Surface mechanical characterization of sputtered nickel using nanoindentation

The surface of carbon steel (CS) samples was deposited with pure Ni for the durations of 2, 5 and 10 minutes using DC magnetron sputter deposition process. The aim was to examine the microstructure and surface mechanical properties of Ni coatings. Field emission scanning electron microscope coupled with an energy dispersive x-ray spectrometer and x-ray diffractometer were used to undertake materials characterization. Instrumented nanoindentation hardness, elastic modulus, adhesion and coefficients of friction of coatings were evaluated. Nickel coatings obtained were relatively uniform, continuous and adherent for all deposition times. Thickness of Ni coatings increased with deposition times. Coatings with lower deposition times showed relatively higher nanohardness, elastic modulus and creep which is thought to be due to its lower thickness. Coatings were found to crack and delaminate at relatively low applied normal force during micro-scratch testing. Coefficient of friction values of coatings was comparable with that found in the literature.