Synthesis Of Ti Research Articles

Synthesis of Ti1‐xWx Solid Solution MAX Phases and Derived MXenes for Sodium‐Ion Battery Anodes

AbstractA distinguishing feature of MAX phases and their MXene derivatives is their remarkable chemical diversity. This diversity, coupled with the 2D nature of MXenes, positions them as outstanding candidates for a wide range of electrochemical applications. Chemical disorder introduced by a solid solution can improve electrochemical behavior. Up to now, adding considerable amount of tungsten (W) in MAX phase and MXenes solid solutions, which can enhance electrochemical performance, proved challenging. In this study, the synthesis of M site Ti1‐xWx solid solution MAX phases are reported. The 211‐type (Ti1‐xWx)2AlC exhibits a disordered solid solution, whereas the 312‐type (Ti1‐xWx)3AlC2 displays a near‐ordered structure, resembling o‐MAX, with W atoms preferentially occupying the outer planes. Solid‐solution MXenes, Ti2.4W0.6C2Tz, and Ti1.6W0.4CTz, are synthesized via selective etching of high‐purity MAX powder precursors containing 20% W. These MXenes are evaluated as sodium‐ion battery anodes, with Ti1.6W0.4CTz showing exceptional capacity, outperforming existing multilayer MXene chemistries. This work not only demonstrates the successful integration of W in meaningful quantities into a double transition metal solid solution MAX phase, but also paves the way for the development of cost‐effective MXenes containing W. Such advancements significantly widen their application spectrum by fine‐tuning their physical, electronic, mechanical, electrochemical, and catalytic properties.

Compacting of Material by Combining Spark Plasma Sintering and Self-Propagating High-Temperature Synthesis in Ti–Al–C System

Compacting of Material by Combining Spark Plasma Sintering and Self-Propagating High-Temperature Synthesis in Ti–Al–C System

Novel synthesis of Ti–Fe2O3/MIL-53(Fe) via the in situ process for efficient photoelectrochemical water oxidation

The slow kinetics of water oxidation has become a challenge for photoelectrochemical hydrogen production. Here, a novel organic-inorganic integrated photoanode system was constructed by using MIL-53(Fe) formed during the in-situ etching process as a cocatalyst to modify Ti–Fe2O3. The photocurrent density of Ti–Fe2O3/MIL-53(Fe) reaches 2.5 mA/cm2, 10 times that of bare Ti–Fe2O3 at 1.23 V vs. RHE, and the water oxidation photocurrent onset potential shifts 105 mV negatively. Ti–Fe2O3/MIL-53(Fe) reaches 52% at 390 nm for IPCE. The excellent photoelectrochemical performance is due to iron oxide clusters boost charge separation and transfer, in-situ etching exposes more reactive sites, and the tight connection reduces interfacial resistance, which greatly accelerates the surface kinetics of Ti–Fe2O3. The in-depth understanding is provided for in-situ modification of photoanodes by metal organic frameworks in this work.

Synthesis of Ti3SiC2 MAX phase powder through molten salt method

AbstractTitanium silicon carbide (Ti3SiC2) MAX phase powder was synthesized from elemental reactants using the molten salt synthesis (MSS) method. Optimum experimental parameters were also investigated to determine the purity and synthesis pathway of the Ti3SiC2 MAX phase. The results showed that Ti3SiC2 was not synthesized using carbon black as the carbon source in the starting materials because of the high quantity of TiC formed along with the TiSi2 silicide phase. However, Ti3SiC2 was successfully synthesized in a relatively high purity (93%) at 1200°C for 2 h using graphite as the source of carbon because of the formation of TiC and Ti5Si3 intermediate phases. The Ti5Si3 silicide phase was found to play a crucial role in the formation of the Ti3SiC2 MAX phase using the MSS method. Moreover, applying a pressure of 150 MPa to the prepared samples and using the eutectic mixture of NaCl–KCl (molar ratio: 1:1) instead of NaCl also resulted in the higher formation of the Ti3SiC2 MAX phase. The formation mechanism of Ti3SiC2 was determined to be the reaction among Ti5Si3, TiC, and residual carbon through the template‐growth and dissolution–precipitation mechanisms that occurred at different stages of the synthesis process.

