Method for reducing the pore size of sintered metal filters by application of an alcoholic solution of a metal alkoxide which is converted to an insoluble hydrous metal oxide

摘要

The invention is a process for modifying pore size near the surface of porous materials. The surface is contacted with an alcohol solution of a metal alkoxide which forms a hydrous oxide insoluble in water, an amount of water insufficient to hydrolyze fully the metal alkoxide, and a mineral acid for a time sufficient for the solution to penetrate the surface region but not the bulk. This is followed by exposing to sufficient moisture to complete hydrolysis and then curing to stabilize the metal oxide in the pores near the surface.