Multilayer Ti Research Articles

Effects and modulation mechanism of crystal structure on residual stress of Cu films used for metallization

Deformation cracking and delamination arising from residual stress are the main challenges for metallization in large-scale integrated circuits. Herein, an ultra-low residual stress Cu film is prepared on amorphous SiO2 by mixed power magnetron sputtering. Compared to conventional Cu films, the residual stress in the film decreases by 1,434 times. The nano multi-layer structure produces lower stress and deformation as well as better reliability. The multi-layer Ti underlayer also reduces the residual stress and promotes the low-defect growth of Cu. The lower surface roughness, smaller dislocation density, predominant grain orientations of <111> and <001>, and more substructures are beneficial to the reduction of residual stress. In addition, interlayer stress cancellation can be achieved by changing the number of <111> grains. The research on grain growth at the interface of nano multi-layer films reveals an effective means to fabricate films with low residual stress for metallization in integrated circuits.

Qualitative Identification of the Spin‐to‐Orbital Conversion Mechanism Modulated by Rare‐Earth Nd, Gd, and Ho Metals via Terahertz Emission Measurements

AbstractIt is crucial to study the materials that could effectively facilitate the inter‐conversion between charge, spin, and orbital degrees of freedom. In this work, the conversion among these three types of degrees of freedom in Pt/CoFeB/rare‐earth (RE, represents Nd, Gd, and Ho)/Ti multilayers is manipulated. Through terahertz (THz) emission measurements, it is found that the spin current induced by a femtosecond laser is converted into an orbital current via the spin‐orbit coupling of the RE layer. Notably, the light RE (Nd) and heavy RE (Gd and Ho) induce the orbital current with opposite polarization directions, ultimately leading to a weakening or enhancement of the THz emission intensity, respectively. Moreover, the fast Fourier transform reveals that Gd exerts the most significant influence on increasing the whole THz spectrum within the Pt/CoFeB/RE/Ti structure. The findings of RE‐modulated spin‐to‐orbital conversion provide valuable insights into the fundamental transport mechanism of the orbital current.

Mechanism and growth kinetics of Al3Ti phase in fifteen-layered Ti Gr.1/A1050 clads produced with the explosive welding technique

This study was dedicated to the detailed characterization of the microstructural changes and the phase analysis of the interfaces formed in explosive welding of multilayered Ti Gr.1/A1050 clads. The significant effect of the detonation source localization on the microstructure of the welded materials interfaces after collision, and consequently on the diffusion processes induced by the elevated temperature was showed. Annealing process at 550 °C for series of time intervals of the Ti/Al clad allowed to determine the growth mechanism of the Al3Ti phase formed along particular interfaces. Moreover, the microstructure observations and calculations evidenced different growth mechanisms related to the localization of the Ti/Al interface in respect to the detonation source.

Combination of MSC Marc and SE-FIT to simulate the direct laser deposition of the multi-layer Ti–6Al–4V

Modeling the impact of a laser heat source on Ti6Al4V deposition is crucial for optimizing additive manufacturing, particularly in multi-layer contexts. This modeling provides insights into the material’s behavior during the Ti6Al4V manufacturing process. In this study, simulations using MSC Marc were conducted to model the impact of a laser heat source on the deposition of the multi-layer Ti–6Al–4V (abbreviated as Ti6Al4V) using the Ti–6Al–4V metal powder, followed by SE-FIT simulation to characterize their deposition morphology. MSC Marc was utilized to simulate the impact of a laser heat source on the Ti6Al4V, with a focus on identifying the melting area. Thermal conductivity was represented in the form of a chart as a function of temperature. Next, the morphology after deposition was defined using SE-FIT based on volume and boundaries. In the MSC Marc numerical model, a combined heat transfer coefficient of radiation and convection was applied to the convective coefficient. In the section depicting the multi-layered deposition morphology, a laser with 750[Formula: see text]W power was utilized at a speed of 3.3[Formula: see text]mm/s. After simulation, the resulting layer height and appearance were compared with the literature for a 25-layer composite. The practical implications of this research extend to the broader field of laser-induced heat deposition on Ti6Al4V deposition, which has applications beyond titanium alloys. The findings may contribute to advancements in the design and manufacturing of various metal components, impacting industries such as automotive, electronics and energy.

