ENTHALPY OF CRYSTALLIZATION OF RARE-EARTH TITANATES FROM AMORPHOUS COPRECIPITATED HYDROXIDES

摘要

The crystallization of the pyrochlore-structure titanates R_2Ti_2O_7(R=Sm,Eu,Gd,Tb,Ho,Er,Tm) from x-ray amorphous coprecipitated hydroxides was studied by calorimetry and x-ray diffraction. The enthalpies and temperatures of crystallization were determined. The plot of the enthalpy of crystallization versus the atomic number of rare earth shows a well-defined break near gadolinium.