Barium titanate derived from mechanochemically activated powders

Kong, Ling Bing; Ma, Jan; Huang, Haitao; Zhang, R.F; Que, Wenxiu

doi:10.1016/s0925-8388(01)01925-9

Cited by 105 publications

(54 citation statements)

References 21 publications

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“…1, we also show the powder X-ray diffraction patterns for the polyol precursor solution after a TGA run terminated at two temperatures (between baking at 150°C and annealing at 700°C). The as-baked product at 150°C is found to be in crystalline Ba 2 Ti 2 O 5 CO 3 intermediate phase [19][20][21][22][23]. As the annealing temperature increased, the peaks of the crystalline intermediate phases formed at 150°C decreased by thermal decomposition and then the peaks of the polycrystalline BaTiO 3 begins to form when annealed above 500°C with weak diffraction peaks for the intermediate phase (not shown in figure).…”

mentioning

confidence: 94%

“…Considering the general formation mechanism, it has been reported that BaTiO 3 forms either by a nucleation process at the BaCO 3 /TiO 2 interface or through a decomposition of crystalline Ba 2 Ti 2 O 5 CO 3 intermediate phase [19][20][21][22][23]. The first of them proposed that the solution-derived metal organic precursors decompose to form a finely divided mixture of BaCO 3 and TiO 2 , which subsequently reacts to form BaTiO 3 on heating at 600-700°C [20].…”

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confidence: 99%

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Ultrathin barium titanate films by polyol thermal decomposition process

2010

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We have successfully fabricated barium titanate (BaTiO 3 ) films on Si (100) and Pt(111)/Ti/SiO 2 /Si substrates using the polyol thermal decomposition (PTD) process by spin-coating technique. In PTD process, we confirmed that the crystalline oxycarbonate Ba 2 Ti 2 O 5 CO 3 films were directly formed as a consequence of evaporation of polyol precursor solution prepared simply by mixing metal chlorides and ethylene glycol, and then converting them into crystalline BaTiO 3 films through thermal decomposition at [500°C. This feature makes it possible to grow densely packed and crack-free BaTiO 3 films as thin as 70 Å per cycle. Although PTD is described here for a complex metal-oxide film of BaTiO 3 , other simple and complex metal-oxide thin films with high-dielectric constant materials are also likely to be suitable for deposition with accurate control of film thickness and composition using the polyol precursor solutions.Metal-oxide thin films, such as AO and ABO 3 , are important components in a wide array of electronic and optical devices, and their study and manufacture involve major aspects of current science and technology [1]. The ability to deposit and tailor reliable metal-oxide films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. Many different methods are used to make these thin films, such as various physical and chemical vapor depositions mainly dependent on vacuum deposition techniques, and many new techniques have been developed [1][2][3]. However, the use of these vacuum deposition techniques, the high cost of necessary equipment, and restriction of coatings on a relatively small area have limited their potential applications [4]. On the other hand, chemical solution depositions (CSD) such as sol-gel and metallo-organic decomposition (MOD) are more cost-effective, but many metal oxides cannot be deposited, and the control of stoichiometry is not always possible owing to differences in chemical reactivity among the metals [5]. In particular, precise control of film thickness, crystallinity, and morphology are significant problems to be overcome in CSD [6].One of the challenges in solution-based processes of complex metal-oxide films has been to produce high-quality films with desired chemical composition. The sol-gel method among the CSD processes is one of the most important approaches, which are being extensively used for the fabrication of complex oxide thin films. The sol-gel method show attractive advantages due to the fact that films with extremely uniform composition over large areas can be obtained from chemical solution deposition [7]. A key issue of any CSD thin films processing is the chemistry of precursor solution, which governs the properties of the final oxide layer. Even more challenging for sol-gel processing of complex metal-oxides is the identification of a solvent system in which the multiple organometallic precursors are reciprocally compatible. Recently, a few attempts have been reportedly made to ad...

