Defect microstructures of Zr-dissolved TiO2 polycrystals, homogenized as rutile structure at 1600C and then aged at 900C for 2 to 200h in air, were characterized by analytical electron microscopy. Diffuse diffraction occurred at 1/2(211) as a result of Zr4+ substitution for Ti4+ with volume/charge compensating defect clusters. Upon annealing at 900C, plate-like Guinier-Preston zones appeared with the plate surface parallel to (100) and (010) and in association with dislocations. Commensurate superstructures with apparent triple {101} and {111} periodicity also occurred as metastable intermediates, which were presumably the precursor of the equilibrium ZrTi2O6 precipitate.

Defect Microstructures of TiO2 Rutile due to Zr4+ Dissolution and Expulsion. Yang, K.C., Shen, P., Gan, D.: Journal of Solid State Chemistry, 2006, 179[11], 3478-83