scholarly journals Effects of Current on Arc Fabrication of Cu Nanoparticles

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
M. Z. Kassaee ◽  
F. Buazar ◽  
E. Motamedi
Keyword(s):  
Thermal Stability ◽  
Distilled Water ◽  
Face Centered Cubic ◽  
Cu Nanoparticles ◽  
Dta Analysis ◽  
Face Centered ◽  
Average Size ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Sem Analyses

Arc-fabricated copper nanoparticles (Cu Nps) size, morphology and the crystalline structure, as well as the yields of Nps appear sensitive to the applied currents (50–160 A) in distilled water. The results indicate that the sizes of Cu Nps are directly proportional to the currents employed. At 50 A, TEM, XRD, and SEM analyses show fabrication of relatively purest, the most dispersed, face-centered cubic (fcc) brown Cu Nps with rather smallest average size of 20 nm. At the same current, the TGA-DTA analysis reveals neither weight loss nor gain, indicating thermal stability of the fabricated Cu Nps.

Synthesis of Papercut-Like Carbon Sheets by a Simple Pyrolysis Method

2011 ◽  
Vol 239-242 ◽  
pp. 544-547
Author(s):  
Ling Ling Zhu ◽  
Pei Pei Xiao ◽  
Yi Tai Qian
Keyword(s):  
Thermal Stability ◽  
Powder Diffraction ◽  
Amorphous Carbon ◽  
Calcium Carbide ◽  
X Ray ◽  
Prepared Sample ◽  
Pyrolysis Method ◽  
Average Size ◽  
20 Nm ◽  
Thermal Stability Of

In this study, papercut-like carbon sheets with an average size of about 20 nm in thickness have been successfully synthesized by the pyrolysis of tetrachloromethane and calcium carbide in an autoclave in 600 °C in the existence of alloy (Fe-Co-Ni). The X-ray powder diffraction (XRD) reveals amorphous carbon nature of the as-prepared sample. The thermal stability of the as-prepared sample was also studied.

Thermal Stability of CrWN Glass Molding Coatings after Vacuum Annealing

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 198 ◽  
Author(s):  
Xinfang Huang ◽  
Zhiwen Xie ◽  
Kangsen Li ◽  
Qiang Chen ◽  
Yongjun Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electron Microscope ◽  
Vacuum Annealing ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
X Ray ◽  
Glass Molding ◽  
Annealed Coating ◽  
Face Centered ◽  
Thermal Stability Of

CrWN glass molding coatings were deposited by plasma enhanced magnetron sputtering (PEMS). The microstructure and thermal stability of these coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscope, atomic force microscope and nanoindentation tests. The as-deposited coating exhibited an aggravated lattice expansion resulting in a constant hardness enhancement. The vacuum annealing induced surface coarsening and the spinodal decomposition of the coating accompanied by the formation of nm-sized c-CrN, c-W2N, and h-WN domains. The annealed coating with low W content had mainly a face-centered cubic (f.c.c) matrix, strain fields caused by lattice mismatch caused hardness enhancement. Following an increase in W content, the annealed coating showed a mixed face-centered cubic (f.c.c) and hexagonal close-packed (h.c.p) matrix. The large volume fraction of h-WN phases seriously weakened the coating strengthening effect and caused an obvious drop in hardness.

scholarly journals Green Synthesis and Catalytic Activity of Silver Nanoparticles Based on Piper chaba Stem Extracts

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1777 ◽  
Author(s):  
Md. Mahiuddin ◽  
Prianka Saha ◽  
Bungo Ochiai
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Ftir Spectroscopy ◽  
Visual Observation ◽  
Face Centered Cubic ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Face Centered ◽  
Average Size

A green synthesis of silver nanoparticles (AgNPs) was conducted using the stem extract of Piper chaba, which is a plant abundantly growing in South and Southeast Asia. The synthesis was carried out at different reaction conditions, i.e., reaction temperature, concentrations of the extract and silver nitrate, reaction time, and pH. The synthesized AgNPs were characterized by visual observation, ultraviolet–visible (UV-vis) spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), energy dispersive x-ray (EDX), and Fourier transform infrared (FTIR) spectroscopy. The characterization results revealed that AgNPs were uniformly dispersed and exhibited a moderate size distribution. They were mostly spherical crystals with face-centered cubic structures and an average size of 19 nm. The FTIR spectroscopy and DLS analysis indicated that the phytochemicals capping the surface of AgNPs stabilize the dispersion through anionic repulsion. The synthesized AgNPs effectively catalyzed the reduction of 4-nitrophenol (4-NP) and degradation of methylene blue (MB) in the presence of sodium borohydride.

