Slow Deposition Rate Research Articles

Two stages of subsidence and its formation mechanisms in Mid-Late Triassic Ordos Basin, NW China

Based on a large number of newly added deep well data in recent years, the subsidence of the Ordos Basin in the Mid-Late Triassic is systematically studied, and it is proposed that the Ordos Basin experienced two important subsidence events during this depositional period. Through contrastive analysis of the two stages of tectonic subsidence, including stratigraphic characteristics, lithology combination, location of catchment area and sedimentary evolution, it is proposed that both of them are responses to the Indosinian Qinling tectonic activity on the edge of the craton basin. The early subsidence occurred in the Chang 10 Member was featured by high amplitude, large debris supply and fast deposition rate, with coarse debris filling and rapid subsidence accompanied by rapid accumulation, resulting in strata thickness increasing from northeast to southwest in wedge-shape. The subsidence center was located in Huanxian–Zhenyuan–Qingyang–Zhengning areas of southwestern basin with the strata thickness of 800–1 300 m. The subsidence center deviating from the depocenter developed multiple catchment areas, until then, unified lake basin has not been formed yet. Under the combined action of subsidence and Carnian heavy rainfall event during the deposition period of Chang 7 Member, a large deep-water depression was formed with slow deposition rate, and the subsidence center coincided with the depocenter basically in the Mahuangshan–Huachi–Huangling areas. The deep-water sediments were 120–320 m thick in the subsidence center, characterized by fine grain. There are differences in the mechanism between the two stages of subsidence. The early one was the response to the northward subduction of the MianLüe Ocean and intense depression under compression in Qinling during Mid-Triassic. The later subsidence is controlled by the weak extensional tectonic environment of the post-collision stage during Late Triassic.

Superhydrophilic conformal polydopamine coating on nanostructured surface formed by capillary-induced solution infusion

As a material-independent adhesive coating agent with excellent functionality on interfaces of materials, polydopamine (PDA) has been widely applicable in bioengineering, environment, and energy fields. Conventional coating methods using dopamine (DA) solutions suffer from slow deposition rates, hindering the attainment of adequate thickness and durability. This work introduces a technique involving rapid capillary-induced solution infusion and in-air polymerization to overcome these limitations. By immersing nanostructured surfaces for just 10 s into the solution, the DA solution is uniformly infused onto the surface, and distributed evenly over the nanostructured surfaces. Polymerization is facilitated by oxygen diffusion from the air, resulting in the formation of a conformal coating up to a micrometer thick. These PDA coatings exhibit persistent superhydrophilicity with water contact angle below 10° and maintain resistance to abrasion, sonication, and oil fouling. Additionally, when applied to microfiber textiles, the PDA coating leads to excellent underwater oil repellency. Our method holds promise for compatibility with various wet-based coating techniques such as drop casting, spraying, spin coating, or ink-jet printing, opening avenues for versatile applications in diverse fields.

In Development: 3D printed large Format composite tooling using a Robot-Mounted pellet extruder

Large Format Additive Manufacturing (LFAM) addresses the limitations of traditional 3D printing, including slow deposition rates, limited scalability, lengthy prints, and high tooling costs for large structures. Current LFAM relies on quasi-planar, 2.5D printing strategies. This fails to reap the advantages of multi-axis printing, such as reduced support material use and the ability to create complex curved surfaces. A pellet-fed, multi-axis, large-format 3D printer was developed, featuring a KUKA robot and linear rail to enable multi-axis capabilities. LFAM’s potential is demonstrated by designing and simulating the printing process for a mold of a composite wing with a winglet.

High-density stable glasses formed on soft substrates.

Enabled by surface-mediated equilibration, physical vapour deposition can create high-density stable glasses comparable with liquid-quenched glasses aged for millions of years. Deposition is often performed at various rates and temperatures on rigid substrates to control the glass properties. Here we demonstrate that on soft, rubbery substrates, surface-mediated equilibration is enhanced up to 170 nm away from the interface, forming stable glasses with densities up to 2.5% higher than liquid-quenched glasses within 2.5 h of deposition. Gaining similar properties on rigid substrates would require 10 million times slower deposition, taking ~3,000 years. Controlling the modulus of the rubbery substrate provides control over the glass structure and density at constant deposition conditions. These results underscore the significance of substrate elasticity in manipulating the properties of the mobile surface layer and thus the glass structure and properties, allowing access to deeper states of the energy landscape without prohibitively slow deposition rates.

