MICROSTRUCTURAL EVALUATION OF NANOCRYSTALLINE COBALT-IRON-NICKEL THIN FILMS ELECTRODEPOSITED FROM CITRATE-FREE AND CITRATE-ADDED BATHS

Abstract

The microstructures of nanocrystalline CoFeNi thin films in direct current electrodeposition, under various processing conditions, have comparatively been investigated. Morphological studies by SEM showed that CoFeNi films plated from the sodium citrate-added baths were more uniform and denser than those deposited from the conventional citrate-free baths. Energy dispersive spectroscopy (EDS) showed the anomalous behaviors in electrodeposition of CoFeNi films from both citrate-added and citrate-free baths. It was also noticed that addition of 10g/L sodium citrate in the bath strongly decreases the iron content and increases nickel contents of the deposit. Addition of citrate up to 50g/L in the bath has reverse effect on the film composition. Further addition of sodium citrate appears to have no or little effect on the film composition. Addition of sodium citrate to the bath has no significant affect on the cobalt content of the deposit. XRD analyses showed that all CoFeNi films were nanocrystalline and their average grain sizes, estimated by Scherrer formula, were below 80nm. It was also noticed that FCC and BCC phases could be co-deposited in electroplated CoFeNi films by controlling the bath composition and/or the plating conditions.