Ti Sheet Research Articles

Characterization of titania self-aligned nanotubes prepared under various conditions for the photoelectrochemical water splitting

TiO2 nanotubes were grown by anodization of Ti sheets in an ethylene glycol solution. The then prepared nanotubes were tested with and without heat treatment at 450 ºC, for the water splitting process. The heat treatment produced increased photocurrent from 4.9 µA cm−2 to 56.8 µA cm−2 under illumination at 0.7 V vs. SHE. Modification of the nanotubes was carried out by electroreduction on both heat treated and untreated samples and its photoactivity evaluated. The spectral response showed increased photocurrent for the reduced material (black titania), although no appreciable change was detected in the absorbed spectra for the visible wavelengths. Finally, high-purity (> 99.6%) and commercially pure (99%) Ti sheets were used to grow TiO2 nanotubes with no clear difference in photocurrents (61.5 µA cm−2 vs. 65.4 µA cm−2 while illuminated at 0.7 V vs. SHE) showing the potential for cheap commercialization.

Texture development of pure Ti by rolling at various temperatures and its effect on sheet formability

This work investigated the effect of rolling temperature (25–800 °C) on rolling-texture development and sheet formability of pure Ti. The rolling temperature significantly affected the development of the typical transverse-direction (TD)-split basal texture in pure Ti sheet by altering the tilting angle of (0001) basal poles. Notably, a normal-direction (ND) basal texture, where the tilting angle of (0001) basal poles was approximately 0°, developed at an intermediate rolling temperature of 400 °C. This result is remarkable because the ND basal texture is rare in pure Ti. Formation of this unusual ND basal texture was attributed to significant activation of basal <a> slip. In contrast, a typical TD-split basal texture was dominant at the other rolling temperatures. Formation of this typical texture was attributed to pyramidal <c+a> slip. After subsequent recrystallization annealing, sheet formability was examined. Despite their different textures, the sheets previously rolled at the different rolling temperatures showed similar formability. This similarity occurred because any given texture could not simultaneously provide in-plane stretching uniformity and thinning capability during sheet forming. The present study suggests an important guidance for modifying texture of pure Ti sheets to effectively increase their formability.

Engineering a High Stable and Active RuO2 on Ti Sheet for Kolbe Electrolysis of Acetic Acid: An Investigation to Valorize the Pyroligneous Acid

The efficient utilization of renewable sources based on the simultaneous production of energy fuels and value-added chemicals is an essential to enable a biobased circular economy that benefits carbon neutrality. As an abundant by-product during the pyrolysis of biomass, pyroligneous acid is rich in acetic acid (CH3COOH) that is difficult to handle due to its highly acidic content. However, it is essential made up of renewable carbon that can be converted into valuable chemicals and fuels (e.g. methane, ethane, propane). Herein, we fabricate a highly stable and effective ruthenium oxide electrocatalyst (RuO2/TiOx) via using available titanium sheet as the substrate, to highly selectively transform AA to ethane by electrochemical conversion with ~82 (±5)% selectivity. The obtained results demonstrate that RuO2/TiOx exhibits an efficient electrochemical performance at low temperatures (5℃), and can convert AA at various pH, current density, and different concentrations. Moreover, we mimicked the complex chemical environment of the pyroligneous acid by adding diverse hydrocarbons (e.g., phenols, aldehydes) in acid solution to evaluate the stability of RuO2/TiOx. The electrolysis was also conducted in original pyroligneous acid solution, in which the RuO2/TiOx exhibits a considerable performance to convert AA to ethane. This work, based on the selective production of ethane from AA by a RuO2/TiOx electrode as an alternative to bulk metals as anodes for oxidative upgrading of carboxylic acids, making it promise to directly turn biomass residual into fuel thus improve the biomass utilization.

