Zirconia ceramics, mainly of cubic phase, were used in different applications

because of their particular electrical and structural properties. After the forming

stage, sintering leads to a material with suitable microstructural characteristics. The

sintering process mainly depends on thermal cycle and on starting particle size and

its distribution; it also depends on density and the microstructure of green material.

Cubic zirconia has a high (2680C) melting temperature; however, effective

sintering could be observed above 900C (nanoparticles), and it may reach a final

density of 96–98% the theoretical value at relative low temperatures. The objective

of this paper was to study the sintering kinetics of stabilized zirconia in its cubic

phase with 8mol%Y2O3 under fast firing rates up to nearly isothermal conditions.

Samples were shaped from suspensions dispersed with ammonium polyacrylate by

slip casting. Sintering was performed at 1200C to 1400C. The sintering kinetic

process was followed by measuring density as a function of time. A sintering

model was applied to fit the experimental data of the first steps of densification. It

was observed that sintering obeys the same mechanism in the temperature and time

ranges under study, which results in an activation energy of 170kJ/mol. Sintering

was controlled by Zr cation diffusion, for which a lattice diffusion coefficient of 8

x 10−12cm2/s at 1400C was found, and the activation energy for the diffusion

process was 223kJ/mol.

Sintering Kinetics of 8Y–Cubic Zirconia: Cation Diffusion Coefficient. G.Suárez,

L.B.Garrido, E.F.Aglietti: Materials Chemistry and Physics, 2008, 110[2-3], 370-5