Preparation and Thermoelectric Properties of Al2O3-Doped ZnO Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 562-564
Author(s):  
Xiu Rong Qu ◽  
De Chang Jia
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Testing Temperature ◽  
Cold Isostatic Pressing ◽  
Doped Zno ◽  
Co Precipitation ◽  
Zno Ceramics ◽  
Scanning Electron

Al2O3-doped ZnO ceramics were prepared via chemical co-precipitation processing. Zinc acetate, ammonia and Al2O3 powders are used as starting materials. Scanning electron microscopy (SEM) observations reveal that the doping of Al2O3 has an obvious influence on the microstructure of ZnO ceramics. Ordinary cold pressing and cold isostatic pressing (CIP) were used to prepare green compacts. The thermal conductivity and electrical conductivity of the Al2O3-doped ZnO ceramics were measured as a function of the testing temperature (0-900oC). Doping of Al2O3 is beneficial to improve thermoelectric (TE) properties of ZnO ceramics. CIP can also improve TE properties of Al2O3-doped ZnO ceramics.

USE OF NANOFLUIDS BASED ON CARBON NANOPARTICLES TO DISPLACE OIL FROM THE POROUS MEDIUM MODEL

2020 ◽  
Vol 6 (4) ◽  
pp. 141-157
Author(s):  
Yuri V. Pakharukov ◽  
Farid K. Shabiev ◽  
Ruslan F. Safargaliev ◽  
Boris S. Yezdin ◽  
Valery V. Kalyada
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Porous Medium ◽  
Synergistic Effect ◽  
Transition Region ◽  
Dimensional Structure ◽  
Hybrid Nanofluids ◽  
Scanning Electron

Graphene, due to its two-dimensional structure, has some unique properties. For example, the thermal conductivity and electrical conductivity of graphene are an order of magnitude higher than the thermal conductivity and electrical conductivity of copper. For this reason, graphene-based nanofluids are now used in many industries. Due to the effect of self-organization of graphene nanoparticles with hydrocarbon molecules, the use of graphene has become possible in the oil industry. Graphene-based nanofluids are used as a displacement fluid to increase the oil recovery coefficient. The displacing ability of graphene-based nanofluids is concentration dependent. An increase in the concentration of nanoparticles entails an increase in viscosity, which negatively affects the performance characteristics of the nanofluid. This problem is partially solved due to the synergistic effect, hybrid nanofluids consisting of nanoparticles of graphene and metals or carbides enhance the displacing ability. Using atomic force microscopy, scanning electron microscopy and molecular modelling methods, this work has studied the formation of supramolecular structures that form a transition region at the oil-nanofluid interface with low surface tension as a result of a synergistic effect in the interaction of graphene planar nanoparticles and silicon carbide nanoparticles covered with graphene layers (Core-shell). The model experiments on a Hele-Shaw cell have shown that in a porous medium, such hybrid nanofluids have a high displacement ability of residual oil. At the same time, the oil — nanofluid interface remains stable, without the formation of viscous fingers. During the study by scanning electron microscopy, a transition region was observed, in the structuring of which the nanoparticles were directly involved. The displacement efficiency of a hybrid nonofluid depends on the concentration of nanoparticles and their interaction.

Structural and electrical investigation of (Ag3AsS3)x(As2S3)1−x superionic glasses

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Ihor Studenyak ◽  
Yuriy Neimet ◽  
Csaba Cserháti ◽  
Sándor Kökényesi ◽  
Edvardas Kazakevičius ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Transmission Coefficient ◽  
Structural Studies ◽  
Compositional Range ◽  
Electrical Investigation ◽  
Scanning Electron

AbstractStructural studies of (Ag3AsS3)x (As2S3)1−x chalcogenide superionic glasses in the compositional range x = 0.3–0.9 were performed by scanning electron microscopy. Temperature and compositional dependences of transmission coefficient, electrical conductivity, and activation energy were investigated

Thermal Conductivity of Boron Carbides

1987 ◽  
Vol 97 ◽  
Author(s):  
Marvin Moss
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Temperature Dependence ◽  
Rutherford Backscattering ◽  
Rutherford Backscattering Spectroscopy ◽  
Theoretical Density ◽  
Increasing Temperature ◽  
Scanning Electron

ABSTRACTThe thermal conductivity, k, of boron carbides of various B/C ratios, two modes of preparation – hot pressed and carbothermic, and two isotopic variants of boron – 11B and normal boron 10.81B, was measured from 300 to 1023 K. The density and composition of the samples were reflected in the magnitude and temperature dependence of k, and were investigated further with scanning electron microscopy, Rutherford backscattering spectroscopy, and Raman spectroscopy. While lower than theoretical density in B4C reduces k, the characteristic monotonic decline of k with increasing temperature is retained. This k-vs.-T behavior distinguishes B4C from material with larger B/C ratios for which the temperature dependence is essentially nil.

