Surface degradation due to wear and poor biocompatibility associated with the long-term use of biometallic implants significantly limit the clinical performance of the Ti6Al4V alloy, which is widely used in load-bearing orthopedic applications. For this reason, improving wear resistance, biocompatibility, and surface properties of Ti6Al4V alloy is of critical importance. The use of functionally graded materials (FGM) and bioceramic coatings, based on a biomimetic approach, offers an effective strategy for enhancing surface functionality. In this study, biomimetic functionally graded material (FGM) structures were obtained by combining 45S5 Bioglass (R) and P-TCP coatings deposited via electrophoretic deposition (EPD) with surfaces modified by shot peening at different intensities and their effects on tribological performance were systematically investigated. Wear tests were performed in dry and simulated body fluid (SBF) environments. With increasing Almen intensity, surface hardness increased and the highest value was obtained in sample 30ABg20 as 646.6 HV0.1. In dry wear tests, the 30ABg20 sample showed the highest tribological performance with the lowest wear rate of 1.3598 & times; 10-4 mm3/ Nm and a wear track width of approximately 267 & micro;m. In tests conducted under SBF conditions, the lowest wear rate was obtained in sample 30ABg20, with a wear track width of 1.2138 & times; 10-4 mm3/Nm and approximately 226 & micro;m.

Titanium is widely used as a biomaterial, but it suffers from poor tribological properties. Additionally, due to the stress shielding effect caused by the elastic modulus mismatch between the titanium implant and the bone, materials closer to bone elasticity have gained prominence. This study evaluates glow discharge plasma oxidation on the structural, mechanical, tribological, electrochemical, and biological properties of beta ((3) type Ti45Nb and alpha+beta (alpha + (3) type Ti6Al7Nb alloys for potential biomedical applications. Treatments were conducted at 600 degrees C, 700 degrees C, and 800 degrees C for 1 and 4 h. Phase analysis revealed rutile-TiO2 dominated oxide layer formation and oxygen diffusion into the substrate, enhancing surface hardness. Tribological tests showed a significant reduction in wear rate for both alloys, particularly at lower oxidation temperatures. Electrochemical analysis in simulated body fluid demonstrated some improvement on corrosion resistance and passivation for oxidized samples. Tribocorrosion tests confirmed the synergistic effect of wear and corrosion, with Ti45Nb showing superior performance. Biocompatibility and genotoxicity assays suggested that high temperature oxidation may reduce cell viability. Overall, low temperature plasma oxidized Ti45Nb, with its low elastic modulus and enhanced tribocorrosion resistance, emerges a promising candidate for load-bearing orthopedic implants.

In invasive procedures, biomaterials in contact with bone or soft tissue are subjected to severe erosive corrosion under the influence of hydrodynamic conditions. Therefore, it is insufficient to examine only the electrochemical corrosion performance of metallic alloys that play a role in metabolic activities. This study aims to comparatively evaluate the erosion-corrosion characteristics of eight commercially used biomaterials (Cp-Mg, AZ31, CoCrMo, NiTi, Cp-Ti, Ti45Nb, Ti6Al4V, and 316L). To simultaneously investigate mechanical and chemical interactions, biocompatible 45S5 Bioglass particles were added to simulated body fluid (SBF) at a rate of 1

Ti6Al4V alloy is widely used as an implant material but it can release harmful metal ions during its use. One of the most effective ways to improve biocompatibility of Ti6Al4V alloy is to apply surface treatments. For this reason, this study aims to investigate the effects of polyaniline (PANI) thin film coating and plasma nitriding processes, both individually and together, on the structural, morphological and corrosion properties of Ti6Al4V alloy. While the PANI thin film coated samples by PECVD and duplex coated samples were shown hydrophilic character, hydrophobic character was dominant in the plasma nitrided samples due to titanium nitride (TiN) formation on the surface. PANI coating improved the corrosion resistance of the material. Plasma nitriding also improved the corrosion resistance of the material due to the formation of protective TiN containing surface layers. Lattice and thermal mismatches hindered the obtaining much more corrosion resistance for only PANI coated, plasma nitrided and plasma nitrided + PANI coated samples. Overall results showed that the plasma nitrided + PANI film coated samples exhibited the best corrosion performance due to the protective barrier effect provided by PANI film and nitride layers.

