scholarly journals A comparative study between the addition of nano and micro-particles of Co3O4 on the electrical and microstructural properties of a ceramic system based on SnO2

2019 ◽  
Vol 66 (1) ◽  
pp. 47
Author(s):  
M. I Miranda López ◽  
M. B. Hernández Hernández ◽  
B. S. Vera Barrios ◽  
A. Toxqui Teran ◽  
J. A. Aguilar Martinez
Keyword(s):  
Comparative Study ◽  
Sintering Temperature ◽  
Electrical Breakdown ◽  
Rietveld Analysis ◽  
Nano Particles ◽  
Particle Sizes ◽  
Linear Coefficient ◽  
Ohmic Behavior ◽  
Micro Particles ◽  
Maximum Value

A comparative study between the addition of Co3O4 micro-particles and nano-particles as densifying dopant of a SnO2 based varistor system was conducted. The ceramic composition was (99.9-X) %SnO2–X %Co3O4–0.05 %Cr2O3–0.05 %Nb2O5 where X = 0, 0.5, 1.0, 2.0 and 4.0 mol%. Two particle sizes of Co3O4 were used (~5 µm and ~50 nm). The addition of 0.5 mol% of Co3O4 nano-particles promoted an increase of grain size of sintered samples up to 7.9 µm, that is, the maximum value among all variations.  Characterization techniques such as TGA, DTA, XRD, and Rietveld analysis revealed a decrease of 16 ºC in the formation temperature of Co2SnO4 as well as an increase of 2.6 wt% in the amount of said phase with the use of 4.0 mol% of Co3O4 nano-particles in comparison with micro-particles. Statistical analysis indicated that the addition of nano-particles of Co3O4 yield better repeatability on densification of ceramic samples. Residual porosity also was decreased. Electrical breakdown and non-linear coefficient values correspond to a non-ohmic behavior with potential application on manufacture of high voltage varistors. The findings of this work can be used as a reference for conducting a later study to improve the electrical properties or even to lower the sintering temperature.

scholarly journals Processing of nano-micro copper materials for the production of conductive circuits

2021 ◽  
Author(s):  
◽  
Bahaa H. Abbas
Keyword(s):  
Sintering Temperature ◽  
Cost Effective ◽  
Pulse Frequency ◽  
Nano Particles ◽  
Conductivity Enhancement ◽  
Power Pulse ◽  
Micro Particles ◽  
Sintering Time ◽  
Sintering Conditions ◽  
Thermal Sintering

Copper inks potentially provide a cost-effective alternative to silver for printed electronic circuits. In glass-based applications such as PV or smart glass, they can provide a means of conductivity enhancement or additional functionality. Three inks consisting of a mixture of nano and micro copper particles were systematically studied to examine the relationship between sintering temperature, sintering time and gaseous environment on the electrical qualities of the sintered printed films deposited on FTO coated glass. There is a definite interaction between the particulate nature of the ink, the sintering conditions, and the conductive properties of the film. Films containing only nano-particles provide the most conductive films with optimum sintering conditions of temperature of 225 °C for 60 minutes. The inclusion of micro particles increased the ideal sintering temperature but lowered the sintering time. An ink containing an equal mixture of nano and micro particles exhibited the lowest performance. This could be attributed to partial oxidation of the nano-particles along the conductive path, which occurs as a result of the presence of the micro particles. Other samples were photonically sintered using a PulseForge 1200 laboratory photonic sintering unit where the number of pulses, pulse power, pulse frequency and the intra pulse gap could be varied. An initial optimization study identified an operational range of photonic energy profile. The best possible line conductivity obtained using these optimum conditions was around a 1/3 of that obtained by conventional thermal sintering. This relative conductivity of photonically sintered features further deviated from conventionally sintered features as the film thickness increased and as the line width reduced. Laser / NIR techniques were found ineffective to sinter the copper ink used in this study. The possibility to manually blend copper and silver paste ink was investigated and an optimum blend of 25% silver and 75% copper could be used which had maintained conductivity, cost, and adhesion benefits.

