Tantalum Layer Research Articles

Highly Efficient Single Photon Coupling via Surface Plasmons into Single-Mode Optical Fiber

Quanta of light (single photon) play as one of the building blocks of photonic based quantum computations, sensing, and communications. This makes a necessity to develop practical approaches for tuning, guiding, and coupling of single photons in photonic circuits for viable applications. Interaction and coupling efficiency of single photon into optical fibers is a technical bottleneck of quantum optics and should be addressed by novel design and materials. Here, we introduce a fiber-based micro-photonic design to directly coupling of the emitted single-photon to the core of a single mode fiber (SMF). The results of the simulation indicate that the emission of single photon source on a D-shaped SMF coated by a thin plasmonic film, provide remarkable amplifying of the evanescent field by confined surface plasmons into the SMF. The numerical analysis of different types and thicknesses of plasmonic materials by finite element method (FEM) is conducted to study the propagation vectors along the SMF as a function of the emission angle and wavelength of the single photon source. The results revealed that by the optimum thickness of the tantalum layer as novel plasmonic material, the best record of coupling efficiency can be achieved in the fiber optics communication region (λ ∼ 1550 nm). This approach sheds light on novel plasmonic-assisted coupling and promises a functional strategy for single photon manipulation in various fields of quantum optics.

Flow boiling characteristics of HFE-7000 in high aspect ratio microchannels with the effect of flow orientation

The aim of the present experimental study is to investigate the flow boiling characteristics in a high aspect ratio microchannel for two different channel orientations. Hydrofluoroether 7000 (HFE-7000) flowing within a rectangular glass microchannel (with a hydraulic diameter of 909 μm and a width-to-height aspect ratio of 10) coated with a tantalum layer to provide uniform heating along the channel was the configuration investigated. The data were recorded for mass flux of 14 − 42 kg m−2 s−1, while the heat flux was varied between 3.5 and 24.3kWm−2 under horizontal and vertical upward flow. Analysis of the experimental data reveals that thermal performance is influenced by both mass and heat fluxes, as well as flow orientation, and these are presented and discussed. The wall temperature mapping and heat transfer coefficient analysis showed that for low mass flow cases, the dry out occurs at a lower heat flux and for either flow orientation. At medium and higher heat fluxes, though, it is found that a horizontal flow produces dry out events more easily compared to vertical upward flow. The observed phenomenon during flow boiling also shows the importance of nucleate boiling and thin film evaporation on the heat transfer performance. In addition, pressure fluctuations during flow boiling were also recorded. A Fourier transform analysis of pressure fluctuations data showed that vertical upward flow produces a higher dominant frequency than horizontal flow. Finally, the analysis of thermal characteristics and pressure fluctuations can provide further insights into the design of devices where flow orientation plays a major role.

Electrochemical reduction of tantalum and titanium halides in 1-butyl-1-methylpyrrolidinium bis (trifluoromethyl-sulfonyl)imide and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ionic liquids

The electrodeposition of tantalum-titanium–based films using different tantalum and titanium halides was investigated in two ionic liquids, namely, 1-butyl-1-methylpyrrolidinium bis (trifluoromethyl-sulfonyl)imide ([BMP][TFSI]) and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([BMP][OTf]). Cyclic voltammetry was used to analyse the electrochemistry of the electrolytes and potentiostatic deposition was performed to evaluate the feasibility of electrodepositing tantalum-titanium–based layers. Both the metal salts and the ionic liquid influenced the electrochemical reduction of the tantalum and titanium halides significantly. While titanium halides considerably retarded the reduction of tantalum pentahalides and inhibited electrodeposition in many electrolytes, an electrolyte composition from which tantalum and titanium-containing layers could be deposited was identified. Specifically, in TaBr5 and TiBr4 in [BMP][TFSI], TiBr4 did not inhibit the deposition of tantalum and titanium was co-deposited itself by a three-step reduction mechanism as confirmed by cyclic voltammetry and energy-dispersive X-ray spectroscopy. Furthermore, [BMP][TFSI] led to smoother and more compact deposits.

