Deformation of electrodeposited gradient Co/Sn multilayered coatings under micro-pillar compression

Compositionally modulated multilayer (CMM) Co-Sn coating were successfully deposited with the help of electrodeposition on copper substrate. The coating microstructure was homogeneous, nanostructured in nature with smooth and distinct interfaces as confirmed by SEM and TEM investigation. In this study, micro-mechanical properties of such CMM Co-Sn coatings has been investigated by means of micro-pillar compression. Micro-mechanical properties of electro-deposited monolithic sole Co and sole Sn coatings was also investigated for comparison purpose. CMM Co-Sn coating shows high flow strength of about 330 MPa, which is about 1.2 and 5 times higher than that of sole Co and sole Sn coating, respectively. Such enhanced mechanical properties are the result of intermixing of several thin Co-Sn layers to form a single broad layer to accommodate deformation of material and to minimize system's energy as evident by detail transmission electron microscopy investigation on deformed micro-pillars.