Titanium Layer Research Articles

In-Depth Analysis on the Fabry-Perot Effect of Cs2AgBiBr6 Double Perovskite-Based Solar Cells via Optical Path Length Modulation

Herein, the Fabry-Perot (F-P) interference of cesium silver bismuth bromide (Cs2AgBiBr6) double perovskite solar cells has been analyzed by modulating the optical path length of each layer step by step using the finite-difference time-domain (FDTD) method. The study was performed pass through three main steps. In step 1, for the fluorine-doped tin oxide (FTO)/Cs2AgBiBr6 double perovskite/gold (Au) architecture, we increased the absorption layer thickness from 150 to 600 nm at intervals of 150 nm and then predicted the optical performance including the absorption and reflection. In step 2, titanium dioxide (TiO2) layer was added between FTO electrode and Cs2AgBiBr6 double perovskite and then scaled from 20 to 200 nm at intervals of 20 nm. In the analysis process, short-circuit current density (Jsc) repeatedly fell and rose as the TiO2 layer thickness increased, and when TiO2 layer thickness is 100 nm, Jsc showed the highest value of 13.91 mA/cm2. In step 3, by applying a spiro-OMeTAD layer between the Cs2AgBiBr6 double perovskite absorption layer and Au electrode, the Jsc showed a continuous increase with slight decrease as the spiro-OMeTAD layer thickness increased from 110 to 200 nm, and when the spiro-OMeTAD layer thickness was 200 nm, Jscwas calculated as 14.57 mA/cm2, which is the highest value in the range. In the case of the optimal condition of full structure device, the Fabry-Perot resonance peaks were discovered at 477, 520, 572, 659, and 778 nm five wavelength regions, and the influence of the Fabry-Perot resonance on the generation rate inside the absorption layer on the 520, 572, and 659 nm monochromatic wavelength light was analyzed according to the position in the device. Our study approaches the Cs2AgBiBr6 double perovskite solar cell from an F-P cavity perspective and shows the light trapping phenomenon of the device according to the optical path length modulation.

DIAGNOSTICS OF INSTRUMENTAL MATERIALS BASED ON THE RESULTS OF MODELING OF COATINGS OF INSTRUMENTAL MATERIAL

Computer modeling makes it possible to predict the adhesion properties of various materials and monolayers in the material at the atomic level. As a result of this approach, it is possible to diagnose the operational properties of the tool material according to the calculated values of the adhesion energy of the layers in the tool coating. The issues of studying the adhesive properties of monolayers successively deposited on a hard alloy VK8 are considered. The adhesive properties of Ti, TiN and (Ti, Cr, Al)N layers with each other and with WC92-Co8 hard alloy are investigated. The dependence of the adhesion energy of titanium to WC and Co surfaces depending on the thickness (from one to three atomic layers) of the deposited titanium layer has been studied. For four variants of the compound structure (Ti, Cr, Al)N the adhesion energy of this compound to the TiN surface is calculated. An approach to predicting rational coatings has been developed. It consists in the calculation (control) of the adhesion energy and the use of the adhesion energy value to diagnose a rational coating option for an instrumental hard alloy VK8.

Physically and Chemically Stable Molybdenum-Based Composite Electrodes for p-i-n Perovskite Solar Cells.

Metal halide perovskite solar cells (PSCs) have garnered much attention in recent years. Despite the remarkable advancements in PSCs utilizing traditional metal electrodes, challenges such as stability concerns and elevated costs have necessitated the exploration of innovative electrode designs to facilitate industrial commercialization. Herein, a physically and chemically stable molybdenum (Mo) electrode is developed to fundamentally tackle the instability factors introduced by electrodes. The combined spatially resolved element analyses and theoretical study demonstrate the high diffusion barrier of Mo ions within the device. Structural and morphology characterization also reveals the negligible plastic deformation and halide-metal reaction during aging when Mo is in contact with perovskite (PVSK). The electrode/underlayer junction is further stabilized by a thin seed layer of titanium (Ti) to improve Mo film's uniformity and adhesion. Based on a corresponding p-i-n PSCs (ITO/PTAA/PVSK/C60/SnO2/ITO/Ti/Mo), the champion sample could deliver an efficiency of 22.25%, which is among the highest value for PSCs based on Mo electrodes. Meanwhile, the device shows negligible performance decay after 2000 h operation, and retains 91% of the initial value after 1300 h at 50-60 °C. In summary, the multilayer Mo electrode opens an effective avenue to all-round stable electrode design in high-performance PSCs.