scholarly journals Synthesis of Hydronium-Potassium Jarosites: The Effect of pH and Aging Time on Their Structural, Morphological, and Electrical Properties

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 80
Author(s):  
Elías Hernández-Lazcano ◽  
E. Cerecedo-Sáenz ◽  
J. Hernández-Ávila ◽  
Norman Toro ◽  
T. V. K. Karthik ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Aging Time ◽  
Anode Materials ◽  
Lithium Ion ◽  
Rietveld Analysis ◽  
Morphological Properties ◽  
Particle Sizes ◽  
Ph Values ◽  
Hydronium Jarosite ◽  
Cationic Site

Structural and morphological properties of hydronium-potassium jarosite microstructures were investigated in this work, and their electrical properties were evaluated. All the microstructures were synthesized at a very low temperature of 70 °C with a reduced reaction time of 3 h. An increase in the pH from 0.8 to 2.1 decreased the particle sizes from 3 µm to 200 nm and an increase in the aging time from zero, three, and seven days resulted in semispherical, spherical, and euhedral jarosite structures, respectively. The Rietveld analysis also confirmed that the amount of hydronium substitution by potassium in the cationic site increased with an increase in pH. The percentages of hydronium jarosite (JH)/potassium jarosite (JK) for pH values of 0.8, 1.1, and 2.1 were 77.72/22.29%, 82.44/17.56%, and 89.98/10.02%, respectively. Microstructures obtained in this work were tested as alternative anode materials and the voltage measured using these electrodes made with hydronium-potassium jarosite microstructures and graphite ranged from 0.89 to 1.36 V. The results obtained in this work show that with reduced particle size and euhedral morphology obtained, modified jarosite microstructures can be used as anode materials for improving the lifetime of lithium-ion batteries.

Effects of Particles Size of Nanosilica on Properties of Polybenzoxazine Nanocomposites

2015 ◽  
Vol 659 ◽  
pp. 394-398 ◽  
Author(s):  
Nutthaphon Liawthanyarat ◽  
Sarawut Rimdusit
Keyword(s):  
Particle Size ◽  
Silica Nanoparticles ◽  
Primary Particle ◽  
Mechanical And Thermal Properties ◽  
Particle Sizes ◽  
Barrier Effect ◽  
Degradation Temperature ◽  
Maximum Value ◽  
Wetting Behaviors ◽  
Composite Samples

Polybenzoxazine nanocomposites filled with three different sizes of silica nanoparticles are investigated for their mechanical and thermal properties. In this research, silica nanoparticles with primary particle sizes of 7, 14 and 40 nm were incorporated in polybenzoxazine matrix at a fixed content of 3% by weight. From the experimental results, the storage modulus of the polybenzoxazine nanocomposite was found to systematically increase with decreasing the particle sizes of nanosilica suggesting better reinforcement of the smaller particles. Glass transition temperature was found to slightly increase with the addition of the silica nanoparticles. The uniformity of the composite samples were also evaluated by thermogravimetric analysis to show good dispersion of the silica nanoparticles in the composite samples as a result of high processability of the benzoxazine resin used i.e. low A-stage viscosity with good wetting behaviors. Degradation temperature at 5% weight loss (Td,5) of polybenzoxazine nanocomposites filled with different particle sizes of silica nanoparticles was found to increase from the value of 325 °C of the neat polybenzoxazine to the maximum value of about 340 °C with an addition of the nanosilica of the smallest particle size used. Finally, the smaller nanosilica particle size was also found to show more pronounced effect on Td,5enhancement of the composite samples as a result of greater barrier effect from larger surface area of the smaller particles.

scholarly journals Structural and magnetic study of metallo-organic YIG powder using 2-ethylhexanoate carboxylate-based precursors

