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In this study, the development of a novel composite coating for Ti-6Al-4V alloy dental implants, combining wollastonite (CaSiO 3) and forsterite (Mg 2 SiO 4) with varying ratios of manganese (Mn) addition was investigated. The coating was designed to enhance osseointegration while addressing concerns about calcium (Ca2+) dissolution from wollastonite over time. Ti-6Al-4V alloy substrates were first treated with plasma electrolytic oxidation (PEO) to improve surface functionalization. The composite coating was then synthesized using the sol-gel method and applied via spin coating. The effects of Mn addition on surface characteristics were evaluated using FE-SEM, AFM, XRD, wettability tests, scratch tests, corrosion (PDP and EIS) tests, and in vitro testing. The results showed that Mn incorporation significantly influenced the coating's morphology, mechanical properties, corrosion resistance, and bioactivity. Among the tested concentrations, the 10 % Mn coating exhibited the best overall performance, achieving a balance of high corrosion resistance, enhanced mechanical stability, and superior bioactivity. The synergistic action of Mg2+, Mn2+, and Si4+ within the coating created an ideal environment for rapid and extensive hydroxyapatite (HA) growth. While higher Mn levels further promoted HA formation, they also maintained acceptable surface stability, demonstrating the potential for broader applications. The combined effects of wollastonite's rapid HA formation, forsterite's controlled dissolution, and Mn's additional nucleation sites make these coatings highly promising for applications requiring strong, long-lasting bone-bonding properties. • Wollastonite-forsterite coatings on pore-formed Ti alloy via spin coating were researched. • Coatings with increased Mn content in Mg (2 − x) Mn x SiO 4 low hydrophilicity and wettability • Content of 10 % Mn provided the optimal balance of properties with improved bioactivity. • Content of 50 % Mn had low mechanical properties, whereas, high biocompatibility. [ABSTRACT FROM AUTHOR]

This comprehensive study conducts a systematic assessment of the mechanical and corrosion properties of titanium-based dental implant materials after plasma electrolytic oxidation (PEO) treatment in a solution containing Ca and P ions. Pure titanium, cold-worked pure titanium, and Ti-6Al-4V alloy underwent PEO treatment to enhance their surface characteristics. Through systematic analysis, we explore the wettability, surface roughness, hardness, elastic modulus, and corrosion resistance of PEO-treated titanium-based dental implant materials. FESEM and XRD were also done to scrutinize the crystalline structure and microstructural features before and after PEO treatment and corrosion testing. The results of this study indicate that the incorporation of PEO treatment in Ti-based materials has increased their properties as an improved biomaterial. Among all groups, Ti-6Al-4V + PEO was found to hold enhanced mechanical strength and corrosion resistance. These findings provide crucial insights for the advancement of implants through PEO treatment, suggesting that PEO treatment can optimize clinical outcomes in dental implant applications. • Plasma electrolytic oxidation (PEO) coatings on mechanically cold-worked titanium were researched. • Morphology of PEO coating on Ti alloy showed numerous large volcanic-like porous eruptions. • Surface of cold-worked PEO coating presented clusters of nano-scaled pores with an anatase phase. • PEO-treated Ti surface improved corrosion resistance, wettability, roughness, and mechanical properties. [ABSTRACT FROM AUTHOR]

In this study, the corrosion behaviors of bioactive element coatings on plasma electrolytic oxidation (PEO)-treated Ti-6Al-4V alloys were researched using various instruments for measurement of coated elements from PEO-treated surface in the solution of simulated fluid. For this research, Ti-6Al-4V ELI disks were prepared as the substrates for PEO treatment. PEO treatment was carried out using pulsed DC power supply at 280 V for 3 min in electrolytes containing bioactive ions such as silicon, zinc, manganese, magnesium, strontium, calcium, and phosphorus. To analyze the electrochemical properties of the PEO film as a function of added ions in the electrolyte, potentiodynamic and AC impedance tests were performed using a potentiostat in 0.9% NaCl solution. The alloy surface after performing a corrosion test of the PEO-treated specimen on the Ti-6Al-4V alloy was observed using a field-emission scanning microscope, energy dispersive X-ray spectrometer, and X-ray diffractometer (XRD). When a bioactive element was added during the PEO process, the pore size decreased and a precipitate containing a high Mn content was formed around the pores. The XRD results of the PEO-treated surface with bioactive elements showed that the anatase and HA phase contents increased while the Ti peak intensity decreased. When Mn was added to the electrolyte, a second anodic peak appeared, and the precipitates on the surface and pore edges were dissolved in the 0.9% NaCl solution. The results of AC impedance tests revealed a decrease in the polarization resistance of the PEO-treated surface. • Corrosion behaviors of PEO-treated Ti-6Al-4V alloy in bioactive ions were researched. • If bioactive ion was added in the PEO process, the pore size decreased and Mn precipitate was formed. • In the case of PEO-treated surface with bioactive ion, anatase increased and HA phase increased. • In case of PEO-treated surface with Mn ion, a second peak appeared and precipitates were formed. • From AC impedance test results, the PEO-treated surface showed decreased polarization resistance. [ABSTRACT FROM AUTHOR]