Self-Propagiating High-Temperature Synthesis in Ti–Al–Mn System

Self-Propagiating High-Temperature Synthesis in Ti–Al–Mn System

Electrochemical performance of Ti3C2Tx MXenes obtained via ultrasound assisted LiF-HCl method

In the present work, ultrasound was introduced throughout the synthesis of Ti 3 C 2 Tx MXene, the synthesis efficiency and energy storage performance of the MXenes were significantly improved under the aid of ultrasound. It was verified that intercalation of Li + between the adjacent layers of Ti 3 C 2 Tx MXene was greatly promoted by the ultrasound. Under the impact of ultrasound, the 8 h sonicated etched showed a specific capacitance of 270.5 F/g, which is a 16-fold enhancement compared with the sample without the aid of ultrasound. Monolayered samples with and without sonication treatment were synthesized, and the sample prepared in presence of ultrasound showed a specific capacitance of 420.66 F/g. The specific capacitance retention of the 8 h ultrasonically etched multiple layered samples after 10,000 cycles at 5 A/g was 95.52%, 4.27% higher than the corresponding value of the monolayered sample. • The ultrasonic was introduced throughout the synthesis process of Ti3C2Tx MXene • The timescale of etching was shortened to 8 hours in presence of ultrasound • The ultrasonically etched sample exhibits superior electrochemical performance • The contribution of capacitive behavior for energy storage was investigated

Synthesis of Ti–Al Bimodal Powder for High Flowability Feedstock by Electrical Explosion of Wires

In this research, Ti–Al bimodal powders were produced by simultaneous electrical explosion of titanium and aluminum wires. The resulting powders were used to prepare powder–polymer feedstocks. Material characterization involving X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and melt flow index (MFI) determination were carried out to characterize bimodal powders obtained and evaluate the influence of the powder composition on the feedstock flowability. The bimodal distribution of particles in powders has been found to be achieved at a current density of 1.2 × 107 A/cm2 (the rate of energy input is 56.5 J/μs). An increase in the current density to 1.6 × 107 A/cm2 leads to a decrease in the content of micron particles and turning into a monomodal particle size distribution. The use of bimodal powders for powder–polymer feedstocks allows to achieve higher MFI values compared with monomodal powders. In addition, the use of electroexplosive synthesis of bimodal powders makes it possible to achieve a homogeneous distribution of micro- and nanoparticles in the feedstock.

Влияние электронно-пучковых обработок на уровень остаточных напряжений в системе “поверхностный Ti – Ni – Ta – Si сплав/TiNi-подложка”

TiNi shape memory alloys exhibiting martensitic transformations are attractive materials in the industry of micromechanical systems. The key issue responsible for degradation of functional properties of TiNi during operation is residual stresses arising from the sample processing and surface treatments. In this work, we investigated TiNi substrates modified after synthesis of Ti – Ni – Ta – Si surface alloys (SA) by additive thin film electron-beam (ATF-EB) method. The effect of electron-beam treatments of the system “[Ti – Ni – Ta – Si]SA/TiNi substrate” at the energy density (ES = 1.7 J/cm2) and pulse number n = 10 on the elastic-stress state of the B2 phase in TiNi substrate has been studied. Detailed analysis by X-ray diffraction (XRD) and transmission electron microscopy (TEM) has shown the formation of two isostructured B2 phases with different lattice parameters, chemical composition, and microstructure. It has been found that changes in the B2 lattice parameters are closely related to the variation of the chemical composition and residual elastic stresses of the first kind. The study of residual stresses in the samples reveals that compression stresses in the direction perpendicular to the irradiated surface reach a value of –350 MPa. After additional electron-beam treatment, the compression stress value decreases to –270 MPa.

Synthesis of Ti4+ doped Ca-BiFO3 for the enhanced photodegradation of moxifloxacin

In recent years, the continuously increasing demand for wastewater treatment has increased research on perovskite-based materials with narrow band gaps.