Ultra-high sensitivity surface plasmon U-channel photonic crystal fiber for hemoglobin sensing

In order to increase the wavelength response range of the U-channel sensor, a numerical study has been conducted and then the sensing structure has been optimized. A sensor in photonic crystal fiber (PCF) is proposed in which a layer of titanium dioxide is coated on the surface of the U-channel and then coated with a gold film. These two different metal films are mainly used to control the Surface plasmon resonance (SPR) peak and the corresponding resonance wavelength, thus changing the sensor performance. Just below the metal layer are two special air holes on either side. They form a leakage window in the center. In the following sections, the effects of these variables on the sensor will be studied in detail by COMSOL. The modal transmission characteristics of this fiber optic sensor are analyzed in this paper. By analyzing the obtained loss spectrum, the energy variation in the surface plasmon polariton (SPP) mode and the influence of the core mode on the sensing performance of the fiber optic sensor presented, the general rule of the optimized PCF-SPR sensor is deduced. In addition, we can make subtle adjustments to the sensor to improve its sensitivity. We found with the refractive index (RI) ranging from 1.26 to 1.42, the maximum wavelength sensitivity is 7500 nm/RIU, which corresponds to a full width at half maximum (FWHM) of 11.83 nm，a figure of merit (FOM) of 634.1 RIU−1. In addition, we also have discussed the sensor and different concentrations of hemoglobin aqueous solution to detect its RI. It is evident from the results that the sensor demonstrates excellent sensitivity and a wide detection range, which is highly desirable for practical diagnostic purposes. The potential of this sensor for clinical trials and its application to medical diagnostics is promising. Compared with complex traditional methods, the PCF has obvious advantages such as clear structure, simple manufacture, high sensitivity and strong environmental adaptability. Moreover, it has the advantage of wide wavelength response range and has a clear development prospect in the field of biochemical sensing. It has foreseeable potential practical value.

LIBS analysis of tritium in thin film-type samples

Evaluating the mole fraction of hydrogen isotopes in a solid is a difficult task. Few methods allow it to be achieved. LIBS is a laser method based on the electronic excitation of elements and the spontaneous emission of characteristic optical lines. On a sample containing hydrogen isotopes, α-type lines can allow the estimate of their total mole fraction. In addition, LIBS is a discriminating method because it can separate the contributions of isotopes. This paper reports the implementation of this method on thin film-type samples containing hydrogen and tritium.They consist of nanometric layers of palladium and titanium on a silicon substrate. Under irradiation of nanosecond laser pulses reaching a fluence of the order of 200 J cm−2, LIBS was performed in argon at atmospheric pressure. A detailed spectroscopic study is performed around the Tα line of wavelength 656.039 nm of the Balmer series (n=3→2) of tritium. An analysis based on the reconstruction of the spectrum under conditions of local thermodynamic equilibrium is carried out. This leads to the estimate of the tritium mole fraction.

Enhancing the bond strength of magnetron-sputtered copper layers on polyimide and polyether ether ketone surfaces through surface modification