Energy and material losses due to friction and wear during the use of materials bring about very serious costs in every sector. In order to minimize friction and wear losses of materials, different surface engineering applications are used, especially surface coatings, thermal, mechanical and thermochemical processes. On the other hand, it has been shown in recent years that the tribological properties of materials can be controlled by creating different types of biomimetic hierarchical patterns on the surface of materials. Therefore, this study investigates both the individual and the synergetic effects of both biomimetic surface textures and thermal oxidation process on the tribological performance of Ti6Al4 V alloy. For this purpose, hierarchical models were produced using the laser powder bed fusion (L-PBF) technique, which is one of the additive manufacturing methods. Snake skin, shark skin and tree frog models were used as biomimetic hierarchical models. Additionally, flat and random snake skin models were used to examine the effect of texture orientation. Moreover, thermal oxidation was carried out at 700 0C for 2 h and 4 h and the wear tests were carried out using a reciprocation-type tribo-tester under dry and simulated body fluid (SBF) conditions. As the oxidation time increased, the hardness and surface roughness of the material increased. A significant improvement in the wear rate of biomimetic models was observed compared to the non-textured sample. Lower tribological performance was observed in the tree frog model (hexagonal geometry) compared to other biomimetic models due to the presence of sharp corners. In particular, the snakeskin model provided the best wear rate because it trapped wear residue and provided additional hydrodynamic pressure. The highest tribological performances for all samples were observed in the samples oxidized at 700 0C for 4h.

Titanium alloys, especially Ti6Al4V, are widely used in in-body implants due to their superior mechanical properties, corrosion resistance and biocompatibility. However, due to their higher modulus of elasticity than bone, they do not bond well with the bone structure, leading to loosening. In addition, they contain the elements Al and V, both of which are dangerous when released into the body. Therefore, these alloys are subjected to a number of surface treatments to improve their surface properties. In this study, Ti6Al4V alloys were produced by selective laser melting in dimensions of 10x10x2 mm3 and then surface treated. The alloy surfaces were first anodized and then coated with 45S5 bioglass powder. After all surface processes, structural analyzes were performed and the effectiveness of the coating was examined. The untreated and coated samples were subjected to corrosion tests by cyclic polarization method and their corrosion behaviors were investigated.

Machine elements become unable to perform their duties as a result of fatigue damage. In addition, machine elements that are subjected to fatigue under cyclic loads are exposed to electric and magnetic fields when they are close to electrical and magnetic field sources such as electric motors. Moreover, plasma nitriding is often used to increase the fatigue strength of materials. Although the fatigue properties of surface-treated materials are frequently studied, the fatigue behavior of these materials under a magnetic field is not fully known. Therefore, this study focuses on examining the effects of magnetic field on the fatigue properties of surface-treated materials. For this purpose, AISI 4140 steel samples were plasma nitrided and subsequently post-aged, and then they were tested using a rotating bending fatigue testing system by exposing them to a magnetic field for 30 % and 100 % of their fatigue life. epsilon-Fe 2 -3 N and gamma'-Fe 4 N phases were seen in surface-treated samples, in addition to these phases, peaks belonging to the alpha"-Fe 16 N 2 phase were observed in post-aged samples. Plasma nitriding raised the hardness of the material because of nitride phases and alpha"-Fe 16 N 2 caused an extra increase. The highest diffusion depth was seen in the post-aged samples because post-aging facilitated the diffusion of nitrogen. Surface treatments increased the fatigue strength of the material. All samples tested under a magnetic field exhibited higher fatigue strength than samples tested without a magnetic field because fatigue crack initiation was prolonged by the magnetic field. Compared to non-magnetic and 30 % magnetic samples, the fatigue strengths of the samples in a 100 % magnetic field were lower. Furthermore, it was observed that applying a magnetic field had no effect on the samples ' fractographic structure.