Preparation and tribologic properties of Ti and Zr nitride multilayer coatings

This paper focuses on synthesis and characterization of Zr/Ti and Ti/Zr nitride multilayer coatings by magnetron plasma sputtering to enhance the tribologic properties. The synthesis of nitrides was achieved by non-reactive deposition using Ti or Zr nitride targets or by reactive deposition using Ti or Zr targets in the presence of nitrogen. The formation of nitride layers was highlighted by XRD, EDX and XPS investigations, while the tribologic properties were made with HFRR equipment. The tribological study showed that the coefficient of friction and wear scar diameter decrease in multilayer films with zirconium nitride as the upper layer.

Fabrication and characterization of a novel multilayer heterojunction Si3N4-PbO2 nanocomposite electrode and its application on electrocatalysis degradation of sulfathiazole

To lengthen the lifetime and extend the potential commercial applications of lead dioxide electrode, herein, a novel multilayer heterojunction Ti/ SnO2-Sb2O3/ graphene oxide/ carbon nanotube/ Si3N4-PbO2 electrode (Si3N4-PbO2 electrode) was fabricated by co-electrodeposition process that doping Si3N4 nanoparticles in eletroplating solution. Various spectroscopic and microscopic techniques, including scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were employed to characterize the surface of the fabricated electrode. The EDS analysis confirmed the successful attachment of 5.49 %wt Si and 2.46 %wt N elements from Si3N4 nanoparticles onto the PbO2 surface, while the XRD results indicated a shift in the preferred orientation of PbO2 grains from β(110) to β(101). The water adsorption energy and ·OH desorption energy in the electrocatalysis process were determined to be 0.71 eV and 0.241 eV through theoretical calculating. Subsequently, the Si3N4-PbO2 electrode was employed as an anode for the electrocatalytic degradation of sulfathiazole-simulated wastewater and real sulfonamides wastewater. Under optimized conditions determined via response surface methodology (RSM), the COD degradation efficiency reached 69.37 % for sulfathiazole and 62.35 % for real sulfonamides wastewater. The final COD concentration of the real sulfonamides wastewater was reduced to 77.05 mg/L, under the national urban sewage discharge standard. Finally, the degradation mechanism and pathway of sulfathiazole has been arranged based on the electron spin resonance (ESR), cyclic voltammetry (CV), while the intermediates were detected by Gas Chromatography-Mass Spectrometer (GC-MS) and the reactive sites of sulfathiazole were predicted by using Fukui function.

Multi-layered Ti–Si solar absorber design based on tungsten material for solar thermal energy conversion

We present a solar absorber with a higher absorptance with Multi-layers Titanium (Ti)- Silicon (Si) based on Tungsten material. Tungsten is used as a ground layer, and Si and Ti are stacked in multilayered positions above that. The absorptance can be calculated in six peak wavelengths between the overall wavelength spectrum for 0.2–3 μm. The overall solar absorptance is 93.87% with a bandwidth of 2300 nm, above 95% with a bandwidth of 1000 nm, and above 97% at 800 nm. The situation of solar absorptance is improved by adding multi-layered structure and this is also exhibited with the respective absorptance (A), reflectance (R), and transmittance (T) step by step. Moreover, all absorptance are distributed in one figure, and AM 1.5 figure is also included. The solar absorption variation can also be checked by changing the parameters of ground layer width and thickness, and Ti and Si resonator thickness. The solar absorption situation can be expressed in TE and TM modes by changing the degree from 0 to 50. The electric field intensity and comparison between other published works are also presented. Thus, the proposed solar absorber can be possible to use in many ways with a higher absorptance. It can be provided from individual home facilities to production in large industries.

Nonlocal orbital torques in magnetic multilayers

We investigate current-induced torques in Ni/Ti/Fe/Ti multilayers. In the multilayers, we find that the damping-like torque acting on the Ni magnetization increases with the thickness of the bottom Ti layer, despite the negligible spin Hall conductivity of Ti and the presence of the Fe interlayer that effectively absorbs the transverse spins. The nonlocal nature of the observed torque is consistent with the orbital torque arising from the orbital Hall effect in the Ti layer and orbital transport through the Fe layer. This observation highlights the unique features of the orbital currents, offering enhanced flexibility in the design of spintronic devices.