This study explores the fabrication of composites involving polyimide (PI) and polyether ether ketone (PEEK) resins with Cu using chemical treatment and sandblasting, followed by plasma cleaning in a vacuum environment charged with Ar. To enhance the bonding strength of Cu to PI and PEEK, vacuum magnetron sputtering was used to deposit an intermediate transition layer of titanium and a plated seed layer of Cu onto the resin. For PI/copper composites, the copper layer’s highest bonding strength was achieved through sandblasting and plasma cleaning for 150 s at a bias voltage of 100 V. For PEEK/Cu composites, the optimal bonding strength of the copper layer was observed after 80 s of plasma cleaning. Surface roughness is important in the bonding strength of the copper layer. Additionally, the Ti transition layer strengthens bonding forces between Cu and both PI and PEEK. X-ray photoelectron spectroscopy revealed Ti–O bond formation with oxygen in the resins and Ti–C bonds within the carbon, indicating chemical interactions that bolstered Cu adhesion to resins. Adjusting the bias voltage had varying effects on the bonding strength of resin/Cu. For PI/Cu, the bonding force decreased with increasing bias voltage (20–150 V) owing to excessive bias voltage causing surface defects on the plated Cu layer, which reduced the density of the plated Cu layer. Conversely, the PEEK/Cu bonding force initially increased with increasing bias voltage due to enhanced surface bombardment. Beyond an optimal point, the bonding force in PEEK/Cu decreased due to unfavorable effects on layer density.

Silver-TiO2 coated D-shaped photonic crystal fiber based SPR sensor for ultrasensitive refractive index detection: design and FEM analysis

Photonic crystal fiber (PCF) based surface plasmon resonance (SPR) sensors are emerging as a promising technology for ultrasensitive detection of various biological and chemical analytes. This paper presents a novel D-shaped PCF based SPR sensor, which has shown great potential for highly sensitive detection of refractive index (RI) changes. The D-shaped configuration is achieved through the polishing of the upper side of the PCF fiber. To enhance sensitivity, a 0.1 μm silver layer is strategically placed between the fiber and analyte, intensifying light–matter interactions. Additionally, a 0.05 μm titanium dioxide (TiO2) layer is employed not only to further boost sensitivity but also to shield the metal from oxidation, ensuring the longevity and stability of the sensor. The finite element method (FEM) is employed to optimize the structural parameters of the sensor design. The findings demonstrate that the proposed SPR sensor is sensitive to RI changes in the 1.31–1.35 range, achieving a peak wavelength sensitivity of 30000 nm RIU−1 and an amplitude sensitivity of −185.33 RIU−1. The sensor holds promise for diverse applications, including chemical and biological sensing, making it a versatile tool with promising implications for advancing sensing technologies in various domains.

Cost-effective titania layers over 100 nm thick – effect of annealing on the structural, morphological, and optical properties

Cost-effective titania layers over 100 nm thick – effect of annealing on the structural, morphological, and optical properties

The interaction of size-selected Ru3 clusters with TiO2: depth-profiling of encapsulated clusters.

Ru is a metal of interest in catalysis. Monodisperse Ru3 clusters as catalytic sites are relevant for the development of catalysts because clusters use significantly lower amounts of precious materials for forming active sites due to the small size of the cluster. However, retaining the mono-dispersity of the cluster size after deposition is a challenge because surface energy could drive both agglomeration and encapsulation of the clusters. In the present work Ru3 clusters are deposited by chemical vapor deposition (CVD) of Ru3(CO)12 and cluster source depositions of bare Ru3 onto radio frequency sputter-deposited TiO2 (RF-TiO2) substrates, TiO2(100), and SiO2. When supported on RF-TiO2, bare Ru3 is encapsulated by a layer of titania substrate material during deposition with a cluster source. Ligated Ru3(CO)12 is also encapsulated by a layer of titania when deposited onto sputter-treated RF-TiO2, but only through heat treatment which is required to remove most of the ligands. The titania overlayer thickness was determined to be 1-2 monolayers for Ru3(CO)12 clusters on RF-TiO2, which is thin enough for catalytic or photocatalytic reactions to potentially occur even without clusters being part of the very outermost layer. The implication for catalysis of the encapsulation of Ru3 into the RF-TiO2 is discussed. Temperature-dependent X-ray photoelectron spectroscopy (XPS), angle-resolved XPS, and temperature-dependent low energy ion scattering (TD-LEIS) are used to probe how the cluster-surface interaction changes due to heat treatment and scanning transmission electron microscopy (STEM) was used to image the depth of the surface from side-on.

Preparation and measurement of a sandwiched Sn atomic beam source for laser resonance ionization mass spectrometry.

