Browsing by Author "Cashio, JG"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Fe and Mg solubility in the Ca site of zirconolite, CaZrTi2O7
    (Australian Institute of Physics, 2004-02-04) Vance, ER; Cashio, JG; Hanna, JV; Garrett, Z; Bhati, M
    The solid solubility of Fe in the Ca site of zirconolite appears to be approximately the same whether it is incorporated as the divalent or trivalent species. Divalent Fe was encouraged by using an argon firing atmosphere and direct substitution in the Ca site [Ca(1-x)FexZrTi2O7] and trivalent Fe by the use of an air atmosphere and Al compensation in the Ti site [Ca(1-x)FexZrTi(2-x)AlxO7]. The anticipated valences were confirmed by X-ray near-edge, Xray photoelectron and Mossbauer spectroscopies. Changing the firing atmosphere from argon to air and vice versa also changed the Fe valences, but scanning electron microscopy showed that small amounts of second phase, Fe-bearing materials were present. The possible reasons for the apparently similar solid solubilities of divalent and trivalent Fe in the Ca site are discussed. Solid state magic-angle nuclear magnetic resonance was used to study Mg speciation in the Ca and Ti sites of zirconolite.