Synthesis of Fine Nickel Powders by Solvothermal Method

2007 ◽  
Vol 334-335 ◽  
pp. 1145-1148 ◽  
Author(s):  
Yin Ye ◽  
Fang Li Yuan ◽  
Li Min Zhou ◽  
Hai Tao Huang
Keyword(s):  
Thermal Stability ◽  
Chemical Reduction ◽  
Spherical Shape ◽  
Butyl Alcohol ◽  
Nickel Powders ◽  
Good Crystallinity ◽  
Average Size ◽  
Solvothermal Conditions ◽  
Thermal Stability Of ◽  
Fine Nickel

Fine nickel powders have been prepared by chemical reduction between nickel acetate and alcohol under solvothermal conditions. The effect of adding surfactant and varying solvent on the particle size of the as-synthesized nickel powders have been explored. SEM, XRD and TG were employed to characterize the size, morphology, crystalline structure and the thermal stability of the as-synthesized nickel powders. It is revealed that the FCC-structured nickel powders are of uniform spherical shape with good crystallinity and thermal stability. Typically, nickel powders with an average size of 300 nm were obtained at 200°C for 8 h using 0.04 mol/L solution of Ni(CH3COO)2·4H2O in n-butyl alcohol under solvothermal conditions.

Thermal Stability of Ni40Ti40Nb20 and Ni32Ti48Nb20 Tapes Obtained by Rapid Solidification Technique

2012 ◽  
Vol 188 ◽  
pp. 41-45
Author(s):  
György Thalmaier ◽  
Ioan Vida-Simiti ◽  
N. Jumate ◽  
Viorel Aurel Şerban ◽  
C. Codrean ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Purity ◽  
Elevated Temperatures ◽  
Graphite Crucible ◽  
Argon Atmosphere ◽  
Membrane Reactors ◽  
Master Alloys ◽  
Selective Membrane ◽  
Dta Analysis ◽  
Thermal Stability Of

Nickel–titanium- group 5A metal (V, Nb, Ta, Zr) alloys are known as promising hydrogen-selective membrane materials. They can potentially be used in membrane reactors, which can produce high-purity H2 and CO2 streams from coal-derived syngas at elevated temperatures. The master alloys were prepared by arc melting using high purity metals in a Ti-gettered argon atmosphere. The alloys were melted several times in order to improve homogeneity. The ingots were induction-melted under a high-purity argon atmosphere in a quartz tube and graphite crucible injected through a nozzle onto a Cu wheel to produce rapidly solidified amorphous ribbons. Thermal stability of the Ni40Ti40Nb20 and Ni32Ti48Nb20 thin tapes has been examined using DTA analysis.

Thermal Stability and Failure Mechanisms of Au/Tiw(N)/Si and Au/TiW(N)/Si02/Si Systems

1996 ◽  
Vol 427 ◽  
Author(s):  
C. R. Chen ◽  
L. J. Chen
Keyword(s):  
Thermal Stability ◽  
Failure Mechanisms ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Single Face ◽  
Face Centered ◽  
The Stability ◽  
Ar Gas

AbstractThermal stability and failure mechanisms of Au/TiW(N)/Si and Au/TiW(N)/SiO2/Si systems have been studied by both conventional and high-resolution transmission electron microscopy, X- ray diffraction and Auger electron spectroscopy. For films deposited in Ar gas containing 20% N2, a single face-centered-cubic phase was the only crystalline phase detected to form. The samples were found to remain stable after annealing at 700 °C for 30 min. The stability temperature for Au/TiW(N)(Ar:N2=80:20)/SiO2/Si samples was found to be higher than those of Au/TiW(N) (Ar:N2=90:10)/SiO2/Si and Au/TiW/SiO2/Si samples.

scholarly journals Nitridated Ca2NaMg2V3O12: Eu3+ Vanadate Garnet Phosphor-in-Glass

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2996
Author(s):  
Damian Pasinski ◽  
Jerzy Sokolnicki
Keyword(s):  
Thermal Stability ◽  
Single Phase ◽  
Low Energy ◽  
Color Temperature ◽  
Garnet Structure ◽  
Air Atmosphere ◽  
Ammonia Atmosphere ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Emission Quantum Yield

