A simple flash sintering setup under applied mechanical stress and controlled atmosphere

Caliman, Lorena Batista; Bichaud, Emmanuelle; Soudant, Priscillia; Gouvêa, Douglas; Steil, M.C.

doi:10.1016/j.mex.2015.10.004

Cited by 20 publications

(20 citation statements)

References 12 publications

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“…The second approach uses an adapted dilatometer [24] or mechanical loading frame [25], or similar home-built devices [26]. In this case some degree of loading is required to keep the sample in place, though generally in these setups the applied uniaxial force has been kept very low.…”

Section: Flash Sintering Apparatusmentioning

confidence: 99%

“…Dogbone-shaped specimens are convenient for the monitoring of shrinkage in the gauge section during the flash sintering process by visual methods [39], whereas shrinkage in pellets is usually measured using linear displacement techniques such as the use of a force sensor [26] or laser system [40]. There is evidence that the handle-sections of flash-sintered dogbone specimens experience higher electric fields and hence higher temperatures, leading to larger grain growth under DC electric fields [41].…”

Section: Specimen Geometrymentioning

confidence: 99%

“…Samples have been flash sintered in dogbone [8,20,22,23,39,41,[71][72][73] and pellet form [26,31,36,37]. The apparatus used includes a vertical tube furnace with camera to detect shrinkage in dogbone samples [20,22,39,41,71,72], a box furnace with front window for use of a camera [8], a commercial spark plasma sintering machine used without the usual graphite mould [31], a vertical furnace adapted to hold pellets by the use of alumina supporting bars with [26,37] or without [36] significant applied load, and a modified system holding suspended dogbones designed for in situ X-ray diffraction studies [23,73].…”

Section: Zirconiamentioning

confidence: 99%

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Flash sintering of ceramic materials

Dancer¹

2016

Mater. Res. Express

160

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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: Flash Sintering Apparatusmentioning

confidence: 99%

Section: Specimen Geometrymentioning

confidence: 99%

Section: Zirconiamentioning

confidence: 99%

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Flash sintering of ceramic materials

Dancer¹

2016

Mater. Res. Express

160

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“…Sintering (Pozzoli et al, 2015), (Caliman et al,2015) is the most important production process of powder metallurgy. It is the process of increasing the grain size of the powder particles by increasing the strength of the particles and the strength of the powder components by heating them at a temperature below the melting temperature (Kang,2004).…”

Section: Introductionmentioning

confidence: 99%

Energy Consumption Analysis of Sintering Temperature Optimization of Pure Aluminum Powder Metal Compacts Sintered by Using The UHFIS

Taştan¹,

Gökozan²,

Çavdar³

et al. 2017

Uluslararası Muhendislik Arastirma Ve Gelistirme Dergisi

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In this study, pure aluminum (Al) powder metal (PM) compacts are sintered conventional or induction systems. PM compacts are sintered by furnace at 600ºC in 60 minutes in the conventional sintering process. In the other process, PM compacts are sintered by induction system at seven different sintering temperatures from 550 C to 610 C in 4 minutes. 2.8 kW, 900 kHz ultra-high frequency induction system (UHFIS) used for heating application of induction sintering process. Densities and hardness values are investigated for both processes. During these sintering processes, all energy consumption results are measured and calculated, then compared with each other. The effects of the sintering time increase in the induction sintering process on energy cost have been analyzed. Optimum sintering temperature of the induction sintering process is determined. It has been seen that the cheaper energy cost is obtained by the induction system for sintering application.

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“…(b) um forno de dilatômetro adaptado [32] ou dispositivos similares [43,44] onde algum tipo de carga, geralmente muito baixa, é necessária para posicionar a amostra.…”

Section: Sinterização Flashunclassified

Contribuição ao estudo de sinterização sem pressão assistida por campo elétrico de zircônia tetragonal estabilizada com ítria

Carvalho¹

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Experiments on sintering ZrO2: 3 mol% Y2O3 polycrystalline ceramics (Y-TZP, hereafter 3YSZ) were carried out by three methods: heating following the room temperature-1400 o C-room temperature profile (conventional sintering), heating from room temperature to 1000-1100 o C under an applied AC electric field (dynamic electric field-assisted sintering), and heating to 1000-1100 o C for application of an AC electric field (isothermal electric field-assisted sintering). The last method was performed under different specimen conditions (green pellets, green pellets isostatically pressed with different loads, pellets pre-sintered at 1400 o C) and different experimental conditions (different frequencies of the AC electric field, DC electric fields, different limitation of the electric current densities, applying loads simultaneously to application of the electric field). All 3YSZ sintered samples, besides having their apparent densities determined, had their surfaces observed in a scanning electron microscope to evaluate average grain size and distribution of grain sizes (some, along the surface from the center to the border). Moreover, impedance spectroscopy analyses were carried out to evaluate the intergranular (mainly grain boundary) and intragranular (bulk) contributions to the electrical resistivity. The primary idea was to collect data on electric field-assisted sintering looking for understanding the mechanisms behind that sintering method, known to produce dense ceramic pieces at temperatures lower than those used in conventional sintering, in short times and inhibiting grain growth. The main results show that 1) the shrinkage level depends on the AC frequency, 2) the larger the porosity the higher the electric field effect, 3) higher current densities promotes higher densification up to a limit that could damage the sample, 4) the electric current pulse follows preferentially the intergranular instead of the bulk pathway, and 5) electric field-assisted sintered specimens show enhanced grain boundary conductivity. A mechanism for the electric field-assisted sintering is proposed based on that 1) Joule heating is the primary event, 2) the electric current, as a result of the electric field, follows the intergranular pathway, 3) Joule heating diffuses chemical species depleted at the interfaces back to the bulk, increasing the defect concentration, leading to the enhancement of the bulk conductivity, and 4) that same Joule heating is responsible for the decrease of the potential barrier at the space charge region, inhibiting the blocking of oxide ions at the grain boundaries.

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A simple flash sintering setup under applied mechanical stress and controlled atmosphere

Abstract: Graphical abstract

Cited by 20 publications

References 12 publications

Flash sintering of ceramic materials

Flash sintering of ceramic materials

Energy Consumption Analysis of Sintering Temperature Optimization of Pure Aluminum Powder Metal Compacts Sintered by Using The UHFIS

Contribuição ao estudo de sinterização sem pressão assistida por campo elétrico de zircônia tetragonal estabilizada com ítria

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