scholarly journals Characterization of Thermally Treated Gas-Atomized Al 5056 Powder

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4051
Author(s):  
Kyle Tsaknopoulos ◽  
Caitlin Walde ◽  
Derek Tsaknopoulos ◽  
Victor Champagne ◽  
Danielle Cote
Keyword(s):  
Natural Aging ◽  
Thermal Treatments ◽  
Secondary Phases ◽  
Transmission Electron ◽  
The Stability ◽  
New Applications ◽  
And Storage ◽  
Insight Into ◽  
Thermally Treated

Aluminum 5056 is a work-hardenable alloy known for its corrosion resistance with new applications in additive manufacturing. A good understanding of the secondary phases in Al 5056 powders is important for understanding the properties of the final parts. In this study, the effects of different thermal treatments on the microstructure of Al 5056 powder were studied. Thermodynamic models were used to guide the interpretation of the microstructure as a function of thermal treatment, providing insight into the stability of different possible phases present in the alloy. Through the use of transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS), combined with thermodynamic modeling, a greater understanding of the internal microstructure of Al 5056 powder has been achieved in both the as-atomized and thermally treated conditions. Evidence of natural aging within these powders was observed, which speaks to the shelf-life of these powders and the importance of proper treatment and storage to maintain consistent results.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

Effect of pH and temperature on the infectivity of human coronavirus 229E

1989 ◽  
Vol 35 (10) ◽  
pp. 972-974 ◽  
Author(s):  
Alain Lamarre ◽  
Pierre J. Talbot
Keyword(s):  
Incubation Period ◽  
Storage Conditions ◽  
Viral Infectivity ◽  
Human Coronavirus ◽  
Virus Growth ◽  
The Stability ◽  
And Storage ◽  
Influence Of Ph ◽  
Human Coronavirus 229E

The stability of human coronavirus 229E infectivity was maximum at pH 6.0 when incubated at either 4 or 33 °C. However, the influence of pH was more pronounced at 33 °C. Viral infectivity was completely lost after a 14-day incubation period at 22, 33, or 37 °C but remained relatively constant at 4 °C for the same length of time. Finally, the infectious titer did not show any significant reduction when subjected to 25 cycles of thawing and freezing. These studies will contribute to optimize virus growth and storage conditions, which will facilitate the molecular characterization of this important pathogen.Key words: coronavirus, pH, temperature, infectivity, human coronavirus.

Structural Evolution Upon Annealing of Multi-Layer Si/Fe Thin Films Prepared by Magnetron Sputtering

2007 ◽  
Vol 561-565 ◽  
pp. 1161-1164
Author(s):  
Xiao Na Li ◽  
Bing Hu ◽  
Chuang Dong ◽  
Xin Jiang
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Room Temperature ◽  
Structural Evolution ◽  
Radio Frequency Magnetron Sputtering ◽  
Transmission Electron ◽  
Direct Band ◽  
The Stability ◽  
Sputtering System

Fe/Si multi-layer films were fabricated on Si (100) substrates utilizing radio frequency magnetron sputtering system. Si/β-FeSi2 structure was found in the films after the deposition. Structural characterization of Fe-silicide sample was performed by transmission electron microscopy, to explore the dependence of the microstructure of β-FeSi2 film on the preparation parameters. It was found that β-FeSi2 particles were formed after the deposition without annealing, whose size is less than 20nm ,with a direct band-gap of 0.94eV in room temperature. After annealing at 850°C, particles grow lager, however the stability of thin films was still good.

scholarly journals Characterization of Pd Impurities and Finite-Sized Defects in Detector Grade CdZnTe

2011 ◽  
Vol 1341 ◽  
Author(s):  
M.C. Duff ◽  
J.P. Bradley ◽  
Z.R. Dai ◽  
N. Teslich ◽  
A. Burger ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cubic Phase ◽  
Secondary Phases ◽  
Detector Performance ◽  
X Ray ◽  
Metal Impurities ◽  
Transmission Electron ◽  
Large Numbers ◽  
Topographic Imaging

