Vapor Deposition Research Articles

Enhanced Friction and Wear Properties of TiN/MoS2 Composite Coating on the Surface of Plasma Nitrided Ti6Al4V Alloy

In this study, plasma nitriding and multi-arc ion plating techniques were employed to enhance the load-bearing capacity of the TC4 alloy. The tribological properties were characterized, and the mechanisms were discussed in detail. Subsequently, the tribological properties of the coating enhanced with MoS2 were then evaluated, and the results indicated that the plasma nitriding treatment, which exhibited optimal friction performance, resulted in the formation of a nitrided layer with a thickness of 98 μm on the surface of the TC4 alloy, thereby significantly improving its mechanical properties. Furthermore, the TiN coating samples treated with plasma nitriding demonstrated superior mechanical properties, achieving the highest hardness value (20 GPa), high load-carrying capacity (58 N) and the lowest wear rate (9.16 × 10−6 mm3·N−1·m−1). Moreover, the tribological properties of MoS2 deposited on the surface of the PN-2/TiN sample were significantly enhanced, which can be attributed to the synergistic effect of the excellent load-bearing characteristics of the plasma nitriding treatment and the wear resistance of the TiN layer. This study investigates the factors contributing to the superior tribological performance of the PN-2/TiN sample and the extended friction lifetime of the PN-2/TiN/MoS2 sample. The composite coating provides a new method to improve the anti-friction of soft metals, especially titanium alloys, and is expected to be applied in the aerospace field.

Mesoscale Filamentous Polyelectrolytes: Chemical Functionalization and Fluidic Structure.

The preparation and study of synthetic mesoscale structures opens opportunities to understand soft materials properties at length scales that are intermediate between that of the molecular and bulk, often referred to as the mesoscale. This paper details the preparation of mesoscale polymer filaments, prepared by flow coating and evaporative deposition from solution to yield filamentous versions of charged polymers. Using thiol-ene reactions on olefin-containing mesoscale polymer ribbons, anionic character in the form of carboxylates is introduced to the filamentous structures. The resultant mesoscale ribbons exhibit morphological changes as a function of their aqueous solution environment, based on their neutral versus anionic character, offering insights into the structure and morphology of small, multi-length scale, soft structures comprised of macromolecular materials.

A Novel (AlCrNbTaTi)N Multilayer Hard High-Entropy Alloy Nitride Coating with Variable Aluminum Content Deposited by Cathodic Arc Ion Plating

Traditional binary coatings like TiN and CrN display limited thermal stability and wear resistance under extreme conditions. High-entropy alloy nitride (HEAN) coatings offer a promising solution due to their customizable composition and unique properties, including high hardness, corrosion resistance, and thermal stability. This study focused on (AlCrNbTaTi)N HEAN coatings to address a critical need for materials capable of enduring extreme mechanical and tribological demands by examining the impact of aluminum content on their structural and mechanical properties, providing insights for optimizing coatings in harsh conditions through a self-assembled nanolayer structure with enhanced resilience and performance. The coatings were deposited via a cathodic arc by employing an AlCrNbTaTi alloy target composed of aluminum (20, 50, 60, 70%) and equal molar ratios of Cr, Nb, Ta, and Ti. The coatings were characterized through grazing incidence X-ray diffraction, SEM, HR-TEM, a nano-indentation test, and a friction and wear test. The results indicated that with increasing Al content, the structure of (AlCrNbTaTi)N coatings shifted from FCC to an amorphous state, leading to a reduction in the hardness and elastic modulus, accompanied by an increase in the wear rate and friction coefficient. The (AlCrNbTaTi)N coating, with an equal atomic ratio of metallic elements, showed potential as a hard tool coating. It demonstrated outstanding mechanical and tribological properties, with a 34.5 GPa hardness, 369 GPa modulus, 0.35 friction coefficient, and 8.2 × 10−19 m2·N−1 wear rate. The findings highlight the potential of (AlCrNbTaTi)N coatings to extend tool life and improve operational efficiency, helping advance materials engineering for industrial applications.

