CETMIC   05378
CENTRO DE TECNOLOGIA DE RECURSOS MINERALES Y CERAMICA
Unidad Ejecutora - UE
artículos
Título:
Sintering kinetics of 8Ycubic zirconia: Cation diffusion coefficient
Autor/es:
G. SUA´ REZA, L.B. GARRIDOB, E.F. AGLIETTI C,∗
Revista:
MATERIALS CHEMISTRY AND PHYSICS
Editorial:
Elsevier
Referencias:
Año: 2007
ISSN:
0254-0584
Resumen:
19 Mechanism
20 Diffusion coefficient
a b s t r a c t
Zirconia ceramics, mainly of cubic phase, are 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 (2680 ◦C)
melting temperature; however, effective sintering could be observed for temperatures higher than 900 ◦C
(nanoparticles), and it may reach a final density of 9698% the theoretical value at relative low temperatures.
The objective of this paper is to study the sintering kinetics of stabilized zirconia in its cubic phase
with 8% molar of Y2O3 under fast firing rates up to nearly isothermal conditions. Samples were shaped
from suspensions dispersed with ammonium polyacrylate by slip casting. Sinteringwas performed in the
temperature range between 1200 ◦C and 1400 ◦C. The sintering kinetic processwas 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 170 kJ mol−1. Sintering is controlled by Zr
cation diffusion, for which a lattice diffusion coefficient of Dl =8×10−12 cm2 s−1 at 1400 ◦Cwas found, and
the activation energy of the diffusion process was 223 kJ mol−1.
© 2008 Published by Elsevier