Failure analysis by indentation test of electrodeposited nanocrystalline CO-W and FE-W thin films

Abstract

The aim of this paper is to study the failure of the electrodeposited Co-W and Fe-W alloys onto copper and steel substrates by the indentation technique, examine plastic strain distributions around indentations and evaluate behaviour of the system "coating-substrate". The alloys of Co-W and Fe-W obtained electrodeposited from citrate-ammmonia baths are nanocrystalline. The values of grain size were evaluated based on the XRD spectrum and show values 30 - 37 angstrom. An experimental investigation into the Vickers indentation hardness and associated plastic deformation in electrochemically performed coatings was conducted. The methodology applied for this study allows obtaining the qualitative data to describe the behaviour of the system "coating-substrate", when both are deforming plastically. Implications of this study in understanding the mechanical behaviour of coatings and their derivatives are discussed.