Effect of Al2O3 on the Electrical Conductivity and Structural Study in MgI2-Mg3(PO4)2 Based Solid Electrolyte

2013 ◽  
Vol 701 ◽  
pp. 150-153
Author(s):  
A. Aziz ◽  
M.M. Mahat ◽  
A.H. Ahmad
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Impedance Spectroscopy ◽  
Field Emission ◽  
Weight Percent ◽  
Binary Compound ◽  
Maximum Conductivity ◽  
Enhanced Conductivity ◽  
Scanning Electron

The effect of filler to the binary compound of Magnesium Iodide ( MgI2) and Magnesium Phosphate (Mg3(PO4)2is investigated. A small amount Alumina (Al2O3) filler in the range of 2-10 weight percent is added to the optimum composition with maximum conductivity of binary compound 0.7 Mg3(PO4)2and 0.3 MgI2.The electrical conductivity of theMgI2- Mg3(PO4)2- Al2O3measured using the impedance spectroscopy (IS) method and result shows that the electrical conductivity of the compound has improved up to 9.84x10-4Scm-1. Field Emission Scanning Electron Microscopy (FESEM) images show some changes in the morphology after introduce the filler. The samples with filler showsnano flakes like structure with some space createdallowing the Mg2+cations to migrate that lead to enhanced conductivity.

Structural Properties of Sn-Doped ZnO Thin Films Deposited on Glass Substrate Using Sol-Gel Immersion Method

2015 ◽  
Vol 1109 ◽  
pp. 568-571
Author(s):  
Shafura Karim ◽  
Uzer Mohd Noor ◽  
M.H. Mamat ◽  
Shuhaimi Abu Bakar ◽  
Salman A.H. Alrokayan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Zinc Oxide ◽  
Glass Substrate ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Immersion Method ◽  
Doped Zno ◽  
Scanning Electron

Tin-doped Zinc Oxide (Sn-doped ZnO) thin films were prepared using zinc acetate dehydrate as a starting material by sol-gel immersion method. The doping concentrations were varied at 0 at.%, 1.0 at.%, 2.0 at.% and 3.0 at.%. The synthesized samples were characterized by Field Emission Scanning Electron Microscopy (FESEM).

Preparation of Polyaniline @ Polypyrrole Conductive Composite via In Situ Polymerization

2013 ◽  
Vol 562-565 ◽  
pp. 1137-1142
Author(s):  
Hui Xia Feng ◽  
Bing Wang ◽  
Lin Tan ◽  
Na Li Chen
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
In Situ Polymerization ◽  
Conductive Composite ◽  
The Core ◽  
Novel Method ◽  
Scanning Electron

We prepared the polyaniline@polypyrrole (PAn@PPy) conductive composite by a novel method. The struction like Pre-prepared PAn as the core and PPy as the shell for the composite has been prepared by in-situ polymerization. The PAn@PPy conductive composite presents an electrical conductivity of 12.5 S/cm, which is much higher than pure PAn. The synthesized polymer composites are characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermogravimetric analysis (TG). The results indicated that PPy successfully grafted on PAn and the heat resistance of nanocomposite is remarkably increased.

Tuning the Ablation, Thermal and Mechanical Characteristics of Phenolic Resin Reinforced EPDM Ultra-High Temperature Insulation

2021 ◽  
Vol 875 ◽  
pp. 88-95
Author(s):  
Sadia Sagar Iqbal ◽  
Tasawer Shahzad Ahmad ◽  
Arshad Bashir ◽  
Ali Bahadar ◽  
Farzana Siddique
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Scanning Electron Microscopy ◽  
Mechanical Characteristics ◽  
Phenolic Resin ◽  
Ethylene Propylene Diene Monomer ◽  
Polymer Melting ◽  
Base Matrix ◽  
Ablation Characteristics ◽  
Scanning Electron

