This study systematically investigates the effects of Ta addition (5-10 at%) on the microstructure, phase transformation behavior, mechanical properties, and X-ray visibility of arc-melted NiTiTa shape-memory alloys. Microstructural characterization reveals that Ta acts as both a beta-phase stabilizer and a grain-growth inhibitor, promoting the formation and redistribution of Ta-rich secondary phases and leading to pronounced grain refinement via solute-induced lattice distortion and Zener pinning. With increasing Ta content and thermomechanical processing, the morphology of beta-Ta evolves from relatively continuous grain-boundary features to lamellar structures aligned with the rolling direction. X-ray Diffraction (XRD) analysis indicates that Ta addition induces anisotropic distortion of the B19 ' martensitic lattice, while Differential Scanning Calorimetry (DSC) measurements show a modest upward shift in martensitic transformation temperatures. Mechanical testing demonstrates a composition-dependent strength-ductility tradeoff, with alloys containing 5-6 at% Ta achieving an optimal balance between high tensile strength and adequate elongation, whereas higher Ta contents lead to reduced ductility. In addition, increasing Ta content significantly enhances radiopacity due to Ta's high electron density, enabling tunable X-ray visibility while preserving the functional advantages of NiTi-based SMAs. These results provide practical guidelines for designing NiTiTa alloys for biomedical applications requiring a balance among mechanical performance, phase stability, and imaging visibility.

The growing demand for compact, high-performance energy storage in microelectronic and wearable systems necessitates the development of supercapacitor electrodes with both high energy and power densities. However, achieving these characteristics while maintaining device miniaturization remains a major challenge. This study aims to address this issue by designing a three-dimensional chromium-doped carbon nanosheet electrode based on nickel foam loading for symmetrical button-type supercapacitors. ZIF-67 nanosheets were first grown in situ on nickel foam via a liquid-phase self-assembly method, followed by the deposition of chromium-doped carbon films through magnetron sputtering. By systematically varying the chromium target current, the doping concentration and film microstructure were precisely controlled to optimize electrochemical performance. The synergistic combination of ZIF-67 nanosheets and chromium-doped carbon films enhances electrical conductivity, ion diffusion, and structural stability. Under optimized conditions (0.3 A sputtering current), the electrode achieved an areal capacitance of 1508 mF cm- 2, and the assembled device exhibited an energy density of 6.51 mWh cm- 2 and a power density of 400 mW cm- 2. The superior performance arises from the formation of a conductive Cr-C network that provides abundant active sites for charge storage and rapid charge-transfer pathways, while the high specific surface area of the ZIF-67 nanosheets further increases the number of electrochemically accessible sites, facilitating efficient ion diffusion and charge transport. This study demonstrates a controllable fabrication strategy that not only enhances the energy and power performance of carbon-based electrodes but also promotes the miniaturization of high-performance micro-supercapacitors for nextgeneration portable electronics.

Bone cements (BCs) are multifunctional scaffolds in orthopedic treatments to offer the necessary early-healing stability and physico-chemical functionality for bone tissue regeneration, which presents tailorable performance to address diverse clinical demands under the current trend of personalized healthcare. However, even the most extensively applied commercial BCs, such as polymethyl methacrylate (PMMA) and calcium phosphate cement (CPC), have distinctive limitations (e.g., unsuitable biodegradability and low mechanical strength). Cutting-edge nano technologies have become popular in the last two decades for multifunctional enhancement of BCs. This paper overviews the latest advancements on the development of BCs using nano technologies in terms of mechanical enhancement, biodegradability tuning, and antibacterial capability improvement. The nano technologies have been reviewed both in the aspects of various types of nano additives as functional additives and the associated techniques for incorporating nano additives into BCs, where fundamental theories and the necessary underlying mechanisms were also discussed. In particular, BCs using different nano-engineering strategies are compared, and the existing gaps between research development and clinical application are discussed. This review aims to bridge the gap between the rapid advancement of BCs driven by nano technologies in laboratory-based environment and its clinical applications.

In the field of shape-memory alloys (SMAs), Nickel-Titanium-Tantalum (NiTiTa) alloys have garnered significant interest due to their superior properties compared to traditional Ni-Ti alloys. This review summarizes the advances in NiTiTa SMAs, focusing on their microstructures, mechanical properties, biocompatibility, X-ray visibility, and corrosion resistance. It discusses innovative methods like heat treatment, alloying, and surface treatment to tailor these properties. The review highlights the potential of NiTiTa alloys in biomedical devices, aerospace engineering, and precision mechanics, and suggests future research directions to improve their performance under extreme conditions.