2019 ◽  
Vol 33 (09) ◽  
pp. 1950100 ◽  
Author(s):  
S. Hosseinzadeh ◽  
P. Elahi ◽  
M. Behboudnia ◽  
M. H. Sheikhi ◽  
S. M. Mohseni
Keyword(s):  
Saturation Magnetization ◽  
Annealing Temperature ◽  
Sintering Temperature ◽  
Magnetic Behavior ◽  
Yttrium Iron ◽  
Organic Precursor ◽  
Maximum Value ◽  
Diffraction Peaks ◽  
Iron Garnet ◽  
Organic Decomposition

The crystallization and magnetic behavior of yttrium iron garnet (YIG) prepared by metallo-organic decomposition (MOD) method are discussed. The chemistry and physics related to synthesis of iron and yttrium carboxylates based on 2-ethylhexanoic acid (2EHA) are studied, since no literature was found which elucidates synthesis of metallo-organic precursor of YIG in spite of the literatures of doped YIG samples such as Bi-YIG. Typically, the metal carboxylates used in preparation of ceramic oxide materials are 2-ethylhexanoate (2EH) solvents. Herein, the synthesis, thermal behavior and solubility of yttrium and iron 2EH used in synthesis of YIG powder by MOD are reported. The crystallization and magnetic parameters, including saturation magnetization and coercivity of these samples, smoothly change as a function of the annealing temperature. It is observed that high sintering temperature of [Formula: see text] to [Formula: see text] promotes the diffraction peaks of YIG, therefore, we can conclude that the formation of YIG in MOD method increases the crystallization temperature. The maximum value of saturation magnetization and minimum value of coercivity and remanence are observed for the sample sintered at [Formula: see text] which are 13.7 emu/g, 10.38 Oe and 1.5 emu/g, respectively. This study cites the drawbacks in chemical synthesis of metallo-organic-based YIG production.

Comparative study of three magnetic nano-particles (FeSO4, FeSO4/SiO2, FeSO4/SiO2/TiO2) in plasmid DNA extraction

2016 ◽  
Vol 513 ◽  
pp. 68-76 ◽  
Author(s):  
H. Rahnama ◽  
A. Sattarzadeh ◽  
F. Kazemi ◽  
N. Ahmadi ◽  
F. Sanjarian ◽  
...  
Keyword(s):  
Comparative Study ◽  
Dna Extraction ◽  
Plasmid Dna ◽  
Nano Particles ◽  
Magnetic Nano Particles

SECOND HARMONIC GENERATION IN ZnO NANORODS

2010 ◽  
Vol 19 (03) ◽  
pp. 445-458 ◽  
Author(s):  
MALYAJ DAS ◽  
SHIVANI RANA ◽  
PRATIMA SEN
Keyword(s):  
Second Harmonic Generation ◽  
Comparative Study ◽  
Harmonic Generation ◽  
Nd:Yag Laser ◽  
Second Harmonic ◽  
Zno Nanorods ◽  
Harmonic Signal ◽  
Pulsed Nd:Yag Laser ◽  
Micro Particles ◽  
Second Harmonic Signal

A comparative study of the second harmonic generation in ZnO micro particles and nanorods has been experimentally studied by Kurtz technique using nanosecond pulsed Nd:YAG laser. The results have been theoretically explained by taking into account the quadrupole moment as well as surface nonlinearity. It was observed that the nanorods yield polarized second harmonic signal while the second harmonic signal obtained from the micro particles was unpolarized.

Cutting Performance and Wear Mechanisms of an Al2O3-Based Micro-Nano-Composite Ceramic Tool

2010 ◽  
Vol 443 ◽  
pp. 244-249 ◽  
Author(s):  
Yong Hui Zhou ◽  
Jun Zhao ◽  
Xing Ai
Keyword(s):  
Failure Modes ◽  
Cutting Tools ◽  
Tool Material ◽  
Composite Ceramic ◽  
Cutting Performance ◽  
Nano Particles ◽  
Ceramic Tool ◽  
Nano Composite ◽  
Micro Particles ◽  
1045 Steel

