The phase composition and sintering behavior of two commercially available 10mol%Sc2O31mol%CeO2ZrO2 ceramics produced by Daiichi Kigenso Kagaku Kogyo (DKKK) and Praxair have been studied. DKKK powders have been manufactured using a wet coprecipitation chemical route, and Praxair powders have been produced by spray pyrolysis. The morphology of the powders, as studied by scanning electron microscopy, has been very different. DKKK powders were presented as soft (100μm) spherical agglomerates containing 60100nm crystalline particles, whereas the Praxair powders were presented as sintered platelet agglomerates, up to 30μm long and 34μm thick, which consisted of smaller 100200nm crystalline particles. X-ray diffraction analysis has shown that both DKKK and Praxair powders contained a mixture of cubic (c) and rhombohedral (r) phases: 79% cubic +21% rhombohedral for DKKK powders and 88% cubic +12% rhombohedral for Praxair powders. Higher quantities of the Si impurity level have been detected in Praxair powder as compared to DKKK powder by secondary ion mass spectroscopy. The morphological features, along with differences in composition and the impurity level of both powders, resulted in significantly different sintering behaviors. The DKKK powders showed a more active sintering behavior than of Praxair powders, reaching 93–95% of theoretical density when sintered at 1300°C for 2h. Comparatively, the Praxair powders required high sintering temperatures at 15001600°C. However, even at such high sintering temperatures, a significant amount of porosity was observed. Both DKKK and Praxair ceramics sintered at 1300°C or above exist in a cubic phase at room temperature. However, if sintered at 1100°C and 1200°C, the DKKK ceramics exist in a rhombohedral phase at room temperature. The DKKK ceramics sintered at 1300°C or above exhibit cubic to rhombohedral and back to cubic phase transitions upon heating at a 300500°C temperature range, while Praxair ceramics exist in a pure cubic phase upon heating from room temperature to 900°C. However, if heated rather fast, the cubic to rhombohedral phase transformation could be avoided. Thus it is not expected that the observed phase transitions play a significant role in developing transformation stresses in ScCeZrO2 electrolyte upon heating and cooling down from the operation temperatures.

1.
Kharton
,
V. V.
,
Marques
,
F. M. B.
, and
Atkinson
,
A.
, 2003, “
Transport Properties of Solid Oxide Electrolyte Ceramics: A Brief Review
,”
Solid State Ionics
0167-2738,
174
(
1–4
), pp.
135
149
.
2.
Feighery
,
A. J.
, and
Irvine
,
J. T. S.
, 1999, “
Effect of Alumina Additions Upon Electrical Properties of 8mol.% Yttria-Stabilized Zirconia
,”
Solid State Ionics
0167-2738,
121
(
1–4
), pp.
209
216
.
3.
Porter
,
D. L.
, and
Heuer
,
A. H.
, 1979, “
Microstructural Development in Magnesia-Partially Stabilized Zirconia (Mg-PSZ)
,”
J. Am. Ceram. Soc.
0002-7820,
62
(
5–6
), pp.
298
305
.
4.
Minh
,
N. G.
, and
Takahashi
,
T.
, 1995,
Science and Technology of Ceramic Fuel Cells
,
Elsevier
,
Amsterdam
.
5.
Khor
,
K. A.
,
Chen
,
X. J.
,
Chan
,
S. H.
, and
Yu
,
L. G.
, 2004, “
Microstructure-Property Modifications in Plasma Sprayed 20wt.% Yttria Stabilized Zirconia Electrolyte by Spark Plasma Sintering (SPS) Technique
,”
Mater. Sci. Eng., A
0921-5093,
A366
(
1
), pp.
120
126
.
6.
Lv
,
Z. G.
,
Yao
,
P.
,
Guo
,
R. S.
, and
Dai
,
F. V.
, 2007, “
Study on Zirconia Solid Electrolytes Doped by Complex Additives
,”
Mater. Sci. Eng., A
0921-5093,
A458
(
1–2
), pp.
355
360
.
7.
de Ridder
,
M.
,
van Welzenis
,
R. G.
,
Brongersma
,
H. H.
, and
Kreissig
,
U.
, 2003, “
Oxygen Exchange and Diffusion in the Near Surface of Pure and Modified Yttria-Stabilised Zirconia
,”
Solid State Ionics
0167-2738,
158
(
1–2
), pp.
