Search Results (937)

This work investigates the NiTi shape memory alloys fabricated via laser powder-directed energy deposition (LP-DED). The properties of NiTi alloys produced by powder metallurgy or additive manufacturing routes are strongly influenced by the type of feedstock material employed. Two powder feedstocks were used for DED fabrication: a blended mixture of elemental nickel and titanium powders with a nominal chemical composition of Ni56Ti44 (wt.%) and a pre-alloyed NiTi powder containing 55.75 wt.% Ni. Samples fabricated from both types of powders were subjected to microstructural characterization, phase composition analysis, and mechanical and corrosion testing. It was found that DED processing on a non-preheated CP-Ti substrate is prone to warping and that samples deposited from the elemental Ni and Ti powder mixture exhibited pronounced inhomogeneity of microstructure and mechanical properties along the build direction, accompanied by the formation of the Ti₂Ni secondary phase. The absence of a superelastic plateau was observed in the corresponding stress–strain response. On the contrary, the samples deposited from the pre-alloyed NiTi powder exhibited a microstructure composed of B2 and B19′ phases and already demonstrated a clear superelastic response in the as-built condition during tensile loading. Based on the tensile test results, this NiTi material was used only for superelasticity testing. The superelastic behavior was further enhanced by post-deposition heat treatment, which significantly increased the recovery rate from 53% to 89%. Full article

Seawater electrolysis offers a promising route for sustainable hydrogen production in coastal areas, leveraging solar energy while reducing freshwater consumption. Yet, chloride-induced corrosion severely limits conventional electrodes such as titanium, which depend on passive titanium dioxide films and display minimal hydrogen evolution reaction activity (|i₀,H₂| ≈ 0.001–0.01 A/m²). Here, we report for the first time the use of copper-based coordination compounds—a triazole-derived polymer (CC_Cu) and a Prussian Blue Analogue (CuHCF)—as dual-function electrodes combining corrosion resistance with electrocatalytic activity. Structural integrity was verified by FTIR, TGA, XRD, and SEM/EDS analyses. Electrochemical tests in 0.5 M NaCl, interpreted using mixed potential theory, revealed corrosion potentials (E_corr) of −40 mV versus Standard Hydrogen Electrode (CuHCF) and −23 mV versus Standard Hydrogen Electrode (CC_Cu), and corrosion current densities of 0.259 and 0.379 A/m², respectively. Both exhibited hydrogen evolution reaction exchange current densities significantly higher than titanium (0.019 A/m² for CuHCF and 0.062 A/m² for CC_Cu). CuHCF achieved a Tafel slope of 222 mV/dec, comparable to NiMoP alloys and carbon steel. Complementary density functional theory calculations elucidated how metal–ligand interactions and electronic redistribution govern both catalytic performance and degradation. These findings introduce a new concept of semi-electrocatalysts, where copper coordination compounds act as structurally adaptive, low-cost materials bridging corrosion resistance and hydrogen evolution in seawater systems. Full article

This paper analyzes the influence of two milling tools with identical geometric features, coated with a titanium diboride (borox) coating and a polished coating, on the quality of the machined surface of a workpiece made of aluminum alloy EN AW-7075. Using the finite element method (FEM), stresses and deformations on the blade of the two tools were analyzed. The obtained stress and deformation values on the cutting edge of the tool coated with borox coating are higher, compared to the tool with polished coating. The tool coated with borox coating had a more favorable effect on the surface quality of the workpiece compared to the tool coated with a polished coating. In terms of corrosion resistance, the tool with a borox coating is more resistant than the tool with a polished coating. Therefore, maintenance of the tool with a borox coating is cheaper but the cost of production is higher. Full article

