Properties of electrodeposited silver–cobalt coatings

Abstract

Silver-cobalt coatings were elecrodeposited from cyanide-pyrophosphate electrolytes with and without additives (diammonium oxalate monohydrate and 2-Butyne-1,4-diol). The deposition rate, the alloy composition, as well as some physicomechanical (internal stress, microhardness, plug-in forces, abrasion resistance) and electrical properties (contact resistance, magnetoresistance) of the obtained coatings, depending upon the applied current density or the cobalt content, respectively, were investigated. The increase in current density led to the increase in the Co content of the coatings and to a decrease in the grain size of both silver and cobalt phases. Granular structural type of deposits with a magnetoresistance of about 4% ratio was shown. The tensile stress observed in pure Ag deposits increased in the presence of Co and with an increase in its content in the alloy. The increase in the microhardness, abrasion resistance and electrical resistance of the Ag-Co coatings depended almost linearly on the Co content. The performed high speed electroplating showed significant increase in the deposition rate and smoothness of the coatings.

The influence of substituted aromatic aldehydes on Zn-Mn alloy electrodeposition

“…28 Hence, the low oxygen percent in the coatings obtained with additives, probably means that the deposits were hydroxide-free, i.e., the hydrogen evolution process during alloy deposition is not fast enough to create alkaline media in the near-cathodic layer. 29 It could be concluded that the EDS analysis gives circumstantial, but strong evidence that the additives are hydrogen inhibitors in Zn-Mn electrodeposition.…”

A comparative study of silver electrodeposition from pyrophosphate-cyanide and high concentration cyanide electrolytes in the presence of brighteners

“…In anodic turn, the first anodic peak (A1) recorded at -0.48V indicates the formation of passive AgCN film and the area of this peak is increased very slightly with the addition of 0.5 g L −1 KCN. Nineva [40] also mentioned this peak. At the second anodic peak (A2) at ca.…”

“…The other type of electrolyte, pyrophosphate-cyanide, contains pyrophosphate buffer salt and metal-cyanide complex ion as a source of metal without free cyanide. It is also known as low cyanide concentration bath [16][17][18][19]. This type of bath has been researched especially in patent literature [20][21][22].…”

Coated and uncoated reinforcements metal matrix composites characteristics and applications – A critical review

“…The coatings of over 10% of Co have high tensile strength. Microhardness, abrasion resistance, and electrical resistance increase with more Co amount in the coating (Nineva et al, 2006). Bike et al (Baik, 2013) observed the improvement in fracture resistance when alumina is coated with cobalt in aluminium alloy matrix composites by suppressing the formation of interfacial reaction product Al 4 C. Cobalt-coated fibers have higher tensile strengths, and moduli also improve wettability (Baik, 2013;Kulkarni et al, 1979;Pourhosseini et al, 2018).…”