New high temperature furnace for structure refinement by powder diffraction in controlled atmospheres using synchrotron radiation

A low thermal gradient furnace design is described which utilizes Debye-Scherrer geometry for performing high temperature x-ray powder diffraction with synchrotron radiation at medium and high energies (35-100 keV). The furnace has a maximum operating temperature of 1800 K with a variety of atmospheres including oxidizing, inert, and reducing. The capability for sample rotation, to ensure powder averaging, has been built into the design without compromising thermal stability or atmosphere control. The ability to perform high-resolution Rietveld refinement on data obtained at high temperatures has been demonstrated, and data collected on standard Al2O3 powder is presented. Time-resolved data on the orthorhombic to rhombohedral solid state phase transformation of SrCO3 is demonstrated using image plates. Rietveld refinable spectra, collected in as little as 8 s, opens the possibility of performing time-resolved structural refinements of phase transformations. (C) 1999 American Institute of Physics. [S0034-6748(99)00309-3].