Self-Propagating High-Temperature Synthesis of Ti<sub>3</sub>SiC<sub>2</sub> and Ti<sub>3</sub>AlC<sub>2</sub> Single-phase Max Phases in Mechanically Activated Mixtures of Initial Reactants

Self-Propagating High-Temperature Synthesis of Ti<sub>3</sub>SiC<sub>2</sub> and Ti<sub>3</sub>AlC<sub>2</sub> Single-phase Max Phases in Mechanically Activated Mixtures of Initial Reactants

Synthesis of Ti(C, N, O) ceramic from rutile at low temperature by CH4-H2-N2 gas mixture

Titanium carbides, oxides, nitrides, and carbonitrides possess many special and excellent properties. But the high production cost caused by the traditional carbothermic reduction process severely limits the wide applications. In this study, a novel synthesis process has been proposed by reducing and carbonitriding TiO2 with a CH4-H2-N2 gas mixture at low temperatures. The synthesis of Ti(C, N, O), reaction mechanism, and the composition of the product have been investigated. Thermodynamic analysis indicated that TiO2 could be ultimately reduced and carbonitrided to Ti(C, N, O) by CH4-H2-N2 gas mixture. Based on the predictions of thermodynamics, the effects of reduction time, temperature, and gas composition have been studied experimentally. The obtained results indicated that increasing reduction temperature and introduction of N2 are beneficial to the synthesis of Ti(C, N, O). Finally, the optimum reaction conditions have been obtained. The density functional theory (DFT) results further demonstrated the reaction mechanism. This work provides a new approach to prepare metallic carbonitrides from their oxides.

Reaction synthesis of gradient coatings by annealing of three-layer Ti–Ni–Ti nanolaminate magnetron sputtered on the TiNi substrate

In this work, Ti-Ni-Ti nanolaminate was deposited on a TiNi substrate by magnetron sputtering. Subsequent synthesis in Ar at temperatures of 500, 700 and 900 °C was carried out. To investigate the effect of the reaction synthesis temperature for obtaining a dense thin intermetallic biofunctional coating, a comparative analysis of the morphology, structure, phase composition, mechanical properties and wettability of the coatings was carried out. It was found that crystallization processes have a different impact on the amorphous Ti and Ni layers depending on temperature. In all cases, multilayer gradient crystalline coatings were formed that bound to the substrate by the diffusion zone. The reaction synthesis temperatures of 500 and 700 °C are insufficient for reaction completion and complete transformation; therefore, the obtained thin loose layers are unstable under stresses caused by the substrate. Reaction synthesis in Ti – Ni – Ti nanolaminate at 900 °С formed a dense two-layer gradient coating 2 µm thick, which reliably protects the matrix from further diffusion of interstitial impurities and segregation of Ni atoms onto the surface. An analysis of the nano-indentation deformation diagrams showed that the coatings do not prevent the viscoelastic deformation of the TiNi substrate.

Preparation of TiO2 Nanoparticle Aggregates and Capsules by the ‘Two-Emulsion Method’

TiO2-based materials are of great practical interest in several technological areas. Both the size and the morphology of the TiO2 particles are of critical importance for their applications. The current study explores the effect of several factors on the outcome of the TiO2 particle synthesis via the so-called ‘two-emulsion method’. In this technique, two water-in-oil emulsions—each of them containing different reactant in the dispersed water drops—are mixed under well controlled conditions. Upon such mixing, partial coalescence of the water drops from the two emulsions leads to mixing of the drop content, with chemical reaction occurring within the drops, and to synthesis of Ti(OH)4 particles. Afterwards, the latter are transformed by emulsion heating into TiO2 particles and aggregates of predominantly anatase structure. Our results show that—depending on the precursor and surfactant concentrations, oil viscosity, emulsification time, and mixing speed—the obtained nanoparticles could aggregate either on the drop surface, forming capsules with a very smooth surface, or inside the water droplets, thus leading to hierarchically structured aggregates of micrometer size. The spherical smooth capsules are constructed of very small monodisperse TiO2 nanoparticles with size below 5 nm. The hierarchical bulk aggregates, on the other hand, are formed from bigger primary particles of sub-micrometer size. The obtained results show that one can obtain various TiO2 structures by controlling the conditions during the emulsion preparation and mixing

Synthesis of Ti(OH)OF ⋅ 0.66 H2 O in Imidazolium-based Ionic Liquids.