An Al2O3-based composite ceramic cutting tool material reinforced with (W, Ti)C micro-particles and Al2O3 micro-nano-particles was fabricated by using hot-pressing technique, the composite was denoted as AWT. The cutting performance, failure modes and mechanisms of the AWT micro-nano-composite ceramic tool were investigated via continuous turning of hardened AISI 1045 steel in comparison with those of an Al2O3/(W, Ti)C micro-composite ceramic tool SG-4 and a cemented carbide tool YS8. Worn and fractured surfaces of the cutting tools were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results of continuous turning revealed that tool lifetime of the AWT ceramic tool was higher than that of the SG-4 and YS8 tools at all the tested cutting speeds. The longer tool life of the AWT composite ceramic tool was attributed to its synergistic strengthening/toughening mechanisms induced by the (W, Ti)C micro-particles and Al2O3 nano-particles.

Mechanical strength characterization and modeling of hydroxyapatite/tricalcium phosphate biocomposite using the diametral-compression test

2021 ◽  
Vol 93 (3) ◽  
pp. 30403
Author(s):  
Mohammed Es-Saddik ◽  
Said Laasri ◽  
Abdelaziz Laghzizil ◽  
Jean-Michel Nunzi ◽  
Mohammed Taha ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Tricalcium Phosphate ◽  
Sintering Temperature ◽  
Rupture Strength ◽  
Mechanical Resistance ◽  
The Finite Element Method ◽  
Maximum Value ◽  
Strength Characterization ◽  
Powder Manufacturing ◽  
Diametral Compression Test

This study reports the enhanced mechanical resistance of the composite bioceramics of hydroxyapatite (HAP) and tricalcium phosphate (β-TCP) used as bone substitute. HAP/β-TCP mixture was prepared by wet mixing of powders and characterized. Effects of powder manufacturing and sintering temperature on the densification, microstructure and mechanical properties of the composite were studied. The rupture strength (σr) was calculated using the Brazilian test. At 1250 °C, the relative density and mechanical strength of the HAP/β-TCP ceramics reached the maximum value of 89% and 43 MPa, respectively. Experimental results were modeled by the finite element method to determine the stress distribution in the compacted disc.

Influence of cathode material type on the electrical breakdown behaviors of DC discharge

2020 ◽  
Vol 98 (8) ◽  
pp. 726-731
Author(s):  
F. Diab ◽  
W.H. Gaber ◽  
M.E. Abdel-kader ◽  
B.A. Soliman ◽  
M.A. Abd Al-Halim
Keyword(s):  
Cathode Material ◽  
Work Function ◽  
Breakdown Voltage ◽  
Cathode Materials ◽  
Electrical Breakdown ◽  
Ionization Efficiency ◽  
Parallel Plates ◽  
Maximum Value ◽  
Dc Discharge ◽  
Work Functions

Paschen curves were studied using different cathode materials such as magnesium, zinc, and carbon graphite by discharge in argon gas of a pressure range between 0.08 and 3 Torr using a parallel plates configuration. The first and second Townsend coefficients (α and γ, respectively) and the ionization efficiency (η) of different cathode materials were deduced from Paschen curves as a function of the reduced field (E/P). The minimum breakdown voltage was found to be about 242 V for Mg material, which has the lowest work function, while carbon graphite has a higher breakdown voltage of 283 V due to its higher work function. The second coefficient γ was increased as a function of E/P and has higher values for materials of lower work functions, and a similar trend of γ is obtained as a function of the ion mean energy. On the other hand, the first coefficient α has a reverse behavior with both E/P and the work function of the cathode materials compared with the second coefficient. The ionization efficiency of the three cathode materials is identical, as η depends only on the gas properties and not the cathode material. η has a maximum value of about 0.025 V−1 for an E/P of about 185 Vcm−1Torr−1, corresponding to the maximum ionizing ability of electrons. The validation of the breakdown results has been confirmed by conferring with other published experimental measurements.

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