Grain refinement and phase precipitation simultaneously improve the strength and ductility of ultra-high strength titanium alloy sheets

The simultaneous high strength and high plasticity of metastable-β titanium alloy sheets remains a difficult challenge. In this work, a 1.2 ​mm thick sheet of Ti–15Mo–3Al-2.7Nb-0.25Si titanium alloy was obtained after rolling and annealing, and then subjected to a duplex-ageing treatment. The pre-ageing temperatures fell in the range of 300–390 ​°C for 0.5–2h. The re-ageing temperatures were in the range of 500–600 ​°C. After characterization, it was found that the alloy precipitates ω-phases during the pre-ageing process, and the distribution of such ω-phases evolves unevenly and increases in number with the increase of the pre-ageing temperature. Therefore, the strengthening mechanism of the alloy sheet is mainly α-phase nucleation assisted by ω-phase. Moreover, grain refinement appears as a mechanism to ensure the plasticity of the alloy. Finally the ω-phase evolution law is discussed in detail and the strengthening mechanism of the alloy sheet is also analyzed. At this work, a metastable-β titanium alloy sheet with strength of 1445.75 ​MPa and elongation of 6.55 ​% was obtained. This study provides a new idea for the microstructure design and process improvement of the metastable-β titanium alloy sheet.

Electropulsing anisotropy of cold-rolled Grade 2 titanium sheet: Effect of electric current direction on recrystallization and hardness

This study investigated the effects of electropulsing treatment (EPT) condition on the microstructure and microhardness of cold-rolled Grade 2 Ti sheet. Particular attention was paid to the dependence of the material properties on the electric current direction, referred to as electropulsing anisotropy. Direct-current (DC) EPT was applied along either the rolling direction (RD) or transverse direction (TD) of the rolled sheet. EPT along the TD resulted in a higher heating rate and maximum temperature, whereas that along the RD accelerated the static recrystallization (SRX) process under identical electropulsing parameters. Such a discrepancy was interpreted using the elongated grain structure and basal texture in the cold-rolled Ti sheet. These results were further supported by microhardness measurements, confirming the presence of electropulsing anisotropy during DC EPT in Ti alloys for the first time. In addition, the employed EPT was compared to a traditional furnace heat treatment (FHT) with rigorous temperature and time control, wherein the optimum EPT process spent only 13% of the processing time to complete SRX with a lower thermal energy requirement. This indicates a significant athermal contribution of EPT to electropulsing anisotropy.

Development of a high-capacitance flexible supercapacitor with enhanced cycling stability based on nanotubular polyaniline-modified titanium sheet

Nanotubular polyaniline modified titanium (PANI/Ti) sheet was synthesized via one-step chemical polymerization of aniline on a Ti sheet. The structural and morphological investigations of the PANI/Ti sheet were performed using X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. These investigations revealed that a nanotubular PANI network with an average diameter of 37.5 nm was vertically aligned on the Ti sheet. Electrochemical properties of PANI/Ti were investigated via cyclic voltammetry, galvanostatic charging/discharging, and electrochemical impedance spectroscopy in a three-electrode system. The PANI/Ti sheet exhibited an exceptional specific capacitance (Csp) of 1174 mF/cm2 at 2 mA/cm2, which was significantly higher than that of the PANI/GC (199.53 mF/cm2) and the bare Ti sheet (0.87 mF/cm2). The prepared PANI/Ti sheet exhibited a power density of 21.99 mW/cm2 at an energy density of 3.05 mWh/cm2. Moreover, the electrode demonstrated outstanding cycle stability, maintaining 97.62% efficiency over 3000 cycles and exhibited impressive flexibility, with minimal performance degradation even when bent at angles up to 90°. Furthermore, PANI/Ti sheet significantly reduces the solution and charge transfer resistance compared to bare Ti sheet. So PANI-modified Ti sheet will be a good choice for the fabrication of new flexible energy storage as well as electronic devices in the future.

Improving interfacial strength at room and elevated temperatures in ultrasonic welding of pure titanium: Interlayer-induced phase transformation and concentrated plastic deformation

