Porcelain stoneware consolidation by flash sintering

Biesuz, Mattia; Abate, Woinshet Diro

doi:10.1111/jace.15162

Cited by 36 publications

(55 citation statements)

References 43 publications

(87 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It might originate from the localized thermal gradient at the microstructural level. As shown elsewhere, during electric field‐assisted consolidation of insulating materials local overheating or even melting of the grain boundaries occurs. Thus, such temperature gradients in the grain might cause defect redistribution and contribute to explain the larger Sr segregation.…”

Section: Resultssupporting

confidence: 52%

See 1 more Smart Citation

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

et al. 2019

Self Cite

View full text Add to dashboard Cite

In the present work the effect of electric field assisted treatments, i. e. flash sintering, on the physicochemical properties and surface reactivity of SrTiO3 nanoparticles is investigated. The materials were prepared by a hydrothermal approach and consolidated at high temperatures by conventional and electric field assisted procedures. The exposure to an electric field from 300 to 900 V/cm allowed rapid consolidation with progressive reduction of the grain growth and the shrinkage of the specific surface area to 22% and 43%, respectively. XPS analyses evidenced increasing Sr segregation at the surface if voltage was applied during the treatment. The corresponding presence of Sr vacancies in the perovskite lattice was demonstrated by ESR spectroscopy. Both techniques pointed out the appearance of highly oxidative O− species in all ceramics. The materials reactivity was investigated by methane oxidation, chosen as model high temperature catalytic reaction. With respect to conventionally treated SrTiO3, the surface area normalized reaction rate significantly improved for the ceramics exposed to electric field, until a maximum of three times for the material treated at 900 V/cm. Such enhanced properties were ascribed to the larger extent of Sr enrichment and in particular to the correlated field‐induced defect structure perturbation.

show abstract

Section: Resultssupporting

confidence: 52%

“…However, an interaction between the elelctric field/current and the defect chemistry cannot be ruled out. As a matter of fact, field‐induced defect perturbation has been often proposed as the pivotal mechanism for field‐assisted sintering of ceramics …”

Section: Resultsmentioning

confidence: 99%

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…The application of external electric field combined with thermal heat expected to increase the entropy, hence induce amorphicity [47]. Flash experiments of porcelain by Biesuz et al [50] together with fast heating without an electric current confirmed the direct effect of the electric field on softening of the glassy phase at lower temperatures. The effect of rapid sintering due to rapid heating in the absence of electric field [22] was marginal in amorphous porcelain [50].…”

Section: Discussionmentioning

confidence: 90%

On thermal runaway and local endothermic/exothermic reactions during flash sintering of ceramic nanoparticles

Chaim

Estournès

2018

J Mater Sci

View full text Add to dashboard Cite

OATAO is an open access repository that collects the work of some Toulouse researchers and makes it freely available over the web where possible. ABSTRACTNumerical analysis of the heat balance at the flash event during flash sintering of granular ceramic nanoparticles was performed assuming continuum solid state as well as simultaneous surface softening/liquid formation and current percolation through the nanoparticle contacts. Assuming inter-particle radiations in the specimen volume, the electric Joule heat generated at the nanoparticle contacts partially lost by radiation from the specimen external surfaces. Considering the thermal effects due to rapid heating rate and freemolecular heat conduction regime, high-temperature gradients between the nanoparticle surfaces and the surrounding gas were developed. The attractive capillary forces, induced by the particle surface softening/liquid at the percolation threshold, lead to rapid rearrangement and densification of the nanoparticles. The excess Joule heat, already at the flash event, suffices the excess internal heat that is necessary for partial or full melting. Particle surface softening/liquid formation is a transient process, hence followed by crystallization immediate after the nanoparticle rearrangement. Thermal runaway is associated with local surface softening/melting and its solidification.

show abstract

“…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

View full text Add to dashboard Cite

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.

show abstract

Porcelain stoneware consolidation by flash sintering

Cited by 36 publications

References 43 publications

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

On thermal runaway and local endothermic/exothermic reactions during flash sintering of ceramic nanoparticles

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

Contact Info

Product

Resources

About

Porcelain stoneware consolidation by flash sintering

Cited by 36 publications

References 43 publications

Enhancement of the SrTiO3 Surface Reactivity by Exposure to Electric Fields

Enhancement of the SrTiO3 Surface Reactivity by Exposure to Electric Fields

On thermal runaway and local endothermic/exothermic reactions during flash sintering of ceramic nanoparticles

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

Contact Info

Product

Resources

About

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields