Hydrothermal Synthesis of Dy (0.8 at%)-doped BaTiO3 Powders at 90°C, Their
Sintering
Behavior, and
Microstructures of Dy:BaTiO3 Powders Heated on Ti-Strips
Ersin Emre OREN and A. Cüneyt TAS
Department of Metallurgical and
Materials Engineering,
Middle East Technical University,
Ankara 06531, Turkey. (1993-1999)
* E. E. Oren and A. C. TAS, “Hydrothermal Synthesis of Dy-Doped BaTiO3 Powders,” Metallurgical and Materials Transactions, Vol. 30B, 1089-1093 (1999). Download PDF copy of this paper
* E. E. Oren and A. C. TAS,
"Hydrothermal Synthesis of Pure and Dy:BaTiO3
Powders at 90°C, Their Sintering Behavior, and Microstructures of Dy:BaTiO3
Powders Heated on Ti-Strips," 100th Annual Meeting of The American Ceramic
Society, Oral Presentation,
* E. E. Oren and A. C. TAS, "Hydrothermal Synthesis of Pure and Dy (0.8 at%)-doped BaTiO3 Powders at 90°C and their Sintering Behavior," in "Dielectric Ceramic Materials," Ceramic Transactions, Vol. 100, pp. 95-104, (Eds.) K.M. Nair and A.S. Bhalla, 1999, The American Ceramic Society, USA, ISBN 1-57498-066-1.
* A. C. TAS, “Hydrothermal Synthesis of Crystalline and BaCO3-free, Pure BaTiO3 Powders at 90°C in Air” Patent Application, Date: June 27, 1996, Turkish Patent Institute, Ankara, Turkey. No: 96/00539
* A. C. TAS, "Synthesis of Crystalline and Pure BaTiO3 Powders at 90°C," III. Ceramics Congress, Proceedings Book, Vol. 2, pp. 66-73, Istanbul, October 1996, Turkey. PDF
* E. E. Oren and A. C. Tas,
"Hydrothermal Synthesis of Pure and Dy:BaTiO3
Powders at 90°C and Their Sintering Behavior," IV. Ceramics Congress,
Proceedings Book, pp. 627-633, Eskisehir, September 1998, Turkey.
Abstract
Sub-micron (150-200 nm), monodisperse and spherical powders of Dy-doped
(0.8 at%) BaTiO3 have been prepared by “hydrothermal
synthesis” at 90°C in an air atmosphere. The slightly modified hydrothermal synthesis procedure adopted
in this work did not necessitate the utilization of strict and expensive
measures which were commonly required for the removal of free CO2 present
in the atmosphere. The synthesized powders were crystalline, pure, and did not
contain BaCO3 as an impurity phase. Dy-doped
BaTiO3 powders synthesized at 90°C
possessed the cubic (space group: Pm-3m) crystal structure.
Download the crystal structure
drawing
Download the SEM pic of
powders synthesized
Download the XRD charts of our barium titanate powders
A Tentative XRD Pattern for Hydrothermally Synthesized (90°C) "Pure" BaTiO3 Powders
(Cu-K-alpha radiation, Step: 0.02°, Count: 5 sec)
Lattice Parameters: Cubic, Pm-3m, a = 4.0186 Å, V = 64.89 Å3
No h k l d(obs) d(calc) res(d) 2th.obs 2th.calc I/Io
1
1 0 0
4.02000 4.01850 0.00140
22.094 22.101 21
2
1 1 0
2.84200 2.84158 0.00042
31.451 31.456 100
3
1 1 1
2.32050 2.32014 0.00036
38.774 38.780 22
4
2 0 0 2.00990
2.00930 0.00060 45.069
45.083 28
5
2 1 0
1.79730 1.79717 0.00013
50.754 50.758 7
6
2 1 1
1.64060 1.64059 0.00001
56.005 56.005 24
7
2 2 0
1.42090 1.42079 0.00011
65.654 65.660 12
8
3 0 0
1.33950 1.33953 -0.00003
70.206 70.204 4
9
3 1 0
1.27080 1.27079 0.00001
74.621 74.622 9
10
3 1 1
1.21160 1.21165
-0.00005 78.951
78.947 5
11
2 2 2
1.16000 1.16007 -0.00007
83.216 83.210 5
12
3 2 0
1.11450 1.11456 -0.00006
87.441 87.435 2
13
3 2 1
1.07400 1.07402 -0.00002
91.648 91.646 11
Dy:BaTiO3 powders were deposited onto titanium strips in concentrated ceramic suspensions with the aid of ultrasonification. Grain growth characteristics of pure and Dy-doped BaTiO3 pellets were investigated during sintering in an air atmosphere and compared with one another over the temperature range of 1200 to 1500°C. Sample characterization was achieved by XRD (X-ray diffraction), SEM (scanning electron microscopy), EDXS (energy dispersive X-ray spectroscopy), and Rietveld analysis.