Titanium (Ti) and its alloys are widely used in biomedical applications due to their biocompatibility and corrosion resistance; however, surface modifications are required to enhance biological functionality. Surface functionalization using natural biomolecules has emerged as a promising strategy to improve early cell–surface interactions and biocompatibility of implant materials. In this study, Ti6Al4V alloy surfaces were biofunctionalized using Spirulina platensis (S. platensis) biomass and protein extract to evaluate morphological, chemical, and biological effects. The functionalization process involved activation with piranha solution, silanization with 3-aminopropyltriethoxysilane (APTES), and subsequent biomolecule immobilization. Surface characterization by scanning electron microscopy (SEM), inductively coupled plasma mass spectrometry (ICP-MS), energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR) confirmed the successful incorporation of microalgal components, including nitrogen-, phosphorus-, and oxygen-rich organic groups. Biomass-functionalized surfaces exhibited higher phosphorus and oxygen content, while protein-coated surfaces showed nitrogen-enrich chemical signatures, reflecting the distinct molecular compositions of the immobilized biomolecules. Cell adhesion assays demonstrated enhanced early cell attachment on biofunctionalized surfaces, particularly in samples functionalized with 5 g/L biomass for three hours, which showed significantly greater cell attachment than both the control and protein-treated samples. These findings highlight the complementary yet distinct roles of S. platensis biomass and protein extract in modulating surface chemistry and cell–material interactions, emphasizing the importance of tailoring biofunctionalization strategies to optimize early biological responses on titanium-based implants. Full article

Pure titanium (Ti) and its alloys are the gold standard for dental implants because a stable titanium dioxide passive film provides excellent corrosion resistance in physiological environments. In this study, we aimed to examine electrochemical interactions between Ti and cobalt–chromium–molybdenum alloy (CoCrMo), and between a novel Ti–magnesium composite (BIACOM TiMg) and CoCrMo, when immersed in everyday solutions representing beverage or oral hygiene exposure. Test solutions included Coca-Cola^®, lemon juice, Elmex^® fluoride gel, Listerine^® Cool Mint, and Sensodyne^® fluoride paste. Immersion experiments paired Ti sticks with CoCrMo sticks and, separately, BIACOM TiMg with CoCrMo sticks, with three measurements per configuration. When galvanically coupled with CoCrMo, immersion in Coca-Cola produced galvanic potential differences of ~983 mV for the BIACOM TiMg-CoCrMo couple and 830 mV for the commercially pure grade 4 (CP4) Ti-CoCrMo couple, indicating significant electrochemical instability. Both materials showed significant potential increases in Elmex fluoride gel. Listerine Cool Mint and Sensodyne fluoride exposure produced electrochemical interactions exceeding 200 mV. Significant differences in corrosion stability were observed between CP4 Ti and BIACOM TiMg. These findings indicate that material pairing and electrolyte environment significantly influence galvanic behavior, with the Ti-Mg composite showing greater susceptibility than CP4 Ti, informing dental/biomedical material selection in oral environments. Full article

Micro-arc oxidation (MAO) coatings were produced on commercially pure titanium Grade 2 using a composite electrolyte containing sodium phosphate (Na₃PO₄) and sodium silicate (Na₂SiO₃), while varying the applied voltage. The surface morphology, phase composition, and structural features of the coatings were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The coatings exhibited a characteristic crater-like microporous surface morphology associated with the micro-arc discharge process. XRD analysis confirmed the formation of mixed TiO₂ phases in the anatase and rutile modifications, with higher voltages promoting the growth of the thermodynamically stable rutile phase. Corrosion and tribological properties were evaluated in a 3.5 wt.% NaCl solution using potentiodynamic polarization and a ball-on-disc test configuration, respectively. The results revealed a substantial improvement in both corrosion resistance and wear performance compared with bare titanium. The coating formed at 300 V demonstrated the highest wear resistance due to its denser microstructure, whereas the coating produced at 350 V exhibited the lowest friction coefficient and the greatest corrosion resistance, attributed to the increased rutile content. Overall, MAO coatings fabricated in the phosphate–silicate electrolyte effectively enhance the combined operational properties of titanium and can be recommended for applications requiring improved wear and corrosion resistance. Full article

