Influence of electrolyte type and agitation regimes on structural- mechanical performance of electrolytically deposited copper coatings on different cathodes

Abstract

Composite systems of electrodeposited 10 µm Cu coatings on Cu foils and 30 µm Cu coatings on brass foils were obtained in direct current regimes (DC) from electrolytes without/with additives. Different regimes of stirring electrolytes were investigated: stationary, magnetic, and ultrasonic. Also, multilayered Cu coating was successfully obtained by the electrodeposition with periodic ultrasonic/magnetic stirring of basic sulfate electrolyte. A bending test technique was used to assess the adhesive strength to the cathodes. Vickers indentation test machine was used for measuring composite hardness in the micro-range. The adhesion parameters named “the critical reduced depth” and “critical cycle number” for the Cu coatings proved suitable for assessing the adhesion behavior. Composite hardness models of Korsunsky and Chen-Gao were applied in order to calculate an intrinsic hardness of the coatings and for an assessment of adhesion performance. The corrosion resistance of the Cu coatings was investigated using the “static corrosion test.” A comparative study showed that the Cu coatings produced in ultrasonic agitation regime or in laminate form have better mechanical properties and better corrosion resistance. It has also been shown that Cu coatings synthesized from electrolyte with additives are structurally superior, but a “soft hardening effect” was observed.