Improving the electrochemical corrosion behavior of stainless steel (316L) through the deposition of tantalum-based thin films

Austenitic 316L stainless steel (SS) is commonly used as a biomaterial for human implant applications. However, its clinical uses are limited due to its relatively high corrosion rate in physiological conditions. Various surface modifications, including coatings, have been developed to enhance its performance. In this study, a thin layer of Tantalum (Ta) was applied to the surface of 316L stainless steel using a DC Magnetron Sputtering (DCMS) system; the thickness of the coating varied from 1.504 to 6.083 µm, achieved by deposition times ranging from 15 to 60 min. The aim was to examine the electrochemical corrosion characteristics of the uncoated 316L SS and the Ta-coated 316L SS, followed by Potentiodynamic Polarization (PDP), Electrochemical Impedance Spectroscopy, and Open Circuit Potential tests. These tests were conducted for 10 min, 60 min, and 90 min to assess their performance over time. The PDP measurements took place in a simulated body fluid (SBF) at a pH of 7.8 ± 0.25 and a temperature of 40 °C, with varying coating durations. The PDP test outcomes revealed that the Ta-coated 316L stainless steel exhibited enhanced resistance to corrosion compared to the uncoated 316L stainless steel sample. The efficacy of Ta coatings on the 316L stainless steel samples was assessed through several techniques, including Optical microscopes, Energy Dispersive X-ray Spectroscopy, Scanning Electron Microscopy, and X-ray Photoelectron Spectroscopy. The findings from SEM and EDS verified the successful application of the Ta coating onto the stainless steel. The composition of the surface oxide film of Ta, the substrate, and the thickness of the coating were determined using the XPS technique, which confirms the effectiveness of the Ta coating in safeguarding 316L stainless steel against electrochemical corrosion, particularly for biomedical applications.

Combined x‐ray reflectivity and grazing incidence x‐ray fluorescence study of Ta/Cr/Pt thin film stacks

AbstractThe Ta/Cr/Pt three‐layer system can be used as a planar x‐ray waveguide, that is to say it can guide an x‐ray beam inside its chromium layer. This property comes from the difference in density and hence in optical index between the two “heavy” or cladding tantalum and platinum layers and the “light” or guiding chromium layer. The waveguide will be efficient provided the layers are a few nanometers thick and that the interfaces are as sharp as possible. To control the quality of the stack, we combine grazing incidence x‐ray fluorescence (GIXRF) and x‐ray reflectivity (XRR) measurements on a series of Ta/Cr/Pt samples, whose only difference is the thickness of the Cr layer. The three considered samples have been deposited by magnetron sputtering and their designed structures are: Ta (8 nm)/Cr (5, 10, and 15 nm)/Pt (14 nm)/Si substrate. The combination of XRR and GIXRF tightens constraints on the parameters used to simulate the stack: thickness, roughness, composition, and density of the layers and their interlayers. For each sample we used six GIXRF curves obtained from three different characteristic x‐ray lines (Ta Lα, Cr Kα, and Pt Lβ2,15) excited at three different incident photons energies (6.25, 10, and 12 keV) as well as one XRR curve obtained at 6.25 keV. The XRR‐GIXRF combined analysis demonstrates that the Ta/Cr/Pt structure is too simplistic and that it is necessary to introduce some interlayers at the top and bottom of the stacks to obtain a reliable agreement between the experimental and simulated GIXRF and XRR curves.

Experimental investigation of bubble dynamics and flow patterns during flow boiling in high aspect ratio microchannels with the effect of flow orientation

Multiphase flow and boiling phase-change within microchannels are of paramount importance to thermal management and electronics cooling, among others. The present experimental study investigated the bubble dynamics and flow patterns during flow boiling in a high aspect ratio microchannel at different channel orientations. Hydrofluoroether (HFE−7000) was used as the working fluid within a transparent glass microchannel with a width-to-height aspect ratio of 10 and a hydraulic diameter of 909 μm. A tantalum layer coating was applied to the channel, allowing visual observation to be conducted whilst imposing uniform heating along the channel. Under horizontal and vertical upward flow, the mass fluxes were varied between 14 kg m−2 s−1 and 42 kg m−2 s−1 for Reynolds numbers between 28.4 and 85.2, while the heat fluxes were set from 2.8 kW m−2 to 18.7 kW m−2. The results show that single bubble growth can be divided into three stages, namely: bubble-free growth, partially confined bubble growth, and fully confined growth. The effects of mass flux and heat flux on bubble behaviour and transition points between the defined stages are discussed. Equally important, the channel orientation influences the bubble behaviour in terms of bubble evolution, bubble shape, and bubble nose velocity, with no significant differences observed for the flow patterns when comparing horizontal and vertical upward cases. The comparison of the present work with previous flow pattern map results from the literature shows that earlier flow pattern transition models cannot accurately predict the observed flow patterns in the present configuration. Two types of instabilities are observed, which are associated with the dominant flow pattern during flow boiling and hence a function of the mass flux to heat flux ratio. The first type of instability, high amplitude and long period oscillation, is found during slug flow which is characterised by the presence of bubble rapid expansion along the channel. In addition, a second instability ensues when churn and annular flow create short period oscillations due to the high number of nucleation events, bubble coalescence, and the breakage of liquid slug or liquid film.