The limited corrosion resistance of metallic bipolar plate coatings under high potentials remains a critical barrier to their application in proton exchange membrane fuel cells (PEMFCs). In this study, carbon doped TiO2 coatings were deposited via magnetron sputtering and subjected to long-term potentiostatic corrosion at 1.6 V (vs. SHE) for 20 h to evaluate their electrochemical durability. Surface morphology, interfacial contact resistance (ICR), and corrosion mechanisms were comprehensively analyzed before and after corrosion. C doping led to the formation of TiC phases and facilitated partial phase transitions from TiO2 to Ti2O3 and TiO, resulting in a significant reduction in ICR. However, this structural modification concurrently compromised corrosion resistance. Among the tested samples, the lightly doped C1 sample coating demonstrated excellent performance, maintaining structural integrity with minimal degradation. Its corrosion current density after 20 h at 1.6 V (vs. SHE) was as low as 2.93 x 10(-6) A/cm(2), while the ICR increased from 3.89 to 20.86 m Omegacm(2), indicating sustained conductivity under high potential conditions. In contrast, heavily doped samples exhibited significant phase degradation and surface deterioration. XPS and EIS analyses revealed that the loss of electrical conductivity was primarily attributed to the oxidation of Ti2O3 to TiO2, initiated by pitting and uniform corrosion. These results demonstrate that controlled carbon doping can simultaneously optimize conductivity and corrosion stability, with the C1 composition showing the best compromise for use in PEMFC bipolar plates under high-potential operation.

To enhance the long-term high potential corrosion resistance of metal bipolar plates, carbon doped TiO2 films were deposited on 316L stainless steel using reactive magnetron sputtering. The structure and surface morphology of the coatings were systematically controlled by adjusting the oxygen flow rate. The study investigates the structural transformation of TiO2 under varying oxygen flow rates, focusing on the principles of corrosion resistance and conductivity for applications in fuel cell bipolar plates. The coating exhibits different corrosion behaviors under various potentiostatic polarization potential. The C doped TiO2 film prepared at an oxygen flow rate of 30sccm demonstrated the lowest corrosion current density, exhibiting no significant corrosion after 5 h of potentiostatic polarization at +1.6V (vs. SHE), with a corrosion current density of 1.04 mu A/ cm2. The primary corrosion mechanisms observed were uniform corrosion and pitting corrosion. By optimizing the oxygen flow rate, conductive pathways comprising Ti2O3 and TiO phases were formed, significantly reducing the interfacial contact resistance. Notably, samples prepared at oxygen flow rated of 25 sccm and 30sccm achieved excellent interfacial contact resistance values of 2.46 mS2 cm2 and 2.78 mS2 cm2, respectively.

The rising incidence of biliary diseases, driven by an aging population and lifestyle changes, has elevated the importance of biliary stenting. This review aimed to systematically evaluate recent advancements in biliary stent materials and coatings, assessing their role in treating biliary stenosis and obstruction, with an emphasis on multifunctional coatings to enhance stent safety, efficacy, and patient outcomes while minimizing complications. Antimicrobial coatings, such as those with silver ions or chitosan, reduce infection risk; drug-eluting coatings, incorporating antibiotics or paclitaxel, mitigate infection and tumor progression; antiadhesion coatings extend stent patency. Furthermore, 3D printing enables patient-specific stent designs for optimal fit, while smart stents with integrated sensors enhance therapeutic precision by monitoring biliary parameters in real time. Multifunctional coatings and advanced materials substantially improve biliary stent performance, offering safer and more effective treatment options for biliary diseases. This review synthesizes the advantages and challenges of current technologies and recommends that future research should prioritize smart stents, biodegradable materials, and multifunctional coatings, validating their long-term safety and efficacy through clinical trials to optimize patient outcomes and advance clinical applications.

