Titanium Tungsten Research Articles

Application of quercetin and its bio-inspired nanoparticles as anti-adhesive agents against Bacillus subtilis attachment to surface

The aim of this study was directed to reveal the repulsive effect of coated glass slides by quercetin and its bio-inspired titanium oxide and tungsten oxide nanoparticles on physical surface attachment of Bacillus subtilis as an ab-initio step of biofilm formation. Nanoparticles were successfully synthesized using sol–gel and acid precipitation methods for titanium oxide and tungsten oxide, respectively (in the absence or presence of quercetin). The anti-adhesive impact of the coated-slides was tested through the physical attachment of B. subtilis after 24h using Confocal Laser Scanning Microscopy (CLSM). Here, quercetin was presented as a bio-route for the synthesis of tungsten mixed oxides nano-plates at room temperature. In addition, quercetin had an impact on zeta potential and adsorption capacity of both bio-inspired amorphous titanium oxide and tungsten oxide nano-plates. Interestingly, our experiments indicated a contrary effect of quercetin as an anti-adhesive agent than previously reported. However, its bio-inspired metal oxide proved their repulsive efficiency. In addition, quercetin-mediated nano-tungsten and quercetin-mediated amorphous titanium showed anti-adhesive activity against B. subtilis biofilm.

モリブデン，タングステンを含むチタン炭窒化物の熱伝導率と電気伝導率

モリブデン，タングステンを含むチタン炭窒化物の熱伝導率と電気伝導率

Process Parameters Optimization of 14nm MOSFET Using 2-D Analytical Modelling

This paper presents the modeling and optimization of 14nm gate length CMOS transistor which is down-scaled from previous 32nm gate length. High-k metal gate material was used in this research utilizing Hafnium Dioxide (HfO 2 ) as dielectric and Tungsten Silicide (WSi 2 ) and Titanium Silicide (TiSi 2 ) as a metal gate for NMOS and PMOS respectively. The devices are fabricated virtually using ATHENA module and characterized its performance evaluation via ATLAS module; both in Virtual Wafer Fabrication (VWF) of Silvaco TCAD Tools. The devices were then optimized through a process parameters variability using L9 Taguchi Method. There were four process parameter with two noise factor of different values were used to analyze the factor effect. The results show that the optimal value for both transistors are well within ITRS 2013 prediction where V TH and I OFF are 0.236737V and 6.995705nA/um for NMOS device and 0.248635 V and 5.26nA/um for PMOS device respectively.

Activating earth-abundant electrocatalysts for efficient, low-cost hydrogen evolution/oxidation: sub-monolayer platinum coatings on titanium tungsten carbide nanoparticles

Decorating titanium tungsten carbide nanoparticles with sub-monolayer platinum surface coatings yields efficient and stable catalysts for hydrogen evolution/oxidation reactions in acidic media.

Influence of Ti content on synthesis and characteristics of W–Ti ODS alloy

Tungsten–titanium alloys are considered as promising materials for the future fusion devices, in particular for the divertor and other first wall components. The microstructure and the mechanical properties of the material are dependent on the amount of Ti present in the alloy. In this study, W–Ti–Y2O3 alloys with varied Ti contents between 1 wt.% and 10 wt.% fabricated by mechanical alloying were investigated. The effect of Ti on the phase formation and mechanical properties of W–Ti–Y2O3 alloys has been examined. The results suggest that the alloys containing low Ti content exhibit homogeneous microstructure with a uniform distribution of fine titanium oxide particles and tungsten carbides, leading to a significant increase in hardness and elastic modulus of alloys. In addition, high-energy ball milling can facilitate a solid-state reaction between Y2O3 particles and the tungsten–titanium matrix and the subsequent sintering processing promotes the formation of stable nano Ti2Y2O7 oxide particles, which greatly increase the mechanical properties at elevated temperature and enhance irradiation resistance.

Engineering stress in thin films for the field of bistable MEMS

While stress-free and tensile films are well-suited for released in-plane MEMS designs, compressive films are needed for released out-of-plane MEMS structures such as buckled beams and diaphragms. This study presents a characterization of stress on a variety of sputtered and plasma-enhanced chemical vapour deposition (PECVD)-deposited films, including titanium tungsten, invar, silicon nitride and amorphous silicon, appropriate for the field of bistable MEMS. Techniques and strategies are presented (including varying substrate bias, pressure, temperature, and frequency multiplexing) for tuning internal stress across the spectrum from highly compressive (−2300 MPa) to highly tensile (1500 MPa). Conditions for obtaining stress-free films are also presented in this work. Under certain conditions during the PECVD deposition of amorphous silicon, interesting ‘micro-bubbles’ formed within the deposited films. Strategies to mitigate their formation are presented, resulting in a dramatic improvement in surface roughness quality from 667 nm root mean square (RMS) to 16 nm RMS. All final deposited films successfully passed the traditional ‘tape test’ for adhesion.

