High-temperature deformation of Sr(FeCo)1.5Ox ceramics Original Research Article

Compressive creep of polycrystalline SrFe1.2Co0.3Ox and SrFeCo0.5Ox ceramics has been investigated at 940–1000°C in constant-load and constant-displacement-rate experiments. At low stresses, the stress exponent was ≈1 and the activation energy was ≈110–135 kJ/mol. At higher stresses, a transition occurred and the stress exponent became ≈2.4–3.1 and the activation energy became ≈425–453 kJ/mol. At higher stresses, there was no dependence of the steady-state flow stress on oxygen partial pressure from 10–105 Pa. The creep parameters and scanning and transmission electron microscopy observations of the deformed samples suggested that deformation was controlled by diffusion at low stresses and dislocation glide at high stresses.