Abstract The surface morphology and cell behavior of a Zn-coated Ti-6Al-4V alloy fabricated by radio frequency (RF) sputtering after plasma electrolytic oxidation (PEO) treatment were studied using several experimental instruments. The PEO of the Ti-6Al-4V alloy was performed in electrolytes followed by RF magnetron sputtering of the Zn coating on the PEO-treated Ti-6Al-4V alloy. The effects of the biological changes on different conditions were investigated using MC3T3-E1 cells. The morphology and structure were examined by using field-emission scanning electron microscopy, and an elemental analysis was performed using energy-dispersive X-ray spectroscopy and a thin film X-ray diffractometer. The surface of the oxide films after PEO coating demonstrated the formation of many micro-pores with a uniform distribution. The RF-sputtered surface exhibited small particles covered with droplet shapes on the pores inside and on the surface of the films. As the sputtering time increased, the [Ca + Zn]/P ratio of the Zn coating on the PEO-treated Ti-6Al-4V alloy increased. Moreover, the amorphous phase increased and crystal phase was decreased with increasing sputtering time. The corrosion rate on Zn coated surface increased as sputtering time increased. Following the MC3T3 cell culture, filopodia was attached to the inside of the pores in the 1 min/Zn-coated sample with the micro/nano-shapes of Ca/P. As a result of the MTT analysis using the MC3TC-E1 cell, the 1 min/Zn-coated sample presented a higher cell proliferation rate than the PEO-treated Ti-6Al-4V alloy. Highlights • Surface morphology and cell behavior of Zn-coated Ti-6Al-4V alloy by RF sputtering after PEO treatment were studied. • As the sputtering time increased, the circular particles of Zn coatings on the Ti-6Al-4V alloy increased. • The amorphous phase increased, whereas crystal phase was decreased, as the sputtering time increased. • The corrosion rate on Zn coated surface increased as sputtering time increased. • From the cell culture test, Zn coatings for 1 min showed higher cell proliferation rate. [ABSTRACT FROM AUTHOR]

The electrochemical characteristics of Ti-6Al-4V after plasma electrolytic oxidation (PEO) in solutions containing Ca, P, and Zn ions were studied using various experimental techniques. A Ti-6Al-4V ELI disk was used as a substrate for plasma electrolytic oxidation. A pulsed DC power supply was used to apply a potential of 280 V in the electrolyte for 3 min. To analyze the electrochemical properties of the PEO film as a function of the Zn content, potentiodynamic and AC impedance tests were carried out with a potentiostat (Model 2273, EG&G Co., USA) using a 0.9% NaCl solution. To examine the bioactivity, the PEO films formed on the specimens and the untreated Ti-6Al-4V specimens were immersed in a simulated body fluid (SBF) for 12 h. The PEO-treated and SBF-immersed surfaces were observed by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and attenuated total reflectance Fourier transform infrared spectroscopy. The number of pores in the PEO films increased, whereas the pore size decreased slightly, as the Zn ion concentration increased. The corrosion potential of the PEO-treated films decreased, while the corrosion current density increased slightly, as the Zn content increased. As shown by the Nyquist plots, the semicircular region in the profile of the Ti-6Al-4V specimens increased compared to that of the other specimens. The films obtained after PEO treatment in the solution containing Zn showed Warburg impedance characteristics. Bone-like apatite was well-formed in specimens of PEO films treated in solutions containing Zn ions at concentrations of 0, 5, and 10 mM%. However, formation of the bone-like apatite decreased in specimens of the PEO films treated in a solution containing Zn ions at a concentration of 20 mM%. [ABSTRACT FROM AUTHOR]