Isotope analysis of Sn plays a crucial role in geochemical studies and in monitoring nuclear contamination. Nevertheless, prevalent analytical techniques for examining Sn isotopes encounter the issue of isobaric interference, markedly impacting the accuracy of the test results. Laser resonance ionization mass spectrometry (LRIMS) can effectively overcome the difficulties associated with the isobaric interference inherent in commercial mass spectrometry. In this paper, different amounts of Sn were prepared on Re filaments by electrodeposition and tested via LRIMS. The results showed that the average detection efficiency of LRIMS decreased with increasing total Sn content from 1 μg to 4 μg, and the fluctuations in the test results among the samples increased significantly. Therefore, the electrodeposition process, as well as the composition and morphology of the deposits were characterized by SEM, EDS and XPS; results showed that the degradation of the samples with increasing Sn content was attributed to the complexity of the composition, micro-structure, valence of the deposits, and the interference of various elements. To cope with the anomalies encountered above, the deposits were heat-treated at 600 °C in a hydrogen atmosphere to eliminate detrimental impurities, like Cl, and Sn was effectively reduced to an almost singular atomic state. Furthermore, a titanium layer was covered on the surface of the heat-treated deposit by magnetron sputtering. Ultimately, a highly efficient and stable Sn atomic beam source with a sandwiched structure has been successfully developed and exhibits broad application prospect.

Band alignment of TiO2 by controling Cl content for high-efficiency perovskite solar cells

By optimizing the growth time of the TiO2 electron transport layer, the perovskite cell device prepared by TiO2 with a low interface defect and optimal bandgap matching achieved the highest conversion efficiency of 24.31%.

Conductive filament distribution in nano-scale electrochemical metallization cells.

We report a combined experimental and theoretical study of the spatial distributions and sizes of conductive filaments in nano-scale electrochemical metallization (ECM) cells. Each cell comprises a silver nanocube as active electrode, a titanium dioxide (TiO2) or aluminum oxide (Al2O3) layer as dielectric, and a highly-doped silicon substrate as passive counter electrode. Following electroforming of the ECM cell and subsequent mechanical delamination of the silver nanocubes, current maps at previous particle locations reveal an intriguing metal distribution in the TiO2, with preferential accumulation close to the original locations of the nanocube edges. We assign this behavior to electric field enhancements close to the cube edge positions. In contrast, filaments in Al2O3 layers show a comparatively homogenous distribution, which may be assigned to its lower dielectric permittivity. By increasing the oxide thickness, the total area of conductive spots in the current maps increases monotonically for both materials. Kinetic Monte-Carlo simulations of ion migration dynamics in TiO2 confirm the experimental observations, describing both the preferred locations and oxide thickness-dependent metal loadings associated with filament formation. Overall, our findings are highly valuable for the design of future electrochemical metallization cells, especially in the sub-100 nm regime, where optimal filament control is of major importance for achieving lowest device-to-device variability.

Blood-derived products can moderate the activity of neutrophils isolated after biomaterial implantation in a sheep model

Neutrophils play a pivotal role in both the inflammatory phase and subsequent repair processes, making their activity crucial after contact with biomaterials. Excessive neutrophil activation can lead to complications, including implant rejection, highlighting the importance of modulating their activity. This study investigates the long-term interaction of circulating ovine neutrophils with titanium (Ti) and silicon-doped layer (Si-DLC) coated implants. Additionally, the effects of platelet-rich plasma (PRP), platelet-poor plasma (PPP), and antimicrobial neutrophil crude extract (ANE) on neutrophil activity were assessed. Twelve female sheep were divided into Ti, Si-DLC implant and a control group. Neutrophils were stimulated with PRP, PPP, ovine ANE (oANE), or rabbit ANE (rANE), and their enzymatic activity and reactive oxygen and nitrogen species (RONS) generation were evaluated. Hematological parameters were also analyzed. Results showed no adverse effects at implant sites, and all hematological parameters remained within reference values. Ti and Si-DLC implants did not alter neutrophil activity. PRP significantly increased neutrophil activity and RONS production, while PPP decreased activity. oANE reduced enzymatic activity and RONS generation, indicating potential antiinflammatory effects. rANE showed varied effects on neutrophil function. Both ANEs lacked antimicrobial activity against tested pathogens. This study demonstrates the hemocompatibility of Ti and Si-DLC implants and highlights the potential of blood-derived products in modulating the inflammatory response to implants.