ABSTRACTSynthetic CdZnTe or “CZT” crystals are highly suitable for γ-spectrometers operating at the room temperature. Secondary phases (SP) in CZT are known to inhibit detector performance, particularly when they are present in large numbers or dimensions. These SP may exist as voids or composites of non-cubic phase metallic Te layers with bodies of polycrystalline and amorphous CZT material and voids. Defects associated with crystal twining may also influence detector performance in CZT. Using transmission electron microscopy, we identify two types of defects that are on the nano scale. The first defect consists of 40 nm diameter metallic Pd/Te bodies on the grain boundaries of Te-rich composites. Although the nano-Pd/Te bodies around these composites may be unique to the growth source of this CZT material, noble metal impurities like these may contribute to SP formation in CZT. The second defect type consists of atom-scale grain boundary dislocations. Specifically, these involve inclined “finite-sized” planar defects or interfaces between layers of atoms that are associated with twins. Finite-sized twins may be responsible for the subtle but observable striations that can be seen with optical birefringence imaging and synchrotron X-ray topographic imaging.

Instability of Si3N4/, SiC/, and MoSi2/ethanol suspensions

2003 ◽  
Vol 18 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Yoko Fukada ◽  
Patrick S. Nicholson
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Ammonium Hydroxide ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Tetramethyl Ammonium Hydroxide ◽  
Powder Addition ◽  
The Stability ◽  
Insight Into

Time-dependent suspension behavior is reported for nonoxide ceramic powders (Si3N4, SiC, and MoSi2) in ethanol. The suspension pH (and therefore the stability) changed with time. X-ray photoelectron spectroscopy, inert gas fusion, inductively coupled plasma, and high-resolution transmission electron microscopy were used to track changes of surface chemistry. The adsorption of the base, tetramethyl ammonium hydroxide (TMAH), is examined. The pH drop on powder addition to pure EtOH was used to gain insight into the role of TMAH coverage of the powder surfaces.

scholarly journals Microstructure Characterization of Welds in X5CrNiCuNb16-4 Steel in Overaged Condition

2019 ◽  
Vol 19 (1) ◽  
pp. 57-69
Author(s):  
A. Ziewiec ◽  
A. Zielińska-Lipiec ◽  
J. Kowalska ◽  
K. Ziewiec
Keyword(s):  
Electron Microscopy ◽  
Aging Time ◽  
Energy Dispersive Spectrometry ◽  
Solution Treatment ◽  
X Ray Diffraction ◽  
Density Distributions ◽  
Transmission Electron ◽  
Steel Welds ◽  
The Stability

AbstractThe paper presents the results of the investigation of microstructure of the welded X5CrNiCuNb16-4 (17-4PH) steel after solution treatment and aging at 620°C for different periods. The microstructure and the phase composition of the steel was investigated using light microscopy (LM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM) and the X-ray diffraction (XRD). Hardness was measured for samples aged at different times. Density distributions of Cu precipitates were established. The investigation has shown that the microstructure of the X5CrNiCuNb16-4 steel welds after aging at 620 ° C consists of tempered martensite, fine Cu precipitates and austenite. It was observed that the size of the Cu precipitates increases with increasing the aging time, what affects the decrease of hardness. Simultaneously, the quantity of reversed austenite increases with increase of aging time. It was revealed that enrichment of the austenite in Ni, Cu and C affects the increase of Ms, but this factor does not determine the stability of austenite.

scholarly journals Effect of Prestorage Thermal Treatments, Vacuum Infused Mycostatic Treatments, and Storage Relative Humidity on the Stability of Chinese Chestnuts

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 644f-644
Author(s):  
Durward Smith ◽  
Joseph D. Norton
Keyword(s):  
Relative Humidity ◽  
Vacuum Treatment ◽  
Test Methods ◽  
Thermal Treatments ◽  
Weight Losses ◽  
Perishable Commodity ◽  
Efficient Processing ◽  
The Stability ◽  
Processing And Storage ◽  
And Storage