Ultrasonic welding (USW) of Titanium (Ti) sheets presents several challenges, notably crack formation due to sliding friction. To overcome this problem, the present study applied USW to pure α-Ti sheets both with and without different interlayer metals (Al, Ni, and Fe). Al interlayer improved the strength at room temperature significantly to cause base metal fracture (1700 N) by inducing concentrated plastic deformation, facilitating bonding with Ti while minimizing damage. However, its strength decreased significantly at 150–300 °C, suggesting the limitation of using Al interlayer at elevated temperatures. Conversely, the Ni and Fe interlayers led to a two-phase strength development. This enhancement was due to β-phase transformation, which reduces the interfacial defects and generates a more pronounced β-stabilization effect. The Ni interlayer, which has a higher β-transus point (765 °C) and lower molybdenum equivalency, required a higher welding energy (1800 J) and longer diffusion time into Ti, resulting in a gradual increase in strength due to a slower β-Ti transformation. On the other hand, the Fe interlayer with a lower β-transus point relative to Ti (595 °C) achieved peak strength at a lower welding energy of 1200 J. Both Fe and Ni interlayers displayed only a slight decrease in strength (1500–1600 N) at 300 °C with base metal fracture, revealing better joint performance at higher temperatures. These insights suggest a strategical interlayer selection based on the operation temperature, where Al interlayers were advantageous for low-energy welding at room temperature application, Fe and Ni interlayers offer sufficient strength at elevated temperatures by facilitating the β-Ti formation.

Improved Electrocatalytic Degradation of Alizarin Yellow R by Ti/Zr-SnO2/PbO2 Electrodes Doped with Ytterbium

Introduction: Electrochemical oxidation of Alizarin Yellow R (AYR) was investigated on Ytterbium (Yb) doped Ti/PbO2 electrodes prepared by an electrodeposition method. Method: The etching of the Ti sheet by using a mixed acid of H2SO4 and TA (volume ratio= 2: 1) for 50 min at 100 °C could produce a suitable interface for further modification. The morphologies, composition, and electrochemical properties of Yb doping on the electrode were characterized by SEM (Scanning Electron Microscopy), EDS (Energy-Dispersive Spectroscopy), Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The introduction of an appropriate intermediate layer, Zr-SnO2, was performed. We also tried to fabricate Ytterbium (Yb) doped Ti/Zr-SnO2/PbO2 electrodes by an electrodeposition method on the intermediate layer of Zr-SnO2. The surface morphology of the Ti/Zr-SnO2/PbO2 electrode was changed due to the Yb doping, which affected the electrocatalytic activity of the modified electrode. Result: The developed Yb-doped Ti/Zr-SnO2/PbO2 electrode showed improved removal efficiencies toward AYR. Conclusion: The effects of current density and initial AYR concentration on the electrochemical oxidation of AYR by Yb-doped Ti/Zr-SnO2/PbO2 were investigated. The removal rate of AYR was 97.3% in 180 min under the conditions of the current density of 60 mA/cm2 , initial AYR concentration of 50.0 mg L-1 , and Na2SO4 concentration of 0.10 mol L-1 .

Effect of microalloying with rare-earth lanthanum on dynamic recrystallization behavior and mechanical properties of Ti sheets

This study examines the influence of microalloying with rare earth lanthanum (La) on the dynamic recrystallization behavior and mechanical properties of Titanium (Ti) sheets. A distinctive wedge-shaped specimen was employed for experimental efficiency, enabling continuous gradient strains to be applied to the Ti-La alloy during hot-rolling, facilitating the assessment of changing microstructural, textural, and hardness features as strain increased from low to high levels. The hot-rolled plates were performed using analytical methods such as optical microscopy (OM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and hardness testing. The results show that the hardening process can be divided into four stages under continuous gradient strain (0 ∼ 0.5, 0.5 ∼ 0.7, 0.7 ∼ 1.2 and 1.2 ∼ 1.6). During these stages, grain refinement and dislocation strengthening emerge as critical contributors to changes in hardness. Furthermore, it was determined that dynamic recrystallisation (DRX) of Ti-La alloys during hot rolling occurs at the fourth stage. Analysis of the orientation distribution function (ODF) reveals that the dominant textures during this process include {1̅21̅0}, {011̅0}, and {0001} textures. When compared with commercially pure titanium (CP-Ti), the Ti-La alloy shows significantly delayed DRX under identical conditions. The DRX grain growth appears suppressed, attributable to the presence of La-rich particles on the grain boundaries. Moreover, the texture associated with rolling deformation seems subdued, providing a desirable base for future cold rolling and heat treatment.