Implants and prostheses, which are used to replace a missing or damaged structure in living organisms, must show all the necessary mechanical, tribological, electrochemical and biocompatibility properties together. CoCr alloys are often preferred biometals for their good mechanical strength and wear resistance, especially in dental and orthopedic implants. Although these alloys show good corrosion resistance in terms of electrochemical behavior as well as other good properties, when CoCr alloys come into contact with bone tissue, their surfaces show bioinert properties in terms of tissue formation between the implant and bone tissue. Therefore, both their corrosion behavior and biocompatibility properties need to be improved. In this study, CoCrW alloys produced by selective laser melting were coated with commercial 45S5 bioglass powder, a bioactive material, by electrophoretic deposition method. In order to improve the adhesion after coating, CoCrW alloys were subjected to electrochemical etching process during coating. After the coating process was completed, untreated, oxidized, untreated-coated and oxidized-coated samples were examined by electrochemical impedance spectroscopy (EIS) after open circuit potential measurements to investigate their corrosion behavior. As a result of the corrosion tests, it was determined that the oxidized-coated sample showed the best condition compared to the other samples in EIS analyzes.

This study focuses on the comparison of structural, morphological, mechanical, tribological and electrochemical properties of TiO2 films fabricated on Cp-Ti, Ti6Al4V and Ti45Nb alloys, which are widely used in different industries. For this purpose, TiO2 films were grown on Cp-Ti, Ti6Al4V and Ti45Nb materials by anodization method. Structural, morphological and mechanical properties of the samples were determined using XRD, SEM, Micro Raman, contact angle, surface roughness and micro hardness devices. Afterwards, the samples were subjected to wear and corrosion tests using a pin-on-disc wear device and a corrosion device, respectively. Wear tests were carried out in both dry and liquid environments. In electrochemical corrosion tests, Ringer's solution was used and open circuit potential (OCP) and electrochemical polarization analyzes were performed. According to the results of XRD and Raman analyses, it was determined that TiO2 films were successfully grown on the surface of the samples. Additionally, it was observed that these films were in Rutile and Anatase phases and their peak intensities increased with increasing anodization time. While the thickest films were obtained from Ti45Nb samples, the thinnest films were obtained from Cp-Ti samples. As a result of the increase in surface roughness with anodization, surface wettability increased in all samples. It was seen that electrical resistance of the materials was highly effective on the film thickness, surface roughness and surface structures. Wear coefficients decreased in all samples for both dry and liquid wear conditions due to the increased surface hardness and anodic film thickness and the lowest wear coefficients were obtained from the Ti45Nb sample. Corrosion performance of the samples increased with anodization because TiO2 films acted as protective layers on surface of materials.

This comprehensive study investigates the corrosion and biocompatibility performances of boron-doped TiO2 nanotubes (TNT) synthesized on Ti6Al4V alloy produced by the selective laser melting (SLM) process. Structural analysis reveals a consistent reduction in nanotube diameter across varying boron doping levels (0.05 - 2 M boric acid doping), with B4-TNT exhibiting the smallest diameter at 190 nm. Boron incorporation induces phase transformation and decreases in diameter of nanotubes, influencing the material's structural properties. Corrosion resistance assessments indicate a significant enhancement, with B4-TNT demonstrating the highest polarization resistance (Rt = 2849.03 k Omega.cm2). The observed improvements are attributed to the combination of reduced nanotube diameter, altered phase structure, and increased polarization resistance, collectively contributing to enhanced corrosion resistance. Biocompatibility experiments conducted with human fibroblast cells (HDFa) reveal that B-doped TNTs foster increased cell viability compared to undoped TNT and uncoated alloy surfaces. These findings underscore the potential of boron doping as a strategic approach to improve corrosion resistance and enhance the biocompatibility of Ti6Al4V implants. This study provides valuable insights for advancing materials in biomedical applications with improved structural, corrosion-resistant, and biocompatible properties.