Impact of Gas Pressure on the Adhesion Process of Cold-sprayed Titanium Dioxide layers on Unalloyed Metals

Applying ceramic materials like TiO2 through cold spraying is acknowledged as a complex procedure. The intricacy stems from the need for feedstock particles to undergo plastic deformation to bond with the substrate during cold spraying. However, inducing such deformation in ceramics, known for their hardness and brittleness, is not straightforward. Additionally, the underlying bonding mechanism is not fully clear. This study sought to understand the effects of different substrates and gas pressures on the TiO2 application method. We experimented with TiO2 particles and metals such as copper and aluminum, exposing them to varied gas pressures to delve deeper into the dynamics of cold spraying ceramics onto metallic surfaces. We utilized sophisticated instruments like the focused ion beam and the transmission electron microscope to scrutinize the interfacial structures of TiO2 particles with pure copper (C1020) as well as pure aluminum (AA1050). The data revealed that as we adjusted the gas pressure from 0.7 to 3.0 MPa, there was a corresponding increase in the coating\'s bond strength, registering between 1.52 to 3.46 MPa for C1020 and 0.45 to 4.15 MPa for AA1050. An ultra-thin amorphous oxide layer, under 5 nm in thickness, was detected at the juncture of TiO2 with both metals. The shift in process gas pressure emerged as a pivotal element affecting the bond strength of the TiO2 layer.

Investigation of Hafnium Thin Films for Design of TES Microcalorimeters.

Hafnium is a superconductor with a transition temperature slightly above 100 mK. This makes it attractive for such applications as microcalorimeters with high energy resolution. We report the superconducting properties of Hf films of thicknesses ranging from 60 to 115 nm, deposited on Si and Al2O3 substrates by electron beam evaporation. Besides that, we fabricated and measured combinations of hafnium with thin layers of normal metals, decreasing the critical temperature by the proximity effect. The critical temperature of the studied films varied from 56 to 302 mK. We have observed a significant change in the critical temperature of some films over time, which we propose to prevent by covering hafnium films with a thin layer of titanium.

Nanostructure-performance relationships in titania-only electrodes for the selective electrocatalytic hydrogenation of oxalic acid

The preparation of robust and selective hydrogenation electrodes not based on critical raw materials is a relevant goal for the development of sustainable electrocatalytic processes. Oxalic acid is an emerging intermediate produced from CO2 that can be used to produce valuable, added-value monomers for high-performance polymers by selective electrocatalytic reduction. We demonstrated that with the rapid breakdown anodization (RBA) method, superior-performance TiO2-only electrodes can be directly prepared with a fast and low-cost procedure. The electrodes were based on a conductive Ti substrate, used to generate a roughened titania layer by RBA characterized by an ordered array of vertically aligned TiO2 nanotubes (NTs) on top of them and partially reduced TiO2-x nanoparticles stabilized by the interaction with the NTs layer. In addition, the preparation method leads to highly nanoporous NTs. The electrodes obtained by RBA at 60 V led to the best Faradaic efficiency (FE) to glycolic acid (86 %) and oxalic conversion (48 %) at −0.8 V vs. RHE, superior to the existing literature on TiO2-only electrodes at room temperature. The NTs structural features, such as length and surface roughness, were calculated by AFM and linearly correlated with the oxalic acid conversion and the electrochemical active surface area (ECSA). Additionally, the ECSA was found to be correlated with selectivity, indicating the complex interrelations between the NT nanostructure and performance. This finding emphasizes the importance of controlling the nanostructure as a critical factor in tuning the selectivity toward glyoxylic acid or glycolic acid.

