Room Temperature Ferroelastic Creep Behavior of Porous (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ

Barbara Arnauda,Wakako Araki,Viviana Meruane,Ali Akbari-Fakhrabadi,Nina Orlovskaya

doi:10.3390/pr8111346

Barbara Arnauda, Wakako Araki + Show 3 more

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https://doi.org/10.3390/pr8111346

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Abstract

The time-dependent deformation of porous (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ (LSCF) under constant uniaxial compressive stress at room temperature has been studied. Both axial and lateral stress–strain deformation curves clearly show the non-linear ferroelastic behavior of LSCF perovskite during compression. The ferroelastic characteristics of deformation curves such as coercive stress and apparent loading moduli decrease when the porosity of the samples increases. Ferroelastic creep deformations at applied stresses of 25 and 50 MPa demonstrate that stress and porosity are influencing factors on creep deformation, which increases with increasing stress and porosity. A negative creep or axial expansion and lateral contraction were observed in the sample with 35% porosity under 50-MPa constant compression stress.

Highlights

Ternary oxide ceramics with ABO3 perovskite structures attract the scientific community due to their unique properties which depend on a number of different parameters such as a possibility of modifying their compositions by doping both on the A- and B-site of cations sub-lattice of the perovskites [1]
LaCoO3 -based perovskites possess a cubic symmetry during high-temperature processing and this cubic structure transforms to low symmetry phases such as rhombohedral upon cooling [4]
The low symmetry of the transformed phase leads to the formation of twins in alternating patterns to release stresses related with transformation strains [5,6]

Summary

Introduction

Ternary oxide ceramics with ABO3 perovskite structures attract the scientific community due to their unique properties which depend on a number of different parameters such as a possibility of modifying their compositions by doping both on the A- and B-site of cations sub-lattice of the perovskites [1]. Where α is the coefficient of thermal expansion of the material at temperature T0 which is the sample temperature at the start time of holding at maximum stress and εc is ferroelastic creep which can be described by a Prony series as

Results

Conclusion