In this study, the electrochemical corrosion properties of commercial pure titanium (Cp-Ti) samples produced by additive manufacturing and forging were compared by plasma oxidizing. Plasma oxidizing processes were carried out at temperatures of 650 degrees C and 750 degrees C for 1 h and 4 h. Electrochemical corrosion experiments were carried out in Simulated Body Fluid (SBF) using open circuit potential, cyclic potentiodynamic polarization and electrochemical impedance spectroscopy methods. It was found that the coating thickness of F 750 degrees C-4 h and S 750 degrees C-4 h samples was the highest. The corrosion resistance of the samples produced by additive manufacturing is lower than that produced by forging due to the Lack of fusion (LOF) effect. The barrier layer developed by the plasma oxidizing process significantly improved the corrosion performance of additive manufacturing by reducing the LOF effect. The minimum corrosion rate was obtained at S 750 degrees-4 h. While the total material loss due to corrosion was the lowest on this surface, the last corroded surface was F 750 degrees-4 h. The maximum resistance was observed on the plasma oxidized surfaces for the group produced by forging.

Textured surfaces were used to increase the electrochemical corrosion resistance of the laser powder bed fusion, corrosion performance, DC corrosion and electrochemical impedance spectroscopy techniques were examined. Corrosion resistance could be optimized as a result of changing the surface energy on modified surfaces and eliminating selective laser melting (SLM)-induced morphological discontinuities. The corrosion resistance of optimum textured surfaces is higher than that of forged samples. Results close to texture-free surface performance were obtained on surfaces where texture density reached maximum. Increasing texture weakened the corrosion resistance. Thus the best corrosion resistance; i corr = 156 nA/cm 2 with E corr = -327 mV observed at 5CR. Material losses are 49.40 mpy x 10 -3 for 5CR, 63.48 mpy x 10 -3 for 5SQ, 382.60 mpy x 10 -3 for 15CR, 63.33 mpy x 10 -3 for 15SQ, 394.6 mpy x 10 -3 for 25CR and 174.80 mpy x 10 -3 for 25SQ, respectively. The highest performance in terms of material losses was found to be 5CR. No significant change in the context of texture geometry was observed in the SEM images. According to quantitative evaluation in electrochemical corrosion tests, the differences are quite close to each other.

& beta;-Titanium alloys have become increasingly popular as biomaterials because of their low modulus of elasticity and superior corrosion properties in recent years. & beta;-titanium alloy containing niobium is also a biocompatible and non-toxic material. Among & beta;-Ti alloys, Ti45Nb is one of the most remarkable alloys for its superior properties as a biomaterial. This alloy has superior properties due to low elasticity modulus and non-toxic elements, but its surface properties are inadequate for biomaterial applications. Therefore, various surface treatments are applied to improve the surface properties of these alloys. In this study, an oxide film layer was formed on the Ti45Nb surface under different potential conditions by the anodizing method. The effects of these factors on friction, wear, and contact angle measurements were investigated. The structural properties of the oxide film coated samples were analyzed with XRD and their surfaces and cross-sectional images were observed by SEM. Also, the surface roughness and nanoindentation tests were performed. In this regard, it was determined that oxide film thickness, surface roughness and hardness increased with the increase of anodization potential. The contact angle of the samples decreased with the increase in the anodization potential and the surface tension of the materials increased. The highest nanohardness of about 4.19 GPa was obtained from 150 TA samples. The elasticity modulus of the untreated sample was about 63 GPa, while the anodized samples ranged from an average of 31 to 83 GPa. The wear results revealed that the anodization process improved the wear resistance of the Ti45Nb alloy. As a result, the sample anodized at 200 V for 30 min exhibited optimum surface roughness, morphology and high wear resistance.

