2023 Volume 41 Issue 4 Pages 337-347
The morphology, microstructure, hardness change, and co-deposition mechanism of electrolytic Ni–metal sputtered cellulose composite plating were investigated. Composite plating experiments were conducted using various cellulose powders as co-deposited materials, including natural wood derived cellulose (CF), sodium carboxymethyl cellulose (CMC), and those treated with Au-Pd sputtering (AP CF and AP CMC, respectively). It was found that cellulose composite Ni plated films are successfully fabricated with AP CF, CMC and AP CMC, while CF does not almost achieve co-deposition. Ni plated films with CMC and AP CMC showed approximately twice the surface Vickers hardness compared to the Ni film without cellulose. In contrast, Ni plated films with CF and AP CF showed similar hardness to that without cellulose. At cross-section of the specimen with AP CF, co-deposited sites where AP CF is fully covered with nickel with gold presence were observed. This suggests that Ni deposition from metal particles on AP CF surface forms co-deposition with “cladding” mode. On the other hand, the specimen with AP CMC showed that the cellulose as if pierced the Ni film as seen in that with CMC. This indicates that the Ni deposition mechanism via chelate complexes between carboxylate of CMC and Ni ions is dominant, and the effect of Au-Pd sputtering is negligible. Although Au–Pd sputtering treatment on the cellulose is effective in enabling co-deposition, such as with CF, it is not always necessary for cellulose co-deposition. The presence of conductive particles that act as a nucleus for Ni deposition is probably sufficient for co-deposition. This indicates potential that various types of the conductive cellulose are able to be applied as co-deposited materials for composite plating for such as the wear resistance coatings or the surface treatment on electrodes of electronic substrates.
