Mechanical characterization of copper coatings electrodeposited onto different substrates with and without ultrasound assistance

Abstract

The mechanical properties of systems consisting of copper coatings electrodeposited on both brass sheet (BS) and thick electrodeposited nickel coating (ED Ni) substrates have been investigated. The electrodeposition of copper coatings was performed with and without the ultrasound assistance. The ultrasound application decreases root mean square (RMS) roughness of deposited Cu coating on both applied substrates, as obtained from non-contact AFM measurement. The coating roughness is highly dependent on the substrate roughness, being the smallest for the Cu coatings deposited on ED Ni substrate with the ultrasound mixing. The hardness and adhesion properties were characterized using the Vickers microindentation test. Model of Korsunsky was applied to the experimental data for determination the film hardness and the model of Chen-Gao was used for the adhesion evaluation. The introduction of ultrasonic agitation caused the changes in the film microstructure, and consequently in the mechanical properties. The copper coatings on both substrates, have higher hardness when deposited from electrolyte with ultrasound agitation. Although the type of the substrate has the major influence on the adhesion strength, it can be said that Cu electrodeposition with ultrasonic mixing contributes to an increase in adhesion.