Deformational structural transition under aluminium and its alloys high-temperature loading

AbstractWe report x-ray scattering studies of polarons and tilt ordering in the high-temperature, paramagnetic insulating phase of La0.7Ca0.3MnO3. The temperature dependence of scattering due to individual and correlated polarons was measured, and the latter was found to disappear at ∼400 K. The scattering due to tilt ordering, which was observed by tuning the incident photon energy near the La L1 edge, was also measured as a function of temperature. The destruction of tilt ordering at ∼690 K is believed to be associated with the orthorhombic-rhombohedral structural transition.

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Characterization and Applications of Calcium Ferrites Based Materials Containing Active Oxygen Species

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.45.2169 ◽

2006 ◽

Vol 45 ◽

pp. 2169-2175 ◽

Cited By ~ 15

Author(s):

Daisuke Hirabayashi ◽

Takeshi Yoshikawa ◽

Yoshiki Kawamoto ◽

Kazuhiro Mochizuki ◽

Kenzi Suzuki

Keyword(s):

High Temperature ◽

Structural Transition ◽

Active Oxygen Species ◽

Active Oxygen ◽

Calcium Ferrite ◽

Methane Partial Oxidation ◽

Oxygen Species ◽

Calcium Ferrites ◽

Oxide Ions ◽

Oxidation Mechanisms

Characterization and application of calcium ferrites based solid solutions containing active oxygen species for catalysts in propylene total and methane partial oxidation has been studied. The calcium ferrite based solutions containing brownmillerite phases showed a structural transition based on the migration of oxide ions at high temperature. The calcium ferrite solution provided two types of active oxygen species due to the existence of the brownmillerite phase. These oxygen species individually played important roles in the propylene and methane oxidation mechanisms.

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Structure Transition and Electrocaloric Effect of Pb(Zr1-xTix)O3 at High Field

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.432.3 ◽

2013 ◽

Vol 432 ◽

pp. 3-6

Author(s):

Wen Jiang Feng ◽

Zhi Guo Zhang ◽

Chuang Wu ◽

Hao Chen

Keyword(s):

High Temperature ◽

Transition Temperature ◽

Electric Field ◽

High Field ◽

Structural Transition ◽

Strong Electric Field ◽

Zero Field ◽

Electrocaloric Effect ◽

Structure Transition ◽

First Order

We investigated the structure transition and the electrocaloric effect in PbZr1-xTixO3 (PZT) with x=0.7, 0.8 and 0.9. The results show that 50 MV/m can make the structural transition be a continuous one. When x=0.7, 0.8 and 0.9 at the zero field, the first order structural transition occurs at T0=685, 687, and 698 K, respectively. Upon a strong electric field, the first order structural transition comes to the second one, which leads to lower the change of specific heat. The structural transition temperature is shifted at high temperature with increasing electric field. The maximum electrocaloric effect is present occurs at about 200 K above the corresponding Curie temperature. With increasing composition of Ti, the electrocaloric effect is enlarged, together with increasing structure transition temperatures.

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Phase Relations And Conductivity In ZrO2-Sc2O3-La2O3 System

MRS Proceedings ◽

10.1557/proc-346-335 ◽

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.

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Evidence for a Structural Transition to a Superprotonic CsH2PO4 Phase Under High Pressure

MRS Proceedings ◽

10.1557/proc-0929-ii02-01 ◽

2006 ◽

Vol 929 ◽

Author(s):

Cristian E. Botez ◽

Russell R. Chianelli ◽

Jianzhong Zhang ◽

Jiang Qian ◽

Yusheng Zhao ◽

...

Keyword(s):

High Pressure ◽

High Temperature ◽

Structural Transition ◽

Heating Temperature ◽

Ambient Pressure ◽

High Temperature Phase ◽

Cubic Phase ◽

Dihydrogen Phosphate ◽

Temperature Phase ◽

Ambient Conditions

ABSTRACTWe have used synchrotron X-ray powder diffraction (SXRPD) to investigate the structural behavior of cesium dihydrogen phosphate upon heating. Temperature-resolved data collected at ambient-pressure demonstrate that a transition from the room-temperature monoclinic phase (P21/m; a=7.90Å, b=6.39Å, c=4.87Å, and β=107.64°) to a high-temperature cubic phase (Pm3m; a=4.96Å) occurs at T=237°C. The high-temperature phase is not stable under ambient-pressure conditions, even in the absence of further heating. On the other hand, SXRPD measurements carried out under high-pressure (∼1GPa) evidence a transition from monoclinic to a stable cubic phase (Pm3m, a=4.88Å) at a temperature within the 255°C-275°C range. A 1000-fold increase in the proton conductivity (indicating the transition to the superprotonic phase) was previously observed under the same non-ambient conditions. Therefore, our results represent strong evidence that the superprotonic behavior in cesium dihydrogen phosphate is associated with a monoclinic-to-cubic polymorphic structural transition and not with chemical modifications.

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