Thermal recrystallization of alpha-recoil damaged minerals of the pyrochlore structure type.

摘要

Thermal recrystallization effects (heat of recrystallization and identification of phases formed), have been determined for naturally occurring members of the pyrochlore group which have received alpha doses of up to 4 X 10 to the 16th power alphas/mg. The heats of recrystallization, E(sub t), range from 125 to 210 J/g. Release of energy decreases as a function of crystallinity (estimated on the basis of the intensity of x-ray diffraction maxima), with the fully-metamict samples approaching 210 J/g. Lower measured values (40-125 J/g) are the result of alteration of the pyrochlores. Other metamict, complex oxides with stoichiometries of ABO(sub 4) and AB(sub 2)O(sub 6) have lower heats of recrystallization (40-85 J/g), and are easily distinguished from pyrochlore group minerals. Activation energies of recrystallization, E(sub a), range between values of 0.29 to 0.97 eV, less than those measured for Pu-doped, synthetic zirconolites.