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Ultrathin barium titanate films by polyol thermal decomposition process

2010

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“…It is well known that barium titanate based materials provide properties that are important for a variety of electrical and electronical applications [1,2]. Many researches have emphasized the importance of synthesizing process of BaTiO 3 powder on the dielectric properties of the ceramic [3].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Barium Titanate Ceramic Powders by Raman Spectroscopy

Lazarević

Romčević

Vijatović³

et al. 2009

Acta Phys. Pol. A

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Barium titanate, BaTiO3 ceramic powders were prepared by mechanochemical synthesis and by the Pechini method. A powder mixture of BaO and TiO2 was treated in a planetary ball mill in an air atmosphere for up to 1 h, using zirconium oxide vial and zirconium oxide balls as the milling medium. After 60 min BaTiO3 phase was formed. In both ways BaTiO3 ceramics were sintered after 2 h on 1300 • C without pre-calcinations step. The heating rate was 10 • C min −1 . The formation of phase and crystal structure of BaTiO3 was approved by X-ray diffraction analysis and the Raman spectroscopy. The morphology and microstructure of obtained powders were examined by scanning electron microscopy method. Sharp phase transition from ferroelectric to paraelectric state was observed. The hysteresis loop is very well performed with regular sharp characteristic of ferroelectric materials.

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“…Cho et al reported that BaTiO 3 particles prepared from organic precursors are in the tetragonal phase when they are larger than 20 nm. 6 Several routes for the synthesis of BaTiO 3 particles, including coprecipitation, 7 sol-gel, hydrothermal synthesis, 1 and mechanochemical 8 techniques have been reported. Hydrothermal and solid-state processes are used commercially for the preparation of BaTiO 3 powder because of their low cost and ease of production.…”

Section: Introductionmentioning

confidence: 99%

“…In solidstate synthesis, BaCO 3 , TiO 2 and other additives are mechanically milled and calcined at a high temperature to permit solid-state reactions. 8 Hydrothermal processing can be used to prepare tetragonal BaTiO 3 particles with an average particle size of 80 nm at 240°C for 12 h. 9 The disadvantages of these processes include inhomogeneous chemical composition, strong agglomeration, a rather poor morphology, and difficulties in controlling crystal size. A surface modifier is necessary to prevent agglomeration of the nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Agglomerate-free BaTiO₃ particles by salt-assisted spray pyrolysis

et al. 2002

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Optimum conditions for the synthesis of nonagglomerated BaTiO 3 particles by salt-assisted spray pyrolysis (SASP) were investigated. The effect of particle residence time in the reactor and salt concentration on the crystallinity and surface morphology of BaTiO 3 was examined by x-ray diffraction and scanning electron microscopy. Mixtures of a metal chloride or nitrate salt, dissolved in aqueous precursor solutions, were sprayed by an ultrasonic atomizer into a five-zone hot-wall reactor. By increasing the salt concentration or the particle residence time in the hot zone, the primary particle size was increased, and its surface texture was improved compared to BaTiO 3 particles prepared by conventional spray pyrolysis. The SASP-prepared BaTiO 3 crystal was transformed from cubic to tetragonal by simply increasing the salt concentration at constant temperature and residence time. Further thermal treatments such as calcination or annealing are not necessary to obtain nonagglomerated tetragonal BaTiO 3 (200-500 nm) particles with a narrow size distribution. Increasing the carrier gas flow rate and decreasing the residence time in the hot zone resulted in cubic BaTiO 3 particles about 20 nm in diameter.

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Barium titanate derived from mechanochemically activated powders

Cited by 105 publications

References 21 publications

Ultrathin barium titanate films by polyol thermal decomposition process

Ultrathin barium titanate films by polyol thermal decomposition process

Characterization of Barium Titanate Ceramic Powders by Raman Spectroscopy

Agglomerate-free BaTiO₃ particles by salt-assisted spray pyrolysis

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Barium titanate derived from mechanochemically activated powders

Cited by 105 publications

References 21 publications

Ultrathin barium titanate films by polyol thermal decomposition process

Ultrathin barium titanate films by polyol thermal decomposition process

Characterization of Barium Titanate Ceramic Powders by Raman Spectroscopy

Agglomerate-free BaTiO3 particles by salt-assisted spray pyrolysis

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Agglomerate-free BaTiO₃ particles by salt-assisted spray pyrolysis