In this study, the effects of Hf content on the nanotubular structure of Ti-29Nb-xHf ternary alloys were investigated. The Ti-29Nb-xHf ternary alloys had Hf concentrations between 0 wt.% and 15 wt.% and were manufactured using a vacuum arc-melting furnace. Formation of a nanotube structure on these alloys was achieved by an electrochemical method in a 1 M H 3 PO 4 + 0.8 wt.% NaF electrolyte solution. The microstructures of the Ti-29Nb-xHf alloys changed from a needle-like structure to an equiaxed structure with increasing Hf content. The surface characteristics were analyzed by field-emission scanning electron microscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and a wettability test. The Ti-29Nb-xHf alloys had an equiaxed grain structure with α″ + β phases, and the α″ phase disappeared with an increase in the Hf content. The Ti-29Nb-15Hf alloy showed higher intensity β-phase peaks in the XRD patterns compared to Ti-29Nb-3Hf and Ti-29Nb-7Hf alloys. The average length of the nanotubes increased and the nanotubes became highly ordered as the Hf content increased. The contact angles of the surface with the nanotubes were lower than those of surfaces without nanotubes. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the bioactivity of porous TiO2 surfaces formed on titanium in mixed electrolyte by spark anodization was investigated both in vitro and in vivo. To fabricate geometric micropores on titanium for implant applications, plasma electrolytic oxidation (PEO) was carried out in an electrolyte consisting of 1.5M H2SO4 +0.7M H3PO4 +0.4M H2O2. The surface characteristics of the microporous Ti layer were investigated by FE-SEM, EDS, and XPS, and the bioactivity of PEO surfaces was assessed by MC3T3-E1 cell culture, cell viability, ALP activity, and in vivo immune response. A gradual increase of the spark width and the voltage applied caused pitting that leads to the formation of circular pores distributed over the entire surface. The fraction of the surface area occupied by pores increased as the anodizing time increased. The microporous TiO2 surface provided higher cell adhesion, proliferation and viability compared to the metallic titanium control group. Cells cultured on the surface of geometrical microporosity demonstrated higher ALP activity. Hypodermic tissue and connective tissue were well attached on anodized surface after 10 and 20min. In particular, on the micropore-formed surface after 30min, an abundant amount of hypodermic and connective tissue was observed among the adjacent micropores. [Copyright &y& Elsevier]

Abstract: In this study, the tribological and thermal properties of TiAlCN coatings were investigated to evaluate their feasibility in automobile applications. TiAlCN coatings with carbon compositions between 25 and 65at.% were prepared by inductively coupled plasma (ICP) assisted sputtering and were annealed at 400, 500, and 600°C in air. The structures and compositions of the coatings were studied by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and Auger electron spectroscopy. The hardness and tribological performance were evaluated by micro-indentation and ball-on disk tests. The wear rates were calculated using a non-contact 3D surface profiler. At a carbon composition>50at.%, the coatings featured a mixture of amorphous and crystalline phases and exhibited superior tribological performance compared to that of commercialized carbon or nitride coatings. Raman spectroscopy revealed that even when the amorphous carbon phase has a relatively high sp2 to sp3 ratio, there are sufficient amounts of TiAlN grains to support the hardness in the coatings. The coating hardness decreased slightly after high-temperature annealing due to graphitization in the amorphous carbon phase, however, the friction coefficients and wear rates were reduced with the annealing temperature. [Copyright &y& Elsevier]

Abstract: To achieve excellent biocompatibility of metal-based implants, hydroxyapatite thin film coatings on nanotube-formed Ti–35Nb–10Zr alloys after femtosecond laser texturing have been investigated. Three groups of samples were prepared: (1) microtextured surfaces using femtosecond (FS) laser, (2) nanotube surfaces formed by anodization, and (3) hydroxyapatite coatings vapor-deposited by a physical electron beam method on the Ti–35Nb–10Zr ternary alloy. The surface morphology of the Ti–35Nb–10Zr alloys was examined by x-ray diffractometry, field-emission scanning electron microscopy, and energy-dispersive x-ray spectroscopy. To investigate ion release, potentiodynamic polarization testing was carried out in 0.9%NaCl solution, and wettability tests and MG 63 osteoblast-like cell culture studies were performed on the surfaces of the three groups to evaluate contact angle and cell growth morphology, respectively. The Ti–35Nb–10Zr alloys exhibited the equiaxed β phase structure. The FS laser-treated Ti–35Nb–10Zr alloys showed circular traces with diameters of 28±1.5μm and hole separations of 50μm, and the nanotubes formed on the surfaces had diameters of 180±15nm and compositions consistent with TiO2, Nb2O5, and ZrO2. The nanotube structure showed anatase, rutile and β-titanium diffraction peaks, whereas the HA-coated surface on the nanotubes showed hydroxyapatite, anatase and rutile peaks. The HA coatings displayed the desired role of decreasing the metal ion release with a lower current density value, and the nanotubes and FS laser-treated surface showed wider passive regions compared to other surfaces. The HA-coated surface on the nanotubes after FS laser texturing showed the lowest contact angle compared with the other surfaces. From FE-SEM observations, cell attachment and spreading of MG 63cells showed significantly higher tendency for surfaces covered by HA coating and nanotubes. [Copyright &y& Elsevier]

