Deposition Procedure Research Articles

Titania-Based Coral-Structured Solar Absorber Coating with Improved Scalability and Durability at High Temperature.

Solar energy harvesting and storage are essential in the future mix of renewable energy technologies. Hierarchical coral-structured coatings have been shown to yield high solar absorptance in concentrating solar thermal (CST) systems. However, interfacial delamination and scalability challenges owing to material complexity pose significant hurdles for the widespread industrial adoption of these hierarchical CST coatings. Here, a coral-structured coating is proposed whose black pigments are strongly bonded by titania, which is a material that mitigates interfacial delamination. Importantly, this coating follows a facile deposition procedure suitable for large-scale solar receivers. The drone-deposited coating inhibits cation diffusion and maintains a stable solar absorptance of even after long-term (3000 h) high-temperature ( ) aging. The scalability of developed coating represents a substantial advancement in the implementation of light-trapping enhancement and maintenance approaches across a wide range of CSTapplications.

An Emerging Strategy in Sequential Synthesis of Catalyst and Carbon Nanotube Foams by Employing a Chemical Vapor Deposition Procedure: Structural Evaluation and Growth Mechanism

An Emerging Strategy in Sequential Synthesis of Catalyst and Carbon Nanotube Foams by Employing a Chemical Vapor Deposition Procedure: Structural Evaluation and Growth Mechanism

Preparing a binder-free cathode composed of NMC811/sulfonated reduced graphene oxide sheets/carbon black via in-situ electrophoretic deposition to enhance cyclability of Li-ion batteries

Disruption in the restacking of the graphene present in the electrodes could hamper the reduction in the conductivity and also the surface area, which may be a good reason why graphene has not yet performed as predicted. In this research, we employed the scalable electrophoretic deposition (EPD) procedure to make instantly a binder-free Li-ion battery cathode, consisting of LiNi0.8Mn0.1Co0.1O2 (NMC811), sulfonated reduced graphene oxide (SRGO) sheets, and carbon black (CB) particles. The EPD process caused a squeezing force, which not only wrapped the SRGO sheets around the NMC811 nanoparticles, but also inserted the CB particles into the composite in an electrostatically stabilized combination. As evidenced by the electrochemical measurements, the binder-free NMC/SRGO/CB electrode manifested better cycling performance at the current density of 0.2 C, where this electrode delivered discharge capacities of 170.3 and 143.7 mAh g−1, respectively, at the 1st and 200th cycle compared to discharge capacities of 162.3 and 122.6 mAh g−1 acquired for the NMC/SRGO electrode. The excellent cycle stability and rate capability of the optimized binder-free NMC/SRGO/CB cathode can be attributed to withstanding the volume expansion of the active particles during cycling due to wrapping graphene sheets, inhibition of the restacking of graphene sheets by sulfonated groups and CB spacers, electrostatic interaction between sulfonated groups and lithium ions, and efficient electrolyte infiltration by ion and electron conductive channels in the binder-free cathode structure.

Surface Coating of Nickel-Titanium (Ni-Ti) Pediatric Rotary File Using Graphene Oxide: A Scanning Electron Microscopy Analysis.

The effectiveness of endodontic files relies significantly on the characteristics of the outermost layer, which can be greatly improved through suitable surface treatments and appropriate coatings. Graphene-based materials (GBMs) have been utilized to fabricate nanocomposite coatings aimed at improving surface characteristics and mechanical behavior, including resilience, sustainability, oxidation resistance, solidity, and traction. This research aims to study the surface topography of a nickel-titanium (Ni-Ti)pediatric rotary file coated with graphene oxide (GO) using a scanning electron microscope (SEM). The study utilized Ni-Ti pediatric rotary instruments that were 16 mm long and had the same ISO tip size of #25. The Ni-Ti pediatric rotary files had a titanium oxide coating that needed to be removed for the application of the GO coating. The GO coating was applied to the files using an electrophoretic deposition(EPD) procedure. Data were gathered to evaluate the surface topography and structural profiles of the GO-coated endodontic files through SEM analysis. SEM imaging showed that the GO coatings consisted of numerous layers of GO sheets, which were uniformly and thoroughly applied to the endodontic instrument. A substantial portion of the GO layers aligned with neighboring layers along the edges, creating a continuous structure. GO coatings were effectively applied to Ni-Ti endodontic instruments using EPD. The deposition of the GO coating is consistent throughout the surface of the Ni-Ti rotary instrument.

