Effect Of Deposition Process Research Articles

Improved tribological and electrochemical behavior of concentrated chromite coatings developed by HVOF and plasma spray techniques

Mineral coatings have the ability to tackle the most common degradation processes (wear and corrosion) in industries at amazing ‘quality to cost’ ratio, as compared to synthetic ceramics. In the current study, concentrated natural chromite with 55 wt.% Chromium oxide (Cr2O3) is deposited on steel substrate through High Velocity Oxygen Fuel (HVOF) and Atmospheric plasma spray (APS) techniques. Effect of deposition processes and Cr2O3 enrichment on microstructure, hardness, tribological and electrochemical behavior of coatings is studied. Tribological tests were performed using pin-on-disc setup, coatings deposited with APS have shown excellent wear resistance behavior as compared to HVOF coating. Owing to the brittle nature of chromite coatings, they were worn by abrasive wear irrespective of the deposition process. Electrochemical behavior of coatings is evaluated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. APS and HVOF coatings have exhibited very high protective efficiency of 93 and 88% respectively, against steel substrate. Equivalent electrical circuit (EEC) based on EIS results has also been conceptualized and verified with ZSimpWin analysis software. Established EEC has illustrated capacitive behavior due to the protective oxide nature of coatings. Despite having relatively higher porosities in APS coatings, they display an excellent potential for wear and corrosion resistant applications. Results revealed that hardness, compactness, tribological and corrosion performance of chromite coatings have been substantially improved due to higher Cr2O3 content.

Ab initio supported study on the selective adsorption-induced microstructural difference of (Ti,Al)N/TiN and (Ti,Al)N/ZrN multilayers

Interface structure is essential for the mechanical properties of multilayers. Here, the effect of deposition process on the interface structure of arc-evaporated (Ti,Al)N/TiN and (Ti,Al)N/ZrN multilayers is studied by a combination of ab initio calculations and experiments. Based on x-ray diffractions and transmission electron microscope investigations, both multilayers with close modulation ratio and period reveal face centered cubic (fcc) structure with coherent interfaces. Nevertheless, thin (Ti,Zr)N layers are formed near the interfaces in (Ti,Al)N/ZrN multilayer, but are absent in (Ti,Al)N/TiN multilayer. Ab initio calculations suggest the selective absorption of Ti and Zr adatoms onto the surface of (Ti,Al)N/ZrN multilayer during deposition, which leads to the formation of (Ti,Zr)N-rich layers by interface. However, (Ti,Al)N/TiN multilayer is predicted to have almost constant surface adsorption of different adatoms.

Effect of the Deposition Process on High-Temperature Microstructure and Properties of the Direct Energy Deposition Al-Cu Alloy

The excellent microstructure and mechanical properties of Al-Cu alloy deposited using the Direct Energy Deposition (DED) process has been shown in previous studies, which is the most likely aluminum alloy material to meet the load-bearing requirements of hypersonic aircraft. However, its high-temperature performance and the law of microstructure transformation during the high-temperature process still need to be determined. In this paper, DED Al-Cu alloy samples were prepared using the Cold Metal Transfer (CMT) process, CMT Pulse process, and CMT Pulse Advanced process. The effect of different deposition processes on the microstructure and mechanical properties of the deposits was investigated at 200 °C for 30 min. The results show that the Al-Cu alloy’s main strengthening phase θ′ is excessively transformed into the equilibrium θ phase after the high-temperature process, which is the main reason for the degradation in the DED Al-Cu alloy’s properties at high temperatures. Different deposition processes have almost no effect on the high-temperature performance of the DED Al-Cu alloy, and the deposition process can be selected according to the product’s structure.

Effects of Depositional Processes in Submarine Canyons and Distribution of Gas Chimneys on Gas Hydrate Accumulation in the Shenhu Sea Area, Northern South China Sea

Previous gas hydrate production tests conducted by the Guangzhou Marine Geological Survey (GSGM) in 2017 and 2020 indicated the great potential of gas hydrates in the Shenhu Sea area in the Pearl River Mouth Basin (PRMB), China. In this study, the effects of deposition processes in submarine canyons and the distribution of gas chimneys on gas hydrate accumulation were investigated using high-resolution two- dimensional (2D) and three-dimensional (3D) seismic data. Four intact submarine canyons were identified in the study area. Five deepwater depositional elements are closely related to submarine canyons: lateral accretion packages (LAPs), basal lags, slides, mass transport deposits (MTDs), and turbidity lobes. MTDs and lobes with multiple stages outside the distal canyon mouth reveal that the sedimentary evolution of the canyon was accompanied by frequent sediment gravity flows. Gas chimneys originating from Eocene strata are generally up to 3 km wide and distributed in a lumpy or banded pattern. The analysis of seismic attributes confirmed fluid activity in these gas chimneys. Gas hydrates are mainly distributed in ridges among different canyons. Based on the gas sources of gas hydrates and depositional evolution of submarine canyons, depositional processes of sediment gravity flows in submarine canyons and the distribution of gas chimneys significantly affect the accumulation of gas hydrates. Based on these findings, this study establishes a conceptional model for the accumulation of gas hydrate, which can provide guidance in the prediction for favorable gas hydrates zones in the area and nearby.