In this study, to improve the material properties and biocompatibility of Ti alloys, Ti-xNb-2Ag-2Pt alloy was prepared by adding niobium (Nb), silver (Ag), and platinum (Pt). The surface was treated by anodization, and surface treated alloy was coated with HA, Mg, and Si through magnetron sputtering. Ti-xNb-2Ag-2Pt alloys were based on a Ti-2Ag-2Pt alloy, and the Nb content was changed to 10, 30, and 50 wt%. The nanotubes were formed by anodization in 1 M H 3 PO 4 and 0.8 wt% NaF electrolyte, following which the sample was coated by RF-and DC-magnetron sputtering using HA, Mg, and Si targets. The surface morphology and material properties of Ti-xNb-2Ag-2Pt alloys were analyzed by optical microscopy (OM), nano-indentation tests, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectrometer (EDS), and X-ray diffractometer (XRD). In the case of Ti-xNb-2Ag-2Pt alloys, the martensitic and needle-like structure decreased and the equiaxed structure increased with increasing Nb content. The elastic modulus of Ti-50Nb-2Ag-2Pt alloys was lower than that of Ti-10Nb-2Ag-2Pt alloys. As the Nb content increased, the shape of the nanotubes changed irregularly and nanotube diameter of Ti-xNb-2Ag-2Pt alloys decreased. Also, nanotube diameter after co-sputtered Mg and Si on HA coated surface decreased compared to only HA deposited nanotubes. • Magnesium, silicon, and hydroxyapatite deposition on the Ti-xNb-2Ag-2Pt alloy by co-sputtering were studied. • The microstructure of Ti-xNb-2Ag-2Pt alloys changed from α to β phase, as the Nb content increased. • The elastic modulus and indentation hardness of Ti-xNb-2Ag-2Pt alloys was lower than that of Ti-6Al-4V alloy. • The shape of the nanotubes changed irregularly, and nanotubes diameter decreased, as Nb content increased. • The size of the nanotube holes after Mg and Si deposition decreased compared to HA deposited nanotube. [ABSTRACT FROM AUTHOR]

This study examined the capability of plasma electrolytic oxidation (PEO) to fabricate an ideal implant porous material for bio-implant applications. For this purpose, the Ti-xNb binary alloys (x = 10, 30, and 50 wt.%) were treated via PEO using a DC power supply at a voltage was fixed to be 280 V for 180 s using an electrolyte composed of calcium acetate and calcium glycerophosphate. The structure of Ti-xNb alloys before PEO was altered from needle-like structure to an equiaxed structure with increasing the Nb content. After PEO, the high content of Nb element in the substrate led to an increase in the size and fraction of the micropores where a highly porous coating was fabricated on the sample with 50 wt.% Nb. This was attributed to the high plasma discharges developed at high current density conditions. The coating made on Ti-30Nb alloy exhibited a high ratio of Ca/P and higher corrosion resistance as compared to the counterparts formed on Ti-10Nb and Ti-50Nb alloys. The presence of anatase and Nb 2 O 5 together with ∼1.13 μm micropores in the coating made on Ti-50Nb alloy were the main factors responsible for the easy formation of hydroxyapatite during the soaking in a simulated body fluid solution. • An ideal implant porous material is successfully fabricated from Ti-30Nb alloy via PEO. • Effect of Nb content on the surface properties of Ti-xNb alloy coated via PEO is significant. • A protective bioactive coating is successfully obtained by PEO process of Ti-30Nb alloy. • Wettability of the PEO coatings was improved as compared to the bulk alloy surface. [ABSTRACT FROM AUTHOR]

In this study, OCP powder was used for mechanical coating on the plasma electrolytic oxidized (PEO) implant surface to improve bioactivity. PEO treatment was performed on the surface of the implant using a solution mixed with calcium acetate and calcium glycerophosphate, and creates porosity through a pulsed DC power supply. For compositional analysis, energy dispersive X-ray spectrometer analysis was employed to calculate OCP content and X-ray diffractometer analysis was used to confirm the crystal structure. Also, wettability, surface roughness, hardness, elastic modulus, and corrosion resistance testing were performed. Significantly, the reduction in OCP particle size decreased, and pore filling with OCP smaller particles increased as mechanical coating time increased from 0 to 12 h. Surface and cross-sectional morphology showed the presence of OCP on the substrate. Also, surface roughness, contact angles, hardness, and elastic modulus were reduced as mechanical coating time increased. Corrosion resistance was found to be the highest for mechanical OCP coating for 6 h surface treatment on the PEO-treated CW-Ti. • Mechanical octacalcium phosphate (OCP) coatings on plasma electrolytic oxidized (PEO) titanium were researched. • OCP particle size decreased and pore filling increased as mechanical coating (MC) time increased. • Surface and cross-sectional morphology showed the presence of OCP on the substrate. • Surface roughness, contact angles, hardness, and elastic modulus were reduced as MC time increased. • Corrosion resistance of sample surface improved by mechanical OCP coatings. [ABSTRACT FROM AUTHOR]