67
77
.
8.
Badwal
,
S. P. S.
, 1987, “
Effect of Dopant Concentration on Electrical Conductivity in the Scandia-Zirconia System
,”
J. Mater. Sci.
0022-2461,
22
(
11
), pp.
4125
4132
.
9.
Spiridonov
,
F. M.
,
Popova
,
L. N.
, and
Popil’skii
,
R. Ya.
, 1970, “
Phase Relations and the Electrical Conductivity in the System ZrO2–Sc2O3
,”
J. Solid State Chem.
0022-4596,
2
(
3
), pp.
430
438
.
10.
Politova
,
T. I.
, and
Irvine
,
J. T. S.
, 2004, “
Investigation of Scandia-Yttria-Zirconia System as an Electrolyte Material for Intermediate Temperature Fuel Cells: Influence of Yttria Content in System (Y2O3)x(Sc2O3)(11-x)(ZrO2)89
,”
Solid State Ionics
0167-2738,
168
(
1–2
), pp.
153
165
.
11.
Badwal
,
S. P. S.
,
Ciacchi
,
S. F.
,
Rajendran
,
S.
, and
Drennan
,
J.
, 1998, “
An Investigation of Conductivity, Microstructure and Stability of Electrolyte Compositions in the System 9mol% (Sc2O3–Y2O3)–ZrO2(Al2O3)
,”
Solid State Ionics
0167-2738,
109
(
3–4
), pp.
167
186
.
12.
Yamamoto
,
O.
,
Arachi
,
Y.
,
Takeda
,
Y.
,
Imanishi
,
N.
,
Mizutani
,
Y.
,
Kawai
,
M.
, and
Nakamura
,
Y.
, 1995, “
Electrical Conductivity of Stabilized Zirconia With Ytterbia and Scandia
,”
Solid State Ionics
0167-2738,
79
, pp.
137
142
.
13.
Arachi
,
Y.
,
Sakai
,
Y. M.
,
Yamamoto
,
Y.
,
Takeda
,
Y.
, and
Imanishi
,
N.
, 1999, “
Electrical Conductivity of the ZrO2-Ln2O3 (Ln=lanthanides) System
,”
Solid State Ionics
0167-2738,
121
(
1–4
), pp.
133
139
.
14.
Haering
,
C.
,
Roosen
,
A.
,
Schichl
,
H.
, and
Schnoeller
,
M.
, 2005, “
Degradation of the Electrical Conductivity in Stabilized Zirconia System. Part II: Scandia-Stabilized Zirconia
,”
Solid State Ionics
0167-2738,
176
(
3–4
), pp.
261
268
.
15.
Yamamura
,
H.
,
Utsunomiya
,
N.
,
Mori
,
T.
, and
Atake
,
T.
, 1998, “
Electrical Conductivity in the System ZrO2–Y2O3–Sc2O3
,”
Solid State Ionics
0167-2738,
107
(
3–4
), pp.
185
189
.
16.
Arachi
,
Y.
,
Asai
,
T.
,
Yamamoto
,
O.
,
Takeda
,
Y.
,
Imanishi
,
N.
,
Kawate
,
K.
, and
Tamakoshi
,
C.
, 2001, “
Electrical Conductivity of ZrO2–Sc2O3 Doped With HfO2, CeO2, and Ga2O3
,”
J. Electrochem. Soc.
0013-4651,
148
(
5
), pp.
A520
A523
.
17.
Chiba
,
R.
,
Yoshinura
,
F.
,
Yamaki
,
T.
,
Ishii
,
T.
,
Yonezawa
,
T.
, and
Endou
,
K.
, 1997, “
Ionic Conductivity and Morphology in Sc2O3 and Al2O3 Doped ZrO2 Films Prepared by the Sol-Gel Method
,”
Solid State Ionics
0167-2738,
104
(
3–4
), pp.
259
266
.
18.
Ishii
,
T.
, 1995, “
Structural Phase Transition and Ionic Conductivity in 0.88ZrO2-(0.12-x)Sc2O3-xAl2O3
,”
Solid State Ionics
0167-2738,
78
(
3–4
), pp.
333
338
.
19.
Yashima
,
M.
,
Kakihana
,
T.