Recent studies show that titanium (Ti)-based alloys combine established mechanical strength, corrosion resistance, and biocompatibility with emerging electrical and electrochemical properties relevant to bioelectronics. The main goal of the present manuscript is to give a wide-ranging overview on the use of Ti-alloys in electronics and biomedicine, focusing on a comprehensive analysis and synthesis of the existing literature to identify gaps and future directions. Concurrently, the identification of possible correlations between the effects of the manufacturing process, alloying elements, and other degrees of freedom influencing the material characteristics are put in evidence, aiming to establish a global view on efficient interdisciplinary efforts to realize high-added-value smart devices useful in the field of biomedicine, such as, for example, implantable apparatuses. This review mostly summarizes advances in surface modification approaches—including anodization, conductive coatings, and nanostructuring that improve conductivity while maintaining biological compatibility. Trends in applications demonstrate how these alloys support smart implants, biosensors, and neural interfaces by enabling reliable signal transmission and long-term integration with tissue. Key challenges remain in balancing electrical performance with biological response and in scaling laboratory modifications for clinical use. Perspectives for future work include optimizing alloy composition, refining surface treatments, and developing multifunctional designs that integrate mechanical, biological, and electronic requirements. Together, these directions highlight the potential of titanium alloys to serve as foundational materials for next-generation bioelectronic medical technologies. Full article

The TC4 alloy is widely used in aerospace and marine engineering due to its excellent mechanical properties and corrosion resistance. However, titanium alloys often face fretting wear problems during use, which affect their long-term stability and service life. This study investigates the effects of surface mechanical attrition treatment (SMAT) time on the surface morphology, microstructure, stress distribution, and fretting wear properties of TC4 alloy. Characterization was performed using white light interferometry, EBSD, SEM, XRD, and microhardness measurements. The results show that SMAT significantly changes the surface and wear properties of TC4 alloy. With the increase in SMAT time from 0 to 240 min, the surface roughness (Ra), hardness, deformation depth, and stress gradually increase while the grain size decreases. After 240 min of SMAT, the TC4 alloy exhibited optimal fretting wear resistance, achieving a wear depth of 14.27 μm, a wear volume of 2.48 × 10⁶ μm³, and a wear rate of 1.24 × 10³ μm³/s. This represents a significant improvement, corresponding to an approximate 32.8% reduction in wear depth and a ~48% reduction in both wear volume and wear rate compared to the untreated sample. Full article

The cleanliness and functionalization of metal surfaces are critical factors to determining their performance in high-performance microelectronic packaging, reliable biomedical implants, advanced composite bonding, and other fields. Compared to traditional wet cleaning methods, plasma cleaning technology has emerged as a research hotspot in surface engineering due to its unique advantages, such as high efficiency and environmental friendliness. It operates under versatile conditions (e.g., power: tens of watts to several kilowatts; pressure: atmospheric to low vacuum; treatment time: seconds to minutes), enabling not only efficient contaminant removal but also targeted surface functionalization, including dramatically enhanced hydrophilicity (e.g., contact angles from >80° to <10°), significantly improved adhesion (e.g., up to 40% increase in bond strength), and modifications in surface roughness, corrosion resistance, and biocompatibility. This review systematically elaborates on the physical, chemical, and synergistic mechanisms of plasma cleaning technology as it acts on metal surfaces. It focuses on plasma cleaning applied to copper, aluminum, titanium and their respective alloys, as well as alloy steels, providing a detailed analysis of contaminant types, plasma cleaning methodologies, common challenges, surface functionalization responses, and subsequent functional applications. Furthermore, this review discusses the current challenges faced by plasma cleaning technology and offers perspectives on its future development directions. It aims to systematize the research progress in plasma cleaning of metal surfaces, thereby facilitating the transition of this technology towards large-scale industrial applications for metal surface functionalization. Full article

