Temperature Correction for Ceramic Powder X-ray Diffraction at a Higher Temperature

摘要

For powder XRD measurement at a higher temperature, there is a great difference (Δ_T) between the temperature (T) detected by a thermocouple in a specimen stage and the actual temperature (T_a) of the ceramic powder surface irradiated by X-ray. The BaTiO_3 ceramic powder was employed to make an temperature correction on heating in light of the change of the ～ 45° characteristic peak in the vicinity of its tetragonal-cubic phase transition point (T_C = 130°C). The thermal relaxation of BaTiO_3 is considered. When the BaTiO_3 ceramic powder was measured at T_C, the phase transition occurred at T = 170°C and Δ_T was determined as 40°C, which is 10°C higher than that of the ceramic bulk. The error of temperature correction is less than ± 3°C at T_C. The approximation of a linear dependency T_a - T was given as a temperature correction line between 25 and 130°C (T_a here).