Abstract: In this study, photoelectrochemical analysis of bioactive material coated nanotubular surface of Ti–30Nb–xZr alloy has been investigated using a potentiostat and a Xenon lamp. Ternary Ti–30Nb–xZr(x=3, 15wt.%) alloys were prepared, and nanotube was formed using potentiostat in 1M H3PO4 +NaF(0.8wt.%). Hydroxyapatite (HA) was coated on nanotubular alloy by electron-beam physical vapor deposition (EB-PVD) method. The surface characteristics and photoelectrochemical behavior were investigated by FE-SEM, EDS, XRD and potentiostat. The microstructures of the Ti–30Nb–3Zr and Ti–30Nb–15Zr alloys showed an equiaxed grain structure with needle-like α phase in the β phase grains. The large nanotubes surrounded by smaller diameter nanotubes were formed with highly ordered surface on the Ti–30Nb–15Zr alloy. HA coated Ti–30Nb–15Zr surface has an irregular surface and flake-like particles with (211) and (112) crystalline planes. In the UV-irradiated Ti–30Nb–xZr alloy, the current density in the passive region was higher than that of non-UV-irradiated Ti–30Nb–xZr alloy, whereas for the nanotube surface the current density difference between UV-irradiated and non-UV-irradiated alloys was not significant. The Rp value of HA coated/nanotube surface under UV-irradiation was higher than that of the other surface. The phase angle of HA coated/nanotube surface was close to 60–70°. The study suggested that the photofunctionalization reaction strongly depends on the structure of oxide surface, crystallinity of hydroxyapatite and alloying elements. [Copyright &y& Elsevier]

The deposition of ultra-fine Pd/Ag/HAp nanoparticles onto TiO 2 nanotubes has been performed by an electrochemical method using a mixed electrolyte solution. Electrochemical deposition was carried out under constant voltage, and Pd/Ag/HAp nanoparticles were carefully added in the mixed electrolyte of 1.7 M (NH 4 )H 2 PO 4 + 0.4 M NH 4 F, which was slowly rotated by a magnetic stirrer on a hot plate in order to increase the diffusion rate of electrolyte ions. The electrochemical deposition behavior, chemical bonding state, and surface characteristics of the Pd/Ag/HAp nanoparticles have been investigated by FE-SEM, EDS, and XPS. The Pd/Ag/HAp nanoparticles were uniformly electrodeposited onto the whole top surface and around the tube walls, including the inner side and outer side, of the ultra-fine TiO 2 nanotubes. The ordered tubular structure was well-maintained without destruction during the electrochemical deposition process. With excessive activation up to a deposition time of 7200 s, continuous granular Pd/Ag/HAp nanoparticles gradually formed with a rough surface around the top of the TiO 2 nanotube layer. From the XPS and EDS analyses, Ti, Ca, P, Pd, and Ag were detected in the nanoparticles on the electrochemically deposited surfaces. The surface morphology after soaking in SBF exhibited hydroxyapatite-like precipitates, which consisted of the four elements Ti, O, Ca, and P, and having a Ca/P atomic ratio of 1.67. [ABSTRACT FROM AUTHOR]

Owing to the poor osseointegration capability, titanium implants may fail and are accompanied by bone resorption. As a result, the utilization of lasers for texturing the implant's surface has been deliberated as an indispensable and inventive approach for improved bone-implant contact by generating micro- and nano-scale surface topographies. Hence, the study aimed to examine the effect of femtosecond laser (Fs) and plasma electrolytic oxidation (PEO) coating on the surface characteristics of Ti-6Al-4V alloy with the evaluation of surface characterization, phase analysis, surface roughness, wettability, hardness, corrosion behavior, and adhesion potential. As per our study's result, it has been deduced that Fs texturing with and without PEO coating can be considered to be the innovative surface modification alternatives for biomaterials due to improved hydrophilicity, corrosion resistance, and surface roughness properties with hardness comparable to that of cortical bone thereby enhancing osseointegration capacity of bone to the implant. Also, a cell culture test was performed using MC3T3-E1 cells that indicated that Fs texturing and combined Fs texturing and PEO-coating can promote high cellular proliferation. • Plasma electrolytic oxidation(PEO) on femtosecond laser-treated Ti-6Al-4V was researched. • Fs-treated sample presented surface texturing with micro-columns or parallel lines with grooves. • PEO-treated sample on Fs-treated surface showed clusters of micro-pores and several elongated pores. • Fs-texture with and without PEO can be considered to be the innovative surface modification. [ABSTRACT FROM AUTHOR]

Abstract: In this study, surface characteristics of hydroxyapatite(HA) coated Ti-30Ta-xZr and Ti-30Nb-xZr alloys after nanotube formation have been investigated by EB-PVD, FE-SEM, XRD and potentiostat. The microstructures of the Ti-30Ta-xZr alloy had a needle-like morphology, and the thickness of this needle-like structure increased as the Zr content increased. The microstructures of the Ti-30Nb-xZr alloy had an equiaxed grain structure. The nanotubes were mainly nucleated and grown at β phase in case of Ti-30Ta-3Zr, but nanotubes were nucleated at α phase in case of Ti-30Ta-15Zr alloy. The corrosion resistance of alloy increased as Zr content increased, and nanotubular surface with highly ordered small and large tubes was high corrosion resistant. The corrosion resistance of HA coated alloys after nanotube formation was higher than that of the non-HA coated nanotubular alloy. [ABSTRACT FROM AUTHOR]