Growth behavior of CVD Ti(C,N,O) coating on cemented carbide controlled by CO and the mechanism

In α-Al2O3-based chemical vapor deposition (CVD) coatings, Ti(C,N)- or Ti(C,N,O)-based layer exerts a significant influence on the crystal growth of α-Al2O3 and the performance of the coated cemented carbide cutting tools. To explore the reinforcement measures and the related mechanism of α-Al2O3-based coating, the effect of CO volume fraction from 0 to 8% on the growth behavior of Ti(C,N,O) on cemented carbide is systematically investigated. Both multilayer and monolayer Ti(C,N,O) coatings and Ti(C,O) intermediate were deposited at 830 °C in an industrial-scaled hot-wall CVD reactor. Experimental results show that CO reacts with TiCl4 in the H2 atmosphere, resulting in the formation of nanocrystalline Ti(C0.5,O0.5) with a slow growth rate. Thermodynamic calculation reveals that with the increase of CO fraction, the equilibrium partial pressure of HCN increases, which is a vital gas-phase for the formation of Ti(C,N,O). As a result, grain refinement and increase in the growth rate and oxygen content of Ti(C,N,O) coating are achieved by increasing the CO fraction and hence the amount of Ti(C0.5,O0.5) with strong reactivity. The growth mechanism of Ti(C,N,O) concerning the codeposition and their in situ reaction of Ti(C,N) and Ti(C,O) is proposed, and the related phenomena of preferential growth transformation and Cl residue in Ti(C,N,O) coating are discussed.

Structural, mechanical properties and corrosion performance of multilayer Ti doped-DLC/Ti films deposited on low-carbon steel

In this work, the successful preparation of the multilayer Titanium doped diamond-like carbon/Ti (Ti-DLC/Ti) films deposited on low-carbon steel (CS) using hybrid magnetron sputtering (MS) and plasma-enhanced chemical vapor deposition methods has been reported. The Ti and Ti-DLC films were alternately deposited on the CS substrate of up to 4 stacks with an average deposition rate of 16.4±1.7 nm/min and 15.1±1.5 nm/min, respectively, yielding a total thickness of up to 1703 nm. Raman spectroscopic analysis revealed a gradual increase in the I D/I G ratio with an increase in Ti layer numbers. Both XPS and NEXAFS results indicate an increase in the C-sp 2 content by increasing the number of Ti layer, which may influence on the hardness reduction. The adhesive properties were found to be improved by adding the number of Ti interlayers between the CS substrate. Moreover, the thicker multilayer films exhibit progressive homogeneity resulting in better corrosion resistance.

NaCl-induced hot-corrosion behavior of TiAlN single-layer and TiAlN/Ti multilayer coatings at 500 °C

The microstructure and corrosion behavior of the TiAlN and the TiAlN/Ti coatings were studied under the synergistic effects of salt spray and high temperature at 500 °C. The results showed that the salt spray test accelerated the hot corrosion process of the coatings. The columnar grain boundaries of TiAlN coatings provide a preferred position for internal corrosion, where the corrosion product was mainly composed of TiO 2 . The TiAlN/Ti multilayer interface and Ti interlayer have double effects on the hot corrosion resistance of the coating. The Ti metal layer restrained the corrosion zone propagation to TiAlN layer and also aggravated the local corrosion inside the coating. The corrosion mechanisms of TiAlN and TiAlN/Ti coatings were discussed in detail. • The hot corrosion behaviors of TiAlN single-layer and TiAlN/Ti multilayer coatings were investigated. • During the hot corrosion process, the Ti and Al elements were consumed greatly, and no complete and protective oxide layer was formed. • The columnar grain boundaries of TiAlN coating provide favorable position for internal corrosion. • Ti metal layer was preferentially corroded in TiAlN/Ti coating. It provides a reference for the development of new nitride coatings.