The influence of the cation of imidazolium‐derived ionic liquids (ILs) on a low‐temperature solution‐based synthesis of hexagonal tungsten bronze (HTB) type Ti(OH)OF ⋅ 0.66 H2O and bronze‐type TiO2(B) is investigated. The IL (Cxmim BF4) acts as solvent and also as reaction partner with respect to the decomposition of [BF4]−, releasing F−. In the present study, the chain length of the alkyl chain side groups attached to the imidazolium ring was varied (C2mim BF4 to C10mim BF4), and the obtained solids were analyzed by Powder X‐Ray diffraction (PXRD) followed by Rietveld refinement. As a main finding these analyses indicate a transformation of Ti(OH)OF ⋅ 0.66 H2O into TiO2(B), and upon prolonged reaction time finally also into anatase TiO2. Rietveld analysis suggests that when using ILs with longer alkyl chains, the conversion of Ti(OH)OF ⋅ 0.66 H2O is slower compared to syntheses performed with smaller alkyl chains. Hence, Ti(OH)OF ⋅ 0.66 H2O appears to be metastable and is stabilized by long‐chain ILs serving as surfactant attached to the crystallites’ surface. In this view, the ILs shield the nanoparticles and thus slow down the conversion into the more stable compounds. This confirms previous findings that ILs act as both, solvent and reaction medium in this reaction, thus enabling the synthesis of peculiar Ti‐oxides.

Chemically driven synthesis of Ti3+ self‐doped Li4Ti5O12 spinel in molten salt

AbstractSurface doping of Li4Ti5O12 (LTO) with Ti3+ ions is an effective way to enhance its electrochemical properties for lithium ion batteries (LIBs). Herein, a molten salt approach was reported to synthesize Ti3+ self‐doped LTO powder. The reaction mechanism and the role of molten salt for the synthesis have been systemically discussed. Finally, electrochemical performance of the LTO powder was preliminarily evaluated as anode material of LIBs. The molten salt accelerated the mass transportation for the formation of LTO by transferring a solid diffusion to the diffusion of ions in a liquid media. Self‐doping of Ti3+ ions on the surface of LTO particles was achieved by controlling equilibriums of chemical reactions in the reactor. Electrochemical performance of the LTO powders was effectively promoted by doping Ti3+ ions on the surface. The discharge capacity of the Ti3+ self‐doped LTO powder prepared at 850°C was 171 mAhg−1, and the capacity dacayed 9.9% after 200 cycles at a rate of 0.5 C.

Effects of magnesium on initial temperature and mechanical activation on combustion synthesis in Ti–Al–Mg system

Nowadays the investigation of new lightweight alloys based on titanium aluminides is of great interest. Various low-density dispersion-strengthening additives are used for their synthesis. In this work Ti–Al–Mg lightweight alloy was synthesized using the methods of layer-by-layer combustion and thermal explosion. Relative sample elongation, combustion velocity, and maximum combustion temperature of Ti–Al–Mg system depend on the initial temperature and Mg presence. Phase analysis of the synthesized products with or without mechanical activation of the initial mixture reveals the existence of γ-TiAl, α2-TiAl3, Ti3Al, MgO phases, and γ-TiAl, α2-TiAl3, TiAl2, MgO, and α−Ti phases, respectively. The products synthesized by the thermal explosion mode from mechanically activated mixtures, preliminarily preheated to a temperature above 250 °C, contain the ternary Al18Ti2Mg3 phase. Mg shifts the reaction of Ti and Al to lower temperatures.

