Investigation of the influence of the concentrations of Sn in electrochemically deposited CuSn alloy films on their mechanical properties

Mechanical properties of thin CuSn alloy films containing different content of Sn (0.06 – 67.5 wt.%) were investigated by means of nanoindentation experiments, using Nanoindenter G200 (Agilent Technologies), equipped with Berkovich indenter tip. The films were electrochemically deposited on screen-intermediate Ni film with thickness about 3 µm electrodeposited on Cu or brass (Cu66Zn34) substrates with thickness respectively 300 µm and 500 µm. The thicknesses of investigated CuSn films varied from 0.138 to 5.47 µm. Mechanical properties of the Cu and brass substrates were investigated too. As a result of nanoindentation experiments, load–displacement curves were obtained and two mechanical characteristics of the substrate and investigated films – indentation hardness (HIT) and indentation modulus (EIT) – were calculated using Oliver & Pharr approximation method. Dependence of indentation modulus and indentation hardness on the depth of indentation, content of Sn, structure and phase composition of the alloy films was investigated and discussed.