Investigation of deposition technique and thickness effect of HfO2 film in bilayer InWZnO-based conductive bridge random access memory

In recent research on memristor of brain-mimicking integrated circuit (IC) architecture, the electrical performance of electrochemical metallization memory can be significantly improved by applying a bilayer switching structure. In this work, a novel amorphous semiconductor InWZnO (IWZO) is used as the main switching layer, and a bilayer structure with HfO2 is fabricated by different deposition technique. By surface and chemical composition analysis, the effect of deposition process and thickness of HfO2 have been fully explored. The bilayer memory inserted with 3 nm HfO2 formed by atomic layer deposition process exhibits excellent electrical properties, such as high endurance cycle (more than 2 × 103), better retention time (up to 2 × 104 s, 85 °C), relatively uniform resistance state distribution and low compliance current operation. Consequently, the low power electrochemical metallization memory with optimized HfO2 layer has great potential for next generation memory in pixel and three-dimensional brain-mimicking IC technology.

Determining the effects of depositional processes on consolidation behavior of sediment using shear-wave velocity

Compression behavior of sediments is crucial to geological engineering applications for ascertaining the deformation characteristics of the particular depositional environments. Unfortunately, obtaining the geotechnical parameters required to assess the compression behavior of sediments can be a costly and time-consuming undertaking. This study developed a general prediction equation that simulates the compression behavior of sediments. This developed equation is an exponential decline model that relates an increase of the shear-wave velocity to an increase of the mean effective stress. Consequently, the decrease of void ratio is presented as a continuous function of the shear-wave velocity. For this research, laboratory-derived sediment samples created to mimic actual sediments were isotopically consolidated during a consolidated undrained triaxial compression tests. The samples were prepared in the laboratory by mixing different percentages of fines and controlling the ratio of clay-to-silt fractions. Shear-wave velocity tests were performed during this consolidation testing using bender elements. The experimental constants needed for the prediction equation were well correlated to the depositional factors specifically characterized by percent fines, silt percent, and liquid limit that define better complexity of depositional processes.

The effects of depositional processes on benthic foraminiferal taphonomy in the Southeastern Yellow Sea of Korea

To understand the role of depositional processes on the distribution of benthic foraminifera, grain size analysis, paleontological statistics and textural analysis were conducted on three piston cores (Core Nos. 3, 7, 9) from the southeastern Yellow Sea of Korea. Two foraminiferal assemblages were defined by cluster analysis. The Cibicides lobatulus-Ammonia ketienziensis assemblage has low P.F/B.F, species diversity and evenness and high number of benthic foram. individuals/20 ml, and is interpreted as representing relict benthic foraminiferal assemblage comprising the upper layer of Core No. 7 and No. 9. The deposit of well sorted alternation layers of muddy sand and sandy mud in Core No. 9. is interpreted as being influenced by hydraulic sorting processes of higher wave and current especially during storm periods. The preservation of 13 Pseudorotalia gaimardii extracted from Core No. 7 confirmed that bed load transport was responsible for its heavily abraded and broken thick-walled tests. The Pseudoparrellan araensis assemblage is a recent benthic foraminiferal assemblage found in the modern homogeneous fine-grained mud facies corresponding to the uppermost part of HMB. It seemed that the apparent sorting phenomena and bed load transport of the benthic foraminifera are the result of turbidity currents which promulgated by rapid tidal currents formed during the last postglacial period in the southeastern Yellow Sea of Korea.

Response of radiation dosimeters based on in situ oxygen plasma post-treated CVD-diamond thin films to X-ray

Radiation dosimeters based on in situ oxygen plasma post-treated diamond thin films were fabricated in a simple sandwich configuration. Effects of deposition process, methane concentration, and in situ oxygen plasma post-treatment on the sensitivity of the devices to X-ray irradiation were investigated. X-ray response demonstrates that the cyclic deposition process could improve response sensitivity. The increase in methane concentration in the deposition gas mixture will worsen the irradiation response of the devices mainly resulted from the change of the orientation and purity of the films. X-ray photoelectron spectroscopy, photoluminescence, and Raman measurements suggest that in situ oxygen plasma post-treatment can effectively etch non-diamond phases and passivate the silicon-vacancy and nitrogen-vacancy defects of the diamond films, resulting in an increase in the sensitivity of the device by a factor of about 2. Time-dependent response to X-ray indicates that the extended period to achieve photocurrent signals stability for the devices is a limitation for promising applications in radiation dosimetry.

Effect of deposition processes on residual stress profiles along the thickness in (Ti,Al)N films

The effect of deposition processes on the distribution of residual stresses in the thickness of the (Ti,Al)N films prepared by arc ion plating (AIP) was investigated in the present work, which indicates that the stress distribution exhibits a “bell” shape and the maximum compressive stress appears in the layer near the surface. The residual stress increases with the thickness of a film and the substrate bias voltage, respectively. The stress distribution can be altered, and the adhesion of the film/substrate can be improved by optimizing the deposition parameters. Finally, a film with a thickness of 7.57 μm was successfully directly deposited on the substrate through optimizing the bias voltage.