The giant orbital Hall effect in Cr/Au/Co/Ti multilayers

The spin–orbit torques originating from the spin Hall effect of heavy metals are of vital importance for applications in spintronics due to its low consumption of energy. Theoretical calculations have predicted that 3d and 4d light metals can produce a similar amount of torques to heavy metals via the strong orbital Hall effect (OHE). However, few experiments have been conducted since it is technically challenging to directly detect the orbital current from the OHE. Here, we report an effective approach to demonstrate the strong orbital torques in the light metal Cr with the aid of a conversion process from the orbital current to the spin current by introducing an Au interfacial layer in the Cr/ferromagnet structures. A rather large orbital torque efficiency and an increase with the increasing thickness of the Cr-layer are attained in the perpendicularly magnetized Cr/Au/Co/Ti multilayers. Moreover, an energy efficient magnetization switching and the domain wall motion in Cr/Au/Co/Ti multilayers induced by the OHE have also been observed. Our findings confirm the existence of the orbital Hall torques in Cr and provide an effective way to investigate the OHE.

Ultraviolet-assisted construction of low-Pt-loaded MXene catalysts for high-performance Li−O2 batteries

Achieving high electrocatalytic activity with low amount of noble metals is critical for improving the performance and reducing the cost of Li‒O 2 batteries. Herein we describe an ultraviolet-assisted synthesis method of preparing highly active and superb stable MXene-based electrocatalysts containing low Pt content. The obtained electrocatalysts feature homogenous Pt nanocrystals embedded within multilayer Ti 3 C 2 MXene (Pt‒Ti 3 C 2 ). Because of the improvement on electrical and catalytic properties and structural stability, this catalyst design enables promising electrochemical performance. Notably, at an ultralow Pt loading of 0.01 mg cm −2 cathode, the catalyst exhibits a high discharge capacity of 14,769 mAh/g Pt‒Ti3C2 , a low charge overpotential of 0.32 V, and excellent cycle performance over 100 cycles. Systematic studies reveal the relevancy between electrocatalytic performance and chemical microstructure, whereas the stable Pt‒Ti chemisorption facilitates the synergistic catalysis between Pt nanocrystals over multilayer Ti 3 C 2 substrates. Density functional theory reveals mechanistic insights into electrocatalytic effect on the reduction of charge overpotential, whereas the mild interaction between Pt‒Ti 3 C 2 and Li 2 O 2 monomer enables low charge overpotential.

Laser surface texturing of Ti/Cu/Ti and Ti/Cu/Zr/Ti multilayers thin films

Laser surface texturing of Ti/Cu/Ti and Ti/Cu/Zr/Ti multilayers thin films

In Vitro and Electrochemical Characterization of Laser-Cladded Ti-Nb-Ta Alloy for Biomedical Applications

Titanium (Ti) and its alloys are predominant choices for use as biomaterials in human implants. Research has shown the adverse effects of using commercial Ti alloy Ti-6Al-4V in the human body, and this presents a need for viable alternatives. In this study, Ti alloy Ti-17Nb-6Ta was manufactured by laser cladding—a prominent additive manufacturing (AM) technology. Laser cladded specimens were evaluated for their in vitro and electrochemical behavior. A human osteosarcoma cell line (MG-63 cells) was used for in vitro investigations. Cell proliferation was good in the physiological medium, and cells were alive when in contact with the laser cladded alloy, even after two to three weeks, indicating good cell viability and compatibility with this alloy. Electrochemical characterization was carried out in Ringer’s solution, and noticeably lower corrosion current density and corrosion rate values were observed. The lower amounts of these parameters indicated the passivation behavior due to multi-layer Ti, Nb, and Ta alloy oxide films. These oxide films also enhanced osseointegration. Thus, the Ti-17Nb-6Ta alloy can be an ideal biocompatible alternative to Ti-6Al-4V.