The present research reports the influences of variant phenolic resin concentrations on the thermo-mechanical and ablation characteristics of ethylene propylene diene monomer (EPDM) elastomer. Backface temperature acclivity (BTA), charring rates, and insulation indexes were executed for the fabricated composite specimens. It was noticed that BTA was enhanced while linear/radial/mass ablation rates were significantly diminished with increasing concentration of phenolic resin (PR) in base matrix (elastomeric polymer). The composite (30wt%PR/EPDM) has 25% high thermal endurance compared to virgin EPDM composite. Thermal conductivity was increased with increasing PR to EPDM ratio. PR incorporation has remarkably enhanced the ultimate tensile strength of the EPDM elastomer. An efficient improvement in elastomeric hardness was also observed with increasing PR contents in EPDM matrix. Scanning Electron Microscopy (SEM) results showed the porosity generation and polymer melting during ablation.

scholarly journals Synthesis, Crystal Structure Refinement, and Electrical Conductivity of Pb(8−x)Na2Smx(VO4)6O(x/2)

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Tatiana M. Savankova ◽  
Lev G. Akselrud ◽  
Lyudmyla I. Ardanova ◽  
Alexey V. Ignatov ◽  
Eugeni I. Get’man ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Solid Solutions ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Solid solutions of Pb(8−x)Na2Smx(VO4)6O(x/2)were studied using X-ray diffraction analysis including Rietveld refinement and scanning electron microscopy and by measuring their electrical conductivity. Crystal structure of the solid solutions was refined and the solubility region0≤x≤0.2was determined for samarium substitution for lead under the scheme2Pb2++□→2Sm3++O2-. The influence of degree of substitution on the electrical conductivity of solid solutions was established.

Interfacial Examination of Cu/Al Joints Using Ultrafine Al-Si Powder as Brazing Filler Metal

2013 ◽  
Vol 829 ◽  
pp. 52-56
Author(s):  
Maryam Yarveicy ◽  
Ali Mohammad Hadian
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive Spectrometry ◽  
Filler Metal ◽  
Inert Atmosphere ◽  
Lower Weight ◽  
Prismatic Structure ◽  
Layer Region ◽  
Scanning Electron

Al-Cu joints have been widely used in electronic and heat exchanger industries due to their excellent electrical and thermal conductivity. Meanwhile, the use of Al in the Al-Cu joints can result in lower weight and cost of the final structure. The purpose of the current study is to join Al to Cu by furnace brazing using ultrafine Al-Si powder. To study the microstructure of the join area, the brazing tests were conducted in the range of 590 to 610°C for 5 to 15 minutes under inert atmosphere. The microstructure of Al/Cu joints was studied by scanning electron microscopy (SEM). The elemental analysis was conducted using an energy dispersive spectrometry (EDS) system. Experimental results show that two kinds of intermetallic compounds (IMCs) mainly Cu3Al2 and CuAl2 phases are formed near the interface of copper and in the braze layer region. The bulky prismatic structure which is formed on the side of Al substrate was found to be α-Al+CuAl2 eutectic.

Effect of the Consolidation Technique on the Sintering Ability and Thermal Properties of AlN Processed from Aqueous Suspensions

2006 ◽  
Vol 514-516 ◽  
pp. 1531-1535
Author(s):  
Susana M.H. Olhero ◽  
José Maria F. Ferreira
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Scanning Electron Microscopy ◽  
Slip Casting ◽  
Inert Atmosphere ◽  
Sintering Aids ◽  
X Ray ◽  
Aqueous Suspensions ◽  
Dry Pressing ◽  
Scanning Electron

In this work, two different consolidation techniques were used to obtain AlN samples: slip casting and dry pressing of granules obtained from aqueous suspensions by freeze granulation. The green samples were sintered at a temperature (1750°C) lower than those usually used (>1800°C), using CaF2 and YF3 as sintering aids. The microstructural features were analysed by scanning electron microscopy (SEM) and the crystalline phases formed were identified by X-ray (XRD). Full dense AlN-based ceramics were obtained from both consolidation techniques; however the thermal conductivity values were quite different. The presence of carbon in the samples derived from the freeze granulated powder containing organic processing additives de-waxed in an inert atmosphere revealed to be helpful in the cleaning of oxygen present at the grain boundaries and consequently, for enhancing the thermal conductivity.

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