Abstract: A thin hydroxyapatite (HA) film was deposited on anodized titanium for the biocompatibility by RF sputtering method. The anodized titanium has improved its bioactivity further by the HA deposition on the anodized titanium surface. TiO2 layer with 0.2~0.5μm diameter pore size was formed on the Ti surface by anodization. HA film deposited surface showed that the pore size and number decreased compared with non-HA deposited surface. The corrosion resistance of HA deposited/anodized Ti was higher than that of the non-treatment Ti alloy in Hank''s solution, indicating better protective effect. From the results of cell culture using MTT assays, the best cell proliferation showed in HA deposited surface after anodization of Ti surfaces compared with another surface treatment. [Copyright &y& Elsevier]

Hydroxyapatite deposition on micropore-formed Ti-Ta-Nb alloys by plasma electrolytic oxidation for dental applications was investigated. Ti-35Ta-xNb alloys (x = 0 and 10 wt.%) were prepared with an arc-melting furnace. Micropores were formed on the Ti-35Ta-xNb alloys in 0.15 M calcium acetate monohydrate + 0.02 M calcium glycerophosphate at 280 V for 3 min. Hydroxyapatite deposition were carried out on the alloy surfaces using cyclic voltammetry in 2.5 mM Ca(NO 3 ) 2 ∙ 4H 2 O + 1.5 mM NH 4 H 2 PO 4 solution with various deposition cycles. Morphology and structure of the alloy surfaces and hydroxyapatite were investigated by field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The microstructure of Ti-35Ta-xNb alloys showed the α″ and β phases, and the XRD peak for the β phase increased with Nb content. For the non-NaOH treated surface, the morphology of HA deposited on Ti-35Ta-xNb alloys showed a plate-like shape, whereas the HA particle shape on the micropore-structured Ti-35Ta-xNb alloys was flower-like. The pore size and thickness of the surface barrier layer increased as the voltage increased. The fraction of rutile also increased as the applied potential increased. The anatase and rutile phases of TiO 2 can be controlled by applied voltage for enhanced biocompatibility. [ABSTRACT FROM AUTHOR]

Hydroxyapatite deposition on micropore-formed Ti-Ta-Nb alloys by plasma electrolytic oxidation for dental applications was investigated. Ti-35Ta-xNb alloys (x = 0 and 10 wt.%) were prepared with an arc-melting furnace. Micropores were formed on the Ti-35Ta-xNb alloys in 0.15 M calcium acetate monohydrate + 0.02 M calcium glycerophosphate at 280 V for 3 min. Hydroxyapatite deposition were carried out on the alloy surfaces using cyclic voltammetry in 2.5 mM Ca(NO 3 ) 2 ∙ 4H 2 O + 1.5 mM NH 4 H 2 PO 4 solution with various deposition cycles. Morphology and structure of the alloy surfaces and hydroxyapatite were investigated by field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The microstructure of Ti-35Ta-xNb alloys showed the α″ and β phases, and the XRD peak for the β phase increased with Nb content. For the non-NaOH treated surface, the morphology of HA deposited on Ti-35Ta-xNb alloys showed a plate-like shape, whereas the HA particle shape on the micropore-structured Ti-35Ta-xNb alloys was flower-like. The pore size and thickness of the surface barrier layer increased as the voltage increased. The fraction of rutile also increased as the applied potential increased. The anatase and rutile phases of TiO 2 can be controlled by applied voltage for enhanced biocompatibility. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the morphology change of HA films on highly ordered nanotubular Ti–Nb–Hf alloys as a function of electrochemical deposition cycle. The Ti–25Nb–xHf alloys were manufactured by vacuum arc-melting, heat treated for 12 h at 1000 °C, and water quenched. The HA deposition was carried out using a cyclic voltammetry method with a potential range from − 1.5 V to 0 V (vs. SCE) in Ca(NO 3 ) 2 ·4 H 2 O + NH 4 H 2 PO 4 at 80 °C ± 1 °C (number of cycles: 5, 10, 20, and 50). The morphology changes were observed by OM, FE-SEM, XRD, EDS and image analyses. The microstructures of the Ti–25Nb–xHf alloys were transformed from α″ phase to β phase, and from a needle-like structure to an equiaxed structure as the Hf content increased. The average length of the TiO 2 nanotubes increased, and the nanotubes became more highly ordered, as the Hf content increased. The fraction of the alloy surface area covered by the nanotubes decreased from 81% to 73% with increased Hf content. The nucleation of HA was initiated, and the HA precipitates subsequently agglomerated, at the nanotube interspace area for a low number of deposition cycles. The HA precipitates on the nanotube-formed Ti–Nb–Hf alloy surfaces exhibited a needle-like particle morphology, which had different shapes and larger sizes with an increasing number of deposition cycles. Based upon a scratch test, the adhesion of the deposited layer to the titanium alloy was similar for all samples, and a critical load of approximately 6.0 N was required to detach the layer. The HA-deposited surface after nanotube formation on the Ti–Nb–Hf alloys should provide improved cell proliferation at a higher rate than on the nanotubular and bulk titanium alloy surfaces. [ABSTRACT FROM AUTHOR]

