Journal ArticleDOI
Phase Composition of Reduced and Reoxidized Barium Titanate
H. Arend,L. Kihlborg +1 more
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TLDR
In this paper, an oxygen-deficient hexagonal phase in oxygen at 850°C for 2 h produces stoichiometric samples which are still hexagonal, whereas the tetragonal/cubic structure is restored by heating for 1 h at 1350°C.Abstract:
Reducing high-purity BaTiO3 in hydrogen for 1 h at 1275°C leads to an oxygen deficiency x= 0.0036 in BaTiO3–x with maintenance of the tetragonal/cubic perovskite-type structure. Reduction at 1325° C leads to x= 0.0073 and brings about transformation to the hexagonal modification. Up to 1500°C (x= 0.0233) no further phase change occurs. Annealing the oxygen-deficient hexagonal phase in oxygen at 850° C for 2 h produces stoichiometric samples which are still hexagonal, whereas the tetragonal/cubic structure is restored by heating for 1 h at 1350°C. The unit cell found for the hexagonal phase is somewhat smaller than previously reported.read more
Citations
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Journal ArticleDOI
Nonstoichiometric disorder in single-crystalline BaTiO3 at elevated temperatures
N.G. Eror,D.M. Smyth +1 more
TL;DR: In this paper, the electrical conductivity of single-crystalline BaTiO 3 was measured over the temperature range 800-1200°C while in thermodynamic equilibrium with oxygen partial pressures from 10 0 to 10 −19 atm.
Journal ArticleDOI
High resistivity BaTiO3 ceramics sintered in CO-CO2 atmospheres
I. Burn,G. H. Maher +1 more
TL;DR: In this paper, a barium titanate ceramic containing 13.5 mol % calcium zirconate was doped with oxides of various metals that were considered likely on the basis of ionic size and valence to enter the small cation lattice with charge less than 4+.
Journal ArticleDOI
Structure and electrical properties of oxygen-deficient hexagonal BaTiO3
TL;DR: In this article, the authors used neutron diffraction data to determine the crystal structure of a series of oxygen-deficient barium titanate powders, which were prepared by reduction of stoichiometric, tetragonal BaTiO============ 3======
Journal ArticleDOI
Ti‐Rich Nonstoichiometric BaTiO3: I, High‐Temperature Electrical Conductivity Measurements
S. A. Long,Robert N. Blumenthal +1 more
Journal ArticleDOI
On the preparation of pure, doped and reduced KNbO3 single crystals
U. Flückiger,H. Arend +1 more
TL;DR: In this paper, a top-seeded pulling procedure based on a defined powder synthesis of KNbO 3, a revision of the K 2 O-Nb 2 O 5 phase diagram, a study of the exchange between crystal and melt via gas phase and the description of the apparatus used are reported.
References
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Journal ArticleDOI
A Method for Growing Barium Titanate Single Crystals
Journal ArticleDOI
Preparation of barium titanyl oxalate tetrahydrate for conversion to barium titanate of high purity
TL;DR: In this article, a procedure was described for preparing barium titanyl oxalate tetrahydrate, BaTiO (Cz0 4h4HzO), in which the mole ratio of TiOz to BaO is unity.
Journal ArticleDOI
The crystal structure of hexagonal barium titanate
R. D. Burbank,H. T. Evans +1 more
TL;DR: In this article, the crystal structure of hexagonal barium titanate has been determined by X-ray methods and the structure is built up of six close-packed layers of Ba and O ions, each layer consisting of one Ba to three O ions having the packing sequence ABCACB.
Journal ArticleDOI
An Investigation of the Cubic-Hexagonal Transition in Barium Titanate
R M Glaister,H F Kay +1 more
TL;DR: In this paper, the perovskite-type barium titanate was converted to the hexagonal polymorph by firing in a hydrogen atmosphere at 1330°C, 130° lower than that previously reported for firing in air.