Improving the electrical conductivity and corrosion resistance of metal bipolar plates is crucial for proton exchange membrane fuel cells (PEMFCs). In this study, protective coatings with titanium as the base layer and amorphous carbon as the top layer were deposited on 316L stainless steel using a filtered cathodic vacuum arc (FCVA) deposition system. The effect of bias voltage on the morphology, composition, corrosion resistance, and interfacial contact resistance (ICR) of the amorphous carbon coatings was systematically investigated, with the corrosion mechanisms and surface property changes after corrosion were analyzed. During potentiostatic polarization tests at 0.6V (vs. SCE) and 1.3V (vs. SHE) for 10 h, corrosion current densities for all coatings were below 1 x 10- 7 A/cm2 and 1.5 x 10-6 A/cm2. Even after potentiostatic polarization at 1.6V (vs. SHE), the ICR before and after electrochemical corrosion remained as low as 4.26 S2 cm2 and 3.81 S2 cm2. The coatings demonstrated excellent corrosion resistance and low ICR. Additionally, the degradation mechanism of the coatings under high-potential corrosion conditions was examined.

Characterized by their complex multicomponent systems, high-entropy ceramic thin films (HECs) have attracted much attention due to their unique properties, such as enhanced thermal stability, mechanical strength, and distinctive electronic characteristics. These materials, composed of at least four different cations or anions in a single phase and driven by high configurational entropy, can have potential applications in a wide range of fields such as protective coatings, diffusion barriers, and thermal barrier coatings. This review reviews the recent advances in the concept, classification, synthesis, and structure-functional exploration of HECs. This review also discusses the challenges associated with thermal stability, atomic distribution, and the effects of multi-element incorporation, emphasizing the need for advanced theoretical models and experimental strategies to further explore the potential of these innovative materials.

Nuclear energy is essential for the future development of countries. However, both structural and functional components of nuclear power equipment are facing severe challenges of nuclear irradiation damage after experiencing irradiation growth and irradiation creep. How to avoid irradiation damage to nuclear power equipment has become a hotspot in international research and development of surface protection technology. Deposition of protective coatings on the underlying object surface or in bulk materials has been considered as a near-term solution to enhanc functional components. Different substrate materials are selected according to other service conditions within the reactor. Suitable material selection combined with relevant optimization can significantly increase the service life of materials. This review summarizes recent research on several categories of anti-irradiation coatings prepared by physical vapor deposition technology for current industrial applications. These includes metallic, ceramic, composite and high entropy alloy coatings. The review endeavors to impart a thorough understanding of the properties of these selected anti-irradiation coatings, from the fundamental aspects of their substrate materials to their practical applications across diverse settings. It explores not only the current research progress but also the potential avenues for future advancements. Additionally, the intricate relationships between coating formulations, their resistance to irradiation, and their ultimate performance in various environments are illuminated in this paper.

