Application of Moessbauer Spectroscopy in Studies of Thermal Fatigue of Ceramic Materials. Part of a Coordinated Programme on Development of Methods for the Application of Moessbauer Spectroscopy in Mineralogy, Soil Sciences and Ceramics. Final Report for

摘要

Moessbauer measurements have been carried out on powder samples of pseudobrookite (Fe sub 2 TiO sub 5 ) which is known to exhibit extensive microcracking due to its highly anisotropic thermal expansion. The samples were subjected to temperature cycling treatment either at high (30 to 450 C) or low (-130 to 120 C) temperature range. It was observed that the crystal lattice vibrations are changing in response to the thermal fatigue treatment applied. Measurements of isomer shift and Moessbauer spectral areas allows to determine the characteristic Debye temperature which depends on the type of temperature treatment used, the findings are in qualitative agreement with the existence of a critical grain size for the microcracking of Fe sub 2 TiO sub 5 as found in elastic modules and flexural strength measurements. (Atomindex citation 12:587725)