Portable and highly enhanced surface enhanced Raman scattering and photocatalytic activity of cost-effective hierarchical hollow metal organic frameworks heterostructures induced by etched titanium sheet

In order to effectively detect and remove organic toxics in wastewater, the facile construction of plug and play bifunctional materials is very vital. Herein, a kind of metal-organic frameworks (MIL-53 (Fe) with hollow tubular structure was induced by an etched Ti sheet (ET), and then small sized Ag nanoparticles (Ag NPs) were in-situ anchored evenly on the internal and external surfaces of MIL-53 (Fe). Subsequently, a new type of bifunctional material (ETMA) was assembled. Surface enhanced Raman scattering (SERS) and photocatalytic activity of the material were investigated with crystal violet (CV, a carcinogenic and teratogenic toxic) as an analyte. The results found that trace amount of CV (1 × 10−12 M) can still be sensitively detected by the fabricated ETMA, and analysis enhancement factors as high as 6.9 × 105 even though only 1.39 wt % Ag was contained in the ETMA. Moreover, nearly 100 % of CV can be rapidly degraded by the ETMA after irradiated for 15 min, which was 44.47 times and 7.27 times faster than those of ET-Ag (ETA) and ET-MIL-53 (Fe) (ETM), respectively. Additionally, the removal efficiency of total organic carbon (TOC) was as high as 75.44 %. The remarkable enrichment effect, the strong interaction among components, and the synergistic effect in the target ETMA material were responsible to the dramatically enhanced SERS and photocatalytic performances. In addition, the cost-effective ETMA exhibited excellent uniformity, repeatability, stability, and recyclability towards the detection and removal of CV in actual water samples, showing great potentials in monitoring and removing organic pollutants in practical ecological environment.

Laser deposition of titanium layer to enhance two-way shape memory behavior of Nitinol sheet

One of the long-standing mechanical challenges associated with shape memory alloys (SMAs) is achieving and stabilizing an evolving two-way shape memory effect (TWSME) through thermomechanical training/cycling. In most martensitic NiTi SMAs that exhibit zero TWSME at room temperature, the TWSMEs typically require hundreds of cycling repetitions to track trivial values. This demonstrates a promising solution to overcome this challenge. The surface of NiTi SMA sheets was treated by depositing a certain number of titanium (Ti) powder layers on the NiTi surface using a laser beam. The results showed that a unique TWSME of approximately 12% with good stability was achieved after 100 cycles when the optimum number of five Ti layers was deposited, which was much higher than that of the NiTi sheet (0.3% TWSME) and the sample with a single-time laser path irradiation (1.8%). This was attributed to the low coefficient of thermal expansion of the Ti vs. NiTi sheet, which prevented reverse bending during heating, and the formation of Ti-rich intergranular Ti2Ni(Ox) precipitates, which hindered dislocation movement. Meanwhile, in this sample, owing to the generation of a large residual tensile stress and a large heat-affected zone that led to a reduction in plastic zones, the one-way shape memory effect (OWSME) was retained at values above 90% with good stability over cycling. However, the introduction of additional Ti layers can cause problems in terms of oxygen accumulation within the NiTi sheet, which should be considered when designing a product.

Improved cell growth on additively manufactured Ti64 substrates with varying porosity and nanofibrous coating

3T3 Swiss albino mouse cells are often used in biotechnological applications. These cells can grow adherently on suitable surfaces. In our study, they were grown on different titanium substrates, comparing commercially available titanium sheets of grade 1 and grade 2, respectively, with Ti64 which was 3D printed with different porosity in order to identify potential substitutes for common well-plates, which could - in case of 3D printed substrates - be produced in various shapes and dimensions and thus broaden the range of substrates for cell growth in biotechnology and tissue engineering. In addition, thin layers of poly(acrylonitrile) (PAN) nanofibers were electrospun on these substrates to add a nanostructure. The common titanium sheets showed lower cell cover factors than common well plates, which could not be improved by the thin nanofibrous coating. However, the Ti sheets with nanofiber mat coatings showed higher cell adhesion and proliferation than pure PAN nanofiber mats. The 3D printed Ti64 substrates prepared by laser metal fusion, on the other hand, enabled significantly higher proliferation of (66±8)% cover factor after three days of cell growth than well plates which are usually applied as the gold standard for cell cultivation ((48±11)% cover factor under identical conditions). Especially the Ti64 samples with higher porosity showed high cell adhesion and proliferation. Our study suggests investigating such porous Ti64 samples further as a potential future optimum for cell adhesion and proliferation.