Impact of Tool Inserts in High Speed Machining of GFRP Composite Material

Composite materials are in-homogenous, anisotropic and cause high tool wear at high cutting speeds in machining. Industrial practices worldwide reveal a need to use high speed machining to achieve the desired material removal rate, surface finish and to reduce cost cutting. In this research work, impact of turning glass fibre reinforced polymer tube with two contrasting turning tool inserts such as titanium aluminium nitride and tungsten carbide have been analysed. The turning was conducted at low to high cutting conditions up to spindle speeds of 2000 rpm and feed rate of 0.446mm/rev. The cutting force, feed force were acquired with a strain gauge based dynamometer, the chip cross section was observed using scanning electron microscopy and the temperature was sensed with a infra red thermo sensor. The advanced titanium aluminium nitride insert shows better machining characteristics across cutting speeds.

Study on the performance of Tungsten–Titanium alloy film as a diffusion barrier for iron in a flexible CIGS solar cell

A Tungsten–Titanium (W–Ti) diffusion barrier was prepared on an iron (Fe) substrate by means of magnetron sputtering with subsequent annealing at different temperatures. Rutherford Backscattering Spectrometry (RBS) was used to analyze the Fe distribution in the W–Ti layer. The diffusion constant D0=3.4×10−16m2/s and the activation energy Q=43kJ/mol of the Fe diffusing in the W–Ti layer were subsequently calculated based on Fick’s Second Law. The results demonstrated that a 291nm-thick W–Ti barrier layer can be used to block Fe from diffusing into a CIGS solar cell for 20years at a work temperature of 308K (35°C).

Preparation and Photoelectrochemical Properties of Multilayered WS2 Coated Titanium Dioxide Nanocomposites

In this paper, nanocomposite titanium dioxide and tungsten sulfide (TiO2-WS2) was prepared through high energy ball milling. The images of scanning electron microscopy (SEM) show that particle size of the as-prepared nanocomposites is approximately ~300 nm. The analysis of X-ray diffraction (XRD) indicates formation of a few layers WS2 anchored on TiO2 nanoparticle surface, which present enhancement (> 90%) of visible light absorption after 32 hours ball milling. The photocurrent of the nanocomposite TiO2-WS2 correspondently increases about 10% under UV illumination.

Effect of W–Ti target composition on the surface chemistry and electronic structure of WO3–TiO2 films made by reactive sputtering

Tungsten–titanium (W–Ti) mixed oxide thin films were fabricated using reactive sputtering of W–Ti alloy targets with Ti content ranging from 0 to 30wt%. The effect of target composition on film structure, surface/interface chemistry and chemical valence state of the W and Ti cations was investigated in detail. All films were amorphous in nature as confirmed by X-ray diffraction analyses. For growth times of 1h, the thicknesses of the W–Ti–O films decreased significantly from 150 to 35nm with increasing Ti content in the target, confirming that the oxide film growth behavior is dependent on the sputter-target composition. The chemistry and composition of the films probed using X-ray photoelectron spectroscopy (XPS) confirms the existence of W and Ti in their highest oxidation states of 6+ and 4+, respectively. Quantification of binding energy shifts for W and Ti core-level transitions confirms the formation of WO3–TiO2 composite oxide films. Depth profiles confirm and validate film uniformity, as well as film thickness differences and variable oxidation behavior of W and Ti in the films.

Application of Inorganic Nanopowders in Welding, Surfacing and Spraying (Review)

The paper reviews research works on nanoincorporated consumables for welding, surfacing and spraying. Use of metal and compound nanoparticles is considered such as tungsten carbide, tungsten-cobalt carbide, chromium carbide, titanium carbonitride, aluminum oxide and others. It has been proved that inoculation of nanopowders results in modification of metal structure and improves service performance of weld joints.