Substrate Surface Morphology and Growth Evolution of Low Temperature Silicon Nitride on Transparent Plastics

AbstractSurface morphology and nucleation are important for forming electronic thin films on plastic substrates. We have used atomic force microscopy (AFM) with an oscillating cantilever to examine various transparent substrates, including 7059 glass, polyethylene terephthalate (PET), indium tin oxide (ITO)-coated PET, and polycarbonate, and studied the effect of deposition processes on these surfaces. Studies include: 1) differences in dielectric nucleation on plastics and glass; 2) dielectric growth evolution; and 3) the effect of plasma exposure on surface roughness. The surface morphology of the different substrate materials varied significantly with the PET showing the largest roughness values; all the polymers were more rough than typical 7059 glass (rms <0.5 nm). Furthermore, the initial nucleation on both polymers were different than on glass. Very thin layers (<30Å nominal thickness) of plasma deposited silicon nitride films on polycarbonate and glass produced flat, smooth surfaces, with rms roughness of ≈0.5 nm. On the PET substrates, the nitride growth began with broad, thin deposits and developed a coarse, large-grained structure as growth progressed. With exposure to a NH3 + N2 plasma, the glass and PET surfaces showed detectable changes in surface roughness, which are discussed below. These results demonstrate that plasma-deposited insulators nucleate and grow differently on plastic substrates than on glass, which has implications for electronic devices fabricated directly on plastics.

Amorphous phase appearance at NbSi interfaces

Amorphous material formation at interfaces of NbSi multilayers during deposition was studied by high resolution transmission electron microscopy. When NbSi multilayers were deposited at room temperature, the multilayers with modulation period L of 4 nm are in the amorphous state, and are composed of Nb-rich amorphous silicide layers and Si-rich amorphous silicide layers; however, when the multilayers were deposited at 200°C, a crystalline cubic Nb 3Si phase with AuCu 3 structure was formed in the multilayer samples. No crystalline Nb silicide was found when the multilayers, deposited at room temperature, were annealed at 320°C. The effects of deposition process on nucleation are discussed. Here the initial amorphization nucleation in NbSi multilayers deposited at room temperature is thermodynamically and kinetically favored.

Deposition process effect on crystalline structure of (Pb, La) TiO3thin films by multi – ion – beam reactive cosputtering technique

Abstract Multi—ion—beam reactive cosputtering (MIBRECS) technique is a promising technique for preparing multi—component oxide thin films. However, the deposition processes are critically important for preparing thin films with prospected stoichiometry and good quality. In this paper, the effect of deposition processes, such as substrate temperature, ion beam energy and current, and the postdeposition annealing conditions on the composition and crystalline structure of (Pb, La) TiO3 ferroelectric thin films prepared by MIBRECS technique are reported.

The effect of deposition process on the magnetic properties of coupled permalloy thin films

Double layer thin films of permalloy (layer thickness 200–1300 Å) with tantalum (50 Å) as a nonmagnetic spacer have been prepared by e-beam evaporation. The effect of deposition parameters, especially the substrate temperature on the magnetic properties of these films has been examined. The coercivity(Hc) of the double layer films was found to be very sensitive to the substrate temperature in the permalloy layer thickness range of 200–600 Å. The coercivity of the films deposited at 40 °C is lower than at 300 °C and is almost independent of the Permalloy layer thickness. The XRD patterns and STM images of these two films exhibit large differences in permalloy grain size and grain orientation. However, the Hc of the single layer films deposited under the same conditions as the double layer films shows no significant change in this thickness region. The results indicate that the change of interface condition is primarily responsible for the Hc variation in the coupled films deposited at different substrate temperatures and strongly suggest that interface roughness plays a dominant role in the coupling between the permalloy layers.

Geotechnical properties of sediment cores from the Southeastern Yellow Sea: effects of depositional processes

Geotechnical properties of sediment cores from the Southeastern Yellow Sea: effects of depositional processes

Geotechnical properties of sediment cores from the southeastern yellow sea: Effects of depositional processes

Abstract Geotechnical properties of 20 scattered sediment cores from the southeastern Yellow Sea reveal that sediments contain certain common characteristics indicative of depositional processes. Silty and sandy sediments off the Taean Peninsula are largely consolidated and extensively bioturbated. Further seaward sandy sediments are consolidated in which sands are well sorted and shell fragments are scattered. In contrast, muddy sediments near the mouth of the Keum River are high in water and clay contents and low in shear strength. Water content increases with depth, but shear strength decreases. Fine sediments derived from the Keum River are restricted nearshore along the coast. Off the southwestern coast off Mokpo, sediments consist of well‐sorted silty layers and laminae with various degrees of bioturbation, which result in depth variations in water content and shear strength. Here, individual silty layers and laminae support the evidence of resuspension and deposition by strong tidal (and nearshore)...