Abstract: This paper investigated the effect of gelation speed on the surface fractal dimensions of silica xerogels derived from TEOS (actone
as solvent, catalyzed by HCl, pH≈3), and analyzed the influence caused by calcination. The results show that different gelation speeds hardly
affect the surface fractal dimensions of the xerogels without calcination, but the surface fractal dimensions of xerogel acquired with slower gelation
speed will decrease more after calcinated at 600℃. Generally, the surface fractal dimensions of calcinated silica xerogel can remaine almost
unchanged over 800℃.

Key words: gelation, xerogels, surface fractal dimension