Ultra-high purity tungsten and its applications

High purity (>99.999wt.%, 5N) or ultra-high purity (>99.9999wt.%, 6N) tungsten (W) electrodes are vital to the performance and lifetime of high intensity discharge (HID) lamps. On the other hand, alloys based on high purity (>99.99wt.% or 99.995wt.%, 4N or 4N5) W are used as sputtering targets to deposit the films in semiconductor devices. In this study, a highly efficient and cost-saving method for mass producing 6N W powder has been developed. The 5N and 6N W rods and wires for the electrodes of HID lamps have been manufactured by using this powder. In addition, vacuum hot pressing has been employed to prepare 4N5 tungsten–titanium (W–Ti) and 4N tungsten–silicon (W–Si) sputtering targets successfully. The impurities and microstructures of the developed high purity W products have been investigated and are suitable for lighting, semiconductor and photovoltaic applications.

Activation of Platinum-Based Centers through Modification with Metal Oxo Species toward Electrocatalytic Oxidation of Dimethyl Ether and Methanol

We have considered nanonstructured metal oxides as promoters for platinum, palladium or bimetallic platinum-ruthenium nanoparticles to fabricate electrocatalytic systems capable of efficient oxidation of dimethyl ether, a potentially new fuel of importance to low temperature fuel cells. The research has been performed in comparison to methanol. We explore the fact that certain inorganic oxides (e.g. WO3, TiO2, ZrO2 and CeO2) and polyoxometallates of molybdenum or tungsten tend to influence supported metal centers in ways other than simple dispersion over electrode area. Among useful characteristics of metal oxides and related systems are the following: they can generate –OH groups at low potentials that induce oxidation of passivating CO adsorbates (e.g. on Pt); they can potentially break C-H bonds (e.g. by hydrogen tungsten oxide bronzes); and they can possibly weaken C-O bonds during dimethyl ether oxidation (e.g. through changes of the electronic properties of Pt or Pd as additional component). Also nanostructured gold in combination with platinum has been demonstrated to enhance the overall electrocatalytic performance during oxidation of such small organic molecules as methanol and dimethyl ether. We pursue a concept of utilization of functionalized titanium dioxide, tungsten oxide and/or zirconium oxide matrices (by admixing them with polyoxometallate-modified gold nanoparticles) for supporting and activating noble metal nanoparticles (Pt, Pt-Ru, Pd, Pt-Pd) toward electrooxidation of dimethyl ether in comaprison to methanol. Remarkable increases of the respective electrocatalytic currents measured under voltammetric and chronoamperometric conditions have been observed. The most likely explanation takes into account improvement of overall conductivity (due to the presence of nanostructured gold) at the electrocatalytic interface (formed by metal oxide support), as well as and possibility of specific Pt-metal oxide or Pt-Au electronic interactions and existence of active hydroxyl groups on transition metal oxo species.in the vicinity of catalytic Pt sites. Further, the capping layers of Keggin-type phosphomolybdates, which are known to undergo fast stepwise multi-electron redox processes as well as to activate Pt-based electrocatalysts, may also contribute to the overall enhancement effect.

Tungsten laminates made of ultrafine-grained (UFG) tungsten foil — Ageing of tungsten–titanium (W–Ti) laminates

Through the synthesis of a tungsten laminate made of ultrafine-grained (UFG) tungsten foils, a UFG bulk material can be made that retains the ductility and toughness of the tungsten foils. Considering tungsten laminates as a structural material the ageing behaviour is of utmost importance.In this paper we analyse and discuss the ageing behaviour of tungsten laminates produced by diffusion bonding using a titanium (Ti) interlayer. The evolution of the mechanical properties (Charpy impact, hardness) and the evolution of the microstructure during annealing at 1000°C for 10h, 100h, and 1000h in vacuum are studied.The calculated Ti–W phase diagram, as well as the calculated interdiffusion coefficients and interdiffusion profiles, significantly relate to the understanding of the evolution of the W–Ti interface. Comparison of Auger electron spectroscopy (AES) and scanning electron microscope (SEM) analyses with the simulated diffusion data provides an in-depth understanding of the diffusion mechanisms and the evolution of the microstructure.The elucidation of the diffusion mechanisms of W–Ti laminates will advance several research fields such as the production of UFG bulk material and the synthesis of advanced fracture toughness test samples.

Workability Behavior of Powder Metallurgy Carbide Reinforced Aluminum Composites During Hot Forging

Experimental study was conducted to assess the consequence of titanium carbide (TiC), molybdenum carbide (Mo2C), iron carbide (Fe3C), and tungsten carbide (WC) reinforcements on the composite aluminum compacts. The hot deformation of the carbide reinforce aluminum compacts, Al-2TiC, Al-2WC, Al-2Fe3C, and Al-2Mo2C, with aspect ratios of 0.4 and 0.6, was carried out and the workability behaviors of the same were determined. The effect of carbide reinforcement and preform geometry on the relative density, stress ratio, σθ/σeff, and formability ratio was studied.

