scholarly journals Nature of the Monoclinic to Cubic Phase Transition in the Fast Oxygen Ion Conductor La2Mo2O9(LAMOX)

2007 ◽  
Vol 129 (21) ◽  
pp. 6903-6907 ◽  
Author(s):  
Lorenzo Malavasi ◽  
HyunJeong Kim ◽  
Simon J. L. Billinge ◽  
Thomas Proffen ◽  
Cristina Tealdi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Cubic Phase ◽  
Ion Conductor ◽  
Oxygen Ion ◽  
Oxygen Ion Conductor

Phase Relations And Conductivity In ZrO2-Sc2O3-La2O3 System

1994 ◽  
Vol 346 ◽  
Author(s):  
Akihiko Yamaji ◽  
Takao Ishii ◽  
Masami Kanzaki
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Structural Transition ◽  
Ion Conductivity ◽  
Cubic Phase ◽  
Discontinuous Change ◽  
Ion Conductor ◽  
Oxygen Ion ◽  
Phase Stabilization ◽  
Oxygen Ion Conductor

ABSTRACTThe oxygen-ion conductor 0.88ZrO2-0.12Sc2O3 has a discontinuous change in ion conductivity at about 660°C. This change accompanies the structural transition from rhombohedral to cubic phase. Since the high temperature cubic phase shows large ion conductivity, it is of interest to examine whether or not the cubic phase stabilizes in the low temperature region by another dopant . By adding only 0.005 mole % La2O3, the cubic phase is stabilized below about 500 °C without any loss of conductivity compared with 0.88ZrO2-0.12Sc2O3. The ion conductivity of cubic stabilized ZrO2-Sc2O3-La2O3 system is around 1×10-1 S/cm at 800°C. Cubic phase stabilization using second dopant in a ZrO2-Sc2O3 system led to the finding of a fast oxygen-ion conductor in the ZrO2-Sc2O3-La2O3 system.

Influence of Fe Doping on the Oxygen-Ion Diffusion and Electrical Conduction of La1.95K0.05Mo2-XFexO9-δ

2010 ◽  
Vol 663-665 ◽  
pp. 506-510
Author(s):  
Chun Li ◽  
Da Li ◽  
Qian Feng Fang
Keyword(s):  
Phase Transition ◽  
Fe Doping ◽  
Conductivity Measurements ◽  
Ion Diffusion ◽  
Solid Reaction ◽  
Ion Conductor ◽  
Reaction Method ◽  
Oxygen Ion ◽  
Oxygen Ion Conductor ◽  
Oxygen Ion Diffusion

Based on the oxygen ion conductor La1.95K0.05Mo2O8.95, a series of Fe-doped samples La1.95K0.05Mo2-xFexO9- (x=0, 0.025, 0.05, 0.1) were prepared with conventional solid reaction method. The effects of Fe doping on the structure, oxygen ion diffusion and electrical conductivity were studied. Based on the results of conductivity measurements, it can be concluded that Fe doping can improve the conductivity obviously, and doping of both Fe and K samples have better conductivity, which successfully suppresses the phase transition.

Microstructure and Property Study of La2Mo1.5W0.5O9/Ag Composites

2010 ◽  
Vol 663-665 ◽  
pp. 620-624
Author(s):  
Chun Li ◽  
Da Li ◽  
Qian Feng Fang
Keyword(s):  
Solid State Reaction Method ◽  
Second Phase ◽  
Doping Amount ◽  
Conventional Solid State Reaction ◽  
Single Phase Sample ◽  
Ion Conductor ◽  
Oxygen Ion ◽  
Direct Current Conductivity ◽  
Oxygen Ion Conductor ◽  
Sample Density

Based on the oxygen ion conductor La2Mo1.5W0.5O9, a series of Ag2O doped samples La2Mo1.5W0.5O9/Ag were prepared with conventional solid-state reaction method. The effects of Ag2O doping on the microstructure and electrical conductivity have been investigated by XRD, FESEM and direct current conductivity measurements. With the increase of Ag2O doping, the grain was further refined and compacted, meanwhile, Ag diffusion distribution in the form of second-phase appear at grain boundary. The sample density and conductivity also gradually increased with the increasing of doping amount. The conductivity of the composite specimen La2Mo1.5W0.5O9 /Ag has a great enhancement when the concentration of Ag2O is around 27 wt%, which is eight times higher than that of the single-phase sample.

Activity of Bi2O3 in Bi2O3Y2O3 oxygen ion conductor

1992 ◽  
Vol 98 (1) ◽  
pp. 206-209 ◽  
Author(s):  
Keqin Huang ◽  
Changzhen Wang ◽  
Xiuguang Xu
Keyword(s):  
Ion Conductor ◽  
Oxygen Ion ◽  
Oxygen Ion Conductor

A Composite Ionic-Electronic Conductor in the (Ca,Sr,Ba)-Bi Oxide System

2000 ◽  
Vol 658 ◽  
Author(s):  
James K. Meen ◽  
Oya A. Gökçen ◽  
I-C. Lin ◽  
Karoline Müller ◽  
Binh Nguyen
Keyword(s):  
Polymorphic Transformation ◽  
Alkaline Earth ◽  
Binary Systems ◽  
Bulk Composition ◽  
Stability Limit ◽  
Rhombohedral Phase ◽  
Ion Conductor ◽  
Electronic Conductor ◽  
Oxygen Ion ◽  
Oxygen Ion Conductor

ABSTRACTThe rhombohedral alkaline earth-bismuth oxide phase, an oxygen ion conductor, does not coexist stably with electronic conductors in any of the three binary systems, Ca-Bi-O, Sr-Bi-O, Ba-Bi-O. A thermodynamically stable composite of a rhombohedral phase that contains Ba and Sr or Ca or both with the electronic conductor BaBiO3 may be synthesized. The rhombohedral phase appears to have complete mutual miscibility of the alkaline earth elements. The composi- tions of rhombohedral phase that coexist with BaBiO3 in the Sr-Ba-Bi ternary system and the Ca- Sr-Ba-Bi quaternary systems are described. The value of ionic conductivity of the rhombohedral phase (at a constant Bi: [Ca+Sr+Ba]) is not dependent on the relative amounts of Ca, Sr, and Ba. The temperature at which the rhombohedral phase undergoes a polymorphic transformation from a low-temperature (2) form that is a weak ion conductor to a high-temperature (β1) form that is a much better oxygen ion conductor. The temperatures of the polymorphic transformation and of the upper stability limit of the rhombohedral phase both depend strongly on Ca: Sr: Ba. The β1 form develops in the Ba-Bi system at the lowest temperatures and at the highest ones in the Ca- Bi system. On the other hand, the Ca-Bi phase has greater thermal stability than its Ba ana- logues. The temperature range over which a useful composite conductor can operate is, there- fore, strongly dependent upon the bulk composition of the system.

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