The surface characteristics of hydroxyapatite coatings on nanotubular Ti–25Ta–xZr alloys prepared by electrochemical deposition for dental implants have been investigated using various methods. The Ti–25Ta–xZr alloys were prepared by an arc melting furnace, homogenized for 12 h at 1000 °C in an argon atmosphere, and then water-quenched. Nanotubular structures were formed by an electrochemical method in 1 M H 3 PO 4 electrolytes containing 0.8 wt.% NaF. Electrochemical deposition was carried out using a cyclic voltammetry method over a potential range of − 1.5 V to 0 V at 80 °C in a 5 mM Ca(NO 3 ) 2 + 3 mM NH 4 H 2 PO 4 solution. Surface characteristics were observed by optical microscopy, X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, contact angle goniometer, and image analyzer software. Microstructures of the Ti–25Ta–xZr alloys changed from α″ phase to β phase, and the phases changed in morphology from a needle-like to an equiaxed structure with increasing Zr content. The arrangement of nanotubes changed from an irregular distribution to a high level of ordering surrounded by smaller tubes, and the occupied percentage of pore wall surface decreased from 28% to 23%, as the Zr content increased. HA precipitates also changed in morphology from a plate or leaf-like shape to a needle or flower-like shape as the Zr content increased. [ABSTRACT FROM AUTHOR]

Bioactive element coatings on nano-mesh formed Ti-6Al-4V alloy surface using plasma electrolytic oxidation were studied. Ti-6Al-4V alloy was used for nano-mesh formation, which was carried out in 1 M H 3 PO 4 + 0.8 wt% NaF at 30 V for 1 h. For micro-pore formation, plasma electrolytic oxidation (PEO) treatment was performed in a solution containing bioactive ions at 280 V for 3 min. After that, surface and biological characteristics were investigated using FE-SEM, EDS, AFM, Scratch test, XRD, wettability test, and MC3T3–1 cell culture test. The nanotubes and nano-mesh were well formed in the α-phase compared to β-phase. The many micro-sized pores on PEO(5ion) samples were formed with circular and irregularly shaped pores and the circular precipitate with oxide thickness of 2.0– 3.0 μm. PEO(5ion) and PEO(Ca + P) samples consisted of anatase and HA phases, and the surface roughness of the PEO samples was higher than those of nanotube and nano-mesh formed surface, whereas, the contact angle of the PEO samples was lower than those of nanotube and nano-mesh formed surface. The adhesive strength of the PEO(5ion) films showed higher compared to PEO(Ca + P) sample. The number of cells on the modified surface and oxide layers increased with the surface roughness. The cell growth and proliferation on the PEO(5ion) films were higher than those of polished surface, the adhesion of cells is greatly improved on the nano-mesh surface. • Bioactive coatings on nano-mesh formed Ti alloy via plasma electrolytic oxidation were researched. • Nano-mesh was formed in the alpha phase, but not as well formed in the beta phase. • Surface roughness and wettability of the PEO samples was higher than those of nano-mesh formed surface. • The cell growth and proliferation on the PEO(5ion) films were higher than those of polished surface. [ABSTRACT FROM AUTHOR]

In this study, the plasma electrolytic oxidation (PEO) of Ti-25Nb- x Ta alloys in a solution containing Ca and P ions was investigated by using various experimental techniques. The Ti-25Nb- x Ta ternary alloys having Ta contents (x) of 0, 3, 7, and 15 wt% were fabricated by using pure Ti. The applied voltage and treatment time of PEO were 280 V and 3 min, respectively. Calcium acetate monohydrate [Ca(CH 3 COO) 2 ·H 2 O; 26.69 g/L] and calcium glycerophosphate (C 3 H 7 CaO 6 P; 4.29 g/L) were used as the electrolytes in the PEO. The surface and mechanical properties of the Ti-25Nb- x Ta alloys were analyzed by optical microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, nanoindentation, atomic force microscopy, and wettability measurements. With the increase in the Ta content, the Ti-25Nb- x Ta alloy exhibited martensitic and equiaxed structures, while its Vickers hardness and elastic modulus decreased. All PEO-treated samples exhibited porous surfaces with irregularly shaped pores. While the pore size of PEO-treated alloys decreased, the number of pores and thickness of the coating tended to increase with increasing Ta content. The PEO-treated alloys in the solution containing Ca and P ions exhibited surface roughnesses of 235–271 nm. The contact angle of the PEO-treated surface gradually decreased with the increase in Ta content. • In this study, the plasma electrolytic oxidation (PEO) of Ti–25Nb– x Ta alloys was investigated. • Ti–25Nb– x Ta alloy exhibited martensitic to equiaxed structures with Ta content, while elastic modulus decreased. • All PEO-treated samples exhibited porous surfaces and irregularly shaped pores. • The pore sizes of PEO-treated alloys decreased, while the number of pores increased with Ta content. • The contact angle of PEO-treated alloys gradually decreased with Ta content. [ABSTRACT FROM AUTHOR]

