A mathematical model of electric heating of the porous medium using current-supplying electrode/punches

Raichenko, A. I.; Chernikova, E. S.

doi:10.1007/bf00795038

Cited by 11 publications

(6 citation statements)

References 5 publications

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“…Because of the complex nature of various phenomena involved in SPS, only a relatively moderate number of modeling attempts have been undertaken until presently 1–56 . One of the most important questions: which factors provide accelerated densification and, in many cases, limited grain growth under SPS compared with regular hot pressing applied to the same material systems, still remains unanswered.…”

Section: Introductionmentioning

confidence: 99%

Impact of Thermal Diffusion on Densification During SPS

Olevsky

Froyen

2009

Journal of the American Ceramic Society

203

103

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Spark-plasma sintering (SPS) has the potential for rapid (with heating rates reaching several hundred K/min) and efficient consolidation of a broad spectrum of powder materials. Possible mechanisms of the enhancement of consolidation in SPS versus conventional techniques of powder processing are categorized with respect to their thermal and athermal nature. This paper analyzes the influence of thermal diffusion, which is an SPS consolidation enhancement factor of a thermal nature. The Ludwig-Soret effect of thermal diffusion causes concentration gradients in two-component systems subjected to a temperature gradient. The thermal diffusion-based constitutive mechanism of sintering results from the additional driving force instigated by spatial temperature gradients, which cause vacancy diffusion. This mechanism is a commonly omitted addition to the freesurface curvature-driven diffusion considered in conventional sintering theories. The interplay of three mechanisms of material transport during SPS is considered: surface tension-and external stress-driven grain-boundary diffusion, surface tensionand external stress-driven power-law creep, and temperature gradient-driven thermal diffusion. It is shown that the effect of thermal diffusion can be significant for ceramic powder systems. Besides SPS, the results obtained are applicable to the ample range of powder consolidation techniques, which involve high local temperature gradients.The case study conducted on the alumina powder SPS demonstrates the correlation between the modeling and experimental data. It is noted that this study considers only one of many possible mechanisms of the consolidation enhancement during SPS. Further efforts on the modeling of field-assisted powder processing are necessary.

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Section: Introductionmentioning

confidence: 99%

Impact of Thermal Diffusion on Densification During SPS

Olevsky

Froyen

2009

Journal of the American Ceramic Society

203

103

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“…Spatial and temporal inhomogeneities on micro- and macroscales are characteristics of the physical processes occurring during sintering of materials by means of electric current. The most widely considered problems in the theoretical studies, as can be concluded on the basis of this review, are those directed at finding the general laws, the temperature distribution fields [ 27 , 119 , 134 , 135 , 136 ], electrical resistance of the sintered material as well as current density and voltage [ 14 , 15 , 37 , 39 , 46 , 137 ]. Several studies have been concerned with the solution of the thermo-electric problem [ 10 , 33 , 138 ].…”

Section: Modeling Of Electric Current-assisted Consolidation Of Pomentioning

confidence: 99%

“…The current density was determined by the quasi-steady-state equation of current flow taking into account the dependence of the resistivity on temperature. In Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Raichenko et al [ 134 , 135 , 139 ] considered a similar problem and studied the influence of electric current on the processes at the interface between the powder compact and the punch. Denoting the temperature of the powder compact as T 1 and the temperature of the punches as T 2 , a system of equations can be composed (1), which determines the temperature distribution in the sample ( i = 1) and punches ( i = 2) along the vertical Z-axis.…”

Section: Modeling Of Electric Current-assisted Consolidation Of Pomentioning

confidence: 99%

Outside Mainstream Electronic Databases: Review of Studies Conducted in the USSR and Post-Soviet Countries on Electric Current-Assisted Consolidation of Powder Materials

et al. 2013

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This paper reviews research articles published in the former USSR and post-soviet countries on the consolidation of powder materials using electric current that passes through the powder sample and/or a conductive die-punch set-up. Having been published in Russian, many of the reviewed papers are not included in the mainstream electronic databases of the scientific articles and thus are not known to the scientific community. The present review is aimed at filling this information gap. In the paper, the electric current-assisted sintering techniques based on high- and low-voltage approaches are presented. The main results of the theoretical modeling of the processes of electromagnetic field-assisted consolidation of powder materials are discussed. Sintering experiments and related equipment are described and the major experimental results are analyzed. Sintering conditions required to achieve the desired properties of the sintered materials are provided for selected material systems. Tooling materials used in the electric current-assisted consolidation set-ups are also described.

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“…New techniques are constantly emerging in an attempt to overcome the shortcomings of conventional processing. The direct use of electricity as a means to sinter powders has been suggested numerous times and with different approaches [3][4][5][6][7][8][9][10][11]. One of these techniques is electrical resistance sintering (ERS), in which heating is achieved by passing an electrical current through the powders.…”

Section: Introductionmentioning

confidence: 99%

Production of Ultrafine Grained Hardmetals by Electrical Resistance Sintering

Cintas

Astacio

Cuevas

et al. 2019

Metals

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In this work, powders of cemented ultrafine WC-6 wt.% Co were consolidated. The feasibility of the medium frequency electrical resistance sintering (MF-ERS) technique were studied to prevent WC grain growth during consolidation. Porosity and hardness were measured at different zones of the MF-ERS compacts. The compacts showed a slight inhomogeneity in their properties across their section, but it was controlled by choosing suitable values of the processing parameters. The optimal values for the material studied were current intensities between 7 and 8 kA and sintering times between 600 and 800 ms. The main achievement using this consolidation method was that sintered compacts essentially maintained the initial WC grain size. This was attained to processing times of less than 2 s, and without the need for using protective atmospheres.

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A mathematical model of electric heating of the porous medium using current-supplying electrode/punches

Cited by 11 publications

References 5 publications

Impact of Thermal Diffusion on Densification During SPS

Impact of Thermal Diffusion on Densification During SPS

Outside Mainstream Electronic Databases: Review of Studies Conducted in the USSR and Post-Soviet Countries on Electric Current-Assisted Consolidation of Powder Materials

Production of Ultrafine Grained Hardmetals by Electrical Resistance Sintering

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