation water environment. H2S would cause electrochemical corrosion and stress corrosion of titanium alloy pipe, leading to hydrogen embrittlement and even cracking of OCTG. Passivating film was the key to corrosion resistance of titanium alloys, and its composition would change with the depth of the film, presenting N-type. The dynamic corrosion of titanium alloys was mainly controlled by charge transfer.

Research of the peculiarities of ruthenium distribution in titanium α-, pseudo-α- and pseudo-β-alloys and its effects on corrosion resistance

The structure of deformed semi-finished products (forgings) from titanium alloys of Ti–Al–Zr + 0.15% Ru, Ti–Al–V– Mo + 0.15% Ru, Ti–Al–V–Cr–Fe–Mo + 0.15% Ru systems has been investigated. The basic mechanical properties, microstructure, results of local elemental and phase analyses obtained by X-ray spectral microanalysis and backscattered electron diffraction, as well as a model of the effect of ruthenium on increasing corrosion resistance of titanium alloys of various classes are presented.

. Вплив особливостей мікроструктури на корозійну стійкість титанових сплавів, отриманих за порошковими технологіями

. Вплив особливостей мікроструктури на корозійну стійкість титанових сплавів, отриманих за порошковими технологіями

Corrosion chemical mechanism in aggressive liquid of MAO coatings based on OT-4 titanium alloys

Microarc oxidation of alloys is widely used to obtain multifunctional coatings with unique properties. One of the topical issues in the application of the microarc oxidation is to increase the corrosion resistance of titanium alloys. In this article, the corrosion resistance of various microarc oxidation coatings of a titanium alloy in chemically aggressive liquids is determined. Comparative analysis of microarc oxidation coatings chemical resistance of the titanium alloy OT-4 showed a high coating resistance to the corrosive liquid exposure. The highest corrosion coefficient was determined when the alloy was exposed to concentrated sulphuric and hydrochloric acids. Virtually no corrosion of microarc oxidation coatings was observed in dilute acids (H2SO4 and HCl) and NaOH alkali solution.

Influence of lubricating conditions on the two-body wear behavior and hardness of titanium alloys for biomedical applications

Commercially pure titanium and titanium alloys are often preferred in biomedical applications due to their high biocompatibility behavior. However, the inadequate wear, fatigue and corrosion resistance of titanium alloys limit their use as a biomaterial in the human body. Furthermore, these alloys may contain such as aluminum and vanadium elements that can damage the nervous system. The aim of this in vitro study was to evaluate the influence of lubrication conditions on the two-body wear behavior of pure titanium, Ti-2.5Si-5Zr, Ti-5Si-5Zr, and Ti-6Al-4V using dual-axis computer-controlled wear simulator device. The mean wear volume loss of all test specimens after the two-body wear test procedures were determined to use a non-contact 3D profilometer. The alloys hardness and microstructures were evaluated using the Vickers indention method, scanning electron microscopy (SEM), X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analysis. The hardness of Ti-6Al-4V titanium alloy material was significantly greater than the other alloy materials and cp-Ti. The mean wear volume loss of Ti-5Si-5Zr test specimens was lower than the other test group specimens irrespective of lubrication conditions. It was concluded, the two-body wear resistance of the alloy formed with the addition of silica to the pure titanium is increased after both wear test procedures. However, for the test materials in this study considered, correlations between the two-body wear resistance and hardness were found to be insignificant.

TEM analysis of surface layer of Ti-6Al-4V ELI alloy after slide burnishing and low-temperature gas nitriding

Gas nitriding is one of the more effective ways of improving wear and corrosion resistance of titanium alloys, but this treatment performed at a high temperature degrades their high specific strengths. Therefore, we have subjected a Ti-6Al-4V alloy to a hybrid multi-stage treatment including turning with slide burnishing followed by gas nitriding at temperature reduced down to 540 °C. The mechanical treatment introduces a large number of defects in the form of dislocations and grain boundaries—opening additional paths for nitrogen diffusion. High resolution electron microscopy shows that after such mechanical treatment the surface is covered with an amorphous tribo-film. Below the surface, to a depth of some 100 nm, a layer of elongated dislocation cells is seen. The latter was backed by a 500 nm thick layer of strongly defected laths. Gas nitriding at 540 °C caused at first a crystallization of the tribo-layer (after 8 h), producing a mixture of nitrides and oxides. Next, below a tribo-layer, a dense layer of the δ-TiN phase is formed, with a thickness of 5 nm and 50 nm after 16 h and 24 h, respectively. Application of slide burnishing and low-temperature gas nitriding causes an increase in surface hardness by 5–10 % without compromising the strength of the core material.