Sedimentological and ichnological variations in fluvio‐tidal translating point bars, McMurray Formation, Alberta, Canada

ABSTRACTSedimentological and ichnological descriptions of fluvio‐tidal translating point bars are rare, and complex physico‐chemical processes make highly detailed but concise facies descriptions challenging. Herein, mesofacies are defined to describe and interpret three ancient translating point bars from the Lower Cretaceous McMurray Formation, Alberta, Canada. Twenty‐three mesofacies are defined, based on their recurring sedimentological and ichnological characteristics. These mesofacies form the building blocks of beds and bedsets that make up three depositional facies. Facies 1 reflects sand dune migration at the channel base, which grades into inclined heterolithic stratification of Facies 2 and 3. Facies 2 occurs in the centre and seaward portions of the translating point bars and records tide‐dominated deposition of sand and muddy sand during periods of reduced river discharge. Ichnological suites and bioturbation intensities in these beds reflect persistent but variable brackish‐water conditions, fluctuating deposition rates and the deposition of mud. Mud beds are derived from flows with high suspended‐sediment concentrations. Tidally derived mud beds are typically bioturbated with trace fossil suites indicative of slow deposition rates and brackish‐water conditions. Mud deposited during elevated river discharge is burrowed after the dewatering of the bed. Facies 3 occurs at the landward apex of the translating point bar and is marked by sand‐rich and mud‐rich dune deposits with abundant soft‐sediment deformation, indicative of elevated flow velocities and deposition rates. Bioturbation is rare and sporadically distributed owing to unstable substrates. The distribution of the facies reflect the hydrodynamic variations that occurred vertically and laterally across the bar in response to temporal variations in fluvial and tidal flow interaction, as recorded by their mesofacies. The detailed facies analysis strongly suggests that deposition of the three McMurray Formation translating point bars occurred in proximity to the turbidity maximum zone of a fluvio‐tidal channel system.

Insights to the production of SnS-cubic thin films by vacuum thermal evaporation for photovoltaics

Thin films of SnS-CUB with a lattice constant of 11.6 Å, 32 units of SnS per cell and an optical bandgap (E g) of 1.7 eV (direct), are mostly produced by chemical techniques. This cubic polymorph is distinct from its orthorhombic polymorph (SnS-ORT) with an E g of 1.1 eV. This work is on the deposition of SnS-CUB thin films of 100–300 nm in thickness by thermal evaporation at substrate temperatures of 400 °C–475 °C on glass or on a chemically deposited SnS-CUB thin film (100 nm). Under a slow deposition rate (3 nm min−1) from a SnS powder source at 900 °C, the thin film formed on a SnS-CUB film or glass substrate at 450 °C is SnS-CUB. At a substrate temperatures of 200 °C–350 °C, the thin film is of SnS-ORT. A low atomic flux and a higher substrate temperature favor the growth of SnS-CUB thin film. The E g of the SnS-CUB film is nearly 1.7 eV (direct gap), and that of the SnS-CUB film is 1.2 eV (indirect gap). The electrical conductivity (σ) of SnS-CUB and SnS-ORT films are 10–7 and 0.01 Ω–1 cm−1, respectively. A proof-of-concept solar cell of the SnS-CUB thin film showed an open circuit voltage of 0.478 V, compared with 0.283 V for the SnS-ORT solar cell. The insights to the deposition of SnS-CUB and SnS0.45Se0.55-CUB (E g, 1.57 eV; σ, 0.02 Ω−1 cm−1) thin films by vacuum thermal evaporation offer new outlook for their applications.

