Wear Behaviour of Cobalt-Hardened Gold Coatings Related To Internal Macro-Stresses

Pulse electrodeposition of Ni/nano-TiO2 composites: effect of pulse frequency on deposits properties

“…Indeed, in our experimental set-up and at the highest applied frequency, we have observed a high instantaneous current spike induced at the beginning of the T on period-instead of a regular rectangular pulse-followed by a decrease towards a limiting value of peak current density (J p ). This is in accordance with previous results regarding codeposition of submicron alumina particles (0.05 lm) in Au-Co matrix under the same pulse plating conditions [31]. Thus, the higher overvoltage at 1,000 Hz could also result in the enhanced embedding rate of TiO 2 nanoparticles in the nickel matrix.…”

“…1). Under specific electrolysis conditions (pH, J) an analogous increment of codeposition percentage with increasing pulse frequency has been observed for Ni/ Al 2 O 3 composite coatings [22,31], although contradictory conclusions also exist in literature [21,32]. Therefore, to elucidate the correlation between pulse frequency and codeposition percentage, this study covers an extended range of pulse frequencies and electrodeposition parameters.…”

Significance of inclusions in electroplated gold films for electronics applications

“…Clearly, ductility alone does not determine wear resistance. On the other hand, the relevance of internal stress to wear resistance was pointed out by Celis et al (58). They found that the internal stress of CoHG varies as a function of metallic Co content, and noted that wear resistant deposits were obtained at the metallic Co content in the range of 0.05 to 0.1 wt%, where the internal stress ranged from 100 to 250 N mm -2 .…”

“…Two bulk properties have been proposed in the literature to be relevant to wear resistance: ductility (57) and internal stress (58). Antler (57) noted that AFHG has a ductility of 2-3% in terms of percentage elongation as compared to less than 0.4% for CoHG.…”