From conventional ac flash-sintering of YSZ to hyper-flash and double flash

Steil, M.C.; Marinha, Daniel; Aman, Yann; Gomes, Jonas R.C.; Kleitz, M.

doi:10.1016/j.jeurceramsoc.2013.03.019

Cited by 100 publications

(74 citation statements)

References 13 publications

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“…A modulated FS technique called hyper flash was developed by Steil et al [57] In the initial stage, 2000 mW mm −3 of power was applied for several seconds to sinter 8YSZ up to 88% TD with limited grain growth. Subsequent FS at higher power resulted in a more controlled and complete densification [57].…”

Section: Fs Of Ionic Conductorsmentioning

confidence: 99%

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Review of flash sintering: materials, mechanisms and modelling

Grasso

McKinnon

et al. 2016

Advances in Applied Ceramics

376

248

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Flash sintering (FS) is an energy efficient sintering technique involving electrical Joule heating, which allows very rapid densification (<60 s) of particulate materials. Since the first publication on flash-sintered zirconia (3YSZ) in 2010, it has been intensively researched and applied to a wide range of materials. Going back more than a century ago, we have found a close similarity between FS of oxides and Nernst glowers developed in 1897. This review provides a comprehensive overview of FS and is based on a literature survey consisting of 88 papers and seven patents. It correlates processing parameters (i.e. electric field magnitude, current density, waveforms (AC, DC) and frequency, furnace temperature, electrode materials/ configuration, externally applied pressure and sintering atmosphere) with microstructures and densification mechanisms. Theorised mechanisms driving the rapid densification are substantiated by modelling work, advanced in situ analysis techniques and by established theories applied to electric current assisted/activated sintering techniques. The possibility of applying FS to a wider range of materials and its implementation in industrial scale processes are discussed.

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Section: Fs Of Ionic Conductorsmentioning

confidence: 99%

“…Subsequent FS at higher power resulted in a more controlled and complete densification [57]. Using a commercial SPS machine, Vasylkiv et al [46] demonstrated the feasibility of FSPS (20 mm disc shaped samples) using 3YSZ nanoparticles under a voltage as low as 10 V (estimated field ≈2 V cm…”

Section: Fs Of Ionic Conductorsmentioning

confidence: 99%

Review of flash sintering: materials, mechanisms and modelling

Grasso

McKinnon

et al. 2016

Advances in Applied Ceramics

376

248

View full text Add to dashboard Cite

show abstract

“…Both dogbone shaped samples [4] and pellets [25] have been successfully flash sintered, using both Pt wire electrodes to suspend the dogbones [4,21] and the Pt discs/grids or paint electrodes for pellets [24,25,38,47,78,79].…”

Section: Zirconiamentioning

confidence: 99%

“…A variety of experimental apparatus setups have been used, including the vertical tube furnace with suspended dogbone construction [4,21], an adapted dilatometer [38,47,78], a standard tube furnace [24], a split vertical furnace mounted in a mechanical testing machine [25], and a custom-built vertical arrangement with pellet shaped samples, with the ability to add load [79]. Both DC [21] and AC [38] conditions have been used for densification.…”

Section: Zirconiamentioning

confidence: 99%

Flash sintering of ceramic materials

Dancer¹

2016

Mater. Res. Express

150

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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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“…The electric field-assisted pressureless sintering technique has mainly been applied to yttria-stabilized zirconia ceramics [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Many other reports were published applying this technique to other materials [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], studying the dependence on the amplitudes of the electric field and current density [31], on the average particle size [32], on the porosity [33], and searching for an explanation of such events [34][35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Electrical Behavior and Microstructural Features of Electric Field-Assisted and Conventionally Sintered 3 mol% Yttria-Stabilized Zirconia

Carvalho¹,

Muccillo²,

Muccillo

2018

Ceramics

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ZrO 2 : 3 mol % Y 2 O 3 (3YSZ) polycrystalline pellets were sintered at 1400 • C and by applying an alternating current (AC) electric field at 1000 • C. An alumina sample holder with platinum wires for connecting the sample to a power supply was designed for the electric field-assisted sintering experiments. The apparent density was evaluated with the Archimedes technique, the grain size distribution by analysis of scanning electron microscopy images, and the electrical behavior by the impedance spectroscopy technique. Sintering with the application of AC electric fields to 3YSZ enhances its ionic conductivity. An explanation is proposed, based on the dissolution back to the bulk of chemical species, which are depleted at the grain boundaries, leading to an increase in the oxygen vacancy concentration. For the enhancement of the grain boundary conductivity, an explanation is given based on the diminution of the concentration of depleted chemical species, which migrate to the bulk. This migration leads to a decrease of the potential barrier of the space charge region, known to be responsible for blocking the oxide ions through the intergranular region. Moreover, the heterogeneity of the distribution of the grain sizes is ascribed to the skin effect, the tendency of the AC current density to be largest near the surface, decreasing towards the bulk.

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From conventional ac flash-sintering of YSZ to hyper-flash and double flash

Cited by 100 publications

References 13 publications

Review of flash sintering: materials, mechanisms and modelling

Review of flash sintering: materials, mechanisms and modelling

Flash sintering of ceramic materials

Electrical Behavior and Microstructural Features of Electric Field-Assisted and Conventionally Sintered 3 mol% Yttria-Stabilized Zirconia

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