Wetness-impregnation

Dry impregnation, wet impregnation, successive impregnation, powder impregnation, preformed carrier impregnation... 

B. Nickel-Silica Catalyst It was prepared by impregnating wet silica gel with nickel nitrate solution, drying the mass, and decomposing the nitrate to the oxide at 350-400°. It was subsequently reduced in a stream of hydrogen at 300-350°. 

A number of methods have been reported in the literature for improving the thermal stability of acrylic fibers. For example, impregnating wet-spun fibers in the gel state with salts of metals from group II in the periodic table of the elements [496] or sodium sulfide solution [487] have been reported. Also, dried fiber can be impregnated with sulfuric acid solutions of formamide [488], phosphates or borax [489], or organotin salts [490]. 

There are at least two problems in impregnating wet materials. First, water is a mechanical obstacle for permeation of the organic composition into the volume of the materied. Second, water impedes the wetting of the surface of the pores of the material by the composition. If a water film exists between the cured composition and the solid, the strengthening effect of the impregnation will be minimal. 

---