Chinese chestnuts (Castanea molissima Blume) are a highly perishable commodity which requires artificial storage means and is easily spoiled by fungi. This investigation was designed to develop processes and adapt equipment for more efficient processing and storage of Chinese chestnuts, establish parameters for optimum fresh storage, and to compare the yields and qualities of the chestnuts processed by the test methods. Chinese chestnuts were prepared for fresh storage by vacuum infusing mycostatic solutions and modified starch coatings inside the shells. Vacuum treatment facilitated perfect contact of these solutions with the surfaces of the kernels, and was a more rapid method than atmospheric or pressure soaking methods. Vacuum infused pretreatments limited desiccation, minimized spoilage, reduced storage weight losses, and yielded products with better color and texture than conventional storage. Thermal treatments for surface pasteurization were defined. A storage relative humidity of 87% was found to be optimal.

scholarly journals Characterization of the Spindle Morphology Nanomicelles Assembled from Sericin and Gelatin

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Xiaozhou Su ◽  
Lei Li ◽  
Weihan Huang
Keyword(s):  
Electron Microscopy ◽  
Protein Concentration ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Ft Ir ◽  
And Storage ◽  
Ft Ir Spectroscopy

Complex nanomicelles were prepared by sericin and type A gelatin with molecular weight of 5789 Da and 128664 Da separately. The assembling conditions were as follows: mass ratio (sericin/gelatin) was 1 : 1, protein concentration was 0.5%, temperature was 35°C, and assembling time was 18 hours. Scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and dynamic light scattering (DLS) were conducted to observe and characterize the complex nanomicelles. Results showed that the complex sericin/gelatin micelles was a kind of nanospindle micelles. The micelles had high electrochemical stability, thermal stability, antidilution stability, and storage stability.

scholarly journals The Role of Hydraulic Hysteresis on the Hydrological Response of Pyroclastic Silty Covers

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 628 ◽  
Author(s):  
Guido Rianna ◽  
Luca Comegna ◽  
Luca Pagano ◽  
Luciano Picarelli ◽  
Alfredo Reder
Keyword(s):  
Slope Failure ◽  
Hysteretic Behavior ◽  
Recent Experience ◽  
Hydrological Response ◽  
Hydraulic Hysteresis ◽  
The Stability ◽  
Hydrological Effects ◽  
Insight Into

A significant part of the recent geotechnical literature concerning pyroclastic soils is focused on the characterization of the hydrological effects of precipitations and their implications for the stability conditions of unsaturated sloping covers. Recent experience shows that suction-induced strength reduction is influenced by various factors including hydraulic hysteresis. A deeper insight into the hysteretic water retention behavior of these materials and its effects upon their response to dry/wetting conditions is a major goal of this paper, which exploits the data provided by the monitoring of a volcanic ash. Based on the parameters retrieved from data calibration, the hydrological response of a virtual slope subject to one-dimensional rainfall infiltration is investigated by numerical analyses and compared with the results obtained through the usually adopted non-hysteretic approaches. The analysis demonstrates that considering the hysteretic behavior may be crucial for a proper evaluation of the conditions leading to slope failure.

Structural Characterization of Crystalline Si-C-N Films

1997 ◽  
Vol 498 ◽  
Author(s):  
E. G. Wang ◽  
Cheng-Zhang Wang ◽  
Changfeng Chen ◽  
Yan Chen
Keyword(s):  
Electron Microscopy ◽  
Structural Characterization ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Hot Filament ◽  
Microscopy Images ◽  
Insight Into

ABSTRACTHigh quality crystalline Si-C-N films on silicon substrate have been synthesized by bias-assisted hot filament chemical vapor deposition (CVD) using a gas mixture of nitrogen and methane. Scanning electron microscopy images show that the Si-C-N clusters are composed of many columnar crystals with hexagonal facets. X-ray diffraction and transmission electron microscopy analyses confirm the formation of Si-C-N crystals with lattice parameters a=7.06Å and c=2.72Å. First principles calculations are performed for β-Si3–nCnN4 (n=0,1,2,3). The calculated results support the experimental structural characterization and provide further insight into the property of the system. With increasing amount of C substitution, the bulk modulus progressively increases to 4.44 Mbar, comparable to that of diamond (4.43 Mbar), and both a and c are reduced but the ratio c/a shows little variation.

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