Design and Development of Tantalum and Strontium Ion Doped Hydroxyapatite Composite Coating on Titanium Substrate: Structural and Human Osteoblast-like Cell Viability Studies.

In order to reduce the loosening of dental implants, surface modification with hydroxyapatite (HA) coating has shown promising results. Therefore, in this present study, the sol-gel technique has been employed to form a tantalum and strontium ion-doped hybrid HA layer coating onto the titanium (Ti)-alloy substrate. In this study, the surface modification was completed by using 3% tantalum pent oxide (Ta2O5), 3% strontium (Sr), and a combination of 1.5% Ta2O5 and 1.5% Sr as additives, along with HA gel by spin coating technique. These additives played a prominent role in producing a porous structure layer coating and further cell growth. The MG63 cell culture assay results indicated that due to the incorporation of strontium ions along with tantalum embedded in HA, cell proliferation increased significantly after a 48 h study. Therefore, the present results, including microstructure, crystal structure, binding energy, and cell proliferation, showed that the additives 1.5% Ta2O5 and 1.5% Sr embedded in HA on the Ti-substrate had an optimized porous coating structure, which will enhance bone in-growth in surface-modified Ti-implants. This material had a proper porous morphology with a roughness profile, which may be suitable for tissue in-growth between a surface-modified textured implant and bone interface and could be applicable for dental implants.

Tantalum-containing coatings with superhard inclusions produced by DC-magnetron sputtering

A tantalum-containing two-layer coating consisting of a 50 nm thick tantalum oxide sublayer and a tantalum layer up to 1200 nm thick has been produced by DC-magnetron sputtering. On the surface of the coating grains, disoriented lamellar formations with an average size of 46 ± 1 nm were found, the hardness of which was characterized by a bimodal distribution. The proportion of superhard inclusions with H = 76.19 ± 9.64 GPa was no <55.6%.

A Study on the Microstructure Development in Laser-Cladded Tantalum Layers

A Study on the Microstructure Development in Laser-Cladded Tantalum Layers

Optical Properties of Valve Metals Functional Thin Films Obtained by Electrochemical Anodization on Transparent Substrates

Nanostructured aluminum, tantalum, and vanadium oxide layers on glass substrates were obtained by electrochemical anodizing in oxalic and sulfuric–oxalic electrolytes. The morphological and optical properties of the obtained structures were investigated experimentally by scanning electron microscopy and transmission spectroscopy. Obtained oxide coatings are quasi-ordered arrays of vertical (aluminum oxide/tantalum oxide, aluminum oxide/vanadium oxide, and aluminum oxide obtained in the oxalic electrolyte) or non-ordered tree-like (aluminum oxide obtained in the sulfuric–oxalic electrolyte) pores depending on the initial film metal and anodizing technology. The light transmission in the range of 750–1200 nm is up to 60% for aluminum oxide/tantalum oxide/glass (annealed) and quasi-ordered aluminum oxide/glass structures, and around 40% for aluminum oxide/tantalum oxide/glass (not annealed) and aluminum oxide/vanadium oxide. Non-ordered aluminum oxide is characterized by low transmission (no more than 8%) but has a developed surface and may be of interest for the formation of films with poor adhesion on smooth substrates, for example, photocatalytic active xerogels. The refractive indices of dispersion of the obtained layers were calculated from the transmission spectra by the envelope method. The dispersion of the refractive indices of the obtained oxide films is insignificant in a wide range of wavelengths, and the deviation from the average value is assumed to be observed near the intrinsic absorption edges of the films. The glasses with proposed semi-transparent nanostructured oxide layers are promising substrate structures for subsequent sol–gel coating layers used in photocatalytic purification systems or up-conversion modules of tandem silica solar cells with forward and reverse illumination.

