High-temperature mechanical behavior of the solid-state electrolyte: La0.8Sr0.2Ga0..85Mg0.15O2.825

The creep behavior of fine-grained La0.8Sr0.2Ga0.85Mg0.15O2.825 (LSGM-2015) was investigated over the temperature: range 1200 to 1300 degrees C in air . The bi ief creep transients, value of the stress exponent close to unity, absence of deformation-induced dislocations, and lack of grain-shape chang e due to deformation suggest that the creep behavior of LSGM-2015 is contro lled by grain boundary sliding accommodated by diffusion. The value of the grain-size exponent close to two indicates that the late-controlling step i s lattice diffusion. A comparison of the activation energy for creep with a ctivation energies determined by ionic conductivity, oxygen tracer diffusio n, and theoretical predictions reveal that the creep rate of LSGM-2015 is c ontrolled by cation lattice diffusion. (C) 2000 The Electrochemical Society . S0013-4651(99)11-001-2. All rights reserved.