Suspension impregnation method, nickel

Early work on the use of foams and mats has been reviewed [9j. Nickel fiber, nickel-plated steel fiber, or nickel-plated graphite fiber mats are preferred because they have smaller pores ( 50(im) [14]. The most recently developed mats can have porosities as high as 95% [13] and are much lighter than the sintered nickel plaques, which typically have porosities between 80 and 90%. Initially, standard cathodic impregnation methods were used to load the active material into the foam [9]. More recently, the preferred method is to incorporate the Ni(OH)2 in the form of a slurry into the mat [13, 14]. This has been called the suspension impregnation method [14]. Considerable improvement in the Ni(OH)2 has been achieved by the addition of divalent Co compounds to the slurry. The best results... 

Reduction is the most common technique to prepare polymer-immobilized nanoparticles. Two different types of reduction can be considered. The first type, or the impregnation method, consists of the chemical reduction of metals from solutions or suspensions of their salts. Ammoniacal solutions of Cu, Cr, and Ag hydroxides are often used. Electrochemical or radiation-induced reduction in the presence of macroligands have also been employed. The reduction of mononuclear metal complexes chemically bound with polymers represent the second type. The impregnation method is more widely applied because it better meets the needs of catalysis. In particular, metal blacks, ultradispersed powders, etc. are prepared. For example, Raney nickel is stabilized by incorporating it into the silicone rubber "" followed by vulcanization at room temperature. 

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