A Concise Review on Magnetic Nanoparticles: Their Properties, Types, Synthetic Methods, and Current Trending Applications

: In recent years, there has been significant research on developing magnetic nanoparticles (MNPs) with multifunctional characteristics. This review focuses on the properties and various types of MNPs, methods of their synthesis, and biomedical, clinical, and other applications. These syntheses of MNPs were achieved by various methods, like precipitation, thermal, pyrolysis, vapor deposition, and sonochemical. MNPs are nano-sized materials with diameters ranging from 1 to 100 nm. The MNPs have been used for various applications in biomedical, cancer theranostic, imaging, drug delivery, biosensing, environment, and agriculture. MNPs have been extensively researched for molecular diagnosis, treatment, and therapeutic outcome monitoring in a range of illnesses. They are perfect for biological applications, including cancer therapy, thrombolysis, and molecular imaging, because of their nanoscale size, surface area, and absence of side effects. In particular, MNPs can be used to conjugate chemotherapeutic medicines (or) target ligands/proteins, making them beneficial for drug delivery. However, up until that time, some ongoing issues and developments in MNPs include toxicity and biocompatibility, targeting accuracy, regulation and safety, clinical translation, hyperthermia therapy, immunomodulatory effects, multifunctionality, and nanoparticle aggregation.

Microstructure and high temperature tribological properties of arc ion plated CrN and CrAlN coatings on AISI H13 steel

Purpose The purpose of this study to investigate the high temperature tribological performances of CrN and CrAlN coatings on AISI H13 steel, which was beneficial to improve the wear resistance of hot work molds. Design/methodology/approach Arc ion plating was used to deposit the CrN and CrAlN coatings on AISI H13 steel, and the tribological performances of CrN and CrAlN coatings were evaluated using a ball-on-plate wear tester. Findings The average coefficients of friction and wear rate of CrAlN coating in the normal wear period are 0.33 and 5.34 × 10–9 mm3·N–1·mm–1, respectively, which are lower than those of CrN coating, exhibiting that the outstanding friction reduction. The formations of Cr and Al oxides during the wear process are the main factor in enhancing the tribological performance of CrAlN coating. Originality/value CrN and CrAlN coatings were applied for hot work molds, and their tribological performances were comparatively investigated. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2024-0359/

The Preparation of Nano-Titanium Dioxide and Its Healthcare Effects in Cosmetics

Cosmetics are an integral part of daily life. Nowadays, cosmetics are endowed with more healthcare functions while meeting people's needs for beauty enhancement. Nano-titanium dioxide plays a crucial role in their formulation because of its antibacterial and anti-inflammatory properties. As a new type of nanomaterial, nano-titanium dioxide has excellent properties. This paper explores the properties, preparation methods, applications, and potential hazards associated with nano-titanium dioxide in cosmetics. The study highlights its strong ultraviolet (UV) shielding capabilities, which are used in sunscreen products. The nano-titanium dioxide has good dispersibility and weather resistance. The preparation methods included sol-gel, hydrothermal, vapor deposition, and oxide reduction methods. The paper further discusses the use of nano-titanium dioxide in various cosmetic products such as sunscreens, lotions, and gels. Despite its advantages, the paper also displays safety concerns related to skin exposure, inhalation, and oral intake of nano-titanium dioxide. The material poses certain risks, its beneficial properties make it a valuable component in the cosmetic industry. The nano-titanium dioxide significantly enhances the functionality of cosmetics. This work contributes to its widespread use in the future.

Effect of Ion-Assisted Deposition Energy of RF Source on Optical Properties, Microstructure, and Residual Stress of HfO2 Thin Films

HfO2 thin films were prepared using radio frequency (RF) ion source-assisted deposition, and the effects of auxiliary ion energy on the microstructure, optical properties, and residual stress of the films were systematically studied. The experimental results showed that when the auxiliary ion energy increased, the extinction coefficient, compressive stress, and optical band gap were gradually increased. These changes were attributed to increased grain boundary defects, crystal structure disorder, and grain size decrease due to high-energy ion bombardment. The HfO2 films deposited at a lower ion energy (600 V) exhibited higher surface quality (RMS = 0.78 nm), better optical properties (k = 10⁻5), and lower residual stress (1.26 GPa).

Exploring the Broad Spectrum of Titanium-Niobium Implants and Hydroxyapatite Coatings-A Review.

