Microwave Synthesis of Yttrium Iron Garnet Powder

Kimura, Teiichi; Takizawa, Hirotsugu; Uheda, Kyota; Endo, Tadashi; Shimada, Masahiko

doi:10.1111/j.1151-2916.1998.tb02720.x

Cited by 47 publications

(14 citation statements)

References 9 publications

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“…The time for the synthesis of yttrium iron garnet significantly reduces. This is attributed to both the rapid heating of the starting component and the nonthermal effect of the microwave field on the interdiffusion of the components [6]. The rapid formation of YVO 4 : Eu +3 under MWH is also attributed to the intensive heating of the mixture due to the strong microwave absorptivity of vanadium oxide present in the starting powder mixture [7].…”

mentioning

confidence: 94%

Diffusion processes and structurization in microwave sintering of BaTiO3–SrTiO3 and Al2O3–Cr2O3 powder systems with complete miscibility

Get’man

Panichkina

Radchenko

et al. 2009

Powder Metall Met Ceram

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microwave heating (24 and 30 GHz) (MWH) and conventional heating (CH). A gyrotron system is used for MWH and electric furnaces for CH. The samples are prepared by sintering of ultrafine powder mixtures at 1000-1300°C (MWH) and 1700°C (CH). Mercury porometry is used to determine the mean pore size and specific surface area of the samples. The Barus-Bechgold method is employed to find the maximum pore contraction. A quantitative microscopic analysis of the samples is carried out. The content of solid solution is determined using x-ray analysis. The volume and local shrinkage is calculated. Relationships between the local and volume shrinkage, pore structure parameters, and amounts of solid solutions for different heating conditions are shown. The results reveal different diffusion processes in sintering of powder systems with complete miscibility of components under MWH and CH.The faster compaction of monophase and multiphase powder bodies when sintered under microwave heating (MWH) is attributed by many researchers to more intensive mass transfer. Interdiffusion proceeds in multiphase powder bodies along with compaction. It is assumed that diffusion proceeds faster in microwave heating not only because of temperature but also because of the microwave field as such, i.e., its nonthermal effect on the mass transfer during sintering [1]. It is reported, for example, in [2] that the activation energy of oxygen diffusion in alumina decreases by 40% in MWH. The nonthermal effect of the microwave field on the mass transfer in ion crystals has been confirmed by theory and experiment [3].

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mentioning

confidence: 94%

Diffusion processes and structurization in microwave sintering of BaTiO3–SrTiO3 and Al2O3–Cr2O3 powder systems with complete miscibility

Get’man

Panichkina

Radchenko

et al. 2009

Powder Metall Met Ceram

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“…On the other hand, ␣-Fe 2 O 3 showed a moderate temperature increase, with a saturation temperature of 260°C at 2 kW. It is quite curious that ␣-Fe 2 O 3 showed moderate coupling with microwaves in this study, because the temperature of ␣-Fe 2 O 3 rapidly increased to 680°C at 1 kW in our previous study 10 are different in each other (but the purity and the particle-size grades are the same), so the difference in surface structure or defect concentration may cause a difference in microwave-material coupling. Additional study is needed to clarify this problem.…”

Section: Methodsmentioning

confidence: 54%

Rapid Formation and Growth of Bixbyite‐Type (In_0.67Fe_0.33)₂O₃ by 28 GHz Microwave Irradiation

Takizawa

Uheda

Endo

2000

Journal of the American Ceramic Society

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In 0.67 Fe 0.33 ) 2 O 3 with the bixbyite structure was synthesized via 28 GHz microwave irradiation, using multimode microwave heating equipment. Indium sesquioxide strongly absorbs 28 GHz microwaves, and this strong coupling with microwave energy can be used to drive a reaction with iron sesquioxide. A mixture of In 2 O 3 and ␣-Fe 2 O 3 powders (In:Fe ratio of 2:1) was irradiated with microwaves at a frequency of 28 GHz. The mixture was heated to 1400°C during the microwave irradiation. The formation of a solid solution was completed within a minute, which indicated a drastic enhancement of the reaction rate. Scanning electron microscopy revealed remarkable grain growth under microwave irradiation.

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“…[28][29][30][31][32] Recently, Binner et al showed that ZnO grain growth was clearly enhanced by microwaves. 29) They compared microwave/conventional hybrid heating with a pure conventional method for samples that had identical thermal histories.…”

Section: Microstructure Of Tio 2 -Sno 2 Pelletmentioning

confidence: 99%

Microstructural Control of the TiO2-SnO2 Binary System and Synthesis of SnO2 Nanowhiskers by Microwave Irradiation

2008

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SnO 2 single crystals (columnar crystals and silver grass-like nanowhiskers) were synthesized by selective microwave heating of a TiO 2 -SnO 2 mixture. The shape of the as-grown SnO 2 crystals is strongly dependent on the atmosphere during microwave irradiation. This is due to the difference in growth mechanisms, as revealed by in-situ surface observation under microwave irradiation, in addition to scanning and transmission electron microscopy observations of irradiated specimens. In a N 2 atmosphere, silver grass-like SnO 2 nanowhiskers were obtained. On the other hand, columnar SnO 2 crystals were obtained in air or an O 2 atmosphere. Photoluminescence and absorption spectra of the as-grown SnO 2 crystals were examined. Based on the analysis of a TiO 2 -SnO 2 pellet, it was found that the bottom was selectively heated, and SnO 2 sublimated by microwave irradiation. A density gradient texture of the sample pellet was formed.

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Microwave Synthesis of Yttrium Iron Garnet Powder

Cited by 47 publications

References 9 publications

Diffusion processes and structurization in microwave sintering of BaTiO3–SrTiO3 and Al2O3–Cr2O3 powder systems with complete miscibility

Diffusion processes and structurization in microwave sintering of BaTiO3–SrTiO3 and Al2O3–Cr2O3 powder systems with complete miscibility

Rapid Formation and Growth of Bixbyite‐Type (In_0.67Fe_0.33)₂O₃ by 28 GHz Microwave Irradiation

Microstructural Control of the TiO<SUB>2</SUB>-SnO<SUB>2</SUB> Binary System and Synthesis of SnO<SUB>2</SUB> Nanowhiskers by Microwave Irradiation

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Microwave Synthesis of Yttrium Iron Garnet Powder

Cited by 47 publications

References 9 publications

Diffusion processes and structurization in microwave sintering of BaTiO3–SrTiO3 and Al2O3–Cr2O3 powder systems with complete miscibility

Diffusion processes and structurization in microwave sintering of BaTiO3–SrTiO3 and Al2O3–Cr2O3 powder systems with complete miscibility

Rapid Formation and Growth of Bixbyite‐Type (In0.67Fe0.33)2O3 by 28 GHz Microwave Irradiation

Microstructural Control of the TiO<SUB>2</SUB>-SnO<SUB>2</SUB> Binary System and Synthesis of SnO<SUB>2</SUB> Nanowhiskers by Microwave Irradiation

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Rapid Formation and Growth of Bixbyite‐Type (In_0.67Fe_0.33)₂O₃ by 28 GHz Microwave Irradiation