Formation of Pores on Pure Ti in Highly Concentrated Sulfuric Acids

TiO2 nanotubes formed by anodization in fluoride-containing electrolytes have been extensively examined due to their wide rage of applications. It is reported that fluoride ions move faster to the interface between anodic oxide layer and underlying Ti substrate, forming a fluoride-rich layer at the interface as the ionic radius of fluoride ion is smaller compared to that of oxygen ion. The fluoride-rich layer is also reported to decrease the adhesion of the anodic oxide layer to the substrate. Therefore, the formation of nanotubular oxide layer in fluoride-free electrolytes is highly desired. In the present work, we examined the formation of nanotubular oxide layers on pure Ti in highly concentrated sulfuric acids. Specimens with the dimension of 5 mm x 80 mm x 0.6 mm were prepared from pure Ti sheet (purity ; 99.5%). Prior to anodization, the specimens were cleaned in acetone, methanol and deionized water, successively. Anodization was carried out in highly concentrated sulfuric acids at elevated temperatures using two-electrode configuration cell with platinum counter electrode. The applied voltage was increased with the sweep rate of 1 V/s to desired voltages and then kept at the voltages for various durations. After the anodization, the surface of the specimens was cleaned with deionized water and dried. The structure of the surface was evaluated using FE-SEM. In a highly concentrated sulfuric acid, the anodic current increased with increasing the applied voltage and after switching constant voltage, decreased with time. The formation of oxide layer was confirmed at the surface, but no porous structure was visible. However, a porous structure was observed on the specimen above the electrolyte surface, indicating that the anodization occurred under the meniscus consisting of highly concentrated sulfuric acids. The optimization of water concentration in sulfuric acid and temperature led to the formation of porous structure on pure Ti. This indicates that porous oxide layers can be formed in fluoride-free electrolytes although further optimization is required to improve the ordering of pores.

Experimental and simulation analysis of the effect of GNPs on the mechanical and interfacial properties of CF/PEEK-Ti fiber metal laminates

In this study, graphene nanoplatelets (GNPs) were used to improve the interfacial and mechanical properties of carbon fibre-reinforced polyetheretherketone-based titanium alloy laminates (CF/PEEK-Ti) and molecular dynamics (MD) simulations were used to investigate the mechanism by which GNPs improve CF/PEEK-Ti, collectively known as fibre reinforced metal laminates (FMLs). In addition, surface anodising of titanium (Ti) sheets was used further to enhance the interfacial bonding properties of the FMLs. The experimental results showed that the flexural and shear strengths of the anodised FMLs were increased by 77.7% and 29.5%, respectively, compared with those of the Ti plates without surface anodisation. Based on this, different levels (0–1.5 wt.%) of GNPs were added to the FMLs matrix, and test results showed that FMLs containing 0.5 wt.% GNPs had the best flexural and shear strengths, 108.9% and 130.8% higher than untreated FMLs without GNPs. In addition, an in-depth microscopic analysis was carried out to understand the enhancement mechanism of GNPs on FMLs. Finally, MD simulations were used to analyze the role and mechanism of GNPs in this system. The results show that the addition of GNPs can increase the interfacial energy of FMLs. In other words, the interfacial mechanical properties of FMLs are improved. The effect of the dispersion of GNPs on the interfacial properties of FMLs was also investigated. The polyetheretherketone (PEEK) matrix could be significantly improved by well-dispersed GNPs. These findings provide insight into designing high-performing composites for various engineering applications.

Investigation on bacterial capture and antibacterial properties of acid-treated Ti surface

ObjectivesUtilizing Ti and Ti alloys as dental materials established a huge spurt in the field of dentistry. Since implantation is an invasive procedure that involves tissue penetration, infection control is mandatory for increasing the success rate of the implant treatment. In this study, we aimed to assess the impact of the surface physicochemical properties of acid-treated Ti on microorganisms specifically bacteria. MethodsAfter investigating the surface morphology and characteristics of acid-treated and untreated Ti sheets, we evaluated their potential to capture Escherichia coli (E. coli.) as well as the latter’s survival on the surface of both types of sheets. Finally, we assessed the efficiency of the antibacterial properties exhibited by Ti against the oral microflora. ResultsSEM images revealed surface roughening of the acid-treated Ti represented by significantly irregular shape. Moreover, the acid-treated Ti exhibited remarkable hydrophobicity. A quantitative evaluation confirmed that acid-treated Ti has higher bacterial capture and antibacterial properties than untreated Ti. Further experiments showed similar effects of both types of Ti not only on E. coli but also on oral microflora. SignificanceResults suggest that acid treatment of Ti surface is a potent technique for enhancing the antibacterial properties of Ti-derived materials.