, and
Yoshimura
,
M.
, 1996, “
Metastable-Stable Phase Diagrams in the Zirconia Containing Systems Utilized in Solid Oxide Fuel Cell Application
,”
Solid State Ionics
0167-2738,
86–88
(
2
), pp.
1131
1149
.
20.
Fujimori
,
H.
,
Yashima
,
M.
,
Kakihana
,
M.
, and
Yoshimura
,
M.
, 2002, “
The β-Cubic Phase Transition of Scandia-Doped Zirconia Solid Solution: Calorimetry, X-Ray Diffraction and Raman Scattering
,”
J. Appl. Phys.
0021-8979,
91
(
10
), pp.
6493
6498
.
21.
Hirano
,
M.
,
Oda
,
T.
,
Ukai
,
K.
, and
Mizutani
,
Y.
, 2002, “
Suppression of Rhombohedral Phase Appearance and Low Temperature Sintering of Scandia-Doped Cubic Zirconia
,”
J. Am. Ceram. Soc.
0002-7820,
85
(
5
), pp.
1336
1338
.
22.
Lei
,
Z.
, and
Zhu
,
Q.
, 2007, “
Phase Transformation and Low Temperature Sintering of Manganese Oxide and Scandia Co-Doped Zirconia
,”
Mater. Lett.
0167-577X,
61
(
6
), pp.
1311
1314
.
23.
Bastow
,
T. J.
,
Mathews
,
T.
, and
Sellar
,
T. R.
, 2004, “
Al2O3 Solubility in the Fast Ion Conductor 0.88 ZrO2-(0.12-x)Sc2 O3-x Al2O3 Determined by 27Al NMR
,”
Solid State Ionics
0167-2738,
175
(
1–4
), pp.
415
417
.
24.
Lee
,
D.-S.
,
Kim
,
W. S.
,
Choi
,
S. H.
,
Kim
,
J.
,
Lee
,
H. W.
, and
Lee
,
J.-H.
, 2005, “
Characterization of ZrO2 Co-Doped With Sc2O3 and CeO2 Electrolyte for the Application of Intermediate Temperature SOFCs
,”
Solid State Ionics
0167-2738,
176
(
9–10
), pp.
33
39
.
25.
Wang
,
Z.
,
Cheng
,
M.
,
Bi
,
Z.
,
Dong
,
Y.
,
Zhang
,
H.
,
Zhang
,
J.
,
Feng
,
Z.
, and
Li
,
C.
, 2005, “
Structure and Impedance of ZrO2 Doped With Sc2O3 and CeO2
,”
Mater. Lett.
0167-577X,
59
(
19–20
), pp.
2579
2582
.
26.
Zevalkink
,
A.
,
Hunter
,
A.
,
Swanson
,
M.
,
Johnson
,
C.
,
Kapat
,
J.
, and
Orlovskaya
,
N.
, 2007, “
Processing and Characterization of Sc2O3–CeO2–ZrO2 Electrolyte Based Intermediate Temperature Solid Oxide Fuel Cells
,”
Mater. Res. Soc. Symp. Proc.
0272-9172,
972
.
27.
Rosten
,
R.
,
Koski
,
M.
, and
Koppana
,
E.
, 2006, “
A Guide to the Calculation of Theoretical Densities of Crystal Structures for Solid Oxide Fuel Cells
,”
Journal of Undergraduate Materials Research
,
2
, pp.
38
41
.
28.
Chen
,
X. J.
,
Khor
,
K. A.
, and
Chan
,
S. H.
, 2005, “
Reducing Effect of Contaminants in Solid Oxide Fuel Cell Electrolyte by Spark Plasma Sintering
,”
Advances in Applied Ceramics
,
104
(
3
), pp.
117
122
.
29.
Lefevre
,
J.
, 1963, “
Some Structural Modifications of Fluorite-Type Phases in Systems Based on Zirconia or Hafnium Oxide
,”
Ann. Chim. (Paris)
0151-9107,
8
(
1–2
), pp.
117
149
.
30.
Wilkinson
,
A. J.
, and
Hirsch
,
P. B.
, 1997, “
Electron Diffraction Based Techniques in Scanning Electron Microscopy of Bulk Materials
,”
Micron
0968-4328,
28
(
4
), pp.
279
308
.
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