Effect of process parameters on electroless plating membrane characteristics

In this article we address the process perspective of electroless plating technique to fabricate nickel-ceramic composite membranes. In this work, we also report an inexpensive ceramic membrane precursor formulation which upon sintering process yielded a membrane support with an average pore size of 275 nm. Subsequently, membranes were subjected to electroless plating for wide choice of nickel solution concentration (0.04-0.16 mol/L) and loading ratio (defined as membrane area per unit plating solution volume) values (196-393 cm(2)/L). Various parameters evaluated to relate upon plating and membrane characteristics are conversion, plating efficiency and inefficiency, metal layer thickness and average nickel-ceramic membrane pore size. In general it was observed that sodium hypophosphite based electroless nickel baths provided lower conversion (10-40%) and moderately higher efficiencies (90-60%). However, the effect of loading ratio on efficiency was found to be insignificant. On the other hand, membrane densification was observed to vary between 78-90% to yield a surface pore size reduction from 275 nm to 128-90 nm. Retail cost based analysis further indicates the non-linear dependencies of both chemicals cost and metal layer thickness with respect to the percent pore densification values. (C) 2010 Elsevier B.V. All rights reserved.