Tooth loss replacement using dental implants is becoming more frequent. Traditional dental implant materials such as commercially pure titanium and titanium aluminum vanadium alloys have well-proven mechanical and biological properties. New titanium alloying metals such as niobium provide improved mechanical properties such as lower elastic modulus while displaying comparable or even better biocompatibility. Hydroxyapatite coatings are a well-documented and widely used method for enhancing dental implants' surface characteristics and properties and could provide a useful tool for further enhancing titanium-niobium implant properties like osteointegration. Among several coating techniques, physical deposition methods and, in particular, vapour deposition ones are the most used due to their advantages compared to wet deposition techniques for hydroxyapatite coating of metallic surfaces like that of dental implants. Considering the scarcity of data concerning the in vivo evaluation of titanium-niobium biocompatibility and osteointegration and the lack of studies investigating coating these new proposed alloys with hydroxyapatite, this review aims to further knowledge on hydroxyapatite-coated titanium niobium alloys.

Cu3P/CoP Heterostructure for Efficient Electrosynthesis of Ammonia from Nitrate Reduction Reaction.

Electrocatalytic nitrate reduction (ENO3RR) for ammonia production is one of the potential alternatives to Haber-Bosch technology for the realization of artificial ammonia synthesis. However, efficient ammonia production remains challenging due to the complex electron transfer process in ENO3RR. In this study, we fabricated a Cu3P/CoP heterostructure on carbon cloth (CC) by electrodeposition and vapor deposition, which exhibits an exceptional ENO3RR performance in alkaline medium, and showcases a Faradaic efficiency of ammonia (FENH3) and an ammonia yield rate as high as 97.95% and 17,637.3 μg h-1 cm-2 at -0.9 V vs RHE. Moreover, Cu3P/CoP also has excellent catalytic activity for nitrite reduction to ammonia, with an FENH3 up to 98.31% at -0.7 V vs RHE. The experimental and theoretical calculations reveal and confirm that the formation of a heterogeneous interface between Cu3P and CoP effectively promotes the electron transfer, where Cu3P as an electron donor induces the decrease of electron density around Cu and results in an enhancement of NO2- adsorption, thereby accelerating the ENO3RR process while inhibiting the competitive hydrogen evolution reaction (HER). Moreover, the metal phosphide catalyst facilitates the water dissociation, which accelerates the abundant *H generation, thus enhancing the subsequent hydrogenation process toward ENO3RR.

Initial stages of rejuvenation of vapor-deposited glasses during isothermal annealing: Contrast between experiment and simulation.

Physical vapor deposition can prepare organic glasses with high kinetic stability. When heated, these glassy solids slowly transform into supercooled liquid in a process known as rejuvenation. In this study, we anneal vapor-deposited glasses of methyl-m-toluate for 6h at 0.98Tg to observe rejuvenation using dielectric spectroscopy. Glasses of moderate stability exhibited partial or full rejuvenation in 6h. For highly stable glasses, prepared at substrate temperatures of 0.85Tg and 0.80Tg, the 6h annealing time is ∼2% of the estimated transformation time, and no change in the onset temperature for the α relaxation process was observed, as expected. Surprisingly, for these highly stable glasses, annealing resulted in significant increases in the storage component of the dielectric susceptibility, without corresponding increases in the loss component. These changes are interpreted to indicate that short-term annealing rejuvenates a high frequency relaxation (e.g., the boson peak) within the stable glass. We compare these results to computer simulations of the rejuvenation of highly stable glasses generated by using the swap Monte Carlo algorithm. The in silico glasses, in contrast to the experiment, show no evidence of rejuvenation within the stable glass at times shorter than the alpha relaxation process.

