Multiscale analysis of enclosed nickel metal layer constructed via a palladium-triggered autocatalytic reaction on aramid fiber surfaces

Abstract

Conductive aramid fibers have been attracting great interest owing to their lightweight, flexibility and metal-specific properties. Revealing the actual growth process of electroless nickel plating on the surface of aramid fibers is conducive to better control the quality of the prepared metal layer. Herein, we have fabricated different samples using the sensitization-activation two-step method and electroless nickel plating. Chemical element and valence analysis confirmed that the Pd, Ni and P uniformly attached to the surface of aramid fibers have zero valence. The chemical phase analysis and microstructure characterization demonstrated that the NiP alloy layer was amorphous as a whole, whereas Pd and Ni were the crystals with the characteristics of face-centered cubic crystals, and both of them could play a catalytic role in the redox reaction of electroless nickel plating. Furthermore, the possible mechanism of NiP growth on the surface of aramid fibers was proposed, which included the principle of closed assembly of the metal layer and three stages of ‘initial growth, high-speed growth and leveling’.