Electrical resistivity behaviour of Ag-Ge-Te glasses under pressure at different temperatures: the influence of bonding and topological thresholds

1999 ◽  
Vol 11 (19) ◽  
pp. 3897-3906 ◽  
Author(s):  
K Ramesh ◽  
S Asokan ◽  
K S Sangunni ◽  
E S R Gopal
Keyword(s):  
Electrical Resistivity ◽  
Different Temperatures ◽  
Resistivity Behaviour

Preparation and Characterization of NTC NiMn2O4-La1-xCaxMnO3 (0≤x≤0.3) Composite Ceramics

2013 ◽  
Vol 716 ◽  
pp. 78-83 ◽  
Author(s):  
Hui Min Zhang ◽  
Fang Guan ◽  
Ai Min Chang ◽  
Li Jun Zhao
Keyword(s):  
Electrical Resistivity ◽  
Perovskite Structure ◽  
Spinel Structure ◽  
Thermal Constant ◽  
Inrush Current ◽  
Composite Ceramics ◽  
Sem Images ◽  
Conventional Solid State Reaction ◽  
Different Temperatures ◽  
Xrd Patterns

Composite ceramics made of spinel structure NiMn2O4 and CaO-doped perovskite structure LaMnO3 were prepared by a conventional solid state reaction and sintered at different temperatures. The XRD patterns have shown that the major phases presented in the sintered samples are NiMn2O4 compounds with the spinel structure, La1-xCaxMnO3 with the perovskite structure and NiO with a monoclinic structure. SEM images show that the density and grain size of the composite ceramics increases with sintered temperature increasing. The electrical resistivity of the composite ceramics at 25°C is found to change significantly depending on the CaO content, while the thermal constant B is still reasonably large in the range of 2400 to 3000 K. For the composition x = 0.1, the composite with a low electrical resistivity (ρ25°C=4.46Ω·cm) and moderate B value (B25/50=2762K) was obtained. These composites could be applied as potential candidates for NTC thermistors in the suppression of the inrush current.

Characteristics of FeCuAl Powder Compacts Formed through Uniaxial Die Compaction Route

2017 ◽  
Vol 264 ◽  
pp. 103-106 ◽  
Author(s):  
M.M. Rahman ◽  
M.A. Ismail ◽  
H. Y. Rahman
Keyword(s):  
Electrical Resistivity ◽  
Relative Density ◽  
Bending Strength ◽  
Axial Loading ◽  
Homogeneous Distribution ◽  
Volumetric Expansion ◽  
Different Temperatures ◽  
Die Compaction ◽  
Powder Compacts ◽  
Interconnected Pores

This paper presents the development of FeCuAl powder compacts through uniaxial die compaction process. Iron powder ASC 100.29 was mechanically mixed with other elemental powders, i.e., copper (Cu), and aluminum (Al) for 30 minutes at a rotation of 30 rpm. The feedstock was subsequently shaped at three different temperatures, i.e., 30°C, 150°C, and 200°C through simultaneous upward and downward axial loading of 325 MPa. The as-pressed samples termed as green compacts were then sintered in argon gas fired furnace at 800°C for three different holding times, i.e., 30, 60, and 90 min at a rate of 10°C/min. The sintered samples were characterized for their relative density, electrical resistivity, and bending strength. The microstructure of the sintered samples was also evaluated through scanning electron microscopy (SEM). The results revealed that the sample formed at 150°C and sintered for 30 min obtained the best final characteristics, i.e., higher relative density, lower volumetric expansion and electrical resistivity, and higher bending strength. Microstructure evaluation also revealed that the sample formed at 150°C and sintered for 30 min obtained more homogeneous distribution of grains and less interconnected pores compared to the other samples.

On the curious electrical resistivity behaviour of Al86Mn14 quasicrystalline phase

1987 ◽  
Vol 64 (11) ◽  
pp. 1409-1412 ◽  
Author(s):  
N.P. Lalla ◽  
A.K. Singh ◽  
R.S. Tiwari ◽  
O.N. Srivastava
Keyword(s):  
Electrical Resistivity ◽  
Quasicrystalline Phase ◽  
Resistivity Behaviour

scholarly journals Existence of Partially Degenerate Electrical Transport in Intermetallic Cu2SnSe3 Thermoelectric System Sintered at Different Temperatures

2021 ◽  
Author(s):  
K. Gurukrishna ◽  
H. R. Nikhita ◽  
S. M. Mallikarjuna Swamy ◽  
Ashok Rao
Keyword(s):  
Electrical Resistivity ◽  
High Temperatures ◽  
Electrical Transport ◽  
Minority Carrier ◽  
Upward Movement ◽  
Temperature Dependent ◽  
Conventional Solid State Reaction ◽  
Different Temperatures ◽  
Transport Behaviour ◽  
Small Polarons

AbstractA detailed investigation on the temperature dependent electrical properties of Cu2SnSe3 system, synthesized via conventional solid-state reaction at different sintering temperatures are presented in this communication. All the samples exhibit degenerate semiconducting nature at low temperatures. The existence of small polarons and hence electron–phonon interactions are confirmed at temperatures below 400 K. A transition was observed from degenerate to non-degenerate semiconducting behaviour at high temperatures (T > 400 K). The study confirms the unusual transition in electrical resistivity as well as thermopower at high temperatures in all the compounds, demonstrating the existence of minority carrier excitation along with temperature-triggered ionisation of the defects. The transport behaviour is further supported by an upward movement of Fermi level away from the valence band. Highest weighted mobility of 8.2 cm2 V−1 s−1 at 673 K was obtained for the sample sintered at 1073 K. A considerable decrease in electrical resistivity with increase in temperature (T > 400 K) has driven the power factor to increase exponentially, thereby achieving highest value of 188 µV/mK2 (at 673 K) for the sample sintered at 673 K. Graphic abstract

Molten Aluminum: Inductive Technique for Electrical Conductivity Measurements

2019 ◽  
Author(s):  
Sayavur Bakhtiyarov ◽  
Ruel Overfelt
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Aluminum Alloy ◽  
Measurement Technique ◽  
Molten Aluminum ◽  
Energy Losses ◽  
Additional Energy ◽  
Different Temperatures ◽  
Inductive Measurement ◽  
Contact Surfaces

A rotational, contactless inductive measurement technique has been used to determine the effect of pores and metallic insertions on the electrical resistivity of A2011 aluminum alloy at different temperatures. It is shown that the electrical resistivity increases with the total volume of pores and is also dependent on the pores locations and orientation. Additional energy losses were found on the contact surfaces between sample and insertions.

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