Modification of the mechanical properties of Ti/Ta multilayer composites with heterogeneous lamella structure

Multilayer composites are promising to improve the comprehensive mechanical properties of conventional metals. In this study, a series of Ti/Ta multilayer composites with different thickness ratio between titanium layer and tantalum layer are prepared. The relationship between microstructure and mechanical properties of these Ti/Ta multilayer composites is investigated. It has been found that heterogeneous lamella structure, including α + β titanium layer, pure β‑titanium layer ana tantalum layer, is developed in these composites. The volume fraction of α + β titanium layer and tantalum layer decreases and the volume fraction of β‑titanium increases with the increase of bonding temperature. The composites bonded at 1300 °C has got the best comprehensive mechanical properties. Furthermore, the mechanical properties of the composites can be modified by adjusting the thickness ratio between titanium layer and tantalum layer. The mechanical properties of Ti/Ta30 multilayer composites are much better than that of Ti/Ta100 multilayer composites. The fracture morphology of the Ti/Ta multilayer composites prepared at different bonding temperatures are similar. However, the fracture morphology of tantalum layer and titanium layer are different. And a fracture mode is proposed.

THE DEFORMATION VALUE EFFECT ON THE TA-W-TA SOLID-PHASE JUNCTION NATURE WITH INTERMEDIATE TI (TITANIUM) INTERLAYERS FOR THE NEUTRON PRODUCING TARGET OF THE NEUTRON SOURCE

The paper presents the quality studies results of the Ta-W-Ta solid phase junctions with Ti interlayers obtained by hot roll bonding in vacuum, that determine the work suitability in the form of neutron producing targets at the research nuclear facility ‘Source of Neutrons’. It is shown the layers mutual penetration level of the Ta-W-Ta solid-phase junction with Ti interlayers which provides a high level of clad layers adhesion when using the hot vacuum roll bonding method. The deformation parameters necessary both for the solid phase bond occurrence and for the reliable solid-phase junction formation of tantalum and tungsten refractory metals layers through a titanium interlayer, with a joint strength exceeding the value of a less durable material are determined. The possibility of chemical vapor deposition (CVD) method using for side faces coating of targets was studied.

P‐18: Student Poster: Low Voltage Oxide Transistor with High Dielectric Tantalum Oxide Gate Insulator by Thermal Oxidation of Tantalum

Low voltage oxide thin film transistor (TFT) was developed using high dielectric gate insulator by thermal oxidation of tantalum metal. Thermal oxidation was carried out after deposition of tantalum layer by sputtering. Thermal grown tantalum oxide was analyzed by HR‐TEM and XPS. Through XPS analysis, it was confirmed that the binding energy of Ta4f indicates the formation of tantalum oxide. And the clear O1s peak has good Ta‐O bond. The transfer characteristic of the developed oxide transistor showed mobilities over 10 cm2/V·s and the inverter circuit operating below 1 V was achieved.

Fatigue life and cyclic creep of tantalum/copper/steel layerwise plates under tension loading at room temperature

The unique properties of tantalum make it extremely desirable in demanding branches of industry. Its limited availability necessitates its efficient use. High efficiency can be achieved by producing layerwise-heterostructured plates with a tantalum layer. However, the exposure of this composite to fatigue loading is being questioned because it has never been tested under such conditions. The purpose of this study was to investigate the fatigue behavior of an explosively manufactured composite with an outer tantalum layer under cyclic loading. The microcracks that developed along the slip lines in the grains of the tantalum layer were found and identified as the initial damage mechanisms that led to cyclic creep. The composite plates exhibited superior fatigue strength compared with the homogenous tantalum plate.

Overview of CSNS tantalum cladded tungsten solid Target-1 and Target-2

A solid tungsten target was used at the China Spallation Neutron Source (CSNS) with 100 kW proton beam power. To improve the lifetime, hot isostatic pressing (HIP) process was selected to bond tantalum cladding with tungsten plates. Radioactive isotope 182Ta, an activation product of tantalum, was found in the cooling water after a period of operation, however, no radioactive isotopes of 187W was found, which shows the tantalum layer remained mostly intact. The CSNS Target-1 had been operating safely for three years and was replaced by Target-2 in August 2020.

