Electrical Resistivity Evolution and Brittle Failure of Sandstone After Exposure to Different Temperatures

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.

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Characteristics of FeCuAl Powder Compacts Formed through Uniaxial Die Compaction Route

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.264.103 ◽

2017 ◽

Vol 264 ◽

pp. 103-106 ◽

Cited By ~ 1

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.

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

Metals and Materials International ◽

10.1007/s12540-021-01074-8 ◽

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

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Molten Aluminum: Inductive Technique for Electrical Conductivity Measurements

Encyclopedia of Aluminum and Its Alloys ◽

10.1201/9781351045636-140000326 ◽

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

Journal of Physics Condensed Matter ◽

10.1088/0953-8984/11/19/309 ◽

1999 ◽

Vol 11 (19) ◽

pp. 3897-3906 ◽

Cited By ~ 8

Author(s):

K Ramesh ◽

S Asokan ◽

K S Sangunni ◽

E S R Gopal

Keyword(s):

Electrical Resistivity ◽

Different Temperatures ◽

Resistivity Behaviour

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Electrical Conductivity of Aluminum Alloy A2011

Encyclopedia of Aluminum and Its Alloys ◽

10.1201/9781351045636-140000251 ◽

2019 ◽

Author(s):

Sayavur Bakhtiyarov ◽

Ruel Overfelt

Keyword(s):

Electrical Conductivity ◽

Electrical Resistivity ◽

Aluminum Alloy ◽

Measurement Technique ◽

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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The Electrical Resistivity of B4C Modified Phenol-Formaldehyde Resin Matrix Composite Materials Pyrolyzed at Different Temperatures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.583.36 ◽

2012 ◽

Vol 583 ◽

pp. 36-39 ◽

Cited By ~ 1

Author(s):

Hai Yun Jiang ◽

Ji Gang Wang ◽

Shen Qing Wu ◽

Wei Li Zhang

Keyword(s):

Electrical Resistivity ◽

Phenol Formaldehyde ◽

Phenol Formaldehyde Resin ◽

Resin Matrix ◽

Formaldehyde Resin ◽

X Ray Diffraction ◽

X Ray ◽

Heat Treated ◽

Different Temperatures ◽

Resin Matrix Composite

The electrical resistivity is studied when B4C modified phenol-formaldehyde (PF) resin is heat-treated at temperatures of 300-1500 °C, and then the X-ray diffraction (XRD) spectra are also investigated. The results indicate that the electrical resistivity is elevated with the increase of pyrolytic temperature of PF resin. The addition of B4C decreases the electrical resistivity efficiently when the temperature is range of 700-1000 °C. Especially the composite is treated at tmperatures of 1000-1500 °C. The analysis of XRD spectra suggests that the addition of B4C promotes the arrangement of residue at high temperature. The arrangement reaction has not a direct effect on the electrical resistivity.

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Factors Affecting the Mechanical Properties of Cu/Electroless Ni-P/Sn-3.5Ag Solder Joints

MRS Proceedings ◽

10.1557/proc-0968-v04-04 ◽

2006 ◽

Vol 968 ◽

Cited By ~ 1

Author(s):

Aditya Kumar ◽

Zhong Chen ◽

C. C. Wong ◽

S. G. Mhaisalkar ◽

Vaidhyanathan Kripesh

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Solid State ◽

Brittle Failure ◽

Solder Joints ◽

Factors Affecting ◽

Intermetallic Particles ◽

Different Temperatures ◽

Kirkendall Voids ◽

Electroless Ni

ABSTRACTThis work investigates the factors that affect the mechanical properties of Cu/electroless Ni-P/Sn-3.5Ag solder joints. For the investigation, solder joints were tensile tested after solid-state aging at different temperatures for various durations. Several factors, such as the growth of interfacial compounds (IFCs), Ni3Sn4 morphology, the accumulation of spalled Ni3Sn4 intermetallic particles at the solder/Ni3Sn4 interface, and the formation of Kirkendall voids at the Ni3P/Cu interface, are found to deteriorate the mechanical properties of the joints. Among all these factors, the formation of a layer of Kirkendall voids at the Ni3P/Cu interface, which is a result of Cu diffusion from the interface, causes the most severe decrease in tensile strength with a brittle fracture at the Ni3P/Cu interface. This layer of Kirkendall voids remains the main cause of brittle failure even after the transformation of the Ni3P layer into a Ni-Sn-P layer.

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Phase Transformations in Amorphous Bilayer Ribbons

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.172-174.953 ◽

2011 ◽

Vol 172-174 ◽

pp. 953-958 ◽

Cited By ~ 6

Author(s):

Peter Svec ◽

Peter Svec Sr. ◽

Igor Matko ◽

Ivan Skorvánek ◽

Jozef Kováč ◽

...

Keyword(s):

Electrical Resistivity ◽

Phase Transformations ◽

Amorphous State ◽

Single Layer ◽

Amorphous Structure ◽

Rapid Quenching ◽

Layer Interface ◽

Different Temperatures

Bilayer ribbons were prepared by rapid quenching from the melt using a double-nozzle technique. The composition of the layers was selected from the Fe/Co-Si-B and Fe-Cu-Nb-Si-B systems, respectively. Ribbons with typical thickness of 45-50 microns and width of 6 mm and 10 mm exhibited amorphous structure of both layers in as-quenched state. Temperature dependencies of electrical resistivity, dilatation and magnetization have been investigated in the amorphous state and during crystallization of both layers, which take place at different temperatures. The results combined with investigation of the structures formed in each layer and at the layer interface were compared to those of single-layer ribbons having the compositions of each layer, respectively.

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