The crytallite and pore-size evolution during isothermal sintering (40
0 less than or equal to T less than or equal to 700 degrees C) of SnO2
xerogels was studied by X-ray line broadening and nitrogen adsorption
-desorption isotherms. The experimental results show a strong anisotro
py of crystallite growth between [110] and [101] directions. The prefe
rential growth at [101] is followed by an increase in the mean pore si
ze, reduction of the specific surface area and invariance of total por
e volume. This behaviour is typical of grain coalescence sintering. Th
e kinetic analysis of experimental results suggests that the crystalli
te coalescence at [101] is governed by lattice diffusion. The strong a
nisotropy of the growth causes pore-size distribution broadening, hind
ering the macroscopic shrinkage of the compact during sintering.