Background: Postoperative infections remain a major complication in spinal surgeries involving intersomatic screws, often compromising osseointegration and long-term implant stability. Questions/Purposes: This study evaluated a nanotextured titanium oxide surface with nanopillar-like morphology designed to reduce bacterial colonization while preserving mechanical integrity and promoting bone integration. Methods: Ti₆Al₄V screws were studied in three batches: control, passivated with HCl and acid mixture treatment to obtain nanotopographies on the surfaces. To create the nanotopographies, the screws were treated with a 1:1 (v/v) sulfuric acid–hydrogen peroxide solution for 2 h. Surface morphology, roughness, wettability, and surface energy were analyzed by SEM, confocal microscopy, and contact angle measurements. Corrosion and ion release were assessed electrochemically and by ICP-MS, respectively. Mechanical behavior, cytocompatibility, mineralization, and antibacterial efficacy were evaluated in vitro. Osseointegration was analyzed in rabbit tibiae after 21 days by histology and bone–implant contact (BIC). Results: The treatment produced uniform nanopillars (Ra = 0.12 µm) with increased hydrophilicity (49° vs. 102° control) and higher surface energy. Mechanical properties and fatigue resistance (~600 N, 10 million cycles) were unaffected. Corrosion currents and Ti ion release remained low. Nanopillar surfaces enhanced osteoblast adhesion and mineralization and reduced bacterial viability by >60% for most strains. In vivo, Bone Index Contact (BIC) was higher for nanopillars (52.0%) than for HCl-treated (43.8%) and control (40.1%) screws, showing a positive osseointegration trend (p > 0.005). Conclusions: The proposed acid-etching process generates a stable, scalable nanotopography with promising antibacterial and osteogenic potential while maintaining the alloy’s mechanical and chemical integrity. Clinical relevance: This simple, scalable, and drug-free surface modification offers a promising approach to reduce postoperative infections and promote bone integration in spinal implants. Full article

Titanium alloys are widely used for biomedical implants, but their performance is limited by wear, corrosion, and susceptibility to bacterial colonisation. To overcome these drawbacks, multilayer Ti–Cu oxide coatings were deposited on Ti6Al4V substrates using direct current magnetron sputtering. Two multilayer architectures (6 × 2 and 12 × 2 TiO₂/CuO bilayers) were fabricated and evaluated for their structural, mechanical, electrochemical, and biological properties. SEM/EDS and XRD confirmed well-adhered crystalline coatings consisting of rutile/anatase TiO₂ and monoclinic CuO with uniform elemental distribution. The coatings increased surface roughness, improved adhesion, and enhanced hardness by up to ~180% compared to uncoated Ti6Al4V alloy. Compared to the bare substrate, electrochemical testing in simulated body fluid showed higher corrosion resistance of both coated samples, but particularly for the 12 × 2 multilayers. Both architectures provided sustained Cu²⁺ release over seven days without a burst effect. In vitro biological testing showed that both multilayer coatings achieved over 96% inhibition of Gram-positive bacteria such as Staphylococcus aureus and Bacillus subtilis, while exhibiting moderate antibacterial effects against Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa). Despite the presence of copper, MG-63 osteoblast-like cells demonstrated sustained viability and successful extracellular matrix mineralisation, indicating excellent cytocompatibility of the coatings with bone-forming cells. These results demonstrate that multilayer Ti–Cu oxide coatings can effectively balance antibacterial performance, corrosion resistance, mechanical strength, and support bone cell integration, making them a promising strategy for the surface modification of titanium-based biomedical implants. Full article

Research into methods for regulating the biocorrosion rate of biodegradable magnesium implants is one of the most urgent tasks in the field of biomedical materials science. Atomic layer deposition (ALD) is a highly effective method for the preparation of nanocoatings, which can be used to regulate the biodegradation rate. The present paper presents the findings of a research study in which the most commonly used simple oxide ALD coatings (Al₂O₃, TiO₂, and ZnO) were examined, in addition to mixed coatings obtained by alternating ALD cycles of the application of ZnO-TiO₂ (ZTO) and Al₂O₃-TiO₂ (ATO). The coating thicknesses exhibited a variation within the most typical range for ALD coatings, measuring between 20 and 80 nanometres. The biocorrosion testing was conducted in Ringer’s physiological solution through the measurement of potentiodynamic polarisation curves and impedance spectroscopy. The findings demonstrated that, for Al₂O₃ coatings, the protective properties exhibited an increase with increasing thickness, while for TiO₂, the trend was found to be dependent on the type of precursor utilised. The protective properties of titanium tetraisopropoxide (TTIP) have been observed to increase with increasing thickness. Conversely, the protective properties of titanium tetrachloride (TiCl₄) have been observed to decrease. The application of mixed ZTO oxides with a thickness of 40 nm has been demonstrated to reduce the corrosion current by 1.7 and 3.4 times, depending on the use of TiCl₄ or TTIP. Furthermore, the effectiveness of ATO coatings of similar thicknesses has been shown to be higher, with a reduction in corrosion currents of 54 and 24 times for samples obtained using TiCl₄ and TTIP, respectively. A thorough analysis of the collected data unequivocally demonstrates the superior efficacy of mixed oxides in comparison to their pure oxide counterparts. Full article

