Single step densification of high permittivity BaTiO3 ceramics at 300 ºC

Tsuji, Kosuke; Ndayishimiye, Arnaud; Lowum, Sarah; Floyd, Richard D.; Wang, Ke; Wetherington, Maxwell; Maria, Jon Paul; Randall, Clive A.

doi:10.1016/j.jeurceramsoc.2019.12.022

Cited by 98 publications

(47 citation statements)

References 45 publications

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“…Preliminary results on BaTiO 3 indicate that molten hydroxides solvents are effective sintering aids for the densification during cold sintering. 28 In cold sintering, flux solvents enable the densification of ceramics following pressure-solution creep, a stress driven mass transfer mechanism following chemical potential gradients. [29][30][31][32][33] Figure 1 shows the evolution of the relative density of CeO 2 with the sintering temperature.…”

Section: Densification Of Ceo 2 In a Naoh-koh Fluxmentioning

confidence: 99%

Single‐step densification of nanocrystalline CeO₂ by the cold sintering process

et al. 2020

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This study reports the successful single‐step cold sintering of nanocrystalline cerium dioxide (CeO2) at temperatures ranging from 250°C to 400°C under 500 MPa, using molten hydroxides flux solvents. CeO2 ceramics obtained were 82 to 91% of the theoretical density. Structural and microstructural investigations of the as‐cold sintered CeO2 ceramics were conducted to further understand this new approach to cold sinter ceramics. Electrical conductivity measured by two‐point AC impedance demonstrated an activation energy for grain conductivity of 0.49 eV, with impedance spectra characteristic of nanoscale CeO2.

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Section: Densification Of Ceo 2 In a Naoh-koh Fluxmentioning

confidence: 99%

Single‐step densification of nanocrystalline CeO₂ by the cold sintering process

et al. 2020

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“…The eutectic mixture of NaOH and KOH at 170°C can be used to lower the synthesis temperature of various complex oxides. 32,33 For example, Tsuji et al 34 have employed this alkali flux in a one-step cold sintering process for BaTiO 3 at temperatures as low as 300°C in 12 h at 520 MPa. Sada et al 35 have shown that by using transient chemistry such as a Ba(OH) 2 octahydrate, the densification of BaTiO 3 by cold sintering can occur at a significantly reduced temperature and time of 225°C and 1 h. Recently, several chemical pathways for cold sintering have been described wherein upon cold sintering, the final product either: (1) retains the chemical composition or phase of the starting powders (e.g., ZnO, magnetite), (2) has a different chemical composition or phase than the starting powders (e.g., α-quartz), or (3) results in a new compound or chemical doping (e.g., BaTiO 3 cold sintered with BaOH 2 •8H 2 O or SrOH 2 •8H 2 O).…”

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Comparison of different sintering aids in cold sinter‐assisted densification of lead zirconate titanate

et al. 2021

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Various processing methods such as hydrothermal sintering, 1 spark plasma sintering, 2,3 microwave sintering, 4 liquid phase sintering, 5 and cold sintering 6 have been developed in an effort to lower sintering temperatures for bulk ceramics. In many of these approaches, a secondary liquid phase, often called a sintering aid, is used to lower processing temperatures significantly 7-9 via a liquid phase sintering mechanism. For example, compounds such as Cu 2 O/PbO, V 2 O 5 , P 2 O 5 , or LiBiO 2 facilitate densification of lead zirconate titanate (PZT) ceramics at <1000°C; without such liquid phases, PZT is typically sintered at 1200-1300°C. [10][11][12][13] Gutmanas et al. 14 first coined the term "cold sintering" in 1983 to refer to a plastic deformation in metals at low temperatures by utilizing extremely high uniaxial pressure: ~GPa's. Recently, the cold sintering process (CSP) has enabled densification of a number of ceramic materials at temperatures of 25-300°C in the presence of a transient liquid phase and applied uniaxial pressure: ~100 to 500 MPa (in an open system). 15 A broad range of material chemistries and material structures including metal oxides, 16 inorganic salts, 17 composites, 18,19 and multilayer systems 20 have been

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“…Once BT is a ferroelectric ceramic with a high dielectric constant, the inverse of this trend was expected. The literature for BT ceramics sintered by low-temperature techniques reports typically low permittivity values at room temperature (~600) [3,15]. This value is several times lower than the permittivity measured for ZnO and 10ZnO-90BT and higher than that measured for 80ZnO-20BT, 50ZnO-50BT, and 10ZnO-90BT.…”

Section: Resultsmentioning

confidence: 72%

“…These authors also obtained high densities only after a post-heat treatment at 900 °C. Recently, Tsuji et al [15] have demonstrated the CSP of BaTiO 3 in a single step at 300 °C; the sintering was performed under a uniaxial pressure of 520 MPa for 12 h using a molten hydroxide flux.…”

Section: Introductionmentioning

confidence: 99%

Cold sintering and electric characterization of ZnO-BaTiO3 composites

2021

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The sintering is an essential step in the processing of ceramics materials. A number of researchers have reported new techniques for sintering. However, in general, the process still demands high temperatures. This paper reports the results of the cold sintering of ZnO-BaTiO 3 composites. The microstructural, structural, and electric properties of the composite were studied. We obtained high densities (>95%) for pure ZnO and for the composition with 10 wt% of BaTiO 3 at a low temperature of sintering (250 °C/1 h). The increase of BaTiO 3 content reduced the grain size and degraded the sinterability of ZnO. The crystalline structure was investigated by X-ray diffraction and confirmed the separation of the phases after the cold sintering. The BaTiO 3 added in the composite reduced the values of conductivity, permittivity, and also the dielectric loss.

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Single step densification of high permittivity BaTiO3 ceramics at 300 ºC

Cited by 98 publications

References 45 publications

Single‐step densification of nanocrystalline CeO₂ by the cold sintering process

Single‐step densification of nanocrystalline CeO₂ by the cold sintering process

Comparison of different sintering aids in cold sinter‐assisted densification of lead zirconate titanate

Cold sintering and electric characterization of ZnO-BaTiO3 composites

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Single step densification of high permittivity BaTiO3 ceramics at 300 ºC

Cited by 98 publications

References 45 publications

Single‐step densification of nanocrystalline CeO2 by the cold sintering process

Single‐step densification of nanocrystalline CeO2 by the cold sintering process

Comparison of different sintering aids in cold sinter‐assisted densification of lead zirconate titanate

Cold sintering and electric characterization of ZnO-BaTiO3 composites

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Single‐step densification of nanocrystalline CeO₂ by the cold sintering process

Single‐step densification of nanocrystalline CeO₂ by the cold sintering process