Effect of the Isotopic Composition of Fe on Its Linear Thermal Expansion Coefficient.

The linear thermal expansion coefficients (LTECs) of isotopically natural Fe (natFe) and samples isotopically enriched in 56Fe (99.945 wt %) and 57Fe (90.954 wt %) have been determined as functions of temperature by X-ray diffraction dilatometry in the temperature range 173–433 K. The low-temperature LTEC of 57Fe has been shown to be larger. As the temperature is raised to the range 368–433 K, the difference between the LTECs of the samples differing in isotopic composition decreases. [ABSTRACT FROM AUTHOR]