In this study, calcium silicate ceramic coatings on the plasma electrolytic oxidized Ti-6Al-4V alloy using the sol-gel method was researched by performing surface characterization, phase analysis, surface roughness, wettability, scratch test, hardness, and in vitro tests. For this research, the Ti-6Al-4V alloy surfaces underwent PEO treatment utilizing a pulsed DC power supply. Later, wollastonite sol, a critical component in this research, was formulated and coated on the PEO-treated specimens. Morphology of PEO coating on Ti alloy showed volcanic-like porous eruptions, while increased wollastonite-coated samples showed wollastonite grain formation and nanostructure formation. PEO W3 surface presented anatase, wollastonite, and Ti phases from XRD analysis, while after the in vitro test, displayed higher HA formation. Also, the PEO W3 surface offered adequate roughness (0.207 ± 0.034 μm), improved wettability (8.70 ± 3.19°), enhanced surface energy (71.9 mJ/m2), and comparable mechanical properties akin to that of cortical bone. Furthermore, the in vitro test showed increased apatite formation over the PEO W3 specimen's surface, indicating that increased wollastonite coating can be considered advantageous for enhanced bioactivity of dental implants and improved clinical outcomes. • Wollastonite spin coatings on plasma electrolytic oxidized Ti-6Al-4 V alloy(PEO Ti) was researched. • Morphology of wollastonite-coated PEO-Ti alloy showed small grain and nanostructure formation. • Apatite formation over the highly wollastonite-coated PEO surface showed after In vitro test. • Wollastonite-coated PEO surface offered improved wettability, roughness, and mechanical properties. [ABSTRACT FROM AUTHOR]

This study examined the effects of TiN (titanium nitride) and WC (tungsten carbide) coatings on the fatigue characteristics of dental implants using a sinusoidal cyclic loading machine under load between 42–420N and 58–580N according to the ISO 14801. In this study, an abutment screw was coated with a TiN and WC film by EB-PVD and sputtering, respectively. For the fatigue test, the implant fixture and abutment were tightened to a torque 32Ncm using a digital torque gauge with 0.1Ncm accuracy. Field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) were used to observe the coated surface and fracture surface of the abutment screw. The uncoated abutment screws contained scratches caused by the mechanical process, whereas the TiN and WC coated screws showed a smooth surface at the screw thread and screw valley. The mean fatigue life of the uncoated, TiN coated, and WC coated abutment screw at 420N was 5.8×105, 8.2×105 and 106 cycles, respectively. At 580N, the mean fatigue life of the uncoated, TiN coated and WC coated abutment screw was 2.1×104, 4.1×104 and 2.3×104 cycles, respectively. The uncoated abutment screw showed the beach mark and fatigue striation. On the other hand, in the case of TiN and WC coated abutment screws, the semi-cleavage fracture and ductile fracture appeared at 420N. Semi-cleavage fracture and massive fatigue striation with a step of 0.5μm/cycle were observed in TiN coated abutment screw, whereas a minute slip band was noted and the interval of fatigue striation increased to several μm/cycle in the WC coated screw at 580N. [ABSTRACT FROM AUTHOR]

Abstract: The AC impedance behavior of silicon-hydroxyapatite doped film on the Ti–35Nb–xZr alloy by EB-PVD method was investigated in this study. The Si–HA composite coating layers were formed from Si of 0.8wt.% with HA by EB-PVD method. The surface characteristics were analyzed by FE-SEM, EDS, and XRD. The AC impedance test was performed the frequency range from 10mHz to 100kHz in 0.9wt.% NaCl solution at 36.5±1°C. The Ti–35Nb–10Zr alloy shows an equiaxed β-phase microstructure. HA‐coated surface of Ti–35Nb–10Zr alloy showed the small droplets and the chemical composition of HA‐coated surface consisted of Ca, P, Ti, Nb, and Zr with Ca/P ratio of 1.67. The surface of Si–HA‐coated Ti–35Nb–10Zr alloy showed rougher morphologies after heat treatment than as-surface with the coated thickness around 100nm. The Si–HA‐coated surface showed hydroxyapatite, calcium phosphate silicate, and β-Ti peaks. From the current density–time curves at constant 300mV, the current density of HA and Si–HA‐coated surface decreased with time, Especially, Si–HA‐coated surface showed the lower than HA‐coated and non-coated surfaces with time due stable film formation. From these results, Si–HA layer showed the high polarization resistance compared to other samples. Si–HA had a lager semicircle of Nyquist curve and increased in the order of non-coating, HA coating, and Si–HA coating. Si–HA‐coated surface showed a good corrosion resistance than HA single‐coated and non-coated surface. [Copyright &y& Elsevier]