Hydrocarbon generation potential and organic matter accumulation patterns in organic-rich shale during the mesoproterozoic oxygenation event: evidence from the Xiamaling formation shale

A significant deposition of black shales occurred during the Mesoproterozoic Oxygenation Event (MOE). In order to investigate the hydrocarbon generation potential and organic matter enrichment mechanism of these shale deposits, we studied the Xiamaling Formation shale in the North China region as a representative sample of the Mesoproterozoic shale. The research involved organic petrology, organic geochemistry, mineralogy, and elemental geochemistry. The following observations were made: (1) The depositional environment of the Xiamaling Formation shale can be categorized as either oxic or anoxic, with the former having shallow depositional waters and high deposition rates, while the latter has deeper depositional waters and slower deposition rates. (2) Anoxic shales exhibited significantly better hydrocarbon generation potential compared to shales deposited in oxic environments, although the latter still demonstrated high hydrocarbon generation potential. (3) Shales deposited in anoxic environments displayed higher paleoproductivity compared to those deposited in oxic environments. The high deposition rate in oxic environments slowed the decomposition and mineralization of organic matter, leading to the formation of high-quality shales. In contrast, the strong paleoproductivity, along with favorable preservation conditions, accounted for the high hydrocarbon potential of anoxic shales.

Additive Manufacturing of Inductors and Transformers by Hybrid Aerosol Jet Printing and Electrochemical Deposition

Aerosol jet printing (AJP) is an attractive additive manufacturing process for printed electronic applications due to its high resolution (< 10 µm), flexible stand-off distance, and support of both metal and dielectric materials. A slow deposition rate (< 1 µm per layer) and the relatively low conductivity achievable with commercially available nanoparticle inks (~40% bulk) present some of the current limitations associated with AJP. Electrochemical deposition methods including both electrodeposition and electroless deposition are widely used in the microelectronics industry. Dense, high conductivity layers several 10s of µm can be deposited with well-established plating processes. Metals including Cu and Ni which are challenging to deposit by AJP, can be easily/readily deposited using commercially available plating baths. A hybrid approach of seed layer deposition using AJP and electrochemical deposition of highly conductive copper is used to improve the overall conductance of the printed structures. [1] Here, we apply this combined approach to the manufacturing of transformer and inductor devices.We have successfully prepared a two-layer secondary inductor on top of a two-layer primary inductor to form a coreless flyback transformer (Figure 1(a)). These inductors were fabricated by AJP of an Ag seed layer, followed by electroless deposition and electrodeposition of Cu and Ni. UV-curable dielectric polymer layers were deposited by AJP to separate each inductor layer. The flyback transformer produced a gain of 75.3x with an input voltage of 17 V at 400 kHz resulting in an output voltage of 1250 V (Figure 1(b)). We also demonstrated the repeated stacking of 8 coil layers by AJP of Ag seed layers and electrodeposition of Cu and Ni (Figure 1(c)). These inductors had an average equivalent series resistance of 0.6 Ω and a 1.7 µH inductance at 100 kHz (Figure 1(d)). Finally, we will study the deposition of these inductor and transformer devices on magnetic substrates, characterizing changes in inductance and gain. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. SAND2022-17001 A

Thin Films Fabricated by Pulsed Laser Deposition for Electrocatalysis

Thin Films Fabricated by Pulsed Laser Deposition for Electrocatalysis

Continuous ink supply and circulation system for a multi-nozzle electrospray

The electrospray deposition method has been used in many applications, such as mass spectroscopy, thin film deposition, bio-applications, painting and coating. However, low flow rates must be used for electrospraying to maintain a stable cone jet mode, while most applications require high throughput. To overcome the slow deposition rate, the use of a multi-nozzle electrospray should be considered. In a typical multi-nozzle electrospray system, ink in a syringe barrel is fed to the nozzles by a syringe pump or pressure regulator. However, if the ink in the syringe barrel is depleted, the entire process should be stopped to refill the ink. In this study, we propose a new head design and an ink supply system for a multi-nozzle electrospray system so that ink can be continuously supplied to the nozzles without ink being depleted during the electrospray process. The proposed system is based on circulation through the multi-nozzle electrospray head so that unexpected air bubbles in the head can be easily removed.