Sonochemical deposition of gold nano-shells on suspended polymeric spheres

Metal nanoparticles have drawn great interest due to their unique properties for applications in the fields of catalysis, biomedicine and environmental science depending on the architecture of the metal nanoparticle composites. Amongst different designing routes, the chemical template deposition offers great flexibility in terms of the template selection and interfacial interactions, giving rise to controllable designs. In order to control over nanoparticle size distribution and deposition efficiency, a sonochemical approach has been systematically followed in this study. Key parameters of the ultrasound-assisted deposition procedures during the seeding step to synthesise gold nanoparticle-coated poly(styrene) beads were investigated. The impact of the solution pH and the ultrasonic frequency on the template deposition was examined at 139, 300, 500 and 1000 kHz. The results, monitored by transmission electron spectroscopic imaging, show that the highest gold deposition was achieved at 300 kHz, revealing the mechanistic details of the nucleation-crystal growth behaviour as a function of ultrasonic frequency and reaction time. In addition, the concentration ratio between gold ions and poly(styrene) beads was varied. The highest deposition coverage and smallest particle size were reached at 0.05 mM and 2.5 mg, respectively. The proposed mechanism of the MNPs formation and deposition behaviour were then discussed based on the tested parameters.

Hybrid Molecular Layer Deposition of Molybdenum-Aminates as Hydrogen Evolution Reaction Electrocatalysts

The development of high-performance hydrogen evolution reaction (HER) electrocatalysts from noble metal-free materials is critical to achieving cost-effective water splitting and ultimately realizing affordable hydrogen based on renewable energy. Compounds based on earth-abundant transition metals have been the subject of great research interest for this purpose, with metal nitrides gaining recent attention due to their high conductivity and corrosion resistance. Molybdenum nitride-based electrocatalysts have shown particular promise, with many of the best reported activities occurring in composite systems wherein crystalline MoNx domains are embedded in an amorphous N-doped carbon matrix. The present work demonstrates the formation of such uniquely active morphologies in films deposited by organic-inorganic hybrid molecular layer deposition (MLD).Hybrid MLD is a hybridization of other well-established layer-by-layer deposition techniques – namely atomic layer deposition (used to deposit inorganic films) and purely organic MLD. This family of techniques involves the cyclical exposure of a growth surface to alternating vapor-phase chemical precursors which react in a self-limiting fashion to saturate available surface sites, offering atomic- and molecular-level control over the resulting films. This presentation will introduce the successful development of hybrid MLD deposition procedures for new Mo-aminate materials using Mo(CO)6 as a Mo precursor and various amine precursors, including ethylenediamine, p-phenylenediamine, and tris(2-aminoethyl)amine.We will describe how the molecular level of control offered by this technique enables tunable variations in film composition and structure, lending unique insights into how the local bonding environment of Mo active sites affects their catalytic properties towards HER. Increased nitrogen loading in the MLD films was shown to decrease the overpotentials required to drive HER in acidic media (0.5 M H2SO4) and improve film stability. Catalysts with N/Mo ratios above 2 demonstrated the best performance, with overpotentials lower than 400 mV at -10 mA/cm2. By incorporating organic components in the MLD films, it was possible to induce desirable morphological changes in the catalytic material – notably including the development of increased active site density – simply through initial exposure to HER testing conditions. The choice of organic precursor affected the rate and extent of these changes through structural effects like crosslinking and crystallinity, which led to more stable catalysts, slowed the rate of morphological changes, and impacted final film structure.

