Electrical Resistivity of Metal Powder Aggregates

Montes, J. M.; Cuevas, F. G.; Cintas, J.

doi:10.1007/s11663-007-9097-3

Cited by 33 publications

(18 citation statements)

References 12 publications

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“…Deformation and/or sliding breaks up the oxide layer and creates new metallic contacts between the particles. 13) As a conclusion, contact force, as well as heat bonding and electromigration, is believed to be the important driving force for the resistance drop under ECAS condition. Moreover, the effects of all these potential mechanisms on resistance drop are strongly dependent on the bulk temperature of the compact.…”

Section: Examination Of Electrical Conduction Of Carbonyl Iron Powdermentioning

confidence: 93%

“…Electric current activated sintering (ECAS) of metal materials is based on the flow of electric current through the compact, but the sintering behavior remains unclear. 13) Generally, a measurement of sintering temperature is a useful way to help discriminate the main mechanism for sintering, and allow for proper comparison with other sintering techniques. 4) However, it remains a great challenge to determine the true temperature in the particles and at the particle contacts during ECAS.…”

Section: Introductionmentioning

confidence: 99%

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Examination of Electrical Conduction of Carbonyl Iron Powder Compacts

Zheng

et al. 2015

Mater. Trans.

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In this study, we report the electrical conduction of carbonyl iron powder compacts when a constant voltage/current source is supplied, especially under a typical voltage 9.7 V of electric current activated sintering (ECAS). The potential driving forces for resistance drop during stressing, including bulk temperature-dependent and -independent, were discussed. By using a proposed competition mechanism and percolation theory, it can successfully describe electrical behavior in metal powder compacts. The results indicate bulk temperature rise resulting from Joule heating is the main cause for the formation and growth of metallic contact at particle interfaces during ECAS.

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Section: Examination Of Electrical Conduction Of Carbonyl Iron Powdermentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Examination of Electrical Conduction of Carbonyl Iron Powder Compacts

Zheng

et al. 2015

Mater. Trans.

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“…The electrical resistivity of these oxides (with dielectric or semiconductor character), in general, decays in an exponential way with temperature. This can suppose an electrical resistivity decrease of several orders (for example, the Fe 2 O 3 has a resistivity of 10 16 Ωm at room temperature, decreasing to 10 −2 Ωm at 1000 K) [14,15]. Regardless of whether or not the oxide layer is sufficiently thin, the whole particle is affected by the layer resistivity [16,17].…”

Section: A Qualitative Model For Densificationmentioning

confidence: 99%

Medium-Frequency Electrical Resistance Sintering of Oxidized C.P. Iron Powder

Montes

Cuevas

Fernández

et al. 2018

Metals

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Commercially pure (C.P.) iron powders with a deliberate high degree of oxidation were consolidated by medium-frequency electrical resistance sintering (MF-ERS). This is a consolidation technique where pressure, and heat coming from a low-voltage and high-intensity electrical current, are simultaneously applied to a powder mass. In this work, the achieved densification rate is interpreted according to a qualitative microscopic model, based on the compacts global porosity and electrical resistance evolution. The effect of current intensity and sintering time on compacts was studied on the basis of micrographs revealing the porosity distribution inside the sintered compact. The microstructural characteristics of compacts consolidated by the traditional cold-press and furnace-sinter powder metallurgy route are compared with results of MF-ERS consolidation. The goodness of MF-ERS versus the problems of conventional sintering when working with oxidized powders is analyzed. The electrical consolidation can obtain higher densifications than the traditional route under non-reducing atmospheres.

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“…In this work, the measured variable is represented by the temperature of the powder sample determined as shown in figure 1. The electric resistivity and thermal conductivity of the powder compact are evaluated using equations available in the literature [11]. Computational details of the numerical solution of the above differential, algebraic and integral equations can be found elsewhere [7].…”

Section: Modeling Sectionmentioning

confidence: 99%

A methodology to investigate the intrinsic effect of the pulsed electric current during the spark plasma sintering of electrically conductive powders

Locci

Cincotti

Todde

et al. 2010

Science and Technology of Advanced Materials

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Cao (2010) A methodology to investigate the intrinsic effect of the pulsed electric current during the spark plasma sintering of electrically conductive powders, Science Abstract A novel methodology is proposed for investigating the effect of the pulsed electric current during the spark plasma sintering (SPS) of electrically conductive powders without potential misinterpretation of experimental results. First, ensemble configurations (geometry, size and material of the powder sample, die, plunger and spacers) are identified where the electric current is forced to flow only through either the sample or the die, so that the sample is heated either through the Joule effect or by thermal conduction, respectively. These ensemble configurations are selected using a recently proposed mathematical model of an SPS apparatus, which, once suitably modified, makes it possible to carry out detailed electrical and thermal analysis. Next, SPS experiments are conducted using the ensemble configurations theoretically identified. Using aluminum powders as a case study, we find that the temporal profiles of sample shrinkage, which indicate densification behavior, as well as the final density of the sample are clearly different when the electric current flows only through the sample or through the die containing it, whereas the temperature cycle and mechanical load are the same in both cases.Keywords:electriccurrent,Jouleeffect,modeling,sparkplasmasintering

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Electrical Resistivity of Metal Powder Aggregates

Cited by 33 publications

References 12 publications

Examination of Electrical Conduction of Carbonyl Iron Powder Compacts

Examination of Electrical Conduction of Carbonyl Iron Powder Compacts

Medium-Frequency Electrical Resistance Sintering of Oxidized C.P. Iron Powder

A methodology to investigate the intrinsic effect of the pulsed electric current during the spark plasma sintering of electrically conductive powders

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