Ti-6Al-4Zr-3Nb-1.1Mo-1Sn-1V (Ti90) alloy is widely used in marine engineering and oil and gas extraction due to its excellent strength, impact toughness, and corrosion resistance. The corrosion behavior of Ti90 alloy after solution treatment at 750 °C, 900 °C, 940 °C, and 960 °C in 5 M hydrochloric acid (HCl) solution was investigated using open-circuit potential (OCP), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), static immersion tests, and surface characterization. The results of electrochemical tests indicate that the corrosion resistance of Ti90 alloy increases with rising solid solution temperature. The static immersion tests show that the variation trend of the annual corrosion rate at different solid solution temperatures in 5 M HCl solution is consistent with the electrochemical test results. The corrosion morphology of Ti90 alloy reveals that the α phase is more prone to decomposition than the β phase. The corrosion behavior of Ti90 alloy in 5 M HCl solution is mainly influenced by the volume fraction of the β phase and the size of the α phase. Full article

Background/Objectives: The purpose of this study was to assess the in vitro biocompatibility and corrosion resistance of five titanium alloys that have been recently developed for dental implant applications, whose compositions were designed to align with current approaches in the development of novel biomaterials. Priority was given to limiting the harmfulness associated with specific chemical elements present in common conventional alloys and increasing corrosion resistance to improve the biomaterial–tissue cellular interaction. Methods: For this purpose, five types of titanium alloys with original chemical compositions (Ti1–Ti5) were developed. The electrochemical behavior of the alloys was analyzed by evaluating the corrosion resistance in environments that simulate the oral environment, as well as the cellular behavior, by evaluating the viability, growth, and proliferation of human cells on osteoblasts and gingival fibroblasts. Detailed analysis of the chemical composition by scanning electron microscope (SEM/EDS) methods was used. The corrosion rate of the alloys in artificial saliva was tested using the polarization resistance technique (Tafel). Human osteoblasts (hFOB cell line) and human gingival fibroblasts (hFIB-G cell line) were used to measure biocompatibility in vitro. Results: The Ti5 alloy demonstrated the highest cell viability and the lowest corrosion rate (0.114 μm/year) among all tested compositions, with the Ti3 alloy containing Mo and Zr following closely behind. The Ti2 alloy exhibited reduced biocompatibility because of the inclusion of Ni and Fe in its composition. Conclusions: Taken together, the results of this study provide useful information on the basic characteristics of titanium alloys with original chemical compositions. The titanium alloys were analyzed in comparison with common conventional alloys (Cp–Ti and Ti6Al4V) as well as alloys such as Ti–Zr, Ti–Nb, and Ti–Nb–Zr–Ta, which are considered to be viable alternatives to conventional materials for making dental implants. Full article

To enhance the abrasion resistance of TC4 titanium alloy and meet the demand for wear-resistant and corrosion-resistant friction pair materials for water-hydraulic components of marine equipment, the tribological properties of the material subsequent to ultrasonic rolling extrusion surface strengthening under seawater-lubricated conditions were investigated. The process of ultrasonic rolling machining was simulated and analyzed by the finite element method. The influence of process parameters on surface residual stress and surface roughness of TC4 was studied, and the appropriate range of process parameters was determined. The effects of key process parameters such as rolling times, static pressure, amplitude, and rotational speed on the surface properties of TC4 were investigated by the single-factor test method. Based on the response surface methodology, a prediction model of surface hardness and roughness of TC4 was constructed, and the process parameters were optimized and analyzed. The friction coefficient, wear amount, and wear rate of TC4 and CFRPEEK under seawater lubrication before and after strengthening were studied by wear tests. The wear morphologies of the specimens prior to and subsequent to strengthening were analyzed, and the friction and wear mechanisms were explored in depth. The results indicate that ultrasonic rolling extrusion surface strengthening process facilitates grain refinement in the surface layer of TC4, enhances surface hardness, and optimizes surface roughness, thereby improving its wear resistance. This is of guiding significance to the design and use of hydraulic components in seawater and has a promoting effect on the development of marine equipment. Full article