Observation of internal pulsed current flow through the ZnO specimen in the spark plasma sintering method

Misawa, Tatsuya; Shikatani, Noboru; Kawakami, Yuji; Enjoji, Takashi; Ohtsu, Yasunori; Fujita, Hiroharu

doi:10.1007/s10853-008-2906-5

Cited by 37 publications

(27 citation statements)

References 8 publications

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“…In many cases there is little difference between hot pressing (where heat is supplied by an induction furnace rather than electric current through the die) and spark plasma sintering [66], with the advantages of the later chiefly originating from superior heating rates and higher applied pressures [1]. The exception is where materials have significant electrical conductivity, such as doped zinc oxide, where current-induced microstructural features can be observed [67].…”

Section: Comparison To Other Non-conventional Ceramic Firing Techniquesmentioning

confidence: 99%

Flash sintering of ceramic materials

Dancer¹

2016

Mater. Res. Express

155

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During flash sintering, ceramic materials can sinter to high density in a matter of seconds while subjected to electric field and elevated temperature. This process, which occurs at lower furnace temperatures and in shorter times than both conventional ceramic sintering and field-assisted methods such as spark plasma sintering, has the potential to radically reduce the power consumption required for the densification of ceramic materials. This paper reviews the experimental work on flash sintering methods carried out to date, and compares the properties of the materials obtained to those produced by conventional sintering. The flash sintering process is described for oxides of zirconium, yttrium, aluminium, tin, zinc, and titanium; silicon and boron carbide, zirconium diboride, materials for solid oxide fuel applications, ferroelectric materials, and composite materials. While experimental observations have been made on a wide range of materials, understanding of the underlying mechanisms responsible for the onset and latter stages of flash sintering is still elusive. Elements of the proposed theories to explain the observed behaviour include extensive Joule heating throughout the material causing thermal runaway, arrested by the current limitation in the power supply, and the formation of defect avalanches which rapidly and dramatically increase the sample conductivity.Undoubtedly, the flash sintering process is affected by the electric field strength, furnace temperature and current density limit, but also by microstructural features such as the presence of second phase particles or dopants and the particle size in the starting material. While further experimental work and modelling is still required to attain a full understanding capable of predicting the success of the flash sintering process in different materials, the technique nonetheless holds great potential for exceptional control of the ceramic sintering process.

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Section: Comparison To Other Non-conventional Ceramic Firing Techniquesmentioning

confidence: 99%

Flash sintering of ceramic materials

Dancer¹

2016

Mater. Res. Express

155

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“…Thus, also configuration B is not suitable for investigating the intrinsic effect of the electric current during SPS. In particular, the recent study by Misawa et al [6], which compared results obtained using arrangements A (equipped with a graphite die instead of an alumina die) and B, might be inconclusive.…”

Section: Modeling Results and Discussionmentioning

confidence: 98%

“…To the best of our knowledge, only one attempt to directly measure the current through a specimen during SPS has been reported to date [6]. However, several limitations and difficulties occurred during the measurement, casting doubt on the reliability of this technique.…”

Section: Introductionmentioning

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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“…There are dark-grey-dark regions (q 5 q 4 q 3 in Fig. 6b) present around large Al-Cr-Fe particles, which are identified as TiAl, Cr 2 Ti and L1 2 [with a composition of Al-25?8Ti-6?1Cr-8?4Fe (at-%)] by EDX analysis and phase diagram analysis 21,22 while only TiAl regions were found around small Al-Cr-Fe particles. During the initial stage of sintering, plasma in the small gaps between particles can bring about evaporation and melting of the surfaces of these powders.…”

Section: Resultsmentioning

confidence: 99%

Novel Ti based metal matrix composites reinforced with Al–Cr–Fe quasicrystals approximants

Dong

Khun

et al. 2015

Materials Science and Technology

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In this work, Ti/Al-Cr-Fe metal matrix composites were fabricated with Ti as matrix and Al-Cr-Fe quasicrystal approximants as reinforcements using spark plasma sintering. In all samples a Ti 3 Al ring forms around each Al-Cr-Fe particle as a bonding layer between Ti and Al-Cr-Fe particles. In the sample sintered with a holding time of 5 min, there are only TiAl regions present at the Ti 3 Al/ Al-Cr-Fe interface. However, in the samples sintered with a holding time of 10, 15 or 20 min, TiAl, Ti(Al,Cr) 2 and L1 2 regions were detected at the Ti 3 Al/Al-Cr-Fe interface. The addition of Al-Cr-Fe particles into the Ti matrix was found to improve the mircrohardness to 460 HV and increase the wear resistance by more than 50%.

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Observation of internal pulsed current flow through the ZnO specimen in the spark plasma sintering method

Cited by 37 publications

References 8 publications

Flash sintering of ceramic materials

Flash sintering of ceramic materials

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

Novel Ti based metal matrix composites reinforced with Al–Cr–Fe quasicrystals approximants

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