Investigating laser power in AM-LMD process on the Inconel 718 powder deposited profile microstructure, aiming to repair gas turbine blades

ABSTRACT The purpose of this study was to evaluate the feasibility of repairing defective turbine blades made of Inconel 738 using additive manufacturing called laser metal deposition with the use of Inconel 718 powder. The deposition process was conducted on substrates using varying laser power, 150, 250 and 350 (W). The experimental results indicate that as the laser power is raised, there is a corresponding increase in the average of substrate melting depth, 33.42–405.12 (µm), the average of interface thickness, 2.85–10.20 (µm) and the amount of dilution, 0.036–0.684 (%). The substrate's volume percentage and the average size of the γ’ phase exhibit larger values prior to the deposition procedure compared to the subsequent stages. The augmentation of laser power resulted in a proportional rise in both the volume percentage and average size of the γ’ phase within the substrates. At the location near the interface of the first layer, graining is preferentially in the direction of heat transfer and crystal growth. A narrow unmixed zone was formed along the melting line in the substrate and first layer’s interface, that whit increased laser power, area of this zone decreased, 7.27 to almost 0 (µm). As the layers approach the surface, the grains become unidirectional and coaxial growth. Increasing the laser power increased the average grain size of the layers.

Chemically activated Ag-embedded bridged-layer for copper pattern addition on PET film

This article describes a chemically activated method for copper addition on polyethylene terephthalate (PET) films with robust reliability and easy process. Thereof, a bridging layer produced by compatible composite of inorganic AgNO3 and organic epoxy resin (ER) in propylene glycol methyl ether (PM) solvent, was coated on the PET. It was chemically activated when immersed in acetone reagent and sodium borohydride solution, and accordingly the AgNO3 was reduced into Ag monomers as copper catalysts in the next chemical deposition procedure. The as-catalyzed Ag dot is embedded in the bridging layer and thus weaken the interface incompatibility between organic bridging layer and the next deposited metal copper layer. In the chemical plating process, a copper thickness of about 1.5 μm was achieved after 45 min’s plating. Reliability tests that the plated samples were bended by 5000 times at 5-mm and 2-mm radius, were carried out. The results showed the copper layer's resistivity was 0.5 and 0.65 times increasing respectively, in comparison with its originated property and it therefore exhibits excellent fatigue resistance.

Influence of Nb substrate morphology and atomic structure on Sn nucleation and early Nb3Sn growth

The enhanced accelerating performance of Nb3Sn-coated Nb superconducting radio frequency (SRF) cavities is severely limited by quenching sites at material defects formed during the Nb3Sn film growth procedure. In this work, we aimed to understand the complex surface-mediated interactions that drive initial Nb3Sn formation during the Sn vapor deposition procedure used to fabricate Nb3Sn coated SRF cavities. Nb substrates were modified, coated with Sn, and then characterized using an ultra-high vacuum (UHV) chamber equipped with metal deposition and in situ surface analysis capabilities. The atomic structure of the Nb oxide surface was modified to assess how the Nb surface defect density and crystallographic orientation impact the size of nucleated Sn islands and relative Nb3Sn growth rates. Formed Nb3Sn/Nb surfaces were visualized using ex situ scanning electron microscopy (SEM) and post-deposition annealing revealed Sn desorption and Nb3Sn degradation pathways. Finally, we showed that the Sn deposition conditions can be modified to overcome the growth barriers that are imposed by the Nb morphology. This study provides a unique bridge between fundamental growth studies in pristine conditions with observed phenomena of Nb3Sn grown on realistic cavity surfaces.

Wet synthesis of Cu2MnSnS4 thin films for photovoltaics: Oxidation control and CdS impact on device performances

The manganese-based quaternary chalcogenide Cu2MnSnS4 could have the chance to promote the production of sustainable solar cells, but the reported photovoltaic efficiencies are still too poor to push the research on the topic. Herein, a low-cost, straightforward, and sustainable wet methodology to synthesise Cu2MnSnS4 thin films is reported. The main issues that hindered their power conversion efficiencies have been investigated. Firstly, the manganese oxidation state has been stabilised by fine-tuning the synthesis parameters. Cu2MnSnS4 was obtained in the crystalline structure of stannite, and no oxygen was found in the material bulk. Prototype devices in substrate configuration were produced, and the new record efficiency (η = 0.92 %) for wet-synthesised Cu2MnSnS4 was reached. Since the photovoltaic performances were poor despite the high quality of Cu2MnSnS4 produced, the interface between the light absorber material and the buffer layer, CdS, was investigated, and its suitability to work as an efficient photovoltaic p-n junction was evaluated. We reveal that the buffer layer deposition procedure highly impacts the composition of the Cu2MnSnS4 surface, and that band alignment between Cu2MnSnS4 and CdS is unfavourable. The statements have been sustained by X-ray diffraction and Raman analysis, X-ray and ultraviolet photoelectron, electron paramagnetic resonance, and energy dispersive X-ray spectroscopies.

