Influence of seeding on the crystallization kinetics of air-calcined Y-TZP gel-derived precursors

Yttria-doped tetragonal zirconia (Y-TZP, 3 mol% Y2O3) amorphous precursors seeded with nanometric Y-TZP particles (5 to 10 wt%) were prepared by the sol-precipitation method. Solid-state reactions occurring during heating were studied by differential thermal analysis and X-ray diffraction. It was found that the seeding of Y-TZP amorphous precursors with 5 to 10 wt% crystalline Y-TZP nanometric particles considerably lowered the onset of the Y-TZP solid solution crystallization temperature by nucleation and epitaxial growth. Thus, a complete Y-TZP solid solution was formed in the temperature range of 320–350 °C in air after a heat treatment for 20 h. The seeded Y-TZP precursors exhibited enhanced crystallization kinetics (about one order of magnitude higher), and the activation energy for the Y-TZP solid solution crystallization was reduced from 184 to 119 kJ/mol.