Thermophysical properties of BaTiO3 ceramics prepared by aerodynamic levitation

Lee, Ki-Ju; Lee, Chi-Hoon; Lee, Keun Woo; Hwang, Woon Suk; Lee, Chi-Hwan; Yoda, Shinichi; Cho, Won-Seung

doi:10.1016/j.tca.2011.08.010

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…As a result, the specific heat can be calculated if the emissivity ε and the heat-transfer coefficient h are obtained. In this work, ε was calibrated to 0.9 referred from BaTiO 3 measured data 47 and h could be calculated by Whittaker equation 48 .…”

Section: Resultsmentioning

confidence: 99%

Polymorphic transition and nucleation pathway of barium dititanate (BaTi2O5) during crystallization from undercooled liquid

et al. 2019

Sci Rep

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The nucleation pathway plays an important role in vitrification, preparation of glass-ceramic composites and synthesis of metastable materials. In this paper, we studied the nucleation pathway of a novel ferroelectric BaTi 2 O 5 (BT2) during crystallization from undercooled liquid by aerodynamic levitation (ADL) containerless processing and structural analysis. An interesting polymorphic transition of BT2 regulated by the undercooling was observed during the crystallization process: the ferroelectric monoclinic phase ( γ -BT2) was fabricated at low undercoolings and the paraelectric orthorhombic metastable phase ( β -BT2) was obtained from hypercooled liquid. This polymorphic transition phenomenon corresponds to a non-classical nucleation pathway: metastable β -BT2 preferentially nucleates from undercooled melt and γ -BT2 is generated from β phase by solid-state phase transition. The two-step nucleation pathway stems from the structural heredity between the undercooled liquid and crystals. A stronger structural homology exists between the undercooled melt and β -BT2 than γ -BT2 based on diffraction data and atomic configurations analysis. This structural homology coupled with nucleation barrier calculation was used to elucidate the non-classical nucleation pathway of BT2 crystallization: the similarity of the structural unit (Ti-O polyhedra) between the undercooled liquid and the metastable β -BT2 reduces the nucleation barrier and contributes to the preferential precipitation of β -like clusters. This work reveals the formation route of BT2 from cooling melt, which not only benefits the synthesis and application of this novel functional material but also provides a guideline of the crystallization process of titanates from melt at atomic level.

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Section: Resultsmentioning

confidence: 99%

Polymorphic transition and nucleation pathway of barium dititanate (BaTi2O5) during crystallization from undercooled liquid

et al. 2019

Sci Rep

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“…The sample was undercooled immediately to T N , at which point nucleation was triggered. Solidification then occurred under quasiadiabatic conditions, leading to a rapid increase in temperature due to the release of latent heat [10].…”

Section: -mentioning

confidence: 99%

“…Recently, levitation techniques can prevent melt contamination from a container, minimize heterogeneous nucleation during solidification, and enable a liquid to achieve large supercooling at a relatively low cooling rate. This can be used to examine metastable phase formation [10,11]. This paper reports the fabrication conditions for YAG and YAG:Eu glass-ceramics using aerodynamic levitation.…”

Section: Introductionmentioning

confidence: 99%

Microstructure of rapidly quenched YAG-based glass–ceramics prepared by aerodynamic levitation

Lee

Jung

Yoda

et al. 2015

Ceramics International

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“…For the supercooled liquid (Δ T = 644 K), its temperature–time profile (Fig. 2a ) shows a significant recalescence associated with crystallization 45 . Diffraction patterns during the crystallization process of the supercooled liquid obtained from integrating the two-dimensional diffraction patterns (Fig.…”

Section: Resultsmentioning

confidence: 99%

Anomalous structure transition in undercooled melt regulates polymorphic selection in barium titanate crystallization

Yang

et al. 2021

Commun Chem

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The crystallization processes of titanates are central to the fabrication of optical and electrical crystals and glasses, but their rich polymorphism is not fully understood. Here, we show when and how polymorphic selection occurs during the crystallization of barium titanate (BaTiO3, BT) using in situ high energy synchrotron X-ray diffraction and ab initio molecular dynamic simulation. An anomalous structure transition is found in molten BT during cooling across the cubic-hexagonal transition temperature, which enables nucleation selection of BT by manipulating the undercooling: a cubic phase is preferred if nucleation is triggered at large undercooling, whereas a hexagonal phase is promoted at small undercooling. We further reveal that the nucleation selection between the cubic and the hexagonal phase is regulated by the intrinsic structure property of the melt, in particular, the degree of polymerization between Ti-O polyhedra. These findings provide an innovative perspective to link the polymorphic crystallization to the non-isomorphic structure transition of the melt beyond the conventional cognition of structural heredity.

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Thermophysical properties of BaTiO3 ceramics prepared by aerodynamic levitation

Cited by 6 publications

References 11 publications

Polymorphic transition and nucleation pathway of barium dititanate (BaTi2O5) during crystallization from undercooled liquid

Polymorphic transition and nucleation pathway of barium dititanate (BaTi2O5) during crystallization from undercooled liquid

Microstructure of rapidly quenched YAG-based glass–ceramics prepared by aerodynamic levitation

Anomalous structure transition in undercooled melt regulates polymorphic selection in barium titanate crystallization

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