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-Sch errer geometry for performing high temperature x-ray powder diffraction wit h synchrotron radiation at medium and high energies (35-100 keV). The furna ce has a maximum operating temperature of 1800 K with a variety of atmosphe res including oxidizing, inert, and reducing. The capability for sample rot ation, to ensure powder averaging, has been built into the design without c ompromising 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 prese nted. Time-resolved data on the orthorhombic to rhombohedral solid state ph ase transformation of SrCO3 is demonstrated using image plates. Rietveld re finable spectra, collected in as little as 8 s, opens the possibility of pe rforming time-resolved structural refinements of phase transformations. (C) 1999 American Institute of Physics. [S0034-6748(99)00309-3].