precipitation

in sol-gel processing
Sedimentation of a solid material (a precipitate) from a liquid solution in which the material is present in amounts greater than its solubility in the liquid.
Note:
When precipitation occurs in sol-gel processing, sol particles have aggregated to a size where gravitational forces cause them to sink or float. Generally, aggregation arises from a change in the sol that reduces the interparticle repulsion.
Source:
PAC, 2007, 79, 1801 (Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials (IUPAC Recommendations 2007)) on page 1824