A new furnace design for use in combined X-ray absorption and diffraction of catalysis and ceramics studies: formation from carbonate precursors of Cu, Co, Mn spinels for the oxidation of CO and the formation of PLZT, a piezoelectric ceramic

In order to measure combined X-ray absorption fine structure, XAFS and X-ray diffraction, XRD in-situ on a sample, which is being heated in a furnace, there are a number of constraints on the furnace design due to the geometry of the detectors around the sample. We present a new furnace design which is based on a tube furnace: primarily for ceramics or catalysis research where the sample is heated in air, but at temperatures of up to 1200°C. The design and specifications of this furnace are presented. To demonstrate the use of the high temperature furnace we have chosen a system which contains three elements, Mn, Co and Cu, whose XAFS and XRD have been measured. The sample was heated in air to 600°C and the initial collapse of the crystalline carbonates was followed by the formation of the final spinel phase. Furthermore, the structural changes also accompany changes in the oxidation states, especially of Cu and Mn. The Cu and Mn in the final product is present as a mixture of Cu 1+ and 2+ and Mn as 3+ and 4+ oxidation states. The XAFS analysis of the data also yielded information about the local coordination changes during the transformation of the precursor carbonates to the final spinel product. We also show some preliminary data from the kinetics of formation of PLZT [Pb_0.92La_0.08(Zr_0.65Ti_0.35)_0.98O₃], from an amorphous gel to a crystalline phase material (ABO₃).