Application of Pulse Techniques for the Electropolishing of Titanium and Gold Alloys in Deep Eutectic Solvents

Electropolishing is widely used industrially to create smooth and bright surface finishings. This technique is particularly relevant for components with complex geometries, especially in the onset of additive manufacturing. (1, 2) As E. J. Taylor showed for different types of materials, pulse techniques can be used to control the surface modification and drive the electrochemical process towards a specific desired result. (3)The changes in the surface layers and concentration profiles caused by shifts in polarization lead to results difficult to attain in constant current/potential conditions, especially in metals that passivate and alloys containing metals with dissimilar electrochemical stabilities.Titanium and noble metal-alloys are materials used in a variety of applications. The passivation layer of titanium is very difficult to remove without using strong acids or fluoride-containing compounds. In the case of noble-metal alloys, the problem lies in the non-uniform dissolution of the material under anodic polarization and in the cyanide-containing electrolytes and strong acids which are used for electropolishing.Water-free solvents have been described by Jacquet for this purpose (4). Ionic liquids and deep eutectic solvents, DES, are increasingly being used to work in potential windows otherwise not reachable in aqueous solutions. Reports indicate that a mixing of choline chloride and ethylene glycol can be used for electropolishing of titanium and other metals (5, 6) and that both dissolution and recovery of Au and Pd is feasible in ionic liquids and deep eutectic solvents. (7, 8)Using DES for electropolishing applications offers therefore an opportunity to substitute dangerous substances, such as cyanide and fluoride compounds. This could increase the scope of application of electropolishing in terms of work safety, recycling and disposal.The aim of this work is to show the interplay between pulse parameters (frequency, pulse height and reverse pulses) and the viscosity of the solution. Together with temperature and convection, pulses can be used to selectively control the dissolution of the metal towards the desired surface finish. Using this principle, an average roughness of 20-30 nm was achieved for titanium samples with complex geometry, both under laboratory conditions as well as in a pilot plant. Furthermore, it will be shown how pulses can be used to control the dissolution of electrochemical less noble elements in gold alloys. Acknowledgements: The project is financially supported by the German Federal Ministry for Economic Affairs and Climate Action (ZIM Program). References W. Han and F. Fang, International Journal of Machine Tools and Manufacture, 139, 1–23 (2019).E. J. Taylor, H. McCrabb, H. Garich and T. Hall, A pulse/pulse reverse electrolytic approach to electropolishing and through-mask electroetching PF Products Finishing, Electroplating, www.pfonline.com (published on 26.09.2011).E. J. Taylor, M. Inman, T. D. Hall, S. Snyder, J. Mammosser and F. Furuta, ECS Meet. Abstr., vol. MA2017-01(24), 1197 (2017).P. A. Jacquet, Trans. Electrochem. Soc., 69(1), 629 (1936).W. O. Karim, J. A. Juma, K. M. Omer, Y. M. Salih, K. H. Aziz and S. B. Aziz, Electrochemistry, 88(5), 447–450 (2020).A. P. Abbott, G. Frisch, J. Hartley, W. O. Karim and K. S. Ryder, Progress in Natural Science: Materials International, 25(6), 595–602 (2015).E. Billy, E. Chainet and F. Tedjar, Electrochimica Acta, 56(28), 10340–10346 (2011).P. Giridhar, K. A. Venkatesan, B. P. Reddy, T. G. Srinivasan and P. R. Vasudeva Rao, Radiochimica Acta, 94(3), 131–136 (2006).

In Situ Measurement of Hydrogen Absorption into Copper-Coated Titanium Using Neutron Reflectometry and Electrochemical Impedance Spectroscopy