Rapid co-deposition of dopamine and polyethyleneimine triggered by CuSO4/H2O2 oxidation to fabricate nanofiltration membranes with high selectivity and antifouling ability

Membrane surface properties play important roles in the separation performance and fouling behavior during the membrane-based water treatment processes. Mussel-inspired polydopamine (PDA) layer with abundant functional groups can endow the membrane surface with increased hydrophilicity as well as extraordinary versatility and creative potential for further functionalization toward specific applications. However, the slow deposition rate still limits its application in membrane modification. In this study, rapid deposition of the PDA layer on the surface of the polysulfone membrane was realized by catalytic oxidation using CuSO4/H2O2. Meanwhile, polyethyleneimine (PEI) was introduced to co-deposit with PDA to obtain a hydrophilic, uniform, and electroneutral separation layer for the nanofiltration membrane. An optimized stoichiometry of modifiers and oxidants was obtained by UV–vis absorbance measurement. The membrane surface properties including surface morphology, roughness, chemical element compositions, wettability, and charge behavior before and after modification were characterized through various techniques. The optimized PDA/PEI modified membrane (a-Cu(15)-PDA/PEI) possessed higher MgCl2/NaCl and dye/salt selectivities as well as improved anti-fouling performance compared to the commercial NF-270 membrane. Furthermore, the Gaussian simulation combined with XPS analysis illustrated that the introduction of Cu2+/H2O2 accelerated the dopamine oxidation and facilitated the formation of CO quinoid structures, thus providing more reactive sites for the Schiff base reaction in the PDA/PEI co-deposition process. The results from this study provide theoretical foundations for improving nanofiltration membrane performances by PDA/PEI modification.

LiCoO2 Battery Electrode Fabricated by High Deposition-Rate Atmospheric Plasma Spraying for Lithium Battery

Lithium cobalt oxide (LiCoO2, LCO) thin-film cathodes are usually prepared with slow deposition rates by sputtering techniques. Atmospheric plasma spraying (APS) is a possible technology for the rapid deposition method replacing sputter deposition to fabricate all-solid-state lithium batteries. This study employed the APS device to rapidly deposit LCO thick films as cathodes with deposition rates exceeding 5,400 nm min−1. The results show that the LCO cathodes have presented a specific capacity of 120 mAh g−1 after being annealed and assembled in a gel polymer electrolyte lithium battery. Furthermore, the LCO cathodes also demonstrated a high areal capacity of 5.65 mAh cm−2, one of the best areal capacity performances. Therefore, APS technology offers a highly competitive approach to commercializing energy storage products.

In-situ aeration-assisted polydopamine/polyethyleneimine copolymerization and deposition for rapid and uniform membrane modification

The key to membrane separation technology is to enhance membrane selectivity while ensuring high permeability. The modification of polydopamine (PDA) deposition based on mussel bionics is an important method to prepare hydrophilic membranes, in which the slow PDA deposition rate and nonuniformity are the keys to the strategy. In this work, a novel in-situ aeration-assisted PDA/PEI copolymerization and deposition method was designed. The influence of the in-situ aeration-assisted method on the structure and properties of the modified membranes was explored. The results indicated that the dissolved oxygen content and uniformity of the solution were improved, and the copolymerization and deposition rate of PDA/PEI were obviously accelerated. Hydrophilic coating could be formed on the PTFE membrane surface in a shorter time. The hydrophilicity and pore size uniformity were promoted, and approximately 19.4 times flux (from 101.7 L/(m2·h) to 1969.7 L/(m2·h)), 44% rejection to BSA and 60% FRR increase were obtained simultaneously. The stability of the compound coating and the possibility of the method on different substrate membranes were testified. The work could provide more insight for PDA/PEI reaction regulation and membrane modification.

Low-temperature hydrogen sensor based on sputtered tin dioxide nanostructures through slow deposition rate

In this paper, tin dioxide (SnO2) mesoporous nanostructures (pores of 2 and 50 nm) were directly sputtered on a Pt-interdigitated electrode (gap length of 35 μm) with a slow deposition rate of 5 nm/min under a controlled substrate temperature of 100, 350, and 500 °C. It is found that the surface area was 0.22 × 104, 0.18 × 104, and 0.17 × 104 observed for the nanostructure prepared at 350 °C, 500 °C, and 100 °C, respectively. The film crystallinity increased with increasing the substrate temperature. The film prepared at 500 °C showed a lower resistivity in air. Most importantly, the sensor fabricated by using the nanostructure prepared at 500 °C exhibits excellent low-temperature (100 °C) H2 sensing properties. When this sensor is exposed to 1000 ppm (0.1%) H2, the sensor response is 30 × 103 %. The sensing performances are superior to those of most reported at higher temperature H2 sensors based on SnO2 materials. Interesting is the sensor selectivity, where the sensor prepared at 500 °C is selective toward H2 gas, while the sensor prepared at 350 °C is selective toward NO2 gas. The sensing performance of the sensor prepared at 500 °C for H2 (reducing gas) was attributed to a proposed mechanism of a coulomb interaction (electric dipole). The sensors exhibit two different behaviors of their electrical resistivities upon exposure to H2 gas at low and high temperatures. The gas sensing mechanisms for such behaviors were proposed to understand the sensor behavior. The current results may assist in realizing high selective sensors toward H2 for the commercial market.