Phase Transformations in Layered Composites Based on Zr, Nb, Ta or Ti Sheet Explosively Welded to Stainless Steel Plate

The composites based on reactive metals (Zr, Ta, Nb, Ti) sheets explosively welded to stainless steel plates were investigated using X-ray synchrotron radiation, TEM and SEM to characterize phase transformations in near-the-interface layers. SEM and TEM investigations of the solidified melt regions unveiled amorphous and nanocrystalline non-equilibrium phases of variable chemical compositions, incorporating elements from the joined components. Phase analysis in layers near the interface carried out using high-resolution synchrotron radiation show predominantly reflections coming from the main elements of parent sheets/plates. Nevertheless, a closer look at the diffraction patterns shows the presence of reflections coming from the phases based on the two-component equilibrium phase diagrams. The measurements performed at the interface, but including only the steel plate, revealed significant amounts of α-Fe, γ-Fe and ε-Fe phases. Their appearance was attributed to the high pressure and fast cooling rates, which promoted a martensitic transformation in steel.

Kalyuzhnyite-(Ce), NaKCaSrCeTi(Si8O21)OF(H2O)3, a new mineral from the Darai-Pioz alkaline massif, Tien-Shan mountains, Tajikistan: mineral description, crystal structure and a new double (Si8O21) sheet

AbstractKalyuzhnyite-(Ce), ideally NaKCaSrCeTi(Si8O21)OF(H2O)3, is a new mineral from the Darai-Pioz alkaline massif, Tien-Shan mountains, Tajikistan. It occurs as equant grains up to 0.05 × 0.07 mm in a quartz–pectolite aggregate in a silexite-like peralkaline pegmatite. Associated minerals are quartz, fluorite, pectolite, baratovite, aegirine, leucosphenite, neptunite, reedmergnerite, orlovite, sokolovaite, mendeleevite-(Ce), odigitriaite, pekovite, zeravshanite, kirchhoffite and garmite. The mineral is colourless with a vitreous lustre and a white streak, and Dcalc. is 3.120 g/cm3. Kalyuzhnyite-(Ce) is monoclinic, P2/c, a = 18.647(4), b = 11.214(2), c = 14.642(3) Å, β = 129.55(3)° and V = 2360.9(11) Å3. The chemical composition of kalyuzhnyite-(Ce) is Nb2O5 0.53, TiO2 0.16, SiO2 43.85, Er2O3 0.13, Ho2O3 0.10, Gd2O3 0.09, Sm2O3 0.47, Nd2O3 6.22, Pr2O3 1.21, Ce2O3 6.34, La2O3 0.82, PbO 4.90, BaO 0.85, SrO 11.39, CaO 1.86, Cs2O 3.80, K2O 1.59, Na2O 2.99, H2O 5.24, F 1.55, O = F –0.65, total 100.31 wt.%. The empirical formula calculated on 26.11 (O + F) apfu is Na1.07K0.37Cs0.30Sr1.21Ca0.37Pb0.24Ba0.06(Ce0.43Nd0.41Pr0.08La0.06Sm0.03Gd0.01Er0.01Ho0.01)Σ1.04(Ti0.97Nb0.04)Σ1.01Si8.06O25.21F0.90H6.42, Z = 4. The simplified formula is (Na,□)(K,Сs)(Ca,Pb,Sr,Na)SrLn3+Ti(Si8O21)OF(H2O)3, where Ce is the dominant lanthanoid. The crystal structure was solved by direct methods and refined to an R1 index of 2.74%. In kalyuzhnyite-(Ce), the main structural units are a heteropolyhedral Na–Sr–Ce–Ti sheet, ideally [NaSrCeTiOF]7+, and a double (Si8O21)10– sheet parallel to (010). In the Si–O sheet, the Si tetrahedra form ten-membered rings. This is the first occurrence of such a double Si–O sheet in a mineral. The two sheets connect via common vertices of Na-, Sr-, Ce- and Ti-polyhedra and SiO4 tetrahedra to form a framework. The interstitial cations and H2O groups, ideally [(CaK)(H2O)3]3+, occur within the Si–O sheet. The mineral is named in honour of Vasily Avksentievich Kalyuzhny (1899–1993) in recognition of his contributions to the geology of ore deposits of Komi Republic (USSR) and the mineralogy of granitic pegmatites (Tajikistan).