Protective films with excellent tribological performance and good corrosion resistance are needed in general because titanium implants are used in aggressive environments and always suffer from severe wear and corrosion. In this study, TiO 2 –SiO 2 multilayer films were deposited with different numbers of bilayers (2, 4, and 8) on β-type Ti45Nb alloy substrates by physical vapour deposition. The influence of number of bilayers on microstructure, wettability, mechanical features, tribological performance and electrochemical behaviour of TiO 2 –SiO 2 multilayer films were comparatively observed via XRD, XPS, SEM, AFM, nanoindentation tester, contact angle measurement system, reciprocating tribo-tester, and electrochemical corrosion media. The surface hardness, wear and corrosion resistance values of multilayer film-coated substrates were higher than the untreated substrate values. These properties and adhesion resistance and hydrophobicity of coated samples also increased with increase in number of bilayers due to the smaller grain size, increased layered interfaces and high structural density.

This study aims to investigate the effects of duplex surface treatment consisting of plasma nitriding and DLC coating on the fatigue properties of Ti6A4V alloy. For this investigation, Ti6Al4V samples were plasma nitrided at 650 degrees C, 700 degrees C and 750 degrees C for 1, 2 and 4 h and then DLC films were produced on the plasma nitrided samples. The structural, mechanical and morphological features of the samples were characterized by XRD, SEM, micro hardness tester and scratch tester. Fatigue tests were performed on the samples by using stress life method. On the surface and sub-surface of the samples, a compound layer and a diffusion zone were formed by plasma nitriding, respectively and XRD results revealed that these layers consisted of Ti2N and TiN phases. The raising process time and temperature caused to increase the thickness of these layers and they also increased the surface hardness of the samples. On the other hand, DLC coated samples exhibited more surface hardness than untreated and all the plasma nitrided samples. Fatigue analyses revealed that plasma nitriding reduced the fatigue strength of the material in all process conditions. Although plasma nitriding formed hard surface and sub-surface layers, the brittle structure of the layers and the great difference of elastic modulus between the substrate and nitride layers caused to decrease the fatigue strength of the material. Although DLC coating increased the fatigue strength of untreated and plasma nitrided samples at 650 degrees C for 1 h, 700 degrees C and 750 degrees C for 4 h), the fatigue strength of duplex treated samples (plasma nitrided at 650 degrees C for 1 h, 700 degrees C and 750 degrees C for 4 h and DLC coated) was lower than the fatigue strength of untreated material, similar to only plasma nitrided materials. This showed that the fatigue strength of duplex treated Ti6Al4V was controlled by plasma nitriding.

Titanium is an important biomaterial, but its wear resistance is insufficient compared to other metallic biomaterials. Another problem with the use of implants is the "stress-shielding" effect caused by the difference in elastic modulus between the implant and the bone. To reduce this effect, the use of implant materials with modulus of elasticity close to that of bone has become prominent.In this study, (α+β)-type Ti6Al7Nb, which is widely used in the manufacture of orthopedic implants, and (β)-type Ti45Nb alloy, which has a lower elastic modulus, were oxidized at 600°C, 700°C, and 800°C for 1 and 4 hours in a DC glow discharge oxygen plasma environment. It was found that rutile TiO2 formed predominantly on the surfaces The modified layer thickness increased with increasing temperature and process time, and the wear rates decreased significantly for both alloys. Plasma oxidation generally improved the tribocorrosion properties as the corrosion products reduced wear. Potential toxic effects occurred in some samples treated at high temperatures. No genotoxic effects were observed. For both alloys, the best results were obtained by oxidation at low temperatures and short times, and it was concluded that alloy Ti45Nb can be used as a biomaterial.

