In situ high temperature powder x-ray diffraction technique using a sapphire single-crystal flat cell.

This article focuses on the development of an in situ high-temperature x-ray diffraction (XRD) system at the BL02B2 beamline in SPring-8, designed to analyze powdered materials under various gas atmospheres, including vacuum, air, inert gases, and reduction gases. A novel sample cell made of single-crystal sapphire was created to enable XRD measurements above 1000 °C with short sample exchange times, improved temperature uniformity, and chemical stability. The system integrates a TS1500 heating stage with remote gas-pressure control and exhaust gas analysis tools (gas chromatograph and mass spectrometer) to simultaneously monitor phase changes and gas composition during high-temperature reactions. Demonstrations included observing the reduction of iron oxides, phase transitions of ZrO2 and BaCO3, and the synthesis of BaZrO3, confirming the system’s capability for in situ studies of functional materials under controlled atmospheres.