Hybrid additive manufacturing of aluminum matrix composites with improved mechanical properties compared to extruded counterparts

Great difficulties existed in fabricating large components of SiC particles reinforced aluminum matrix composites with excellent mechanical properties using existing manufacturing procedures. This study demonstrated that the challenges can be addressed by developing a hybrid solid-state additive manufacturing method. The influence of the deposition procedures and the post-processing heat treatment on the microstructure and mechanical properties of the SiC particles reinforced 2009 aluminum ally matrix composites (SiCp/2009Al composites) was systematically investigated using advanced technologies such as spherical aberration corrected transmission electron microscope, atom probe tomography, etc. The results showed that the SiCp/2009Al composites produced by the hybrid solid-state additive manufacturing exhibited enhanced tensile properties and improved isotropy in mechanical properties compared to the extruded feedstock of SiCp/2009Al composites. This was attributed to the formation of dense metal with uniformly distributed SiC particles, high-density of Cu–Mg co-clusters, refined grains and SiC particles, low deformation texture, tightly bonded SiCp/2009Al interface, and sound interfacial bonding between deposited layers.

Crack-free hard facing options for orifice plate used in oil refinery applications

The purpose of this study is to select a suitable tubular wire electrode as an alternative hardfacing material for Stellite 1 in the production of SS304 orifice plates used in oil refineries. It is also intended to develop an efficient deposition procedure for crack-free hardfacing. Compatible cobalt, nickel, and iron-based hardfacing alloys were selected so as to match the hardness and hot hardness properties of stellite 1. Moving heat source analysis was performed to find the heat affected zones and the thermal stress distribution during hardfacing. The significance of weld speed, bead width, and weld concentration on the weld deposition process was analysed using ANSYS, to extract an efficient deposition procedure. The hardfacing alloys were tested for stress and deformation at working temperature (up to 815 οC) to understand the performance. Seven materials were taken into consideration as options along with six parameters. The results revealed a higher longitudinal residual stress of 2000 MPa for Talonite and Tribaloy hardfacing alloys. Colmonoy 6 was found to be having the least stress value of 2186 MPa. Furthermore, the von mises stress values arrived for different conditions showed that the optimal welding condition is 5 mm/s welding speed, 3 mm radius of beam and 455 °C preheat temperature. Microstructural study revealed the dendrite growth in the surface of Colomony 6 hardfacing during solidification, which led to the improvement in mechanical properties.

A study on the fabrication procedure for a high-D/Ti-ratio-deuterated-titanium film on the disk-type neutron generator target

This study aims to present thin film deposition and deuterium adsorption procedure to fabricate disk-type targets with high D/Ti values for a neutron generator and increase their lifespan. The neutron target consists of a titanium thin film with hydrogen loading, and a copper substrate for heat removal. We optimized the incident deuterium ion beam energy and thin film thickness using Geant4 simulations. Additionally, we calculated the expected neutron yield under the optimized conditions. The hydrogen adsorption conditions were optimized by comparing the H/Ti results as per hydrogen adsorption temperature and loading time using titanium foils of different thickness values. Hydrogen (or deuterium) adsorption ratio is strongly influenced by the surface condition and the deposition conditions of the thin film. A titanium film was deposited in various conditions of plasma DC power and substrate temperature. The quality of the thin film was evaluated through surface roughness evaluation and thin film sheet resistance for each deposition conditions. Subsequently, the hydrogen adsorption results were compared according to the quality of the thin titanium films, and the thin titanium film deposition conditions with the highest hydrogen adsorption ratio were confirmed. The selected conditions were applied to conduct deuterium adsorption. In conclusion, this study underscores the critical relationship between thin film quality and hydrogen (or deuterium) adsorption ratio, reinforcing the importance of optimizing thin film deposition parameters for the design of neutron generator disk-type targets with high quality of film and extended lifespan.