Influence of Molybdenum Addition on the Structure, Mechanical Properties, and Cutting Performance of AlTiN Coatings

Though AlTiN coating has been intensively studied, there is still a need to develop AlTiN coating to meet the growing demand of industrial machining. One effective way to improve the performance of AlTiN coating is by adding alloying elements. In this study, AlTiN and AlTiMo coatings were deposited using multi-arc ion plating to investigate the influence of molybdenum addition on the structure, mechanical properties, and cutting performance of AlTiN coatings. Spherical droplets formed on the surfaces of both coatings, with the AlTiMoN coating exhibiting more surface defects than the AlTiN coating. The grazing incidence X-ray diffraction results revealed the formation of an (Al,Ti)N phase formed in the AlTiN and AlTiMoN coatings. Molybdenum doping in the AlTiMoN coating slightly reduced the grain size. Both coatings exhibited excellent adhesion to the substrate. The hardness (H), elastic moduli (E), H/E, and H3/E2 ratios of the AlTiMoN coating were higher than those of the AlTiN coating. The improvement in the mechanical properties was attributed to grain refinement and solution strengthening. Molybdenum doping improved the tribological properties and cutting performance of the AlTiN coatings, which was ascribed to the formation of MoO3 as a solid lubricant. These results show a path to increase the performance of AlTiN coating through molybdenum addition and provide ideas for the application of AlTiMoN coatings for cutting tools.

Thermal erosion behavior of electroplating and multi-arc ion plating Cr coatings on PCrNi3MoVA steel

Abstract The thermal erosion behavior of two-kind Cr coating on PCrNi3MoVA steel under 350 MPa erosive pressure is compared. Microscopic observations and elemental analyses of the two-kind Cr coatings are carried out by scanning electron microscopy (SEM) and energy dispersion spectrometer (EDS), which led to their exfoliation mechanism. It is found the spalling mechanism of the two-kind Cr coatings after thermal erosion is different: the spalling of the electroplating Cr coating is in the form of localized delamination to overall spalling over a large area, and the spalling of the multi-arc ion plating Cr coating is in the form of horizontal and vertical extended spalling. The results show that the electroplated Cr coating has weaker erosion resistance than the multi-arc ion plating Cr coating and the Cr coating by multi-arc ion plating is more suitable as a protective layer to extend the life of the gun barrel.

A Review of Nanostructure Coating Techniques to Achieve High-Precision Optical Fiber Sensing Applications

Optical fiber sensors have emerged as a critical sensing technology across various fields due to their advantages, including high potential bandwidth, electrical isolation that is safe for utilization in electrically hazardous environments, high reliability, and ease of maintenance. However, conventional optical fiber sensors face limitations in achieving high sensitivity and precision. The integration of nanostructures with advanced coating technology is one of the critical solutions to enhancing sensor functionality. This review examined nanostructure coating techniques that are compatible with optical fiber sensors and evaluated etching techniques for the improvement of optical fiber sensing technology. Techniques such as vapor deposition, laser deposition, and sputtering to coat the nanostructure of novel materials on the optical fiber sensors are analyzed. The ability of optical fiber sensors to interact with the environment via etching techniques is highlighted by comparing the sensing parameters between etched and bare optical fibers. This comprehensive overview aims to provide a detailed understanding of nanostructure coating and etching for optical fiber sensing and offer insights into the current state and future prospects of optical fiber sensor technology for sensing performance advancement, emphasizing its potential in future sensing applications and research directions.

The Formation Mechanisms of np-Fe in Lunar Regolith: A Review.

Nanophase iron (np-Fe) is widely distributed on the surface of lunar soil particles, forming as a result of space weathering. These np-Fe particles contribute to the reddening and darkening of the visible to near-infrared spectra of weathered lunar material and serve as critical indicators for assessing the maturity of lunar soil. (1) This article reviews the proposed formation mechanisms of np-Fe particles from studies of Apollo and Luna soils, including the thermal reduction of iron melts, vapor deposition caused by micrometeorite impacts, and hydrogen reduction due to solar wind exposure. (2) Additionally, recent findings from the analysis of Chang'E-5 lunar soil are highlighted, revealing new mechanisms such as sub-solidus decomposition of olivine, impact-driven disproportionation, and FeO eutectic reactions. (3) Experimental studies simulating space weathering through laser and ion irradiation are also discussed and compared. Despite extensive research, a definitive understanding of np-Fe particle formation remains elusive. Previous lunar soil samples have been collected from the near side of the Moon. This year, the Chang'E-6 mission has successfully returned the first-ever lunar soil samples from the far side. These samples are expected to exhibit unique space weathering characteristics, providing new insights into the formation mechanisms of np-Fe in lunar soil.