Moderate doping of heterogeneous elements can effectively solve the problem of insufficient adhesion between diamond-like carbon (DLC) thin films and substrates,leading to film detachment.In recent years,tantalum (Ta) has been introduced as a new metal dopant in carbon-based thin films,which can significantly improve the mechanical and tribological properties of the films.As a biocompatible metal with high melting point,wear resistance,corrosion resistance,high ductility,and excellent biocompatibility,tantalum exhibits structure and mechanical properties similar to human bones,promoting the proliferation and osteogenesis of human osteoblast cells.However,there is still limited research on tantalum-doped DLC films,especially regarding their biocompatibility. This study aims to explore the structural transformation of tantalum-doped DLC films and enhance their mechanical properties,tribological performance,and biocompatibility.The non-equilibrium magnetron sputtering technique was employed to deposit the films,and the tantalum doping level was controlled by adjusting the power of the tantalum target.DLC films with different Ta doping levels were prepared at power levels ranging from 0 to 0.5 kW.The films were characterized in terms of microstructure,chemical composition,friction performance,mechanical properties,and biocompatibility.The relationship between tantalum doping level and film performance was investigated to identify the optimal tantalum doping ratio and obtain DLC films with excellent performance,laying a foundation for their widespread applications in surface modification of artificial joints and other fields. The results showed that the inclusion of tantalum increased the carbon deposition rate,leading to an increase in film thickness.The sp3-C content in the films initially increased and then decreased with the increase of the Ta doping level.TaC crystals and Ta—Ta nanoclusters were observed in the DLC films doped with Ta at 0.2 kW and above,which resulted in an initial increase and subsequent decrease in surface roughness.Compared with undoped DLC films,Ta-doped DLC films exhibited several improvements.The film-based bonding force increased from 10 N to 25 N,leading to enhanced adhesion between the film and the substrate.The fracture toughness also improved from 0.6 Mpa·m1/2 to a value of 1.6 Mpa·m1/2 or higher.This indicated that the Ta-doped DLC films were more resistant to crack propagation,making them more mechanically robust.In terms of friction properties,the dry friction coefficient decreased from 0.45 to a range of 0.1 to 0.15.This meant that the Ta-doped DLC films experience reduced friction when in contact with dry surfaces.Similarly,the wet friction coefficient decreased from 0.35 to around 0.1,indicating improved lubrication and reduced friction under wet conditions.Moreover,the wear rate associated with dry friction diminished significantly from 4500×10-6 mm3/(N·m) to 7×10-6 mm3/(N·m) or lower.The wet friction wear rate also decreased to 1×10-6 mm3/(N·m).This suggested that Ta-doped DLC films exhibited superior wear resistance,making them more durable in both dry and wet environments.However,there were slight compromises in other aspects.The elastic modulus of Ta-doped DLC films experienced a slight decrease,indicating a slight reduction in their stiffness.Additionally,the wettability of the films also underwent a slight decrease.In addition,by simulating body fluid immersion,Ta doped thin films exhibited good capability in inducing hydroxyapatite formation,with a calcium-to-phosphorus (Ca/P) ratio ranging from 1.4 to 1.65,close to the Ca/P ratio in the human body.No cytotoxicity was observed for either doped or undoped films. In summary,the doping of Ta significantly improves the tribological and mechanical properties of DLC films,as well as the capability to induce hydroxyapatite formation.Therefore,these films have the potential to be used as a bio-protective layer on the surface of implants.The Ta-DLC film exhibits the best overall performance at Ta-0.4 kW.

During the past two decades, aerobic bacteria induced biomineralization has gained popularity for autonomous sealing of cracks in concrete structures due to its environmentally friendly characteristics of carbon retention. However, the mechanism of the biomineralization induced by aerobic bacteria for concrete crack sealing is still unclear due to the complex chemistry of cement matrix. Also, as the main nutrient for bacterial growth, the effect of yeast extract (YE) on biomineralization should be properly evaluated. For the first time, this study investigates the effects of YE and calcium content on the development of nanostructure and chemical composition of cement matrix during the biomineralization process induced by aerobic bacteria Bacillus cohnii. The effects of calcium content were realized by constructing a simulated cement mixture consisting of calcium hydroxide and synthesised C-S-H with different C/S ratios. The effects of YE content were evaluated by the addition of different amounts of YE into simulated cement mixture with different C/S ratios. Results suggest that 10g/l of YE can cause a high pH value of 10 and an unsuccessful growth of bacteria in simulated cement mixture with C/S ratios 0.6 and 0.8. Upon increasing the YE from 10 g/l to 20 g/l, the pH reduced from 10 to 9 and the bacteria was successfully grown. Higher amounts of bicarbonate ions can cause an enhanced decalcification of synthesised CS-H rather than calcium hydroxide. The aerobic bacteria Bacillus cohnii showed superior performance on calcium absorption and calcite precipitation, being a promising way for practical concrete crack sealing.

This study focuses on Cr2O3 2 O 3 prepared via reactive magnetron sputtering, a direct deposition technique that significantly impacts the microstructure and optoelectronic properties of the films. Reactive sputtering alters grain size, density, and surface morphology, which in turn affects the structural order and stoichiometry. By adjusting the ratio of process gases, particularly the oxygen partial pressure, the stoichiometry of the deposited films was controlled. This is crucial for managing the oxidation state of chromium and the concentration of free electrons. An optimal oxygen partial pressure of 75 % was identified, substantially reducing oxygen interstitial defects in the CrOx x materials and enhancing conductivity by nearly two orders of magnitude. Additionally, increasing the oxygen partial pressure helped integrate more oxygen atoms into the lattice, transitioning the electronic structure from a metallic state in CrO2 2 to a semiconductive state in CrO3. 3 . This fine-tuning of oxygen doping not only adjusts carrier concentrations but also optimizes the photoelectric properties of the materials, achieving a tailored high band gap of 3.34 eV. This study highlights the potential of reactive magnetron sputtering to customize semiconductor materials through oxygen doping, offering a novel approach to enhance the versatility and application range of chromium oxide materials in advanced technological applications.