We set out to investigate the possibility that a small amount of hydrogen, generated by sulfide-driven corrosion or radiolytic processes, might be absorbed into the copper coating proposed for use as corrosion protection for the used nuclear fuel containers (UFCs) to be stored in a deep geological repository (DGR) in Canada. Hydrogen absorption may have the potential to alter the mechanical properties of the copper coating. This contribution discusses our initial study, using in situ neutron reflectometry (NR) and electrochemical impedance spectroscopy (EIS), of hydrogen absorption into a 50-nm layer of copper coated onto 4 nm of Ti on a Si single-crystal substrate. In situ NR-EIS experiments detected no increase in the hydrogen content within the copper layer of the copper-titanium thin film following 55 h of polarization in deoxygenated 0.1 M NaCl solution at pH 9, at potentials ranging from −444 mV/SCE to −1300 mV/SCE (detection limit ~2 at.%). However, these NR results showed that hydrogen can be absorbed into copper when the latter is cathodically polarized below about ─900 mV/SCE, which is the experimentally measured potential threshold for the hydrogen evolution reaction (HER) under these conditions. Although hydrogen did not accumulate in the outer Cu layer, our experiments revealed that the absorbed hydrogen quickly traversed the Cu layer to concentrate in the underlying titanium layer, which favours absorbed hydrogen. This observation is consistent with hydrogen uptake measured using inert gas fusion analysis on oxygen-free, phosphorus-doped (OFP) copper, which showed that in the absence of hydrogen recombination inhibitors (e.g., As(III)), only a small increase of 22 wt. ppm hydrogen was absorbed into the copper after 24 h at E = −1300 mV/SCE, and no increase in absorbed hydrogen occurred at potentials of −1100 mV/SCE or more positive. The initial absorption efficiency for electrolytically produced hydrogen atoms at the copper surface was determined to be 3.2%, suggesting that there may be an upper limit for hydrogen uptake by the copper coating of the UFC, although studies on 3 mm copper-coated steel samples representative of UFC materials will be required to confirm that. This result supports the prediction that hydrogen absorption is unlikely to lead to any failure of the copper barrier within a proposed DGR, in which it will not be possible to achieve such negative electrochemical potentials. Intended future research using in situ NR-EIS to study hydrogen absorption during the corrosion of copper thin films by HS⁻ ions and further studies on hydrogen absorption into 3-mm-thick copper-coated steel samples will help to validate these conclusions.

Improving fatigue initiation life of open-hole fibre metal laminates by laser shock peening

Although drilling open holes in fibre metal laminates reduces weight, it brings potential crack initiation sites. This paper investigates the effect of laser shock peening (LSP) on fatigue performance of open-hole titanium-based carbon-fibre/epoxy laminates (Ti-CF FMLs). A method based on multi-step simulation was proposed for the reconstruction of LSP induced residual stress field in open-hole Ti-CF FMLs. The results show that the fatigue initiation life of open-hole Ti-CF FMLs is improved by 22.1 %–81.0 % after LSP, depending on the structure of FMLs and the applied fatigue load. The improved fatigue crack initiation life attributes to compressive residual stress generated throughout the entire depth of the hole wall in outer titanium layer in Ti-CF FMLs after LSP. However, LSP leads to the formation of tensile residual stress far from the hole edge, resulting in accelerated propagation of fatigue crack. The fatigue initiation lives of open-hole Ti-CF FMLs before and after LSP were calculated by finite element simulation and theoretical method, showing good consistency.

Nanoscaled Titanium Oxide Layer Provokes Quick Osseointegration on 3D-Printed Dental Implants: A Domino Effect Induced by Hydrophilic Surface.

Three-dimensional printing is a revolutionary strategy to fabricate dental implants. Especially, 3D-printed dental implants modified with nanoscaled titanium oxide layer (H-SLM) have impressively shown quick osseointegration, but the accurate mechanism remains elusive. Herein, we unmask a domino effect that the hydrophilic surface of the H-SLM facilitates blood wetting, enhances the blood shear rate, promotes blood clotting, and changes clot features for quick osseointegration. Combining computational fluid dynamic simulation and biological verification, we find a blood shear rate during blood wetting of the hydrophilic H-SLM 1.2-fold higher than that of the raw 3D-printed implant, which activates blood clot formation. Blood clots formed on the hydrophilic H-SLM demonstrate anti-inflammatory and pro-osteogenesis effects, leading to a 1.5-fold higher bone-to-implant contact and a 1.8-fold higher mechanical anchorage at the early stage of osseointegration. This mechanism deepens current knowledge between osseointegration speed and implant surface characteristics, which is instructive in surface nanoscaled modification of multiple 3D-printed intrabony implants.