Effect of electric field (2.45 GHz) on sintering behavior of fully stabilized zirconia

Thridandapani, Raghunath R.; Folz, D. C.; Clark, David E.

doi:10.1016/j.jeurceramsoc.2015.01.004

Cited by 4 publications

(2 citation statements)

References 27 publications

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“…Ceramics produced by microwave sintering have high density and small grain size [59], though the mechanisms for the evolution of the microstructure during densification are not well understood [58] and extensive modelling efforts are in progress. It has been suggested by some researchers that densification during flash sintering occurs by a similar mechanism to microwave sintering [60,61]. Efforts to understand the relationships between the two processes include the development of the rapid "flash microwave sintering" carried out by Bykobv et al for ytterbium-doped yttrium lanthanum oxide [62].…”

Section: Comparison To Other Non-conventional Ceramic Firing Techniquesmentioning

confidence: 99%

Flash sintering of ceramic materials

Dancer¹

2016

Mater. Res. Express

159

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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

159

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“…The absorption of the microwave energy within the material depends on several factors such as the incident microwave frequency, the dielectric constant of the material, the dielectric loss of the material, and the distribution of the electric field within the material [25,26]. Many researchers [27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48] have reported enhanced kinetic rates, different reaction pathways, and/or different reaction products in several processes and materials using MW processing of materials when compared to conventional processing at the same or even at lower temperatures.…”

Section: Introductionmentioning

confidence: 99%

Microwave Crystallization of Lithium Aluminum Germanium Phosphate Solid-State Electrolyte

et al. 2016

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Lithium aluminum germanium phosphate (LAGP) glass-ceramics are considered as promising solid-state electrolytes for Li-ion batteries. LAGP glass was prepared via the regular conventional melt-quenching method. Thermal, chemical analyses and X-ray diffraction (XRD) were performed to characterize the prepared glass. The crystallization of the prepared LAGP glass was done using conventional heating and high frequency microwave (MW) processing. Thirty GHz microwave (MW) processing setup were used to convert the prepared LAGP glass into glass-ceramics and compared with the conventionally crystallized LAGP glass-ceramics that were heat-treated in an electric conventional furnace. The ionic conductivities of the LAGP samples obtained from the two different routes were measured using impedance spectroscopy. These samples were also characterized using XRD and scanning electron microscopy (SEM). Microwave processing was successfully used to crystallize LAGP glass into glass-ceramic without the aid of susceptors. The MW treated sample showed higher total, grains and grain boundary ionic conductivities values, lower activation energy and relatively larger-grained microstructure with less porosity compared to the corresponding conventionally treated sample at the same optimized heat-treatment conditions. The enhanced total, grains and grain boundary ionic conductivities values along with the reduced activation energy that were observed in the MW treated sample was considered as an experimental evidence for the existence of the microwave effect in LAGP crystallization process. MW processing is a promising candidate technology for the production of solid-state electrolytes for Li-ion battery.

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