Synthesis of Ti(C, O, N) from ilmenite at low temperature by a novel reducing and carbonitriding approach

The clean and effective utilization of titanium-bearing minerals has challenged the titanium industry all over the world. In order to realize the high-efficiency, clean, and high value-added comprehensive utilization of ilmenite concentrate, a novel process has been proposed in this study by reducing and carbonitriding ilmenite with the CH4-N2-H2 gas mixture at low temperature. Carbonitride performance and mechanism have been investigated experimentally and theoretically. The obtained results showed that the reaction process could be divided into three stages: formation of metallic iron, reduction of titanium oxide to titanium suboxides, and formation of Ti(C, O, N). The metallic iron congregated at the first two stages, but dispersed once the Ti(C, O, N) formed. The effects of both reaction temperature and preoxidation treatment on the reaction have been studied as well. It was found that the increase of temperature was conducive to the formation of Ti(C,O), and the ilmenite could be reduced completely to Ti(C,O) at 1170°C for 8 hours. The preoxidation treatment could improve the kinetics of reduction. At 1170°C, the introduction of N2 could apparently increase the reduction rate, with the complete reduction time decreasing from 8 hours in CH4-H2 gas mixture to 3 hours in CH4-N2-H2 gas mixture. The proposed novel process has been assessed and it showed many potential advantages and feasibility.

Synthesis of Ti$_3$AlC$_2$ MAX-Phase with Different Content of B$_2$O$_3$ Additives

Synthesis of Ti$_3$AlC$_2$ MAX-Phase with Different Content of B$_2$O$_3$ Additives

Formation mechanism and controllable preparation of Ti(C,N) in Al–TiO2–Al2O3 composite at 1673 K in flowing N2

In this paper, the Ti(C,N)–Al2O3 refractory was successfully prepared at 1673 K in flowing N2 by using brown fused alumina, rutile and Al as the raw materials, phenolic resin as the binding agent. The formation mechanism of Ti(C,N) in the Al–TiO2–C matrix and resin-bonded Al–TiO2–Al2O3 refractory was investigated by the means of XRD, SEM and EDS, respectively. Results showed that the synthesis of Ti(C,N) in Al–TiO2–C matrix required (TiO2:C)mol>1, and this condition was achieved in the Al–TiO2–Al2O3 refractory by using phenolic resin as the carbon source. When the resin-bonded Al–TiO2–Al2O3 refractory was heat-treated under high temperature and nitrogen conditions, the stability of TiO2 in the refractory decreased and gradually transformed into Ti-containing nano particles (TiO, (Al, Ti)O2 and TiC), Al3Ti and (Al–Ti)melt. Then the TiC was further transformed into Ti(C,N) by the reaction TiC(s)+TiAl–Ti(l)+N2(g)→Ti(C,N)(s) after the refractory was transformed into an Al2O3–TiC-(Al–Ti)melt system at high temperatures.

Ti(dibenzoylmethane)₂(O-i-Pr)₂ 합성과 L-락티드 개환중합

Poly(L-lactide)(PLA) 중합용 신규 촉매를 개발하기 위하여 Ti(O-i-Pr)₄와 dibenzoylmethane(dbm)을 이용, Ti(dbm)₂(O-i-Pr)₂ 촉매를 합성하였고 PLA 중합특성을 확인하였다. Ti(dbm)₂(O-i-Pr)₂ 촉매 PLA 중합 특성은 L-락티드/촉매 몰비 및 중합시간을 변화시키며 관찰하였다. L-락티드/촉매 몰비가 증가함에 따라 전환율과 분자량이 증가하였다. Ti(dbm)₂(O-i-Pr)₂ 촉매는 촉매 내 페닐기가 존재하여 중합 반응 중 락티드 삽입을 방해하기 때문에 촉매 활성이 낮은 것으로 판단된다. Benzyl alcohol을 개시제로 사용하여 중합한 결과 Ti(dbm)₂(O-i-Pr)₂ 촉매 전환율이 대폭 감소하였다. 얻어진 중합물은 DSC, GPC를 이용하여 녹는점과 분자량을 측정하였고 1H NMR로 PLA의 분자구조를 확인하였다.