Study of alternative back contacts for thin film Cu2ZnSnSe4-based solar cells

Cu2ZnSnSe4 thin film solar cells are usually fabricated on a soda lime glass substrate with a molybdenum (Mo) back contact. It is suspected that degradation in electrical performance occurs due to the formation of a barrier between the absorber and Mo back contact. To overcome such degradation, Titanium Nitride (TiN), Titanium Tungsten (TiW), Chromium (Cr), Titanium (Ti) and Aluminum (Al) deposited on Mo-coated glass substrates are investigated as alternative back contact materials. Physical and electrical characterization as well as photoluminescence measurements are performed. Compositional analysis of the absorber layer on the metallized substrates identifies Mo, TiN and TiW as being the most inert during the formation of Cu2ZnSnSe4. On the other hand, Ti and Cr reacted with Se during selenization, thereby affecting the growth of the absorber, leading to low conversion efficiency. For Al, the absorber layer was etched after the standard potassium cyanide etch, hence, cannot be used as a back contact. The best device efficiencies obtained are 8.8% on TiN, 7.5% on Mo and 5.9% on TiW, respectively. The TiN back contact provides the lowest barrier value of about 15 meV which could be considered as a good ohmic contact.

Workability studies of sintered aluminium composites during hot deformation

Experimental investigation has been carried out to evaluate the effect of titanium carbide (TiC), molybdenum carbide (Mo2C), iron carbide (Fe3C) and tungsten carbide (WC) addition on the composite aluminium preforms. The hot upsetting of the composite aluminium preforms with various carbide contents, namely, Al-4% TiC, Al-4% WC, Al-4% Fe3C and Al-4% Mo2C, and different aspect ratios, namely, 0.4 and 0.6, was carried out and the workability behaviour of the same was determined. The influence of carbide addition in the aluminium composite and initial preform geometry on the relative density ( R), stress ratio parameters, [Formula: see text], [Formula: see text] and [Formula: see text], and formability stress index was studied.

Solid State Electrochromic Devices of Plasma Modified WO3Hybrids

Electrochromic (EC) properties of tungsten trioxide (WO3) was improved with preparing hybrids of tungsten trioxide–titanium dioxide (WO3–TiO2) and tungsten trioxide–poly(3,4-ethylenedioxythiophene) (WO3–PEDOT) by a rotating capacitively coupled radio frequency (rf 13.56 MHz) plasma reactor. Energy-dispersive X-ray spectroscopy mapping results indicated that TiO2 and PEDOT were coated homogeneously onto the surface of the WO3 powders. Thin films of hybrid powders have been prepared by the physical vapor deposition method of the electron beam evaporation technique. Redox potentials, optical contrast at 700 nm, and durability during 2000 cycles of EC devices were investigated, comparatively. Hybrids of WO3 indicated excellent coloration efficiency (cm2 C–1) and switching speed values compared with untreated WO3. The coloration efficiency values were found to be 85.88 and 41.61 cm2 C–1 of WO3–TiO2 and WO3–PEDOT, respectively. The switching speed of WO3 (13.3 s, from bleached state to colored state) increased ...

Chromium–tungsten–titanium mixed oxides solid catalyst for fatty acid methyl ester synthesis from palm fatty acid distillate

Chromium–tungsten–titanium mixed oxides solid catalysts were prepared and evaluated in the esterification of palm fatty acid distillate (PFAD) to produce fatty acid methyl ester (FAME). Esterification was conducted in a batch reactor at 110–200°C temperature ranges. The catalysts were characterized by several techniques such as BET, TEM, FTIR, TGA, XRD, EDX and SEM. The treatment conditions during catalyst preparation, effect of reaction parameters, leaching of the active species and the recycled use of the catalyst were investigated. The catalyst with formula CrWTiO2 was found to be the most active with maximum FAME content of 83% obtained at best reaction conditions of 170°C for 3h, 2:1 (methanol to oil molar ratio) and 2wt.% catalyst dosage. The catalyst can be recycled for 4 times. The results revealed CrWTiO2 good potentials for use in esterification of high acid value oil.

Lysozyme-mediated biomineralization of titanium-tungsten oxide hybrid nanoparticles with high photocatalytic activity.

Titanium-tungsten oxide composites with greatly enhanced photocatalytic activity were synthesized by lysozyme-mediated biomineralization. It was shown for the first time that simple control of the onset of biomineralization could enable fine tuning of the composition and crystallinity of the composites to determine their photocatalytic performance.