Journal of Applied Electrochemistry, Vol.41, No.12, 1397-1406, 2011
Properties of electrodeposited silver-cobalt coatings
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.