Near-infrared excited graphene oxide/silver nitrate/chitosan coating for improving antibacterial properties of titanium implants

To design and construct a graphene oxide (GO)/silver nitrate (Ag3PO4)/chitosan (CS) composite coating for rapidly killing bacteria and preventing postoperative infection in implant surgery. GO/Ag3PO4 composites were prepared by ion exchange method, and CS and GO/Ag3PO4 composites were deposited on medical titanium (Ti) sheets successively. The morphology, physical image, photothermal and photocatalytic ability, antibacterial ability, and adhesion to the matrix of the materials were characterized. The GO/Ag3PO4 composites were successfully prepared by ion exchange method and the heterogeneous structure of GO/Ag3PO4 was proved by morphology phase test. The heterogeneous structure formed by Ag3PO4 and GO reduced the band gap from 1.79 eV to 1.39 eV which could be excited by 808 nm near-infrared light. The photothermal and photocatalytic experiments proved that the GO/Ag3PO4/CS coating had excellent photothermal and photodynamic properties. In vitro antibacterial experiments showed that the antibacterial rate of the GO/Ag3PO4/CS composite coating against Staphylococcus aureus reached 99.81% after 20 minutes irradiation with 808 nm near-infrared light. At the same time, the composite coating had excellent light stability, which could provide stable and sustained antibacterial effect. GO/Ag3PO4/CS coating can be excited by 808 nm near infrared light to produce reactive oxygen species, which has excellent antibacterial activity under light.

Detection of the Oxidation Area by Spectrophotometry: Regional and Temporal Changes in Anodic Oxidation on Titanium in Bipolar Electrochemistry.

This study investigated the temporal change in the oxidation area on a titanium (Ti) bipolar electrode (BPE) subjected to bipolar anodization in a direct current (DC) electric field using a spectrophotometer. The rectangular Ti sheet used as a BPE was horizontally positioned at the center of a cell. After the DC bipolar anodization, the oxidized area was detected nondestructively and visually using a specific interference color that depends on the thickness of the barrier-type oxide film formed on the Ti BPE. The change in the L*a*b* color space corresponding to each interference color revealed that the oxidation area increased along the longitudinal axis of the BPE with the increasing electrolysis time by reflecting the change in the potential distributions on the BPE. As visually demonstrated, the area where the anodic reaction proceeded reached saturation at 90% of the BPE surface area.

Saturated Ti-coordinated {001} facets-dependent photocatalytic water reduction over NH2-MIL-125(Ti) sheets: Observation and unraveling of facets effect

Facets-dependent photocatalytic H2 evolution rates of inorganic semiconductors have been well recognized, but it remains unclear for metal-organic frameworks (MOFs). Herein, we controllably prepared a series of NH2-MIL-125(Ti) MOF sheets with different ratios of {001}/{111} facets exposure, on which the photocatalytic H2 evolution rates from water are demonstrated to be almost linearly increased with enhanced proportion of {001} facets. Notably, the optimized activity of ca. 2640 μmol h-1 g-1 is by far superior to all the NH2-MIL-125(Ti)-based photocatalysts reported. The discovery of facets-dependent photocatalytic water splitting performance (i.e. facets effect) was unravelled to mainly result from their distinct charge separation abilities according to the experimental facts that the saturated six-coordinated Ti atoms (Ti6c) in the {001} facets can more efficiently accept and store the photogenerated electrons by the reduction of Ti4+ into Ti3+ with respect to the low-coordinated Ti atoms (Ti4c and Ti5c) in the {111} facets.