Realization of either physisorption or chemisorption of 2H-tetraphenylporphyrin on the Cu(111) from density functional theory

The adsorption of organic molecules to surfaces is a central issue to achieve fully-functional molecular devices, for which porphyrins are well-studied due to their chemical stability and functional diversity. Herein, we investigate both the physical and the chemical adsorption of the free-base tetraphenylporphyrin 2H-TPP on the Cu(111) surface within the framework of density functional theory and find that the most stable physisorbed configuration is more weakly bound by −0.31 eV than the chemisorbed configuration. We use the electron localization function to investigate the difference in binding mechanisms between strong physisorption and weak chemisorption. We have computed a reaction barrier of 0.12 eV in going from physical binding to chemical bonding to the surface, and a barrier of 50 meV in going between neighboring physical binding sites. Our results support the possibility of realizing free-base porphyrins either physisorbed or chemisorbed on Cu(111) depending on the deposition procedure and experimental conditions.

An Integrated Deposition and Passivation Strategy for Controlled Crystallization of 2D/3D Halide Perovskite Films.

This work introduces a simplified deposition procedure for multidimensional (2D/3D) perovskite thin films, integrating a phenethylammonium chloride (PEACl)-treatment into the antisolvent step when forming the 3D perovskite. This simultaneous deposition and passivation strategy reduces the number of synthesis steps while simultaneously stabilizing the halide perovskite film and improving the photovoltaic performance of resulting solar cell devices to 20.8%. Using a combination of multimodal in situ and additional ex situ characterizations, it is demonstrated that the introduction of PEACl during the perovskite film formation slows down the crystal growth process, which leads to a larger average grain size and narrower grain size distribution, thus reducing carrier recombination at grain boundaries and improving the device's performance and stability. The data suggests that during annealing of the wet film, the PEACl diffuses to the surface of the film, forming hydrophobic (quasi-)2D structures that protect the bulk of the perovskite film from humidity-induced degradation.

Correlation of Fabrication Methods and Enhanced Wear Performance in Nanoporous Anodic Aluminum Oxide with Incorporated Molybdenum Disulfide (MoS2) Nanomaterials.

Wear performance is integral to component longevity, minimizing industrial waste and excess energy costs in a wide variety of applications. Anodized aluminum oxide (AAO) has many beneficial properties leading to its wide use across industries as a surface treatment for many aluminum components, but the wear properties of the coating could be improved significantly. Here, we used an electrochemical method to incorporate molybdenum disulfide (MoS2), a nanomaterial used as a dry lubricant, to modify alloys of aluminum during AAO preparation. Using Raman spectroscopy and tribological scratch measurements, we thoroughly characterized the structure and wear behavior of the films. The MoS2 deposition procedure was optimal on aluminum 5052 anodized in higher acid concentrations, with friction coefficients at around 0.05 (~10× better than unmodified AAO). Changing anodization conditions to produce harder films with smaller pores led to worsened wear properties, likely because of lower MoS2 content. Studying a commercial MoS2/AAO film of a different Al alloy (7075) showed that a heat treatment step intended to fully convert all deposited MoSx species to MoS2 can adversely affect wear in some alloys. While Al 6061 and 1100 produced films with worse wear performance compared to Al 5052 or 7075, our results show evidence that acid cleaning after initial anodization likely removes residual alloying elements, affecting MoS2 incorporation. This study demonstrates a nanomaterial modified AAO film with superior wear characteristics to unmodified AAO and relates fabrication procedure, film structure, and practical performance.

Amino Acid Polymerization on Silica Surfaces.

The polymerization of unactivated amino acids (AAs) is an important topic because of its applications in various fields including industrial medicinal chemistry and prebiotic chemistry. Silica as a promoter for this reaction, is of great interest owing to its large abundance and low cost. The amide/peptide bond synthesis on silica has been largely demonstrated but suffers from a lack of knowledge regarding its reaction mechanism, the key parameters, and surface features that influence AA adsorption and reactivity, the selectivity of the reaction product, the role of water in the reaction, etc. The present review addresses these problems by summarizing experimental and modeling results from the literature and attempts to rationalize some apparent divergences in published results. After briefly presenting the main types of silica surface sites and other relevant macroscopic features, we discuss the different deposition procedures of AAs, whose importance is often neglected. We address the possible AA adsorption mechanisms including covalent grafting and H-bonding and show that they are highly dependent on silanol types and density. We then consider how the adsorption mechanisms determine the occurrence and outcome of AA condensation (formation of cyclic dimers or of long linear chains), and outline some recent results that suggest significant polymerization selectivity in systems containing several AAs, as well as the formation of specific elements of secondary structure in the growing polypeptide chains.