Commercial pure titanium (Cp-Ti) is widely used in many industrial and biomedical fields. However, depending on the conditions of use of Cp-Ti, it exhibits low wear and corrosion resistance, thus reducing its service life. Therefore, in this study, the cuticle of the Japanese jewel beetle (Chrysochroa rajah) was morphologically examined and duplex coatings were produced by dip coating technique on Cp-Ti to provide protection against wear and corrosion by imitating the layered structure of the Chrysochroa rajah cuticle. Duplex coated surfaces were obtained by dip coating technique with chitin as the first layer and TiO2, SiC and h-BN layers as the second layer, respectively. Electrochemical corrosion properties were investigated under Simulated Body Fluid (SBF) solution. In electrochemical corrosion tests, open circuit potential (OCP), electrochemical polarization and electrochemical impedance spectroscopy (EIS) analysis were performed. Wear tests were performed in dry and SBF solution, and tribocorrosion tests were performed in SBF solution. The chitin + h-BN duplex coated surface has the highest corrosion potential (Ecorr) of-14 mV and the lowest corrosion current density (icorr) of 1.060 x 10-9 A cm-2. In addition, chitin + h-BN duplex coated surface has the highest corrosion resistance among duplex coated surfaces with corrosion rate of 4.601 x 10-4 mpy. In the wear test results, the lowest wear rate was 0.12 +/- 0.011 x 10-3 mm3/Nm in dry environment and 0.28 +/- 0.017 x 10-3 mm3/Nm in SBF solution on chitin + TiO2 duplex coated surface. In addition, the highest surface hardness was obtained as 4 +/- 0.28 GPa on the chitin + TiO2 duplex coated surface. As a result of the tribocorrosion tests performed in SBF solution, the highest resistance was obtained on the chitin + TiO2 duplex coated surface. The chitin layer exhibited low corrosion, wear and tribocorrosion performance. Due to the effect of different electrical charge transfer and different hardness of organic and ceramic powders used in coatings, the coated surfaces improved the electrochemical, abrasion and tribocorrosion properties of Cp-Ti.

In this study, commercial titanium (Cp-Ti) was coated with a UV-curable film to improve the wearing and tribocorrosion performance of Cp-Ti. Wear tests were carried out under dry and simulated body fluid (SBF) test environments, and tribocorrosion tests were also performed in SBF. In tribocorrosion tests, a reciprocating test device coupled with open circuit potential and potentiodynamic polarization test monitoring system was used. SEM investigations showed that a polymeric film with a layer thickness of about 3-4 mu m was deposited on Cp-Ti. It was also found that the Si element in the film considerably increased the hardness and improved the wear performance. According to tribocorrosion test results, the corrosion mechanism has significantly increased the wear rates. The wear resistance of the Cp-Ti surface was markedly enhanced by UV-curable treatment.

AZ31 alloy is a widely used material in biomedical applications. It is an alternative alloy for temporary im-plantation due to its low weight and superior biocompatibility. However, surface properties such as wear and corrosion are quite weak compared to other metallic biomaterials. It is extremely important to improve the surface properties, as these two mechanisms cause very serious material damage on Mg alloys separately or synergistically. In this context, oxidation processes are carried out with the plasma electrolytic oxidation (PEO) method, which provides very successful adhesion in alloys such as AZ31. In this study, the tribocorrosion per-formance of the films produced by doping Cu, B and Zn elements using PEO was investigated. The simultaneous effects of corrosion and wear mechanisms on surfaces were investigated with experiments carried out in artificial body fluid (SBF). It was concluded that the porous oxide films undergo morphological changes with the effect of additive elements, this change in morphology has a barrier effect, especially against corrosion attacks, and the improved corrosion resistance also improves the wear performance. According to the OCP measurements made under wear, the surface that showed the most noble behavior was Zn-doped (-0.71 V). A similar behavior can be mentioned for the wear test carried out together with the potentiodynamic polarization test. It minimized the Zn current density value in the structure (2.3 x 10-6 A/cm2).