Removing loose oxide layer and producing dense α-phase layer simultaneously to improve corrosion resistance of Ti-6Al-4V titanium alloy by coupling electrical pulse and ultrasonic treatment

The loose oxide layer on the surface of Ti-6Al-4V titanium alloy can be removed and a dense α-phase layer with the thickness of 11 μm can be produced simultaneously by coupling electrical pulse and ultrasonic treatment (CEPUT). In addition, after CEPUT, the surface grain is refined, the surface roughness is reduced to 0.529 μm, and the surface hardness reaches to 627 HV, showing significant gradient change. During the CEPUT, the processability of the α-phase oxygen-rich layer is improved by the electroplasticity of high peak currents, and the α-phase oxygen-rich layer produces large plastic deformation. Most of the α-phase oxygen-rich layer is removed after the CEPUT, and the remaining coarse α-phase grains are refined to form a dense α-phase layer. The corrosion resistance of the dense oxide layer on the surface has been studied. The results show that the self-corrosion current density of the sample in the NaCl solution decreases to −8.4922E-08 A/cm2 after CEPUT. Compared with the untreated sample, the self-corrosion current density is reduced by two orders of magnitude. The reason for the increased corrosion resistance of titanium alloys may be that the electrolyte is blocked by the dense and intact α-phase layer on the surface and cannot penetrate further into the titanium alloy.

Revealing the role of Ru in improving corrosion resistance of titanium alloys in HCl solution

ABSTRACTThe corrosion behaviors of CP Ti, Ti-Ru, Ti-6Al-4V-Ru (Ti-64-Ru) and Ti-5Al-5Mo-5V-1Cr-1Fe-Ru (Ti-55511-Ru) in HCl solution were investigated using open circuit potential, polarization curves, mass loss measurement and X-ray photoelectron spectroscopy. The corrosion current density of Ti-64-Ru was 5 times higher than that of Ti-55511-Ru. While the passive current density of Ti-55511-Ru was higher than that of Ti-64-Ru and a higher corrosion rate was observed in Ti-55511-Ru. Iron oxide was not detected on the Ti-55511-Ru surface. Ru increased the thickness of the passivation film of Ti from ∼49 to ∼208 nm and made it more stable. The effective role of Ru on improving the corrosion resistance of Ti alloys was revealed through direct experimental evidence.

Corrosion Behavior Of New Type Titanium Alloy As Candidate For Dental Wires In Artificial Saliva On Fluctuating Temperatures

Titanium alloys are widely used for implant material due to high biocompatibility properties. It is well known that the corrosion resistance of titanium alloys is better than other metallic materials. However, if the alloys are applied for unknown condition such as wire in orthodontic application, the fluctuating temperature is important to be considered as parameter which influences on corrosion rate. In this study, the effect of fluctuating temperature on corrosion behavior of TNTZ was investigated. Two conditions of TNTZ were used in this study, i.e., Ti-29Nb-13Ta-4.6Zr aging treatment (AT) and TNTZ solution treatment (ST). For comparison, the commercial Ti6Al4V ELI was also used in this study. The corrosion rates of the samples were characterized in artificial saliva on fluctuating temperatures range between 10°C and 50°C by immersion testing. The results showed that the lowest corrosion rate for each variation of temperature was TNTZ ST. The corrosion process seems to decrease the hardness of TNTZ up to 26 VHN. The result also showed that the corrosion rate of TNTZ is much lower than that of Ti6Al4V in all cycles. Moreover, the hardness of Ti6Al4V decreases more significantly i.e., up to 77.2 VHN. The artificial saliva with fluctuating temperature induces corrosion process and decreases the hardness of the alloys.

Electrochemical and Tribological Behavior of Surface-Treated Titanium Alloy Ti–6Al–4V

To enhance its low wear resistance, a surface treatment of ion nitriding was performed for Ti–6Al–4V titanium alloy. Structural characteristics of specimens were revealed by optical and scanning electron microscopy, and tribological behavior was evaluated using ball-on-disk tribometer by application of two different charges 5 N and 10 N. Electrochemical methods of potentiodynamic polarization curves and electrochemical impedance spectroscopy were used to evaluate the effect of this thermochemical treatment on the corrosion resistance of the studied alloy. Results showed that microhardness of nitrided Ti–6Al–4V represents a value greater with four, five times than that of the untreated alloy. The coefficient of friction was also optimized for the two charges applied. SEM analysis of the worn surfaces indicates that the wear of treated Ti–6Al–4V stills just superficial. However, electrochemical tests show that corrosion resistance of titanium alloy deteriorates after plasma nitriding.

