Electroless plating on the surface of kapok fibres: analysis of an effective palladium-free nickel salt activation process

A two-step, palladium-free, nickel salt activation process was tested on kapok fibres (KF). The results showed that the ratio of the concentration of hydrogen ions to the concentration of hydroxide ions ([H+]/[OH-]) in the activation bath needs to be controlled within a range to achieve an optimal outcome. The final amount of deposited active Ni is not only dictated by [NiSO4 center dot 6H(2)O] but also dependent on the concentration of the reducing agent, [NaBH4], whose proper value is complicated by its self-decomposition reaction that can be catalysed by the active Ni and H+ ions. The concentration of NiSO4 employed needs to be capped to attain reasonable mass density and high electrical conductivity as required by light-weight electromagnetic interference shielding materials. An effective activation bath was formulated and experimentally confirmed to successfully initiate and sustain such an electroless plating process and a compact, uniform and amorphous Ni-P layer was formed on the KF surface.