Fabrication of Si Anode for Enhancing Electrochemical Performance by Electrodeposition Method

Silicon (Si) is one of the most abundant elements in the earth's crust and is important for the development of semiconductors, solar cells, and lithium ion battery (LIB)electrodes. silicon nanomaterials-based device production is currently hampered by high prices, high material consumption, and very sophisticated procedures of film deposition, including chemical vapour deposition (CVD) and plasma-enhanced chemical vapour deposition (PE-CVD).Future demand will need the development of cost-effective, simple, and high-throughput deposition techniques.moreover A large-scale use of Si anodes in LIB is hindered primarily by two factors: (a) a significant volume change (about 300%) during discharging and (b) the deterioration of silicon after several charging and discharging cycles. By covering silicon nanostructures with carbon nanomaterials that also improve the electrochemical performance of LIBs, these disadvantages may be eliminated. In order to meet all of these requirements, the electrodeposition approach may provide the means to create Si thin films in an aesthetic way. We studied We used water-contaminated BMImTf2N to electrolyze SiNPs on Graphene (Grn) -coated copper substrates at room temperature.SiNPs average 70-90 nanometres (nm). Grn layer on the Cu substrate enhances Si nucleation and prevents oxidation. At 0.5C, the charge capacity was 1350 mAh g-1 and the discharge capacity was 1588 mAh g-1. The columbic process's efficiency increased from 85% to 97% after 100 cycles. Grn's conductivity and volume expansion will boost Si's cycle life. Figure 1

Solution ALD Processing of Halide Perovskite Thin Films Yields Superior Functional Quality and Stability Than Classical Processing

The range of materials accessible by classical ALD is limited by the volatility requirement applied to the precursors. However, solution ALD (sALD) transfers the self-limiting surface reaction principle of ALD into the solution processing realm and allows for the same level of control in the deposition of ionic or molecular solids, such as polymers, metal-organic frameworks, and halide perovskites, which cannot be delivered from the gas phase.We have developed an sALD procedure for the direct deposition of the prototypical halide perovskite compound, methylammonium triiodoplumbate(IV), (H3CNH3)(PbI3), also referred to as methylammonium lead iodide or MAPI. The process saturates upon dosage variation to a self-limiting growth rate. The material is obtained in crystalline and highly pure, stoichiometric form at room temperature. All analytical techniques confer to indicate the absence of any lead iodide trace. The MAPI layers generated by sALD can be integrated into planar heterojunction stacks and yield functional solar cells.The direct comparison of films of several thickness values prepared in pairs by sALD and by a state-of-the-art spin-coating method shows that the sALD films always overperform their spin-coated counterparts both in terms of charge carrier lifetimes and in terms of stability towards decomposition under thermal, radiative or vacuum stress.Thus, experimental atomic-level control of solution-processed semiconductors is accessible for the first time. It can now be applied to the accurate investigation of halide perovskite photophysics and photochemistry fundamentals as they pertain to transport and interface phenomena.

CO2 methanation over open cell foams prepared via chemical conversion coating

In the framework of the CO2 utilization, and of the integration of renewable energy sources into the power generation scenario, the methanation reaction plays a key role, being the core of the power-to-gas, or power-to-X, processes. Structured catalysts are widely recognized for being particularly promising in exothermic processes, as they ensure a better thermal management of the heat generated within the system. In recent years, the application of metallic structures has spread. Nevertheless, the functionalization of these structures via washcoating procedure has several disadvantages. Herein, it is highlighted the potential of ceria chemical-conversion coating (CCC) as technique for the preparation of methanation catalysts, and optimize the Ni deposition procedure on such structures. In this work, the suitability of the obtained catalysts for CO2 methanation was evaluated in several operating conditions, obtaining CO2 conversion as high as 70 % below 400 °C with the most promising sample. In a first analysis, it was demonstrated that the catalysts prepared through the CCC technique can be applied in the CO2 methanation systems. In addition, through a kinetic analysis it was highlighted that the preparation method could be a key parameter for the selectivity of the process, driving the system towards a direct CO2 methanation or to the CO-path mechanism, therefore further studies should be performed to better explore this aspect.