In this study, Ca2NaMg2V3O12 coordination compound undoped and doped with Eu3+ obtained in the air and ammonia atmosphere by solid-state reaction was investigated. Ca2NaMg2V3O12: Eu3+ obtained in the ammonia atmosphere was then investigated as a phosphor-in-glass (PiG). Annealed Ca2NaMg2V3O12: Eu3+ phosphor forms a single phase with the cubic garnet structure and Ia3d space group. Nitridation in ammonia causes a widening of a VO43− group emission band on the low energy side and it red-shifts by 20 nm. The emission of Eu3+ is extended as compared to the non-nitridated phosphor. Ca2NaMg2V3O12: Eu3+ after nitridation shows higher emission quantum yield (QY): 49 vs. 45 and lower correlated color temperature (CCT) and 4179 vs. 4998 as compared to phosphor without nitridation. The QY for PiG is 55. The thermal stability of nitridated phosphors is superior to phosphor obtained in the air atmosphere and is further enhanced for PiG.

Synthesis and Thermal Stability of Nontransformable Tetragonal (ZrO2)0.96(REO1.5)0.04 (Re=Sc3+, Y3+) Nanocrystals

2013 ◽  
Vol 334-335 ◽  
pp. 60-64 ◽  
Author(s):  
Mohammad Reza Loghman-Estark ◽  
Reza Shoja Razavi ◽  
Hossein Edris
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Scanning Electron

Scandia, yttria doped zirconia ((ZrO2)0.96(REO1.5)0.04(RE=Sc3+, Y3+)) nanoparticles were prepared by the modified sol-gel method. The microstructure of the products was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Thermal stabillity of SYSZ nanocrystals were also investigated. The SYSZ nanocrystals synthesized with EGM:Zr+4mole ratio 4:1, calcined at 700°C, have average diameter of ~20 nm.

Crystallization of Ni-Cr-Si-B and Ni-Cr-Fe-Si-B Amorphous Alloys

2014 ◽  
Vol 216 ◽  
pp. 35-38 ◽  
Author(s):  
Cosmin Codrean ◽  
Dragoş Buzdugan ◽  
Ramona Lǎzar ◽  
Viorel Aurel Şerban ◽  
Ion Mitelea
Keyword(s):  
Thermal Stability ◽  
Chemical Composition ◽  
Rapid Solidification ◽  
Amorphous Alloys ◽  
Structural Characteristics ◽  
Glass Forming Ability ◽  
Glass Forming ◽  
Melting Temperatures ◽  
Dta Analysis ◽  
Thermal Stability Of

Ni based amorphous alloys with Si and B, which can also, contains Fe and Cr, prepared by rapid solidification, have low melting temperatures. This fact increases their susceptibility to be joined by welding and brazing. The glass forming ability (GFA) is conditioned also by the crystallization delay, due to certain chemical composition of the alloys. The thermal stability of these alloys was revealed by DTA analysis and structural characteristics were investigated by XRD. Applying an annealing at temperatures between 420°C and 540°C, with 30 minutes maintaining time, allowed the investigation of phase occurred during the crystallization and the estimation of the crystalline grains dimensions.

The Influence of Alkaline Treatment on Mechanical Properties and Morphology of Rice Husk Fibre Reinforced Polylactic Acid

2014 ◽  
Vol 911 ◽  
pp. 13-17 ◽  
Author(s):  
Abdullah Farah Dina ◽  
Sa’ad Siti Zaleha ◽  
Bonnia Noor Najmi ◽  
Ibrahim Nor Azowa
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Brittle Fracture ◽  
Polylactic Acid ◽  
Rice Husk ◽  
Alkaline Treatment ◽  
Distilled Water ◽  
Internal Mixer ◽  
Fesem Micrographs ◽  
Thermal Stability Of

This study focuses on the influence of surface treatment and fibre sizes on mechanical behavior, physical properties and morphology of rice husk fibre (RHF) reinforced polylactic-acid (PLA). Modified RHF was prepared by using 6w.t.% sodium hydroxide (NaOH) and distilled water. PLA composite reinforced with 25w.t.% volume fractions of modified RHF was mixed using the internal mixer and fabricated by the mini injection moulding. Tensile and flexural strength results showed that the PLA composite with 100, 200 and 500μm particles sizes of water treated fibre are much higher than those of alkaline treated. DSC measurement was performed and indicated that the Tg,Tmand ΔHmof PLA reduced after reinforcement with water treated and alkaline treated fibres. TGA results showed that the treatment reduced the thermal stability of the PLA. FESEM micrographs for flexural fractured surfaces of composites showed micro crack and pores due to brittle fracture of the PLA matrix adjacent to the fibre as a result of the brittle nature of the PLA resin.

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