Microstructure, mechanical properties and biocompatibility of laser metal deposited Ti–23Nb coatings on a NiTi substrate

To simultaneously obtain superior superelasticity and biological properties, single- and multi-layer Ti–23Nb coatings were deposited on a cold-rolled NiTi substrate using laser metal deposition (LMD). The microstructure of the single-layer coating consisted of a cellular structure with a grid size of ∼300 μm in the eutectic layer, strip structures and prior β-(Ti, Nb) phases surrounded by the Ti2Ni(Nb) phase in the Ni diffusion zone. In contrast, the microstructure of the multi-layer coating consisted of α′, α′′, and prior β phases, which arise from the partition of Nb. Compared with the NiTi substrate, the Ni ion release concentration of the single-layer coating is reduced by 45% with similar nano-mechanical behavior, i.e. a nanohardness, H, of ∼4.0 GPa, a reduced Young's modulus, Er, of ∼65 GPa, an elastic strain to failure, H/Er, of ∼0.06, a yield stress, H3/Er2, of ∼0.016 GPa, and a superelastic strain recovery, ηsr, of ∼0.3. The reduction of Ni ion concentration for multi-layer coating after 35 days is even better at up to 62%, but at the cost of a degradation in the mechanical properties. The LMD coatings have a high dislocation density, and their creep is controlled by dislocation movement.

Microstructure and mechanical properties of micro-nano Ti2AlC-reinforced TiAl composites

In order to improve the mechanical properties of TiAl alloys, micro-nano Ti2AlC-reinforced TiAl composites were successfully fabricated by means of spark plasma sintering (SPS) using the ball-milled multilayer graphene oxide and Ti–48Al–2Nb–2Cr pre-alloyed powders. The micro-nano Ti2AlC phase precipitated at the interface between α2-Ti3Al and γ-TiAl phases utilizing the reaction of TiAl and high-activity graphene. Fully lamellar structure was obtained after sintering above 1300 °C, and Ti2AlC phase characteristic were depended on sintering temperature and graphene content. The compressive strength and fracture strain of TiAl-0.5G alloy were improved at room temperature and elevated temperature, which was improved by 23.61% and 5.03% compared to the TiAl-0G alloy at room temperature. The tribological properties of TiAl composites were significantly improved by micro-nano Ti2AlC at the room temperature, and the average friction coefficient of TiAl-0.5G alloy is 0.217 compared with TiAl-0G alloy is 0.312, and the wear mechanism is ploughing wear. The micro-nano Ti2AlC improves the strength and oxidation resistance of TiAl composites at 650 °C, which is detrimental to the wear resistance due to the lower ductility and the third wear by the loose oxide particles at elevated temperature.

The Properties of Zr, Ti, Al and Si Nitride-Based Multilayer Coatings Obtained By Cathodic Arc Plasma Deposition

The Properties of Zr, Ti, Al and Si Nitride-Based Multilayer Coatings Obtained By Cathodic Arc Plasma Deposition

Preparation of Ti&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;C&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; nanowires with cross-linked network structure and its application in lithium-sulfur batteries