Structural tunability and origin of two-level systems in amorphous silicon

Amorphous silicon films prepared by electron beam evaporation have systematically and substantially greater atomic density for higher thickness, higher growth temperature, and slower deposition rate, reaching the density of crystalline Si when films of thickness greater than ~300 nm are grown at 425 $^{\circ}$C and at <1 $\r{A}$/sec. A combination of spectroscopic techniques provide insight into atomic disorder, local strains, dangling bonds, and nanovoids. Electron diffraction shows that the short-range order of the amorphous silicon is similar at all growth temperatures, but fluctuation electron microscopy shows that films grown above room-temperature show a form of medium-range order not previously observed in amorphous silicon. Atomic disorder and local strain obtained from Raman spectroscopy reduce with increasing growth temperature and show a non-monotonic dependence on thickness. Dangling bond density decreases with increasing growth temperature and is only mildly dependent on thickness. Positron annihilation Doppler broadening spectroscopy and electron energy loss spectroscopy show that nanovoids, and not density variations within the network, are responsible for reduced atomic density. Specific heat and mechanical loss measurements, which quantify the density of tunneling two-level systems, in combination with the structural data, suggest that two-level systems in amorphous silicon films are associated with nanovoids and their surroundings; which are in essence loosely bonded regions where atoms are less constrained.

Probing the formation of ultrastable metallic glass from structural heterogeneity

• The structure underlying the unexpected stability of Zr-based TFMGs was tracked. • MGs with greater heterogeneity have a higher potential to form SMGs. • Slower deposition rates are required for ultrastability in more heterogeneous MGs. • The relaxation mechanism changes as the deposition rate decreases. • The geometry and distribution of loosely packed phases determines ultrastability. Ultrastable metallic glasses (SMGs) exhibit enhanced stability comparable to those of conventional glasses aged for thousands of years. The ability to understand why certain alloy compositions and processing conditions generate an SMG is an emerging challenge. Herein, amplitude-modulation dynamic atomic force microscopy was utilized for tracking the structure of Zr 50 Cu 50 , Zr 50 Cu 44.5 Al 5.5 and Zr 50 Cu 41.5 Al 5.5 Mo 3 thin film metallic glasses (TFMGs) that were produced by direct current magnetron sputtering at room temperature with the rate of deposition being the only variable. The transition in stability from bulk- to SMG-like behavior resides in the change of relaxation mechanism as the deposition rate is decreased. The formation of SMGs is directly linked with the degree of structural heterogeneity, whereby MGs with greater heterogeneity have a higher potential to form SMGs with more significant enhancement in stability. Slower deposition rates, however, are required to yield the more homogenous structure and lower energy state underlying the ultrastability. Ultrastability is closely linked with the geometric shape and distribution of loosely packed phases, whereby SMGs containing more slender loosely packed phases with a more skewed distribution achieve more significant improvements in stability. This work not only provides direct evidence of the structure of SMGs, but also opens new horizons for the design of SMGs. .

A Green and Cost-Effective Synthesis of Hierarchical SAPO-34 through Dry Gel Conversion and Its Performance in a Methanol-to-Olefin Reaction

