| The sol-gel method starts from solutions, leading to formation
of dry gels, glasses and ceramics of different microstructures
through various transformations, such as solution
to sol, sol to wet gel, wet gel to dry gel and dry gel to glass
and ceramics. Various microstructures are formed during
the process of these transformations. The microstructure of
the product is controlled mainly by the type and content of
the catalyst, acid or base, although other processing conditions
may affect to some degree. In this article, control of
pore sizes of bulk silica gels and application of the silica gels
with controlled pore sizes are discussed. It is also shown that
glassy, randomly crystalline and crystal-oriented Li2B40 7
coating films can be prepared by controlling the composition
of the starting solution. |
