Micromechanical properties of anomalously electrodeposited nanocrystalline Nickel-Cobalt alloys: a review

Influence of Bath Hydrodynamics on the Micromechanical Properties of Electrodeposited Nickel-Cobalt Alloys

“…As reported earlier in our review paper [14], when all other ECD operating conditions are constant, the value of d A increased with increasing mass transport (e.g., by BHD) of the less noble species, i.e., Co 2+ , towards the WE surface. The eNiCo samples electrodeposited with varying BHD conditions (Section 4.1) were characterized by XRF to measure the respective Co A content as listed in Table 2.…”

“…Therefore, owing to their excellent micromechanical, tribological, and magnetic properties, the electrochemically deposited nickel-cobalt (eNiCo) alloys have gathered special attention of the research community in the recent decades as a promising candidate for the generation of microstructures for micromechanical applications. This is further evident by series of review papers from the year 2019 by authors of this paper [14] and Karimzadeh et al [9], in the year 2020 by Mbugua et al [15] and Safavi et al [16], and very recently in 2021 by Omar et al [17], all of which comprehensively described the current and prospective applications of eNiCo alloys.…”

“…The majority of research groups have attributed the excellent micromechanical properties of eNiCo alloys, additionally to their alloy composition, i.e., the solid solution strengthening effect, to their nanocrystalline (nC) microstructure, wherein the materials with grain size < 100 nm are categorized as nC-materials [ 18 , 19 , 20 ]. For, e.g., comparing two eNiCo alloys with similar alloy composition, the alloy with finer grain size possesses higher microhardness values [ 14 ]; i.e., complying with the Hall–Petch relation [ 21 ]. Here, the higher grain boundary area hinders the dislocation movement to a higher extent when compared to the coarse-grained materials, thereby enhancing the micromechanical and tribological properties [ 18 , 22 ].…”

“…The influence of some ECD conditions, such as electrolyte metal content, applied current density, bath additives as grain refiners, pulse plating, and pulse reverse plating on the resultant grain size for the fabrication of nC-eNiCo alloys is summarized in our previous review paper [ 14 ]. From the comprehensive review, it was found that the electrolyte cobalt content (Co E ), organic bath additives, applied current density, pulse plating deposition mode, and the electrolyte flow rate tend to have an influence on the grain size (i.e., they influence the nucleation and growth kinetics).…”

“…However, a model-based correlation of the ECD operating conditions with the resultant microstructural properties was missing. Additionally, contradictory results among the research findings were found, which could be attributed to the intricate correlation of the eNiCo alloy system with the ECD operating conditions [ 14 ]. Additionally, the influence of bath hydrodynamics (BHD) on the nucleation, growth kinetics, and micromechanical properties of eNiCo alloys was found to be the least investigated parameter.…”