The electrical conductance growth of a metallic granular packing

Jakšić, Z. M.; Cvetković, Milica; Šćepanović, J. R.; Lončarević, Ivana; Budinski-Petkovic, Ljuba; Vrhovac, S. B.

doi:10.1140/epjb/e2017-70597-6

Cited by 4 publications

(5 citation statements)

References 33 publications

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“…According to our results, the distribution of grains does not change the behavior of resistance, it decreases with time whatever the packing. According to Jakšić et al [10], granular packings of low-carbon steel cylinders display the same decrease in resistance during the first 3000 s for the current 𝐼 = 1 mA which is attributed to the improvement of microcontacts between the grains. To investigate the influence of current interruptions on a temporal decrease of resistance of a particular packing, we performed a certain number of measurements in which the current was interrupted three times for 5s during the first stages of the evolution.…”

Section: Resultsmentioning

confidence: 89%

“…Because of that, the chemically etched inox beads were used. According to [10], when two beads are brought into contact, the surface irregularities create a large number of conducting microchannels. Two approaches were used during the measurements: the same packing of the beads was used for different current intensities and a new packing of the beads was formed each time the value of the current was changed.…”

Section: Resultsmentioning

confidence: 99%

“…Temporal evolution of resistance R(t) in metallic granular packings when a stable current through the system is injected can be found only in a few papers [2,[10][11][12]. The decrease in resistance is considered to be the result of improved microcontacts [13] between the granules due to their local welding.…”

Section: Introductionmentioning

confidence: 99%

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Electrical resistance through the metallic granular packings

Dujak

Đekić²,

Ćubela

2022

J. Phys.: Conf. Ser.

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The resistance drop with time in metallic granular materials has been the subject of research since the 19th century, but it is still not fully clarified. The wider application of granular materials in the industry has contributed to the increased interest in this phenomenon. The key parameters that are mainly examined are as follows: the influence of different packings, dimensions, and shapes of the granules, as well as the influence of the pressure, exerted on them. However, there is a limited number of papers that examine the temporal evolution of the resistance in these materials. In this report, we investigate how different packings of two-dimensional stainless steel beads (inox) as well as different currents injected into them affect the temporal evolution of resistance. We also examine the effect of the breaks in the current flow for the current varied between 0.2 and 8 mA for both inox beads as well as low-carbon steel cylinders. The results show the drop of resistance over time for all current values, which is more pronounced in earlier stages of the time evolution. Interruptions in current flow cause an immediate decrease of resistance in both materials.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

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Electrical resistance through the metallic granular packings

Dujak

Đekić²,

Ćubela

2022

J. Phys.: Conf. Ser.

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“…Recently, several experimental studies have been performed on the electrical properties of packing of metallic disks [57][58][59]. Their voltage-current characteristics present a static bearing and describe a hysteresis.…”

Section: Introductionmentioning

confidence: 99%

“…Their voltage-current characteristics present a static bearing and describe a hysteresis. Zorica et al [59] suggested that electro-mechanical processes allow both the creation and breakdown of microcontacts between two stacked disks. According to them, the current would flow through contact spots related to the roughness of facing surfaces.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Electrical Transitions in the First Steps of Spark Plasma Sintering: Effects of Pre-Oxidation and Mechanical Loading within Copper Granular Media

et al. 2022

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Spark Plasma Sintering (SPS) has become a conventional and promising sintering method for powder consolidation. This study aims to well understand the mechanisms of densification encountered during SPS treatments, especially in the early stages of sintering. The direct current (DC) electrical behavior of copper granular medium is characterized. Their properties are correlated with their microstructural evolutions through post-mortem scanning electron microscope (SEM) observations to allow a thorough understanding of the involved Branly effect that is suspected to occur in SPS. The electrical response is studied by modifying the initial thickness of the oxide layer on particles surfaces and applying various mechanical loads on the granular medium. Without load and at low current, the measured quasi-reversible behavior is connected to the formation of spots at the microcontacts between the particles. By increasing the current, the Branly transition from an insulating to a conductive state suddenly occurs. The insulating oxide layer is destroyed, and micro-bridges are created. The application of a mechanical pressure strongly modifies the DC Branly effect. Increasing low stress leads to a strong decrease in the breakdown field. For high-applied pressure, successive drops in the electric field are detected during the electrical transition. These successive drops are induced by microcracking of the insulating oxide layer.

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