Morphology and Microstructure of Annealed Ni-Co Alloy Powders Electrodeposited on Copper Substrates

Author(s)
Lidija Rafailovic, Aleksa M. Maricic, Werner Artner, Gerhard E. Nauer, Dragica M. Minic
Abstract

Nickel and cobalt alloy powders from two different electrolyte compositions were obtained by electrodeposition from an ammonium sulfate solution. The structure of Ni-Co deposits formed by electrodeposition at a galvanostatic regime and the influence of current density and the bath composition were studied by SEM, DSC and X-ray diffraction methods. It was shown that the microstructure and morphology of the powders depended on the deposition current density as well as bath composition. Both, bath composition and current density affect strongly the deposit growth mechanism and the deposit composition, microstructure, grain size and surface morphology. It was found that the overpotential significantly affects the structure of the formed deposits. When electrodeposition was performed far from equilibrium conditions face-centered cubic (FCC) cobalt was deposited while at low overpotential hexagonal close packed (HCP) Co was formed with a lower rate of hydrogen evolution. The increase of HCP phase in the nanocrystalline deposits was caused by increase of the Co content in the powder as well by decrease of the deposition current density. It was shown that the powders change their structure in the temperature interval from 300°C to 600°C. In Co rich samples, structural changes during heating were attributed to the phase transformation of HCP to FCC.

Organisation(s)
Physics of Nanostructured Materials
External organisation(s)
Kompetenzzentrum für elektrochemische Oberflächentechnologie GmbH , University of Belgrade
Journal
SCIENCE OF SINTERING
Volume
41
Pages
135-142
No. of pages
8
ISSN
0350-820X
DOI
https://doi.org/10.2298/SOS0902135R
Publication date
2009
Peer reviewed
Yes
Austrian Fields of Science 2012
103023 Polymer physics, 210006 Nanotechnology, 103018 Materials physics
Portal url
https://ucris.univie.ac.at/portal/en/publications/morphology-and-microstructure-of-annealed-nico-alloy-powders-electrodeposited-on-copper-substrates(ae3c4864-3e6c-4f78-8f8d-8565373d3096).html