Influence of electrical field on microstructure and mechanical properties of flash sintered alumina ceramics

Yang, Shoulei; Yang, Sheng; Zhu, Yinxiao; Fu, Xinxin; Wei, Pengfei; Fan, Lei; Zhang, Mengwen

doi:10.1016/j.ceramint.2022.03.033

Cited by 7 publications

(10 citation statements)

References 40 publications

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“…In addition, then the as‐prepared discs were pre‐sintered at 900°C in air for 2 h. The relative density of the pre‐sintered alumina discs is ∼60%. The pre‐sintered sample was then flash sintered at a furnace temperature of 1300°C in air using the procedure described previously 20,21 . Three kinds of experiments were carried out.…”

Section: Methodsmentioning

confidence: 99%

“…The pre-sintered sample was then flash sintered at a furnace temperature of 1300 • C in air using the procedure described previously. 20,21 Three kinds of experiments were carried out. The first experiment was carried out at the current limit of 7 mA/mm 2 and different electrical fields between 2500 and 4000 V/cm, aiming to study the densification in the flashing stage.…”

Section: Methodsmentioning

confidence: 99%

“…The authors proposed that the physical phenomenon of alumina FS is similar to dielectric breakdown, and the nonohmic conductivity during the sintering should be related to the pre‐breakdown behavior 22 . Instead of using a dog bone–shaped sample, we performed FS on MgO‐doped‐Al 2 O 3 plates 20,21 and showed that such high diameter‐to‐thickness ratio sample can also be flash sintered at a much higher threshold electrical field (2500 V/cm). Meanwhile, we found that the hardness and facture toughness of the flash sintered samples were remarkably improved, even higher than those of the hot‐pressed samples, likely due to the ultrafine grains of the former 20 .…”

Section: Introductionmentioning

confidence: 99%

“…16,17 The FS technique has also been applied to make alumina ceramics. [18][19][20][21] Compared to conducting and semiconducting ceramics, insulating alumina usually requires much higher electrical fields and furnace temperatures to initial FS. For example, Cologna et al reported that an electric field of 500 V/cm and furnace temperature of 1320 • C were required to initiate the FS of .25-wt.% MgO-doped Al 2 O 3 .…”

Section: Introductionmentioning

confidence: 99%

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Densification behaviors of Al₂O₃ ceramics during flash sintering

Yang

Pang

et al. 2022

Int J Applied Ceramic Tech

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The densification behaviors of MgO-doped-Al 2 O 3 ceramics in the flashing stage and the steady stage were investigated using the classic kinetic model. The results show that the most densification of MgO-doped Al 2 O 3 was completed during the flashing stage. The densification mechanism transferred from particle rearrangement resulted from Columbic force among particles under the effect of electrical field in the flashing stage to the lattice diffusion in the steady stage. Therefore, the densification rate in the steady stage dramatically decreased. Additionally, the estimated densification activation energy in the steady stage of flash sintering is 396 kJ/mol, much lower than the activation densification of lattice diffusion measured from conventional sintering, likely due to the effect of electric field/current-induced point defects on the diffusion.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Densification behaviors of Al₂O₃ ceramics during flash sintering

Yang

Pang

et al. 2022

Int J Applied Ceramic Tech

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“…They also showed that the densification of the flash sintered nearly pure alumina mainly depended on current density. In our previous reports, 20,21 the disc-shaped 0.25 wt% MgOdoped Al 2 O 3 ceramics was flash sintered, and it was found that the disc-shaped samples required higher threshold electrical field (2500 V/cm) for flash sintering. Additionally, the microstructure of the flash-sintered MgO-doped Al 2 O 3 ceramic discs not only related to the current density, but also to the applied electrical field.…”

Section: Introductionmentioning

confidence: 93%

Flash sintering of ultra‐high pure alumina ceramics with fine microstructure

et al. 2022

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The nearly fully dense ultra‐high pure (>99.99%) α‐Al2O3 ceramics were prepared by flash sintering at the furnace temperature of 1300°C. Compared with the samples sintered at 1300 and 1650°C without electrical field, the flash‐sintered samples exhibited remarkably improved density and finer grains. The flash‐sintered samples also exhibited high hardness, which is even higher than that of the hot‐pressed sample. Therefore, it is believed that flash sintering could be an effective technique for the preparation of ultra‐high pure alumina ceramics.

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