Manipulation of matter by electric and magnetic fields: Toward novel synthesis and processing routes of inorganic materials

Guillon, Olivier; Elsässer, Christian; Gutfleisch, Oliver; Janek, Jürgen; Korte‐Kerzel, Sandra; Raabe, Dierk; Volkert, Cynthia A.

doi:10.1016/j.mattod.2018.03.026

Cited by 77 publications

(53 citation statements)

References 148 publications

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“…With respect to conventional methods, these strategies notably reduce the reaction time and temperature and are therefore regarded as highly sustainable and environmentally friendly . If microwave‐assisted syntheses covered a pivotal role in the last decades, the use of electric and magnetic fields recently emerged as novel strategy towards synthesis and the processing of inorganic materials . In addition to the energy‐saving character, these methods are very appealing because of i) the possibility to synthesize materials that cannot be prepared by conventional methods, ii) the design of materials with specific microstructure and textures and iii) control of defect formation and mobility …”

Section: Resultsmentioning

confidence: 99%

“…[1] If microwave-assisted syntheses covered a pivotal role in the last decades, [2][3][4] the use of electric and magnetic fields recently emerged as novel strategy towards synthesis and the processing of inorganic materials. [5] In addition to the energy-saving character, these methods are very appealing because of i) the possibility to synthesize materials that cannot be prepared by conventional methods, [6] ii) the design of materials with specific microstructure and textures [7] and iii) control of defect formation [8] and mobility. [9] The consolidation of ceramic materials is an important technological requirement for many high temperature applications such as solid-oxide fuel cells, thermoelectrics and catalysis.…”

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confidence: 99%

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Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

et al. 2019

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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.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

et al. 2019

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“…External magnetic fields during processing influence grain growth and as such have been proposed as an additional degree of freedom to control the grain structure, see [14,15] for reviews. The PFC model has been extended to include magnetic interactions in [16,17] and was used in [18] to explain the complex interactions between magnetic fields and solid-state matter transport.…”

Section: Introductionmentioning

confidence: 99%

Magnetically induced/enhanced coarsening in thin films

Backofen

Voigt

2020

Phys. Rev. Materials

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External magnetic fields influence the microstructure of polycrystalline materials. We explore the influence of strong external magnetic fields on the long time scaling of grain size during coarsening in thin films with an extended phase-field-crystal model. Additionally, the change of various geometrical and topological properties is studied. In a situation which leads to stagnation, an applied external magnetic field induces further grain growth. The induced driving force due to the magnetic anisotropy defines the magnetic influence of the external magnetic field. Different scaling regimes are identified dependent on the magnetization. At the beginning, the scaling exponent increases with the strength of the magnetization. Later, when the texture becomes dominated by grains preferably aligned with the external magnetic field, the scaling exponent becomes independent on the strength of the magnetization or stagnation occur. We discuss how the magnetic influence change the effect of retarding or pinning forces, which are known to influence the scaling exponents. We further study the influence of the magnetic field on the grain size distribution (GSD), next neighbor distribution (NND) as well as grain shape and orientation. If possible, we compare our predictions with experimental findings. arXiv:1909.00527v4 [cond-mat.mtrl-sci]

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“…Sintering a ceramic body by applying an electric field without application of pressure at a temperature below the temperature usually used for sintering is a technique that has been applied since it was first proposed in 2010 [1]. Several review papers have shown the application of this technique to electroceramics, insulators, semiconductors and mainly, ionic conductors [2][3][4][5][6]. Most of the studied ionic conductors are either 3 mol% or 8 mol% stabilized zirconia [1,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Section: Flash Sinteringmentioning

confidence: 99%

Electrical Behavior of Electric Field-Assisted Pressureless Sintered Ceria-20 mol% Samaria

et al. 2019

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CeO2:20 mol% Sm2O3 green ceramic pellets were sintered conventionally at 1500 °C/2 h and flash sintered by applying a 200 V cm−1 electric field at 800 °C, 1000 °C and 1200 °C. The thickness shrinkage of the pellets was followed bythe specimen being positioned inside a dilatometer adapted with platinum electrodes and terminal leads connected to a power supply for application of the electric voltage. The microstructure of the surfaces of the sintered samples were observed in a scanning electron microscope. The electrical properties were evaluated by the impedance spectroscopy technique in the 5 Hz–13 MHz frequency range from 210 °C to 280 °C. The main results show that (i) the final shrinkage level is nearly independent of the temperature when the electric field is applied and slightly better than that of the 1500 °C sintered pellet, and (ii) the bulk conductivity of the sample flash sintered at 1200 °C is similar to that of the sample sintered at 1500 °C. The availability of a pathway for the electric current pulse derived from the applied electric field is proposed as the reason for the achieved shrinkages. Scavenging of the grain boundaries by Joule heating is proposed as the reason for the improved oxide ion bulk conductivity.

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Manipulation of matter by electric and magnetic fields: Toward novel synthesis and processing routes of inorganic materials

Cited by 77 publications

References 148 publications

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

Magnetically induced/enhanced coarsening in thin films

Electrical Behavior of Electric Field-Assisted Pressureless Sintered Ceria-20 mol% Samaria

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Manipulation of matter by electric and magnetic fields: Toward novel synthesis and processing routes of inorganic materials

Cited by 77 publications

References 148 publications

Enhancement of the SrTiO3 Surface Reactivity by Exposure to Electric Fields

Enhancement of the SrTiO3 Surface Reactivity by Exposure to Electric Fields

Magnetically induced/enhanced coarsening in thin films

Electrical Behavior of Electric Field-Assisted Pressureless Sintered Ceria-20 mol% Samaria

Contact Info

Product

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Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields

Enhancement of the SrTiO₃ Surface Reactivity by Exposure to Electric Fields