Direct synthesis of A2(Ti(1 − y)Zry)2O7 (A = Gd3+, Y3+) solid solutions by ball milling constituent oxides

Different compositions in two solid solutions, A2(Ti(1 − y)Zry)2O7 (A = Gd3+, Y3+), with high oxygen ion conductivity, have been successfully prepared at room temperature via mechano-chemical synthesis. Stoichiometric mixtures of the constituent oxides were milled in a planetary ball mill by using zirconia vials and balls. Chemical changes in the powder mixtures as a function of composition and milling time were followed by using X-ray diffraction showing that in all cases and after milling for 19 h, the powders consisted of a single phase. Powders were also examined by scanning electron microscopy (SEM) finding out that they basically consist of sub-micron size agglomerates and aggregates of nanoparticles.