Spectrometers of Neutrons and Fast Atoms of Tokamak Thermonuclear Plasma Based on CVD Synthesized Diamond Single-Crystal Films

High radiation resistance, chemical inertness, the ability to operate at elevated temperatures, high mobility and efficiency of charge-carrier collection are important properties of diamond for designing detectors and spectrometers of ionizing radiation. Currently, diagnostics of neutrons and neutral particle fluxes based on diamond detectors for the ITER thermonuclear reactor are justified and developed. This work presents the results of a Raman spectroscopy and photoluminescence spectroscopy study of the electronic quality of synthesized epitaxial diamond films obtained by vapor deposition in a hydrogen and methane mixture in the ARDIS reactor on boron-doped single-crystal diamond substrates. To confirm their electronic quality, detectors have been made from films selected by spectrometric methods and the charge collection efficiency and energy resolution have been measured when irradiated with alpha particles from a 241Am source and 14.7 MeV fast neutrons from the ING-07T2 neutron generator.

A High-Sensitivity Fiber Optic Soil Moisture Sensor Based on D-Shaped Fiber and Tin Oxide Thin Film Coatings.

We present a high-sensitivity fiber optic soil moisture sensor based on side-polished multimode fibers and lossy mode resonance (LMR). The multimode fibers (MMFs), after side-polishing to form a D-shaped structure, are coated with a single-layer SnO2 thin film by electron beam evaporation with ion-assisted deposition technology. The LMR effect can be obtained when the refractive index of the thin film is positive and greater than its extinction coefficient and the real part of the external medium permittivity. The D-shaped fiber optic soil moisture sensor was placed in soil, allowing moisture to penetrate into the thin film microstructure, and it observed the resonance wavelength shift in LMR spectra to measure the relative humidity change in soil. Meanwhile, an Arduino electronic soil moisture sensing module was used as the experimental control group, with soil relative humidity ranging from 10%RH to 90%RH. We found that the D-shaped fiber with a residual thickness of 93 μm and SnO2 thin film thickness of 450 nm had a maximum sensitivity of 2.29 nm/%RH, with relative humidity varying from 10%RH to 90%RH. The D-shaped fiber also demonstrates a fast response time and good reproducibility.

(Digital Presentation) Nanoscale Sculpturing of Al and Al Alloys for Heterogeneous Al-Cu Joints

Heterogeneous Al-Cu joints are nowadays generated in a huge variety of different techniques depending on the intended application, such as corrosion protection of Al components, electric connections with improved interfaces, or even lightweight current collectors for batteries. Four major techniques are commonly used that can be further subdivided into cladding (including roll cladding, thermo-compression bonding, friction welding etc.), vapor deposition (including PVD, CVD etc.), thermal spraying and chemical plating (including electroless and electrochemical plating). Each of the methods offers certain advantages and disadvantages for the formation of Al-Cu joints. Typically observed disadvantages are the formation of intermetallic Al-Cu compounds (IMC), higher electric resistivity, a rather low mechanical strength under static or cyclic mechanical load conditions.The present work follows the electrochemical route to form Al-Cu joints utilizing nanoscale sculpturing of the Al substrate [1] as a starting point to overcome these above described typically observed disadvantages of Al-Cu joints. The resulting nanoscale sculptured Al-Cu joint is intensively characterized with respect to its structural (see Fig. 1), chemical and mechanical properties. It was found that such Al-Cu joints offer a high mechanical load bearing capability because of the interlocking zone between Al and Cu offering a gradual change, so that an optimum stress transfer can occur without the risk of a stress pile-up at the interface between both metals.Furthermore, no intermetallic Al-Cu phases grow at the interface between Al and Cu during deposition which could mechanically weaken the joint due to embrittlement, especially under cyclic loading conditions. Another advantage is the absence of Al-Cu intermetallics in the joint, being of great importance if high current or high voltage applications are intended.Fig 1: Nanoscale sculptured Al surface with cubic interlocking surface structures in cross-section (left) and cross-sectional view on Al-Cu joint after electrochemical Cu deposition on nanoscale sculptured Al surface (right).[1] M. Baytekin-Gerngross, M.D. Gerngross, J. Carstensen, and R. Adelung, Nanoscale Horizon 1(6), 467 (2016). Figure 1

