X-ray diffraction investigations of the thermal expansion of iron borate FeBO3 crystals

Abstract

The lattice parameters a, c of iron borate FeBO3 polycrystals have been measured in the temperature range 25–600°C by the X-ray diffraction method. The thermal expansion coefficients α are calculated from the measured values of the parameters. A substantial anisotropy of the thermal expansion is found. It is shown that the thermal expansion coefficient αc along the c axis is greater than the thermal expansion coefficient αa in a plane perpendicular to this axis. By X-ray peak profile analysisthe crystallite size was estimated from Scherrer’s formula. We have also investigated the temperature dependence of crystallite size in FeBO3.