<p indent="0mm">Lithium-sulfur batteries are considered as one of the most promising next-generation energy storage devices due to their high energy density and low cost, but their development and application still face many challenges such as the shuttle effect of lithium polysulfide. Recently, a new type of two-dimensional material, MXene (e.g., Ti₃C₂), has attracted much attention. The high specific surface area, high electrical conductivity and polar surface of Ti₃C₂ make it an ideal sulfur host for lithium-sulfur batteries. However, two-dimensional Ti₃C₂ nanosheets (Ti₃C₂-NS) are easy to aggregate together, which reduces the contact area between them and sulfur, and results in the performance degradation of the sulfur electrode. In this work, Ti₃C₂ nanowires (Ti₃C₂-NW) with cross-linked structure are successfully synthesized by etching the exfoliated Ti₃C₂ nanosheets in NaOH solution. Subsequently, sulfur-loaded Ti₃C₂-NW (Ti₃C₂-NW@S) is prepared by the melt-impregnation method and used as the positive electrode material for lithium-sulfur batteries. Scanning electron microscope (SEM) and transmission electron microscope (TEM) images show that Ti₃C₂-NW is composed of cross-liked nanowires with a width of <sc>5–10 nm,</sc> and sulfur particles are successfully loaded in the cross-linked network structure of Ti₃C₂-NW. Moreover, the EDX element mapping images show that the elemental distribution of S is consistent with those of C, O and Ti, further confirming the high dispersion of sulfur particles in Ti₃C₂-NW. Subsequently, Ti₃C₂-NW is characterized by using nitrogen adsorption and desorption technique. The type IV isotherm indicates that Ti₃C₂-NW has a mesoporous structure and its specific surface area is <sc>124.6 m² g⁻¹.</sc> XPS analysis proves the interaction between Ti atoms on the surface of Ti₃C₂-NW and S atoms from sulfur particles because of the presence of Ti-S peak in the high-resolution Ti 2p and S 2p XPS spectra. The loading of sulfur in Ti₃C₂-NW@S (~71 wt%) is determined by thermogravimetric analysis (TGA). It is also found that the type of Ti₃C₂ precursor used for etching affects the structure of the product. Selecting the multilayer Ti₃C₂ particles as the Ti₃C₂ precursor for etching in NaOH solution can only obtain the composite of Ti₃C₂ nanowires and nanosheets (Ti₃C₂-NWS). For comparison, sulfur-loaded Ti₃C₂-NS (Ti₃C₂-NS@S) and sulfur-loaded Ti₃C₂-NWS (Ti₃C₂-NWS@S) are prepared and used as the positive electrode material for lithium-sulfur batteries. The cyclic voltammogram of Ti₃C₂-NW@S shows two reduction peaks and an oxidation peak, corresponding to lithiation of sulfur. Note that the potential difference of redox peak of Ti₃C₂-NW@S is smaller than that of Ti₃C₂-NWS@S, implying the smaller electrode polarization and faster redox reactions of sulfur within Ti₃C₂-NW. The electrochemical impedance spectroscopy (EIS) test results show that Ti₃C₂-NW@S has lower charge transfer resistance (<italic>R</italic>_ct = 7.35 Ω) than Ti₃C₂-NWS@S (<italic>R</italic>_ct = 28.38 Ω), also revealing the rapid reaction of sulfur with Li⁺ on Ti₃C₂-NW. Accordingly, compared to Ti₃C₂-NS@S and Ti₃C₂-NWS@S, Ti₃C₂-NW@S exhibits better electrochemical performance, such as a reversible capacity of <sc>658 mA h g⁻¹</sc> at <sc>0.2 C</sc> after 100 cycles, and a capacity of <sc>436 mA h g⁻¹</sc> at <sc>1 C</sc> after 300 cycles. The superior electrochemical performance of Ti₃C₂-NW@S is attributed to the large specific surface area and mesoporous structure of Ti₃C₂-NW@S, which effectively provide the space for high loading of sulfur and accommodate the volume expansion of sulfur during the lithiation process. Moreover, the large surface area of Ti₃C₂ nanowires is conducive to capturing the lithium polysulfide and thereby suppressing the shuttle effect of lithium polysulfides. Meanwhile, the cross-linked structure is also favorable to the diffusion of lithium ions. This study shows that modifying the morphology and structure of Ti₃C₂ can effectively improve its electrochemical performance as the sulfur host for lithium-sulfur batteries and expand its application in other energy fields.

Development of Actuators for Repairing Cracks by Coating W Wires with Reactive Multilayers.

The aim of this research work was to optimize the coating of tungsten wires with reactive multilayer thin films and promote an exothermic self-propagating reaction. The ultimate goal is to use this heat to liquify low melting temperature materials, and thus block crack propagation in metallic materials. Ni/Me (Me = Al, Ti) multilayers were deposited by a DC (direct current) magnetron sputtering onto tungsten wires with diameters of 0.05 and 0.20 mm. The depositions were carried out to obtain films with near equiatomic average chemical composition and a modulation period (bilayer thickness) between 20 and 50 nm. The cross-section of the films was analyzed using electron microscopy before and after electrical ignition. A new substrate holder was developed to improve the quality of the Al/Ni films, allowing a reduction in the defects previously observed. The Ni/Ti thin films showed no discernible defects, regardless of the substrate holder. However, after ignition, the Ni + Ti reaction occurred in a non-self-propagating mode. Passing an electric current through a wire (ϕ = 0.05 mm) coated with an Al/Ni thin film, promoted a flash of light that was associated with the start of a self-propagating reaction. The reaction product was a B2-AlNi intermetallic phase. W wires coated with reactive multilayers may contribute to crack filling, and have potential to be self-healing actuators.