Photobioelectrodes through Photopolymerization of Pyrrole by Photosystem I

Conductive polymers can be used to wire biomolecules with man-made materials to create hybrid composites that exhibit synergistic properties, particularly in regard to photoactivity. Photosystem I (PSI), a protein isolated from the photosynthetic chain in green plants, can be interfaced with such polymer networks to utilize the photoactivity of PSI to power light-driven reactions. The conductive polymers aid the protein’s performance by providing pathways for the electrons to be shuttled to and from the active sites. One of the primary challenges in wiring PSI to conductive polymers lies in properly aligning the active sites with the conductive material. A variety of approaches have been used to solve this problem, such as vapor deposition and electropolymerization. Recently, we showed how PSI could be utilized to photopolymerize conductive polymers in direct contact with one of the active sites. Building upon this previous work, we show how a composite film can also be obtained through a similar photopolymerization process, while yielding a product much closer to the electropolymerization entrapment scheme where proteins are entrapped within the polymer network. These composite films demonstrate how the system’s photoactivity can be greatly improved through the direct photopolymerization connections, bringing the field even closer to more practical and efficient PSI applications.

Thin Film Electrocatalysts on Extended Surface Supports for the Oxygen Reduction Reaction

The world is urgently looking to increase the amount of renewable energy power generation and reduce carbon emissions. Proton exchange membrane water electrolyzers (PEMWE) and fuel cells (PEMFC) play important roles in energy storage and help leveling the renewable power generation. Platinum group metals (PGMs) are popular catalysts used in PEMWE and PEMFC. However, the cost of PGMs hinders the widespread adoption of these two devices and slows down the progress of decarbonizing industrial sectors. In this talk, the oxygen reduction reaction (ORR) performance of platinum (Pt) catalysts, fabricated via different thin film deposition technologies will be compared to Pt catalysts prepared via traditional incipient wetness impregnation (IWI). Pt catalysts fabricated via thin film deposition technology, such as e-beam evaporation, sputtering, and atomic layer deposition (ALD), demonstrate higher mass activity and electrochemical surface area (ECSA) compared to Pt catalysts fabricated using IWI. This result points out the possible option to make PEMFC and PEMWE more affordable and provides alternate methods for researchers to finely control the loading of the Pt in device electrodes.

Vanadium Oxide Device with Tunable Oxygen Vacancy Concentration for Neuromorphic Computing

Analog, non-volatile memories that can enable in-memory data processing are attractive for exploring non-von-Neumann architectures to realize substantially more efficient computing for AI applications. Among the various device concepts, NVMs based on tuning of point defects via insertion of ions such as alkali metals, protons, or oxygen vacancies are attractive due to the ability to finely tune the electronic conductivity by controlling the defect concentration. Previously, oxygen vacancy concentration in vanadium oxide (VO2-x) has been linked to electronic conductivity and the insulator-to-metal transition temperature. However, while previous studies have mainly concentrated on single crystal epitaxial films of VO2, polycrystalline films deposited by technique compatible with Si back end of the line (BEOL) fabrication scheme are considerably easier to integrate with CMOS circuitry. We employ two distinct approaches for device integration of VO2-x thin films: (1) an electron beam evaporation deposition of bulk vanadium (V) precursor followed by annealing in an oxygen (O2) environment, and (2) reactive sputtering of vanadium oxide followed by annealing in air. Raman spectroscopy reveals the presence of VO2 and V2O5 phases, with differing ratios indicative of device conductance states [Figure 1b].1 Previous research has demonstrated that the characteristics of VO2 insulator to metal transition (IMT) can be adjusted by manipulating oxygen vacancy concentration using an electrolyte.2 However, the presence of the electrolyte interface can introduce noise due to uncontrolled parasitic reactions. To mitigate this issue, our study utilized electron beam irradiation to deliberately induce vacancies in the VO2 without relying on an electrolyte. This controlled alteration of the device state was found to lead to a significant change in noise levels, particularly when the device was in proximity to the IMT transition temperature.The analysis of our films provides detailed structural and compositional dynamics of VO2-x and V2O5 phases which exhibit analog synaptic and threshold tunability with remarkable state retention2 [Figure 1cd]. This abstract provides a comparative analysis of these approaches, focusing on their respective advantages and disadvantages in the context of vanadium oxide based analog device fabrication.