A Study of Strontium-Doped Calcium Phosphate Coated On Ti6Al4V Using Microwave Energy

This research was carried out to improve the corrosion resistance of titanium alloy by adding strontium to calcium phosphate coating. Titanium alloy-type Ti6Al4V is widely used for biomedical and dental applications due to its good mechanical properties. To increase the lifetime span of the implantation, coating process was applied on this alloy to form a thin film and act as barrier to the implant. Surface modification was performed on Ti6Al4V by the addition of strontium-doped calcium phosphate using microwave irradiation technique to produce the coating. The different microwave irradiation times were used to study the effect on its microstructure. The resultant coatings were characterized using scanning electron microscopy, energy dispersed X-ray and X-ray diffractometer. The results from potentiodynamic polarization tests showed significant drops in corrosion current density and corrosion rate of coated samples which implied a good level of corrosion protective behaviour.

Influence of Dynamic Nonequilibrium Processes on the Mechanical Properties and Corrosion Resistance of Titanium Alloy

We compare the mechanical properties and corrosion resistance of specimens made of sheet two-phase VT22 high-strength titanium alloy in the intact state, after static tension, and after realization of dynamic nonequilibrium processes with subsequent static tension. It is shown that one-time dynamic nonequilibrium processes realized under impact vibration loading significantly increase the initial plastic deformation in this alloy and almost do not affect its corrosion resistance.

Effects Ti/TiAlN composite multilayer coatings on corrosion resistance of titanium alloy in solid NaCl-H2O-O2 at 600 °C

This paper investigates corrosion resistance of Ti-6Al-4V coated by Ti/TiAlN composite multilayer coatings with different Ti layer thicknesses in presence of solid NaCl, H2O and O2 at 600 °C. Effects of TiAlN single layer coatings with different thicknesses on the corrosion resistance of Ti-6Al-4V were also studied for comparison. The results showed that the thick TiAlN single layer coating and the Ti/TiAlN composite multilayer coating with Ti layer thickness of 0.15 μm exhibited good corrosion resistance in the above environment, while localized accelerated corrosion of substrate occurred for thin TiAlN single layer coating and Ti/TiAlN composite multilayer coating with Ti layer thickness of 0.3 μm coated specimens. It is proposed that improvement of corrosion resistance of titanium alloy by application of TiAlN single layer coating and Ti/TiAlN composite multilayer coating is attributed to suppression of active corrosion induced by gaseous metal chloride, hydrochloric acid and chlorine in the corrosion process. Accelerated local corrosion of thin TiAlN single layer coated specimen is related to existence of intrinsic through-coating defects such as pinholes in the coating. For the Ti/TiAlN composite multilayer coating with Ti layer thickness of 0.3 μm, volume expansion caused by oxidation of Ti in sublayers to TiO2 when corrosive media diffused into along through-layer defects in top TiAlN layer led to bending and cracking of the sublayers of the composite multilayer coating and eventually accelerated local corrosion of the coating and substrate.

The effect of fluoride-containing oral rinses on the corrosion resistance of titanium alloy (Ti-6Al-4V).

ObjectiveThe purpose of this study was to examine the effect of commercially available fluoride-containing oral rinses on the corrosion behavior of titanium alloys, which are the main components of orthodontic miniscrews.MethodsFour commercially available oral rinses (solution A, pH 4.46/260 ppm fluoride; solution B, pH 4.41/178 ppm fluoride; solution C, pH 6.30/117 ppm fluoride; and solution D, pH 4.17/3.92 ppm fluoride) were tested on titanium alloy (Ti-6Al-4V) circular plates, and saline was used as the control. The open-circuit potential and potentiodynamic polarization of these materials were measured. Thereafter, all samples were evaluated under a field-emission scanning electron microscope.ResultsAmong the tested oral rinses, except solution D, the more the fluoride content was, the greater was the corrosion potential downtrend; the corrosion resistance of the titanium alloy sample was also lowered significantly (p < 0.05). Field-emission scanning electron microscopic analysis of the surface morphology of the titanium alloy samples revealed that all samples had some defects, crevices, or pitting after exposure to the oral rinses than before treatment. In particular, the samples in solution A showed the most changes.ConclusionsCommercially available oral rinses having a high fluoride concentration and a low pH may reduce the corrosion resistance of titanium alloys used in dental appliances such as orthodontic titanium miniscrews and brackets.

Current advances in enhancement of wear and corrosion resistance of titanium alloys – a review

Titanium alloys have created a biomedical revolution in the past three decades and several research works are being carried out globally to combat the day to day challenges posed by the biomedical industries to meet the needs of a patient-friendly implant. Enhancement of corrosion and wear resistance of titanium alloys serve as the major treat for the stability of implant material after implantation. These problems could be overcome through various objectives, one among them being alloying titanium with non-toxic β-stabilizer elements to both increase the surface-related properties and improve biocompatibility. Other objectives include surface engineering methods such as coating, oxidation, nanograined surface and laser texturing. Overall, in this article an attempt has been made to bring out the current advances in the development of highly stable Ti-alloys with superior corrosion and wear resistance through various processes has been reviewed in detail.