Electrodeposition of Tantalum Coatings on Nitinol Stent and Composition of Intermetallic Compounds Forming During Electrolysis

The electroreduction of tantalum complexes in a chloride-fluoride melt was studied on tungsten, and nitinol electrodes. It was found that on a nitinol electrode in addition to the peak associated with the discharge of fluoride tantalum complexes, several peaks on the voltammogram related to the formation of intermetallic compounds of nickel and tantalum were observed. The electrodeposition of tantalum coatings from the NaCl-KCl-NaF(10 wt.%)-K2TaF7(10 wt.%) melt onto nitinol stent was investigated. The formation during electrolysis of several intermediate layers between the deposited layer and substrate was found and their microstructure and chemical composition were determined. It was determined that the surface layers of the nitinol are depleted in titanium due to corrosion in the melt. During electrodeposition a barrier intermetallic layer TiNi2.4Ta0.6 is formed, which prevents the penetration of tantalum into the substrate, but does not prevent the diffusion of nickel and titanium from the substrate into the deposited layer of tantalum.

Advance of CSNS Solid Target

A 100 kW solid target was successfully developed for the CSNS phase one. Tungsten was selected as the CSNS target material and a layer of tantalum with a thickness of only 0.3mm as a protective layer. Eleven target blocks were fixed in parallel in a stainless steel target container with 1.2mm gap between each block. Using a specially designed spreader, the target plug can be easily replaced. The parameters of the target were stable and normal in the course of more than a year of operation, the temperature rise of the target cooling water inlet and outlet increased as the proton beam power increased.

Functionalization of Contacted Carbon Nanotube Forests by Dip Coating for High‐Performance Biocathodes

AbstractThis work focuses on the use of electrically contacted carbon nanotube forests as an electrode material for the bioelectrocatalytic reduction of oxygen to water. The forests are directly grown by chemical vapor deposition on a conductive tantalum layer, which provides enough mechanic stability during several functionalization and enzyme immobilization steps. A pyrene bis‐anthraquinone derivative (pyr‐(AQ)2) was attached via π‐stacking throughout the forest and was used as an anchor molecule for oriented immobilization of laccase. This led to high‐performance biocathodes for oxygen reduction via direct electron transfer with absolute maximum current densities up to 0.84 mA cm−2 at 0.2 V vs Ag/AgCl. The morphological changes during the wet chemical processes were studied by scanning electron microscopy (SEM) revealing cellular patterning of the forest structure. Despite these changes, the forest remained attached and electrically connected to the tantalum layer. The resulting bioelectrodes performed with satisfying stabilities under constant discharge conditions and kept 75 % of its initial performances after one week.

Nanoporous metal-polymer composite membranes for organics separations and catalysis.

Metallic thin-film composite membranes are produced by sputtering metal films onto commercial polymer membranes. The separations capability of the membrane substrate is enhanced with the addition of a 10 nm Ta film. The addition of a tantalum layer decreases the molecular weight cutoff of the membrane from 70 kDa dextran (19 nm) to below 5 kDa (6 nm). Water flux drops from 168 LMH/bar (LMH: liters/meters2/hour) (polymer support) to 8.8 LMH/bar (Ta composite). A nanoporous layer is also added to the surface through Mg/Pd film deposition and dealloying. The resulting nanoporous Pd is a promising catalyst with a ligament size of 4.1 ± 0.9 nm. The composite membrane's ability to treat water contaminated with chlorinated organic compounds (COCs) is determined. When pressurized with hydrogen gas, the nanoporous Pd composite removes over 70% of PCB-1, a model COC, with one pass. These nanostructured films can be incorporated onto membrane supports enabling diverse reactions and separations.

Graded microstructure and texture in ultrafine grained multi-layered immiscible bimetallic system

In this investigation we report the formation of a graded microstructure in copper/tantalum ultrafine grained (UFG) multi-layered composite fabricated by cross accumulative roll bonding (CARB) process at high temperatures. The microstructure, micro-texture and bulk texture evolution in the copper/tantalum composite was established. A gradient microstructure develops along the thickness of the specimen during the CARB process. The fragmentation of tantalum in between copper layers and the grain refinement with evolving passes has been explained. The deformed copper layers show rotated cube texture and deformed tantalum layers show cube texture with γ-fibre. The overall texture of copper/tantalum composite weakens after the process of ARB; copper undergoing texture randomization post annealing. The crucial role of interfaces on the evolution of texture is demonstrated. The microstructural gradient in the specimen possess equiaxed, lamellar as well as large deformed grains with tantalum's grain size being in the scale of 200 nm. The correlation of microstructural gradient with orientation relationship (OR) between copper and tantalum layers was studied, confirming higher misorientation in OR at regions under high strain. Dynamic recrystallization taking place at the copper/tantalum interface has been elaborated with the aid of microtexture analysis.