Effect of Co content on electrodeposition mechanism and mechanical properties of electrodeposited Ni-Co alloy
2016 (English)In: Transactions of Nonferrous Metals Society of China, ISSN 1003-6326, E-ISSN 2210-3384, Vol. 26, no 2, 484-491 p.Article in journal (Refereed) PublishedText
Ni-Co coatings with various cobalt contents were electrodeposited from modified Watts bath. The effect of cobalt content on electrodeposition mechanism of the coatings was studied by electro-chemical impedance spectroscopy method (EIS). Surface morphology and crystallographic structure of the coatings were investigated by means of SEM and XRD. Mechanical properties of the coatings were determined using Vickers microhardness and tensile tests. It was found that with increasing the Co2+ ions in electroplating bath, the charge transfer resistance (Rct) of Ni-Co film increased whereas the Warburg impedence decreased. This may be due to enhancement in coverage of cathode surface by Co(OH)2 and higher diffusion rate of metal ions towards cathode surface, respectively. Also, with increasing the cobalt content in the bath, cobalt content in the alloy coating increased anomalously and (111) texture consolidated gradually. With increasing the cobalt content up to 45% in alloy coating, the grain size decreased and consequently, hardness and strength of the alloy increased. Further enhancement of cobalt content up to 55% led to a little decrease in hardness and strength. The maximum ductility was observed for Ni-25%Co coating due to relatively small grain size and compact structure. © 2016 The Nonferrous Metals Society of China.
Place, publisher, year, edition, pages
2016. Vol. 26, no 2, 484-491 p.
electrodeposition, mechanical properties, microstructure, Ni-Co coating, Cathodes, Charge transfer, Coatings, Cobalt alloys, Corrosion, Electrodes, Grain size and shape, Hardness, Metal cladding, Metal ions, Metals, Nickel, Spectroscopic analysis, Tensile testing, Cathode surface, Charge transfer resistance, Compact structures, Crystallographic structure, Electrodeposition mechanism, Electroplating bath, Small grain size, Vickers microhardness, Cobalt
Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:hj:diva-30771DOI: 10.1016/S1003-6326(16)64136-5ISI: 000369696900019ScopusID: 2-s2.0-84963948581OAI: oai:DiVA.org:hj-30771DiVA: diva2:941188