In this work, a low-cost and high-performance methanol-to-olefin (MTO) catalyst was synthesized by dry gel conversion (DGC). Using tetraethylammonium hydroxide (TEAOH) as the structure-directing agent (SDA) to prepare the dry gel, nano-SAPO-34 in a range of 50–500 nm was synthesized under the effect of the vapor of triethylamine (TEA) and H2O. The TEAOH consumption using this method was only 7.5% of that in the hydrothermal synthesis (HTS), and the yield of nano-SAPO-34 products was up to 94%. When scaling up to the pilot test, obvious heterocrystals appeared with the decrease in SiO2 content in the dry gel. Our results showed that the heterocrystals were completely eliminated after the introduction of fluoride into the dry gel. A low acid density nanosheet-SAPO-34 molecular sieve product with good micropore, mesopore, and macropore connectivity was obtained. The obtained multikilogram-scale molecular sieve sample can be directly shaped to obtain MTO microsphere catalysts by spray drying without separation and washing. No wastewater was produced during the whole process, demonstrating an entirely green production way. The MTO performance of the microsphere catalysts was tested in a fluidized bed reactor, and results showed that the catalysts exhibited the characteristics of a slow carbon deposition rate and a high activity utilization ratio. Their lifetime was extended by 14%, and their selectivity (C2= + C3=) was increased by 1.55%, so they are very suitable for industrial application. This work has provided the theoretical and practical basis for the industrial production and application of DGC in the future.

Parametric Study of Automated Electrospark Deposition for Ni-Based Superalloys

Conventional electrospark deposition (ESD) processes used in industry are well suited to the coating and repair of small areas for the purpose of hardfacing, corrosion resistance, or dimensional restoration. Although significant advances have been made in the range of materials that can be processed, the comparatively slow deposition rate limits the potential applications of a traditional manually operated ESD process. In this study, an automated ESD system was demonstrated for the application of Ni-based superalloy (Inconel 718) coatings on Ni- and Fe-based substrates. A preliminary study was used to determine the influence of process parameters on an automated system, with capacitance, voltage, electrode force, and electrode travel speed parameters chosen to provide higher deposition rates while maintaining high deposition quality. A comparison of Inconel 718 and 316L stainless steel substrates found that the influence of substrate composition on coating hardness and coating composition was limited to the first 40um. These results pave the way for ESD of larger-area coatings and longer-duration repairs without the need for human operators.

Advective sorting of silt by currents: A laboratory study

AbstractAccumulations of fine sediments along continental shelf and deep‐sea bathymetric contours, known as contourite drifts, form a sedimentary record that is dependent on oceanographic processes such as ocean–basin‐scale circulation. A tool used to aid in interpretation of such deposits is the sortable silt hypothesis, which suggests that the mean size of the sortable silt (silt from 10 to 63 μm) within a deposit can be used as a proxy for current velocity. While the hypothesis has been applied to numerous drift deposits, it has not been extensively explored. Slow deposition rates of contourite drift systems make it difficult to study in the deep ocean, and past laboratory studies have not tested the full range of conditions or mechanisms that could lead to sorting. This study uses flume experiments and theory to examine how the mean sortable silt in a deposit is related to current velocity under the action of advective depositional sorting. Tests were conducted for a fixed amount of time with four suspended sediment mixtures and current velocities typical of deep‐sea settings (5 to 25 cm s−1). Developed beds were sampled at fixed locations from the entrance and sized. The deposit grain size fined downstream and coarsened with increasing velocity at a particular distance from the inlet. Simple theory was able to capture the observations. Regardless of bed morphology or source sediment mixture, the mean sortable silt in the deposit was related to velocity at a particular flume location across all sediment mixtures. The slope of the relationship between velocity and size was dependent on the distance between the inlet and location of interest. Despite the simplified nature of the study, and the limitations regarding the presumed variability in natural systems, these findings broadly support the validity of mean sortable as a proxy for palaeocurrent velocity at a distance along a depositing current.

Aggregation and Deposition Kinetics of Polystyrene Microplastics and Nanoplastics in Aquatic Environment.

Microplastics (MPs) and nanoplastics (NPs) attract widespread attention due to their final threats to human health. Here, 50 nm and 500 nm polystyrene particles (PS50 and PS500) were selected as the typical NPs and MPs, respectively. Their aggregation kinetics was monitored, and their deposition was investigated on silica and alumina surfaces using quartz crystal microbalance with dissipation monitoring (QCM-D). PS500 has higher critical coagulation concentration (CCC) values than PS50, because of the weaker Brownian diffusion, less particle number and lower collision chance. PS50 has smaller values of critical deposition concentration (CDC) than PS500, indicating the stronger adsorption on silica. Derjaguin-Landau-Verwey-Overbeek (DLVO) calculations explain that PS500 has weaker attachment on silica and slower deposition rate on alumina than PS50. Our results demonstrate that solution chemistry, particle size and mineral surfaces determine the transport and distribution of plastic particles together.