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To improve the corrosion resistance and interfacial contact resistance (ICR) 316L stainless steel bipolar plates used in proton exchange membrane fuel cells (PEMFCs), a series of three -layer amorphous carbon films were prepared by magnetron sputtering. The corrosion resistance and ICR of 316 L stainless steels are greatly improved by the Cr, N doped amorphous carbon and multilayer film structure. Ti and CrN were basement layer and transition layer, and amorphous carbon doping with Cr and N was the top layer. Nitrogen atoms, as the variable atoms, were added into the top layer, focusing on the relation between the N content and the film properties. First principles calculations were used to analyze the bond structure by Cr, N doping into amorphous carbon structure and to determine the reasons for the structural changes in the coating after doping the elements. The results revealed that the films are about 1.05 mu m thick and without apparent defects. With increasing nitrogen flow rate, Cr-N bonds and C-N bonds appeared in the coating while promoting the graphitization of amorphous carbon. Compared with that of Cr-doped amorphous carbon coated steel, the corrosion current density of Cr, N co -doped amorphous carbon decreased to 8.1 x 10 -9 A/cm 2 in the +0.6 V (vs. SCE) potentiostatic polarization test, and as the ICR decreased to 1.3 m Omega cm 2 , the film exhibited outstanding corrosion resistance and conductivity properties. The Cr, N co -doped amorphous carbon/CrN/Ti composite film formed on 316L stainless steel might be appropriate used in PEMFCs.

Amorphous carbon films have recently attracted extensive attention as surface functional films for bipolar plates with excellent conductivity and anti-corrosion properties. In this research, to determine the influence of the amorphous carbon film doped with titanium and nitrogen on the efficiency of proton exchange membrane fuel cells (PEMFCs) and clarify the effect of N atoms on Ti doped amorphous carbon, a series of Ti, N co-doped amorphous carbon films are built on 316L stainless steel at different N2 flow rates. This study provides detailed research about the influence of N atoms content on the microstructure, morphology evolution, corrosion resistance and interfacial contact resistance (ICR) of Ti, N co-doped amorphous carbon films. The results reveal that the N doping of the Ti-doped amorphous carbon film has the potential to enhance the C-sp2 content and refine the grain. The characterization results indicate that introducing N atoms into Ti doped amorphous carbon can reduce the ICR of the film to 2.38 m Omega cm2. The introduction of N atoms can also enhance the anti-corrosive characteristics of the titanium singly doped amorphous carbon film. The Ti, N co-doped film can be used as candidate materials applied to metal bipolar plates.

In order to obtain films with high corrosion resistance and excellent interfacial contact resistance (ICR) on 316L stainless steel used for bipolar plates in proton-exchange membrane fuel cells (PEMFCs), Cr, Ti co-doped amorphous carbon films were prepared on 316L stainless steel. The preparation method for the coating was magnetron sputtering. The doping amount of the Ti element was controlled by a Cr target and a Ti target current. The change in the structure and properties of the coating after the change from Cr single-element doping to Cr and Ti co-doping was studied. The change rule of the structure and properties of the coating from Cr single-element doping to Cr and Ti co-doping was studied. An increase in the Ti content led to a decreased grain boundary, a flatter surface, and a higher sp2-hybridized carbon content. TiC and CrC nanocrystals were formed in the amorphous carbon structure together. The amorphous carbon films doped with Cr and Ti simultaneously achieved a low ICR and high corrosion resistance compared with single-Cr-doped amorphous carbon. The enhanced corrosion resistance was attributed to the decreasing grain boundary, the formation of the TiC crystal structure, and the smaller grain size. The best performance was obtained at a Ti target current of 2A. Compared with bare 316L stainless steel, the corrosion resistance of Cr, Ti co-doped amorphous carbon (Icorr = 5.7 × 10−8 A/cm2, Ti-2 sample) was greatly improved. Because Ti doping increased the content of sp2-hybridized carbon in the coating, the contact resistance of the coating decreased. Moreover, the interfacial contact resistance was 3.1 mΩ·cm2 in the Ti-2 sample, much lower than that of bare 316L stainless steel. After the potentiostatic polarization test, the coating still had excellent conductivity.