Influence of Microwave Irradiation Method on the Sintering of Barium Titanate with Liquid Phase

Yasuoka, Masahito; Shirai, Takashi; Nishimura, Yutsuki; Kinemuchi, Yoshiaki

doi:10.2109/jcersj.114.377

Cited by 8 publications

(5 citation statements)

References 8 publications

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“…In fact the Curie temperature in the microwave processed sample has been reduced by approximately 5 8C. Following the earlier work on microwave sintering of undoped BaTiO 3 [22] and the liquid phase sintering of BaTiO 3 [21] the most important finding of the present work is that microwaveassisted sintering yields superior electrical properties at lower temperatures and indeed in shorter processing times for the X7R type ceramics. There is clearly some form of athermal effect [11][12][13] in achieving such enhancement, but we have demonstrated the benefit of microwave-assisted techniques for processing low temperature, BaTiO 3 -based ceramics intended for use in multilayer capacitors.…”

Section: Resultssupporting

confidence: 60%

“…A number of workers have investigated the sintering of barium titanate based ceramics in a microwave field [16][17][18][19][20][21][22][23]. Humphrey and Anderson [16] were amongst the first groups to employ microwave processing.…”

Section: Microwave-assisted Sintering Of Electronic Ceramicsmentioning

confidence: 99%

“…Thakur et al [20] were able to sinter BaTiO 3 at 1450 8C in 25 min compared to 4 h by radiant heating. Yasuoka et al [21] demonstrated the benefit of a liquid phase in the microwave enhanced sintering of BaTiO 3 . Takahashi et al [22] showed that reducing the domain size in microwave sintered BaTiO 3 enhanced the piezoelectric d 33 coefficient.…”

Section: Microwave-assisted Sintering Of Electronic Ceramicsmentioning

confidence: 99%

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Enhanced microwave-assisted sintering of X7R ceramic dielectrics for use in multilayer capacitors

McInroy

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2010

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Section: Resultssupporting

confidence: 60%

Section: Microwave-assisted Sintering Of Electronic Ceramicsmentioning

confidence: 99%

Section: Microwave-assisted Sintering Of Electronic Ceramicsmentioning

confidence: 99%

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Enhanced microwave-assisted sintering of X7R ceramic dielectrics for use in multilayer capacitors

McInroy

Rowley

Freer

2010

Ceramics International

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“…Microwave irradiation was carried out in a tunable magnetron multimode microwave furnace (MW‐Master, Mino Ceramics Co. Ltd., Gifu, Japan) 13 . The green bodies were placed in a thermally‐insulated box and irradiated with 200 Wh of microwaves at 2.45 GHz in the presence of microwave‐absorbing dummy loads consisting of glass bottles, each filled with a mixture of polyvinyl alcohol flakes and alumina powder.…”

Section: Methodsmentioning

confidence: 99%

Production of Ceramic Green Bodies Using a Microwave‐Reactive Organic Binder

Sato

Kawai

Hotta

et al. 2007

Journal of the American Ceramic Society

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Because the pyrolysis of organic substances can result in the emission of harmful pollutant gases, a reduction in the use of organic binders is one aim of today's ceramics industry. A novel ceramic‐forming process was developed that requires considerably less organic binder than conventional techniques. The process involves immobilizing reactive molecules on the surfaces of the particles, which on subsequent irradiation with microwaves, form bridges that bind the entire particle assembly together. The chemical forces involved produce strong bonds, resulting in a significant reduction in the amount of organic binder that is required to maintain the shape of the ceramic green body. This method will help to decrease emissions of harmful gases produced from pyrolysis of the binder.

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“…Thus, a temperature gradient should be applied to the sample during the sintering process in order to prepare a grain size gradient in ceramics with homogeneous chemical composition. Such a localized temperature gradient can be induced by microwave sintering 14 Composition Gradient Actuators 291 (Yasuoka et al 2006). However, the temperature change is high enough only at the mm scale.…”

mentioning

confidence: 99%

Composition Gradient Actuators

Steinhausen

Beige

2008

Piezoelectric and Acoustic Materials for Transducer Applications

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Piezoelectric functionally graded materials (FGMs) are attractive alternatives to homogenous-single phase materials for actuator applications because of their reduced internal mechanical stresses and lower production costs. Furthermore, such FGM structures have increased band width if used as an ultrasonic transducer. One of the most effective ways to prepare piezoelectric and dielectric gradients based creating a gradient in chemical composition by powder processing prior to sintering. The sharp chemical interfaces between the green layers disappear because of diffusion during sintering. The chemical gradient is then transformed into a gradient in the piezoelectric properties by a poling process after sintering. Several models have been developed for the description of poling of layered systems, which is a formidable challenge. The ferroelectric properties, such as spontaneous polarization and coercive field strength, also depend on the local chemical composition. This causes an inhomogeneous electric field distribution, which is usually not stable in time because of conductive currents and space charges.In this chapter, different types of composition gradients for bending actuators are described. Combinations of hard and soft piezoelectric ceramics and electrostrictive and electroconductive materials are presented. The theoretical results are compared with experimental data for lead-free systems based on barium titanate. IntroductionFunctionally graded materials (FGMs) have a one or more dimensional gradient of at least one material property. Usually, several material properties change their values continuously in the direction of the gradient. Thus, a gradient in piezoelectric coefficients is often combined with a gradient in dielectric or elastic coefficients. Piezoelectric FGMs are suitable for applications where materials with different properties need to be mechanically connected. Thereby, residual mechanical stresses at interfaces between the different materials can be reduced. Piezoelectric FGMs with a gradient of the electromechanical properties can be used in micromechanical systems (MEMS), or as actuators for connecting piezoelectric active parts with substrates or other passive parts. In this way, reliability and lifetime of electromechanical devices can be improved. Furthermore, FGMs can be used to improve the bandwidth in ultrasonic applications (Sakamura et al. 2000).Monolithic bending actuators are a special application of piezoelectric FGMs. The bending effect strongly depends on the difference of the lateral strain at the top and the bottom surface of the actuator. Usually, two layers with different piezoelectric properties or with an electrode in between the layers are bonded together. It was shown that piezoelectric FGMs can reduce the mechanical stresses at the interface (Hauke et al. 2000). A good performance of the bending actuator depends on the quality of the piezoelectric gradient.Usually, the piezoelectric gradient in monolithic samples is obtained by creating a chemical composition gr...

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Influence of Microwave Irradiation Method on the Sintering of Barium Titanate with Liquid Phase

Cited by 8 publications

References 8 publications

Enhanced microwave-assisted sintering of X7R ceramic dielectrics for use in multilayer capacitors

Enhanced microwave-assisted sintering of X7R ceramic dielectrics for use in multilayer capacitors

Production of Ceramic Green Bodies Using a Microwave‐Reactive Organic Binder

Composition Gradient Actuators

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